Papers are indexed using the following keywords:
Machine learning.
  • active: active learning
  • ANN: artificial neural network
  • AR: autoregressive
  • DL: dictionary learning (structured sparse)
  • ICA: independent component/subspace/process analysis
  • MA: moving average
  • NP: nonparametric
  • RL: reinforcement learning
  • RNN: recurrent networks
  • RP: random projections
Applications.
  • AAC: alternative and augmented communication
  • CF: collaborative filtering
  • FACE: facial expression analysis, emotion estimation
  • HW: hardware
  • IR: information retrieval
  • NLP: natural language processing
  • web: web crawler
Systems.
  • AGI: artificial general intelligence
  • AmI: ambient intelligence
  • MAS: multi-agent systems
  • MEMS: smart dust
Models.
  • BG: basal-ganglia
  • complexity
  • EOL: emergence of language
  • HC: hippocampus
  • social: social science

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    Author Title Year Journal/Proceedings BibTeX type Keywords
    Jeni, L. A., Lőrincz, A., Szabó, Z., Cohn, J. F. & Kanade, T. Spatio-temporal Event Classification Using Time-Series Kernel Based Structured Sparsity 2014 Computer Vision -- ECCV   incollection
    BibTeX:
    @incollection{jeni14spatio,
      author = {L. A. Jeni and A. L{\H{o}}rincz and Z. Szab{\'o} and J. F. Cohn and T. Kanade},
      title = {Spatio-temporal Event Classification Using Time-Series Kernel Based Structured Sparsity},
      booktitle = {Computer Vision -- ECCV},
      year = {2014},
      volume = {8692},
      series = {Lecture Notes in Computer Science},
      pages = {135-150},
      isbn = {978-3-319-10592-5},
      doi = {10.1007/978-3-319-10593-2_10},
      url = {http://dx.doi.org/10.1007/978-3-319-10593-2_10},
    }					
    Miksztai-Réthey, B. & Kalman, S. L. Sentence prediction for a picture based vocabulary: problems of understanding and clarity – Preliminary results 2014 16th Biennial Conference of the International Society for Augmentative and Alternative Communication   inproceedings
    BibTeX:
    @inproceedings{miksztai2014sentence,
      author = {B. Miksztai-R{\'e}they and S. L. Kalman},
      title = {Sentence prediction for a picture based vocabulary: problems of understanding and clarity – Preliminary results},
      booktitle = {16th Biennial Conference of the International Society for Augmentative and Alternative Communication},
      year = {2014},
      address = {Lisbon},
      month = {July},
      url = {http://openconf.faiddsolutions.com/modules/request.php?module=oc_program&action=program.php&p=program},
    }					
    Németh, A., Sárkány, A., Verő, A. L., Vörös, Gy. & Lőrincz, A. Talking non-speaking taleteller: Android robotic and sensing tool 2014 6ème Challenge Handicap et Technologie   inproceedings
    BibTeX:
    @inproceedings{nemeth2014talking,
      author = {A. N{\'e}meth and A. S{\'a}rk{\'a}ny and A. L. Ver{\H{o}} and {\Gy}. V{\"o}r{\"o}s and A. L{\H{o}}rincz},
      title = {Talking non-speaking taleteller: Android robotic and sensing tool},
      booktitle = {6\`{e}me Challenge Handicap et Technologie},
      year = {2014},
      address = {Lille, France},
      month = {May},
    }					
    Palotai, Zs., Lánd, M., Sárkány, A., Tősér, Z., Sonntag, D., Toyama, T. & Lőrincz, A. LabelMovie: Semi-supervised machine annotation tool with quality assurance and crowd-sourcing options for videos 2014 12th International Workshop on Content-Based Multimedia Indexing (CBMI)   inproceedings
    BibTeX:
    @inproceedings{palotai14LabelMovie,
      author = {{\Zs}. Palotai and M. L{\'a}nd and A. S{\'a}rk{\'a}ny and Z. T{\H{o}}s{\'e}r and D. Sonntag and T. Toyama and A. L{\H{o}}rincz},
      title = {{L}abel{M}ovie: Semi-supervised machine annotation tool with quality assurance and crowd-sourcing options for videos},
      booktitle = {12th International Workshop on Content-Based Multimedia Indexing (CBMI)},
      year = {2014},
      pages = {1-4},
      month = {June},
      doi = {10.1109/CBMI.2014.6849850},
      url = {http://ieeexplore.ieee.org/xpl/abstractKeywords.jsp?arnumber=6849850},
    }					
    Sárkány, A., Lőrincz, A., Orlosky, J., Toyama, T. & Sonntag, D. On-body multi-input indoor localization for dynamic emergency scenarios: fusion of magnetic tracking and optical character recognition with mixed-reality display 2014 IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOM Workshops)   inproceedings
    BibTeX:
    @inproceedings{sarkany14onbody,
      author = {A. S{\'a}rk{\'a}ny and A. L{\H{o}}rincz and J. Orlosky and T. Toyama and D. Sonntag},
      title = {On-body multi-input indoor localization for dynamic emergency scenarios: fusion of magnetic tracking and optical character recognition with mixed-reality display},
      booktitle = {IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOM Workshops)},
      year = {2014},
      pages = {320-325},
      month = {March},
      doi = {10.1109/PerComW.2014.6815225},
      url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6815225},
    }					
    Sonntag, D., Zillner, S., Chakraborty, S., Lőrincz, A., Strommer, E. & Serafini, L. The Medical Cyber-physical Systems Activity at EIT: A Look Under the Hood 2014 Proceedings of the 2014 IEEE 27th International Symposium on Computer-Based Medical Systems   inproceedings
    BibTeX:
    @inproceedings{sonntag14medical,
      author = {D. Sonntag and S. Zillner and S. Chakraborty and A. L{\H{o}}rincz and E. Strommer and L. Serafini},
      title = {The Medical Cyber-physical Systems Activity at {EIT}: A Look Under the Hood},
      booktitle = {Proceedings of the 2014 IEEE 27th International Symposium on Computer-Based Medical Systems},
      year = {2014},
      series = {CBMS '14},
      pages = {351--356},
      address = {Washington, DC, USA},
      publisher = {IEEE Computer Society},
      isbn = {978-1-4799-4435-4},
      doi = {10.1109/CBMS.2014.83},
      url = {http://dx.doi.org/10.1109/CBMS.2014.83},
    }					
    Tettamanti, T., Milacski, Z. Á., Lőrincz, A. & Varga, I. Iterative calibration method for microscopic road traffic simulators 2014 Periodica Polytechnica   article
    Abstract: Recently, computer simulation aided work has become a standard routine in all engineering fields. Accordingly, simulation plays a fundamental role even in road traffic engineering. A reliable simulator is able to provide effective analysis of a given traffic network if the applied simulation scenarios properly converge to the real-word situation. This requirement can be achieved based on the mixed use of prior real-world traffic measurements and proper simulation settings. The latter one, however, is not straightforward. Accordingly, the paper investigates a potential calibration technique to create realistic simulations. Basically, a tuning method with genetic algorithm is proposed to reproduce true-to-life traffic based on floating car speed data.
    BibTeX:
    @article{tettamanti14iterative,
      author = {T. Tettamanti and Z. {\'A}. Milacski and A. L{\H{o}}rincz and I. Varga},
      title = {Iterative calibration method for microscopic road traffic simulators},
      journal = {Periodica Polytechnica},
      year = {2014},
      pages = {accepted},
    }					
    Verő, A. L. Comparison of different methods for Semantic Evaluation of symbol series based on language model generation and common sense knowledge 2014 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{vero14comparison,
      author = {A. L. Ver{\H{o}}},
      title = {Comparison of different methods for Semantic Evaluation of symbol series based on language model generation and common sense knowledge},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2014},
      address = {Budapest},
    }					
    Verő, A. L., Miksztai-Réthey, B., Vörös, Gy., Zsigmond, Á., Pintér, B., Toyama, T., Orlosky, J., Sonntag, D. & Lőrincz, A. Gaze Tracking and Language Model for Flexible Augmentative and Alternative Communication in Practical Scenarios 2014 16th Biennial Conference of the International Society for Augmentative and Alternative Communication   inproceedings
    BibTeX:
    @inproceedings{vero2014gaze,
      author = {A. L. Ver{\H{o}} and B. Miksztai-R{\'e}they and {\Gy}. V{\"o}r{\"o}s and {\'A}. Zsigmond and B. Pint{\'e}r and T. Toyama and J. Orlosky and D. Sonntag and A. L{\H{o}}rincz},
      title = {Gaze Tracking and Language Model for Flexible Augmentative and Alternative Communication in Practical Scenarios},
      booktitle = {16th Biennial Conference of the International Society for Augmentative and Alternative Communication},
      year = {2014},
      month = {July},
      url = {http://openconf.faiddsolutions.com/modules/request.php?module=oc_program&action=program.php&p=program},
    }					
    Vörös, Gy., Verő, A. L., Pintér, B., Miksztai-Réthey, B., Toyama, T., Lőrincz, A. & Sonntag, D. Towards a Smart Wearable Tool to Enable People with SSPI to Communicate by Sentence Fragments 2014 4th International Symposium on Pervasive Computing Paradigms for Mental Health (MindCare)   inproceedings
    BibTeX:
    @inproceedings{voros14towards,
      author = {{\Gy}. V{\"o}r{\"o}s and A. L. Ver{\H{o}} and B. Pint{\'e}r and B. Miksztai-R{\'e}they and T. Toyama and A. L{\H{o}}rincz and D. Sonntag},
      title = {Towards a Smart Wearable Tool to Enable People with SSPI to Communicate by Sentence Fragments},
      booktitle = {4th International Symposium on Pervasive Computing Paradigms for Mental Health (MindCare)},
      year = {2014},
      address = {Tokyo, Japan},
      month = {May},
    }					
    Vörös, Gy., Miksztai-Réthey, B., Verő, A. L., Toyama, T., Orlosky, J., Sonntag, D. & Lőrincz, A. Mobile AAC Solutions using Gaze Tracking and Optical Character Recognition 2014 16th Biennial Conference of the International Society for Augmentative and Alternative Communication   inproceedings
    BibTeX:
    @inproceedings{voros2014mobile,
      author = {{\Gy}. V{\"o}r{\"o}s and B. Miksztai-R{\'e}they and A. L. Ver{\H{o}} and T. Toyama and J. Orlosky and D. Sonntag and A. L{\H{o}}rincz},
      title = {Mobile AAC Solutions using Gaze Tracking and Optical Character Recognition},
      booktitle = {16th Biennial Conference of the International Society for Augmentative and Alternative Communication},
      year = {2014},
      address = {Lisbon},
      month = {July},
      url = {http://openconf.faiddsolutions.com/modules/request.php?module=oc_program&action=program.php&p=program},
    }					
    Kozsik, T., Lőrincz, A., Juhász, D., Domoszlai, L., Horpácsi, D., Tóth, M. & Horváth, Z. Workflow Description in Cyber-Physical Systems 2013 Studia Universitatis Babes-Bolyai, Informatica   article
    BibTeX:
    @article{kozsik2013workflow,
      author = {T. Kozsik and A. L{\H{o}}rincz and D. Juh{\'a}sz and L. Domoszlai and D. Horp{\'a}csi and M. T{\'o}th and Z. Horv{\'a}th},
      title = {Workflow Description in {C}yber-{P}hysical {S}ystems},
      journal = {Studia Universitatis Babes-Bolyai, Informatica},
      year = {2013},
      volume = {58},
      number = {2},
      pages = {20-30},
    }					
    Lőrincz, A., Jeni, L., Szabó, Z., Cohn, J. & Kanade, T. High Performance Emotion Classification using Time-Series Kernels 2013 IEEE International Workshop on Analysis and Modeling of Faces and Gestures (AMFG)   inproceedings FACE
    Abstract: Recent advances in kernel methods are very promising for improving the estimation, clustering and classification of spatio-temporal processes. Facial expression estimation can take advantage of such methods if one considers marker positions and their motion in 3D space. We applied support vector classification with kernels derived from dynamic time-warping similarity measures. We achieved excellent results using only the 'motion pattern' of the PCA compressed representation of the marker point vector, the socalled shape parameters. Beyond the classification of full motion patterns, the classification of the initial phase of an emotion (i) is competitive with methods relying on textural information and (ii) has complementary advantages to texture based algorithms reinforcing the need for mixed approaches.
    BibTeX:
    @inproceedings{lorincz13high,
      author = {A. L{\H{o}}rincz and L. Jeni and Z. Szab{\'o} and J. Cohn and T. Kanade},
      title = {High Performance Emotion Classification using Time-Series Kernels},
      booktitle = {IEEE International Workshop on Analysis and Modeling of Faces and Gestures (AMFG)},
      year = {2013},
      address = {Portland, Oregon},
      month = {28~June},
      note = {(accepted)},
    }					
    Lőrincz, A. & Pintér, B. Natural Language Processing supported transdisciplinary crowdsourcing 2013 Third EUCogIII Members Conference (MLCOGS)   inproceedings NLP, SSC
    Abstract: We present a Web-based architecture that serves the construction of transdisciplinary knowledge and is supported by machine intelligence.
    BibTeX:
    @inproceedings{lorincz13natural,
      author = {A. L{\H{o}}rincz and B. Pint{\'e}r},
      title = {Natural Language Processing supported transdisciplinary crowdsourcing},
      booktitle = {Third EUCogIII Members Conference (MLCOGS)},
      year = {2013},
      address = {Palma de Mallorca},
      month = {10-11~April},
    }					
    Lőrincz, A., Jeni, L., Szabó, Z., Cohn, J. & Kanade, T. Emotional Expression Classification using Time-Series Kernels 2013   techreport
    BibTeX:
    @techreport{lorincz2013emotional,
      author = {A. L{\H{o}}rincz and L. Jeni and Z. Szab{\'o} and J. Cohn and T. Kanade},
      title = {Emotional Expression Classification using Time-Series Kernels},
      year = {2013},
      address = {Budapest},
      url = {http://arxiv.org/abs/1306.1913},
    }					
    Lőrincz, A., Molnár, Gy., Jeni, L. A., Tőser, Z., Rausch, A., Cohn, J. F. & Csapó, B. Towards entertaining and efficient educational games 2013 NIPS Workshop on Data Driven Education   inproceedings
    BibTeX:
    @inproceedings{lorincz2013towards,
      author = {A. L{\H{o}}rincz and {\Gy}. Molnár and L. A. Jeni and Z. T{\H{o}}ser and A. Rausch and J. F. Cohn and B. Csap{\'o}},
      title = {Towards entertaining and efficient educational games},
      booktitle = {NIPS Workshop on Data Driven Education},
      year = {2013},
      address = {Lake Tahoe, Nevada, USA},
      month = {Dec},
      url = {http://lytics.stanford.edu/datadriveneducation/papers/lorinczetal.pdf},
    }					
    Pintér, B., Vörös, Gy., Palotai, Zs., Szabó, Z. & Lőrincz, A. Determining Unintelligible Words from their Textual Contexts 2013 Procedia - Social and Behavioral Sciences   article NLP, SSC
    Abstract: We propose a method to determine unintelligible words based on the textual context of the word determined. As there can be many different candidate words to choose from for a word, a robust, large-scale method is needed. The large scale makes the problem sensitive to spurious similarities of contexts: when the contexts of two, different words are similar. To reduce this effect, we induce structured sparsity on the words by formulating the task as a group Lasso problem. We compare this formulation to a k-nearest neighbor and a support vector machine based approach, and find that group Lasso outperforms both by a large margin. We achieve up to 75% of accuracy when determining the word from among 1000 candidate words both on the Brown corpus and on the British National Corpus. The relevance of this work is in Optical Character Recognition (OCR), where unintelligible words are often produced. Our proposed method utilizes information independent from information used in OCR and in turn, one expects that a combined approach could be very successful.
    BibTeX:
    @article{pinter13determining,
      author = {B. Pint{\'e}r and {\Gy}. V{\"o}r{\"o}s and {\Zs}. Palotai and Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Determining Unintelligible Words from their Textual Contexts},
      journal = {Procedia - Social and Behavioral Sciences},
      year = {2013},
      volume = {73},
      pages = {101-108},
      note = {Proceedings of the 2nd International Conference on Integrated Information (IC-ININFO 2012), Budapest, Hungary, 30 August - 3 September},
      doi = {http://dx.doi.org/10.1016/j.sbspro.2013.02.028},
    }					
    Pintér, B., Vörös, Gy., Szabó, Z. & Lőrincz, A. Explaining unintelligible words by means of their context 2013 International Conference on Pattern Recognition Applications and Methods (ICPRAM)   inproceedings NLP, SSC
    Abstract: Explaining unintelligible words is a practical problem for text obtained by optical character recognition, from the Web (e.g., because of misspellings), etc. Approaches to wikification, to enriching text by linking words to Wikipedia articles, could help solve this problem. However, existing methods for wikification assume that the text is correct, so they are not capable of wikifying erroneous text. Because of errors, the problem of disambiguation (identifying the appropriate article to link to) becomes large-scale: as the word to be disambiguated is unknown, the article to link to has to be selected from among hundreds, maybe thousands of candidate articles. Existing approaches for the case where the word is known build upon the distributional hypothesis: words that occur in the same contexts tend to have similar meanings. The increased number of candidate articles makes the difficulty of spuriously similar contexts (when two contexts are similar but belong to different articles) more severe. We propose a method to overcome this difficulty by combining the distributional hypothesis with structured sparsity, a rapidly expanding area of research. Empirically, our approach based on structured sparsity compares favorably to various traditional classification methods.
    BibTeX:
    @inproceedings{pinter13explaining,
      author = {B. Pint{\'e}r and {\Gy}. V{\"o}r{\"o}s and Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Explaining unintelligible words by means of their context},
      booktitle = {International Conference on Pattern Recognition Applications and Methods (ICPRAM)},
      year = {2013},
      address = {Barcelona, Spain},
      month = {15-18~February},
    }					
    Pintér, B., Vörös, Gy., Szabó, Z. & Lőrincz, A. Wikifying novel words to mixtures of Wikipedia senses by structured sparse coding 2013 Advances in Intelligent and Soft Computing   incollection NLP, SSC
    Abstract: We extend the scope of Wikification to novel words by relaxing two premises of Wikification: (i) we wikify without using the surface form of the word (ii) to a mixture of Wikipedia senses instead of a single sense. We identify two types of ''novel'' words: words where the connection between their surface form and their meaning is broken (e.g., a misspelled word), and words where there is no meaning to connect to -- the meaning itself is also novel. We propose a method capable of wikifying both types of novel words while also dealing with the inherently large-scale disambiguation problem. We show that the method can disambiguate between up to 1000 Wikipedia senses, and it can explain words with novel meaning as a mixture of other, possibly related senses. This mixture representation compares favorably to the widely used bag of words representation.
    BibTeX:
    @incollection{pinter13wikifying,
      author = {B. Pint{\'e}r and {\Gy}. V{\"o}r{\"o}s and Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Wikifying novel words to mixtures of {W}ikipedia senses by structured sparse coding},
      booktitle = {Advances in Intelligent and Soft Computing},
      year = {2013},
      editor = {Janusz Kacprzyk},
      publisher = {Springer},
      note = {(ISSN: 1867-5662; accepted)},
    }					
    Csapó, B., Lőrincz, A. & Molnár, Gy. Innovative Assessment Technologies in Educational Games Designed for Young Students 2012   inbook
    Abstract: Our research has focused on developing an Online Diagnostic Assessment System (ODAS) for the first six grades of primary school. The main aims of the current phase of the ODAS project are (1) to establish a system for assessing the progress of students in several dimensions of cognitive development; (2) to explore the possibilities technology-based assessment offers for a better understanding of students' cognition, especially reasoning of students with learning difficulties; and (3) to develop methods for compensating the diagnosed developmental deficiencies and for accelerating the development of some specific and general skills. Computer games are considered as one of the best means of interventions fostering the development of basic reasoning skills. The work that forms the empirical basis of this chapter can be characterized by four distinguishing features. (1) Designing games is driven by specific educational purposes. The activities of the games correspond to knowledge and skills identified in the assessment frameworks. (2) The games are designed for young children; therefore, they have to meet several specific requirements. (3) Innovative assessment technologies are explored by logging and analyzing metadata, such as keystrokes, mouse movement, head movement, and facial expressions (captured by web camera). (4) Assessment tools intend to monitor both cognitive (e.g., reasoning, speed carrying out operations) and affective (motivation, interest, boredom, fatigue) processes. The chapter summarizes the theoretical (cognitive psychological, educational and information technological) background of the ODAS project and reports the results of a pilot intervention with some general conclusions for further research.
    BibTeX:
    @inbook{csapo12innovative,
      author = {B. Csap{\'o} and A. L{\H{o}}rincz and {\Gy}. Moln{\'a}r},
      title = {Innovative Assessment Technologies in Educational Games Designed for Young Students},
      year = {2012},
      editor = {Dirk Ifenthaler and Deniz Eseryel and Xun Ge},
      pages = {235-254},
      publisher = {Springer},
      doi = {http://dx.doi.org/10.1007/978-1-4614-3546-4_13},
    }					
    Fogarasi, A., Szirtes, G., Zsiák, G. & Lőrincz, A. Improving seizure recognition by visual reinforcement 2012 Neurology, Psychiatry and Brain Research   article
    Abstract: Objective: Exact seizure description is an important diagnostic tool of epilepsy; however, epileptologists frequently get misleading data from lay eyewitnesses. The aim of this study is to find new methods for efficient training of seizure observation. Methods: Twelve video-recorded seizures were observed by four groups of subjects with different expertise level in epilepsy: (1) naive observers, (2) pediatric residents, (3) epilepsy nurses, and (4) experts in video-EEG monitoring. In half of the experiments, relevant parts of seizures were highlighted to direct the subjects' gaze during observations. Eye motion data of the observers were recorded by a Tobii T120 Eye Tracking system. After watching a seizure, subjects were asked to fill out a questionnaire regarding semiology data. To reinforce associations between verbal and visual information, subjects watched again the same clip. Observation skill improvement was accessed by comparing questionnaire scores and eye fixation data. Results: Questionnaire mean scores increased and deviations decreased through the study demonstrating overall improvement for each group. Fixation time values were shorter in more experienced observers, however, this difference diminished by time reflecting the effect of the learning process. The chosen method for visual highlighting did not facilitate learning. Conclusions: Our pilot study -- using eye-tracking assessment in clinical epileptology for the first time -- shows that seizure observational skills can be significantly facilitated by a combined use of video examples and questionnaires. With the increasing popularity of eyetracking methods in applied sciences, our results may lead to novel approaches in epilepsy education of both lay subjects and professionals.
    BibTeX:
    @article{fogarasi12improving,
      author = {A. Fogarasi and G. Szirtes and G. Zsi{\'a}k and A. L{\H{o}}rincz},
      title = {Improving seizure recognition by visual reinforcement},
      journal = {Neurology, Psychiatry and Brain Research},
      year = {2012},
      volume = {18},
      pages = {1-7},
      doi = {http://dx.doi.org/10.1016/j.npbr.2011.10.002},
    }					
    Jeni, L., Lőrincz, A., Nagy, T., Palotai, Zs., Sebők, J., Szabó, Z. & Takács, D. 3D Shape Estimation in Video Sequences Provides High Precision Evaluation of Facial Expressions 2012 Image and Vision Computing   article FACE
    Abstract: Person independent and pose invariant estimation of facial expressions and action unit (AU) intensity estimation is important for situation analysis and for automated video annotation. We evaluated raw 2D shape data of the CK+ database, used Procrustes transformation and the multi-class SVM leave-one-out method for classification. We found close to 100% performance demonstrating the relevance and the strength of details of the shape. Precise 3D shape information was computed by means of Constrained Local Models (CLM) on video sequences. Such sequences offer the opportunity to compute a time-averaged '3D Personal Mean Shape' (PMS) from the estimated CLM shapes, which -- upon subtraction -- gives rise to person independent emotion estimation. On CK+ data PMS showed significant improvements over AU0 normalization; performance reached and sometimes surpassed state-of-the-art results on emotion classification and on AU intensity estimation. 3D PMS from 3D CLM offers pose invariant emotion estimation that we studied by rendering a 3D emotional database for different poses and different subjects from the BU 4DFE database. Frontal shapes derived from CLM fits of the 3D shape were evaluated. Results demonstrate that shape estimation alone can be used for robust, high quality pose invariant emotion classification and AU intensity estimation.
    BibTeX:
    @article{jeni12shape,
      author = {L. Jeni and A. L{\H{o}}rincz and T. Nagy and {\Zs}. Palotai and J. Seb{\H{o}}k and Z. Szab{\'o} and D. Tak{\'a}cs},
      title = {{3D} Shape Estimation in Video Sequences Provides High Precision Evaluation of Facial Expressions},
      journal = {Image and Vision Computing},
      year = {2012},
      volume = {30},
      number = {10},
      pages = {785-795},
      doi = {http://dx.doi.org/10.1016/j.imavis.2012.02.003},
    }					
    Lőrincz, A., Palotai, Zs. & Szirtes, G. Efficient sparse coding in early sensory processing: lessons from signal recovery 2012 PLoS Computational Biology   article neuro, DL
    Abstract: Sensory representations are not only sparse, but often overcomplete: coding units significantly outnumber the input units. For models of neural coding this overcompleteness poses a computational challenge for shaping the signal processing channels as well as for using the large and sparse representations in an efficient way. We argue that higher level overcompleteness becomes computationally tractable by imposing sparsity on synaptic activity and we also show that such structural sparsity can be facilitated by statistics based decomposition of the stimuli into typical and atypical parts prior to sparse coding. Typical parts represent large-scale correlations, thus they can be significantly compressed. Atypical parts, on the other hand, represent local features and are the subjects of actual sparse coding. When applied on natural images, our decomposition based sparse coding model can efficiently form overcomplete codes and both center-surround and oriented filters are obtained similar to those observed in the retina and the primary visual cortex, respectively. Therefore we hypothesize that the proposed computational architecture can be seen as a coherent functional model of the first stages of sensory coding in early vision.
    BibTeX:
    @article{lorincz12efficient,
      author = {A. L{\H{o}}rincz and {\Zs}. Palotai and G. Szirtes},
      title = {Efficient sparse coding in early sensory processing: lessons from signal recovery},
      journal = {PLoS Computational Biology},
      year = {2012},
      volume = {8},
      number = {3},
      pages = {e1002372},
      month = {03},
      doi = {http://doi:10.1371/journal.pcbi.1002372},
    }					
    Lőrincz, A., Palotai, Zs. & Szirtes, G. Sparse and silent coding in neural circuits 2012 Neurocomputing   article
    Abstract: Sparse coding algorithms find a linear basis in which signals can be represented by a small number of non-zero coefficients. Such coding may play an important role in neural information processing and metabolically efficient natural solutions serve as an inspiration for algorithms employed in various areas of computer science. In particular, finding non-zero coefficients in overcomplete sparse coding is a computationally hard problem, for which different approximate solutions have been proposed. Methods that minimize the magnitude of the coefficients ('l1-norm') instead of minimizing the size of the active subset of features ('l0-norm') may find the optimal solutions, but they do not scale well with the problem size and use centralized algorithms. Iterative, greedy methods, on the other hand are fast, but require a priori knowledge of the number of non-zero features, often find suboptimal solutions and they converge to the final sparse form through a series of non-sparse representations. In this article we propose a neurally plausible algorithm which efficiently integrates an l0-norm based probabilistic sparse coding model with ideas inspired by novel iterative solutions. Furthermore, the resulting algorithm does not require an exactly defined sparseness level thus it is suitable for representing natural stimuli with a varying number of features. We demonstrate that our combined method can find optimal solutions in cases where other, l1-norm based algorithms already fail.
    BibTeX:
    @article{lorincz12sparse,
      author = {A. L{\H{o}}rincz and {\Zs}. Palotai and G. Szirtes},
      title = {Sparse and silent coding in neural circuits},
      journal = {Neurocomputing},
      year = {2012},
      volume = {79},
      pages = {115-124},
      doi = {http://dx.doi.org/10.1016/j.neucom.2011.10.017},
    }					
    Molnár, Gy. & Lőrincz, A. Innovative assessment technologies: Comparing 'face-to-face' and game-based development of thinking skills in classroom settings 2012 International Conference on Economics Marketing and Management (ICMEI)   inproceedings
    Abstract: Technology offers new opportunities for education including educational games and complex methods for assessment. This paper aims at comparing the cognitive and affective results of a training program developed for first- and second-grade students in face-to-face and game-based environment and at investigating the opportunities of applying educational games and embedded innovative assessment technologies to improve students' reasoning skills. The training program consists of 120 educational games, developed directly for young learners. The experimental and control groups in the study consisted of 123 and 137 first and second graders, respectively. One third of the experimental group took part in a game-based training in computer-based environment (n=38), the others were involved in face-to-face training. Trainers in the face-to-face case asked relevant questions before and after the tests, whereas no dialogues were present in the game-based case. The training took six weeks to complete. The cognitive effectiveness of the training was measured with an inductive reasoning test, comprising 37 figural, non-verbal items (Cronbach a=.87). Besides the test-based data collection, facial expressions and head movement (captured by webcams) were monitored and the affective effects of the training were logged. The experimental group significantly outperformed the control group by more than one standard deviation on the post-test (t=-10.65, p<.00). The most frequent facial expressions were surprise (31%), happiness (24%), and anger (16%) during game-based training. Disgust (7%), fear (3%), and sadness (1%) were less frequent. The distributions of the facial expressions did not show significant relationships with the developmental level of reasoning skills. On the whole we found no significant differences between the developmental achievements of the face-to-face and game based groups after the training.
    BibTeX:
    @inproceedings{molnar12innovative,
      author = {{\Gy}. Moln{\'a}r and A. L{\H{o}}rincz},
      title = {Innovative assessment technologies: Comparing 'face-to-face' and game-based development of thinking skills in classroom settings},
      booktitle = {International Conference on Economics Marketing and Management (ICMEI)},
      year = {2012},
      pages = {150-154},
    }					
    Pintér, B., Vörös, Gy., Szabó, Z. & Lőrincz, A. Automated Word Puzzle Generation Using Topic Models and Semantic Relatedness Measures 2012 Annales Universitatis Scientiarum Budapestinensis de Rolando Eötvös Nominatae, Sectio Computatorica   article NLP, DL
    Abstract: We propose a knowledge-lean method to generate word puzzles from unstructured and unannotated document collections. The presented method is capable of generating three types of puzzles: odd one out, choose the related word, and separate the topics. The difficulty of the puzzles can be adjusted. The algorithm is based on topic models, semantic similarity, and network capacity. Puzzles of two difficulty levels are generated: beginner and intermediate. Beginner puzzles could be suitable for, e.g., beginner language learners. Intermediate puzzles require more, often specific knowledge to solve. Domain-specific puzzles are generated from a corpus of NIPS proceedings. The presented method is capable of helping puzzle designers compile a collection of word puzzles in a semi-automated manner. In this setting, the method is utilized to produce a great number of puzzles. Puzzle designers can choose and maybe modify the ones they want to include in the collection.
    BibTeX:
    @article{pinter12automated2,
      author = {B. Pint{\'e}r and {\Gy}. V{\"o}r{\"o}s and Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Automated Word Puzzle Generation Using Topic Models and Semantic Relatedness Measures},
      journal = {Annales Universitatis Scientiarum Budapestinensis de Rolando E{\"o}tv{\"o}s Nominatae, Sectio Computatorica},
      year = {2012},
      volume = {36},
      pages = {299--322},
    }					
    Pintér, B., Vörös, Gy., Szabó, Z. & Lőrincz, A. Automated Word Puzzle Generation via Topic Dictionaries 2012 International Conference on Machine Learning (ICML) -- Sparsity, Dictionaries and Projections in Machine Learning and Signal Processing Workshop   inproceedings NLP, DL
    Abstract: We propose a general method for automated word puzzle generation. Contrary to previous approaches in this novel field, the presented method does not rely on highly structured datasets obtained with serious human annotation effort: it only needs an unstructured and unannotated corpus (i.e., document collection) as input. The method builds upon two additional pillars: (i) a topic model, which induces a topic dictionary from the input corpus (examples include e.g., latent semantic analysis, group-structured dictionaries or latent Dirichlet allocation), and (ii) a semantic similarity measure of word pairs. Our method can (i) generate automatically a large number of proper word puzzles of different types, including the odd one out, choose the related word and separate the topics puzzle. (ii) It can easily create domain-specific puzzles by replacing the corpus component. (iii) It is also capable of automatically generating puzzles with parameterizable levels of difficulty suitable for, e.g., beginners or intermediate learners.
    BibTeX:
    @inproceedings{pinter12automated3,
      author = {B. Pint{\'e}r and {\Gy}. V{\"o}r{\"o}s and Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Automated Word Puzzle Generation via Topic Dictionaries},
      booktitle = {International Conference on Machine Learning (ICML) -- Sparsity, Dictionaries and Projections in Machine Learning and Signal Processing Workshop},
      year = {2012},
      address = {Edinburgh, Scotland},
      month = {30~June},
      url = {http://www.di.ens.fr/~obozinski/ICML2012workshop/},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Collaborative Filtering via Group-Structured Dictionary Learning 2012 International Conference on Latent Variable Analysis and Signal Separation (LVA/ICA)   inproceedings DL, CF
    Abstract: Structured sparse coding and the related structured dictionary learning problems are novel research areas in machine learning. In this paper we present a new application of structured dictionary learning for collaborative filtering based recommender systems. Our extensive numerical experiments demonstrate that the presented method outperforms its state-of-the-art competitors and has several advantages over approaches that do not put structured constraints on the dictionary elements.
    BibTeX:
    @inproceedings{szabo12collaborative,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Collaborative Filtering via Group-Structured Dictionary Learning},
      booktitle = {International Conference on Latent Variable Analysis and Signal Separation (LVA/ICA)},
      year = {2012},
      editor = {Fabian Theis and Andrzej Cichocki and Arie Yeredor and Michael Zibulevsky},
      volume = {7191},
      series = {Lecture Notes in Computer Science},
      pages = {247--254},
      address = {Tel-Aviv, Israel},
      publisher = {Springer-Verlag, Berlin Heidelberg},
      doi = {http://dx.doi.org/10.1007/978-3-642-28551-6_31},
    }					
    Szabó, Z. & Lőrincz, A. Distributed High Dimensional Information Theoretical Image Registration via Random Projections 2012 Digital Signal Processing   article RP
    Abstract: Information theoretical measures, such as entropy, mutual information, and various divergences, exhibit robust characteristics in image registration applications. However, the estimation of these quantities is computationally intensive in high dimensions. On the other hand, consistent estimation from pairwise distances of the sample points is possible, which suits random projection (RP) based low dimensional embeddings. We adapt the RP technique to this task by means of a simple ensemble method. To the best of our knowledge, this is the first distributed, RP based information theoretical image registration approach. The efficiency of the method is demonstrated through numerical examples.
    BibTeX:
    @article{szabo12distributed,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Distributed High Dimensional Information Theoretical Image Registration via Random Projections},
      journal = {Digital Signal Processing},
      year = {2012},
      volume = {22},
      number = {6},
      pages = {894-902},
      doi = {http://dx.doi.org/10.1016/j.dsp.2012.04.018},
    }					
    Szabó, Z. Group-Structured and Independent Subspace Based Dictionary Learning 2012 School: Eötvös Loránd University   phdthesis active, ANN, AR, DL, ICA, MA, NP, RP
    BibTeX:
    @phdthesis{szabo12group,
      author = {Z. Szab{\'o}},
      title = {Group-Structured and Independent Subspace Based Dictionary Learning},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2012},
      address = {Budapest},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Separation theorem for independent subspace analysis and its consequences 2012 Pattern Recognition   article DL, ICA, AR, MA, NP
    Abstract: Independent component analysis (ICA) -- the theory of mixed, independent, non-Gaussian sources -- has a central role in signal processing, computer vision and pattern recognition. One of the most fundamental conjectures of this research field is that independent subspace analysis (ISA) -- the extension of the ICA problem, where groups of sources are independent -- can be solved by traditional ICA followed by grouping the ICA components. The conjecture, called ISA separation principle, (i) has been rigorously proven for some distribution types recently, (ii) forms the basis of the state-of-the-art ISA solvers, (iii) enables one to estimate the unknown number and the dimensions of the sources efficiently, and (iv) can be extended to generalizations of the ISA task, such as different linear-, controlled-, post nonlinear-, complex valued-, partially observed problems, as well as to problems dealing with nonparametric source dynamics. Here, we shall review the advances on this field.
