neuron-request@HPLABS.HP.COM ("Neuron-Digest Moderator Peter Marvit") (04/10/90)
Neuron Digest Monday, 9 Apr 1990 Volume 6 : Issue 24 Today's Topics: re: sensory input vs. memory Neural Net Chips? New Book announced PSYCOLOQUY: 2 Positions Available (97 lines) Call for Papers CALL FOR PAPERS TR announcements Technical Report available Post-Doc position available Send submissions, questions, address maintenance and requests for old issues to "neuron-request@hplabs.hp.com" or "{any backbone,uunet}!hplabs!neuron-request" Use "ftp" to get old issues from hplpm.hpl.hp.com (15.255.176.205). ------------------------------------------------------------ Subject: re: sensory input vs. memory From: ashley@cheops.eecs.unsw.oz.au (Ashley Aitken) Date: Mon, 02 Apr 90 12:14:07 -0500 Stephen Smoliar asks "... can a phenotype born without any sensory input possibly have any memory?" As always there are many ways to interpret what one means by terms such as "memories". Surely, if you have no sensory input (and you haven't initialized the system from a previously sensory capable system, as others have suggested) then there can be no memories of sensory or external events ie. there can be no sensory memories. However, when one considers how reflexive the brain is and, in particular, the fact that well over 90% of inputs to the cortex are from the cortex itself [Braitenberg V., any of his articles or books, almost], one is tempted to think that the process would continue and form memories (categorize, and do all the other neat things the brain does) with internal events (and by this I do not mean visceral inputs). Perhaps in the same way we can remember "when we thought about ...." Clearly, there would be no understanding (via memory) of motor events because the brain would be completely oblivious to them (ie. they would not exist!) as an external actions. Lastly, I should just add that I find it very difficult to comprehend this world of internal sensation and how they could have any *useful* memories. However, I can also understand why one with sensory input would find it difficult to understand one without, in a similar way to how we have trouble understanding bats picture of the world. Regards, Ashley Aitken. E-MAIL ashley%cheops.eecs.unsw.oz@uunet.uu.net ARPAnet ashley@cheops.eecs.unsw.oz.au ARPAnet POSTAL School of Electrical Engineering and Computer Science, University of New South Wales, AUSTRALIA. [ "Without sensation and the ability to process sensation, there can be no memory." I assume here that "the ability to process sensation" refers to somewhat early processing of sensory input. The other extreme would seem to imply that even the memory process itself is processing sensation, and clearly without that there can be no memories. ] ------------------------------ Subject: Neural Net Chips? From: shriver@usl.edu (Shriver Bruce D) Date: Sat, 07 Apr 90 07:51:19 -0500 Please recommend other bulletin boards that you think are also appropriate. =============================================================== I am interested in learning what experiences people have had using neural network chips. In an article that Colin Johnson did for PC AI's January/February 1990 issue, he listed the information given below about a number of NN chips (I've rearranged it in alphabetical order by company name). This list is undoubtedly incomplete (no efforts at universities and industrial research laboratories are listed, for example) and may have inaccuracies in it. Such a list would be more useful if it would contain the name, address, phone number, FAX number, and electronic mail address of a contact person at each company would be identified. Information about the hardware and software support (interface and coprocessor boards, prototype development kits, simulators, development software, etc.) is missing. Additionally, pointers to researchers who are planning to or have actually been using these or similar chips would be extremely useful. I am interested in finding out the range of intended applications. Could you please send me: a) updates and corrections to the list b) company contact information c) hardware and software support information d) information about plans to use or experiences with having used any of these chips (or chips that are not listed) In a few weeks, if I get a sufficient response, I will resubmit an enhanced listing of this