From tkelley at arl.army.mil Thu Oct 6 11:47:40 2005 From: tkelley at arl.army.mil (Kelley, Troy (Civ,ARL/HRED)) Date: Thu, 6 Oct 2005 11:47:40 -0400 Subject: [ACT-R-users] ACT-R/Soar on a robot Message-ID: Hello, Since there is not a lot of activity on the ACT-R or Soar mailing list of late, I thought I would pose some theoretical questions to the community concerning work we have been doing at our lab to implement ACT-R onto a robot. We are working with a production system architecture called SS-RICS, which was inspired by ACT-R, and has much of the same functionality as ACT-R. Each paragraph below is meant to be a self-contained set of questions to ponder, if you want to respond to just one paragraph, please feel free to do so, you don't need to read all the paragraphs. Your input would be appreciated. 1) ACT-R grew out of the General Problem Solver (GPS) production system architecture developed by Newell and Simon. Their intent was to develop a *general* problem solver using various syntax based strategies. These are also known as weak method problem solvers in AI. However, it seems as if ACT-R has moved toward strong method problem solvers, which use *specific* domain knowledge to solve problems. So the question is, can we develop ACT-R/Soar models that are general adaptable problem solvers that are NOT domain specific? Or does domain specificity so influence the problem solving process, that one cannot extricate oneself from the domain? 2) ACT-R is firmly rooted in the "symbolic" side of AI as opposed to the "distributed" side of AI. A criticism of traditional symbolic AI is that it tends to be brittle and non-adaptive if the symbols do not match the current problem space. Is this also true of ACT-R? If so, does ACT-R seem to be a logical fit for robotics or will it just introduce the same set of symbolic problems (especially the frame problem) that are currently found in AI. 3) If one considers ACT-R to be "just another symbolic system", as some in the AI community do, then what does ACT-R or computational cognitive psychology have to offer the robotics community? I have not seen references to memory decay in the AI literature however, most people in the AI community consider memory decay to be a handicap of the human cognitive system. While I disagree with that, what other mechanisms/functionality of the human cognitive system would appear to be the most important additions to robotic control mechanism that have been overlooked by the AI community? 4) There is a distinction in psychological literature between long term, short term and working memory, but what does that mean computationally? For us, we have implemented different decay rates for LTM and STM. However, those decay rates are really part of a continuum of decay rates for all memories. For example, if we have one million memories on our robot, don't those memories form a continuum of various decay rates? Why should I have to have a place holder for LTM and STM and WM? Why can't all my memories just have various decay rates? It seems as if LTM, STM and WM are simply convenient labels for something that is really a continuum. If we define WM as those memories currently in use, does that preclude LTM or STM from the problem space? 4) Has there ever been any use of *different* decay rates *within* an ACT-R model? I am talking about different base level activations for different chunks at the beginning of the model run. For example, we have found it very helpful to code perceptual processing as building on lower level memories that decay very quickly. Once the higher level concepts are formed, the lower level memories are quickly forgotten, and the higher level concepts remain. So, the higher level concepts have a slower decay rate than the lower level perceptions. I know right now, in ACT-R, we request information from the buffers, but I have been working on some memory research that says that information will "get in" even if there is not a "request" for it (or an attentional shift to it). Perhaps this is more of a statement than a question then; what do people think of having more control over decay rates for individual chunks, especially those coming in from the perceptual components? 5) The transition from a rule-based, symbolic understanding of a problem, to a proceduralized, intuitive, understanding of a problem is difficult to represent computationally. What does proceduralization really mean? At the symbolic level, we can change latency values, or skip over rules, to speed up the procedure. But really, psychologically, it seems as if the symbolic level rules are being "rewritten" or "re-compiled" as subsymbolic representations. On our robot, it is unclear how we could take symbolic production systems and recompile them in a subsymbolic way to produce improved performance seen in humans. 