    BibTeX:
    @article{szabo12separation,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Separation theorem for independent subspace analysis and its consequences},
      journal = {Pattern Recognition},
      year = {2012},
      volume = {45},
      pages = {1782-1791},
      doi = {http://dx.doi.org/10.1016/j.patcog.2011.09.007},
    }					
    Gyenes, V. Combinatorial -- Compositional Representations 2011 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{gyenes11combinatorial,
      author = {V. Gyenes},
      title = {Combinatorial -- Compositional Representations},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2011},
      address = {Budapest},
    }					
    Jeni, L., Hashimoto, H. & Lőrincz, A. Efficient, Pose Invariant Facial Emotion Classification using 3D Constrained Local Model and 2D Shape Information 2011 IEEE Computer Vision and Pattern Recognition (CVPR-2011) -- Workshop on Gesture Recognition   inproceedings ANN, AGI, AAC
    Abstract: Pose invariant facial emotion classification is important for situation analysis and for automated video annotation. We started from the raw 2D shape data of the CK+ database and used a simple Procrustes transformation and the multi-class SVM leave-one-out method for classification. We found close to 100% performance demonstrating the potentials of shape based methods. We applied a 3D constrained local model (CLM) and generated a 3D emotionally modulated database with different poses using FaceGen. We fitted 3D CLM and used it in an iterative manner to exclude the potentially occluded landmarks. We transformed the 3D shape to frontal pose and evaluated the outputs of our classifier. Excellent pose invariant performance with considerable improvement over the non-iterative method was achieved.
    BibTeX:
    @inproceedings{jeni11efficient,
      author = {L. Jeni and H. Hashimoto and A. L{\H{o}}rincz},
      title = {Efficient, Pose Invariant Facial Emotion Classification using {3D} Constrained Local Model and {2D} Shape Information},
      booktitle = {IEEE Computer Vision and Pattern Recognition (CVPR-2011) -- Workshop on Gesture Recognition},
      year = {2011},
      address = {Colorado Springs, CO, USA},
      month = {20~June},
    }					
    Jeni, L., Takács, D. & Lőrincz, A. High quality facial expression recognition in video streams using shape related information only 2011 ICCV Workshops   inproceedings FACE
    Abstract: Person independent and pose invariant facial emotion classification is important for situation analysis and for automated video annotation. Shape and its changes are advantageous for these purposes. We estimated the potentials of shape measurements from the raw 2D shape data of the CK+ database. We used a simple Procrustes transformation and applied the multi-class SVM leave-one-out method. We found close to 100% classification performance demonstrating the relevance of details in shape space. Precise, pose invariant 3D shape information can be computed by means of constrained local models (CLM). We used this method: we fitted 3D CLM to CK+ data and derived the frontal views of the 2D shapes. Performance reached and sometimes surpassed state-of-the-art results. In another experiment, we studied pose invariance: we rendered 3D emotional database with different poses using BU 4DFE database, fitted 3D CLM, transformed the 3D shape to frontal pose and evaluated the outputs of our classifier. Results show that the high quality classification is robust against pose variations. The superior performance suggests that shape, which is typically neglected or used only as side information in facial expression categorization, could make a good benchmark for future studies.
    BibTeX:
    @inproceedings{jeni11high,
      author = {L. Jeni and D. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {High quality facial expression recognition in video streams using shape related information only},
      booktitle = {ICCV Workshops},
      year = {2011},
      pages = {2168-2174},
      doi = {http://dx.doi.org/10.1109/ICCVW.2011.6130516},
    }					
    Lőrincz, A. & Takács, D. AGI Architecture Measures Human Parameters and Optimizes Human Performance 2011 Conference on Artificial General Intelligence (AGI-2011)   inproceedings RL, AGI, AAC
    Abstract: AGI could manifest itself in human-computer interactions. However, the computer should know what is on the mind of the user, since reinforcement learning, the main building block of AGI, is severely spoiled for partially observed states. Technological advances offer tools to uncover some of these hidden components of the 'state'. Here, for the first time, we apply an AGI architecture for the optimization of human performance. In particular, we measure facial parameters and optimize users' writing speed working with head motion controlled writing tool. We elaborate on how to extend this optimization scheme to more complex scenarios.
    BibTeX:
    @inproceedings{lorincz11AGI,
      author = {A. L{\H{o}}rincz and D. Tak{\'a}cs},
      title = {AGI Architecture Measures Human Parameters and Optimizes Human Performance},
      booktitle = {Conference on Artificial General Intelligence (AGI-2011)},
      year = {2011},
      editor = {J. Schmidhuber and K.R. Th{\'o}risson and M. Looks},
      volume = {6830},
      series = {Lecture Notes in in Artificial Intelligence},
      pages = {321-326},
      address = {Berlin Heidelberg},
      publisher = {Springer-Verlag},
    }					
    Lőrincz, A., Gyenes, V., Palotai, Zs., Pintér, B., Szabó, Z. & Vörös, Gy. Innovation Engine for Blogspaces 2011   techreport NLP, SSC, DL
    BibTeX:
    @techreport{lorincz11innovation,
      author = {A. L{\H{o}}rincz and V. Gyenes and {\Zs}. Palotai and B. Pint{\'e}r and Z. Szab{\'o} and {\Gy}. V{\"o}r{\"o}s},
      title = {Innovation Engine for Blogspaces},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2011},
      pages = {1-200},
      address = {Budapest},
      publisher = {EOARD - US Air Force Research Laboratories},
    }					
    Lőrincz, A. Learning the States: A Brain Inspired Neural Model 2011 Conference on Artificial General Intelligence (AGI-2011)   inproceedings ANN, RNN, HC, AGI
    Abstract: AGI relies on Markov Decision Processes, which assume deterministic states. However, such states must be learned. We propose that states are deterministic spatio-temporal chunks of observations and notice that learning of such episodic memory is attributed to the entorhinal hippocampal complex in the brain. EHC receives information from the neocortex and encodes learned episodes into neocortical memory traces thus it changes its input without changing its emerged representations. Motivated by recent results in exact matrix completion we argue that step-wise decomposition of observations into 'typical' (deterministic) and 'atypical' (stochastic) constituents is EHC's trick of learning episodic memory.
    BibTeX:
    @inproceedings{lorincz11learning,
      author = {A. L{\H{o}}rincz},
      title = {Learning the States: A Brain Inspired Neural Model},
      booktitle = {Conference on Artificial General Intelligence (AGI-2011)},
      year = {2011},
      editor = {J. Schmidhuber and K.R. Th{\'o}risson and M. Looks},
      volume = {6830},
      series = {Lecture Notes in in Artificial Intelligence},
      pages = {315-320},
      address = {Berlin Heidelberg},
      publisher = {Springer-Verlag},
    }					
    Matuz, G. & Lőrincz, A. Decision Making Agent Searching for Markov Models in Near-Deterministic World 2011   techreport RL
    Abstract: Reinforcement learning has solid foundations, but becomes inefficient in partially observed (non-Markovian) environments. Thus, a learning agent - born with a representation and a policy - might wish to investigate to what extent the Markov property holds. We propose a learning architecture that utilizes combinatorial policy optimization to overcome non-Markovity and to develop efficient behaviors, which are easy to inherit, tests the Markov property of the behavioral states, and corrects against non-Markovity by running a deterministic factored Finite State Model, which can be learned. We illustrate the properties of architecture in the near deterministic Ms. Pac-Man game. We analyze the architecture from the point of view of evolutionary, individual, and social learning.
    BibTeX:
    @techreport{matuz11decision_TR,
      author = {G. Matuz and A. L{\H{o}}rincz},
      title = {Decision Making Agent Searching for {Markov} Models in Near-Deterministic World},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2011},
      address = {Budapest},
      url = {http://arxiv.org/abs/1102.5561},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Online Group-Structured Dictionary Learning 2011 IEEE Computer Vision and Pattern Recognition (CVPR-2011)   inproceedings DL
    Abstract: We develop a dictionary learning method which is (i) online, (ii) enables overlapping group structures with (iii) non-convex sparsity-inducing regularization and (iv) handles the partially observable case. Structured sparsity and the related group norms have recently gained widespread attention in group-sparsity regularized problems in the case when the dictionary is assumed to be known and fixed. However, when the dictionary also needs to be learned, the problem is much more difficult. Only a few methods have been proposed to solve this problem, and they can handle two of these four desirable properties at most. To the best of our knowledge, our proposed method is the first one that possesses all of these properties. We investigate several interesting special cases of our framework, such as the online, structured, sparse non-negative matrix factorization, and demonstrate the efficiency of our algorithm with several numerical experiments.
    BibTeX:
    @inproceedings{szabo11online,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Online Group-Structured Dictionary Learning},
      booktitle = {IEEE Computer Vision and Pattern Recognition (CVPR-2011)},
      year = {2011},
      pages = {2865-2872},
      address = {Colorado Springs, CO, USA},
      month = {20-25~June},
      doi = {http://dx.doi.org/10.1109/CVPR.2011.5995712},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Online Dictionary Learning with Group Structure Inducing Norms 2011 International Conference on Machine Learning (ICML-2011) -- Structured Sparsity: Learning and Inference Workshop   inproceedings DL
    BibTeX:
    @inproceedings{szabo11structured,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Online Dictionary Learning with Group Structure Inducing Norms},
      booktitle = {International Conference on Machine Learning (ICML-2011) -- Structured Sparsity: Learning and Inference Workshop},
      year = {2011},
      address = {Bellevue, Washington, USA},
      month = {2~July},
    }					
    Fogarasi, A., Szirtes, G., Zsiák, G. & Lőrincz, A. Can Seizure Recognition be Improved? An Eye-Motion Study 2010 Epilepsia   article
    BibTeX:
    @article{fogarasi10seizure,
      author = {A. Fogarasi and G. Szirtes and G. Zsi{\'a}k and A. L{\H{o}}rincz},
      title = {Can Seizure Recognition be Improved? An Eye-Motion Study},
      journal = {Epilepsia},
      year = {2010},
      volume = {51},
      number = {4, SI},
      pages = {163-164},
    }					
    Lázár, K. A., Csuhaj-Varjú, E. & Lőrincz, A. On Eco-Foraging Systems 2010 Romanian Journal of Information Science and Technology   article
    Abstract: In this paper we present a formal language theoretic approach to Internet crawlers seeking novel information on the World Wide Web, based on a modified version of eco-grammar systems, called eco-foraging systems. In our model, the grammars correspond to very simple autonomous agents and the generated language to the behaviour of the system. In fact, the agents are represented by regulated rewriting devices, which impose some constraint on the search strategy of the agent. The letters of the generated strings symbolize the web pages. We prove that if we ignore the aging of the web environment in the model, then through the simulation of certain normal form grammars, the eco-foraging systems determine the class of recursively enumerable languages. If the web pages may become obsolete, then the language family generated by unordered scattered context grammars of finite index can be obtained. The ignorance of lifetime implies that the crawlers communicating only through the environment are able to identify any computable set of the environmental states. The lifetime constraint, however, considerably decreases the efficiency of the cooperation of the agents.
    BibTeX:
    @article{lazar10eco,
      author = {K. A. L{\'a}z{\'a}r and E. {Csuhaj-Varj{\'u}} and A. L{\H{o}}rincz},
      title = {On Eco-Foraging Systems},
      journal = {Romanian Journal of Information Science and Technology},
      year = {2010},
      volume = {13},
      number = {3},
      pages = {279-309},
    }					
    Lőrincz, A., Bárdosi, Z. & Takács, D. Sketch of an AGI architecture with illustration 2010 Conference on Artificial General Intelligence (AGI-2010)   inproceedings RL, ANN, RNN, AR, AGI, cog
    Abstract: Here we present a framework for AGI inspired by knowledge about the only working prototype: the brain. We consider the neurobiological findings as directives. The main algorithmic modules are defined and solutions for each subtasks are given together with the available mathematical (hard) constraints. The main themes are compressed sensing, factor learning, independent process analysis and low dimensional embedding for optimal state representation to be used by a particular RL system that can be integrated with a robust controller. However, the blending of the suggested partial solutions is not a straightforward task. Nevertheless we start to combine these modules and illustrate their working on a simulated problem. We will discuss the steps needed to complete the integration.
    BibTeX:
    @inproceedings{lorincz10sketch,
      author = {A. L{\H{o}}rincz and Z. B{\'a}rdosi and D. Tak{\'a}cs},
      title = {Sketch of an AGI architecture with illustration},
      booktitle = {Conference on Artificial General Intelligence (AGI-2010)},
      year = {2010},
      series = {Advances in Intelligent Systems Research},
      month = {March},
      note = {ISBN: 978-90-78677-36-9},
      doi = {http://dx.doi.org/10.2991/agi.2010.40},
    }					
    Lőrincz, A. Theoretical mysteries of the basal ganglia 2010 Acta Physiologica Hungarica   article BG
    BibTeX:
    @article{lorincz10theoretical,
      author = {A. L{\H{o}}rincz},
      title = {Theoretical mysteries of the basal ganglia},
      journal = {Acta Physiologica Hungarica},
      year = {2010},
      volume = {97},
      number = {1},
      pages = {88},
    }					
    Pintér, B., Bontovics, Á. & Lőrincz, A. Multiagent reinforcement learning model for the emergence of common property and transhumance in Sub-Saharan Africa 2010 Adaptive and Learning Agents, 2009   incollection RL, social, MAS
    Abstract: We consider social phenomena as challenges and measures for learning in multi-agent scenarios for the following reasons: (i) social phenomena emerge through complex learning processes of groups of people, (ii) a model of a phenomenon sheds light onto the strengths and weaknesses of the learning algorithm in the context of the model environment. In this paper we use tabular reinforcement learning to model the emergence of common property and transhumance in Sub-Saharan Africa. We find that the Markovian assumption is sufficient for the emergence of property sharing, when (a) the availability of resources fluctuates (b) the agents try to maximize their resource intake independently and (c) all agents learn simultaneously.
    BibTeX:
    @incollection{pinter10multiagent,
      author = {B. Pint{\'e}r and {\'A}. Bontovics and A. L{\H{o}}rincz},
      title = {Multiagent reinforcement learning model for the emergence of common property and transhumance in {Sub-Saharan Africa}},
      booktitle = {Adaptive and Learning Agents, 2009},
      year = {2010},
      editor = {M. Taylor and K. Tuyls},
      volume = {5924},
      series = {Lecture Notes in Computer Science},
      pages = {91-106},
      address = {Berlin Heidelberg},
      publisher = {Springer-Verlag},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Auto-Regressive Independent Process Analysis without Combinatorial Efforts 2010 Pattern Analysis and Applications   article ICA, AR
    Abstract: We treat the problem of searching for hidden multi-dimensional independent auto-regressive processes (Auto-Regressive Independent Process Analysis, AR-IPA). Independent Subspace Analysis (ISA) can be used to solve the AR-IPA task. The so-called separation theorem simplifies the ISA task considerably: the theorem enables one to reduce the task to 1-dimensional Blind Source Separation (BSS) task followed by the grouping of the coordinates. However, the grouping of the coordinates still involves 2 types of combinatorial problems: (i) the number of the independent subspaces and their dimensions, and then (ii) the permutation of the estimated coordinates are to be determined. Here, we generalize the separation theorem. We also show a non-combinatorial procedure, which under certain conditions can treat these 2 combinatorial problems. Numerical simulations have been conducted. We investigate problems that fulfill sufficient conditions of the theory and also others that do not. The success of the numerical simulations indicates that further generalizations of the separation theorem may be feasible.
    BibTeX:
    @article{szabo10autoregressive,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Auto-Regressive Independent Process Analysis without Combinatorial Efforts},
      journal = {Pattern Analysis and Applications},
      year = {2010},
      volume = {13},
      pages = {1-13},
      month = {February},
      doi = {http://dx.doi.org/10.1007/s10044-009-0174-x},
    }					
    Huhn, Zs., Szirtes, G., Lőrincz, A. & Csépe, V. Audiovisual integration in speech perception 2009 Frontiers in Systems Neuroscience   article
    Abstract: Speech comprehension is significantly improved by visual information originating from the inspection of the speaker's mouth movements. Audiovisual integration necessary for the existence of this phenomenon is often studied in EEG experiments by the comparison of the event related potential (ERP) evoked by a bimodal stimulus and the sum of ERPs triggered by the auditory and the visual modalities (AV versus A+V comparison). However, due to ERP components common to all these three types of stimulus, this analysis can only be applied to the first 200 ms poststimulus latency, and subsequent components (e.g. auditory P2 component) can not be studied by this method. Moreover, spurious results might emerge also in the analyzed 200 ms range due to common early anticipatory potentials. In order to circumvent methodological problems related to the AV versus A+V method, we suggest a different approach for the investigation of audiovisual integration: temporally slightly asynchronous bimodal syllable was presented to the subjects, which leaded to the development of either a fused or an unfused percept. ERPs belonging to the two different perceptions were compared. We found that components corresponding to both auditory N1 and P2 waves were smaller in case of the fused perception and the N1 effect showed a clearly right hemisphere dominance while the effect around the P2 peak was most pronounced on central electrodes. These results are in accordance with previous studies suggesting suppression of N1 generator activities during speech-related audiovisual interaction and suggest a similar phenomenon to subsequent processing stages too.
    BibTeX:
    @article{huhn09audiovisual,
      author = {{\Zs}. Huhn and G. Szirtes and A. L{\H{o}}rincz and V. Cs{\'e}pe},
      title = {Audiovisual integration in speech perception},
      journal = {Frontiers in Systems Neuroscience},
      year = {2009},
      doi = {http://dx.doi.org/10.3389/conf.neuro.01.2009.04.090},
    }					
    Huhn, Zs., Szirtes, G., Lőrincz, A. & Csépe, V. Perception based method for the investigation of audiovisual integration of speech 2009 Neuroscience Letters   article neuro, cog
    Abstract: Speech comprehension is significantly improved by visual input on the speaker's mouth movements. Audiovisual integration underlying this phenomenon is often studied in EEG experiments in which the event related brain potential (ERP) elicited by a bimodal stimulus is compared to the sum of ERPs triggered by auditory and visual signals of the same source. However, this method leads to spurious results in time ranges when ERP components common to all these stimulus types are present. A method that aims to filter out such common early anticipatory potentials is data high-pass filtering. In the present study, first, we demonstrated that subtle changes in filter cut-off frequency lead to remarkably different results on the interaction effect so that no reliable conclusion on the spatial distribution of the interaction could be drawn. Second, we suggested a different approach for the investigation of ERP correlates of audiovisual integration: bimodal syllables modified by light temporal asynchrony were presented to subjects and ERPs correlating with the fused and unfused perceptions were compared. We found that components corresponding to both auditory N1 and P2 waves were smaller in case of the fused perception, supporting the view that N1 and P2 generator activities are suppressed during multimodal speech perception. The N1 effect showed a clearly right hemisphere dominance while the effect around the P2 peak was most pronounced on centroparietal electrodes and dominated over the left hemisphere.
    BibTeX:
    @article{huhn09perception,
      author = {{\Zs}. Huhn and G. Szirtes and A. L{\H{o}}rincz and V. Cs{\'e}pe},
      title = {Perception based method for the investigation of audiovisual integration of speech},
      journal = {Neuroscience Letters},
      year = {2009},
      volume = {465},
      pages = {204--209},
    }					
    Lázár, K. A., Csuhaj-Varjú, E. & Lőrincz, A. Dynamically formed clusters of agents in eco-grammar systems 2009 International Journal of Foundations of Computer Science   article MAS
    Abstract: In this paper we extend the conditions of dynamic team constitution in simple eco--grammar systems, motivated by the bottom--up--clustering algorithm. The relationships of simple eco--grammar systems formed according to the newly introduced conditions to each other as well as to certain language classes of the Chomsky hierarchy and L systems are established. We prove that any recursively enumerable language can be obtained as the intersection of a regular language and the language of simple eco--grammar systems where the active teams are organized according to different conditions of team constitution. We also propose some further research directions.
    BibTeX:
    @article{lazar09dynamically,
      author = {K. A. L{\'a}z{\'a}r and E. {Csuhaj-Varj{\'u}} and A. L{\H{o}}rincz},
      title = {Dynamically formed clusters of agents in eco-grammar systems},
      journal = {International Journal of Foundations of Computer Science},
      year = {2009},
      volume = {20},
      pages = {293-311},
    }					
    Lőrincz, A. & Szirtes, G. Autoregressive model of the hippocampal representation of events 2009 International Joint Conference on Neural Networks (IJCNN 2009)   inproceedings HC, neuro, ARMA
    Abstract: The hippocampal formation is believed to play a central role in forming long lasting representation of events. However, in contrast to the continuous nature of sensory signal flow, events are spatially and temporally bounded processes. In this paper we are interested in the kind of representation that allows for detecting and/or predicting events. Based on new results on the identification problem of linear hidden processes, we propose a general signal encoding model that can represent causal relationships used to define events. We translate the model into a connectionist structure in which parameter learning follows biologically plausible rules. We also speculate on the resemblance of the resulting structure to the connection system of the hippocampal formation. When our signal encoding model is applied on spatially anchored inputs, its different parts feature spatially localized and periodic neural activity similar to those found in the hippocampus and in the entorhinal cortex, respectively. These emergent forms of spatial activity differentiates our model from other computational models of (spatial) memory as the model has not been explicitly designed to deal with spatial information. We speculate that our model may describe the core function of the hippocampal region in forming episodic memory and supporting spatial navigation.
    BibTeX:
    @inproceedings{lorincz09autoregressive,
      author = {A. L{\H{o}}rincz and G. Szirtes},
      title = {Autoregressive model of the hippocampal representation of events},
      booktitle = {International Joint Conference on Neural Networks (IJCNN 2009)},
      year = {2009},
      pages = {1885-1892},
      month = {14-19~June},
      note = {IEEE Catalog Number: CFP09IJS-CDR; ISBN: 978-1-4244-3553-1; ISSN: 1098-7576},
    }					
    Lőrincz, A. Hebbian Constraint on the Resolution of the Homunculus Fallacy Leads to a Network that Searches for Hidden Cause-Effect Relationships 2009 2nd Conference on Artificial General Intelligence (AGI-2009)   inproceedings AGI, HC, neuro, ARMA
    Abstract: We elaborate on a potential resolution of the homunculus fallacy that leads to a minimal and simple auto-associative recurrent 'reconstruction network' architecture. We insist on Hebbian constraint at each learning step executed in this network. We find that the hidden internal model enables searches for cause-effect relationships in the form of autoregressive models under certain conditions. We discuss the connection between hidden causes and Independent Subspace Analysis. We speculate that conscious experience is the result of competition between various learned hidden models for spatio-temporal reconstruction of ongoing effects of the detected hidden causes.
    BibTeX:
    @inproceedings{lorincz09hebbian,
      author = {A. L{\H{o}}rincz},
      title = {{Hebbian} Constraint on the Resolution of the {Homunculus} Fallacy Leads to a Network that Searches for Hidden Cause-Effect Relationships},
      booktitle = {2nd Conference on Artificial General Intelligence (AGI-2009)},
      year = {2009},
      editor = {Ben Goertzel and Pascal Hitzler and Marcus Hutter},
      volume = {8},
      series = {Advances in Intelligent Systems Research (ISSN: 1951-6851)},
      pages = {126-131},
      address = {Arlington, Virginia, USA},
      month = {6-9~March},
      publisher = {Atlantis Press},
      note = {ISBN: 978-90-78677-24-6},
    }					
    Lőrincz, A. & Szirtes, G. Here and now: how time segments may become events in the hippocampus 2009 Neural Networks   article HC, neuro, ARMA
    Abstract: The hippocampal formation is believed to play a central role in memory functions related to the representation of events. Events are usually considered as temporally bounded processes, in contrast to the continuous nature of sensory signal flow they originate from. Events are then organized and stored according to behavioral relevance and are used to facilitate prediction of similar events. In this paper we are interested in the kind of representation of sensory signals that allows for detecting and/or predicting events. Based on new results on the identification problem of linear hidden processes, we propose a connectionist network with biologically sound parameter tuning that can represent causal relationships and define events. Interestingly, the wiring diagram of our architecture not only resembles the gross anatomy of the hippocampal formation (including the entorhinal cortex), but it also features similar spatial distribution functions of activity (localized and periodic, 'grid-like' patterns) as found in the different parts of the hippocampal formation. We shortly discuss how our model corresponds to different theories on the role of the hippocampal formation in forming episodic memories or supporting spatial navigation. We speculate that our approach may constitute a step toward a unified theory about the functional role of the hippocampus and the structure of memory representations.
    BibTeX:
    @article{lorincz09here,
      author = {A. L{\H{o}}rincz and G. Szirtes},
      title = {Here and now: how time segments may become events in the hippocampus},
      journal = {Neural Networks},
      year = {2009},
      volume = {22},
      pages = {738-747},
    }					
    Lőrincz, A. Learning and Representation: From Compressive Sampling to the 'Symbol Learning Problem' 2009 Handbook of Large-Scale Random Networks   incollection AGI, ARMA, ICA, RL
    Abstract: In this paper a novel approach to neurocognitive modeling is proposed in which the central constraints are provided by the theory of reinforcement learning. In this formulation learning is (1) exploiting the statistical properties of the system's environment, (2) constrained by biologically inspired Hebbian interactions and (3) based only on algorithms which are consistent and stable. In the resulting model some of the most enigmatic problems of artificial intelligence have to be addressed. In particular, considerations on combinatorial explosion lead to constraints on the concepts of state-action pairs: these concepts have the peculiar flavor of determinism in a partially observed and thus highly uncertain world. We will argue that these concepts of factored reinforcement learning result in an intriguing learning task that we call the symbol learning problem. For this task we sketch an information theoretic framework and point towards a possible resolution.
    BibTeX:
    @incollection{lorincz09learning,
      author = {A. L{\H{o}}rincz},
      title = {Learning and Representation: From Compressive Sampling to the 'Symbol Learning Problem'},
      booktitle = {Handbook of Large-Scale Random Networks},
      year = {2009},
      editor = {B. Bollob{\'a}s and R. Kozma and M. Dezs{\H{o}}},
      volume = {18},
      series = {Bolyai Society Mathematical Studies},
      pages = {445-488},
      address = {Berlin, Germany},
      publisher = {Springer},
    }					
    Póczos, B. & Lőrincz, A. Identification of Recurrent Neural Networks by Bayesian Interrogation Techniques 2009 Journal of Machine Learning Research   article active, AR
    Abstract: We introduce novel online Bayesian methods for the identification of a family of noisy recurrent neural networks (RNNs). We present Bayesian active learning techniques for stimulus selection given past experiences. In particular, we consider the unknown parameters as stochastic variables and use A-optimality and D-optimality principles to choose optimal stimuli. We derive myopic cost functions in order to maximize the information gain concerning network parameters at each time step. We also derive the A-optimal and D-optimal estimations of the additive noise that perturbs the dynamical system of the RNN. Here we investigate myopic as well as non-myopic estimations, and study the problem of simultaneous estimation of both the system parameters and the noise. Employing conjugate priors our derivations remain approximation-free and give rise to simple update rules for the online learning of the parameters. The efficiency of our method is demonstrated for a number of selected cases, including the task of controlled independent component analysis.
    BibTeX:
    @article{poczos09identification,
      author = {B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Identification of Recurrent Neural Networks by {Bayesian} Interrogation Techniques},
      journal = {Journal of Machine Learning Research},
      year = {2009},
      volume = {10},
      pages = {515--554},
      month = {February},
    }					
    Szabó, Z. & Lőrincz, A. Complex Independent Process Analysis 2009 Acta Cybernetica   article ICA, ARMA
    Abstract: We present a general framework for the search of hidden independent processes in the complex domain. The task is to estimate the hidden independent multidimensional complex-valued components observing only the mixture of the processes driven by them. In our model (i) the hidden independent processes can be multidimensional, they may be subject to (ii) moving averaging, or may evolve in an autoregressive manner, or (iii) they can be non-stationary. These assumptions are covered by integrated autoregressive moving average processes and thus our task is to solve their complex extensions. We show how to reduce the undercomplete version of complex integrated autoregressive moving average processes to real independent subspace analysis that we can solve. Simulations illustrate the working of the algorithm.
    BibTeX:
    @article{szabo09complex,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Complex Independent Process Analysis},
      journal = {Acta Cybernetica},
      year = {2009},
      volume = {19},
      pages = {177-190},
      url = {http://www.inf.u-szeged.hu/actacybernetica/edb/vol19n1/pdf/Szabo_2009_ActaCybernetica.pdf},
    }					
    Szabó, Z. & Lőrincz, A. Controlled Complete ARMA Independent Process Analysis 2009 International Joint Conference on Neural Networks (IJCNN 2009)   inproceedings ICA, ARMA
    Abstract: In this paper we address the controlled complete AutoRegressive Moving Average Independent Process Analysis (ARMAX-IPA; X-exogenous input or control) problem, which is a generalization of the Blind SubSpace Deconvolution (BSSD) task. Compared to our previous work that dealt with the undercomplete situation, (i) here we extend the theory to complete systems, (ii) allow an autoregressive part to be present, (iii) and include exogenous control. We investigate the case when the observed signal is a linear mixture of independent multidimensional ARMA processes that can be controlled. Our objective is to estimate the ARMA processes, their driving noises as well as the mixing. We aim efficient estimation by choosing suitable control values. For the optimal choice of the control we adapt the D-optimality principle, also known as the `InfoMax method'. We solve the problem by reducing it to a fully observable D-optimal ARX task and Independent Subspace Analysis (ISA) that we can solve. Numerical examples illustrate the efficiency of the proposed method.
    BibTeX:
    @inproceedings{szabo09controlled,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Controlled Complete {ARMA} Independent Process Analysis},
      booktitle = {International Joint Conference on Neural Networks (IJCNN 2009)},
      year = {2009},
      pages = {3038-3045},
      month = {14-19~June},
      note = {IEEE Catalog Number: CFP09IJS-CDR; ISBN: 978-1-4244-3553-1; ISSN: 1098-7576},
      doi = {http://dx.doi.org/10.1109/IJCNN.2009.5178797},
    }					
    Szabó, Z. & Lőrincz, A. Fast Parallel Estimation of High Dimensional Information Theoretical Quantities with Low Dimensional Random Projection Ensembles 2009 Independent Component Analysis and Signal Separation (ICA 2009)   inproceedings RP
    Abstract: The estimation of relevant information theoretical quantities, such as entropy, mutual information, and various divergences is computationally expensive in high dimensions. However, for this task, one may apply pairwise Euclidean distances of sample points, which suits random projection (RP) based low dimensional embeddings. The Johnson-Lindenstrauss (JL) lemma gives theoretical bound on the dimension of the low dimensional embedding. We adapt the RP technique for the estimation of information theoretical quantities. Intriguingly, we find that embeddings into extremely small dimensions, far below the bounds of the JL lemma, provide satisfactory estimates for the original task.We illustrate this in the Independent Subspace Analysis (ISA) task; we combine RP dimension reduction with a simple ensemble method. We gain considerable speed-up with the potential of real-time parallel estimation of high dimensional information theoretical quantities.
    BibTeX:
    @inproceedings{szabo09fast,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Fast Parallel Estimation of High Dimensional Information Theoretical Quantities with Low Dimensional Random Projection Ensembles},
      booktitle = {Independent Component Analysis and Signal Separation (ICA 2009)},
      year = {2009},
      editor = {T{\"u}lay Adali and Christian Jutten and Jo{\~a}o Marcos T. Romano and Allan Kardec Barros},
      volume = {5441},
      series = {Lecture Notes in Computer Science},
      pages = {146-153},
      address = {Berlin Heidelberg},
      month = {15-18~March},
      publisher = {Springer-Verlag},
      doi = {http://dx.doi.org/10.1007/978-3-642-00599-2_19},
    }					
    Szabó, Z. Separation Principles in Independent Process Analysis 2009 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{szabo09separation,
      author = {Z. Szab{\'o}},
      title = {Separation Principles in Independent Process Analysis},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2009},
      address = {Budapest},
    }					
    Szita, I. & Lőrincz, A. Optimistic Initialization and Greediness Lead to Polynomial Time Learning in Factored MDPs 2009 International Conference on Machine Learning (ICML 2009)   inproceedings RL
    Abstract: In this paper we propose an algorithm for polynomial-time reinforcement learning in factored Markov decision processes (FMDPs). The factored optimistic initial model (FOIM) algorithm, maintains an empirical model of the FMDP in a conventional way, and always follows a greedy policy with respect to its model. The only trick of the algorithm is that the model is initialized optimistically. We prove that with suitable initialization (i) FOIM converges to the fixed point of approximate value iteration (AVI); (ii) the number of steps when the agent makes non-near-optimal decisions (with respect to the solution of AVI) is polynomial in all relevant quantities; (iii) the per-step costs of the algorithm are also polynomial. To our best knowledge, FOIM is the first algorithm with these properties.
    BibTeX:
    @inproceedings{szita09optimistic,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Optimistic Initialization and Greediness Lead to Polynomial Time Learning in Factored {MDP}s},
      booktitle = {International Conference on Machine Learning (ICML 2009)},
      year = {2009},
      editor = {L\'{e}on Bottou and Michael Littman},
      pages = {1001--1008},
      address = {Montreal},
      month = {June},
      publisher = {Omnipress},
    }					
    Gyenes, V., Bontovics, Á. & Lőrincz, A. Factored Temporal Difference Learning in the New Ties Environment 2008 Acta Cybernetica   article RL, social
    Abstract: Although reinforcement learning is a popular method for training an agent for decision making based on rewards, well studied tabular methods are not applicable for large, realistic problems. In this paper, we experiment with a factored version of temporal difference learning, which boils down to a linear function approximation scheme utilizing natural features coming from the structure of the task. We conducted experiments in the New Ties environment, which is a novel platform for multi-agent simulations. We show that learning utilizing a factored representation is effective even in large state spaces, furthermore it outperforms tabular methods even in smaller problems both in learning speed and stability, because of its generalization capabilities.
    BibTeX:
    @article{gyenes08factored,
      author = {V. Gyenes and {\'A}. Bontovics and A. L{\H{o}}rincz},
      title = {Factored Temporal Difference Learning in the {New} {Ties} Environment},
      journal = {Acta Cybernetica},
      year = {2008},
      volume = {18},
      pages = {651-668},
    }					
    Jeni, L., Flórea, Gy. & Lőrincz, A. InfoMax Bayesian Learning of the Furuta Pendulum 2008 Acta Cybernetica   article ANN, active, AR
    Abstract: We have studied the InfoMax (D-optimality) learning for the two-link Furuta pendulum. We compared InfoMax and random learning methods. The InfoMax learning method won by a large margin, it visited a larger domain and provided better approximation during the same time interval. The advantages and the limitations of the InfoMax solution are treated.
    BibTeX:
    @article{jeni08infomax,
      author = {L. Jeni and {\Gy}. Fl{\'o}rea and A. L{\H{o}}rincz},
      title = {InfoMax {Bayesian} Learning of the {Furuta} Pendulum},
      journal = {Acta Cybernetica},
      year = {2008},
      volume = {18},
      pages = {637-649},
    }					
    Jost, J., Helbing, D., Lőrincz, A. & Middendorf, M. Complexity in Biology, editorial 2008 Theory in Biosciences   article complexity
    BibTeX:
    @article{jost08editorial,
      author = {J. Jost and D. Helbing and A. L{\H{o}}rincz and M. Middendorf},
      title = {Complexity in Biology, editorial},
      journal = {Theory in Biosciences},
      year = {2008},
      volume = {127},
      pages = {67-68},
      doi = {http://dx.doi.org/10.1007/s12064-008-0042-z},
    }					
    Lázár, K. A., Csuhaj-Varjú, E. & Lőrincz, A. Peer-to-peer networks: A language theoretic approach 2008 Computing and Informatics   article MAS
    BibTeX:
    @article{lazar08p2p,
      author = {K. A. L{\'a}z{\'a}r and E. {Csuhaj-Varj{\'u}} and A. L{\H{o}}rincz},
      title = {Peer-to-peer networks: A language theoretic approach},
      journal = {Computing and Informatics},
      year = {2008},
      volume = {27},
      pages = {403-422},
    }					
    Lőrincz, A. Hippocampal Formation Breaks Combinatorial Explosion for Reinforcement Learning: A Conjecture 2008 AAAI 2008 Fall Symposium Series: Biologically Inspired Cognitive Architectures, Arlington, Virginia   inproceedings HC, RL, neuro, ARMA
    Abstract: There is surmounting evidence that reinforcement learning (RL) is a good model for the dopamine system of the brain and the prefrontal cortex. RL is also promising from the algorithmic point of view, because recent factored RL algorithms have favorable convergence and scaling properties and can counteract the curse of dimensionality problem, the major obstacle of practical applications of RL methods. Learning in navigation tasks then separates (i) to the search and the encoding of the factors, such as position, direction, and speed, and (ii) to the optimization of RL decision making by using these factors. We conjecture that the main task of the hippocampal formation is to separate factors and encode into neocortical areas the different low-dimensional conjunctive representations of them to suit factored RL value estimation. The mathematical framework is sketched. It includes convergent factored RL model and autoregressive (AR) hidden process model that finds factors including the hidden causes. The AR model is mapped to the hippocampal formation.