information to the bulletin boards to which I originally sent this note. Thanks, Bruce Shriver (shriver@usl.edu) ================================================================= Company: Accotech Chip Name: AK107 Description: an Intel 8051 digital microprocessor with its on- chip ROM coded for neural networks Availability: available now Company: Fujitsu Ltd. Chip Name: MB4442 Description: one neuron chip capable of 70,000 connections per second Availability: available in Japan now Company: Hitachi Ltd. Chip Name: none yet Description: information encoded in pulse trains Availability: experimental Company: HNC Inc. Chip Name: HNC-100X Description: 100 million connections per second Availability: Army battlefield computer Company: HNC Chip Name: HNC-200X Description: 2.5 billion connections per second Availability: Defense Advanced Research Projects Agency (DARPA) contract Company: Intel Corp Chip Name: N64 Description: 2.5 connections per second 64-by-64-by-64 with 10,000 synapses Availability: available now Company: Micro Devices Chip Name: MD1210 Description: fuzzy logic combined with neural networks in its fuzzy comparator chip Availability: available now Company: Motorola Inc. Chip Name: none yet Description: "whole brain" chip models senses, reflex, instinct- the "old brain" Availability: late in 1990 Company: NASA, Jet Propulsion Laboratory (JPL) Chip Name: none yet Description: synapse is charge on capacitors that are refreshed from RAM Availability: experimental Company: NEC Corp. Chip Name: uPD7281 Description: a data-flow chip set that NEC sells on PC board with neural software Availability: available in Japan Company: Nestor Inc. Chip Name: NNC Description: 150 million connections per second, 150,000 connections Availability: Defense Dept. contract due in 1991 Company: Nippon Telephone and Telegraph (NTT) Chip Name: none yet Description: massive array of 65,536 one-bit processors on 1024 chips Availability: experimental Company: Science Applications International. Corp. Chip Name: none yet Description: information encoded in pulse trains Availability: Defense Advanced Research Projects Agency (DARPA) contract Company: Syntonic Systems Inc. Chip Name: Dendros-1 Dendros-2 Description: each has 22 synapses, two required by any number can be used Availability: available now ------------------------------ Subject: New Book announced From: Matthew Zeidenberg <zeiden@cs.wisc.edu> Date: Fri, 30 Mar 90 11:48:22 -0600 My book "Neural Networks in Artificial Intelligence" has recently been published by Ellis Horwood Ltd., Chichester UK. They are now a division of Simon and Schuster, who will be distributing the book in the U.S. The price is $39.95, and the ISBN is 0-13-612185-3. It is available from your bookseller, or direct from Simon and Schuster Mail Order Sales Dept., 200 Old Tappan Rd., Old Tappan NJ 07675. European ordering address: Ellis Horwood Ltd., Market Cross House, Cooper St., Chichester, West Sussex, PO19 1EB, England (Price in pounds: 24.95) The book is a relatively consise (268 pp.) introduction to network models, yet manages to cover most of the best-known network paradigms, and is applications-oriented, with a chapter devoted to each of several areas in AI. Matt Zeidenberg P.S. Here is the table of contents: Chapter 1 Issues in Neural Network Modeling 15 1.1. Introduction 15 1.2. The Statistical Nature of Connectionist Models 17 1.3. Relevance of the Brain 19 1.4. Distributed vs. Local Connectionism 20 1.5. Distributed Models: A Critique 26 1.6. Connectionist Models and the Fuzzy Propositional Approach 27 1.7. Philosophical Issues 29 1.8. Smolensky's "Proper Treatment" of Connectionism 29 1.9. Connectionism: A New Form of Associationism? 35 Chapter 2 Neural Network Methods for Learning and Relaxation 41 2.1. Introduction 41 2.2. Types of Model Neurons 46 2.3. Types of Activation Rules 48 2.4. Early Learning Models 49 2.5. Hebbian and Associative Learning 51 2.6. Kohonen's Work on Associative Learning 54 2.7. Willshaw's Binary Associator 56 2.8. Hopfield's Non-linear Auto-associator 56 2.9. Modeling Neurons with Differential Equations 60 2.10. Simulated Annealing in the Boltzmann Machine 62 2.11. Learning Weights in the Boltzmann Machine 64 2.12. Error Back-Propagation 67 2.13. Applications of Back-propagation 70 2.14. Learning Family Relationships 71 2.15. Competitive Learning 73 2.16. Competitive