6) When does a memory become and memory? When you first perceive something, is it a memory then or does it become a memory later? Is our conceptualization of the world a conceptualization of memories or actual stimuli? Does some level of processing have to take place before it can be called a memory? For example, with our robot, it sees dots and points returned from its laser, which are organized into lines. But we struggle with the idea that the dots and points are also memories. We have buffers similar to ACT-R, but we ended up having a lot of processing that goes on before information even gets to the buffer. So that means there is a lot of information unavailable to the production system. For example, points get organized into lines which then get organized into shapes at a Gestalt layer, which then become memories for the production system. So, a lot of processing goes on before our sensory data becomes a memory. So, again, when does a memory become a memory? 7) Is cognition sensory specific? Much of our code right now for the robot seems to be for interpreting information the robot gets from each one of its sensors. So, if we were to put a new sensor on the robot, would it still be able to make sense of the world? That is a direction we are going toward, but it can be very difficult. Many of the productions we end up writing seem to be tied directly to specific sensory stimuli, and it is difficult to write productions that are general and not tied to sensory information. So, is cognition bound to the sensory information returned from perceptual mechanisms (as Rodney Brooks would say) or can it be separated from sensory information. True, that is what the symbolic level can do, but then, does the symbolic level become brittle if it is not tied to the sensory layer? Troy Kelley U.S. Army Research Laboratory Human Research and Engineering Directorate AMSRD-ARL-HR-SE, APG, MD 21005-5425 Voice: 410-278-5859 email: tkelley at arl.army.mil -------------- next part -------------- An HTML attachment was scrubbed... URL: From Glenn.Gunzelmann at mesa.afmc.af.mil Thu Oct 6 12:13:52 2005 From: Glenn.Gunzelmann at mesa.afmc.af.mil (Glenn.Gunzelmann at mesa.afmc.af.mil) Date: Thu, 6 Oct 2005 09:13:52 -0700 Subject: [ACT-R-users] CogSci 2006 - Call For Symposia Message-ID: <671474002216D14B8D440C71877F9A8D01F68415@fsqbge07.williams.afmc.ds.amfc.af.mil> Apologies for multiple copies... CogSci 2006 The Twenty-Eighth Annual Conference of the Cognitive Science Society July 27-30, 2006 Tutorials/workshops day: July 26 [in cooperation with the 5th International Conference on Cognitive Science (Asia-Pacific)] Sheraton Vancouver Wall Centre Vancouver, Canada http://www.cogsci.rpi.edu/~rsun/cogsci2006/ We invite submissions for Symposia to the Twenty-Eighth Annual Conference of the Cognitive Science Society, the premier series of conferences in cognitive science. Proposals should consist of a 1-page summary of the topic (to be included in the Proceedings later on if accepted). Each proposal should identify the speakers and moderator and present detailed justifications, including the qualifications of the moderator and the speakers. All submissions should conform to the instructions, which appear at: http://www.cogsci.rpi.edu/~rsun/cogsci2006/submissions.html Deadline for submissions: 1 February, 2006 Submissions will be reviewed by an international panel of experts according to the following criteria: Significance; Relevance to a Broad Audience of Cognitive Science Researchers; Originality; Technical Merit; and Clarity of Presentation. Accepted symposia will be presented as 90-minute sessions at the Conference. Conference General Chairs: -Ron Sun (Rensselaer Polytechnic Institute) -Naomi Miyake (Chukyo University) Symposia Chair: -Glenn Gunzelmann (Air Force Research Laboratory) Important Dates: Paper/Symposium Submissions due: February 1, 2006 Acceptance notifications: April 15, 2006 Camera-ready copies due: May 15, 2006 _________________________________ Glenn Gunzelmann, Ph.D. Research Psychologist Air Force Research Laboratory Mesa, AZ _________________________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: From cassin at rpi.edu Thu Oct 6 13:07:52 2005 From: cassin at rpi.edu (Nick Cassimatis) Date: Thu, 6 Oct 2005 13:07:52 -0400 Subject: [ACT-R-users] RE: [soar-group] ACT-R/Soar on a robot In-Reply-To: Message-ID: <002101c5ca98$81ad38a0$bce57180@MACHINE> Troy, Many of your specific examples involve decay. Many AI people see memory decay as something you would NOT want to give a system, but it has at least one useful function that I have found in my modeling of infant physical reasoning. It keeps less-relevant memories and knowledge from impeding on your current thought. For example, while tracking an object move from point A to B, you perceive and form memories of intermediate motion events from A to p1, p1 to p2, p3 to p4, .... pn to B. For many tasks, those memories of intermediate motion events are irrelevant and having them inhibited helps. So, in AI terminology, decay can behave as a useful heuristic. The reason to not completely eliminate the memories of intermediate events (from a normative AI perspective) is that new information can make the relevant so you do not want to discard them. > skip over rules, to speed up the procedure.? But really, > psychologically, it seems as if the symbolic level rules are being >?rewritten? or ?re-compiled? as subsymbolic representations.? On our Maybe it just seems like this