    BibTeX:
    @inproceedings{lorincz08hippocampal,
      author = {A. L{\H{o}}rincz},
      title = {Hippocampal Formation Breaks Combinatorial Explosion for Reinforcement Learning: A Conjecture},
      booktitle = {AAAI 2008 Fall Symposium Series: Biologically Inspired Cognitive Architectures, Arlington, Virginia},
      year = {2008},
      editor = {A. V. Samsonovich},
      address = {Menlo Park, CA},
      publisher = {AAAI Press},
    }					
    Lőrincz, A. Machine Situation Assessment and Assistance: Prototype for Severely Handicapped Children 2008 Proceedings of Regional Conference on Embedded and Ambient Systems, Selected Papers   inproceedings AAC, AmI
    BibTeX:
    @inproceedings{lorincz08machine,
      author = {A. L{\H{o}}rincz},
      title = {Machine Situation Assessment and Assistance: {P}rototype for Severely Handicapped Children},
      booktitle = {Proceedings of Regional Conference on Embedded and Ambient Systems, Selected Papers},
      year = {2008},
      pages = {61-68},
      address = {Budapest, B{\'a}thori u. 16, H-1064},
      publisher = {John von Neumann Computer Society},
      note = {ISBN 978-963-8431-98-1},
    }					
    Lőrincz, A. & Szirtes, G. Representation Theory Meets Anatomy: Factor Learning in the Hippocampal Formation 2008 Connectionist Models of Behaviour and Cognition II, 11th Neural Computation and Psychology Workshop, 2008   inproceedings neuro, HC, ARMA
    Abstract: In this paper we argue that computational issues like complexity, memory requirements and training time impose strong constraints on learning in any goal-oriented system. Along these constraints we derive a particular architecture that learns representations for optimizing plans e.g., trajectory planning. To comply with biological constraints as well, the resulting encoding mechanism is translated into a connectionist network. We argue that the goal-oriented framework implies distinct representations of place and direction in the hippocampal formation responsible for spatial navigation in mammals.
    BibTeX:
    @inproceedings{lorincz08representation,
      author = {A. L{\H{o}}rincz and G. Szirtes},
      title = {Representation Theory Meets Anatomy: Factor Learning in the Hippocampal Formation},
      booktitle = {Connectionist Models of Behaviour and Cognition {II}, 11th Neural Computation and Psychology Workshop, 2008},
      year = {2008},
      editor = {J. Mayor and N. Ruh and K. Punklett},
      volume = {18},
      series = {Progress in Neural Processing},
      pages = {253-264},
      address = {Oxford, United Kingdom},
      publisher = {World Scientific Publishing},
    }					
    Lőrincz, A., Palotai, Zs. & Szirtes, G. Spike-based cross-entropy method for reconstruction 2008 Neurocomputing   article neuro, ANN
    Abstract: Most neural optimization algorithms use either gradient tuning methods or complicated recurrent dynamics that may lead to suboptimal solutions or require huge number of iterations. Here we propose a framework based on the cross-entropy method (CEM). CEM is an efficient global optimization technique, but it requires batch access to many samples. We transcribed CEM to an online form and embedded it into a reconstruction network that finds optimal representations in a robust way as demonstrated by computer simulations. We argue that this framework allows for neural implementation and suggests a novel computational role for spikes in real neuronal systems.
    BibTeX:
    @article{lorincz08spike,
      author = {A. L{\H{o}}rincz and {\Zs}. Palotai and G. Szirtes},
      title = {Spike-based cross-entropy method for reconstruction},
      journal = {Neurocomputing},
      year = {2008},
      volume = {71},
      pages = {3635-3639},
    }					
    Palotai, Zs. & Lőrincz, A. Parallel and Adaptive Signal Processing 2008 Patent application   misc
    Abstract: A method and apparatus for parallel and adaptive signal reconstruction from a multitude of signal measurements. Algorithms and hardware are disclosed to denoise the measured signals, to compress the measured signals, and to reconstruct the signal from fewer measurements than standard state-of-the-art methods require. A parallel hardware design is disclosed in which the methods that are described can be efficiently executed.
    BibTeX:
    @misc{palotai08parallel_patent,
      author = {{\Zs}. Palotai and A. L{\H{o}}rincz},
      title = {Parallel and Adaptive Signal Processing},
      journal = {Patent application},
      year = {2008},
      note = {USPTO No.20090185636},
      url = {http://www.wipo.int/patentscope/search/en/WO2009094357},
    }					
    Póczos, B. & Lőrincz, A. D-optimal Bayesian Interrogation for Parameter and Noise Identification of Recurrent Neural Networks 2008   techreport
    Abstract: We introduce a novel online Bayesian method for the identification of a family of noisy recurrent neural networks (RNNs). We develop Bayesian active learning technique in order to optimize the interrogating stimuli given past experiences. In particular, we consider the unknown parameters as stochastic variables and use the D-optimality principle, also known as 'infomax method', to choose optimal stimuli. We apply a greedy technique to maximize the information gain concerning network parameters at each time step. We also derive the D-optimal estimation of the additive noise that perturbs the dynamical system of the RNN. Our analytical results are approximation-free. The analytic derivation gives rise to attractive quadratic update rules.
    BibTeX:
    @techreport{poczos08D-optimal_TR,
      author = {B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {D-optimal {Bayesian} Interrogation for Parameter and Noise Identification of Recurrent Neural Networks},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2008},
      address = {Budapest},
      url = {http://arxiv.org/abs/0801.1883},
    }					
    Szabó, Z. & Lőrincz, A. Towards Independent Subspace Analysis in Controlled Dynamical Systems 2008 ICA Research Network Workshop (ICARN 2008)   inproceedings ICA, active, ARMA
    Abstract: In this paper we extend Independent Component Analysis (ICA) task to controlled dynamical systems. To our best knowledge this is the first work that considers the control task in this field, which may open the door for extended ICA applications. We treat Independent Subspace Analysis (ISA) task, the multidimensional generalization of ICA. In particular, we consider the identification problem of ARX models, i.e., hidden AutoRegressive dynamical systems subject to eXogenous control inputs. In our case, these ARX models are driven by independent multidimensional noise processes. The goal is the estimation of the hidden variables, that is, the parameters of the system and the driving noise. We aim efficient estimation by choosing suitable control values. For the optimal choice of the control we adapt the D-optimality principle, also known as 'InfoMax method'. To this end, we decouple the problem into a fully observable one and an ISA task. We solve the two problems and join the results to estimate the hidden variables. Numerical examples illustrate the efficiency of our method.
    BibTeX:
    @inproceedings{szabo08towards,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Towards Independent Subspace Analysis in Controlled Dynamical Systems},
      booktitle = {ICA Research Network Workshop (ICARN 2008)},
      year = {2008},
      pages = {9-12},
      month = {25-26~September},
    }					
    Szita, I. & Lőrincz, A. Factored Value Iteration Converges 2008 Acta Cybernetica   article RL
    Abstract: In this paper we propose a novel algorithm, factored value iteration (FVI), for the approximate solution of factored Markov decision processes (fMDPs). The traditional approximate value iteration algorithm is modified in two ways. For one, the least-squares projection operator is modified so that it does not increase max-norm, and thus preserves convergence. The other modification is that we uniformly sample polynomially many samples from the (exponentially large) state space. This way, the complexity of our algorithm becomes polynomial in the size of the fMDP description length. We prove that the algorithm is convergent. We also derive an upper bound on the difference between our approximate solution and the optimal one, and also on the error introduced by sampling. We analyze various projection operators with respect to their computation complexity and their convergence when combined with approximate value iteration.
    BibTeX:
    @article{szita08factored,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Factored Value Iteration Converges},
      journal = {Acta Cybernetica},
      year = {2008},
      volume = {18},
      pages = {615-635},
    }					
    Szita, I. & Lőrincz, A. The Many Faces of Optimism: a Unifying Approach 2008 International Conference on Machine Learning (ICML 2008)   inproceedings RL
    Abstract: The exploration-exploitation dilemma has been an intriguing and unsolved problem within the framework of reinforcement learning. Optimism in the face of uncertainty and model building play central roles in advanced exploration methods. Here, we integrate several concepts and obtain a fast and simple algorithm. We show that the proposed algorithm finds a near-optimal policy in polynomial time, and give experimental evidence that it is robust and efficient compared to its ascendants.
    BibTeX:
    @inproceedings{szita08many,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {The Many Faces of Optimism: a Unifying Approach},
      booktitle = {International Conference on Machine Learning (ICML 2008)},
      year = {2008},
      editor = {Andrew McCallum and Sam Roweis},
      pages = {1048--1055},
      address = {Helsinki, Finland},
      publisher = {Omnipress},
    }					
    Szita, I. & Lőrincz, A. Online variants of the cross-entropy method 2008   techreport
    Abstract: The cross-entropy method [2] is a simple but efficient method for global optimization. In this paper we provide two online variants of the basic CEM, together with a proof of convergence.
    BibTeX:
    @techreport{szita08online_TR,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Online variants of the cross-entropy method},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2008},
      address = {Budapest},
      url = {http://arxiv.org/abs/0801.1988},
    }					
    Bárdosi, Z. Robusztus szemdetektor fejlesztése predikciós módszerek felhasználásával (Develoment of robust eye-detector using predictive methods) 2007 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{bardosi07robusztus,
      author = {Z. B{\'a}rdosi},
      title = {Robusztus szemdetektor fejleszt{\'e}se predikci{\'o}s m{\'o}dszerek felhaszn{\'a}l{\'a}s{\'a}val ({D}eveloment of robust eye-detector using predictive methods)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2007},
      address = {Budapest},
    }					
    Gyenes, V. & Lőrincz, A. Co-learning and the development of communication 2007 International Conference on Artificial Neural Networks (ICANN 2007)   inproceedings EOL, ANN
    Abstract: We investigate the properties of coupled co-learning systems during the emergence of communication. Co-learning systems are more complex than individual learing systems because of being dependent on the learning process of each other, thus risking divergence. We developed a neural network approach and implemented a concept that we call reconstruction principle, which we found adequate for overcoming the instability problem. Experimental simulations were performed to the emergence of both compositional and holistic communication. The results show the compositional communication is favorable when learning performance is considered, however it is more error-prone to differences in the conceptual representations of the individual systems. We show that our architecture enables the adjustment of the differences in the individual representations in case of compositional communication.
    BibTeX:
    @inproceedings{gyenes07co-learning,
      author = {V. Gyenes and A. L{\H{o}}rincz},
      title = {Co-learning and the development of communication},
      booktitle = {International Conference on Artificial Neural Networks (ICANN 2007)},
      year = {2007},
      editor = {J. Marques de S{\'a} et al.},
      volume = {4668},
      series = {Lecture Notes in Computer Science - Part I},
      pages = {827-837},
      address = {Berlin Heidelberg},
      month = {9-13~September},
      publisher = {Springer-Verlag},
    }					
    Gyenes, V. & Lőrincz, A. Language development among co-learning agents 2007 6th IEEE Int. Conf. on Development and Learning   inproceedings EOL, ANN
    Abstract: We investigate the properties of coupled colearning systems during the emergence of communication. Colearning systems are more complex than individual learning systems because of being dependent on the learning process of each other, thus risking divergence. We developed a neural network approach and implemented a concept that we call reconstruction principle, which we found adequate for overcoming the instability problem. Experimental simulations were performed to test the emergence of both compositional and holistic communication. The results show that compositional communication is favorable when learning performance is considered, however it is more error-prone to differences in the conceptual representations of the individual systems. We show that our architecture enables the adjustment of the differences in the individual conceptual representations in case of compositional communication.
    BibTeX:
    @inproceedings{gyenes07language,
      author = {V. Gyenes and A. L{\H{o}}rincz},
      title = {Language development among co-learning agents},
      booktitle = {6th IEEE Int. Conf. on Development and Learning},
      year = {2007},
      address = {London},
      month = {11-13~July},
    }					
    Lőrincz, A., Lázár, K. A. & Palotai, Zs. Efficiency of goal-oriented communicating agents in different graph topologies: A study with Internet crawlers 2007 Physica A   article MAS, IR, web
    Abstract: To what extent does the communication make a goal-oriented community efficient in different topologies? In order to gain insight into this problem, we study the influence of learning method as well as that of the topology of the environment on the communication efficiency of crawlers in quest of novel information in different topics on the Internet. Individual crawlers employ selective learning, function approximation-based reinforcement learning (RL), and their combination. Selective learning, in effect, modifies the starting URL lists of the crawlers, whilst RL alters the URL orderings. Real data have been collected from the web and scale-free worlds, scale-free small world (SFSW), and random world environments (RWEs) have been created by link reorganization. In our previous experiments [Zs. Palotai, Cs. Farkas, A. Lorincz, Is selection optimal in scale-free small worlds?, ComPlexUs 3 (2006) 158-168], the crawlers searched for novel, genuine documents and direct communication was not possible. Herein, our finding is reproduced: selective learning performs the best and RL the worst in SFSW, whereas the combined, i.e., selective learning coupled with RL is the best--by a slight margin--in scale-free worlds. This effect is demonstrated to be more pronounced when the crawlers search for different topic-specific documents: the relative performance of the combined learning algorithm improves in all worlds, i.e., in SFSW, in SFW, and in RWE. If the tasks are more complex and the work sharing is enforced by the environment then the combined learning algorithm becomes at least equal, even superior to both the selective and the RL algorithms in most cases, irrespective of the efficiency of communication. Furthermore, communication improves the performance by a large margin and adaptive communication is advantageous in the majority of the cases.
    BibTeX:
    @article{lorincz07efficiency,
      author = {A. L{\H{o}}rincz and K. A. L{\'a}z{\'a}r and {\Zs}. Palotai},
      title = {Efficiency of goal-oriented communicating agents in different graph topologies: A study with Internet crawlers},
      journal = {Physica A},
      year = {2007},
      volume = {378},
      pages = {127-134},
    }					
    Lőrincz, A., Meretei, A. & Palotai, Zs. Embedded neural prosthesis 2007 Patent application   misc
    BibTeX:
    @misc{lorincz07embedded_patent,
      author = {A. L{\H{o}}rincz and A. Meretei and {\Zs}. Palotai},
      title = {Embedded neural prosthesis},
      journal = {Patent application},
      year = {2007},
      note = {USPTO No. 20070239211},
      url = {http://www.freshpatents.com/},
    }					
    Lőrincz, A., Gyenes, V., Kiszlinger, M. & Szita, I. Mind model seems necessary for the emergence of communication 2007 Neural Information Processing -- Letters and Reviews   article RL, cog, EOL
    Abstract: We consider communication when there is no agreement about symbols and meanings. We treat it within the framework of reinforcement learning. This framework enables us to talk about emotional coupling and to consider the emergence of communication. We apply different reinforcement learning models in our studies and simplify the problem as much as possible. We show that the modelling of the other agent is insufficient in the simplest possible case, unless the intentions can also be modelled. The model of the agent and its intentions enable quick agreements about symbol-meaning association. We show that when both agents assume an 'intention model' about the other agent then the symbol-meaning association process can be spoiled and symbol meaning association may become hard.
    BibTeX:
    @article{lorincz07mind,
      author = {A. L{\H{o}}rincz and V. Gyenes and M. Kiszlinger and I. Szita},
      title = {Mind model seems necessary for the emergence of communication},
      journal = {Neural Information Processing -- Letters and Reviews},
      year = {2007},
      volume = {11},
      pages = {109-121},
    }					
    Lőrincz, A. & Szabó, Z. Neurally Plausible, Non-combinatorial Iterative Independent Process Analysis 2007 Neurocomputing - Letters   article ICA, neuro, AR
    Abstract: It has been shown recently that the identification of mixed hidden independent auto-regressive processes (independent process analysis, IPA), under certain conditions, can be free from combinatorial explosion. The key is that IPA can be reduced (i) to independent subspace analysis and then, via a novel decomposition technique called Separation Theorem, (ii) to independent component analysis. Here, we introduce an iterative scheme and its neural network representation that takes advantage of the reduction method and can accomplish the IPA task. Computer simulation illustrates the working of the algorithm.
    BibTeX:
    @article{lorincz07neurally,
      author = {A. L{\H{o}}rincz and Z. Szab{\'o}},
      title = {Neurally Plausible, Non-combinatorial Iterative Independent Process Analysis},
      journal = {Neurocomputing - Letters},
      year = {2007},
      volume = {70},
      number = {7-9},
      pages = {1569--1573},
      address = {Amsterdam, The Netherlands, The Netherlands},
      publisher = {Elsevier Science Publishers B. V.},
      doi = {http://dx.doi.org/10.1016/j.neucom.2006.10.145},
    }					
    Lőrincz, A., Gilbert, N. & Goolsby, R. Social network analysis: Measuring tools, structures and dynamics (Editorial) 2007 Physica A   article social
    Abstract: This special issue of Physica A presents contributions drawn from papers presented at a conference on Social Network Analysis and Complexity held from July 31 to August 2, 2006 at the Collegium Budapest in Budapest, Hungary. Co-chaired by Andras Lorincz of the Eotvos Lorand University and Nigel Gilbert of the University of Surrey, United Kingdom, the conference brought together scientists and scholars from mathematics, computer science, graph theory, statistical physics, network analysis, sociology, political science, technology and media.
    BibTeX:
    @article{lorincz07social,
      author = {A. L{\H{o}}rincz and N. Gilbert and R. Goolsby},
      title = {Social network analysis: Measuring tools, structures and dynamics (Editorial)},
      journal = {Physica A},
      year = {2007},
      volume = {378},
      pages = {xi-xiii},
    }					
    Lőrincz, A., Meretei, A. & Palotai, Zs. Systems and methods for sensing physiologic parameters of the human body and achieving a therapeutic effect 2007 Patent pending   misc
    BibTeX:
    @misc{lorincz07systems_patent,
      author = {A. L{\H{o}}rincz and A. Meretei and {\Zs}. Palotai},
      title = {Systems and methods for sensing physiologic parameters of the human body and achieving a therapeutic effect},
      journal = {Patent pending},
      year = {2007},
      note = {USPTO No. 200700435918},
      url = {http://www.freshpatents.com/},
    }					
    Palotai, Zs. Distributed survivable pipeline computation and communication 2007 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{palotai07distributed,
      author = {{\Zs}. Palotai},
      title = {Distributed survivable pipeline computation and communication},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2007},
      address = {Budapest},
    }					
    Póczos, B., Szabó, Z., Kiszlinger, M. & Lőrincz, A. Independent Process Analysis without A Priori Dimensional Information 2007 Independent Component Analysis and Blind Signal Separation (ICA 2007)   inproceedings ICA, AR
    Abstract: Recently, several algorithms have been proposed for independent subspace analysis where hidden variables are i.i.d. processes. We show that these methods can be extended to certain AR, MA, ARMA and ARIMA tasks. Central to our paper is that we introduce a cascade of algorithms, which aims to solve these tasks without previous knowledge about the number and the dimensions of the hidden processes. Our claim is supported by numerical simulations. As an illustrative application where the dimensions of the hidden variables are unknown, we search for subspaces of facial components.
    BibTeX:
    @inproceedings{poczos07independent,
      author = {B. P{\'o}czos and Z. Szab{\'o} and M. Kiszlinger and A. L{\H{o}}rincz},
      title = {Independent Process Analysis without A Priori Dimensional Information},
      booktitle = {Independent Component Analysis and Blind Signal Separation (ICA 2007)},
      year = {2007},
      editor = {M.E. Davies et al.},
      volume = {4666},
      series = {Lecture Notes in Computer Science},
      pages = {252-259},
      address = {Berlin Heidelberg},
      month = {9-12~September},
      publisher = {Springer-Verlag},
      doi = {http://dx.doi.org/10.1007/978-3-540-74494-8_32},
    }					
    Póczos, B., Szabó, Z., Kiszlinger, M. & Lőrincz, A. Independent Process Analysis without A Priori Dimensional Information 2007   techreport
    Abstract: Recently, several algorithms have been proposed for independent subspace analysis where hidden variables are i.i.d. processes. We show that these methods can be extended to certain AR, MA, ARMA and ARIMA tasks. Central to our paper is that we introduce a cascade of algorithms, which aims to solve these tasks without previous knowledge about the number and the dimensions of the hidden processes. Our claim is supported by numerical simulations. As a particular application, we search for subspaces of facial components.
    BibTeX:
    @techreport{poczos07independent_TR,
      author = {B. P{\'o}czos and Z. Szab{\'o} and M. Kiszlinger and A. L{\H{o}}rincz},
      title = {Independent Process Analysis without A Priori Dimensional Information},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2007},
      address = {Budapest},
      url = {http://arxiv.org/abs/math/0703612},
    }					
    Szabó, Z. & Lőrincz, A. Independent Subspace Analysis can Cope with the `Curse of Dimensionality' 2007 Acta Cybernetica   article ICA
    Abstract: We search for hidden independent components, in particular we consider the independent subspace analysis (ISA) task. Earlier ISA procedures assume that the dimensions of the components are known. Here we show a method that enables the non-combinatorial estimation of the components. We make use of a decomposition principle called the ISA separation theorem. According to this separation theorem the ISA task can be reduced to the independent component analysis (ICA) task that assumes one-dimensional components and then to a grouping procedure that collects the respective non-independent elements into independent groups. We show that non-combinatorial grouping is feasible by means of the non-linear f-correlation matrices between the estimated components.
    BibTeX:
    @article{szabo07independent,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Independent Subspace Analysis can Cope with the `Curse of Dimensionality'},
      journal = {Acta Cybernetica},
      year = {2007},
      volume = {18},
      pages = {213-221},
    }					
    Szabó, Z. & Lőrincz, A. Multilayer Kerceptron 2007 Journal of Applied Mathematics   article ANN
    Abstract: Multilayer Perceptrons (MLP) are formulated within Support Vector Machine (SVM) framework by constructing multilayer networks of SVMs. The coupled approximation scheme can take advantage of generalization capabilities of the SVM and the combinatory feature of the hidden layer of MLP. The network, the Multilayer Kerceptron (MLK) assumes its own backpropagation procedure that we shall derive here. Tuning rule will be provided for quadratic cost function, with regularization capability as well. A further appealing property of our approach is that by the aid of the so called kernel trick the MLK computations can be performed in the dual space.
    BibTeX:
    @article{szabo07multilayer,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Multilayer Kerceptron},
      journal = {Journal of Applied Mathematics},
      year = {2007},
      volume = {24},
      pages = {209-222},
    }					
    Szabó, A. Önszervező, elosztott algoritmusok Smart Dust eszközökhöz (Self-organizing distributed algorithms for Smart Dust devices) 2007 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{szabo07onszervezo,
      author = {A. Szab{\'o}},
      title = {{\"O}nszervez{\H{o}}, elosztott algoritmusok {Smart Dust} eszk{\"o}z{\"o}kh{\"o}z ({S}elf-organizing distributed algorithms for Smart Dust devices)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2007},
      address = {Budapest},
    }					
    Szabó, Z., Póczos, B., Szirtes, G. & Lőrincz, A. Post Nonlinear Independent Subspace Analysis 2007 International Conference on Artificial Neural Networks (ICANN 2007)   inproceedings ICA
    Abstract: In this paper a generalization of Post Nonlinear Independent Component Analysis (PNL-ICA) to Post Nonlinear Independent Subspace Analysis (PNL-ISA) is presented. In this framework sources to be identified can be multidimensional as well. For this generalization we prove a separability theorem: the ambiguities of this problem are essentially the same as for the linear Independent Subspace Analysis (ISA). By applying this result we derive an algorithm using the mirror structure of the mixing system. Numerical simulations are presented to illustrate the efficiency of the algorithm.
    BibTeX:
    @inproceedings{szabo07post,
      author = {Z. Szab{\'o} and B. P{\'o}czos and G. Szirtes and A. L{\H{o}}rincz},
      title = {Post Nonlinear Independent Subspace Analysis},
      booktitle = {International Conference on Artificial Neural Networks (ICANN 2007)},
      year = {2007},
      editor = {J. Marques de S{\'a} et al.},
      volume = {4668},
      series = {Lecture Notes in Computer Science - Part I},
      pages = {677-686},
      address = {Berlin Heidelberg},
      month = {9-13~September},
      publisher = {Springer-Verlag},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Undercomplete Blind Subspace Deconvolution via Linear Prediction 2007 European Conference on Machine Learning (ECML 2007)   inproceedings ICA, MA
    Abstract: We present a novel solution technique for the blind subspace deconvolution (BSSD) problem, where temporal convolution of multidimensional hidden independent components is observed and the task is to uncover the hidden components using the observation only. We carry out this task for the undercomplete case (uBSSD): we reduce the original uBSSD task via linear prediction to independent subspace analysis (ISA), which we can solve. As it has been shown recently, applying temporal concatenation can also reduce uBSSD to ISA, but the associated ISA problem can easily become 'high dimensional' [1]. The new reduction method circumvents this dimensionality problem. We perform detailed studies on the efficiency of the proposed technique by means of numerical simulations. We have found several advantages: our method can achieve high quality estimations for smaller number of samples and it can cope with deeper temporal convolutions.
    BibTeX:
    @inproceedings{szabo07undercomplete_LPA,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Undercomplete Blind Subspace Deconvolution via Linear Prediction},
      booktitle = {European Conference on Machine Learning (ECML 2007)},
      year = {2007},
      editor = {Joost N. Kok et al.},
      volume = {4701},
      series = {Lecture Notes in Artificial Intelligence},
      pages = {740-747},
      address = {Berlin Heidelberg},
      month = {17-21~September},
      publisher = {Springer-Verlag},
      doi = {http://dx.doi.org/10.1007/978-3-540-74958-5_75},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Undercomplete Blind Subspace Deconvolution 2007 Journal of Machine Learning Research   article ICA, MA
    Abstract: We introduce the blind subspace deconvolution (BSSD) problem, which is the extension of both the blind source deconvolution (BSD) and the independent subspace analysis (ISA) tasks. We examine the case of the undercomplete BSSD (uBSSD). Applying temporal concatenation we reduce this problem to ISA. The associated 'high dimensional' ISA problem can be handled by a recent technique called joint f-decorrelation (JFD). Similar decorrelation methods have been used previously for kernel independent component analysis (kernel-ICA). More precisely, the kernel canonical correlation (KCCA) technique is a member of this family, and, as is shown in this paper, the kernel generalized variance (KGV) method can also be seen as a decorrelation method in the feature space. These kernel based algorithms will be adapted to the ISA task. In the numerical examples, we (i)examine how efficiently the emerging higher dimensional ISA tasks can be tackled, and (ii) explore the working and advantages of the derived kernel-ISA methods.
    BibTeX:
    @article{szabo07undercomplete_TCC,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Undercomplete Blind Subspace Deconvolution},
      journal = {Journal of Machine Learning Research},
      year = {2007},
      volume = {8},
      pages = {1063-1095},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Undercomplete Blind Subspace Deconvolution 2007   techreport
    Abstract: We introduce the blind subspace deconvolution (BSSD) problem, which is the extension of both the blind source deconvolution (BSD) and the independent subspace analysis (ISA) tasks. We examine the case of the undercomplete BSSD (uBSSD). Applying temporal concatenation we reduce this problem to ISA. The associated 'high dimensional' ISA problem can be handled by a recent technique called joint f-decorrelation (JFD). Similar decorrelation methods have been used previously for kernel independent component analysis (kernel-ICA). More precisely, the kernel canonical correlation (KCCA) technique is a member of this family, and, as is shown in this paper, the kernel generalized variance (KGV) method can also be seen as a decorrelation method in the feature space. These kernel based algorithms will be adapted to the ISA task. In the numerical examples, we (i) examine how efficiently the emerging higher dimensional ISA tasks can be tackled, and (ii) explore the working and advantages of the derived kernel-ISA methods.
    BibTeX:
    @techreport{szabo07undercomplete_TCC_TR,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Undercomplete Blind Subspace Deconvolution},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2007},
      address = {Budapest},
      url = {http://arxiv.org/abs/math/0701210},
    }					
    Szita, I. & Lőrincz, A. Learning to Play Using Low-Complexity Rule-Based Policies: Illustrations through Ms. Pac-Man 2007 Journal of Artificial Intelligence Research   article RL
    Abstract: In this article we propose a method that can deal with certain combinatorial reinforcement learning tasks. We demonstrate the approach in the popular Ms. Pac-Man game. We define a set of high-level observation and action modules, from which rule-based policies are constructed automatically. In these policies, actions are temporally extended, and may work concurrently. The policy of the agent is encoded by a compact decision list. The components of the list are selected from a large pool of rules, which can be either hand-crafted or generated automatically. A suitable selection of rules is learnt by the cross-entropy method, a recent global optimization algorithm that fits our framework smoothly. Cross-entropy-optimized policies perform better than our hand-crafted policy, and reach the score of average human players. We argue that learning is successful mainly because (i) policies may apply concurrent actions and thus the policy space is sufficiently rich, (ii) the search is biased towards low-complexity policies and therefore, solutions with a compact description can be found quickly if they exist.
    BibTeX:
    @article{szita07learning,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Learning to Play Using Low-Complexity Rule-Based Policies: Illustrations through {Ms. Pac-Man}},
      journal = {Journal of Artificial Intelligence Research},
      year = {2007},
      volume = {30},
      pages = {659-684},
    }					
    Takács, B. & Lőrincz, A. Simple conditions for forming triangular grids 2007 Neurocomputing   article neuro, HC
    Abstract: We have used simple learning rules to study how firing maps containing triangular grids--as found in in vivo experiments--can be developed by Hebbian means in realistic robotic simulations. We started from typical non-local postrhinal neuronal responses. We found that anti-Hebbian weight pruning can develop triangular grids under certain conditions. Experimental evidences and the present study suggest that within this model, whitening is a bottom-up process, whereas weight pruning and possibly the non-linear extension of whitening to bottom-up information maximization are guided by top-down influences that reorganize entorhinal responses. We connect our model to the computational model of the entorhinal-hippocampal region of Lorincz and Buzsaki. In the joined model, the hippocampus is the origin of response reorganization. The joined model may provide insights for memory reorganization guided by hippocampal supervision.
    BibTeX:
    @article{takacs07simple,
      author = {B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Simple conditions for forming triangular grids},
      journal = {Neurocomputing},
      year = {2007},
      volume = {70},
      pages = {1741-1747},
    }					
    Gilbert, N., den Besten, M., Bontovics, Á., Craenen, B. G. W., Divina, F., Eiben, A. E., Griffioen, R., Hévízi, Gy., Lőrincz, A., Paechter, B., Schuster, S., Schut, M. C., Tzolov, C., Vogt, P. & Yang, L. Emerging artificial societies through learning 2006 Journal of Artificial Societies and Social Simulation   article social
    Abstract: The NewTies project is implementing a simulation in which societies of agents are expected to develop autonomously as a result of individual, population and social learning. These societies are expected to be able to solve environmental challenges by acting collectively. The challenges are intended to be analogous to those faced by early, simple, small-scale human societies. This report on work in progress outlines the major features of the system as it is currently conceived within the project, including the design of the agents, the environment, the mechanism for the evolution of language and the peer-to-peer infrastructure on which the simulation runs.
    BibTeX:
    @article{gilbert06emerging,
      author = {N. Gilbert and M. den Besten and {\'A}. Bontovics and B. G. W. Craenen and F. Divina and A. E. Eiben and R. Griffioen and {\Gy}. H{\'e}v{\'\i}zi and A. L{\H{o}}rincz and B. Paechter and S. Schuster and M. C. Schut and C. Tzolov and P. Vogt and L. Yang},
      title = {Emerging artificial societies through learning},
      journal = {Journal of Artificial Societies and Social Simulation},
      year = {2006},
      volume = {9},
      url = {http://jasss.soc.surrey.ac.uk/9/2/9.html},
    }					
    Hajnal, M. A. & Lőrincz, A. Critical Echo State Networks 2006 International Conference on Artificial Neural Networks (ICANN 2006)   inproceedings ANN, RNN
    Abstract: We are interested in the optimization of the recurrent connection structure of Echo State Networks (ESNs), because their topology can strongly influence performance. We study ESN predictive capacity by numerical simulations on Mackey-Glass time series, and find that a particular small subset of ESNs is much better than ordinary ESNs provided that the topology of the recurrent feedback connections satisfies certain conditions. We argue that the small subset separates two large sets of ESNs and this separation can be characterized in terms of phase transitions. With regard to the criticality of this phase transition, we introduce the notion of Critical Echo State Networks (CESN). We discuss why CESNs perform better than other ESNs.
    BibTeX:
    @inproceedings{hajnal06critical,
      author = {M. A. Hajnal and A. L{\H{o}}rincz},
      title = {Critical Echo State Networks},
      booktitle = {International Conference on Artificial Neural Networks (ICANN 2006)},
      year = {2006},
      volume = {4131},
      series = {Lecture Notes in Computer Science},
      pages = {658-667},
    }					
    Hajnal, M. A. Folyamatok előrejelzése nemlineáris rekurrens neuronhálókkal; kritikus hálók (Process prediction using non-linear recurrent neural networks; critical networks) 2006 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{hajnal06folyamatok,
      author = {M. A. Hajnal},
      title = {Folyamatok el{\H{o}}rejelz{\'e}se nemline{\'a}ris rekurrens neuronh{\'a}l{\'o}kkal; kritikus h{\'a}l{\'o}k ({P}rocess prediction using non-linear recurrent neural networks; critical networks)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
    }					
    Lőrincz, A., Gyenes, V., Kiszlinger, M. & Szita, I. Mind model seems necessary for the emergence of communication 2006   techreport
    Abstract: We consider communication when there is no agreement about symbols and meanings. We treat it within the framework of reinforcement learning. We apply different reinforcement learning models in our studies and simplify the problem as much as possible. We show that the modelling of the other agent is insufficient in the simplest possible case, unless the intentions can also be modelled. The model of the agent and its intentions enable quick agreements about symbol-meaning association. We show that when both agents assume an 'intention model' about the other agent then the symbol-meaning association process can be spoiled and symbol meaning association may become hard.
    BibTeX:
    @techreport{lorincz06mind_TR,
      author = {A. L{\H{o}}rincz and V. Gyenes and M. Kiszlinger and I. Szita},
      title = {Mind model seems necessary for the emergence of communication},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
      url = {http://arxiv.org/abs/q-bio/0611012},
    }					
    Palotai, Zs., Mandusitz, S. & Lőrincz, A. Computer study of the evolution of 'news foragers' on the Internet 2006 Swarm Intelligence and Data Mining   inproceedings MAS, IR, web
    Abstract: We populated a huge scale-free portion of Internet environment with news foragers. They evolved by a simple internal selective algorithm: selection concerned the memory components, being finite in size and containing the list of most promising supplies. Foragers received reward for locating not yet found news and crawled by using value estimation. Foragers were allowed to multiply if they passed a given productivity threshold. A particular property of this community is that there is no direct interaction (here, communication) amongst foragers that allowed us to study compartmentalization, assumed to be important for scalability, in a very clear form. Experiments were conducted with our novel scalable Alife architecture. These experiments had two particular features. The first feature concerned the environment: a scale-free world was studied as the space of evolutionary algorithms. The choice of this environment was due to its generality in mother nature. The other feature of the experiments concerned the fitness. Fitness was not predetermined by us, but it was implicitly determined by the unknown, unpredictable environment that sustained the community and by the evolution of the competitive individuals. We found that the Alife community achieved fast compartmentalization.
    BibTeX:
    @inproceedings{palotai06computer,
      author = {{\Zs}. Palotai and S. Mandusitz and A. L{\H{o}}rincz},
      title = {Computer study of the evolution of 'news foragers' on the {Internet}},
      booktitle = {Swarm Intelligence and Data Mining},
      year = {2006},
      editor = {A. Abraham and C. Grosan and V. Ramos},
      volume = {34},
      series = {Springer SCI Series},
      pages = {203-220},
      address = {Berlin, Germany},
      publisher = {Springer},
    }					
    Palotai, Zs., Farkas, Cs. & Lőrincz, A. Is selection optimal for scale-free small worlds? 2006 ComPlexUs   article MAS, IR
    Abstract: The `no free lunch theorem' claims that for the set of all problems no algorithm performs better than random search and, thus, selection can be advantageous only on a limited set of problems. In this paper we investigate how the topological structure of the environment influences algorithmic efficiency. We study the performance of algorithms, using selective learning, reinforcement learning, and their combinations, in random, scale-free, and scale-free small world (SFSW) environments. The learning problem is to search for novel, not-yet-found information. We ran our experiments on a large news site and on its downloaded portion. Controlled experiments were performed on this downloaded portion: we modified the topology, but preserved the publication time of the news. Our empirical results show that the selective learning is the most efficient in SFSW topology. In non-small world topologies, however, the combination of the selective and reinforcement learning algorithms performs the best.