Learning using Feed-forward Networks 73 2.17. Competitive Learning using Adaptive Resonance Theory 78 2.18. Kohonen's Self-organizing Topological Maps 82 2.19. A Population Biology Approach to Connectionism 86 2.20. Genetic Algorithms 91 2.21. Reinforcement Algorithms 94 2.22. Temporal Difference Methods 98 2.23. Problem-Solving Using Reinforcement and Back-propagation 2.24. Problem-Solving Networks 107 2.25. Extensions to Learning Algorithms 111 2.26. Escaping From Local Minima 112 2.27. Creating Bottlenecks 113 2.28. Sequential Learning 115 2.29. Remembering Old Knowledge 117 2.30. Sequential Processing 120 2.31. Image Compression Using a Back-propagation Auto-associator 122 2.32. Representing Recursive Structures 123 Chapter 3 Production Systems and Expert Systems 127 3.1. Introduction 127 3.2. A Connectionist Production System 128 3.3. Saito and Nakano's Connectionist Expert System 131 3.4. Gallant's Connectionist Expert System 134 Chapter 4 Knowledge Representation 138 4.1. Introduction 138 4.2. Storing Schemata in Neural Networks 139 4.3. Storing Frames in Neural Networks 140 4.4. Storing Schemata with a Complex Neural Architecture 144 4.5. Learning Microfeatures for Knowledge Representation 148 4.6. Implementing Evidential Reasoning and Inheritance Hierarchies 151 Chapter 5 Speech Recognition and Synthesis 157 5.1. Introduction 157 5.2. Comparing Algorithms for Speech Recognition 158 5.3. Speech Recognition as Sequence Comparison 160 5.4. The Temporal Flow Model 163 5.5. The TRACE model 165 5.6. A Model of the Print-to-speech Transformation Process 168 5.7. NETtalk: Reading Aloud with a Three-Layer Perceptron 172 Chapter 6 Visual Perception and Pattern Recognition 177 6.1. Introduction 177 6.2. Interpreting Origami Figures 178 6.3. Recognition Cones 183 6.4. Separating Figure from Ground 185 6.5. Determining "What" and "Where" in a Visual Scene 188 6.6. Linking Visual and Verbal Semantics 192 6.7. Recognizing Image-schemas 193 Chapter 7 Language Understanding 195 7.1. Introduction 195 7.2. Processing Finite State Grammars Sequentially 200 7.3. Sentence Interpretation 205 7.4. Word Sense Disambiguation 210 7.5. Making Case Role Assignments 212 7.6. The MPNP Parsing System 215 7.7. Parsing Strings from Context-Free Grammars 218 7.8. PARSNIP: A Parsing System Based on Back-propagation 221 7.9. A Quasi-Context-Free Parsing System 223 7.10. Parsing Using a Boltzmann Machine 225 7.11. Learning the Past Tense 227 7.12. A Critique of "Learning the Past Tense" 230 7.13. Letter and Word Recognition 232 ------------------------------ Subject: PSYCOLOQUY: 2 Positions Available (97 lines) From: Stevan Harnad <harnad%Princeton.EDU@VM.TCS.Tulane.EDU> Date: Sun, 01 Apr 90 14:22:35 -0400 *** PSYCOLOQUY: Sponsored on an experimental basis by the Science Directorate of the American Psychological Association 202/955-7653 *** 1. Postdoctoral position in cognitive neuroscience -- San Diego 2. One-Year Position in Cognitive Psychology -- Haverford College ------------------------------------------------------------------------- 1. Subject: POSTDOCOTRAL POSITION IN COGNITIVE NEUROSCIENCE -- SAN DIEGO From: trejo@nprdc.navy.mil (Leonard J. Trejo) POSTDOCTORAL POSITION IN COGNITIVE NEUROSCIENCE -- SUMMER/FALL 1990 The Neurosciences Division of the Navy Personnel Research and Development Center (NPRDC), San Diego, is looking for a recent Ph. D. to study electrophysiological correlates of human cognition. Ongoing research includes neuroelectric (EEG and ERP) and neuromagnetic (evoked field) technology. The primary emphasis is on the improvement of on-job performance prediction and training; however, considerable emphasis is given to basic research issues. Another area of interest is in real-time electrophysiological signal processing using adaptive filters and neural networks. The well-equipped Neuroscience Labora- tory includes two Concurrent computer systems, several '386 PC sys- tems, a Macintosh SE, and other equipment, as well as extensive stimulus presentation, data acquisition and analysis software. Access privileges to VAX 11/780, IBM 4341, and SUN 4 systems, and the INTER- NET network are also available. An associate investigator role will be assumed by the successful candidate and he/she will be expected to develop a line of research in concert with Center goals. Qualifications include: 1. U. S. Citizenship 2. Ph. D., Sc. D., or