because the increase in speed makes them less accessible to what self-reflection, what ever that is. So introspective difference might not be accounted for by a qualitiive change in the rule matching, but instead by the limits of introspection. ? > 7) Is cognition sensory specific?? Much of our code right now for You can structure a system so its productions match against buffers that represent "mental images" that are to some degree isomorphic to your actual sensor input. So, on the one hand you have the supposed flexibility that comes form reacting to new stimuli, but on the other hand you have the added flexibility and power of reacting to/thinking about occluded, past and future parts of the world. Finally, many of your questions initially sounded dangerously vague and philosophical to me, "when is a memory a memory?", but you made sense of what you meant by referring to specific design features of models. I think avoiding potential confusions and pointless debates such as this could have been is itself a good reason for doing cognitive modeling. Best, -Nick From grayw at rpi.edu Tue Oct 18 10:35:39 2005 From: grayw at rpi.edu (Wayne Gray) Date: Tue, 18 Oct 2005 10:35:39 -0400 Subject: [ACT-R-users] Position at RPI Message-ID: Tenure-track Position in Cognitive Science The Cognitive Science Department at Rensselaer Polytechnic Institute invites applications for an anticipated tenure-track position at the rank of Assistant Professor beginning in Fall 2006 or possibly (for the right candidate) Spring 2007. We are seeking candidates who combine computational, mathematical, and/or logic-based modeling informed by experimental research in the areas of perception and action (e.g., motor control, vision, attention), interactive behavior (e.g., integrated models of cognitive systems), or high-level cognition (e.g., skill acquisition, decision making, reasoning). The candidate's interest can be in basic and/or applied theory-based research. Interests in areas such as robotics or high-level computational neuroscience will be considered a strength. However, all disciplines within cognitive science are potential sources of candidates. All candidates are expected to have a strong potential for external funding. The Cognitive Science Department at Rensselaer is among the world's newest dedicated cognitive science departments, specializing in computational cognitive modeling, perception/action, learning and reasoning (human and machine), and cognitive engineering. The department's primary mission is to carry out seminal basic research and to develop engineering applications within cognitive science. This effort requires the continued growth of its new, research-oriented doctoral program in cognitive science. Department faculty have excellent ties with faculty in Computer Science, Engineering, and Decision Sciences. Women and minorities are especially encouraged to apply. Send curriculum vitae, reprints and preprints of publications, a 1-to-2 page statement of research, a 1-page statement of teaching interests, and three letters of reference to: Search Committee, c/o Heather Hewitt, Cognitive Science Department, Carnegie Building, Rensselaer Polytechnic Institute,110 8th Street, Troy, NY 12180. (Direct queries via email to Prof. Wayne D. Gray, grayw at rpi.edu, Chair of the Search Committee.) Applications will be reviewed beginning December 1st and continuing until the position is filled. -- **Rensselaer**Rensselaer**Rensselaer**Rensselaer**Rensselaer** Wayne D. Gray; Professor of Cognitive Science Rensselaer Polytechnic Institute Carnegie Building (rm 108) ;;for all surface mail & deliveries 110 8th St.; Troy, NY 12180 EMAIL: grayw at rpi.edu, Office: 518-276-3315, Fax: 518-276-3017 for general information see: http://www.rpi.edu/~grayw/ for On-Line publications see: http://www.rpi.edu/~grayw/pubs/downloadable_pubs.htm for the CogWorks Lab see: http://www.cogsci.rpi.edu/cogworks/ If you just have formalisms or a model you are doing "operations research" or" AI", if you just have data and a good study you are doing "experimental psychology", and if you just have ideas you are doing "philosophy" -- it takes all three to do cognitive science. **Rensselaer**Rensselaer**Rensselaer**Rensselaer**Rensselaer** From eaboelela at umassd.edu Tue Oct 18 11:28:54 2005 From: eaboelela at umassd.edu (Dr. Emad Aboelela) Date: Tue, 18 Oct 2005 11:28:54 -0400 Subject: [ACT-R-users] CFP - eSCo-Wi (Due: November 29, 2005) Message-ID: <003d01c5d3f8$b587e760$640d5886@FILPeaboelela> (Please accept our apologies if you receive multiple copies of this CFP) =========================================================== C A L L F O R P A P E R S ----------------------------------------------------------------------------------------------------- First International Workshop on eSafety and Convergence of Heterogeneous Wireless Networks (eSCo-Wi) Phoenix, Arizona, U.S.A. April 10-12, 2006 In conjunction with 25th IEEE International Performance, Computing, and Communications Conference ============================================================ http://www.cis.umassd.edu/escowi/ Email: escowi at umassd.edu Paper Submissions ================= Submitted papers must represent original material that is not currently under review in any other conference or journal, and has not been previously published. Paper length should not exceed 6 pages technical paper manuscript. Submissions should include a cover page with authors' names, affiliations, fax and telephone numbers and e-mail addresses. All accepted papers will be published in the conference proceedings. At least one author of accepted papers is required to present the paper and to register at the full registration rate. Go to (www.edas.info/home.cgi?c=4657) to submit your manuscript via Editor's Assistant. Important Dates: -------------------- Paper submission due: November 29, 2005 Author notification due: January 10, 2006 Final paper submission due: February 7, 2006 Topics of Interest ================== With the realization of wide range of heterogeneous wireless networks from wireless local area networks (WLANs), second and third generations (2G/3G) of cellular networks to mobile ad hoc (MANET) and wireless sensor networks (WSN), many new applications such as Wireless Internet, Intelligent Transportation and Telemedicine are becoming realities. The fourth generation (4G) of wireless communications is expected to support such applications and to enable ubiquitous access to multimedia information and remote computing services regardless of location or mobility while integrating these different wireless technologies. In this Workshop we are especially interested to real time applications close to the security (road security, telemedicine, the fight of fires.). Network convergence through the co-existence and the interoperability between heterogeneous wireless networks, is therefore regarded as the major challenge in the integration of systems used in transportations, medical and other applications, to achieve safer mobility and wireless monitoring. In this context, the QoS constraints are considerable. The objective of this workshop is therefore to provide an eSafety forum for researchers and technologists. It aims to bring them together to discuss and exchange experimental or theoretical results, novel designs, work-in-progress, experience, case studies, and to present their contributions as technical papers related to the convergence of heterogeneous wireless networks towards real time safety applications through the intelligent control of mobile systems. We invite researchers and practitioners to submit theoretical and experimental results on topics of interest included but not limited to the following: * Physical layer issues for the convergence of heterogeneous wireless technologies * Efficient mobility and handoff management protocols for seamless roaming within the converged communication architecture * Resource management and allocation * Power control management * Admission, load and flow control * Performance analysis and experimentation of heterogeneous wireless networks * Security techniques and methods for heterogeneous wireless networks * Energy efficient medium access control, error control, and traffic management protocols * QoS in Heterogeneous Wireless Networks * Security, authentication, and billing solutions for the converged architecture * Interoperability among WLANs, Cellular, WSN and wired networks * Novel and adaptive communication protocols at all layers, i.e., MAC layer problems, routing, reliable and multimedia transport, for integration of diverse wireless systems * Simulation study of heterogeneous wireless networks * eSafety applications and measurements (Telemedicine solutions to healthcare problems, intelligent vehicles and driver assistance systems.) in Heterogeneous wireless networks. Workshop Co-Chairs ================== Tarek BEJAOUI (Paris XI University, IEF, France) tarek.bejaoui at ief.u-psud.fr Emad Aboelela (University of Massachusetts of Dartmouth, USA) eaboelela at umassd.edu Workshop Vice-Chair =================== Nidal Nasser (University of Guelph, Canada) nasser at cis.uoguelph.ca -------------- next part -------------- An HTML attachment was scrubbed... URL: From rsun at rpi.edu Thu Oct 20 16:20:25 2005 From: rsun at rpi.edu (Professor Ron Sun) Date: Thu, 20 Oct 2005 16:20:25 -0400 Subject: [ACT-R-users] Cognitive Systems Research, Vol. 6, Iss. 3 and 4, 2005 Message-ID: <1BA809C5-BE7C-4B7B-98F4-94FFFC12B8CA@rpi.edu> New Issues are now available on ScienceDirect: NOTE: If the URLs in this email are not active hyperlinks, copy and paste the URL into the address/location box in your browser. ----------------------------------------------------------------------- * Cognitive Systems Research Volume 6, Issue 3, Pages 189-262 (September 2005) Epigenetic Robotics Edited by Luc Berthouze and Giorgio Metta http://www.sciencedirect.com/science/issue/ 6595-2005-999939996-596644 TABLE OF CONTENTS Epigenetic robotics: modelling cognitive development in robotic systems Pages 189-192 Luc Berthouze and Giorgio Metta http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F1J8FY-1&md5=a6e730dcc6602ce2770e8cc701643a 81 A model of attentional impairments in autism: first steps toward a computational theory Pages 193-204 Petra Bj?rne