    BibTeX:
    @article{palotai06is,
      author = {{\Zs}. Palotai and {\Cs}. Farkas and A. L{\H{o}}rincz},
      title = {Is selection optimal for scale-free small worlds?},
      journal = {ComPlexUs},
      year = {2006},
      volume = {3},
      pages = {158-168},
    }					
    Póczos, B. Függetlenaltér-analizis (Independent Subspace Analysis) 2006 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{poczos06fuggetlenalter,
      author = {B. P{\'o}czos},
      title = {F{\"u}ggetlenalt{\'e}r-anal{\'\i}zis ({I}ndependent Subspace Analysis)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
    }					
    Póczos, B. & Lőrincz, A. Non-combinatorial estimation of independent autoregressive sources 2006 Neurocomputing   article ICA, AR
    Abstract: Identification of mixed independent subspaces is thought to suffer from combinatorial explosion of two kinds: the minimization of mutual information between the estimated subspaces and the search for the optimal number and dimensions of the subspaces. Here we show that independent autoregressive process analysis, under certain conditions, can avoid this problem using a two-phase estimation process. We illustrate the solution by computer demonstration.
    BibTeX:
    @article{poczos06non-combinatorial,
      author = {B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Non-combinatorial estimation of independent autoregressive sources},
      journal = {Neurocomputing},
      year = {2006},
      volume = {69},
      pages = {2416-2419},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Cross-Entropy Optimization for Independent Process Analysis 2006 Independent Component Analysis and Blind Signal Separation   inproceedings ICA, AR
    Abstract: We treat the problem of searching for hidden multi-dimensional independent auto-regressive processes. First, we transform the problem to Independent Subspace Analysis (ISA). Our main contribution concerns ISA. We show that under certain conditions, ISA is equivalent to a combinatorial optimization problem. For the solution of this optimization we apply the cross-entropy method. Numerical simulations indicate that the cross-entropy method can provide considerable improvements over other state-of-the-art methods.
    BibTeX:
    @inproceedings{szabo06cross,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Cross-Entropy Optimization for Independent Process Analysis},
      booktitle = {Independent Component Analysis and Blind Signal Separation},
      year = {2006},
      editor = {Justinian Rosca and Deniz Erdogmus and Jos{\'e} C. Pr{\'\i}ncipe and Simon Haykin},
      volume = {3889},
      series = {Lecture Notes in Computer Science},
      pages = {909--916},
      month = {5-8~March},
      publisher = {Springer},
      isbn = {3-540-32630-8},
    }					
    Szabó, Z. & Lőrincz, A. Epsilon-Sparse Representations: Generalized sparse approximation and the equivalent family of SVM tasks 2006 Acta Cybernetica   article ANN
    Abstract: Relation between a family of generalized Support Vector Machine (SVM) problems and the novel epsilon-sparse representation is provided. In defining epsilon-sparse representations, we use a natural generalization of the classical epsilon-insensitive cost function for vectors. The insensitive parameter of the SVM problem is transformed into component-wise insensitivity and thus overall sparsification is replaced by component-wise sparsification. The connection between these two problems is built through the generalized Moore-Penrose inverse of the Gram matrix associated to the kernel.
    BibTeX:
    @article{szabo06epsilon,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Epsilon-Sparse Representations: Generalized sparse approximation and the equivalent family of {SVM} tasks},
      journal = {Acta Cybernetica},
      year = {2006},
      volume = {17},
      number = {3},
      pages = {605--614},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Separation Theorem for K-Independent Subspace Analysis with Sufficient Conditions 2006   techreport
    Abstract: Here, a Separation Theorem about K-Independent Subspace Analysis (K real or complex), a generalization of K-Independent Component Analysis (KICA) is proven. According to the theorem, KISA estimation can be executed in two steps under certain conditions. In the first step, 1-dimensional KICA estimation is executed. In the second step, optimal permutation of the KICA elements is searched for. We present sufficient conditions for the KISA Separation Theorem. Namely, we shall show that (i) spherically symmetric sources (both for real and complex cases), as well as (ii) real 2-dimensional sources invariant to 90 degree rotation, among others, satisfy the conditions of the theorem.
    BibTeX:
    @techreport{szabo06Kseparation_TR,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Separation Theorem for $\mathbb{K}$-Independent Subspace Analysis with Sufficient Conditions},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
      url = {http://arxiv.org/abs/math/0608100},
    }					
    Szabó, Z. & Lőrincz, A. Real and Complex Independent Subspace Analysis by Generalized Variance 2006 ICA Research Network International Workshop (ICARN 2006)   inproceedings ICA
    Abstract: Here, we address the problem of Independent Subspace Analysis (ISA). We develop a technique that (i) builds upon joint decorrelation for a set of functions, (ii) can be related to kernel based techniques, (iii) can be interpreted as a self-adjusting, self-grouping neural network solution, (iv) can be used both for real and for complex problems, and (v) can be a first step towards large scale problems. Our numerical examples extend to a few 100 dimensional ISA tasks.
    BibTeX:
    @inproceedings{szabo06real,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Real and Complex Independent Subspace Analysis by Generalized Variance},
      booktitle = {{ICA} Research Network International Workshop (ICARN 2006)},
      year = {2006},
      pages = {85--88},
      month = {18-19~September},
    }					
    Szabó, Z. & Lőrincz, A. Real and Complex Independent Subspace Analysis by Generalized Variance 2006   techreport
    Abstract: Here, we address the problem of Independent Subspace Analysis (ISA). We develop a technique that (i) builds upon joint decorrelation for a set of functions, (ii) can be related to kernel based techniques, (iii) can be interpreted as a self-adjusting, self-grouping neural network solution, (iv) can be used both for real and for complex problems, and (v) can be a first step towards large scale problems. Our numerical examples extend to a few 100 dimensional ISA tasks.
    BibTeX:
    @techreport{szabo06real_TR,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Real and Complex Independent Subspace Analysis by Generalized Variance},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
      url = {http://arxiv.org/abs/math/0610438},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Separation Theorem for Independent Subspace Analysis with Sufficient Conditions 2006   techreport
    Abstract: Here, a separation theorem about Independent Subspace Analysis (ISA), a generalization of Independent Component Analysis (ICA) is proven. According to the theorem, ISA estimation can be executed in two steps under certain conditions. In the first step, 1-dimensional ICA estimation is executed. In the second step, optimal permutation of the ICA elements is searched for. We present sufficient conditions for the ISA Separation Theorem. Namely, we shall show that (i) elliptically symmetric sources, (ii) 2-dimensional sources invariant to 90 degree rotation, among others, satisfy the conditions of the theorem.
    BibTeX:
    @techreport{szabo06separation_TR,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Separation Theorem for Independent Subspace Analysis with Sufficient Conditions},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
      url = {http://arxiv.org/abs/math/0603535},
    }					
    Szendrő, B. Környezeti intelligencia adatgyűjtés és adatelemzés (Data collection and data analysis for ambient intelligence) 2006 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{szendro06kornyezeti,
      author = {B. Szendr{\H{o}}},
      title = {K{\"o}rnyezeti intelligencia adatgy{\H{u}}jt{\'e}s {\'e}s adatelemz{\'e}s ({D}ata collection and data analysis for ambient intelligence)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
    }					
    Szita, I. & Lőrincz, A. Learning Tetris using the noisy cross-entropy method 2006 Neural Computation   article RL
    Abstract: The cross-entropy method is an efficient and general optimization algorithm. However, its applicability in reinforcement learning (RL) seems to be limited because it often converges to suboptimal policies. We apply noise for preventing early convergence of the cross-entropy method, using Tetris, a computer game, for demonstration. The resulting policy outperforms previous RL algorithms by almost two orders ofmagnitude.
    BibTeX:
    @article{szita06learning,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Learning {Tetris} using the noisy cross-entropy method},
      journal = {Neural Computation},
      year = {2006},
      volume = {18},
      pages = {2936-2941},
    }					
    Szita, I. & Lőrincz, A. Low-complexity modular policies: learning to play Pac-Man and a new framework beyond MDPs 2006   techreport
    Abstract: In this paper we propose a method that learns to play Pac-Man. We define a set of high-level observation and action modules. Actions are temporally extended, and multiple action modules may be in effect concurrently. A decision of the agent is represented as a rule-based policy. For learning, we apply the cross-entropy method, a recent global optimization algorithm. The learned policies reached better score than the hand-crafted policy, and neared the score of average human players. We argue that learning is successful mainly because (i) the policy space includes the combination of individual actions and thus it is sufficiently rich, (ii) the search is biased towards low-complexity policies and low complexity solutions can be found quickly if they exist. Based on these principles, we formulate a new theoretical framework, which can be found in the Appendix as supporting materia.
    BibTeX:
    @techreport{szita06low_TR,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Low-complexity modular policies: learning to play {Pac-Man} and a new framework beyond {MDP}s},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0610170},
    }					
    Szita, I. Outside the Wall: Directions for Extending Reinforcement Learning to Complex Domains 2006 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{szita06outside,
      author = {I. Szita},
      title = {Outside the Wall: Directions for Extending Reinforcement Learning to Complex Domains},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
    }					
    Szita, I. & Lőrincz, A. PIRANHA: Policy Iteration for Recurrent Artificial neural Networks with Hidden Activities 2006 Neurocomputing   article RNN, RL
    Abstract: It is an intriguing task to develop efficient connectionist representations for learning long time series. Recurrent neural networks have great promises here. We model the learning task as a minimization problem of a nonlinear least-squares cost function, that takes into account both one-step and multi-step prediction errors. The special structure of the cost function is constructed to build a bridge to reinforcement learning. We exploit this connection and derive a convergent, policy iteration-based algorithm, and show that RNN training can be made to fit the reinforcement learning framework in a natural fashion. The relevance of this connection is discussed. We also present experimental results, which demonstrate the appealing properties of the unique parameter structure prescribed by reinforcement learning. Experiments cover both sequence learning and long-term prediction.
    BibTeX:
    @article{szita06piranha,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {{PIRANHA}: Policy Iteration for Recurrent Artificial neural Networks with Hidden Activities},
      journal = {Neurocomputing},
      year = {2006},
      volume = {70},
      pages = {577-591},
    }					
    Szita, I., Gyenes, V. & Lőrincz, A. Reinforcement learning with Echo State Networks 2006 International Conference on Artificial Neural Networks (ICANN 2006)   inproceedings RL, RNN
    Abstract: Function approximators are often used in reinforcement learning tasks with large or continuous state spaces. Artificial neural networks, among them recurrent neural networks are popular function approximators, especially in tasks where some kind of of memory is needed, like in real-world partially observable scenarios. However, convergence guarantees for such methods are rarely available. Here, we propose a method using a class of novel RNNs, the echo state networks. Proof of convergence to a bounded region is provided for k-order Markov decision processes. Runs on POMDPs were performed to test and illustrate the working of the architecture.
    BibTeX:
    @inproceedings{szita06reinforcement,
      author = {I. Szita and V. Gyenes and A. L{\H{o}}rincz},
      title = {Reinforcement learning with Echo State Networks},
      booktitle = {International Conference on Artificial Neural Networks (ICANN 2006)},
      year = {2006},
      volume = {4131},
      series = {Lecture Notes in Computer Science},
      pages = {830-839},
    }					
    Takács, B. & Lőrincz, A. Independent component analysis forms place cells in realistic robot simulations 2006 Neurocomputing   article ICA, HC
    Abstract: It has been argued that the processing of sensory information in the entorhinal-hippocampal loop involves independent component analysis (ICA) on temporally concatenated inputs. Here, we demonstrate that ICA in a realistic robot simulation on a U-shaped track forms place fields similar to those found in rat experiments in vivo.
    BibTeX:
    @article{takacs06independent,
      author = {B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Independent component analysis forms place cells in realistic robot simulations},
      journal = {Neurocomputing},
      year = {2006},
      volume = {69},
      pages = {1249-1252},
    }					
    Takács, B. Komponensek keresése a megerősitéses tanulásban (Finding components in reinforcement learning) 2006 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{takacs06komponensek,
      author = {B. Tak{\'a}cs},
      title = {Komponensek keres{\'e}se a meger{\H{o}}s{\'\i}t{\'e}ses tanul{\'a}sban ({F}inding components in reinforcement learning)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2006},
      address = {Budapest},
    }					
    Ziegler, G., Farkas, Cs. & Lőrincz, A. A framework for anonymous but accountable self-organizing communities 2006 Information and Software Technology   article social
    Abstract: In this paper we propose a novel architecture and approach to provide accountability for Web communities that require a high-level of privacy. A two-layered privacy protection architecture is proposed, that supports (i) registration of participants and enforcement of community rules, called internal accountability, and (ii) rule-based interaction with real world organizations, called external accountability. Our security protocols build upon community-based trust and limit the exposure of private data on trusted third parties. The two-layered architecture protects the mappings between real users and their virtual identities, and among the virtual users, while guaranteeing internal and external accountability. We target Web communities that are dynamic and self-organizing, i.e. roles and contributions of participants may change over time. The proposed concepts and protocols are implemented in our SyllabNet project that supports anonymous course evaluations by university students.
    BibTeX:
    @article{ziegler06framework,
      author = {G. Ziegler and {\Cs}. Farkas and A. L{\H{o}}rincz},
      title = {A framework for anonymous but accountable self-organizing communities},
      journal = {Information and Software Technology},
      year = {2006},
      volume = {48},
      pages = {726-744},
    }					
    Eiben, A. E., Gilbert, N., Lőrincz, A., Paechter, B. & Vogt, P. The New Ties project: 3 dimensions of adaptivity and 3 dimensions of complexity scale-up 2005 European Conference on Complex Systems (ECCS, poster)   inproceedings social, complexity
    BibTeX:
    @inproceedings{eiben05new-ties,
      author = {A. E. Eiben and N. Gilbert and A. L{\H{o}}rincz and B. Paechter and P. Vogt},
      title = {The {New Ties} project: 3 dimensions of adaptivity and 3 dimensions of complexity scale-up},
      booktitle = {European Conference on Complex Systems (ECCS, poster)},
      year = {2005},
    }					
    Gábor, B., Gyenes, V. & Lőrincz, A. A corpus-based neural net method for explaining unknown words by WordNet senses 2005 Lecture Notes in Artificial Intelligence   article NLP, ANN
    Abstract: This paper introduces an unsupervised algorithm that collects senses contained in WordNet to explain words, whose meaning is unknown, but plenty of documents are available that contain the word in that unknown sense. Based on the widely accepted idea that the meaning of a word is characterized by its context, a neural network architecture was designed to reconstruct the meaning of the unknown word. The connections of the network were derived from word co-occurrences and word-sense statistics. The method was tested on 80 TOEFL synonym questions, from which 63 questions were answered correctly. This is comparable to other methods tested on the same questions, but using a larger corpus or richer lexical database. The approach was found robust against details of the architecture.
    BibTeX:
    @article{gabor05corpus,
      author = {B. G{\'a}bor and V. Gyenes and A. L{\H{o}}rincz},
      title = {A corpus-based neural net method for explaining unknown words by {WordNet} senses},
      journal = {Lecture Notes in Artificial Intelligence},
      year = {2005},
      volume = {3721},
      pages = {470-477},
    }					
    Gerőfi, B. Hangegér - hang és beszédfelismerés (Voicemouse) 2005 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{gerofi05hangeger,
      author = {B. Ger{\H{o}}fi},
      title = {Hangeg{\'e}r - hang {\'e}s besz{\'e}dfelismer{\'e}s ({V}oicemouse)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2005},
      address = {Budapest},
    }					
    Griffioen, A. R., Bontovics, Á., Eiben, A. E., Hévízi, Gy. & Lőrincz, A. Investigating complexity with the New Ties agent 2005 European Conference on Complex Systems (ECCS, poster)   inproceedings social, complexity
    BibTeX:
    @inproceedings{griffioen05investigating,
      author = {A. R. Griffioen and {\'A}. Bontovics and A. E. Eiben and {\Gy}. H{\'e}v{\'\i}zi and A. L{\H{o}}rincz},
      title = {Investigating complexity with the {New Ties} agent},
      booktitle = {European Conference on Complex Systems (ECCS, poster)},
      year = {2005},
    }					
    Griffioen, A. R., Schut, M. C., Eiben, A. G., Bontovics, Á., Hévízi, Gy. & Lőrincz, A. NEW TIES Agent 2005 Proc. of the Socially Inspired Computing Joint Symposium   inproceedings social
    BibTeX:
    @inproceedings{griffionen05new,
      author = {A. R. Griffioen and M. C. Schut and A. G. Eiben and {\'A}. Bontovics and {\Gy}. H{\'e}v{\'\i}zi and A. L{\H{o}}rincz},
      title = {{NEW TIES} Agent},
      booktitle = {Proc. of the Socially Inspired Computing Joint Symposium},
      year = {2005},
      pages = {72-79},
      address = {Hatfield UK},
      month = {12-14~April},
      note = {AISB'05 Convention},
    }					
    Gyenes, V. Intelligens adatbányászat (Intelligent datamining) 2005 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{gyenes05intelligens,
      author = {V. Gyenes},
      title = {Intelligens adatb{\'a}ny{\'a}szat ({I}ntelligent datamining)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2005},
      address = {Budapest},
    }					
    Hévízi, Gy., Gerőfi, B., Szendrő, B. & Lőrincz, A. Assisting robotic personal agent and cooperating alternative input devices for severely disabled children 2005 Lecture Notes in Artificial Intelligence   article AAC, MEMS
    Abstract: A multi-component cooperating system have been designed for severely disabled children having various disabilities. Different input tools have been developed to exploit possible 'outputs', e.g., head motion or leg motion. Specific software tools serve to convert such 'outputs' in different computer aided tasks. Extendable software enables configurable networking. Robotic personal agent helps the communication.
    BibTeX:
    @article{hevizi05assisting,
      author = {{\Gy}. H{\'e}v{\'\i}zi and B. Ger{\H{o}}fi and B. Szendr{\H{o}} and A. L{\H{o}}rincz},
      title = {Assisting robotic personal agent and cooperating alternative input devices for severely disabled children},
      journal = {Lecture Notes in Artificial Intelligence},
      year = {2005},
      volume = {3690},
      pages = {591-594},
    }					
    Kiszlinger, M. Szemdetektor (Eyedetector) 2005 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{kiszlinger05szemdetektor,
      author = {M. Kiszlinger},
      title = {Szemdetektor ({E}yedetector)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2005},
      address = {Budapest},
    }					
    Lőrincz, A. Attentional filtering in neocortical areas: A top-down model 2005 Neurocomputing   article neuro
    Abstract: Two-comparator-based rate code models -- a control architecture and the corresponding reconstruction network -- are merged. The role of reconstruction is information maximization and bottom-up (BU) noise filtering, whereas top-down control 'paves the way' for context compliant BU information that, together, we identify with attentional filtering. Falsifying prediction of the model has gained experimental support.
    BibTeX:
    @article{lorincz05attentional,
      author = {A. L{\H{o}}rincz},
      title = {Attentional filtering in neocortical areas: A top-down model},
      journal = {Neurocomputing},
      year = {2005},
      volume = {65},
      pages = {817-823},
    }					
    Lőrincz, A., Hévízi, Gy., Palotai, Zs. & Szendrő, B. Embedded body sensor network for persons with special communication needs to control and to interact with the world -- DEMO 2005 Proceedings of the International Workshop on Wearable and Implantable Body Sensor Networks   inproceedings AAC, MEMS
    Abstract: There is an ongoing project at the Eotvos Lorand University. We have been developing tools for severely handicapped, non-speaking but speech understanding children. Main components of the project are (i) the development of special communication tools including a controllable pet, Aibo, (ii) the development of machine learning techniques for situational optimization, and (iii) the development of Body Sensor Network (BSN) to form ambient intelligence.
    BibTeX:
    @inproceedings{lorincz05embedded,
      author = {A. L{\H{o}}rincz and {\Gy}. H{\'e}v{\'\i}zi and {\Zs}. Palotai and B. Szendr{\H{o}}},
      title = {Embedded body sensor network for persons with special communication needs to control and to interact with the world -- {DEMO}},
      booktitle = {Proceedings of the International Workshop on Wearable and Implantable Body Sensor Networks},
      year = {2005},
      pages = {117},
      address = {Imperial College, London},
      month = {12-13~April},
      note = {IEE London, ISBN 0-86341-505-9},
    }					
    Lőrincz, A. Independent Kalman-filter model of the entorhinal-hippocampal loop 2005 Society for Neuroscience Meeting   inproceedings HC, neuro, ICA, AR
    BibTeX:
    @inproceedings{lorincz05independent,
      author = {A. L{\H{o}}rincz},
      title = {Independent {Kalman}-filter model of the entorhinal-hippocampal loop},
      booktitle = {Society for Neuroscience Meeting},
      year = {2005},
      month = {November},
    }					
    Palotai, Zs., Gábor, B. & Lőrincz, A. Adaptive highlighting of links to assist surfing on the Internet 2005 International Journal of Information Technology & Decision Making   article ANN, IR, NLP, web
    BibTeX:
    @article{palotai05adaptive,
      author = {{\Zs}. Palotai and B. G{\'a}bor and A. L{\H{o}}rincz},
      title = {Adaptive highlighting of links to assist surfing on the {Internet}},
      journal = {International Journal of Information Technology \& Decision Making},
      year = {2005},
      volume = {4},
      pages = {117-139},
    }					
    Palotai, Zs., Farkas, Cs. & Lőrincz, A. Selection in scale-free small world 2005 Lecture Notes in Artificial Intelligence   article MAS, IR, web
    Abstract: In this paper we compare our selection based learning algorithm with the reinforcement learning algorithm in Web crawlers. The task of the crawlers is to find new information on the Web. We performed simulations based on data collected from the Web. The collected portion of the Web is typical and exhibits scale-free small world (SFSW) structure. We have found that on this SFSW, the weblog update algorithm performs better than the reinforcement learning algorithm. It finds the new information faster than the reinforcement learning algorithm and has better new information/all submitted documents ratio.
    BibTeX:
    @article{palotai05selection,
      author = {{\Zs}. Palotai and {\Cs}. Farkas and A. L{\H{o}}rincz},
      title = {Selection in scale-free small world},
      journal = {Lecture Notes in Artificial Intelligence},
      year = {2005},
      volume = {3690},
      pages = {579-582},
    }					
    Palotai, Zs., Farkas, Cs. & Lőrincz, A. Selection in Scale-Free Small World 2005   techreport
    Abstract: In this paper we compare the performance characteristics of our selection based learning algorithm for Web crawlers with the characteristics of the reinforcement learning algorithm. The task of the crawlers is to find new information on the Web. The selection algorithm, called weblog update, modifies the starting URL lists of our crawlers based on the found URLs containing new information. The reinforcement learning algorithm modifies the URL orderings of the crawlers based on the received reinforcements for submitted documents. We performed simulations based on data collected from the Web. The collected portion of the Web is typical and exhibits scale-free small world (SFSW) structure. We have found that on this SFSW, the weblog update algorithm performs better than the reinforcement learning algorithm. It finds the new information faster than the reinforcement learning algorithm and has better new information/all submitted documents ratio. We believe that the advantages of the selection algorithm over reinforcement learning algorithm is due to the small world property of the Web.
    BibTeX:
    @techreport{palotai05selection_TR,
      author = {{\Zs}. Palotai and {\Cs}. Farkas and A. L{\H{o}}rincz},
      title = {Selection in Scale-Free Small World},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2005},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0504063},
    }					
    Póczos, B. & Lőrincz, A. Independent subspace analysis using geodesic spanning trees 2005 International Conference on Machine Learing (ICML'05)   inproceedings ICA
    Abstract: A novel algorithm for performing Independent Subspace Analysis, the estimation of hidden independent subspaces is introduced. This task is a generalization of Independent Component Analysis. The algorithm works by estimating the multi-dimensional differential entropy. The estimation utilizes minimal geodesic spanning trees matched to the sampling points. Numerical studies include (i) illustrative examples, (ii) generalization of the cocktail-party problem to songs played by bands, and (iii) an example on mixed independent subspaces, where subspaces have dependent sources, which are pairwise independent.
    BibTeX:
    @inproceedings{poczos05independent_geodesic,
      author = {B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Independent subspace analysis using geodesic spanning trees},
      booktitle = {International Conference on Machine Learing (ICML'05)},
      year = {2005},
      pages = {673-680},
    }					
    Póczos, B. & Lőrincz, A. Independent subspace analysis using k-nearest neighborhood distances 2005 Lecture Notes in Computer Science   article ICA
    Abstract: A novel algorithm called independent subspace analysis (ISA) is introduced to estimate independent subspaces. The algorithm solves the ISA problem by estimating multi-dimensional differential entropies. Two variants are examined, both of them utilize distances between the k-nearest neighbors of the sample points. Numerical simulations demonstrate the usefullness of the algorithms.
    BibTeX:
    @article{poczos05independent_k-nearest,
      author = {B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Independent subspace analysis using k-nearest neighborhood distances},
      journal = {Lecture Notes in Computer Science},
      year = {2005},
      volume = {3697},
      pages = {163-168},
    }					
    Póczos, B., Takács, B. & Lőrincz, A. Independent subspace analysis on innovations 2005 Lecture Notes in Artificial Intelligence   article ICA, AR
    Abstract: Independent subspace analysis (ISA) that deals with multidimensional independent sources, is a generalization of independent component analysis (ICA). However, all known ISA algorithms may become ineffective when the sources possess temporal structure. The innovation process instead of the original mixtures has been proposed to solve ICA problems with temporal dependencies. Here we show that this strategy can be applied to ISA as well. We demonstrate the idea on a mixture of 3D processes and also on a mixture of facial pictures used as two-dimensional deterministic sources. ISA on innovations was able to find the original subspaces, while plain ISA was not.
    BibTeX:
    @article{poczos05innovation,
      author = {B. P{\'o}czos and B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Independent subspace analysis on innovations},
      journal = {Lecture Notes in Artificial Intelligence},
      year = {2005},
      volume = {3720},
      pages = {698-706},
    }					
    Szabó, Z., Póczos, B. & Lőrincz, A. Separation Theorem for Independent Subspace Analysis 2005   techreport
    Abstract: Here, a separation theorem about Independent Subspace Analysis (ISA), a generalization of Independent Component Analysis (ICA) is proven. According to the theorem, ISA estimation can be executed in two steps under certain conditions. In the first step, 1-dimensional ICA estimation is executed. In the second step, optimal permutation of the ICA elements is searched for. We shall show that elliptically symmetric sources, among others, satisfy the conditions of the theorem.
    BibTeX:
    @techreport{szabo05separation_TR,
      author = {Z. Szab{\'o} and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Separation Theorem for Independent Subspace Analysis},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2005},
      address = {Budapest},
      note = {(\url{http://nipg.inf.elte.hu/szzoli/publications/szabo05separation_TR.pdf})},
    }					
    Szirtes, G., Póczos, B. & Lőrincz, A. Neural Kalman-filter 2005 Neurocomputing   article ANN, neuro
    Abstract: Anticipating future events is a crucial function of the central nervous system and can be modelled by Kalman filter-like mechanisms, which are optimal for predicting linear dynamical systems. Connectionist representation of such mechanisms with Hebbian learning rules has not yet been derived. We show that the recursive prediction error method offers a solution that can be mapped onto the entorhinal-hippocampal loop in a biologically plausible way. Model predictions are provided.
    BibTeX:
    @article{szirtes05neural,
      author = {G. Szirtes and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Neural {Kalman}-filter},
      journal = {Neurocomputing},
      year = {2005},
      volume = {65},
      pages = {349-355},
    }					
    Tóth, F. Orrdetektor -- Viola-Jones detektorok használata gyors orrdetektor használatához (Nose detector) 2005 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{toth05orrdetektor,
      author = {F. T{\'o}th},
      title = {Orrdetektor -- {Viola-Jones} detektorok haszn{\'a}lata gyors orrdetektor haszn{\'a}lat{\'a}hoz ({N}ose detector)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2005},
      address = {Budapest},
    }					
    Bakos, N. Tanulási folyamat számitógéppel történő kölcsönhatásban (Learning during interaction with computer) 2004 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{bakos04tanulasi,
      author = {N. Bakos},
      title = {Tanul{\'a}si folyamat sz{\'a}m{\'\i}t{\'o}g{\'e}ppel t{\"o}rt{\'e}n{\H{o}} k{\"o}lcs{\"o}nhat{\'a}sban ({L}earning during interaction with computer)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Biczó, M. Párhuzamos számolások optimalizálása megerősitéses tanulás segitségével: Tanulmány fejmozgással vezérelhető kurzor esetére (Optimization of parallel processing using reinforcement learning: Study for the case of a cursor controlled by head motion) 2004 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{biczo04parhuzamos,
      author = {M. Bicz{\'o}},
      title = {P{\'a}rhuzamos sz{\'a}mol{\'a}sok optimaliz{\'a}l{\'a}sa meger{\H{o}}s{\'\i}t{\'e}ses tanul{\'a}s seg{\'\i}ts{\'e}g{\'e}vel: Tanulm{\'a}ny fejmozg{\'a}ssal vez{\'e}relhet{\H{o}} kurzor eset{\'e}re ({O}ptimization of parallel processing using reinforcement learning: Study for the case of a cursor controlled by head motion)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Bontovics, Á. Hálózaton barangoló célorientált témafelügyelő horda fejlődése (Development of goal-oriented topic monitoring internet crawler horde) 2004 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{bontovics04halozaton,
      author = {{\'A}. Bontovics},
      title = {H{\'a}l{\'o}zaton barangol{\'o} c{\'e}lorient{\'a}lt t{\'e}mafel{\"u}gyel{\H{o}} horda fejl{\H{o}}d{\'e}se ({D}evelopment of goal-oriented topic monitoring internet crawler horde)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Feldhoffer, G. Dallamkövetés és osztályozás népdalokban (Tune tracking and classification in folksongs) 2004 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{feldhoffer04dallamkovetes,
      author = {G. Feldhoffer},
      title = {Dallamk{\"o}vet{\'e}s {\'e}s oszt{\'a}lyoz{\'a}s n{\'e}pdalokban ({T}une tracking and classification in folksongs)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Gábor, B. Adaptiv linkkiemelő internetes böngészéshez (Adaptive link highlighter for websurfing) 2004 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{gabor04adaptiv,
      author = {B. G{\'a}bor},
      title = {Adapt{\'\i}v linkkiemel{\H{o}} internetes b{\"o}ng{\'e}sz{\'e}shez ({A}daptive link highlighter for websurfing)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Gábor, B., Palotai, Zs. & Lőrincz, A. Value estimation based computer-assisted data mining for surfing the Internet 2004 Int. Joint Conf. on Neural Networks 2004   inproceedings RL, IR, NLP, web
    Abstract: Gathering of novel information from the WWW constitutes a real challenge for artificial intelligence (AI) methods. Large search engines do not offer a satisfactory solution, their indexing cycle is long and they may offer a huge amount of documents. An AI-based link-highlighting procedure designed to assist surfing is studied here. It makes use of (i) 'experts', i.e. pretrained classifiers, forming the long-term memory of the system, (ii) relative values of experts and value estimation of documents based on recent choices of the users. Value estimation adapts fast and forms the short-term memory of the system. All experiments show that surfing based filtering can efficiently highlight 10.20% of the documents in about 5 steps, or less.
    BibTeX:
    @inproceedings{gabor04value,
      author = {B. G{\'a}bor and {\Zs}. Palotai and A. L{\H{o}}rincz},
      title = {Value estimation based computer-assisted data mining for surfing the {Internet}},
      booktitle = {Int. Joint Conf. on Neural Networks 2004},
      year = {2004},
      note = {IEEE Catalog Number: 04CH37541C, Paper No. 1035},
    }					
    Hévízi, Gy., Biczó, M., Póczos, B., Szabó, Z., Takács, B. & Lőrincz, A. Hidden Markov model finds behavioral patterns of users working with a headmouse driven writing tool 2004 Int. Joint Conf. on Neural Networks 2004   inproceedings AAC, ANN
    Abstract: We studied user behaviors when the cursor is directed by a head in a simple control task. We used an intelligent writing tool called Dasher. Hidden Markov models (HMMs) were applied to separate behavioral patterns. We found that a similar It is argued that the recognition of general application specific behavioral patterns should he of help for adaptive human-computer interfaces.
    BibTeX:
    @inproceedings{hevizi04hidden,
      author = {{\Gy}. H{\'e}v{\'\i}zi and M. Bicz{\'o} and B. P{\'o}czos and Z. Szab{\'o} and B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Hidden {Markov} model finds behavioral patterns of users working with a headmouse driven writing tool},
      booktitle = {Int. Joint Conf. on Neural Networks 2004},
      year = {2004},
      note = {IEEE Catalog Number: 04CH37541C, Paper No. 1268},
    }					
    Hévízi, Gy., Marcinkovics, T. & Lőrincz, A. Improving recognition accuracy on structured documents by learning structural patterns 2004 Pattern Analysis and Applications   article ANN, IR
    Abstract: In this paper, we present a probabilistic method that can improve the efficiency of document classification when applied to structured documents. The analysis of the structure of a document is the starting point of document classification. Our method is designed to augment other classification schemes and complement pre-filtering information extraction procedures to reduce uncertainties. To this end, a probabilistic distribution on the structure of XML documents is introduced. We show how to parameterise existing learning methods to describe the structure distribution efficiently. The learned distribution is then used to predict the classes of unseen documents. Novelty detection making use of the structure-based distribution function is also discussed. Demonstration on model documents and on Internet XML documents are presented.
    BibTeX:
    @article{hevizi04improving,
      author = {{\Gy}. H{\'e}v{\'\i}zi and T. Marcinkovics and A. L{\H{o}}rincz},
      title = {Improving recognition accuracy on structured documents by learning structural patterns},
      journal = {Pattern Analysis and Applications},
      year = {2004},
      volume = {7},
      pages = {66-76},
    }					
    Lőrincz, A., Gábor, B., Mandusitz, S. & Palotai, Zs. Bottom-up clustering and top-down shattering of scale-free environments for information fusion 2004 Information Fusion   inproceedings IR
    Abstract: We consider information fusion an 'active service', which aims to adapt the presentation of the information to the user. Our work concerns the Internet, a scale-free small world graph, with the tasks being the evaluation of documents, novelty detection and collecting novel documents of 'high value' for the sake of the user. This procedure calls for user-computer interaction. To this end, four algorithms have been designed and are under testing in various Internet environments. The weblog algorithm utilizes competitive value-estimating agents and shatters the Internet domain. Bottom-up clustering develops tree-structured cluster hierarchies and alleviates navigation. Keyword extraction chooses the best keywords that match subsets of the clusters. Link highlighting makes use of user reinforcement, ranks Internet documents and closes the loop: It provides feedback to the weblog algorithm to improve value estimation and the shattering of the domain. Details about the algorithms are provided.
    BibTeX:
    @inproceedings{lorincz04bottom-up,
      author = {A. L{\H{o}}rincz and B. G{\'a}bor and S. Mandusitz and {\Zs}. Palotai},
      title = {Bottom-up clustering and top-down shattering of scale-free environments for information fusion},
      booktitle = {Information Fusion},
      year = {2004},
      address = {Stockholm, Sweden},
      month = {28~June~--~1~July},
    }					
    Lőrincz, A. Intelligent encoding and economical communication in the visual stream 2004   techreport
    Abstract: The theory of computational complexity is used to underpin a recent model of neocortical sensory processing. We argue that encoding into reconstruction networks is appealing for communicating agents using Hebbian learning and working on hard combinatorial problems, which are easy to verify. Computational definition of the concept of intelligence is provided. Simulations illustrate the idea.
    BibTeX:
    @techreport{lorincz04intelligent_TR,
      author = {A. L{\H{o}}rincz},
      title = {Intelligent encoding and economical communication in the visual stream},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
      url = {http://arxiv.org/abs/q-bio/0403022},
    }					
    Palotai, Zs., Mandusitz, S. & Lőrincz, A. Distributed novel news mining from the Internet with an evolutionary news forager community 2004 Int. Joint Conf. on Neural Networks 2004   inproceedings MAS, IR, web
    Abstract: We populated a huge scale-free portion of Internet environment with news forazers. They evolved hy a simple internal selective algorithm: selection concerned the memory components, being finite in size and containing the list of most promising supplies. Foragers received reward for locating not yet found news and crawled by using value estimation. Foragers were allowed to multiply if they passed a given productivity threshold. A particular property of this community is that there is no direct interaction (here, communication) amongst foragers. It is found that, still, fast compartmentalization, i.e., fast division of work can be achieved.
    BibTeX:
    @inproceedings{palotai04distributed,
      author = {{\Zs}. Palotai and S. Mandusitz and A. L{\H{o}}rincz},
      title = {Distributed novel news mining from the Internet with an evolutionary news forager community},
      booktitle = {Int. Joint Conf. on Neural Networks 2004},
      year = {2004},
      note = {IEEE Catalog Number: 04CH37541C, Paper No. 1095},
    }					
    Palotai, Zs., Szirtes, G. & Lőrincz, A. Emerging evolutionary features in noise driven STDP networks? 2004 Int. Joint Conf. on Neural Networks 2004   inproceedings ANN, neuro
    Abstract: In this paper we study the emergent structure of networks in which spike-timing dependent synaptic plasticity is induced only by external random noise. we show that noise driven Hebbian networks are able to develop a broad range o[ network structures including scale-free small-world networks. The development of such network structures may provide an explanation of the role of noise and its interplay with Hebbian plasticity. We also argue that this model can be seen as a unification of the famous Watts-Strogatz and preferential attachment models of small-world and scale-free nets. Our results may support Edelman's idea on that the development of central nervous system may have evolutionary components.