equivalent in psychology or neuroscience received not more than 7 years from date of award Additional experience desired: 1. Cognitive psychophysiology training / experience 2. Experimental design / methodology 3. Multivariate / univariate statistics 4. Proficiency with UNIX and C programming The position is available through the Postdoctoral Fellowship Program funded by the U.S. Navy Office of Naval Technology (ONT) and administered by the American Society for Engineering Education (ASEE). Duration of the appointment is for one year, and may be renewed for up to two additional years. Stipends range from $34,000 to $38,000 per annum depending upon experience. A relocation allowance may be nego- tiated; the amount is based on the personal situation of the partici- pant. Funds will be available for limited professional travel. NPRDC is located on top of Pt. Loma, overlooking San Diego Harbor and downtown San Diego. Reasonably priced rental housing is available in within a 5-mile radius of the Center. San Diego offers an excel- lent climate and environment as well as a wide range of academic, mil- itary, and industrial research institutions. The application deadlines are April 1, 1990, for terms beginning in the summer, and July 1, 1990, for terms beginning in the fall. For information about the ONT Postdoctoral Fellowship Program and an application form, please contact: American Society for Engineering Education Projects Office, Attention: Bob Davis 11 Dupont Circle, Suite 200 Washington, DC 20036 (202) 293-7080 For information about the NPRDC Neurosciences Division, contact: Dr. Leonard J. Trejo Neuroscience Division, Code 141 Navy Personnel Research and Development Center San Diego, CA 92152-6800 (619) 553-7711 INTERNET: trejo@nprdc.navy.mil UUCP: ucsd!nprdc!trejo ---------------------------------------------------------------- 2. One-Year Position in Cognitive Psychology -- Haverford College From: D_DAVIS%hvrford.bitnet (Douglas Davis) Haverford College is seeking a one-year sabbatical leave replacement for the 1990-91 academic year in the area of cognitive psychology. An emphasis on ecological approaches would be especially appropriate. Candidates should be able to teach Introductory Cognitive Psychology, Experimental Design, Memory & Cognition, and an advanced course in some other area of cognition such as Psycholinguistics, as well as supervise senior thesis research. Haverford College is a small, highly selective liberal arts college in the Philadelphia suburbs. Salaries are competitive, and fringe benefits are excellent. Haverford College is an Equal Opportunity/Affirmative Action employer. Interested candidates should send a vita and 3 letters of reference to: Douglas Davis, Chair, Department of Psychology, Haverford College, Haverford PA l9041. (215) 896-1236 ------------------------------ Subject: Call for Papers From: Elan Moritz <71620.3203@CompuServe.COM> Date: 01 Apr 90 23:07:09 -0400 please post and distribute to investigators of: ========================== * human and machine intelligence * knowledge systems * computational linguistics * natural languages * theoretical biology * population genetics * ethology / cultural ecology * information storage and transfer * learning and teaching systems * philosophy of knowledge * philosophy and history of science ++++++++++++++++++++++++++++++++++++++++++++++++++ NEW JOURNAL ANNOUNCEMENT & CALL FOR PAPERS ...................... . . . JOURNAL of IDEAS . ...................... IMR, BOX 16327, PANAMA CITY, FLORIDA 32406, USA ++++++++++++++++++++++++++++++++++++++++++++++++++ The Institute for Memetic Research [IMR] is publishing a new journal called 'Journal of Ideas'. The main purpose of the journal is to provide an archival forum for discussion of the genesis, evolution, competition and death of 'ideas' and 'memes'. The term 'idea' is one that requires careful discussion. The original term 'meme' [pronounced: meem] is a conceptual construct introduced by Richard Dawkins to describe units of cultural transmission and imitation. IMR uses the term 'meme' as a point of departure for an area we call 'Memetic Science'. Ultimately, 'meme' requires further definition and clarification. The primary thesis of Memetic Science is that 'ideas' and 'memes' are entities that are functionally similar to biological genes in their ability to replicate, mutate, and undergo natural