and Christian Balkenius http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F1J8FY-2&md5=afe39e751a2f591c7804593ab8c193 be Synching models with infants: a perceptual-level model of infant audio-visual synchrony detection Pages 205-228 Christopher G. Prince and George J. Hollich http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F1J8FY-4&md5=c850deee36cbec77da5c4f74a1f74d e8 The evolution of imitation and mirror neurons in adaptive agents Pages 229-242 Elhanan Borenstein and Eytan Ruppin http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F1J8FY-5&md5=de1cc98524ab5133400dd5517f61d4 ec Developmental stages of perception and language acquisition in a perceptually grounded robot Pages 243-259 Peter Ford Dominey and Jean-David Boucher http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F1J8FY-3&md5=34377dba381a57278364f088e0196e 14 ----------------------------------------------------- * Cognitive Systems Research Volume 6, Issue 4, Pages 263-414 (December 2005) http://www.sciencedirect.com/science/issue/ 6595-2005-999939995-606565 TABLE OF CONTENTS When do differences matter? On-line feature extraction through cognitive economy Pages 263-281 David J. Finton http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4D75J5W-1&md5=f4b1ede099fa59af927f3889a2440a dc Experience-grounded semantics: a theory for intelligent systems Pages 282-302 Pei Wang http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4DS9026-1&md5=ff9bf1e90857ffc23559da7b6551e5 b4 A computational model of sequential movement learning with a signal mimicking dopaminergic neuron activities Pages 303-311 Wei Li, Jinghong Li and Jeffrey D. Johnson http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F6MD7G-1&md5=5a3931fac34ae635e9b20351099db8 6e Understanding dynamic and static displays: using images to reason dynamically Pages 312-319 Sally Bogacz and J. Gregory Trafton http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4F6MD7G-2&md5=4c972633b54440549b2f68e1364eeb c1 An artificial intelligent counter Pages 320-332 Qi Zhang http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4FC3RM2-1&md5=253bfa0ee88d958aa530f8c21a1c56 e1 A cognitive model in which representations are images Pages 333-363 Janet Aisbett and Greg Gibbon http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4G7DY66-1&md5=161bdebeb758393bff6c205669790d d1 Agent communication pragmatics: the cognitive coherence approach Pages 364-395 Philippe Pasquier and Brahim Chaib-draa http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4GFVMN2-1&md5=89fa97ee6fe4ca2be7218d541fc557 93 Book reviews Review of Reductionism and the Development of Knowledge, T. Brown & L. Smith (Eds.); Mahwah, NJ: Lawrence Erlbaum, 2002. Pages 396-401 Geert Jan Boudewijnse http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4DN9DVP-3&md5=1af463f1abb48bb5c9a52887ad8d3c 29 Review of the Evolution and Function of Cognition, Lawrence Erlbaum (2003). Pages 402-404 D.M. Bernad http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4GP1VTX-1&md5=3581f5241a551708269892dfbd351b a8 Andy Clark, Natural-born Cyborgs: Minds, Technologies, and the Future of Human Intelligence, Oxford University Press (2003). Pages 405-409 Leslie Marsh http://www.sciencedirect.com/science? _ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDVIALERTASC II&_version=1&_uoikey=B6W6C-4GJKTYX-1&md5=979c0fe014ed250a68b682a37e9e5c b8 ------------------------------------------------------------------------ ---------- See http://www.elsevier.com/locate/cogsys for further information regarding accessing these articles See the following Web page for submission, subscription, and other information regarding Cognitive Systems Research: http://www.cogsci.rpi.edu/~rsun/journal.html If you have questions about features of ScienceDirect, please access the ScienceDirect Info Site at http://www.info.sciencedirect.com ======================================================== Professor Ron Sun Cognitive Science Department Rensselaer Polytechnic Institute 110 Eighth Street, Carnegie 302A Troy, NY 12180, USA phone: 518-276-3409 fax: 518-276-3017 email: rsun at rpi.edu web: http://www.cogsci.rpi.edu/~rsun ======================================================= From Jerry.Ball at mesa.afmc.af.mil Tue Oct 25 14:33:02 2005 From: Jerry.Ball at mesa.afmc.af.mil (Jerry.Ball at mesa.afmc.af.mil) Date: Tue, 25 Oct 2005 11:33:02 -0700 Subject: [ACT-R-users] Spreading Activation in ACT-R Message-ID: <671474002216D14B8D440C71877F9A8D02392806@fsqbge07.williams.afmc.ds.amfc.af.mil> In ACT-R, the activation of a DM chunk is a combination of the base level activation and the source activation spread from buffers in the focus of attention. The activation of all DM chunks (consistent with the retrieval template) is computed (in parallel) at the time of a retrieval and the most highly activated chunk is retrieved (subject to noise). It has recently been brought to my attention that there is no carryover of source activation from DM retrieval to DM retrieval. The source activation is recomputed on each retrieval given the contents of the buffers at the time of the retrieval. On the assumption that base level activations