    BibTeX:
    @inproceedings{palotai04emerging,
      author = {{\Zs}. Palotai and G. Szirtes and A. L{\H{o}}rincz},
      title = {Emerging evolutionary features in noise driven {STDP} networks?},
      booktitle = {Int. Joint Conf. on Neural Networks 2004},
      year = {2004},
      note = {IEEE Catalog Number: 04CH37541C, Paper No. 1119},
    }					
    Szabó, Z. & Lőrincz, A.  L1 regularization is better than  L2 for learning and predicting chaotic systems 2004   techreport
    Abstract: Emergent behaviors are in the focus of recent research interest. It is then of considerable importance to investigate what optimizations suit the learning and prediction of chaotic systems, the putative candidates for emergence. We have compared L1 and L2 regularizations on predicting chaotic time series using linear recurrent neural networks. The internal representation and the weights of the networks were optimized in a unifying framework. Computational tests on different problems indicate considerable advantages for the L1 regularization: It had considerably better learning time and better interpolating capabilities. We shall argue that optimization viewed as a maximum likelihood estimation justifies our results, because L1 regularization fits heavy-tailed distributions -- an apparently general feature of emergent systems -- better.
    BibTeX:
    @techreport{szabo04l1_TR,
      author = {Z. Szab{\'o} and A. L{\H{o}}rincz},
      title = {{$L_1$} regularization is better than {$L_2$} for learning and predicting chaotic systems},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0410015},
    }					
    Szatmáry, B., Póczos, B. & Lőrincz, A. Competitive spiking and indirect entropy minimization of rate code: Efficient search for hidden components 2004 Journal of Physiology (Paris)   article neuro, ANN
    Abstract: Our motivation, which originates from the psychological and physiological evidences of component-based representations in the brain, is to find neural methods that can efficiently search for structures. Here, an architecture made of coupled parallel working reconstruction subnetworks is presented. Each subnetwork utilizes non-negativity constraint on the generative weights and on the internal representation. 'Spikes' are generated within subnetworks via winner take all mechanism. Memory components are modified in order to directly minimize the reconstruction error and to indirectly minimize the entropy of the spike rate distribution, via a combination of a stochastic gradient search and a novel tuning method. This tuning dynamically changes the learning rate: the higher the entropy of the spike rate, the higher the learning rate of the gradient search in the subnetworks. This method effectively reduces the search space and increases the escape probability from high entropy local minima. We demonstrate that one subnetwork can develop localized and oriented components. Coupled networks can discover and sort components into the subnetworks; a problem subject to combinatorial explosion. Synergy between spike code and rate code is discussed.
    BibTeX:
    @article{szatmary04competitive,
      author = {B. Szatm{\'a}ry and B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Competitive spiking and indirect entropy minimization of rate code: Efficient search for hidden components},
      journal = {Journal of Physiology (Paris)},
      year = {2004},
      volume = {98},
      pages = {407-416},
    }					
    Szatmáry, B. Neurális tanulás rekonstrukciós hálózatokkal (Neural learning using reconstruction networks) 2004 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{szatmary04neuralis,
      author = {B. Szatm{\'a}ry},
      title = {Neur{\'a}lis tanul{\'a}s rekonstrukci{\'o}s h{\'a}l{\'o}zatokkal (Neural learning using reconstruction networks)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Szirtes, G. A hippokampális formáció funkcionális modellezése (Modelling the function of the hippocampal formation) 2004 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{szirtes04hippokampalis,
      author = {G. Szirtes},
      title = {A hippokamp{\'a}lis form{\'a}ci{\'o} funkcion{\'a}lis modellez{\'e}se ({M}odelling the function of the hippocampal formation)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Szita, I. & Lőrincz, A. Applying Policy Iteration for Training Recurrent Neural Networks 2004   techreport
    Abstract: Recurrent neural networks are often used for learning time-series data. Based on a few assumptions we model this learning task as a minimization problem of a nonlinear least-squares cost function. The special structure of the cost function allows us to build a connection to reinforcement learning. We exploit this connection and derive a convergent, policy iteration-based algorithm. Furthermore, we argue that RNN training can be fit naturally into the reinforcement learning framework.
    BibTeX:
    @techreport{szita04applying_TR,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Applying Policy Iteration for Training Recurrent Neural Networks},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0410004},
    }					
    Szita, I. & Lőrincz, A. Kalman filter control embedded into the reinforcement learning framework 2004 Neural Computation   article ANN, RL
    Abstract: There is a growing interest in using Kalman filter models in brain modeling. The question arises whether Kalman filter models can be used on-line not only for estimation but for control. The usual method of optimal control of Kalman filter makes use of off-line backward recursion, which is not satisfactory for this purpose. Here, it is shown that a slight modification of the linear-quadratic-gaussian Kalman filter model allows the on-line estimation of optimal control by using reinforcement learning and overcomes this difficulty. Moreover, the emerging learning rule for value estimation exhibits a Hebbian form, which is weighted by the error of the value estimation.
    BibTeX:
    @article{szita04kalman,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Kalman filter control embedded into the reinforcement learning framework},
      journal = {Neural Computation},
      year = {2004},
      volume = {16},
      pages = {491-499},
    }					
    Szita, I. & Lőrincz, A. Simple algorithm for recurrent neural networks that can learn sequence completion 2004 Int. Joint Conf. on Neural Networks 2004   inproceedings RNN
    Abstract: We can memorize long sequences like melodies or poems and it is intriguing to develop efficient connectionist representations for this problem. Recurrent neural networks have been proved to offer a reasonable approach here. We start from a few axiomatic assumptions and provide a simple mathematical framework that encapsulates the problem. A gradient-descent based algorithm is derived in this framework. Demonstrations on a benchmark problem show the applicability of our approach.
    BibTeX:
    @inproceedings{szita04simple,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Simple algorithm for recurrent neural networks that can learn sequence completion},
      booktitle = {Int. Joint Conf. on Neural Networks 2004},
      year = {2004},
      note = {IEEE Catalog Number: 04CH37541C, Paper No. 1101},
    }					
    Takács, B., Szita, I. & Lőrincz, A. An algorithm for finding reliably schedulable plans 2004 Int. Joint Conf. on Neural Networks 2004   inproceedings RL
    Abstract: For interacting agents in time-critical applications, learning whether a subtask can be scheduled reliably is an important issue. The identification of subproblems of this nature may promote e.g. planning, scheduling and segmenting in Markov decision processes. We define a subtask to be schedulable if its execution time has a small variance. We present an algorithm for finding such subtasks.
    BibTeX:
    @inproceedings{takacs04algorithm,
      author = {B. Tak{\'a}cs and I. Szita and A. L{\H{o}}rincz},
      title = {An algorithm for finding reliably schedulable plans},
      booktitle = {Int. Joint Conf. on Neural Networks 2004},
      year = {2004},
      note = {IEEE Catalog Number: 04CH37541C, Paper No. 1098},
    }					
    Ziegler, G. Some problems and its solutions of networked communication and interworking 2004 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{ziegler04some,
      author = {G. Ziegler},
      title = {Some problems and its solutions of networked communication and interworking},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2004},
      address = {Budapest},
    }					
    Lőrincz, A. Comparation based bottom-up and top-down filtering model of the hippocampus and its environment 2003   techreport
    Abstract: Two rate code models -- a reconstruction network model and a control model -- of the hippocampal-entorhinal loop are merged. The hippocampal-entorhinal loop plays a double role in the unified model, it is part of a reconstruction network and a controller, too. This double role turns the bottom-up information flow into top-down control like signals. The role of bottom-up filtering is information maximization, noise filtering, temporal integration and prediction, whereas the role of top-down filtering is emphasizing, i.e., highlighting or 'paving of the way' as well as context based pattern completion. In the joined model, the control task is performed by cortical areas, whereas reconstruction networks can be found between cortical areas. While the controller is highly non-linear, the reconstruction network is an almost linear architecture, which is optimized for noise estimation and noise filtering. A conjecture of the reconstruction network model -- that the long-term memory of the visual stream is the linear feedback connections between neocortical areas -- is reinforced by the joined model. Falsifying predictions are presented; some of them have recent experimental support. Connections to attention and to awareness are made.
    BibTeX:
    @techreport{lorincz03comparation_TR,
      author = {A. L{\H{o}}rincz},
      title = {Comparation based bottom-up and top-down filtering model of the hippocampus and its environment},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/q-bio/0311030},
    }					
    Lőrincz, A. Controlled hierarchical filtering: Model of neocortical sensory processing 2003   techreport
    Abstract: A model of sensory information processing is presented. The model assumes that learning of internal (hidden) generative models, which can predict the future and evaluate the precision of that prediction, is of central importance for information extraction. Furthermore, the model makes a bridge to goal-oriented systems and builds upon the structural similarity between the architecture of a robust controller and that of the hippocampal entorhinal loop. This generative control architecture is mapped to the neocortex and to the hippocampal entorhinal loop. Implicit memory phenomena; priming and prototype learning are emerging features of the model. Mathematical theorems ensure stability and attractive learning properties of the architecture. Connections to reinforcement learning are also established: both the control network, and the network with a hidden model converge to (near) optimal policy under suitable conditions. Falsifying predictions, including the role of the feedback connections between neocortical areas are made.
    BibTeX:
    @techreport{lorincz03controlled_TR,
      author = {A. L{\H{o}}rincz},
      title = {Controlled hierarchical filtering: Model of neocortical sensory processing},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0308025},
    }					
    Lőrincz, A. & Póczos, B. Cost component analysis 2003 International Journal of Neural Systems   article ANN, ICA
    Abstract: In optimizations the dimension of the problem may severely, sometimes exponentially increase optimization time. Parametric function approximatiors (FAPPs) have been suggested to overcome this problem. Here, a novel FAPP, cost component analysis (CCA) is described. In CCA, the search space is resampled according to the Boltzmann distribution generated by the energy landscape. That is, CCA converts the optimization problem to density estimation. Structure of the induced density is searched by independent component analysis (ICA). The advantage of CCA is that each independent ICA component can be optimized separately. In turn, (i) CCA intends to partition the original problem into subproblems and (ii) separating (partitioning) the original optimization problem into subproblems may serve interpretation. Most importantly, (iii) CCA may give rise to high gains in optimization time. Numerical simulations illustrate the working of the algorithm.
    BibTeX:
    @article{lorincz03cost,
      author = {A. L{\H{o}}rincz and B. P{\'o}czos},
      title = {Cost component analysis},
      journal = {International Journal of Neural Systems},
      year = {2003},
      volume = {13},
      pages = {183-192},
    }					
    Lőrincz, A., Pólik, I. & Szita, I. Event-learning and robust policy heuristics 2003 Cognitive Systems Research   article RL, cog
    Abstract: In this paper we introduce a novel reinforcement learning algorithm called event-learning. The algorithm uses events, ordered pairs of two consecutive states.We define event-value function and we derive learning rules. Combining our method with a well-known robust control method, the SDS algorithm, we introduce Robust Policy Heuristics (RPH). It is shown that RPH, a fast-adapting non-Markovian policy, is particularly useful for coarse models of the environment and could be useful for some partially observed systems. RPH may be of help in alleviating the 'curse of dimensionality' problem. Event-learning and RPH can be used to separate time scales of learning of value functions and adaptation. We argue that the definition of modules is straightforward for event-learning and event-learning makes planning feasible in the RL framework. Computer simulations of a rotational inverted pendulum with coarse discretization are shown to demonstrate the principle.
    BibTeX:
    @article{lorincz03event-learning,
      author = {A. L{\H{o}}rincz and I. P{\'o}lik and I. Szita},
      title = {Event-learning and robust policy heuristics},
      journal = {Cognitive Systems Research},
      year = {2003},
      volume = {4},
      pages = {319-337},
    }					
    Lőrincz, A. Modelling the `homunculus' 2003 NEWS of the European Research Consortium for Informatics and Mathematics (ERCIM NEWS), Special Issue on Cognitive Systems   article cog
    BibTeX:
    @article{lorincz03modelling,
      author = {A. L{\H{o}}rincz},
      title = {Modelling the `homunculus'},
      journal = {NEWS of the European Research Consortium for Informatics and Mathematics (ERCIM NEWS), Special Issue on Cognitive Systems},
      year = {2003},
      volume = {53},
      pages = {21-22},
    }					
    Lőrincz, A. & Szirtes, G. Towards a theory of consciousness: Proposal for the resolution of the homunculus fallacy with predictions 2003   techreport
    Abstract: In this paper we argue that no forms of Turing test are either necessary or sufficient to establish if a machine is conscious or not. Furthermore, from a modeling point of view, the problem is that the Turing test does not really provide testable predictions. We believe that the model structure should explain the function (of consciousness). We argue that the cornerstone of any model on consciousness is to (partly) overcome the obstacle of the homunculus fallacy about the use of representations. In this contribution a possible solution is suggested, which makes use of reflexive architectures. The emerging computational constraints on the proposed architecture have lead to testable predictions on the dynamical behavior of the biological substrate. Interestingly, these predictions are in good agreement with recent experimental observations.
    BibTeX:
    @techreport{lorincz03towards_TR,
      author = {A. L{\H{o}}rincz and G. Szirtes},
      title = {Towards a theory of consciousness: Proposal for the resolution of the homunculus fallacy with predictions},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/nlin/0303042},
    }					
    Mandusitz, S. Gyors információgyűjtés az Interneten versenyző barangolókkal (Fast collection of novel information on the Internet with competing crawlers) 2003 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{mandusitz03gyors,
      author = {S. Mandusitz},
      title = {Gyors inform{\'a}ci{\'o}gy{\H{u}}jt{\'e}s az Interneten versenyz{\H{o}} barangol{\'o}kkal ({F}ast collection of novel information on the Internet with competing crawlers)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
    }					
    Molnár, Gy. Új kulcsszavak és dokumentumok keresése az interneten (Searching for new keywords and documents on the Internet) 2003 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{molnar03uj,
      author = {{\Gy}. Moln{\'a}r},
      title = {{\'U}j kulcsszavak {\'e}s dokumentumok keres{\'e}se az interneten ({S}earching for new keywords and documents on the Internet)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
    }					
    Palotai, Zs., Mandusitz, S. & Lőrincz, A. Centralized reward system gives rise to fast and efficient work sharing for intelligent Internet agents lacking direct communication 2003   techreport
    Abstract: WWW has a scale-free structure where novel information is often difficult to locate. Moreover, Intelligent agents easily get trapped in this structure. Here a novel method is put forth, which turns these traps into information repositories, supplies: We populated an Internet environment with intelligent news foragers. Foraging has its associated cost whereas foragers are rewarded if they detect not yet discovered novel information. The intelligent news foragers crawl by using the estimated long-term cumulated reward, and also have a finite sized memory: the list of most promising supplies. Foragers form an artificial life community: the most successful ones are allowed to multiply, while unsuccessful ones die out. The specific property of this community is that there is no direct communication amongst foragers but the centralized rewarding system. Still, fast division of work is achieved.
    BibTeX:
    @techreport{palotai03centralized_TR,
      author = {{\Zs}. Palotai and S. Mandusitz and A. L{\H{o}}rincz},
      title = {Centralized reward system gives rise to fast and efficient work sharing for intelligent Internet agents lacking direct communication},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0308042},
    }					
    Póczos, B. & Lőrincz, A. Kalman-filtering using local interactions 2003   techreport
    Abstract: There is a growing interest in using Kalman-filter models for brain modelling. In turn, it is of considerable importance to represent Kalman-filter in connectionist forms with local Hebbian learning rules. To our best knowledge, Kalman-filter has not been given such local representation. It seems that the main obstacle is the dynamic adaptation of the Kalman-gain. Here, a connectionist representation is presented, which is derived by means of the recursive prediction error method. We show that this method gives rise to attractive local learning rules and can adapt the Kalman-gain.
    BibTeX:
    @techreport{poczos03kalman_TR,
      author = {B. P{\'o}czos and A. L{\H{o}}rincz},
      title = {Kalman-filtering using local interactions},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0302039},
    }					
    Szabó, Z. Retina alapú mintavételezés arckomponens detektálási feladaton (Retina based sampling in face component recognition) 2003 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{szabo03retina,
      author = {Z. Szab{\'o}},
      title = {Retina alap{\'u} mintav{\'e}telez{\'e}s arckomponens detekt{\'a}l{\'a}si feladaton ({R}etina based sampling in face component recognition)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
    }					
    Szatmáry, B., Szirtes, G., Lőrincz, A., Eggert, J. & Körner, E. Robust hierarchical image representation using non-negative matrix factorization with sparse code shrinkage preprocessing 2003 Pattern Analysis and Application   article ANN
    Abstract: When analysing patterns, our goals are (i) to find structure in the presence of noise, (ii) to decompose the observed structure into sub-components, and (iii) to use the components for pattern completion. Here, a novel loop architecture is introduced to perform these tasks in an unsupervised manner. The architecture combines sparse code shrinkage with non-negative matrix factorisation, and blends their favourable properties: sparse code shrinkage aims to remove Gaussian noise in a robust fashion; non-negative matrix factorisation extracts substructures from the noise filtered inputs. The loop architecture performs robust pattern completion when organised into a two-layered hierarchy. We demonstrate the power of the proposed architecture on the so-called 'bar-problem' and on the FERET facial database.
    BibTeX:
    @article{szatmary03robust,
      author = {B. Szatm{\'a}ry and G. Szirtes and A. L{\H{o}}rincz and J. Eggert and E. K{\"o}rner},
      title = {Robust hierarchical image representation using non-negative matrix factorization with sparse code shrinkage preprocessing},
      journal = {Pattern Analysis and Application},
      year = {2003},
      volume = {6},
      pages = {194-200},
    }					
    Szirtes, G., Palotai, Zs. & Lőrincz, A. Emergence of scale-free properties in Hebbian networks 2003   techreport
    Abstract: The fundamental 'plasticity' of the nervous system (i.e high adaptability at different structural levels) is primarily based on Hebbian learning mechanisms that modify the synaptic connections. The modifications rely on neural activity and assign a special dynamic behavior to the neural networks. Another striking feature of the nervous system is that spike based information transmission, which is supposed to be robust against noise, is noisy in itself: the variance of the spiking of the individual neurons is surprisingly large which may deteriorate the adequate functioning of the Hebbian mechanisms. In this paper we focus on networks in which Hebbian-like adaptation is induced only by external random noise and study spike-timing dependent synaptic plasticity. We show that such 'HebbNets' are able to develop a broad range of network structures, including scale-free small-world networks. The development of such network structures may provide an explanation of the role of noise and its interplay with Hebbian plasticity. We also argue that this model can be seen as a unification of the famous Watts-Strogatz and preferential attachment models of small-world nets.
    BibTeX:
    @techreport{szirtes03emergence_TR,
      author = {G. Szirtes and {\Zs}. Palotai and A. L{\H{o}}rincz},
      title = {Emergence of scale-free properties in {Hebbian} networks},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/nlin/0308013},
    }					
    Szita, I., Takács, B. & Lőrincz, A. Epsilon-MDPs: Learning in varying environments 2003 Journal of Machine Learning Research   article RL
    Abstract: In this paper epsilon-MDP-models are introduced and convergence theorems are proven using the generalized MDP framework of Szepesv�ri and Littman. Using this model family, we show that Q-learning is capable of finding near-optimal policies in varying environments. The potential of this new family of MDP models is illustrated via a reinforcement learning algorithm called event-learning which separates the optimization of decision making from the controller. We show that event-learning augmented bya particular controller, which gives rise to an epsilon-MDP, enables near optimal performance even if considerable and sudden changes may occur in the environment. Illustrations are provided on the two-segment pendulum problem.
    BibTeX:
    @article{szita03epsilon-MDPs,
      author = {I. Szita and B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Epsilon-{MDP}s: Learning in varying environments},
      journal = {Journal of Machine Learning Research},
      year = {2003},
      volume = {3},
      pages = {145-174},
    }					
    Szita, I. & Lőrincz, A. Kalman filter control in the reinforcement learning framework 2003   techreport
    Abstract: There is a growing interest in using Kalman-filter models in brain modelling. In turn, it is of considerable importance to make Kalman-filters amenable for reinforcement learning. In the usual formulation of optimal control it is computed off-line by solving a backward recursion. In this technical note we show that slight modification of the linear-quadratic-Gaussian Kalman-filter model allows the on-line estimation of optimal control and makes the bridge to reinforcement learning. Moreover, the learning rule for value estimation assumes a Hebbian form weighted by the error of the value estimation.
    BibTeX:
    @techreport{szita03kalman_TR,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Kalman filter control in the reinforcement learning framework},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0301007},
    }					
    Szita, I. & Lőrincz, A. Reinforcement Learning with Linear Function Approximation and LQ control Converges 2003   techreport
    Abstract: Reinforcement learning is commonly used with function approximation. However, very few positive results are known about the convergence of function approximation based RL control algorithms. In this paper we show that TD(0) and Sarsa(0) with linear function approximation is convergent for a simple class of problems, where the system is linear and the costs are quadratic (the LQ control problem). Furthermore, we show that for systems with Gaussian noise and non-completely observable states (the LQG problem), the mentioned RL algorithms are still convergent, if they are combined with Kalman filtering.
    BibTeX:
    @techreport{szita03reinforcement_TR,
      author = {I. Szita and A. L{\H{o}}rincz},
      title = {Reinforcement Learning with Linear Function Approximation and {LQ} control Converges},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0306120},
    }					
    Takács, B., Szita, I. & Lőrincz, A. Temporal plannability by variance of the episode length 2003   techreport
    Abstract: Optimization of decision problems in stochastic environments is usually concerned with maximizing the probability of achieving the goal and minimizing the expected episode length. For interacting agents in time-critical applications, learning of the possibility of scheduling of subtasks (events) or the full task is an additional relevant issue. Besides, there exist highly stochastic problems where the actual trajectories show great variety from episode to episode, but completing the task takes almost the same amount of time. The identification of sub-problems of this nature may promote e.g., planning, scheduling and segmenting Markov decision processes. In this work, formulae for the average duration as well as the standard deviation of the duration of events are derived. The emerging Bellman-type equation is a simple extension of Sobel's work (1982). Methods of dynamic programming as well as methods of reinforcement learning can be applied for our extension. Computer demonstration on a toy problem serve to highlight the principle.
    BibTeX:
    @techreport{takacs03temporal_TR,
      author = {B. Tak{\'a}cs and I. Szita and A. L{\H{o}}rincz},
      title = {Temporal plannability by variance of the episode length},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2003},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0301006},
    }					
    Bartalos, M. STAGE -- Bin-packing Függvényapproximátor egy optimalizációs problémához (STAGE - bin-packing: Function approximation for an optimization problem) 2002 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{bartalos02stage,
      author = {M. Bartalos},
      title = {{STAGE} -- Bin-packing F{\"u}ggv{\'e}nyapproxim{\'a}tor egy optimaliz{\'a}ci{\'o}s probl{\'e}m{\'a}hoz ({STAGE} - bin-packing: Function approximation for an optimization problem)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2002},
      address = {Budapest},
    }					
    Farkas, Cs., Ziegler, G., Meretei, A. & Lőrincz, A. A2SOC: Anonymity and accountability in self-organizing electronic communities 2002 ACM Workshop on Privacy in Electronic Society   inproceedings social
    BibTeX:
    @inproceedings{farkas02A2SOC,
      author = {{\Cs}. Farkas and G. Ziegler and A. Meretei and A. L{\H{o}}rincz},
      title = {{A2SOC}: Anonymity and accountability in self-organizing electronic communities},
      booktitle = {ACM Workshop on Privacy in Electronic Society},
      year = {2002},
      pages = {81-91},
      address = {Washington, D.C., USA},
      month = {18-22~November},
    }					
    Hegyes, I. Sztochasztikus dinamikai rendszerek és alkalmazásaik (Stochastic dynamic systems and applications) 2002 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{hegyes02sztochasztikus,
      author = {I. Hegyes},
      title = {Sztochasztikus dinamikai rendszerek {\'e}s alkalmaz{\'a}saik ({S}tochastic dynamic systems and applications)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2002},
      address = {Budapest},
    }					
    Kéri, Sz., Janka, Z., Benedek, Gy., Aszalós, P., Szatmáry, B., Szirtes, G. & Lőrincz, A. Categories, prototypes and memory systems in Alzheimer's disease 2002 Trends in Cognitive Science   article cog, neuro, ANN
    Abstract: Recent studies indicate that category learning is mediated by multiple neuronal systems. It has been shown that patients with marked impairments in executive functions, explicit memory and procedural learning can categorize the exemplars and prototype of a previously trained category. Simple, self-organizing neuronal networks can explain prototype learning and related dysfunctions in Alzheimer's disease, and provide a model of how prototype learning is mediated by circumscribed mechanisms in the visual cortex.
    BibTeX:
    @article{keri02categories,
      author = {{\Sz}. K{\'e}ri and Z. Janka and {\Gy}. Benedek and P. Aszal{\'o}s and B. Szatm{\'a}ry and G. Szirtes and A. L{\H{o}}rincz},
      title = {Categories, prototypes and memory systems in {Alzheimer}'s disease},
      journal = {Trends in Cognitive Science},
      year = {2002},
      pages = {132-136},
    }					
    Kókai, I. & Lőrincz, A. Fast adapting value estimation based hybrid architecture for searching the world-wide web 2002 Applied Soft Computing   article RL, IR, NLP
    Abstract: The slogan that information is power has undergone a slight change. Today, information updating is in the focus of interest. The largest source of information is the world-wide web. Fast search methods are in need for this enormous source. In this paper a hybrid architecture that combines soft support vector classification and reinforcement learning for value estimation is introduced for the evaluation of a link (a document) and its neighboring links (or documents), called the context of a document. The method is motivated by (i) large differences between such contexts on the web, (ii) the facilitation of goal oriented search using context classifiers, and (iii) attractive fast adaptation properties, that could counteract diversity of web environments.We demonstrate that value estimation-based fast adaptation offers considerable improvement over other known search methods.
    BibTeX:
    @article{kokai02fast,
      author = {I. K{\'o}kai and A. L{\H{o}}rincz},
      title = {Fast adapting value estimation based hybrid architecture for searching the world-wide web},
      journal = {Applied Soft Computing},
      year = {2002},
      volume = {2},
      pages = {11-23},
    }					
    Lőrincz, A., Kókai, I. & Meretei, A. Intelligent high-performance crawlers used to reveal topic-specific structure of the WWW 2002 International Journal of Foundations of Computer Science   article IR, NLP, web
    Abstract: The slogan that 'information is power' has undergone a slight change. Today, 'information updating' is in the focus of interest. The largest source of information today is the World Wide Web. Fast search methods are needed to utilize this enormous source of information. In this paper our novel crawler using support vector classification and on-line reinforcement learning is described. We launched crawler searches from different sites, including sites that offer, at best, very limited information about the search subject. This case may correspond to typical searches of non-experts. Results indicate that the considerable performance improvement of our crawler over other known crawlers is due to its on-line adaptation property. We used our crawler to characterize basic topic-specific properties of WWW environments. It was found that topic-specific regions have a broad distribution of valuable documents. Expert sites are excellent starting points, whereas mailing list can form traps for the crawler. These properties of the WWW and the emergence of intelligent 'high-performance' crawlers that monitor and search for novel information together predict a significant increase of communication load on the WWW in the near future.
    BibTeX:
    @article{lorincz02intelligent,
      author = {A. L{\H{o}}rincz and I. K{\'o}kai and A. Meretei},
      title = {Intelligent high-performance crawlers used to reveal topic-specific structure of the {WWW}},
      journal = {International Journal of Foundations of Computer Science},
      year = {2002},
      volume = {13},
      pages = {477-495},
    }					
    Lőrincz, A., Szatmáry, B. & Szirtes, G. Mystery of structure and function of sensory processing areas of the neocortex: A resolution 2002 Journal of Computational Neuroscience   article neuro, HC
    Abstract: Many different neural models have been proposed to account for major characteristics of the memory phenomenon family in primates. However, in spite of the large body of neurophysiological, anatomical and behavioral data, there is no direct evidence for supporting one model while falsifying the others. And yet, we can discriminate models based on their complexity and/or their predictive power. In this paper we present a computational framework with our basic assumption that neural information processing is performed by generative networks. A complex architecture is 'derived' by using information-theoretic principles. We find that our approach seems to uncover possible relations among the functional memory units (declarative and implicit memory) and the process of information encoding in primates. The architecture can also be related to the entorhinal-hippocampal loop. An effort is made to form a prototype of this computational architecture and to map it onto the functional units of the neocortex. This mapping leads us to claim that one may gain a better understanding by considering that anatomical and functional layers of the cortex differ. Philosophical consequences regarding the homunculus fallacy are also considered.
    BibTeX:
    @article{lorincz02mystery,
      author = {A. L{\H{o}}rincz and B. Szatm{\'a}ry and G. Szirtes},
      title = {Mystery of structure and function of sensory processing areas of the neocortex: A resolution},
      journal = {Journal of Computational Neuroscience},
      year = {2002},
      volume = {13},
      pages = {187-205},
    }					
    Lőrincz, A., Póczos, B., Szirtes, G. & Takács, B. Ockham's razor at work: Modeling of the 'homunculus' 2002 Brain and Mind   article cog, ANN
    Abstract: There is a broad consensus about the fundamental role of the hippocampal system (hippocampus and its adjacent areas) in the encoding and retrieval of episodic memories. This paper presents a functional model of this system. Although memory is not a single-unit cognitive function, we took the view that the whole system of the smooth, interrelated memory processes may have a common basis. That is why we follow the Ockham's razor principle and minimize the size or complexity of our model assumption set. The fundamental assumption is the requirement of solving the so called 'homunculus fallacy', which addresses the issue of interpreting the input. Generative autoassociators seem to offer a resolution of the paradox. Learning to represent and to recall information, in these generative networks, imply maximization of information transfer, sparse representation and novelty recognition. A connectionist architecture, which integrates these aspects as model constraints, is derived. Numerical studies demonstrate the novelty recognition and noise filtering properties of the architecture. Finally, we conclude that the derived connectionist architecture can be related to the neurobiological substrate.
    BibTeX:
    @article{lorincz02ockham,
      author = {A. L{\H{o}}rincz and B. P{\'o}czos and G. Szirtes and B. Tak{\'a}cs},
      title = {Ockham's razor at work: Modeling of the 'homunculus'},
      journal = {Brain and Mind},
      year = {2002},
      volume = {3},
      pages = {187-220},
    }					
    Lőrincz, A., Szirtes, G., Takács, B., Biederman, I. & Vogels, R. Relating priming and repetition suppression 2002 International Journal of Neural Systems   article neuro, cog, ANN
    Abstract: We present a prototype of a recently proposed two stage model of the entorhinal-hippocampal loop. Our aim is to form a general computational model of the sensory neocortex. The model -- grounded on pure information theoretic principles -- accounts for the most characteristic features of long-term memory (LTM), performs bottom-up novelty detection, and supports noise filtering. Noise filtering can also serve to correct the temporal ordering of information processing. Surprisingly, as we examine the temporal characteristics of the model, the emergent dynamics can be interpreted as perceptual priming, a fundamental type of implicit memory. In the model's framework, computational results support the hypothesis of a strong correlation between perceptual priming and repetition suppression and this correlation is a direct consequence of the temporal ordering in forming the LTM. We also argue that our prototype offers a relatively simple and coherent explanation of priming and its relation to a general model of information processing by the brain.
    BibTeX:
    @article{lorincz02relating,
      author = {A. L{\H{o}}rincz and G. Szirtes and B. Tak{\'a}cs and I. Biederman and R. Vogels},
      title = {Relating priming and repetition suppression},
      journal = {International Journal of Neural Systems},
      year = {2002},
      volume = {12},
      pages = {187-202},
    }					
    Palotai, Zs., Kandár, T., Mohr, Z., Visegrády, T., Ziegler, G., Arató, P. & Lőrincz, A. Value prediction in HLS allocation problems using intellectual properties 2002 Applied Artificial Intelligence   article HW
    Abstract: A value approximation-based global search algorithm is suggested to solve resource-constrained allocation in high level synthesis problems. Value approximation is preferred, because it can start by using expert heuristics, can estimate the global structure of the search problem, and can optimize heuristics. We are concerned by those allocation problems that have hidden global structure that value approximation may unravel. The value approximation applied here computes the cost of the actual solution and estimates the cost of the solution that could be achieved upon performing a global search on the hidden structure starting from the actual solution. We transcribed the allocation problem into a special form of weighted CNF formulae to suit our approach. We also extended the formalism to pipeline operations. Comparisons are made with expert heuristics. Scaling of computation time and performance are compared.
    BibTeX:
    @article{palotai02value,
      author = {{\Zs}. Palotai and T. Kand{\'a}r and Z. Mohr and T. Visegr{\'a}dy and G. Ziegler and P. Arat{\'o} and A. L{\H{o}}rincz},
      title = {Value prediction in {HLS} allocation problems using intellectual properties},
      journal = {Applied Artificial Intelligence},
      year = {2002},
      volume = {16},
      pages = {151-192},
    }					
    Szatmáry, B., Póczos, B., Eggert, J., Körner, E. & Lőrincz, A. Non-negative matrix factorization extended by sparse code shrinkage and by weight sparsification 2002 ECAI2002, Proceedings of the 15th European Conference on Artificial Intelligence   inproceedings ANN
    Abstract: Properties of a novel algorithm called non-negative matrix factorization (NMF), are studied. NMF can discover substructures and can provide estimations about the presence or the absence of those, being attractive for completion of missing information. We have studied the working and learning capabilities of NMF networks. Performance was improved by adding sparse code shrinkage (SCS) algorithm to remove structureless noise. We have found that NMF performance is considerably improved by SCS noise filtering. For improving noise resistance in the learning phase, weight sparsification was studied; a sparsifying prior was applied on the NMF weight matrix. Learning capability versus noise content was measured with and without sparsifying prior. In accordance with observation made by others on independent component analysis, we have also found that weight sparsification improved learning capabilities in the presence of Gaussian noise.
    BibTeX:
    @inproceedings{szatmary02non-negative,
      author = {B. Szatm{\'a}ry and B. P{\'o}czos and J. Eggert and E. K{\"o}rner and A. L{\H{o}}rincz},
      title = {Non-negative matrix factorization extended by sparse code shrinkage and by weight sparsification},
      booktitle = {ECAI2002, Proceedings of the 15th European Conference on Artificial Intelligence},
      year = {2002},
      pages = {503-507},
    }					
    Szirtes, G., Palotai, Zs. & Lőrincz, A. HebbNets: Dynamic network with Hebbian learning rule 2002   techreport
    Abstract: It has been demonstrated that one of the most striking features of the nervous system, the so called 'plasticity' (i.e high adaptability at different structural levels) is primarily based on Hebbian learning which is a collection of slightly different mechanisms that modify the synaptic connections between neurons. The changes depend on neural activity and assign a special dynamic behavior to the neural networks. From a structural point of view, it is an open question what network structures may emerge in such dynamic structures under 'sustained' conditions when input to the system is only noise. In this paper we present and study the 'HebbNets', networks with random noise input, in which structural changes are exclusively governed by neurobiologically inspired Hebbian learning rules. We show that Hebbian learning is able to develop a broad range of network structures, including scale-free small-world networks.
    BibTeX:
    @techreport{szirtes02hebbnets_TR,
      author = {G. Szirtes and {\Zs}. Palotai and A. L{\H{o}}rincz},
      title = {HebbNets: Dynamic network with {Hebbian} learning rule},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2002},
      address = {Budapest},
      url = {http://arxiv.org/abs/nlin/0212010},
    }					
    Szirtes, G. & Lőrincz, A. Low level priming as a consequence of perception 2002 Connectionist Models of Cognition and Perception   inproceedings cog, ANN, ICA
    BibTeX:
    @inproceedings{szirtes02low,
      author = {G. Szirtes and A. L{\H{o}}rincz},
      title = {Low level priming as a consequence of perception},
      booktitle = {Connectionist Models of Cognition and Perception},
      year = {2002},
      pages = {223-235},
      address = {Singapore},
      publisher = {World Scientific},
      note = {NCPW7},
    }					
    Szita, I., Takács, B. & Lőrincz, A. Event-learning with a non-Markovian controller 2002 ECAI2002, Proceedings of the 15th European Conference on Artificial Intelligence   inproceedings RL
    Abstract: Recently a novel reinforcement learning algorithm called event-learning or E-learning was introduced. The algorithm based on events, which are defined as ordered pairs of states. In this setting, the agent optimizes the selection of desired sub-goals by a traditional value-policy function iteration, and utilizes a separated algorithm called the controller to achieve these goals. The advantage of event-learning lies in its potential in non-stationary environments, where the near-optimality of the value iteration is guaranteed by the generalized epsilon-stationary MDP model. Using a particular non-Markovian controller, the SDS controller, an epsilon-MDP problem arises in E-learning. We illustrate the properties of E-learning augmented by the SDS controller by computer simulations.