selection. What are sought in Memetic Science are: rigorous quantitative foundations, theory, and experimental methodology and measurements. The history of the study of 'ideas'-as-entities-by-themselves is ancient. As philosophers, we have a variety of qualitative theories and speculations. Logic theory, philology, modern linguistics, and computer oriented technologies, have provided a start in the area of understanding structures, grammars, and truth conditions of sentences and small collections of sentences. Population geneticists and biologists have provided initial models for spread of 'cultural' constructs. These models incorporate the techniques of dominant/recessive allele spreading in genetic pools and epidemiological approaches. Some models use compound constructs of 'gene + culture' elements as the particulate elements that replicate and propagate. While the contributions from these diverse disciplines are useful, there are needs for systematic, robust and, most importantly, quantitative approaches. Present day applications of Memetic Science include both human aspects of replication, mutation, competition, spread and death of ideas and memes, as well as their electronic analogs. The 'electronic memes' are beneficial messages, reusable subroutines, programs that are freely [or surreptitiously] copied and modified, computer viruses, worms, trojan horses, etc. To address the needs stated above the Institute for Memetic Research is launching the Journal of Ideas (first issue printing, September 1990). The detailed statement of scope, pivotal references, subscription information, and instruction for authors is available upon written request from: Elan Moritz, Editor Journal of Ideas The Institute for Memetic Research Box 16327 Panama City, Florida 32406, USA email address: INTERNET: 71620.3203@compuserve.com or INET: 71620.3203@compuserve.com The Journal of Ideas will appear [initially] quarterly, and will contain the following reqular sections: 1) Invited papers, 2) Research Contributions, 3) Rapid Publications and 4) Discussion of persistence and spread of existing 'Major Ideas'. Only previously unpublished papers will be accepted. Page charges for invited papers will be waived. Brevity, and jargon accessible to interdisciplinary researchers are encouraged. Standard transfer of copyrights is required prior to printing. To encourage participation and discussion of this new area, IMR/JoI will experiment with two categories of papers. One category will be strictly reviewed and refereed, while another will be reviewed by the editor but not refereed. Non-refereed papers will be so marked; they will have the advantages of rapid publication and possible disadvantages of archival of errors. To expedite processing, authors can immediately submit papers prepared according to a standard professional society [e.g. IEEE, AIP, APS] journal manuscript format. Three copies are required. On an experimental basis, authors who would like to submit papers for rapid publication using email may submit papers using the internet address [INTERNET: 71620.3203@compuserve.com]. These papers should consist of ASCII text only, with equations built up carefully using ASCII text. Papers submitted through email should be followed up by submitting a written version via regular postal channels. Readers of this message are encouraged to suggest topics and individuals [including themselves] to be considered for invited papers. ------------------------------ Subject: CALL FOR PAPERS From: "Centro de Inteligencia Artificial(ITESM)" <ISAI@TECMTYVM.MTY.ITESM.MX> Organization: Instituto Tecnologico y de Estudios Superiores de Monterrey Date: Wed, 04 Apr 90 12:11:38 -0600 [[ Editor's Note: Since this has been posted previously, I'm not including the lengthy list of program participants. -PM ]] Call for Papers Third International Symposium on Artificial Intelligence: Applications of Engineering Design, Manufacturing & Management in Industrialized and Developing Countries October 22-26, 1990 ITESM, MEXICO The Third International Symposium on Artificial Intelligence will be held in Monterrey, N.L. Mexico on October 22-26, 1990. The Symposium is sponsored by the ITESM (Instituto Tecnologico y de Estudios Superiores de Monterrey) in cooperation with the International Joint Conferences on Artificial Intelligence Inc., the American Association for Artificial