reach asymptote for frequently used DM chunks (following the power law of learning), it is unclear how base level activation alone can account for recency effects of DM chunks which have reached asymptote, since changes in base level will be "in the noise". Something like carryover source activation would appear to be needed. As a practical example of where carryover source activation would be useful, considering the recognition of idiomatic expressions like "kicked the bucket". At the processing of the word "bucket", recognition of the idiom "kicked the bucket" instead of just the word "bucket" requires activation from both "kicked" and "bucket". With carryover source activation, the activation of "kicked the bucket" by "kicked" would carryover to the activation of "kicked the bucket" by "bucket". Without carryover source activation, it will be necessary for "kicked" to remain in the focus of attention along with "bucket" in order to spread source activation to "kicked the bucket". More generally, whenever a composite chunk is competing with noncomposite chunks (e.g. words vs. letters, phrases vs. words, objects vs. features, collections vs. individuals), without carryover of source activation, the elements of the composite chunk will need to be retained in the focus of attention to activate the composite chunk given the current implementation of spreading activation (and assuming retrievals are not specific to the composite type). So long as composite chunks are limited to a few slots and values, retaining the noncomposite chunks in the focus of attention should work to activate the composite chunk. However, carryover source activation offers an alternative to this approach. Speculating on other potential uses of carryover source activation, whereas long-term learning would presumably be reflected in base level activations, short term learning effects might involve an interaction of base level and carryover source activation. This could provide an explanation for spacing effects in learning and the discontinuity in the rate of decay that is often found across short and longer time frames. Even more speculatively, carryover source activation might be viewed as residual neural activity akin to Grossberg's notion of resonance, whereas base level activation results from long term changes in neural potentiation. Jerry -------------- next part -------------- An HTML attachment was scrubbed... URL: From tkelley at arl.army.mil Tue Oct 25 15:58:44 2005 From: tkelley at arl.army.mil (Kelley, Troy (Civ,ARL/HRED)) Date: Tue, 25 Oct 2005 15:58:44 -0400 Subject: [ACT-R-users] Spreading Activation in ACT-R Message-ID: More generally, whenever a composite chunk is competing with noncomposite chunks (e.g. words vs. letters, phrases vs. words, objects vs. features, collections vs. individuals), without carryover of source activation, the elements of the composite chunk will need to be retained in the focus of attention to activate the composite chunk given the current implementation of spreading activation (and assuming retrievals are not specific to the composite type). So long as composite chunks are limited to a few slots and values, retaining the noncomposite chunks in the focus of attention should work to activate the composite chunk. However, carryover source activation offers an alternative to this approach. I think a composite chunk would be the best way to handle the problem in the current implementation. And, the problem of a composite chunk competing with a noncomposite chunk would seem to go away if the activation levels were higher for composite chunks. For example, after seeing the group of words, "kicked the bucket" repeatedly, act-r could create a new chunk for the entire phrase out of separate chunks for each word, based on activation levels. This could be done at the production system level, but it would also be interesting to have this as an architectural feature as well. Anyway, at that point, you could assume a higher level of activation for the composite chunk, "kicked the bucket", as compared to a lower less occurring word like, "gubernatorial". Furthermore, spreading activation can be thought of as a computational approach to context. So, reading a paragraph about someone's impending demise would spread activation to phrases like "kicked the bucket" rather than "kicked the can". All that being said, I like the idea of carryover of source activation. In ACT-R, the activation of a DM chunk is a combination of the base level activation and the source activation spread from buffers in the focus of attention. The activation of all DM chunks (consistent with the retrieval template) is computed (in parallel) at the time of a retrieval and the most highly activated chunk is retrieved (subject to noise). It has recently been brought to my attention that there is no carryover of source activation from DM retrieval to DM retrieval. The source activation is recomputed on each retrieval given the contents of the buffers at the time of the retrieval. On the assumption that base level activations reach asymptote for frequently used DM chunks (following the power law of learning), it is