    BibTeX:
    @inproceedings{szita02event,
      author = {I. Szita and B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Event-learning with a non-{Markovian} controller},
      booktitle = {ECAI2002, Proceedings of the 15th European Conference on Artificial Intelligence},
      year = {2002},
      pages = {365-369},
    }					
    Szita, I. Nem teljesen Markov döntési folyamatok (Epsilon-Markov decision processes) 2002 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{szita02nemteljesen,
      author = {I. Szita},
      title = {Nem teljesen {Markov} d{\"o}nt{\'e}si folyamatok ({E}psilon-{Markov} decision processes)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2002},
      address = {Budapest},
    }					
    Szita, I., Takács, B. & Lőrincz, A. Reinforcement Learning Integrated with a Non-Markovian Controller 2002 European Conference on Artificial Intelligence (ECAI)   inproceedings RL
    BibTeX:
    @inproceedings{szita02reinforcement,
      author = {I. Szita and B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Reinforcement Learning Integrated with a Non-{Markovian} Controller},
      booktitle = {European Conference on Artificial Intelligence (ECAI)},
      year = {2002},
      pages = {365--369},
    }					
    Szita, I., Takács, B. & Lőrincz, A. Searching for Plannable Domains can Speed up Reinforcement Learning 2002   techreport
    Abstract: Reinforcement learning (RL) involves sequential decision making in uncertain environments. The aim of the decision-making agent is to maximize the benefit of acting in its environment over an extended period of time. Finding an optimal policy in RL may be very slow. To speed up learning, one often used solution is the integration of planning, for example, Sutton's Dyna algorithm, or various other methods using macro-actions. Here we suggest to separate plannable, i.e., close to deterministic parts of the world, and focus planning efforts in this domain. A novel reinforcement learning method called plannable RL (pRL) is proposed here. pRL builds a simple model, which is used to search for macro actions. The simplicity of the model makes planning computationally inexpensive. It is shown that pRL finds an optimal policy, and that plannable macro actions found by pRL are near-optimal. In turn, it is unnecessary to try large numbers of macro actions, which enables fast learning. The utility of pRL is demonstrated by computer simulations.
    BibTeX:
    @techreport{szita02searching_TR,
      author = {I. Szita and B. Tak{\'a}cs and A. L{\H{o}}rincz},
      title = {Searching for Plannable Domains can Speed up Reinforcement Learning},
      institution = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2002},
      address = {Budapest},
      url = {http://arxiv.org/abs/cs/0212025},
    }					
    Fomin, T. From adaptive clusterization to self-organizing neurocontrol 2001 School: Eötvös Loránd University   phdthesis
    BibTeX:
    @phdthesis{fomin01adaptive,
      author = {T. Fomin},
      title = {From adaptive clusterization to self-organizing neurocontrol},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2001},
      address = {Budapest},
    }					
    Grad, L. & Mészáros, R. Paraméterezett modell illesztése a STAGE algoritmus segitségével (Optimization of parameterized models using algorithm STAGE) 2001 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{grad01parameterezett,
      author = {L. Grad and R. M{\'e}sz{\'a}ros},
      title = {Param{\'e}terezett modell illeszt{\'e}se a {STAGE} algoritmus seg{\'\i}ts{\'e}g{\'e}vel ({O}ptimization of parameterized models using algorithm {STAGE})},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2001},
      address = {Budapest},
    }					
    Kókai, I. Intelligens hálózati barangoló (Intelligent web crawler) 2001 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{kokai01intelligens,
      author = {I. K{\'o}kai},
      title = {Intelligens h{\'a}l{\'o}zati barangol{\'o} ({I}ntelligent web crawler)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2001},
      address = {Budapest},
    }					
    Lőrincz, A. Global ambient intelligence: The hostess concept 2001 NEWS of the European Research Consortium for Informatics and Mathematics (ERCIM NEWS), Special Issue on Ambient Intelligence   article AmI
    BibTeX:
    @article{lorincz01global,
      author = {A. L{\H{o}}rincz},
      title = {Global ambient intelligence: The hostess concept},
      journal = {NEWS of the European Research Consortium for Informatics and Mathematics (ERCIM NEWS), Special Issue on Ambient Intelligence},
      year = {2001},
      volume = {47},
      pages = {24-25},
    }					
    Lőrincz, A., Szirtes, G., Takács, B. & Buzsáki, Gy. Independent component analysis of temporal sequences forms place cells 2001 Neurocomputing   article neuro, ICA
    Abstract: It has been suggested that sensory information processing makes use of a factorial code. It has been shown that the major components of the hippocampal-entorhinal loop can be derived by conjecturing that the task of this loop is forming and encoding independent components (ICs), one type of factorial codes. However, continuously changing environment poses additional requirements on the coding that can be (partially) satisfied by extending the analysis to the temporal domain and performing IC analysis on concatenated inputs of time slices. We use computer simulations to decide whether IC analysis on temporal sequences can produce place fields in labyrinths or not.
    BibTeX:
    @article{lorincz01independent,
      author = {A. L{\H{o}}rincz and G. Szirtes and B. Tak{\'a}cs and {\Gy}. Buzs{\'a}ki},
      title = {Independent component analysis of temporal sequences forms place cells},
      journal = {Neurocomputing},
      year = {2001},
      volume = {38},
      pages = {769-774},
    }					
    Lőrincz, A., Hévízi, Gy. & Szepesvári, Cs. Ockham's razor modeling of the matrisome channels of the basal ganglia thalamocortical loop 2001 International Journal of Neural Systems   article neuro, BG
    Abstract: A functional model of the basal ganglia-thalamocortical (BTC) loops is described. In our modeling effort, we try to minimize the complexity of our starting hypotheses. For that reason, we call this type of modeling Ockham's razor modeling. We have the additional constraint that the starting assumptions should not contradict experimental findings about the brain. First assumption: The brain lacks direct representation of paths but represents directions (called speed fields in control theory). Then control should be concerned with speed-field tracking (SFT). Second assumption: Control signals are delivered upon differencing in competing parallel channels of the BTC loops. This is modeled by extending SFT with differencing that gives rise to the robust Static and Dynamic State (SDS) feedback-controlling scheme. Third assumption: Control signals are expressed in terms of a gelatinous medium surrounding the limbs. This is modeled by expressing parameters of motion in parameters of the external space. We show that corollaries of the model fit properties of the BTC loops. The SDS provides proper identification of motion related neuronal groups of the putamen. Local minima arise during the controlling process that works in external space. The model explains the presence of parallel channels as the means to avoiding such local minima. Stability conditions of the SDS predict that the initial phase of learning is mostly concerned with selection of sign for the inverse dynamics. The model provides a scalable controller. State description in external space instead of configurational space reduces the dimensionality problem. Falsifying experiment is suggested. Computer experiments demonstrate the feasibility of the approach. We argue that the resulting scheme has a straightforward connectionist representation exhibiting population coding and Hebbian learning properties.
    BibTeX:
    @article{lorincz01ockham,
      author = {A. L{\H{o}}rincz and {\Gy}. H{\'e}v{\'\i}zi and {\Cs}. Szepesv{\'a}ri},
      title = {Ockham's razor modeling of the matrisome channels of the basal ganglia thalamocortical loop},
      journal = {International Journal of Neural Systems},
      year = {2001},
      volume = {11},
      pages = {125-143},
    }					
    Lőrincz, A., Szatmáry, B., Szirtes, G. & Takács, B. Recognition of novelty made easy: Constraints of channel capacity on generative networks 2001 Connectionist Models of Learning, Development and Evolution   inproceedings cog, ANN
    BibTeX:
    @inproceedings{lorincz01recognition,
      author = {A. L{\H{o}}rincz and B. Szatm{\'a}ry and G. Szirtes and B. Tak{\'a}cs},
      title = {Recognition of novelty made easy: Constraints of channel capacity on generative networks},
      booktitle = {Connectionist Models of Learning, Development and Evolution},
      year = {2001},
      pages = {73-82},
      publisher = {Springer Verlag},
      note = {NCPW6},
    }					
    Lőrincz, A., Szatmáry, B. & Kabán, A. Sign-changing filters similar to cells in primary visual cortex emerge by independent component analysis of temporally convolved natural image sequences 2001 Neurocomputing   article neuro, ICA
    Abstract: It has been reported that independent component analysis (ICA) of natural image sequences yields spatio-temporal filters of non-separable spatio-temporal properties. On the contrary, sign changing filters with separable spatio-temporal properties have not been found via ICA. We show that extending the ICA to temporally convolved inputs develops such receptive fields (RFs). We argue that temporal convolution may arise from the response function of lagged and non-lagged cells of the LGN. The properties of the emerging RFs as a function of convolution time and the dimension of compression are studied.
    BibTeX:
    @article{lorincz01sign-changing,
      author = {A. L{\H{o}}rincz and B. Szatm{\'a}ry and A. Kab{\'a}n},
      title = {Sign-changing filters similar to cells in primary visual cortex emerge by independent component analysis of temporally convolved natural image sequences},
      journal = {Neurocomputing},
      year = {2001},
      volume = {38},
      pages = {1437-1442},
    }					
    Szatmáry, B. & Lőrincz, A. Independent component analysis of temporal sequences subject to constraints by LGN inputs yields all the three major cell types of the primary visual cortex 2001 Journal of Computational Neuroscience   article neuro, ICA
    Abstract: Information maximization has long been suggested as the underlying coding strategy of the primary visual cortex (V1). Grouping image sequences into blocks has been shown by others to improve agreement between experiments and theory. We have studied the effect of temporal convolution on the formation of spatiotemporal filters--that is, the analogues of receptive fields--since this temporal feature is characteristic to the response function of lagged and nonlagged cells of the lateral geniculate nucleus. Concatenated input sequences were used to learn the linear transformation that maximizes the information transfer. Learning was accomplished by means of principal component analysis and independent component analysis. Properties of the emerging spatiotemporal filters closely resemble the three major types of V1 cells: simple cells with separable receptive field, simple cells with nonseparable receptive field, and complex cells.
    BibTeX:
    @article{szatmary01independent,
      author = {B. Szatm{\'a}ry and A. L{\H{o}}rincz},
      title = {Independent component analysis of temporal sequences subject to constraints by {LGN} inputs yields all the three major cell types of the primary visual cortex},
      journal = {Journal of Computational Neuroscience},
      year = {2001},
      volume = {11},
      pages = {241-248},
    }					
    Vogels, R., Biederman, I., Bar, M. & Lőrincz, A. Inferior temporal neurons show greater sensitivity to nonaccidental than to metric shape differences 2001 Journal of Cognitive Neuroscience   article neuro
    Abstract: It has long been known that macaque inferior temporal (IT) neurons tend to fire more strongly to some shapes than to others, and that different IT neurons can show markedly different shape preferences. Beyond the discovery that these preferences can be elicited by features of moderate complexity, no general principle of (nonface) object recognition had emerged by which this enormous variation in selectivity could be understood. Psychophysical, as well as computational work, suggests that one such principle is the difference between viewpoint-invariant, nonaccidental (NAP) and view-dependent, metric shape properties (MPs). We measured the responses of single IT neurons to objects differing in either a NAP (namely, a change in a geon) or an MP of a single part, shown at two orientations in depth. The cells were more sensitive to changes in NAPs than in MPs, even though the image variation (as assessed by wavelet-like measures) produced by the former were smaller than the latter. The magnitude of the response modulation from the rotation itself was, on average, similar to that produced by the NAP differences, although the image changes from the rotation were much greater than that produced by NAP differences. Multidimensional scaling of the neural responses indicated a NAP/MP dimension, independent of an orientation dimension. The present results thus demonstrate that a significant portion of the neural code of IT cells represents differences in NAPs rather than MPs. This code may enable immediate recognition of novel objects at new views.
    BibTeX:
    @article{vogels01inferior,
      author = {R. Vogels and I. Biederman and M. Bar and A. L{\H{o}}rincz},
      title = {Inferior temporal neurons show greater sensitivity to nonaccidental than to metric shape differences},
      journal = {Journal of Cognitive Neuroscience},
      year = {2001},
      volume = {13},
      pages = {444--453},
    }					
    Ziegler, G., Palotai, Zs., Cinkler, T., Arató, P. & Lőrincz, A. Value prediction in engineering applications 2001 Lecture Notes in Artificial Intelligence   article HW
    Abstract: In engineering application heuristics are widely used for discrete optimization tasks. We report two cases (in DenseWavelength Division Multiplexing and High Level Synthesis), where a recent 'intelligent' heuristic (STAGE) performs excellently by learning a value-function of the states. We have found that if a global structure of local minima is found by the function approximator then search time may not have to scale with the dimension of the problem in the exponent, but it may become a polynomial function of the dimension.
    BibTeX:
    @article{ziegler01value,
      author = {G. Ziegler and {\Zs}. Palotai and T. Cinkler and P. Arat{\'o} and A. L{\H{o}}rincz},
      title = {Value prediction in engineering applications},
      journal = {Lecture Notes in Artificial Intelligence},
      year = {2001},
      volume = {2070},
      pages = {25-34},
    }					
    Chrobak, J. J., Lőrincz, A. & Buzsáki, Gy. Physiological patterns in the hippocampo-entorhinal cortex system 2000 Hippocampus   article neuro, HC
    Abstract: The anatomical connectivity and intrinsic properties of entorhinal cortical neurons give rise to ordered patterns of ensemble activity. How entorhinal ensembles form, interact, and accomplish emergent processes such as memory formation is not well-understood. We lack sufficient understanding of how neuronal ensembles in general can function transiently and distinctively from other neuronal ensembles. Ensemble interactions are bound, foremost, by anatomical connectivity and temporal constraints on neuronal discharge. We present an overview of the structure of neuronal interactions within the entorhinal cortex and the rest of the hippocampal formation. We wish to highlight two principle features of entorhinal-hippocampal interactions. First, large numbers of entorhinal neurons are organized into at least two distinct high-frequency population patterns: gamma (40--100 Hz) frequency volleys and ripple (140--200 Hz) frequency volleys. These patterns occur coincident with other well-defined electrophysiological patterns. Gamma frequency volleys are modulated by the theta cycle. Ripple frequency volleys occur on each sharp wave event. Second, these patterns occur dominantly in specific layers of the entorhinal cortex. Theta/gamma frequency volleys are the principle pattern observed in layers I--III, in the neurons that receive cortical inputs and project to the hippocampus. Ripple frequency volleys are the principle population pattern observed in layers V--VI, in the neurons that receive hippocampal output and project primarily to the neocortex. Further, we will highlight how these ensemble patterns organize interactions within distributed forebrain structures and support memory formation.
    BibTeX:
    @article{chrobak00physiological,
      author = {J. J. Chrobak and A. L{\H{o}}rincz and {\Gy}. Buzs{\'a}ki},
      title = {Physiological patterns in the hippocampo-entorhinal cortex system},
      journal = {Hippocampus},
      year = {2000},
      volume = {10},
      pages = {457-465},
    }					
    Hévízi, Gy. Kvantumrendszerek állapot-optimalizációja eredményesség-visszacsatolás segitségével (Optimization of quantum systems) 2000 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{hevizi00kvantumrendszerek,
      author = {{\Gy}. H{\'e}v{\'\i}zi},
      title = {Kvantumrendszerek {\'a}llapot-optimaliz{\'a}ci{\'o}ja eredm{\'e}nyess{\'e}g-visszacsatol{\'a}s seg{\'\i}ts{\'e}g{\'e}vel ({O}ptimization of quantum systems)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2000},
      address = {Budapest},
    }					
    Kalmár, Zs., Szepesvári, Cs. & Lőrincz, A. Modular reinforcement learning: A case study in a robot domain 2000 Acta Cybernetica   article RL
    BibTeX:
    @article{kalmar00modular,
      author = {{\Zs}. Kalm{\'a}r and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Modular reinforcement learning: A case study in a robot domain},
      journal = {Acta Cybernetica},
      year = {2000},
      volume = {14},
      pages = {507-522},
    }					
    Lőrincz, A. & Buzsáki, Gy. Two-phase computational model of the entorhinal-hippocampal region 2000 The parahippocampal region: Implications for neurological and psychiatric diseases   inproceedings neuro, HC, ICA
    Abstract: The computational model described here is driven by the hypothesis that a major function of the entorhinal cortex (EC)-hippocampal system is to alter synaptic connections in the neocortex. It is based on the following postulates: (1) The EC compares the difference between neocortical representations (primary input) and feedback information conveyed by the hippocampus (the 'reconstructed input'). The difference between the primary input and the reconstructed input (termed 'error') initiates plastic changes in the hippocampal networks (error compensation). (2) Comparison of the primary input and reconstructed input requires that these representations are available simultaneously in the EC network. We suggest that compensation of time delays is achieved by predictive structures, such as the CA3 recurrent network and EC-CA1 connections. (3) Alteration of intrahippocampal connections gives rise to a new hippocampal output. The hippocampus generates separated (independent) outputs, which, in turn, train long-term memory traces in the EC (independent components, IC). The ICs of the long-term memory trace are generated in a two-step manner, the operations of which we attribute to the activities of the CA3 (whitening) and CA1 (separation) fields. (4) The different hippocampal fields can perform both nonlinear and linear operations, albeit at different times (theta and sharp phases). We suggest that long-term memory is represented in a distributed and hierarchical reconstruction network, which is under the supervision of the hippocampal output. Several of these model predictions can be tested experimentally.
    BibTeX:
    @inproceedings{lorincz00two-phase,
      author = {A. L{\H{o}}rincz and {\Gy}. Buzs{\'a}ki},
      title = {Two-phase computational model of the entorhinal-hippocampal region},
      booktitle = {The parahippocampal region: Implications for neurological and psychiatric diseases},
      year = {2000},
      editor = {H. E. Sharfman and M. P. Witter and R. Schwarcz},
      note = {Annals of the New York Academy of Sciences 911: 83-111},
    }					
    Szatmáry, B. Természetes képsorokon végzett független analizis alkalmazása elsődleges látókérgi sejtek modellezésében (Independent component analysis of images sequences: Modeling the primary visual cortex) 2000 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{szatmary00termeszetes,
      author = {B. Szatm{\'a}ry},
      title = {Term{\'e}szetes k{\'e}psorokon v{\'e}gzett f{\"u}ggetlen anal{\'\i}zis alkalmaz{\'a}sa els{\H{o}}dleges l{\'a}t{\'o}k{\'e}rgi sejtek modellez{\'e}s{\'e}ben ({I}ndependent component analysis of images sequences: Modeling the primary visual cortex)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2000},
      address = {Budapest},
    }					
    Takács, B. Neurális rendszerek funkcionális modellezése (Model of the hippocampus) 2000 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{takacs00neuralis,
      author = {B. Tak{\'a}cs},
      title = {Neur{\'a}lis rendszerek funkcion{\'a}lis modellez{\'e}se ({M}odel of the hippocampus)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {2000},
      address = {Budapest},
    }					
    Aszalós, P., Kéri, Sz., Kovács, Gy., Benedek, Gy., Janka, Z. & Lőrincz, A. Generative network explains category formation in Alzheimer patients 1999 Int. Joint Conf. on Neural Networks   inproceedings cog, ANN
    Abstract: This paper presents a generative data reconstruction neural network model equipped with plastic lateral connections. The model is capable of capturing basic phenomena related to category formation. It explains category formation as an effect of cumulative memory traces at the level of lateral connectivity. The formed memory traces change network activity that is the basis of categorization according to the model. This change however depends on the structure of the lateral connectivity and on the stimuli used in demonstrations. We argue that the model resolves the seemingly contradictory demonstrational results carried out with Alzheimer disease (AD) patients on category formation. We consider different stimulus sets and degraded lateral connectivity and show that the categorization probability can change from monotone to non-monotone functions depending on the sets.
    BibTeX:
    @inproceedings{aszalos99generative,
      author = {P. Aszal{\'o}s and {\Sz}. K{\'e}ri and {\Gy}. Kov{\'a}cs and {\Gy}. Benedek and Z. Janka and A. L{\H{o}}rincz},
      title = {Generative network explains category formation in {Alzheimer} patients},
      booktitle = {Int. Joint Conf. on Neural Networks},
      year = {1999},
      address = {Washington},
      note = {IJCNN2137.PDF, IEEE Catalog Number: 99CH36339C},
    }					
    Fodor, I. A megerősitéses tanulás elvén működő tanulórendszer elemzése (Analysis of a learning system subject to reinforcement learning) 1999 School: József Attila University   mastersthesis
    BibTeX:
    @mastersthesis{fodor99megerositeses,
      author = {I. Fodor},
      title = {A meger{\H{o}}s{\'\i}t{\'e}ses tanul{\'a}s elv{\'e}n m{\H{u}}k{\"o}d{\H{o}} tanul{\'o}rendszer elemz{\'e}se ({A}nalysis of a learning system subject to reinforcement learning)},
      school = {J{\'o}zsef Attila University},
      year = {1999},
      address = {Szeged},
    }					
    Kalmár, Zs., Marczell, Zs., Szepesvári, Cs. & Lőrincz, A. Parallel and robust skeletonization built from self-organizing elements 1999 Neural Networks   article ANN
    Abstract: A massively parallel neural architecture is suggested for the approximate computation of the skeleton of a planar shape. Numerical examples demonstrate the robustness of the method. The architecture is constructed from self-organizing elements that allow the extension of the concept of skeletonization to areas remote to image processing.
    BibTeX:
    @article{kalmar99parallel,
      author = {{\Zs}. Kalm{\'a}r and {\Zs}. Marczell and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Parallel and robust skeletonization built from self-organizing elements},
      journal = {Neural Networks},
      year = {1999},
      volume = {12},
      pages = {163-173},
    }					
    Kiss, B. Nemlineáris rendszerek optimalizálása és robusztus szabályozása: Alkalmazás bioreaktor közelitő egyenleteire (Optimization and robust control of non-linear dynamical systems Application for approximate equations of a bioreactor) 1999 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{kiss99nemlinearis,
      author = {B. Kiss},
      title = {Nemline{\'a}ris rendszerek optimaliz{\'a}l{\'a}sa {\'e}s robusztus szab{\'a}lyoz{\'a}sa: Alkalmaz{\'a}s bioreaktor k{\"o}zel{\'\i}t{\H{o}} egyenleteire ({O}ptimization and robust control of non-linear dynamical systems Application for approximate equations of a bioreactor)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {1999},
      address = {Budapest},
    }					
    Körmendy-Rácz, J., Szabó, Sz., Lőrincz, J., Antal, Gy., Kovács, Gy. & Lőrincz, A. Winner-take-all network utilizing pseudoinverse reconstruction subnets demonstrates robustness on the handprinted character recognition problem 1999 Neural Computing and Applications   article ANN
    Abstract: Wittmeyer's pseudoinverse iterative algorithm is formulated as a dynamic connectionist Data Compression and Reconstruction (DCR) network, and subnets of this type are supplemented by the winnertake-all paradigm. The winner is selected upon the goodness-of-fit of the input reconstruction. The network can be characterised as a competitive-cooperative-competitive architecture by virtue of the contrast enhancing properties of the pseudoinverse subnets. The network is capable of fast learning. The adopted learning method gives rise to increased sampling in the vicinity of dubious boundary regions that resembles the phenomenon of categorical perception. The generalising abilities of the scheme allow one to utilise single bit connection strengths. The network is robust against input noise and contrast levels, shows little sensitivity to imprecise connection strengths, and is promising for mixed VLSI implementation with on-chip learning properties. The features of the DCR network are demonstrated on the NIST database of handprinted characters.
    BibTeX:
    @article{kormendy99winner-take-all,
      author = {J. {K{\"o}rmendy-R{\'a}cz} and {\Sz}. Szab{\'o} and J. L{\H{o}}rincz and {\Gy}. Antal and {\Gy}. Kov{\'a}cs and A. L{\H{o}}rincz},
      title = {Winner-take-all network utilizing pseudoinverse reconstruction subnets demonstrates robustness on the handprinted character recognition problem},
      journal = {Neural Computing and Applications},
      year = {1999},
      volume = {8},
      pages = {163-176},
    }					
    Lőrincz, A. & Buzsáki, Gy. Computational model of the entorhinal-hippocampal region derived from a single principle 1999 Int. Joint Conf. on Neural Networks   inproceedings neuro, HC, ICA
    Abstract: We show that several properties of the highly elaborate structure of the EC-HC loop can be explained using the single principle that to recall past and to foresee future events a predictive structure is necessary. Prediction based on information merging from a high dimensional sensory system becomes less demanding if the processed sensory information can be separated into components that evolve independently. Networks that develop independent components (ICs) in an efficient manner can be built from two stages. We identify these stages with the CA3 and CA1 layers of the hippocampus (HC). The forming of ICs requires non-linear operation, whereas IC outputs arise under linear operation and thus two-phase operation follows. Concurrent occurrences of past and present events are required by Hebbian learning and can be achieved by delaying structures, e.g., by loops. The loop structure requires a third layer that we identify with the entorhinal cortex (EC). The output is not modified if the loop forms a dynamic reconstructing (generative) network (DRN), i.e., if the EC encodes a representation of the ICs. Proper encoding into the EC is possible during linear operation in a supervised manner. The DRN can be seen as an error compensating control architecture. The HC part of the DRN is inputted by the error, the mismatch between the primary input to the EC-HC loop and the reconstructed input conveyed by the hippocampus. Errors between primary input and reconstructed input can arise when the information is 'novel'. Delays can be compensated by tuned predictive structures. The two-phase operation requires two predictive structures. We assume that those correspond to the EC to CA1 connections that operate during theta phase and the recurrent collateral system of the CA3 field that operates during sharp wave phase. Learning modifies the memory system that may temporarily spoil the predictive network. Thus the novel information processed by the DRN may be temporally convolved. Convolution should be counteracted before IC analysis. We assume that blind source deconvolution is executed by the dentate gyrus and show that the dentate gyrus can satisfy the requirements.
    BibTeX:
    @inproceedings{lorincz99computational,
      author = {A. L{\H{o}}rincz and {\Gy}. Buzs{\'a}ki},
      title = {Computational model of the entorhinal-hippocampal region derived from a single principle},
      booktitle = {Int. Joint Conf. on Neural Networks},
      year = {1999},
      address = {Washington},
      note = {IJCNN2136.PDF, IEEE Catalog Number: 99CH36339C},
    }					
    Lőrincz, A., Csató, L., Gábor, Z. & Buzsáki, Gy. Two-stage computational model of the entorhinal-hippocampal loop 1999 Annual Meeting of the Neural Society   inproceedings neuro, HC, ICA
    BibTeX:
    @inproceedings{lorincz99two-stage,
      author = {A. L{\H{o}}rincz and L. Csat{\'o} and Z. G{\'a}bor and {\Gy}. Buzs{\'a}ki},
      title = {Two-stage computational model of the entorhinal-hippocampal loop},
      booktitle = {Annual Meeting of the Neural Society},
      year = {1999},
      address = {Los Angeles},
    }					
    Nagy, T. Dimenzióredukciós mesterséges neuronháló es megerősítéses tanulás elvén működő tanulórendszer elemzése 1999 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{nagy99dimenzioredukcios,
      author = {T. Nagy},
      title = {Dimenzi{\'o}redukci{\'o}s mesters{\'e}ges neuronh{\'a}l{\'o} es meger{\H{o}}s{\'i}t{\'e}ses tanul{\'a}s elv{\'e}n m{\H{u}}k{\"o}d{\H{o}} tanul{\'o}rendszer elemz{\'e}se},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {1999},
      address = {Budapest},
    }					
    Nagy, T. Megerősitéses tanulás és játszmák (Reinforcement learning and games) 1999 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{nagy99megerositeses,
      author = {T. Nagy},
      title = {Meger{\H{o}}s{\'\i}t{\'e}ses tanul{\'a}s {\'e}s j{\'a}tszm{\'a}k ({R}einforcement learning and games)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {1999},
      address = {Budapest},
    }					
    Oláh, M., Török, S., Poppe, A., Masa, P. & Lőrincz, A. Design and evaluation of a grassfire skeletonization chip 1999 Proceedings of Conf. MIXDES99   inproceedings HW
    BibTeX:
    @inproceedings{olah99design,
      author = {M. Ol{\'a}h and S. T{\"o}r{\"o}k and A. Poppe and P. Masa and A. L{\H{o}}rincz},
      title = {Design and evaluation of a grassfire skeletonization chip},
      booktitle = {Proceedings of Conf. MIXDES99},
      year = {1999},
      address = {Poland},
      month = {July},
    }					
    Szabó, Sz. Waveletek alkalmazása a mozgásanalizisben (Wavelet image processing) 1999 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{szabo99waveletek,
      author = {{\Sz}. Szab{\'o}},
      title = {Waveletek alkalmaz{\'a}sa a mozg{\'a}sanal{\'\i}zisben ({W}avelet image processing)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {1999},
      address = {Budapest},
    }					
    Carpenter, S. D., Weber, P. M., Peter, J., Szabó, G., Szakács, T. & Lőrincz, A. Self-learning optical system based on a genetic-algorithm driven spatial light modulator 1998 Second GR-I International Conference on New Laser Technologies and Applications   inproceedings
    Abstract: We demonstrate the applicability of a genetic algorithm (GA) to control the focus of an adaptive optical system using a liquid crystal spatial light modulator. The optical setup and the algorithm applied are set to fitness type reinforcement for learning. The particular GA developed optimizes the phase shifts in 32 independent pixels, and is biased towards approximating continuous functions that suit the focusing problem. The learning process is demonstrated to work reliably even in the presence of experimental noise.
    BibTeX:
    @inproceedings{carpenter98self,
      author = {S. D. Carpenter and P. M. Weber and J. Peter and G. Szab{\'o} and T. Szak{\'a}cs and A. L{\H{o}}rincz},
      title = {Self-learning optical system based on a genetic-algorithm driven spatial light modulator},
      booktitle = {Second {GR-I} International Conference on New Laser Technologies and Applications},
      year = {1998},
      editor = {Alexis Carabelas and Paolo Di Lazzaro and Amalia Torre and Giuseppe Baldacchini},
      volume = {3423},
      pages = {130-134},
      month = {July},
    }					
    Kalmár, Zs., Szepesvári, Cs. & Lőrincz, A. Modular reinforcement learning: An application to a real robot task 1998 European Workshop on Learning Robot (EWLR)   inproceedings RL
    Abstract: The behaviour of reinforcement learning (RL) algorithms is best understood in completely observable, finite state- and action-space, discrete-time controlled Markov-chains. Robot-learning domains, on the other hand, are inherently infinite both in time and space, and moreover they are only partially observable. In this article we suggest a systematic design method whose motivation comes from the desire to transform the task-to-be-solved into a finite-state, discrete-time, 'approximately' Markovian task, which is completely observable too. The key idea is to break up the problem into subtasks and design controllers for each of the subtasks. Then operating conditions are attached to the controllers (together the controllers and their operating conditions which are called modules) and possible additional features are designed to facilitate observability. A new discrete time-counter is introduced at the 'module-level' that clicks only when a change in the value of one of the features is observed. The approach was tried out on a real-life robot. Several RL algorithms were compared and it was found that a model-based approach worked best. The learnt switching strategy performed equally well as a handcrafted version. Moreover, the learnt strategy seemed to exploit certain properties of the environment which could not have been seen in advance, which predicted the promising possibility that a learnt controller might overperform a handcrafted switching strategy in the future.
    BibTeX:
    @inproceedings{kalmar98modular,
      author = {{\Zs}. Kalm{\'a}r and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Modular reinforcement learning: An application to a real robot task},
      booktitle = {European Workshop on Learning Robot (EWLR)},
      year = {1998},
      volume = {1545},
      series = {Lecture Notes in Artificial Intelligence},
      pages = {29-45},
    }					
    Kalmár, Zs., Szepesvári, Cs. & Lőrincz, A. Module-based reinforcement learning: Experiments with a real robot 1998 Machine Learning   article RL
    Abstract: The behavior of reinforcement learning (RL) algorithms is best understood in completely observable, discrete-time controlled Markov chains with finite state and action spaces. In contrast, robot-learning domains are inherently continuous both in time and space, and moreover are partially observable. Here we suggest a systematic approach to solve such problems in which the available qualitative and quantitative knowledge is used to reduce the complexity of learning task. The steps of the design process are to: i) decompose the task into subtasks using the qualitative knowledge at hand; ii) design local controllers to solve the subtasks using the available quantitative knowledge and iii) learn a coordination of these controllers by means of reinforcement learning. It is argued that the approach enables fast, semi-automatic, but still high quality robot-control as no fine-tuning of the local controllers is needed. The approach was verified on a non-trivial real-life robot task. Several RL algorithms were compared by ANOVA and it was found that the model-based approach worked significantly better than the model-free approach. The learnt switching strategy performed comparably to a handcrafted version. Moreover, the learnt strategy seemed to exploit certain properties of the environment which were not foreseen in advance, thus supporting the viewthat adaptive algorithms are advantageous to non-adaptive ones in complex environments.
    BibTeX:
    @article{kalmar98module,
      author = {{\Zs}. Kalm{\'a}r and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Module-based reinforcement learning: Experiments with a real robot},
      journal = {Machine Learning},
      year = {1998},
      volume = {31},
      pages = {55-85},
      note = {Autonomous Robots 5: 273-295, 1998},
    }					
    Lőrincz, A. Basal ganglia perform differencing between 'desired' and 'experienced' parameters 1998 Computational Neural Science: Trends in Research   article neuro, BG
    BibTeX:
    @article{lorincz98basal,
      author = {A. L{\H{o}}rincz},
      title = {Basal ganglia perform differencing between 'desired' and 'experienced' parameters},
      journal = {Computational Neural Science: Trends in Research},
      year = {1998},
      pages = {77-82},
      note = {Plenum Press},
    }					
    Lőrincz, A. Forming independent components via temporal locking of reconstruction architectures: A functional model of the hippocampus 1998 Biological Cybernetics   article neuro, HC, ICA
    Abstract: The assumption is made that the formulation of relations as independent components (IC) is a main feature of computations accomplished by the brain. Further, it is assumed that memory traces made of non-orthonormal ICs make use of feedback architectures to form internal representations. Feedback then leads to delays, and delays in cortical processing form an obstacle to this relational processing. The problem of delay compensation is formulated as a speed-field tracking task and is solved by a novel control architecture. It is shown that in addition to delay compensation the control architecture can also shape long-term memories to hold independent components if a two-phase operation mode is assumed. Features such as a trisynaptic loop and a recurrent collateral structure at the second stage of that loop emerge in a natural fashion. Based on these properties a functional model of the hippocampal loop is constructed.
    BibTeX:
    @article{lorincz98forming,
      author = {A. L{\H{o}}rincz},
      title = {Forming independent components via temporal locking of reconstruction architectures: A functional model of the hippocampus},
      journal = {Biological Cybernetics},
      year = {1998},
      volume = {79},
      pages = {263-275},
      doi = {http://dx.doi.org/10.1007/s004220050476},
    }					
    Szepesvári, Cs. & Lőrincz, A. An integrated architecture for motion control and path planning 1998 Journal of Robotic Systems   article ANN
    Abstract: We consider the problem of learning how to control a plant with nonlinear control characteristics and solving the path-planning problem at the same time. The solution is based on a path-planning model that designates a speed field to be tracked, the speed field being the gradient of the equilibrium solution of a diffusionlike process which is simulated on an artificial neural network by spreading activation. The relaxed diffusion field serves as the input to the interneurons which etect the strength of activity flow in between neighboring discretizing neurons. These neurons then emit the control signals to control neurons which are linear elements. The interneuron to control-neuron connections are trained by a variant of Hebb's rule during control. The proposed method, whose most attractive feature is that it integrates reactive path-planning and continuous motion control in a natural fashion, can be used for learning redundant control problems.