Intelligence, the Sociedad Mexicana de Inteligencia Artificial and IBM of Mexico. Papers from all countries are sought that (1) present innovative applications of artificial intelligence technology to the solution of industrial problems in engineering design, manufacturing and management; (2) explore its relevance for developing countries; and (3) describe research on techniques to accomplish such applications. AREAS OF APPLICATION include but are not limited to: * Production planning,* resource management, * quality management, * automated assembly, * machine loads, * inventory control, * computer aided product design, *computer aided product manufacturing * human resources management, * forecasting, *client/customer support, * process control and ES, * automatic process inspection, * use of industrial robots, * market and competition analysis, * strategic planning of manufacturing, * technology management and social impact of AI technology in industrial environments. AI TECHNIQUES include but are not limited to: * Knowledge acquisition and representation, * natural language processing, * robotics , * speech recognition, * computer vision, * neural networks and genetic algorithms, * parallel architectures, * automatec learning, * automated reasoning, * search and problem solving, * knowledge engineering tools and methodologies, * uncertainty management and AI programming languages. Persons wishing to submit a paper should send five copies written in english to: HUGO TERASHIMA PROGRAM CHAIR CENTRO DE INTELIGENCIA ARTIFICIAL, ITESM SUCURSAL DE CORREOS "J", C.P. 64849 MONTERREY, N.L. MEXICO The paper should identify the area and technique to which it belongs. Extended abstract is not required.Use font similar to "times",size 12 single-spaced, with a maximum of 10 pages. No papers will be accepted by electronic means. IMPORTANT DATES: Papers must be received by April 30, 1990.Papers received after the deadline will be returned unopened. Authors will be notified by June 30, 1990. A final copy of each accepted paper, camera ready for inclusion in the Symposium proceedings will be due by July 30, 1990. INFORMATION.- CENTRO DE INTELIGENCIA ARTIFICIAL, ITESM. SUC. DE CORREOS "J", C.P. 64849 MONTERREY, N.L. MEXICO. TEL (52-83) 58-20-00 EXT.5134. TELEFAX (52-83) 58-07-71, (52-83) 58-89-31, NET ADDRESS: ISAI AT TECMTYVM.BITNET ISAI AT TECMTYVM.MTY.ITESM.MX GENERAL CHAIR: Francisco J. Cantu-Ortiz, ITESM, Mexico ------------------------------ Subject: TR announcements From: "Songnian Qian" <sqian%demos@lanl.gov> Date: Thu, 05 Apr 90 10:16:48 -0600 ANNOUNCEMENT Following techenical reports are avialable to public: 1) FUNCTION APPROXIMATION WITH AN ORTHOGONAL BASIS NET Abstract An orthogonal basis net (OrthoNet) is studied for function approximation. The network transfers input space to a new space in which the orthogonal basis function is easy to construct. This net has the advantages of fast and accurate learning, the ability to deal with high dimensional systems and has only one minimum so that local minima are not attractors for the learning algorithm. 2) Adaptive Stochastic Cellular Automata: Theory Abstract The mathematical concept of cellular automata has been generalized to allow for the possibility that the uniform local interaction rules that govern conventional cellular automata are replaced by nonuniform local interaction rules which are drawn from the same probability distribution function, in order to guarantee the statistical homogeneity of the cellular automata system. Adaptation and learning in such a system can be accomplished by evolving the probability distribution function along the steepest descent direction of some objective function in a statistically unbiased way to ensure that the cellular automata's dynamical behavior approaches the desired behavior asymptotically. The proposed CA model has been shown mathematically to possess the requisite convergence property under general conditions. 