unclear how base level activation alone can account for recency effects of DM chunks which have reached asymptote, since changes in base level will be "in the noise". Something like carryover source activation would appear to be needed. The asymptotic nature of the activation equation can be a little problematic given the task. I have been looking at developing an architecture that has various levels of activation or decay for different memory chunks within the same model. Basically, some memories activate or decay much faster than others depending on the type of memory they are (i.e. perceptual, low level memories decay faster than high level conceptual memories). This allows some more control over when the memory reaches asymptotic levels. I have also been looking at using a "return-to-zero" function, so that once a memory asymptotes, it can be "reset" to zero depending on the situation. This would simulate the effect of a low-level neuron which fires, goes through a refractory period (similar to the asymptotic part of the activation function), then eventually returns to "zero" where it can then fire again starting from zero. I am not saying that all memory functions this way, or that memories are the same as neurons firing, but it is a useful function to have when modeling memory. Troy Kelley U.S. Army Research Laboratory Human Research and Engineering Directorate AMSRD-ARL-HR-SE, APG, MD 21005-5425 Voice: 410-278-5859 email: tkelley at arl.army.mil _____ From: act-r-users-bounces at act-r.psy.cmu.edu [mailto:act-r-users-bounces at act-r.psy.cmu.edu] On Behalf Of Jerry.Ball at mesa.afmc.af.mil Sent: Tuesday, October 25, 2005 2:33 PM To: act-r-users+ at andrew.cmu.edu Subject: [ACT-R-users] Spreading Activation in ACT-R In ACT-R, the activation of a DM chunk is a combination of the base level activation and the source activation spread from buffers in the focus of attention. The activation of all DM chunks (consistent with the retrieval template) is computed (in parallel) at the time of a retrieval and the most highly activated chunk is retrieved (subject to noise). It has recently been brought to my attention that there is no carryover of source activation from DM retrieval to DM retrieval. The source activation is recomputed on each retrieval given the contents of the buffers at the time of the retrieval. On the assumption that base level activations reach asymptote for frequently used DM chunks (following the power law of learning), it is unclear how base level activation alone can account for recency effects of DM chunks which have reached asymptote, since changes in base level will be "in the noise". Something like carryover source activation would appear to be needed. As a practical example of where carryover source activation would be useful, considering the recognition of idiomatic expressions like "kicked the bucket". At the processing of the word "bucket", recognition of the idiom "kicked the bucket" instead of just the word "bucket" requires activation from both "kicked" and "bucket". With carryover source activation, the activation of "kicked the bucket" by "kicked" would carryover to the activation of "kicked the bucket" by "bucket". Without carryover source activation, it will be necessary for "kicked" to remain in the focus of attention along with "bucket" in order to spread source activation to "kicked the bucket". More generally, whenever a composite chunk is competing with noncomposite chunks (e.g. words vs. letters, phrases vs. words, objects vs. features, collections vs. individuals), without carryover of source activation, the elements of the composite chunk will need to be retained in the focus of attention to activate the composite chunk given the current implementation of spreading activation (and assuming retrievals are not specific to the composite type). So long as composite chunks are limited to a few slots and values, retaining the noncomposite chunks in the focus of attention should work to activate the composite chunk. However, carryover source activation offers an alternative to this approach. Speculating on other potential uses of carryover source activation, whereas long-term learning would presumably be reflected in base level activations, short term learning effects might involve an interaction of base level and carryover source activation. This could provide an explanation for spacing effects in learning and the discontinuity in the rate of decay that is often found across short and longer time frames. Even more speculatively, carryover source activation might be viewed as residual neural activity akin to Grossberg's notion of resonance, whereas base level activation results from long term changes in neural potentiation. Jerry -------------- next part -------------- An HTML attachment was scrubbed... URL: From nthinh at nats.informatik.uni-hamburg.de Thu Oct 27 12:14:14 2005 From: nthinh at nats.informatik.uni-hamburg.de (Le Nguyen-Thinh) Date: Thu, 27 Oct 2005 18:14:14 +0200 Subject: [ACT-R-users] The LISP tutor, The Prolog Tutor Message-ID: <4360FCD6.5000606@nats.informatik.uni-hamburg.de> Dear colleagues, i am really keen to test the Lisp tutor and