    BibTeX:
    @article{szepesvari98integrated,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {An integrated architecture for motion control and path planning},
      journal = {Journal of Robotic Systems},
      year = {1998},
      volume = {15},
      pages = {1-15},
    }					
    Fomin, T., Körmendy-Rácz, J. & Lőrincz, A. Towards a unified model of cortical computation I: Data compression and data reconstruction architecture using dynamic feedback 1997 Neural Network World   article
    BibTeX:
    @article{fomin97towards,
      author = {T. Fomin and J. {K{\"o}rmendy-R{\'a}cz} and A. L{\H{o}}rincz},
      title = {Towards a unified model of cortical computation {I}: Data compression and data reconstruction architecture using dynamic feedback},
      journal = {Neural Network World},
      year = {1997},
      volume = {7},
      pages = {121-136},
    }					
    Lőrincz, A. Common control principles of basal ganglia - thalamocortical loops and the hippocampus 1997 Neural Network World   article
    BibTeX:
    @article{lorincz97common,
      author = {A. L{\H{o}}rincz},
      title = {Common control principles of basal ganglia - thalamocortical loops and the hippocampus},
      journal = {Neural Network World},
      year = {1997},
      volume = {6},
      pages = {649-677},
    }					
    Lőrincz, A. Hippocampal formation trains independent components via forcing input reconstruction 1997 Proceedings of ICANN'97   inproceedings
    BibTeX:
    @inproceedings{lorincz97hippocampal,
      author = {A. L{\H{o}}rincz},
      title = {Hippocampal formation trains independent components via forcing input reconstruction},
      booktitle = {Proceedings of ICANN'97},
      year = {1997},
      pages = {163-168},
      address = {Lausanne},
    }					
    Lőrincz, A. Neurocontrol III: Differencing models of the basal ganglia - thalamocortical loops 1997 Neural Network World   article
    Abstract: Two models of basal ganglia-thalamocortical loops are proposed, both of which feature population coding and utilize local approximations. The first model is a temporal differencing scheme similar to the temporal differencing striosome models [1,2]. In this model the basal ganglia perform temporal differencing by means of their two arms, viz. the direct and the indirect pathways. The second model involves control architecture based on the so called position-and-direction-to-action (PDA) map [3,4]. The architecture utilizes this PDA map for both static and dynamic state (SDS) feedback to achieve precise control under perturbed conditions [5]. Here it is argued that the differencing part of the SDS scheme may be viewed as a model of the basal ganglia, while the full SDS scheme may be considered as a model of basal ganglia -- thalamocortical loops. The SDS scheme is different from the temporal differencing model as it may also generate correcting commands if control is taken over and carried out by independent motor programme executing units. Relationships to neurobiological and psychophysical findings are discussed.
    BibTeX:
    @article{lorincz97neurocontrol,
      author = {A. L{\H{o}}rincz},
      title = {Neurocontrol {III}: Differencing models of the basal ganglia - thalamocortical loops},
      journal = {Neural Network World},
      year = {1997},
      volume = {7},
      pages = {43-72},
    }					
    Lőrincz, A. Static and dynamic state feedback control model of basal ganglia - thalamocortical loops 1997 International Journal of Neural Systems   article BG, neuro
    Abstract: It is argued that a novel control architecture, the Static and Dynamic State (SDS) feedback scheme, which utilizes speed-field tracking, exhibits global stability, and allows on-line tuning by any adaptation mechanism without cancelling stability if certain structural conditions are met, can be viewed as a model of basal ganglia-thalamocortical loops since (1) the SDS scheme predicts the neuronal groups that fit neuronal classification in the supplementary motor area, the motor cortex and the putamen, (2) the structural stability conditions require parallel channels, a feature that these loops provide, and (3) the SDS scheme predicts two major disorders that can be identified as Parkinson's and Huntington's diseases. Simulations suggests that the basal ganglia work outside the realm of the stability condition allowed by the robustness of the scheme and required for increased computation speeds.
    BibTeX:
    @article{lorincz97static,
      author = {A. L{\H{o}}rincz},
      title = {Static and dynamic state feedback control model of basal ganglia - thalamocortical loops},
      journal = {International Journal of Neural Systems},
      year = {1997},
      volume = {8},
      pages = {339-357},
    }					
    Lőrincz, A. Towards a unified model of cortical computation II: From control architecture to a model of consciousness 1997 Neural Network World   article
    Abstract: The recently introduced Static and Dynamic State (SDS) Feedback control scheme together with its modified form, the Data Compression and Reconstruction (DCR) architecture that performs pseudoinverse computation, suggests a unified model of cortical processing including consciousness. The constraints of the model are outlined were and the features of the cortical architecture that are suggested and sometimes dictated by these constraints are listed. Constraints are imposed on cortical layers, e.g., (1) the model prescribes a connectivity substructure that is shown to fit the main properties of the 'basic neural circuit' of the cerebral cortex (Shepherd and Koch [1], Douglas and Martin [2] In: The synaptic organization of the brain, Oxford University Press, 1990), and (2) the stability requirements of the pseudoinverse method offer an explanation for the columnar organization of the cortex. Constraints are also imposed on the hierarchy of cortical areas, e.g., the proposed control architecture requires computations of the control variables belonging to both the 'desired' and the 'experienced' moves as well as a 'sign-proper' separation of feedback channels that fit known properties of the basal ganglia -- thalamocortical loops [3]. An outline is given as to how the DCR scheme can be extended towards a model for consciousness that can deal with the 'homunculus fallacy' by resolving the fallacy and saving the homunculus as an inherited and learnt partially ordered list of preferences.
    BibTeX:
    @article{lorincz97towards,
      author = {A. L{\H{o}}rincz},
      title = {Towards a unified model of cortical computation {II}: From control architecture to a model of consciousness},
      journal = {Neural Network World},
      year = {1997},
      volume = {7},
      pages = {137-152},
    }					
    Oláh, M., Masa, P. & Lőrincz, A. A mixed signal VLSI circuit for skeletonization by grassfire transformation 1997 Proceedings of ICANN'97   inproceedings
    BibTeX:
    @inproceedings{olah97mixed,
      author = {M. Ol{\'a}h and P. Masa and A. L{\H{o}}rincz},
      title = {A mixed signal {VLSI} circuit for skeletonization by grassfire transformation},
      booktitle = {Proceedings of ICANN'97},
      year = {1997},
      pages = {1205-1210},
      address = {Lausanne},
    }					
    Szepesvári, Cs. & Lőrincz, A. Approximate inverse-dynamics based robust control using static and dynamic feedback 1997 Applications of Neural Adaptive Control Theory II   article ANN
    Abstract: It is rigorously shown that inverse-dynamics models can be used to stabilize plants of any order provided that the inverse-dynamic model is used in a mixed mode fashion, in that of a 'Static and Dynamic' State-feedback (SDS) mode. When the resulting controller is used for tracking increasing the gain of the dynamic feedback decreases the tracking error. Yet another attractive feature of the SDS scheme is that the inverse-dynamics model can be tuned on-line by any adaptation mechanism without cancelling stability if the conditions of the non-adaptive stability theorem hold at any time instant. Computer simulations of the control of a chaotic bioreactor and a 'realistic' robotic manipulator demonstrate the robustness of the approach. It is shown that SDS control will yield zero asymptotic error when controlling the bioreactor using an inverse-dynamics model which when used in a traditional mode would yield intolerably large errors. In the case of the robotic arm simulations the effects of perturbation and sampling frequency are investigated and the SDS control is compared with the non-adaptive computed torque method. A fully self-organizing associative neural network architecture that can be used to approximate the inverse-dynamics in the form of a Position-and-Direction-to-Action (PDA) map is also described. Similarities between the basal ganglia - thalamocortical loops and the SDS scheme are discussed and it is argued that the SDS scheme could be viewed as a model of higher order motor functions of these areas.
    BibTeX:
    @article{szepesvari97approximate,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Approximate inverse-dynamics based robust control using static and dynamic feedback},
      journal = {Applications of Neural Adaptive Control Theory II},
      year = {1997},
      volume = {2},
      pages = {151-179},
      note = {World Scientific, Singapore},
    }					
    Szepesvári, Cs., Cimmer, Sz. & Lőrincz, A. Neurocontroller Using Dynamic State Feedback for Compensatory Control 1997 Neural Networks   article ANN
    Abstract: A common technique in neurocontrol is that of controlling a plant by static state feedback using the plant's inverse dynamics, which is approximated through a learning process. It is well known that in this control mode even small approximation errors or, which is the same, small perturbations of the plant may lead to instability. Here, a novel approach is proposed to overcome the problem of instability by using the inverse dynamics both for the static and for the error-compensating dynamic state feedback control. This scheme is termed SDS feedback control. It is shown that as long as the error of the inverse dynamics model is 'signproper' the SDS feedback control is stable, i.e., the error of tracking may be kept small. The proof is based on a modification of Liapunov's second method. The problem of on-line learning of the inverse dynamics when using the controller simultaneously for both forward control and for dynamic feedback is dealt with, as are questions related to noise sensitivity and robust control of robotic manipulators. Simulations of a simplified sensorimotor loop serve to illustrate the approach.
    BibTeX:
    @article{szepesvari97dynamic,
      author = {{\Cs}. Szepesv{\'a}ri and {\Sz}. Cimmer and A. L{\H{o}}rincz},
      title = {Neurocontroller Using Dynamic State Feedback for Compensatory Control},
      journal = {Neural Networks},
      year = {1997},
      volume = {10},
      pages = {1691-1708},
    }					
    Szepesvári, Cs. & Lőrincz, A. Robust control using inverse dynamics neurocontrollers 1997 Nonlinear Analysis Theo., Meth. and Appl.   article ANN
    Abstract: Neurocontrollers typically realise static state feedback control where the neural network is used to approximate the inverse dynamics of the controlled plant [1]. In practice it is often unknown a priori how precise such an approximation can be. On the other hand, it is well known that in this control mode even small approximation errors can lead to instabilities [2]. The same happens if one is given a precise model of the inverse dynamics, but the plant's dynamics changes. The simplest example of this kind is when a robot arm grasps an object that is heavy compared to the arm. This problem can be solved by increasing the stiffness of the robot, i.e., if one assumes a 'strong' controller. Industrial controllers often meet this assumption, but recent interest has grown towards 'light' controllers, such as robot arms with air muscles that can be considerably faster [3]. There are well-known ways of neutralising the effects of unmodeled dynamics, such as the sigma-modification, signal normalisation, (relative) dead zone, and projection methods, being widely used and discussed in the control literature (see for example, [2]). Here a novel architecture that does direct identification of the inverse dynamics and a new method that utilizes this inverse dynamics controller in two copies are described. The result is robust controller of high precision put on a firm mathematical bases. The capabilities of the controller will be demostrated on a chaotic bioreactor. The attractive learning properties will be discussed.
    BibTeX:
    @article{szepesvari97robust,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Robust control using inverse dynamics neurocontrollers},
      journal = {Nonlinear Analysis Theo., Meth. and Appl.},
      year = {1997},
      volume = {30},
      pages = {1669-1676},
    }					
    Tavitian, S., Fomin, T. & Lőrincz, A. Abstracting spatial prototypes through short-term suppression of Hebbian weights in a continuously changig environment 1997 Neural Network World   article
    BibTeX:
    @article{tavitian97abstracting,
      author = {S. Tavitian and T. Fomin and A. L{\H{o}}rincz},
      title = {Abstracting spatial prototypes through short-term suppression of {Hebbian} weights in a continuously changig environment},
      journal = {Neural Network World},
      year = {1997},
      volume = {6},
      pages = {707-727},
    }					
    Tóth, G. J., Lőrincz, A. & Rabitz, H. The effect of quantum dispersion on laboratory feedback optimal control 1997 Journal of Modern Optics   article
    BibTeX:
    @article{toth97effect,
      author = {G. J. T{\'o}th and A. L{\H{o}}rincz and H. Rabitz},
      title = {The effect of quantum dispersion on laboratory feedback optimal control},
      journal = {Journal of Modern Optics},
      year = {1997},
      volume = {44},
      pages = {2049-2052},
    }					
    Fomin, T., Rozgonyi, T., Szepesvári, Cs. & Lőrincz, A. Self-organizing multi-resolution grid for motion planning and control 1996 International Journal of Neural Systems   article
    Abstract: A fully self-organizing neural network approach to low-dimensional control problems is desribed. We consider the problem of learning to control an object and solving the path planning problem at the same time. Control is based on the path planning model that follows the gradient of the stationary solution of a diffusion process working in the state space. Previous works are extended by introducing a self-organizing multigrid-like discretizing structure to represent the external world. Diffusion is simulated withing a recurrent neural network built on this multigrid system. The novelty of the approach is that the diffusion on the multigrid is fast. Moreover, the diffusion process on the multigrid fits well the requirements of the path planning: it accelerates the diffusion in large free space regions while still keeps the resolution in small bottleneck-like labyrinths along the path. Control is achieved in the usual way: associative learning identifies the inverse dynamics of the system in a direct fashion. To this end there are introduced interneurons between neighboring discretizing units that detect the strength of the steady-state diffusion and forward control commands to the control neurons via modifiable connections. This architecture forms the Multigrid Position-and-Direction-to-Action (MDPA) map. The architecture integrates reactive path planning and continuous motion control. It is also shown that the scheme leads to population coding for the actual command vector.
    BibTeX:
    @article{fomin96self-organizing,
      author = {T. Fomin and T. Rozgonyi and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Self-organizing multi-resolution grid for motion planning and control},
      journal = {International Journal of Neural Systems},
      year = {1996},
      volume = {7},
      pages = {757-776},
    }					
    Gábor, Z. Optimalitás őrző általánositás kockázat érzékeny döntési problémákban (Optimality saving generalization in risk-sensitive reinforcement learning) 1996 School: Eötvös Loránd University   mastersthesis
    BibTeX:
    @mastersthesis{gabor96optimalitas,
      author = {Z. G{\'a}bor},
      title = {Optimalit{\'a}s {\H{o}}rz{\H{o}} {\'a}ltal{\'a}nos{\'\i}t{\'a}s kock{\'a}zat {\'e}rz{\'e}keny d{\"o}nt{\'e}si probl{\'e}m{\'a}kban ({O}ptimality saving generalization in risk-sensitive reinforcement learning)},
      school = {E{\"o}tv{\"o}s Lor{\'a}nd University},
      year = {1996},
      address = {Budapest},
    }					
    Kovács, Sz., Tóth, G. J., Der, R. & Lőrincz, A. Output sensitive discretization for genetic algorithm with migration 1996 Neural Network World   article
    BibTeX:
    @article{kovacs96output,
      author = {{\Sz}. Kov{\'a}cs and G. J. T{\'o}th and R. Der and A. L{\H{o}}rincz},
      title = {Output sensitive discretization for genetic algorithm with migration},
      journal = {Neural Network World},
      year = {1996},
      volume = {6},
      pages = {101--107},
    }					
    Marczell, Zs., Kalmár, Zs. & Lőrincz, A. Generalized skeleton formation for texture segmentation 1996 Neural Network World   article
    BibTeX:
    @article{marczell96generalized,
      author = {{\Zs}. Marczell and {\Zs}. Kalm{\'a}r and A. L{\H{o}}rincz},
      title = {Generalized skeleton formation for texture segmentation},
      journal = {Neural Network World},
      year = {1996},
      volume = {6},
      pages = {79-87},
    }					
    Rozgonyi, T., Balázs, L., Fomin, T. & Lőrincz, A. Self-organized formation of a set of scaling filters and their neighbouring connections 1996 Biological Cybernetics   article
    BibTeX:
    @article{rozgonyi96self-organized,
      author = {T. Rozgonyi and L. Bal{\'a}zs and T. Fomin and A. L{\H{o}}rincz},
      title = {Self-organized formation of a set of scaling filters and their neighbouring connections},
      journal = {Biological Cybernetics},
      year = {1996},
      volume = {75},
      pages = {37-47},
    }					
    Space, B., Rabitz, H., Lőrincz, A. & Moore, P. Feasibility of using photophoresis to create a concentration gradient of solvated molecules 1996 Journal of Chemical Physics   article
    BibTeX:
    @article{space96feasibility,
      author = {B. Space and H. Rabitz and A. L{\H{o}}rincz and P. Moore},
      title = {Feasibility of using photophoresis to create a concentration gradient of solvated molecules},
      journal = {Journal of Chemical Physics},
      year = {1996},
      volume = {105},
      pages = {9515-9524},
    }					
    Szepesvári, Cs. & Lőrincz, A. Approximate Geometry Representations and Sensory Fusion 1996 Neurocomputing   article
    BibTeX:
    @article{szepesvari96approximate,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Approximate Geometry Representations and Sensory Fusion},
      journal = {Neurocomputing},
      year = {1996},
      volume = {12},
      pages = {267-287},
    }					
    Szepesvári, Cs. & Lőrincz, A. Inverse dynamics controllers for robust control: Consequences for neurocontrollers 1996 Proceedings of ICANN'96   inproceedings
    BibTeX:
    @inproceedings{szepesvari96inverse,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Inverse dynamics controllers for robust control: Consequences for neurocontrollers},
      booktitle = {Proceedings of ICANN'96},
      year = {1996},
      pages = {697-702},
      address = {Bochum},
    }					
    Szepesvári, Cs. & Lőrincz, A. Neurocontrol I: Self-organizing speed-field tracking 1996 Neural Network World   article
    Abstract: The problems of controlling a plant while avoiding obstacles and experiencing perturbations in the plants dynamics are considered. It is assumed that the plant's dynamics is not known in advance. To solve this problem a self-organizing artificial neural network (ANN) solution is advanced here. The ANN consists of various parts. The first part discretizes the state space of the plant and also learns the geometry of the state space. The learnt geometrical relations are represented by lateral connections. These connections are utilized for planning a speed field, allowing collision free motion. The speed field is defined over the neural represention of the state space and is transformed into control signals with the help of interneurons associated with the lateral connections: connections between interneurons and control neurons encode the inverse dynamics of the plant. These connections are learnt during a direct system inverse identification process by Hebbian learning. Theoretical results and computer experiments show the robustness of approach.
    BibTeX:
    @article{szepesvari96neurocontrol-I,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Neurocontrol {I}: Self-organizing speed-field tracking},
      journal = {Neural Network World},
      year = {1996},
      volume = {6},
      pages = {875-896},
    }					
    Szepesvári, Cs. & Lőrincz, A. Neurocontrol II: High precision control achieved using approximate inverse dynamics models 1996 Neural Network World   article
    BibTeX:
    @article{szepesvari96neurocontrol-II,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Neurocontrol {II}: High precision control achieved using approximate inverse dynamics models},
      journal = {Neural Network World},
      year = {1996},
      volume = {6},
      pages = {897-920},
    }					
    Tavitian, S., Fomin, T. & Lőrincz, A. Stabilizing competitive learning during on-line training with an anti-Hebbian weight modulation 1996 Proceedings of ICANN'96   inproceedings
    BibTeX:
    @inproceedings{tavitian96stabilizing,
      author = {S. Tavitian and T. Fomin and A. L{\H{o}}rincz},
      title = {Stabilizing competitive learning during on-line training with an anti-{Hebbian} weight modulation},
      booktitle = {Proceedings of ICANN'96},
      year = {1996},
      pages = {791-796},
      address = {Bochum},
    }					
    Amstrup, B., Szabó, G., Sauerbey, R. & Lőrincz, A. Chirped pulse control of CsI fragmentation: an experimental possibility 1995 Chemical Physics   article
    Abstract: The strength of chirped pulse optimal control as an experimental possibility is demonstrated in this paper. The suggested experiment is a pump-dump experiment that first creates an unstable - dissociating - molecule on a repulsive level and then stops fragmentation. The experiment is envisioned by using a start pulse (a doubled green pulse) that inverts the population. The control pulse - that stops the fragmentation - is the chirp optimized green pulse itself. Optimization includes second and third order chirp expansion terms. Optimization is made for the weak and strong field limits with the help of the simulated annealing method. Weak field optimization shows the expected red chirp results. Strong field optimization, on the other hand, gives rise to blue chirp as optimal solution. It is argued, that the blue chirp is the consequence of the need for locking the upper and lower state wavefunctions for efficient population inversion.
    BibTeX:
    @article{amstrup95chirped,
      author = {B. Amstrup and G. Szab{\'o} and R. Sauerbey and A. L{\H{o}}rincz},
      title = {Chirped pulse control of {CsI} fragmentation: an experimental possibility},
      journal = {Chemical Physics},
      year = {1995},
      volume = {188},
      pages = {87-97},
    }					
    Amstrup, B., Tóth, G. J., Szabó, G., Rabitz, H. & Lőrincz, A. Genetic algorithm with migration on topology conserving maps for optimal control of quantum systems 1995 J. Physical Chemistry   article
    BibTeX:
    @article{amstrup95genetic,
      author = {B. Amstrup and G. J. T{\'o}th and G. Szab{\'o} and H. Rabitz and A. L{\H{o}}rincz},
      title = {Genetic algorithm with migration on topology conserving maps for optimal control of quantum systems},
      journal = {J. Physical Chemistry},
      year = {1995},
      volume = {99},
      pages = {5206-5213},
    }					
    Amstrup, B., Tóth, G. J., Rabitz, H. & Lőrincz, A. Identification of Born-Oppenheimer potential energy surfaces of diatomic molecules from optimized chirped pulses 1995 Chemical Physics   article
    BibTeX:
    @article{amstrup95identification,
      author = {B. Amstrup and G. J. T{\'o}th and H. Rabitz and A. L{\H{o}}rincz},
      title = {Identification of {Born-Oppenheimer} potential energy surfaces of diatomic molecules from optimized chirped pulses},
      journal = {Chemical Physics},
      year = {1995},
      volume = {201},
      pages = {95-105},
    }					
    Kalmár, Zs., Szepesvári, Cs. & Lőrincz, A. Generalized Dynamic Concept model as a route to construct adaptive autonomous agents 1995 Neural Network World   article
    Abstract: A model of adaptive autonomous agents, that (i) builds internal representation of events and event relations, (ii) utilizes activation spreading for building dynamic concepts and (iii) makes use of the winner-take-all paradigm to come to a decision is extended by introducing generalization into the model. The generalization reduces memory requirements and improves performance in unseen scenes as it is indicated by computer simulations.
    BibTeX:
    @article{kalmar95generalized,
      author = {{\Zs}. Kalm{\'a}r and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Generalized Dynamic Concept model as a route to construct adaptive autonomous agents},
      journal = {Neural Network World},
      year = {1995},
      volume = {5},
      pages = {353-360},
    }					
    Tóth, G. J., Kovács, Sz. & Lőrincz, A. Genetic algorithm with alphabet optimization 1995 Biological Cybernetics   article
    BibTeX:
    @article{toth95genetic,
      author = {G. J. T{\'o}th and {\Sz}. Kov{\'a}cs and A. L{\H{o}}rincz},
      title = {Genetic algorithm with alphabet optimization},
      journal = {Biological Cybernetics},
      year = {1995},
      volume = {73},
      pages = {61-68},
    }					
    Tóth, G. J. & Lőrincz, A. Genetic algorithm with migration on a topology conserving map 1995 Neural Network World   article
    BibTeX:
    @article{toth95genetic2,
      author = {G. J. T{\'o}th and A. L{\H{o}}rincz},
      title = {Genetic algorithm with migration on a topology conserving map},
      journal = {Neural Network World},
      year = {1995},
      volume = {5},
      pages = {171-181},
    }					
    Favier, J. P., Buijs, J., Miklós, A., Lőrincz, A. & Bicanic, D. Photoacoustic characterization of different food samples 1994 Z. Lebensmittel   article
    BibTeX:
    @article{favier94photoacoustic,
      author = {J. P. Favier and J. Buijs and A. Mikl{\'o}s and A. L{\H{o}}rincz and D. Bicanic},
      title = {Photoacoustic characterization of different food samples},
      journal = {Z. Lebensmittel},
      year = {1994},
      volume = {199},
      pages = {59-63},
    }					
    Fomin, T. & Lőrincz, A. Robustness of Hebbian and anti-Hebbian networks 1994 Neural Network World   article
    BibTeX:
    @article{fomin94robustness,
      author = {T. Fomin and A. L{\H{o}}rincz},
      title = {Robustness of {Hebbian} and anti-{Hebbian} networks},
      journal = {Neural Network World},
      year = {1994},
      volume = {4},
      pages = {699-717},
    }					
    Fomin, T., Szepesvári, Cs. & Lőrincz, A. Self-organizing neurocontrol 1994 Proceedings of IEEE WCCI ICNN'94   inproceedings
    BibTeX:
    @inproceedings{fomin94self-organizing,
      author = {T. Fomin and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Self-organizing neurocontrol},
      booktitle = {Proceedings of IEEE WCCI ICNN'94},
      year = {1994},
      volume = {5},
      pages = {2777--2780},
      address = {Orlando, Florida},
      month = {June},
    }					
    Kalmár, Zs., Szepesvári, Cs. & Lőrincz, A. Generalization in an autonomous agent 1994 Proceedings of IEEE WCCI ICNN'94   inproceedings
    Abstract: In this article we present an extension of a previously defined model [8]. This model was introduced to govern an agent in a goal-programmed fashion in a previously unknown environment. The extension allows generalization in the input space, which reduces the memory requirements as well as the time requirements of the algorithm.
    BibTeX:
    @inproceedings{kalmar94generalization,
      author = {{\Zs}. Kalm{\'a}r and {\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Generalization in an autonomous agent},
      booktitle = {Proceedings of IEEE WCCI ICNN'94},
      year = {1994},
      volume = {3},
      pages = {1815--1817},
      address = {Orlando, Florida},
      month = {June},
    }					
    Rozgonyi, T. & Lőrincz, A. Possibility of detecting Davydov solitons using transient reflectivity measurements 1994 J. Applied Physics   article
    BibTeX:
    @article{rozgonyi94possibility,
      author = {T. Rozgonyi and A. L{\H{o}}rincz},
      title = {Possibility of detecting Davydov solitons using transient reflectivity measurements},
      journal = {J. Applied Physics},
      year = {1994},
      volume = {75},
      pages = {1861-1868},
    }					
    Rozgonyi, T., Fomin, T. & Lőrincz, A. Self-organizing scaling filters for image segmentation 1994 Proceedings of IEEE WCCI ICNN'94   inproceedings
    BibTeX:
    @inproceedings{rozgonyi94self-organizing,
      author = {T. Rozgonyi and T. Fomin and A. L{\H{o}}rincz},
      title = {Self-organizing scaling filters for image segmentation},
      booktitle = {Proceedings of IEEE WCCI ICNN'94},
      year = {1994},
      volume = {7},
      pages = {4380--4383},
      address = {Orlando, Florida},
      month = {June},
    }					
    Seres, I., Marczell, Zs., Fomin, T., Kovács, I. & Lőrincz, A. Modeling spatial filters of primary visual cortex 1994 IEEE International Conference on Neural Networks (ICNN)   inproceedings
    Abstract: Here we address the issue of unsupervised learning for primary visual cortex (V1) formation. According to the most popular model, single cells in the primary visual cortex are spatio-temporal filters. Receptive fields of simple cells can be subdivided into separate excitatory and inhibitory regions, which can be described by a Gaussian-weighted sine wave. These cells transform the fairly broadband input, arriving from lower visual areas, into bandlimited information in the orientation, spatial frequency and temporal frequency domains. The existence of relatively independent spatial frequency and orientation selective channels in the visual system has been shown by human psychophysics. Inhibitory interactions between neighbouring channels were suggested to perform more complex image-analysis, like texture processing or detecting long and smooth contours. Our goal is to introduce a model that imposes minimal assumptions and beyond producing spatial filters can account for some psychophysical results with the help of nonlinearities. Efforts to design self-organizing neurocontrol led to spatial filters. Here, we shall try to identify these filters with the local filters of V1.
    BibTeX:
    @inproceedings{seres94modeling,
      author = {I. Seres and {\Zs}. Marczell and T. Fomin and I. Kov{\'a}cs and A. L{\H{o}}rincz},
      title = {Modeling spatial filters of primary visual cortex},
      booktitle = {IEEE International Conference on Neural Networks (ICNN)},
      year = {1994},
      pages = {2282-2284},
      doi = {http://dx.doi.org/10.1109/ICNN.1994.374574},
    }					
    Szakács, T., Amstrup, B., Gross, P., Kosloff, R., Rabitz, H. & Lőrincz, A. Locking a molecular bond: A case study of CsI 1994 Physical Review A   article
    BibTeX:
    @article{szakacs94locking,
      author = {T. Szak{\'a}cs and B. Amstrup and P. Gross and R. Kosloff and H. Rabitz and A. L{\H{o}}rincz},
      title = {Locking a molecular bond: A case study of {CsI}},
      journal = {Physical Review A},
      year = {1994},
      volume = {50},
      pages = {2540-2547},
    }					
    Szepesvári, Cs. & Lőrincz, A. Behavior of an adaptive autonomous agent working with cues and competing concepts 1994 Adaptive Behavior   article
    BibTeX:
    @article{szepesvari94behavior,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Behavior of an adaptive autonomous agent working with cues and competing concepts},
      journal = {Adaptive Behavior},
      year = {1994},
      volume = {2},
      pages = {131-160},
    }					
    Szepesvári, Cs. & Lőrincz, A. Self-organized learning of 3 dimensions 1994 Proceedings of IEEE WCCI ICNN'94   inproceedings
    BibTeX:
    @inproceedings{szepesvari94self,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Self-organized learning of 3 dimensions},
      booktitle = {Proceedings of IEEE WCCI ICNN'94},
      year = {1994},
      volume = {2},
      pages = {671--674},
      address = {Orlando, Florida},
      month = {June},
    }					
    Szepesvári, Cs., Balázs, L. & Lőrincz, A. Topology learning solved by extended objects: a neural network model 1994 Neural Computation   article
    BibTeX:
    @article{szepesvari94topology,
      author = {{\Cs}. Szepesv{\'a}ri and L. Bal{\'a}zs and A. L{\H{o}}rincz},
      title = {Topology learning solved by extended objects: a neural network model},
      journal = {Neural Computation},
      year = {1994},
      volume = {6},
      pages = {439-456},
    }					
    Tóth, G. J., Lőrincz, A. & Rabitz, H. The effect of control field and measurement imprecision on laboratory feedback control of quantum systems 1994 J. Chemical Physics   article
    BibTeX:
    @article{toth94effect,
      author = {G. J. T{\'o}th and A. L{\H{o}}rincz and H. Rabitz},
      title = {The effect of control field and measurement imprecision on laboratory feedback control of quantum systems},
      journal = {J. Chemical Physics},
      year = {1994},
      volume = {101},
      pages = {3715-3722},
    }					
    Bakos, J. S., Ignácz, P. N., Lőrincz, A., Sörlei, Zs. & Szigeti, J. Measurement of the vibrational relaxation rate of molecules relevant to the environmental photoacoustic measurements 1993 Appl. Phys. B   article
    BibTeX:
    @article{bakos93measurement,
      author = {J. S. Bakos and P. N. Ign{\'a}cz and A. L{\H{o}}rincz and {\Zs}. S{\"o}rlei and J. Szigeti},
      title = {Measurement of the vibrational relaxation rate of molecules relevant to the environmental photoacoustic measurements},
      journal = {Appl. Phys. B},
      year = {1993},
      volume = {57},
      pages = {89-93},
    }					
    Amstrup, B., Doll, J. D., Sauerbrey, R. A., Szabó, G. & Lőrincz, A. Optimal control of quantum systems by chirped pulses 1993 Phys. Rev. A   article
    BibTeX:
    @article{doll93optimal,
      author = {B. Amstrup and J. D. Doll and R. A. Sauerbrey and G. Szab{\'o} and A. L{\H{o}}rincz},
      title = {Optimal control of quantum systems by chirped pulses},
      journal = {Phys. Rev. A},
      year = {1993},
      volume = {48},
      pages = {3830-3836},
    }					
    Amstrup, B., Lőrincz, A. & Rice, S. A. Population inversion in a multilevel system: A model study 1993 J. Phys. Chem.   article
    BibTeX:
    @article{doll93population,
      author = {B. Amstrup and A. L{\H{o}}rincz and S. A. Rice},
      title = {Population inversion in a multilevel system: A model study},
      journal = {J. Phys. Chem.},
      year = {1993},
      volume = {97},
      pages = {6175-6183},
    }					
    Szakács, T., Lucza, T. & Lőrincz, A. Optimal control of quantum systems on metallic surfaces 1993 Surface Science   article
    BibTeX:
    @article{szakacs93optimal,
      author = {T. Szak{\'a}cs and T. Lucza and A. L{\H{o}}rincz},
      title = {Optimal control of quantum systems on metallic surfaces},
      journal = {Surface Science},
      year = {1993},
      volume = {296},
      pages = {251-260},
    }					
    Szakács, T., Somlói, J. & Lőrincz, A. Optimization of harmonic oscillator wavefunction squeezing in pulsed electronic transitions 1993 Chem. Phys.   article
    BibTeX:
    @article{szakacs93optimization,
      author = {T. Szak{\'a}cs and J. Soml{\'o}i and A. L{\H{o}}rincz},
      title = {Optimization of harmonic oscillator wavefunction squeezing in pulsed electronic transitions},
      journal = {Chem. Phys.},
      year = {1993},
      volume = {172},
      pages = {1-6},
    }					
    Szepesvári, Cs. & Lőrincz, A. Integration of artificial neural networks and dynamic concepts to an adaptive self-organizing agent 1993 World Congress on Neural Networks '93   inproceedings
    BibTeX:
    @inproceedings{szepesvari93integration,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Integration of artificial neural networks and dynamic concepts to an adaptive self-organizing agent},
      booktitle = {World Congress on Neural Networks '93},
      year = {1993},
      volume = {3},
      pages = {524-527},
      address = {Portland, Oregon, USA},
      month = {11-15~July},
      note = {Lawrence Erlbaum Associates, Inc. Publishers, New Jersey},
    }					
    Szepesvári, Cs. & Lőrincz, A. Integration of ANN cues, dynamic AI concepts and ANN decision system into an adaptive self-organizing agent 1993 Third Conf. on Artificial Intelligence   inproceedings
    BibTeX:
    @inproceedings{szepesvari93integrationANN-AI,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Integration of {ANN} cues, dynamic {AI} concepts and {ANN} decision system into an adaptive self-organizing agent},
      booktitle = {Third Conf. on Artificial Intelligence},
      year = {1993},
      editor = {P. Koch},
      pages = {231-237},
      month = {6-8~April},
      organization = {John von Neumann Society for Computer Sciences},
    }					
    Szepesvári, Cs. & Lőrincz, A. Topology learning solved by extended objects: A neural network model 1993 World Congress on Neural Networks '93   inproceedings
    BibTeX:
    @inproceedings{szepesvari93topology,
      author = {{\Cs}. Szepesv{\'a}ri and A. L{\H{o}}rincz},
      title = {Topology learning solved by extended objects: A neural network model},
      booktitle = {World Congress on Neural Networks '93},
      year = {1993},
      volume = {3},
      pages = {497-500},
      address = {Portland, Oregon, USA},
      month = {11-15~July},
      note = {Lawrence Erlbaum Associates, Inc. Publishers, New Jersey},
    }					
    Tóth, G. J. & Lőrincz, A. Genetic algorithm with migration on topology conserving maps 1993 World Congress on Neural Networks '93   inproceedings
    BibTeX:
    @inproceedings{toth93genetic,
      author = {G. J. T{\'o}th and A. L{\H{o}}rincz},
      title = {Genetic algorithm with migration on topology conserving maps},
      booktitle = {World Congress on Neural Networks '93},
      year = {1993},
      volume = {3},
      pages = {168-171},
      address = {Portland, Oregon, USA},
      month = {11-15~July},
      note = {Lawrence Erlbaum Associates, Inc. Publishers, New Jersey},
    }					
    Tóth, G. J., Szakács, T. & Lőrincz, A. Simulation of pulsed laser material processing controlled by an extended self-organizing Kohonen feature map 1993 World Congress on Neural Networks '93   inproceedings
    BibTeX:
    @inproceedings{toth93simulation,
      author = {G. J. T{\'o}th and T. Szak{\'a}cs and A. L{\H{o}}rincz},
      title = {Simulation of pulsed laser material processing controlled by an extended self-organizing Kohonen feature map},
      booktitle = {World Congress on Neural Networks '93},
      year = {1993},
      volume = {3},
      pages = {127-130},
      address = {Portland, Oregon, USA},
      month = {11-15~July},
      note = {Lawrence Erlbaum Associates, Inc. Publishers, New Jersey},
    }					
    Tóth, G. J., Szakács, T. & Lőrincz, A. Simulation of pulsed laser material processing controlled by an extended self-organising Kohonen feature map 1993 Mat. Sci. Engin. B   article
    BibTeX:
    @article{toth93simulation2,
      author = {G. J. T{\'o}th and T. Szak{\'a}cs and A. L{\H{o}}rincz},
      title = {Simulation of pulsed laser material processing controlled by an extended self-organising {Kohonen} feature map},
      journal = {Mat. Sci. Engin. B},
      year = {1993},
      volume = {18},
      pages = {281-288},
    }					
    Csanádi, M. & Lőrincz, A. Neural network formalization of the Hungarian party-state system 1992 Behavioral Science   article
    BibTeX:
    @article{csanadi92neural,
      author = {M. Csan{\'a}di and A. L{\H{o}}rincz},
      title = {Neural network formalization of the {Hungarian} party-state system},
      journal = {Behavioral Science},
      year = {1992},
      volume = {37},
      pages = {81-108},
    }					
    Lőrincz, A., Bakker, R. A., Miklós, A. & Somlói, J. Femtosecond thermoreflectivity 1992 Springer Series in Optical Sciences Vol. 69, Photoacoustic and Photothermal Phenomena III   inproceedings
    BibTeX:
    @inproceedings{lorincz92femtosecond,
      author = {A. L{\H{o}}rincz and R. A. Bakker and A. Mikl{\'o}s and J. Soml{\'o}i},
      title = {Femtosecond thermoreflectivity},
      booktitle = {Springer Series in Optical Sciences Vol. 69, Photoacoustic and Photothermal Phenomena III},
      year = {1992},
      editor = {D. Bicanic},
      pages = {257-262},
      address = {Berlin},
      publisher = {Springer-Verlag},
      note = {invited},
    }					
    Lőrincz, A. & Dóka, O. Photorefractive lock-in amplifier and thermal wave microscope 1992 Springer Series in Optical Sciences Vol. 69, Photoacoustic and Photothermal Phenomena III   inproceedings
    BibTeX:
    @inproceedings{lorincz92photorefractive,
      author = {A. L{\H{o}}rincz and O. D{\'o}ka},
      title = {Photorefractive lock-in amplifier and thermal wave microscope},
      booktitle = {Springer Series in Optical Sciences Vol. 69, Photoacoustic and Photothermal Phenomena III},
      year = {1992},
      editor = {D. Bicanic},
      pages = {603-604},
      address = {Berlin},
      publisher = {Springer-Verlag},
    }					
    Somlói, J. & Lőrincz, A. Dynamic spectra of a two-electronic-surface molecule 1992 Spectrochimica Acta A   article
    BibTeX:
    @article{somloi92dynamic,
      author = {J. Soml{\'o}i and A. L{\H{o}}rincz},
      title = {Dynamic spectra of a two-electronic-surface molecule},
      journal = {Spectrochimica Acta A},
      year = {1992},
      volume = {48},
      pages = {77-86},
    }					
    Szakács, T. & Lőrincz, A. Pulsed laser machining by training artificial neural networks with the help of the thermal diffusion equation 1992 Springer Series in Optical Sciences Vol. 69, Photoacoustic and Photothermal Phenomena III   inproceedings
    BibTeX:
    @inproceedings{szakacs92pulsed,
      author = {T. Szak{\'a}cs and A. L{\H{o}}rincz},
      title = {Pulsed laser machining by training artificial neural networks with the help of the thermal diffusion equation},
      booktitle = {Springer Series in Optical Sciences Vol. 69, Photoacoustic and Photothermal Phenomena III},
      year = {1992},
      editor = {D. Bicanic},
      pages = {610-613},
      address = {Berlin},
      publisher = {Springer-Verlag},
    }					
    Angeli, Gy. Z., Bozóki, Z., Miklós, A., Lőrincz, A., Thöny, A. & Sigrist, M. W. Design and characterization of a windowless resonant photoacoustic chamber equipped with resonance locking circuitry 1991 Rev. Sci. Instr.   article
    BibTeX:
    @article{angeli91design,
      author = {{\Gy}. Z. Angeli and Z. Boz{\'o}ki and A. Mikl{\'o}s and A. L{\H{o}}rincz and A. Th{\"o}ny and M. W. Sigrist},
      title = {Design and characterization of a windowless resonant photoacoustic chamber equipped with resonance locking circuitry},
      journal = {Rev. Sci. Instr.},
      year = {1991},
      volume = {62},
      pages = {810-815},
    }					
    Angeli, Gy. Z., Miklós, A. & Lőrincz, A. Photoacoustic Spectroscopy I: New analytical method for environmental trace gas analysis 1991 Acta Chim. Hung.   article
    BibTeX:
    @article{angeli91photoacoustic,
      author = {{\Gy}. Z. Angeli and A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Photoacoustic Spectroscopy {I}: New analytical method for environmental trace gas analysis},
      journal = {Acta Chim. Hung.},
      year = {1991},
      volume = {128},
      pages = {877-889},
    }					
    Dóka, O., Kispéter, J. & Lőrincz, A. Determination of iron content of milk protein concentrates through photoacoustic spectroscopy 1991 J. Dairy Res.   article
    BibTeX:
    @article{doka91determination,
      author = {O. D{\'o}ka and J. Kisp{\'e}ter and A. L{\H{o}}rincz},
      title = {Determination of iron content of milk protein concentrates through photoacoustic spectroscopy},
      journal = {J. Dairy Res.},
      year = {1991},
      volume = {58},
      pages = {453-460},
    }					
    Dóka, O., Kaszás, G. & Lőrincz, A. High sensitivity cell for measurement of photoacoustic spectra of powders 1991 Acta Ovariensis   article
    BibTeX:
    @article{doka91high,
      author = {O. D{\'o}ka and G. Kasz{\'a}s and A. L{\H{o}}rincz},
      title = {High sensitivity cell for measurement of photoacoustic spectra of powders},
      journal = {Acta Ovariensis},
      year = {1991},
      volume = {34},
      pages = {39-46},
    }					
    Favier, J., Buijs, J., Dóka, O. & Lőrincz, A. Photoacoustic measurements of flours for application in quality control 1991 Conf. Digest of STIMPAP   inproceedings
    BibTeX:
    @inproceedings{favier91photoacoustic,
      author = {J. Favier and J. Buijs and O. D{\'o}ka and A. L{\H{o}}rincz},
      title = {Photoacoustic measurements of flours for application in quality control},
      booktitle = {Conf. Digest of STIMPAP},
      year = {1991},
      pages = {68-69},
      address = {Doorwerth, The Netherlands},
    }					
    Lőrincz, A., Bozóki, Z. & Miklós, A. Comments on electron relaxation time measurements from transient reflectances of metals 1991 J. Appl. Phys.   article
    BibTeX:
    @article{lorincz91comments,
      author = {A. L{\H{o}}rincz and Z. Boz{\'o}ki and A. Mikl{\'o}s},
      title = {Comments on electron relaxation time measurements from transient reflectances of metals},
      journal = {J. Appl. Phys.},
      year = {1991},
      volume = {70},
      pages = {941-945},
    }					
    Lőrincz, A., Bakker, R. A., Miklós, A. & Somlói, J. Femtosecond Thermoreflectivity 1991 Conf. Digest of STIMPAP   inproceedings
    BibTeX:
    @inproceedings{lorincz91femtosecond,
      author = {A. L{\H{o}}rincz and R. A. Bakker and A. Mikl{\'o}s and J. Soml{\'o}i},
      title = {Femtosecond Thermoreflectivity},
      booktitle = {Conf. Digest of STIMPAP},
      year = {1991},
      pages = {1-10},
      address = {Doorwerth, The Netherlands},
      note = {invited},
    }					
    Lőrincz, A. Optical procedure and equipment using the imaging of phase information for the investigation of material quality 1991 Patent   misc
    BibTeX:
    @misc{lorincz91optical_patent,
      author = {A. L{\H{o}}rincz},
      title = {Optical procedure and equipment using the imaging of phase information for the investigation of material quality},
      journal = {Patent},
      year = {1991},
      note = {Patent number (`Lajstromsz{\'a}m'): 202987/1991},
    }					
    Lőrincz, A. Optical procedure and equipment for the investigation of material quality 1991 Patent   misc
    BibTeX:
    @misc{lorincz91optical2_patent,
      author = {A. L{\H{o}}rincz},
      title = {Optical procedure and equipment for the investigation of material quality},
      journal = {Patent},
      year = {1991},
      note = {Patent number (`Lajstromsz{\'a}m'): 202988/1991},
    }					
    Lőrincz, A. & Dóka, O. Photorefractive lock-in amplifier and thermal wave microscope 1991 Conf. Digest of STIMPAP   inproceedings
    BibTeX:
    @inproceedings{lorincz91photorefractive,
      author = {A. L{\H{o}}rincz and O. D{\'o}ka},
      title = {Photorefractive lock-in amplifier and thermal wave microscope},
      booktitle = {Conf. Digest of STIMPAP},
      year = {1991},
      pages = {268-269},
      address = {Doorwerth, The Netherlands},
    }					
    Lőrincz, A. & Miklós, A. Ultrafast Phenomena (Chapter V) 1991 Progress in Photothermal and Photoacoustic Science and Technology   inproceedings
    BibTeX:
    @inproceedings{lorincz91principles,
      author = {A. L{\H{o}}rincz and A. Mikl{\'o}s},
      title = {Ultrafast Phenomena ({C}hapter {V})},
      booktitle = {Progress in Photothermal and Photoacoustic Science and Technology},
      year = {1991},
      editor = {A. Mandelis},
      volume = {1},
      pages = {429-490},
      address = {Amsterdam},
      publisher = {Elsevier},
      note = {Principles and Perspectives of Photothermal and Photoacoustic Phenomena},
    }					
    Lőrincz, A. & Várkonyi, A. Procedure and equipment for the optical investigation of surface smoothness 1991 Patent   misc
    BibTeX:
    @misc{lorincz91procedure_patent,
      author = {A. L{\H{o}}rincz and A. V{\'a}rkonyi},
      title = {Procedure and equipment for the optical investigation of surface smoothness},
      journal = {Patent},
      year = {1991},
      note = {Patent number (`Lajstromsz{\'a}m'): 204339/1991},
    }					
    Lőrincz, A. & Miklós, A. Procedure and equipment for the photoacoustic measurement of gas composition 1991 Patent   misc
    BibTeX:
    @misc{lorincz91procedure2_patent,
      author = {A. L{\H{o}}rincz and A. Mikl{\'o}s},
      title = {Procedure and equipment for the photoacoustic measurement of gas composition},
      journal = {Patent},
      year = {1991},
      note = {Patent number (`Lajstromsz{\'a}m'): 203153/1991},
    }					
    Lőrincz, A., Miklós, A. & Várkonyi, A. Procedure and equipment for the photoacoustic local measurement of material quality 1991 Patent   misc
    BibTeX:
    @misc{lorincz91procedure3_patent,
      author = {A. L{\H{o}}rincz and A. Mikl{\'o}s and A. V{\'a}rkonyi},
      title = {Procedure and equipment for the photoacoustic local measurement of material quality},
      journal = {Patent},
      year = {1991},
      note = {Patent number (`Lajstromsz{\'a}m'): 203408/1991},
    }					
    Lőrincz, A. Procedure and equipment for the measurement of material quality via changes of reflexion or transmission upon light absorption 1991 Patent   misc
    BibTeX:
    @misc{lorincz91procedure4_patent,
      author = {A. L{\H{o}}rincz},
      title = {Procedure and equipment for the measurement of material quality via changes of reflexion or transmission upon light absorption},
      journal = {Patent},
      year = {1991},
      note = {Patent number (`Lajstromsz{\'a}m'): 203409/1991},
    }					
    Miklós, A., Bozóki, Z. & Lőrincz, A. An improved theory of photoacoustic signal generation in gases and fluids 1991 Physical Acoustics; Fundamental and Applied   inproceedings
    BibTeX:
    @inproceedings{miklos91improved,
      author = {A. Mikl{\'o}s and Z. Boz{\'o}ki and A. L{\H{o}}rincz},
      title = {An improved theory of photoacoustic signal generation in gases and fluids},
      booktitle = {Physical Acoustics; Fundamental and Applied},
      year = {1991},
      editor = {O. Leroy},
      pages = {511-516},
      address = {New York},
      publisher = {Plenum Press},
    }					
    Sólyom, A., Miklós, A., Angeli, Gy. Z. & Lőrincz, A. Photoacoustic Spectroscopy II: New instrument for continuous monitoring of environmental trace gases 1991 Acta Chim. Hung.   article
    BibTeX:
    @article{solyom91photoacoustic,
      author = {A. S{\'o}lyom and A. Mikl{\'o}s and {\Gy}. Z. Angeli and A. L{\H{o}}rincz},
      title = {Photoacoustic Spectroscopy {II}: New instrument for continuous monitoring of environmental trace gases},
      journal = {Acta Chim. Hung.},
      year = {1991},
      volume = {128},
      pages = {891-900},
    }					
    Somlói, J., Bakker, R. A. & Lőrincz, A. Femtosecond thermoreflectivity of metals in the hydrodynamic approximation 1991 Z. Phys.   article
    BibTeX:
    @article{somloi91femtosecond,
      author = {J. Soml{\'o}i and R. A. Bakker and A. L{\H{o}}rincz},
      title = {Femtosecond thermoreflectivity of metals in the hydrodynamic approximation},
      journal = {Z. Phys.},
      year = {1991},
      volume = {84},
      pages = {361-367},
    }					
    Somlói, J. & Lőrincz, A. Two-electron-state molecules under femtosecond excitations 1991 33rd IUPAC Congress   inproceedings
    BibTeX:
    @inproceedings{somloi91two-electron,
      author = {J. Soml{\'o}i and A. L{\H{o}}rincz},
      title = {Two-electron-state molecules under femtosecond excitations},
      booktitle = {33rd IUPAC Congress},
      year = {1991},
      address = {Budapest, Hungary},
      month = {17-22~August},
      note = {\#2071},
    }					
    Somlói, J. & Lőrincz, A. Two-electron-surface molecule in strong electric fields 1991 Phys. Rev. A   article
    BibTeX:
    @article{somloi91two-electron2,
      author = {J. Soml{\'o}i and A. L{\H{o}}rincz},
      title = {Two-electron-surface molecule in strong electric fields},
      journal = {Phys. Rev. A},
      year = {1991},
      volume = {43},
      pages = {2397-2382},
    }					
    Strausz, Gy. & Lőrincz, A. Image reconstruction with connectionist machine 1991 Proceedings of the International Digital Signal Processing Conf.   inproceedings
    BibTeX:
    @inproceedings{strausz91image,
      author = {{\Gy}. Strausz and A. L{\H{o}}rincz},
      title = {Image reconstruction with connectionist machine},
      booktitle = {Proceedings of the International Digital Signal Processing Conf.},
      year = {1991},
      pages = {531-540},
      address = {Berlin, Germany},
    }					
    Strausz, Gy., Fehér, S. & Lőrincz, A. Integration of AI and the neural network concept 1991 Proceedings of the Conf. on Intelligent Systems,   inproceedings
    BibTeX:
    @inproceedings{strausz91integration,
      author = {{\Gy}. Strausz and S. Feh{\'e}r and A. L{\H{o}}rincz},
      title = {Integration of {AI} and the neural network concept},
      booktitle = {Proceedings of the Conf. on Intelligent Systems,},
      year = {1991},
      editor = {A. Gy{\"o}rgy},
      pages = {109-119},
      address = {Veszpr{\'e}m, Hungary},
      month = {25-27~September},
    }					
    Szakács, T. & Lőrincz, A. Pulsed laser machining by training artificial neural networks with the help of thermal diffusion equation 1991 Conf. Digest of STIMPAP   inproceedings
    BibTeX:
    @inproceedings{szakacs91pulsed,
      author = {T. Szak{\'a}cs and A. L{\H{o}}rincz},
      title = {Pulsed laser machining by training artificial neural networks with the help of thermal diffusion equation},
      booktitle = {Conf. Digest of STIMPAP},
      year = {1991},
      pages = {520},
      address = {Doorwerth, The Netherlands},
    }					
    Angeli, Gy. Z., Miklós, A. & Lőrincz, A. Electronic control system of a high-Q resonant photoacoustic chamber designed for environmental trace gas analysis 1990 Proc. of Euroanalysis VII   inproceedings
    BibTeX:
    @inproceedings{angeli90electronic,
      author = {{\Gy}. Z. Angeli and A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Electronic control system of a high-{Q} resonant photoacoustic chamber designed for environmental trace gas analysis},
      booktitle = {Proc. of Euroanalysis VII},
      year = {1990},
      address = {Vienna, Austria},
      month = {26-31~August},
      note = {A1.1. P-Mo-1},
    }					
    Bozóki, Z., Miklós, A. & Lőrincz, A. Theory of picosecond transient reflectance measurement of thermal and elastic properties of thin metal films 1990 Mat. Sci. Eng. B   article
    BibTeX:
    @article{bozoki90theory,
      author = {Z. Boz{\'o}ki and A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Theory of picosecond transient reflectance measurement of thermal and elastic properties of thin metal films},
      journal = {Mat. Sci. Eng. B},
      year = {1990},
      volume = {5},
      pages = {147-150},
    }					
    Lőrincz, A. Picosecond transient thermoreflectance: A new probe of two-dimensional and quasi two-dimensional structures 1990 J. Appl. Phys   article
    BibTeX:
    @article{lorincz90picosecond,
      author = {A. L{\H{o}}rincz},
      title = {Picosecond transient thermoreflectance: A new probe of two-dimensional and quasi two-dimensional structures},
      journal = {J. Appl. Phys},
      year = {1990},
      volume = {67},
      pages = {2567-2570},
    }					
    Dóka, O., Miklós, A. & Lőrincz, A. Resolution of nonlinear thermal wave microscopes 1989 Appl. Phys. A   article
    BibTeX:
    @article{doka89resolution,
      author = {O. D{\'o}ka and A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Resolution of nonlinear thermal wave microscopes},
      journal = {Appl. Phys. A},
      year = {1989},
      volume = {48},
      pages = {415-417},
    }					
    Jin, Y., Tannor, D. J., Somlói, J. & Lőrincz, A. Optimalization procedure for population inversion with ultrashort pulses 1989 XII Midwest Theoretical Chemistry Conference   inproceedings
    BibTeX:
    @inproceedings{jin89optimalization,
      author = {Y. Jin and D. J. Tannor and J. Soml{\'o}i and A. L{\H{o}}rincz},
      title = {Optimalization procedure for population inversion with ultrashort pulses},
      booktitle = {XII Midwest Theoretical Chemistry Conference},
      year = {1989},
      pages = {2-17},
      address = {Indianapolis},
      month = {11-13~May},
    }					
    Lőrincz, A. Optical lock-in amplifier based on two-beam coupling in photorefractive media. An application: Thermal Wave Microscopy 1989 Symposium on Physics of Optical Crystals   inproceedings
    BibTeX:
    @inproceedings{lorincz89optical,
      author = {A. L{\H{o}}rincz},
      title = {Optical lock-in amplifier based on two-beam coupling in photorefractive media. An application: Thermal Wave Microscopy},
      booktitle = {Symposium on Physics of Optical Crystals},
      year = {1989},
      pages = {76},
      address = {Budapest, Hungary},
      month = {10-12~October},
    }					
    Miklós, A., Lőrincz, A. & Angeli, Gy. Z. Active photoacoustic cell for trace gas analysis 1989 Proc. of the XXVI Colloquium Spectroscopicum Internationale   inproceedings
    BibTeX:
    @inproceedings{miklos89active,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz and {\Gy}. Z. Angeli},
      title = {Active photoacoustic cell for trace gas analysis},
      booktitle = {Proc. of the XXVI Colloquium Spectroscopicum Internationale},
      year = {1989},
      address = {National Palace of Culture, Sofia, Bulgaria},
      month = {2-9~July},
    }					
    Miklós, A. & Lőrincz, A. Determination of thermal transport properties of thin metal films from pulsed thermoreflectance measurements in the picosecond regime 1989 Appl. Phys. B   article
    BibTeX:
    @article{miklos89determination,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Determination of thermal transport properties of thin metal films from pulsed thermoreflectance measurements in the picosecond regime},
      journal = {Appl. Phys. B},
      year = {1989},
      volume = {48},
      pages = {261-267},
    }					
    Miklós, A., Bozóki, Z. & Lőrincz, A. Picosecond transient reflectance of thin metal films 1989 J. Appl. Phys.   article
    BibTeX:
    @article{miklos89picosecond,
      author = {A. Mikl{\'o}s and Z. Boz{\'o}ki and A. L{\H{o}}rincz},
      title = {Picosecond transient reflectance of thin metal films},
      journal = {J. Appl. Phys.},
      year = {1989},
      volume = {66},
      pages = {2968-2972},
    }					
    Miklós, A. & Lőrincz, A. Windowless resonant acoustic chamber for trace gas analysis 1989 Proc. 13th Congress on Acoustics   inproceedings
    BibTeX:
    @inproceedings{miklos89windowless,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Windowless resonant acoustic chamber for trace gas analysis},
      booktitle = {Proc. 13th Congress on Acoustics},
      year = {1989},
      volume = {4},
      pages = {117-120},
      address = {Beograd},
      month = {24-31~August},
    }					
    Miklós, A. & Lőrincz, A. Windowless resonant acoustic chamber for laser-photoacoustic applications 1989 Appl. Phys. B   article
    BibTeX:
    @article{miklos89windowless2,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Windowless resonant acoustic chamber for laser-photoacoustic applications},
      journal = {Appl. Phys. B},
      year = {1989},
      pages = {213-218},
    }					
    Dóka, O., Bíró, T. & Lőrincz, A. High exposure dosimetry with LiF (TLD-100) by photo-acoustic spectrometry 1988 J. Phys. D.: Appl. Phys   article
    BibTeX:
    @article{doka88high,
      author = {O. D{\'o}ka and T. B{\'\i}r{\'o} and A. L{\H{o}}rincz},
      title = {High exposure dosimetry with {LiF (TLD-100)} by photo-acoustic spectrometry},
      journal = {J. Phys. D.: Appl. Phys},
      year = {1988},
      volume = {21},
      pages = {820-825},
    }					
    Dóka, O., Miklós, A. & Lőrincz, A. Signal generation in optically detecting thermal wave instruments 1988 J. Appl. Phys.   article
    BibTeX:
    @article{doka88signal,
      author = {O. D{\'o}ka and A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Signal generation in optically detecting thermal wave instruments},
      journal = {J. Appl. Phys.},
      year = {1988},
      volume = {63},
      pages = {2156-2158},
    }					
    Kelemen, A., Lőrincz, A. & Miklós, A. Procedure, equipment and sample holder for the photoacoustic investigation of transparent or non-transparent condensed samples of small or medium absorption 1988 Patent   misc
    BibTeX:
    @misc{kelemen88procedure_patent,
      author = {A. Kelemen and A. L{\H{o}}rincz and A. Mikl{\'o}s},
      title = {Procedure, equipment and sample holder for the photoacoustic investigation of transparent or non-transparent condensed samples of small or medium absorption},
      journal = {Patent},
      year = {1988},
      note = {Patent number (`Lajstromsz{\'a}m'): 193168/1988},
    }					
    Lőrincz, A. Parallel processing single-beam Fourier imaging thermal wave microscopes: Line heating systems 1988 J. Appl. Phys.   article
    BibTeX:
    @article{lorincz88parallel,
      author = {A. L{\H{o}}rincz},
      title = {Parallel processing single-beam {Fourier} imaging thermal wave microscopes: Line heating systems},
      journal = {J. Appl. Phys.},
      year = {1988},
      volume = {64},
      pages = {4342-4346},
    }					
    Lőrincz, A., Dóka, O. & Miklós, A. Resolution of thermal wave microscopes 1988 Proceedings of the 3rd Int. Symp. on Modern Optics   inproceedings
    BibTeX:
    @inproceedings{lorincz88resolution,
      author = {A. L{\H{o}}rincz and O. D{\'o}ka and A. Mikl{\'o}s},
      title = {Resolution of thermal wave microscopes},
      booktitle = {Proceedings of the 3rd Int. Symp. on Modern Optics},
      year = {1988},
      editor = {G. Lupkovics and A. Podmaniczky},
      pages = {374-379},
      address = {Budapest-Hungary},
      month = {13-16~September},
    }					
    Lőrincz, A. Resolution of thermal wave microscopes for periodic structures 1988 J. Appl. Phys.   article
    BibTeX:
    @article{lorincz88resolution2,
      author = {A. L{\H{o}}rincz},
      title = {Resolution of thermal wave microscopes for periodic structures},
      journal = {J. Appl. Phys.},
      year = {1988},
      volume = {64},
      pages = {6713-6715},
    }					
    Lőrincz, A. & Andor, L. Single-beam thermal wave microscopes 1988 Photoacoustic and Photothermal Phenomena   inproceedings
    BibTeX:
    @inproceedings{lorincz88single-beam,
      author = {A. L{\H{o}}rincz and L. Andor},
      title = {Single-beam thermal wave microscopes},
      booktitle = {Photoacoustic and Photothermal Phenomena},
      year = {1988},
      editor = {P. Hess and J. Pelzl},
      volume = {58},
      series = {Springer Ser. in Opt. Sci.},
      pages = {486-487},
      address = {Berlin, Heidelberg},
      publisher = {Springer},
    }					
    Lőrincz, A. Single-beam thermal wave microscopes based on Fourier imaging of phase information 1988 Appl. Phys. B   article
    BibTeX:
    @article{lorincz88single-beam2,
      author = {A. L{\H{o}}rincz},
      title = {Single-beam thermal wave microscopes based on {Fourier} imaging of phase information},
      journal = {Appl. Phys. B},
      year = {1988},
      volume = {47},
      pages = {35-40},
    }					
    Lőrincz, A. Spatially multiplexed single-beam Fourier imaging thermal wave microscopes 1988 Proceedings of the 3rd Int. Symp. on Modern Optics   inproceedings
    BibTeX:
    @inproceedings{lorincz88spatially,
      author = {A. L{\H{o}}rincz},
      title = {Spatially multiplexed single-beam {Fourier} imaging thermal wave microscopes},
      booktitle = {Proceedings of the 3rd Int. Symp. on Modern Optics},
      year = {1988},
      editor = {G. Lupkovics and A. Podmaniczky},
      pages = {392-397},
      address = {Budapest-Hungary},
      month = {13-16~September},
    }					
    Miklós, A. & Lőrincz, A. Theory of picosecond transient thermoreflectance measurements 1988 Proceedings of the 3rd Int. Symp. on Modern Optics   inproceedings
    BibTeX:
    @inproceedings{miklos88theory,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Theory of picosecond transient thermoreflectance measurements},
      booktitle = {Proceedings of the 3rd Int. Symp. on Modern Optics},
      year = {1988},
      editor = {G. Lupkovics and A. Podmaniczky},
      pages = {490-495},
      address = {Budapest-Hungary},
      month = {13-16~September},
    }					
    Miklós, A. & Lőrincz, A. Transient thermoreflectance of thin films in the picosecond regime 1988 Photoacoustic and Photothermal Phenomena   inproceedings
    BibTeX:
    @inproceedings{miklos88transient,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Transient thermoreflectance of thin films in the picosecond regime},
      booktitle = {Photoacoustic and Photothermal Phenomena},
      year = {1988},
      editor = {P. Hess and J. Pelzl},
      volume = {58},
      series = {Springer Ser. in Opt. Sci.},
      pages = {198-200},
      address = {Berlin, Heidelberg},
      publisher = {Springer},
    }					
    Miklós, A. & Lőrincz, A. Transient thermoreflectance of thin metal films in the picosecond regime 1988 J. Appl. Phys.   article
    BibTeX:
    @article{miklos88transient2,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Transient thermoreflectance of thin metal films in the picosecond regime},
      journal = {J. Appl. Phys.},
      year = {1988},
      volume = {63},
      pages = {2391-2395},
    }					
    Miklós, A. & Lőrincz, A. Windowless photoacoustic cell for trace gas analysis 1988 Proceedings of the 3rd Int. Symp. on Modern Optics   inproceedings
    BibTeX:
    @inproceedings{miklos88windowless,
      author = {A. Mikl{\'o}s and A. L{\H{o}}rincz},
      title = {Windowless photoacoustic cell for trace gas analysis},
      booktitle = {Proceedings of the 3rd Int. Symp. on Modern Optics},
      year = {1988},
      editor = {G. Lupkovics and A. Podmaniczky},
      pages = {380-385},
      address = {Budapest-Hungary},
      month = {13-16~September},
    }					
    Lőrincz, A. Possibility of detecting oscillations in near resonance Raman scattering 1987 Chem. Phys.   article
    BibTeX:
    @article{lorincz87possibility,
      author = {A. L{\H{o}}rincz},
      title = {Possibility of detecting oscillations in near resonance {Raman} scattering},
      journal = {Chem. Phys.},
      year = {1987},
      volume = {112},
      pages = {245-251},
    }					
    Bíró, T., Diószeghy, T., Kelemen, A. & Lőrincz, A. Radiation dosimetry by photo-acoustic spectrometry 1986 Rad. Prot. Dos.   article
    BibTeX:
    @article{biro86radiation,
      author = {T. B{\'\i}r{\'o} and T. Di{\'o}szeghy and A. Kelemen and A. L{\H{o}}rincz},
      title = {Radiation dosimetry by photo-acoustic spectrometry},
      journal = {Rad. Prot. Dos.},
      year = {1986},
      volume = {17},
      pages = {259-262},
    }					
    Diószeghy, T., Miklós, A., Kelemen, A. & Lőrincz, A. Uncoupled Helmholtz resonator: An open photoacoustic cell 1985 J. Appl. Phys.   article
    BibTeX:
    @article{dioszeghy85uncoupled,
      author = {T. Di{\'o}szeghy and A. Mikl{\'o}s and A. Kelemen and A. L{\H{o}}rincz},
      title = {Uncoupled {Helmholtz} resonator: An open photoacoustic cell},
      journal = {J. Appl. Phys.},
      year = {1985},
      volume = {59},
      pages = {2105-2108},
    }					
    Lőrincz, A., Smith, D. D., Novak, F., Kosloff, R., Tannor, D. J. & Rice, S. A. Rotational state dependence of pyrazine fluorescence: Initial decays for the vibrationless  B13u state 1985 J. Chem. Phys.   article
    BibTeX:
    @article{lorincz85rotational,
      author = {A. L{\H{o}}rincz and D. D. Smith and F. Novak and R. Kosloff and D. J. Tannor and S. A. Rice},
      title = {Rotational state dependence of pyrazine fluorescence: Initial decays for the vibrationless {$B^1_{3u}$} state},
      journal = {J. Chem. Phys.},
      year = {1985},
      volume = {82},
      pages = {1067-1072},
    }					
    Novak, F., Kosloff, R., Tannor, D. J., Lőrincz, A., Smith, D. D. & Rice, S. A. Wave packet evolution in isolated pyrazine molecules: Coherence triumphs over chaos 1985 J. Chem Phys.   article
    BibTeX:
    @article{novak85wave,
      author = {F. Novak and R. Kosloff and D. J. Tannor and A. L{\H{o}}rincz and D. D. Smith and S. A. Rice},
      title = {Wave packet evolution in isolated pyrazine molecules: Coherence triumphs over chaos},
      journal = {J. Chem Phys.},
      year = {1985},
      volume = {82},
      pages = {1073-1078},
    }					
    Andor, L., Lőrincz, A., Siemion, J., Smith, D. D. & Rice, S. A. Shot-noise-limited detection scheme for two-beam laser spectroscopies 1984 Rev. Sci. Instrum   article
    BibTeX:
    @article{andor84shotnoise,
      author = {L. Andor and A. L{\H{o}}rincz and J. Siemion and D. D. Smith and S. A. Rice},
      title = {Shot-noise-limited detection scheme for two-beam laser spectroscopies},
      journal = {Rev. Sci. Instrum},
      year = {1984},
      volume = {55},
      pages = {64-67},
    }					
    Lőrincz, A., Novak, F. A. & Rice, S. A. Instantaneous relaxation following ultrafast excitation 1984 Ultrafast phenomena 4   inproceedings
    BibTeX:
    @inproceedings{lorincz84instantaneous,
      author = {A. L{\H{o}}rincz and F. A. Novak and S. A. Rice},
      title = {Instantaneous relaxation following ultrafast excitation},
      booktitle = {Ultrafast phenomena 4},
      year = {1984},
      editor = {D. A. Auston and K. B. Eisenthal},
      volume = {38},
      series = {Springer Ser. in Chem. Phys.},
      pages = {387-389},
      address = {Berlin, Heidelberg},
      publisher = {Springer},
    }					
    Lőrincz, A., Novak, F. A., Smith, D. D. & Rice, S. A. The pyrazine mystery: A resolution 1984 Ultrafast phenomena 4   inproceedings
    BibTeX:
    @inproceedings{lorincz84pyrazine,
      author = {A. L{\H{o}}rincz and F. A. Novak and D. D. Smith and S. A. Rice},
      title = {The pyrazine mystery: A resolution},
      booktitle = {Ultrafast phenomena 4},
      year = {1984},
      editor = {D. A. Auston and K. B. Eisenthal},
      volume = {38},
      series = {Springer Ser. in Chem. Phys.},
      pages = {362-365},
      address = {Berlin, Heidelberg},
      publisher = {Springer},
    }					
    Lőrincz, A., Novak, F. A. & Rice, S. A. Relaxation of large molecules following ultrafast excitation 1984 Chem. Phys. Lett.   article
    BibTeX:
    @article{lorincz84relaxation,
      author = {A. L{\H{o}}rincz and F. A. Novak and S. A. Rice},
      title = {Relaxation of large molecules following ultrafast excitation},
      journal = {Chem. Phys. Lett.},
      year = {1984},
      volume = {111},
      pages = {322-325},
    }					
    Smith, D. D., Lőrincz, A., Siemion, J. & Rice, S. A. Comment on vibrational energy redistribution in the isolated dimethyltetrazine dimer 1984 J. Chem. Phys.   article
    BibTeX:
    @article{smith84comment,
      author = {D. D. Smith and A. L{\H{o}}rincz and J. Siemion and S. A. Rice},
      title = {Comment on vibrational energy redistribution in the isolated dimethyltetrazine dimer},
      journal = {J. Chem. Phys.},
      year = {1984},
      volume = {81},
      pages = {2295-2296},
    }					
    Lőrincz, A. & Beleznay, F. Infrared divergence and the Scher-Montroll model for transient electrical transport in amorphous semiconductors 1982 Solid State Communications   article
    BibTeX:
    @article{lorincz82infrared,
      author = {A. L{\H{o}}rincz and F. Beleznay},
      title = {Infrared divergence and the {Scher-Montroll} model for transient electrical transport in amorphous semiconductors},
      journal = {Solid State Communications},
      year = {1982},
      volume = {44},
      pages = {109-111},
    }					
    Lőrincz, A., Puma, M., James, F. J. & Crawford, Jr, J. H. Thermally stimulated processes involving defects in gamma- and x-irradiated spinel ( MgAl2O4) 1982 J. Appl. Phys.   article
    BibTeX:
    @article{lorincz82thermally,
      author = {A. L{\H{o}}rincz and M. Puma and F. J. James and Crawford, Jr, J. H.},
      title = {Thermally stimulated processes involving defects in gamma- and x-irradiated spinel {($MgAl_2O_4$)}},
      journal = {J. Appl. Phys.},
      year = {1982},
      volume = {53},
      pages = {927-937},
    }					
    Puma, M., Lőrincz, A., Andrews, J. F. & Crawford, Jr, J. H. Dielectric behavior of  MgO:LiF+ crystals 1982 J. Appl. Phys.   article
    BibTeX:
    @article{puma82dielectric,
      author = {M. Puma and A. L{\H{o}}rincz and J. F. Andrews and Crawford, Jr, J. H.},
      title = {Dielectric behavior of {$MgO:LiF^{+}$} crystals},
      journal = {J. Appl. Phys.},
      year = {1982},
      volume = {53},
      pages = {4546-4548},
    }					
    Benkő, L., Bíró, T., Lőrincz, A. & Pátkai, G. Applications of solid state dosimetry: Thermoluminescent dating and thermocurrent dosimetry 1980 Izotópalkalmazási Kutatások, Institute of Isotopes   article
    BibTeX:
    @article{benko80applications,
      author = {L. Benk{\H{o}} and T. B{\'\i}r{\'o} and A. L{\H{o}}rincz and G. P{\'a}tkai},
      title = {Applications of solid state dosimetry: Thermoluminescent dating and thermocurrent dosimetry},
      journal = {Izot{\'o}palkalmaz{\'a}si Kutat{\'a}sok, Institute of Isotopes},
      year = {1980},
      pages = {165-186},
    }					
    Lőrincz, A. Correct results via thermally stimulated current measurements in bulk materials 1980 Physica Status Solidi A   article
    BibTeX:
    @article{lorincz80correct,
      author = {A. L{\H{o}}rincz},
      title = {Correct results via thermally stimulated current measurements in bulk materials},
      journal = {Physica Status Solidi A},
      year = {1980},
      volume = {61},
      pages = {K91-K94},
    }					
    Lőrincz, A., Benkő, L., Bíró, T. & Pátkai, G. Dosimetrical method using thermocurrents 1977 Proceedings of the International Conference on Personal Dosimetry   inproceedings
    BibTeX:
    @inproceedings{lorincz77dosimetrical,
      author = {A. L{\H{o}}rincz and L. Benk{\H{o}} and T. B{\'\i}r{\'o} and G. P{\'a}tkai},
      title = {Dosimetrical method using thermocurrents},
      booktitle = {Proceedings of the International Conference on Personal Dosimetry},
      year = {1977},
      pages = {336-339},
      address = {Hradec Kralove, Czechoslovakia},
      month = {May},
    }					

    Note: For the correct abbreviation of certain Hungarian names (e.g., Zsolt -> Zs. and not Z.) using BibTeX, special commands can be found in some .bib files (\Zs, \Gy, \Sz, \Cs). For such entries, paste the following to the beginning of your .bib file: @preamble{"\newcommand{\Zs}{Zs} \newcommand{\Gy}{Gy} \newcommand{\Sz}{Sz} \newcommand{\Cs}{Cs}"}.