3) Adaptive Stochastic Cellular Automata: Applications Abstract The stochastic learning cellular automata model has been applied to the problem of controlling unstable systems. Two example unstable systems are controlled by an adaptive stochastic cellular automata algorithm with an adaptive critic. The reinforcement learning algorithm and the architecture of the stochastic CA controller are presented. Learning to balance a single pole is discussed in detail. Balancing an inverted double pendulum highlights the power of the stochastic CA approach. The stochastic CA model is compared to conventional adaptive control and artificial neural network approaches. Please email your requist to sqian@merlin.lanl.gov or mail your requist to Songnian Qian Center for Nonlinear Studies Mail Stop B-258 Los Alamos National Laboratory Los Alamos, New Mexico 87545 ------------------------------ Subject: Technical Report available From: Melanie Mitchell <mm@cogsci.indiana.edu> Date: Fri, 06 Apr 90 16:28:52 -0500 The following technical report is available from the Center for Research on Concepts and Cognition at Indiana University: The Right Concept at the Right Time: How Concepts Emerge as Relevant in Response to Context-Dependent Pressures (CRCC Report 42) Melanie Mitchell and Douglas R. Hofstadter Center for Research on Concepts and Cognition Indiana University Abstract A central question about cognition is how, when faced with a situation, one explores possible ways of understanding and responding to it. In particular, how do concepts initially considered to be irrelevant, or not even considered at all, become relevant in response to pressures evoked by the understanding process itself? We describe a model of concepts and high-level perception in which concepts consist of a central region surrounded by a dynamic nondeterministic "halo" of potential associations, in which relevance and degree of association change as processing proceeds. As the representation of a situation is constructed, associations arise and are considered in a probabilistic fashion according to a "parallel terraced scan", in which many routes toward understanding the situation are tested in parallel, each at a rate and to a depth reflecting ongoing evaluations of its promise. We describe Copycat, a computer program that implements this model in the context of analogy-making, and illustrate how the program's ability to flexibly bring in appropriate concepts for a given situation emerges from the mechanisms that we are proposing. (This paper has been submitted to the 1990 Cognitive Science Society conference.) To request copies of this report, send mail to mm@cogsci.indiana.edu or mm@iuvax.cs.indiana.edu or Melanie Mitchell Center For Research on Concepts and Cognition Indiana University 510 N. Fess Street Bloomington, Indiana 47408 ------------------------------ Subject: Post-Doc position available From: Dan Kersten <kersten@eye.psych.UMN.EDU> Date: Mon, 09 Apr 90 10:08:48 -0500 UNIVERSITY OF MINNESOTA POST-DOCTORAL RESEARCH POSITIONS Two research positions available to study the linkages between the initial stages of human perception and later recognition. The research uses psychophysical and computational methods to understand these problems. Applicants must have a Ph.D. Background in computer modeling, psychoacoustics, visual psychophysics, perception, or supercomputers is highly desirable. Applicants capable of forging links between audition and vision will be given consideration. The research will be conducted at the Center for the Analyses of Perceptual Representations (CAPER) at the University of Minnesota . This Center encompasses four vision laboratories and one hearing laboratory in the Psychology and Computer Science departments, and includes ample facilities for simulation and experimental studies. Center faculty members are: Irving Biederman, Gordon Legge, Neal Viemeister, William Thompson, and Daniel Kersten. Salary level: $26,000 to $32,000 depending on the candidate's qualifications and experience. Appointment is a 100% time, 12-month appointment as post-doctoral fellow. (Appointment may be renewable, contingent on satisfactory performance and AFOSR funding.) Starting date is July 1, 1990 or as soon as possible. Candidates should submit a vita, three letters of reference, representative reprints and preprints, and a statement of long-term research interests to: Professor Irving Biederman, Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, Minnesota, 55455. Applications must be received by June 15, 1990. The University of Minnesota is an equal opportunity educator and employer and specifically invites and encourages applications from women and minorities. ------------------------------ End of Neuron Digest [Volume 6 Issue 24] ****************************************