the Prolog tutor developed by the ACT group. Could any one please give me some information how i can do it. Thank you a lot. Thinh From jjoshi at mail.sis.pitt.edu Sat Oct 29 14:59:31 2005 From: jjoshi at mail.sis.pitt.edu (James Joshi ) Date: Sat, 29 Oct 2005 14:59:31 -0400 Subject: [ACT-R-users] CFP: Workshop on Information Assurance (WIA 2006) Message-ID: <000001c5dcbb$993ca250$5c748e88@GRBAC> Workshop on Information Assurance (WIA 2006) In conjunction with the 25th IEEE International Performance Computing and Communications Conference (IPCCC) http://ipccc.org/ Phoenix, Arizona, April 10-12, 2006 Keynote Speaker: Dr. Carl E. Landwehr, Program Manager, Advanced Research and Development Agency Scope: Information Assurance (IA) is defined as the operations undertaken to protect and defend information and information systems by ensuring their availability, integrity, authentication, confidentiality and non-repudiation. Availability implies that networks and systems must be survivable and fault tolerant - they should possess redundancies to operate under failures or security breaches. For example, networks should be designed with sufficient spare and working capacity, efficient traffic restoration protocols, alarms and network management. Security encompasses the other aspects of IA, namely integrity, access-control, authentication, confidentiality and non-repudiation as they apply to both networks and systems. The increasing reliance of business-to-business and business-to-consumer applications on networked information systems dramatically magnifies the consequence of damages resulting from even simple system faults and intrusions, making the task of assuring confidentiality, availability and integrity of information difficult. Although several piecemeal solutions address concerns related to the security and fault tolerance of various components of such networked information systems, there is a growing need to leverage the synergy between security and survivability to provide a higher level of information assurance in the face of faults and attacks. We seek papers that address theoretical, experimental, systems-related and work in-progress in the area of Information Assurance at the network and system levels. We expect to have three types of sessions - the first related to survivability and fault tolerance, the second related to security, and the third related to the interactions between security and survivability. Papers should describe original, previously unpublished work, not currently under review by another conference, workshop, or journal. Papers accepted for presentation will be published in the IPCCC conference proceedings. The workshop will also include invited papers. Topics of interest include, but are not limited to: Authorization and access-control Web services security Database and system security Risk analysis and security management Security verification/validation Wireless LAN Security Network Restoration techniques Network Reliability/Availability Digital Rights Management DoS protection for the Internet Cryptographic protocols and Key management Intrusion Detection Techniques Ad hoc sensor network security Models and architectures for systems security and survivability Security and survivability in optical networks E/M-commerce security and survivability architectures Public policy issues for security and survivability Instructions for authors: Papers reporting original and unpublished research results on the above and related topics are solicited. All submitted papers will be refereed for quality, originality and relevance by the Program Committee. The acceptance/rejection of the papers will be based on the review results. All questions should be addressed to the PC co-chairs. Authors are encouraged to submit their papers electronically. An electronic version (PDF format) of the paper should be submitted by November 22, 2005 to the workshop website. Manuscripts should be in English and must not exceed 8 pages (IEEE format) for regular papers and 4 pages (IEEE format) for short papers. Short papers will be included for presentation in a poster session. A cover page must include a title, descriptive keywords, all author's names, complete mailing addresses, telephone numbers, e-mail addresses and an abstract of up to 150 words. Both regular and short papers accepted for presentation will be published in the IPCCC conference proceedings. For any further information, please check the workshop web page at http://www.sis.pitt.edu/~lersais/WIA2006/ or send e-mail to one of the program co-chairs. Inviting selected papers for an edited book is being planned General Chair David Tipper (dtipper at mail.sis.pitt.edu ) Program Co-chairs: James Joshi (jjoshi at mail.sis.pitt.edu) Prashant Krishnamurthy (prashant at mail.sis.pitt.edu) Yi Qian (yqian at ece.uprm.edu) Jun Wang (wangj at pecos.ncsa.uiuc.edu) William Yurcik (byurcik at ncsa.uiuc.edu) Important Dates: Deadlines for Submissions: November 22nd, 2005 Notification of Acceptance: January 10th, 2006 Camera-Ready Copy Received: January 26th, 2006 -------------- next part -------------- An HTML attachment was scrubbed... URL: