From cl2e+ at andrew.cmu.edu Wed Aug 2 14:37:17 1995 From: cl2e+ at andrew.cmu.edu (Christian Lebiere) Date: Wed, 2 Aug 1995 14:37:17 -0400 (EDT) Subject: ACT-R 2.1 + Summer School material Message-ID: <0k7wLRe00iVEM3tqwc@andrew.cmu.edu> NOTE: I am leaving on vacation immediately and will be back Sunday night. I will answer all questions/remarks/complaints first thing Monday morning. The latest version of ACT-R and the material used in the just-concluded 1995 Summer School are now available on the usual server(s). Mac versions are available on the server largo.psy.cmu.edu in the directory /public/ACT-R. Text and/or BinHex versions are available on the server ftp.andrew.cmu.edu in the directory /pub/act-r/ftp. A new top-level folder called education has been created in the repository. The file GMU ACT-R Curriculum contains the curriculum of an ACT-R-based course that Wayne Gray taught recently at George Mason University (Thanks, Wayne!). The folder 1995 Summer School contains the summer school material. It comprises 1) the schedule in MS-Word 2) a Hypercard stack (sorry, non-Mac people, I will try to see if there is a Word version) with the text of each lesson, exercises, and assignments 3) eight folders containing for each session one or more examples of relevant ACT-R models and the solution model (text files). This material worked well in the summer school, but still needs improvement. We will be going over it this fall and an updated version should be available this winter. The folder ACT-R 2.1 contains the new version of the system (the previous one was ACT-R 2.0, patch1 and patch2). It is available both as a BinHex version of a Stuffit Archive containing the whole ACT-R folder (as released with the ROM book), and as a Code folder containing the full code in text files. People who ported ACT-R to other Common Lisp implementations should reapply the port to this version rather than attempt to integrate the voluminous change files. The folder Extensions contains some (not all) of those change files. It also contains two sub-folders, return-extension and new analogy, which contain examples of the new mechanism which allow subgoals to return values, and the new analogy mechanism, respectively. The latter also contains an MS-Word manual explaining the new mechanism. ACT-R 2.1 should only display minor differences with ACT-R 2.0 on existing examples, but incorporates a number of further developments. I will attempt to briefly describe them below, while acknowledging that the existing documentation is insufficient and will be remediated upon my return. The best way to learn about them currently would be in the summer school material (or by contacting me). * a number of fixes have been incorporated. The only seriously noticeable difference is that a production attempting to pop the last goal on the stack (typically the last instantiation of the run) can now complete succesfully rather than abort. * ACT-R is now fully operating on a real-time clock. That means that the cycle counter is now a real number starting at 0.0 (instead of 1). If Enable Rational Analysis is turned on, then the matching latency is added to the counter (otherwise nothing). The latency for the rhs (or action latency) is the value of the parameter :a (or :effort) for that production. So when ERA is turned off and the :a parameters are left to their default value of 1.0, we get back the discrete time clock. Our usual value for :a is 0.05 (50 milliseconds if you will). * There is now a way to set initial base level activation independently for each wme, using the SetGeneralBaseLevels and AddGeneralBaseLevels commands. * A subgoal can now return a value to its parent goal, using a generalization of the wme retrieval syntax to the right-hand side. The return-extension folder in Extensions contains examples of its use to compute the factorial and fibonacci function. * Activation-wise, elements (i.e. slot value which are wmes) of the goal are now the default sources of activation, instead of the goal itself. The total source level of activation (1.0 by default) is divided evenly among them. Also, the IA value from a wme to itself is now set to the same value as the IAs from that element to any other (i.e. direct retrievals are now treated the same as indirect ones). * The new analogy mechanism which had been in beta test for several months has now become standard. The New Analogy folder in Extensions contains a brief manual describing its use, and two folders: a folder of the previously developed analogy models unchanged, and a folder containing those examples sometimes modified to run under the new mechanism. In addition, the partial matching mechanism is now available as an extension to the standard system (partial-matching.lisp in folder Extensions) to be loaded as needed, as it is still a bit too unstable to be integrated in the standard system. Our Cogsci 94 paper ("Error modeling in the ACT-R production system", by Lebiere, Anderson and Reder) introduces the general mechanism, and the summer school material describes how to use it. As was discussed extensively at the ACT-R Worskhop, this is the last major upgrade of the current system, ACT-R 2.x. We will keep supporting this system, but have started work on its successor, ACT-R 3.0, which will incorporate the restrictions and stylistic guidelines that were discussed at the workshop, in a more efficient and flexible implementation with a more useful, user-friendly environment. More about that later on this list. Again, feel free to send me any problem/comment/suggestion. I will be out until Monday, but will answer my email as soon as I come back. Christian From gray at gmu.edu Tue Aug 29 13:07:50 1995 From: gray at gmu.edu (Wayne Gray) Date: Tue, 29 Aug 1995 13:07:50 -0400 Subject: Immediate job opportunity Message-ID: Greetings to all. A colleague, Debbie Boehm-Davis, is posting a job that you might be of interest to someone on this mailing list, though just reading the description you might think to pass it by. It is an interesting position. While she is asking for expertise in many different areas (including aviation/transporation systems) she is essentially looking for an Applied Cognitive type who can manage her current projects and write. Her goal is to have this person, eventually, be working 50% of the time on her projects and 50% of the time on their own grants. It is soft money but it is guaranteed funding at 100% for two years. After that it depends upon the ability of Debbie and whoever she hires to write grants and get money. She is really interested in someone who knows how to write (as evidenced by research publications) and is interested in pushing the "applied cognitive" agenda forward. Both of us would like to work with this person to submit joint proposals. This would be a great "post-doc" type position for the right person. BTW: the Psych dept is committed to hiring a new, permanent "applied cognitive" type. We have general approval from the university on this and expect to begin the search next academic year. If the Research Psychologist were the right person, I (and probably Debbie) would encourage them to apply for the faculty position when it became available. ################################## Research Psychologist wanted to conduct and manage research in human factors and applied cognition. Experience in aviation/transportation systems and software psychology preferred. The successful applicant will have a PHD plus three years experience in writing research proposals and in conducting and managing applied psychological research. Teaching experience an asset. Send letter of application, vita, and three references to Dr. Deborah A. Boehm-Davis, Chair, Search Committee, MSN 3A2, George Mason University, Fairfax, VA 22030-4444. Review of applications will be immediately and continue until the position is filled. GMU is an Equal Employment Opportunity/Affirmative Action Employer. #=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#= Wayne D. Gray Human Factors & Applied Cognitive Program George Mason University m/s 3f5 Fairfax, VA 22030 NOTE THAT MY PHONE NUMBER HAS BEEN CAPRICIOUSLY CHANGED: NEW NUMBER: +1 (703) 993-1357 Everything else remains the same. #=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#=#= From cl+ at andrew.cmu.edu Thu Aug 31 09:16:33 1995 From: cl+ at andrew.cmu.edu (Christian Lebiere) Date: Thu, 31 Aug 1995 09:16:33 -0400 (EDT) Subject: Vacation Message-ID: I am leaving on vacation today and will be back Monday September 11. Email to act-r-users-request will be answered first thing monday morning. Christian From trafton at itd.nrl.navy.mil Tue Aug 1 18:02:45 1995 From: trafton at itd.nrl.navy.mil (Greg Trafton) Date: Tue, 1 Aug 95 18:02:45 EDT Subject: ACT-R FAQ Message-ID: <9508012202.AA26758@itd.nrl.navy.mil> For those of you who were not at the ACT-R workshop, one of the things we talked about was how to make ACT-R easier to use. The good news: there are several projects that are underway to facilitate ACT-R (tutor, 'graphing' system, etc.). However, for those of us who needed (or still need) more hand-holding, I would like to put together a "Frequently Asked Questions" for ACT-R. (How can we have an FAQ since this list sees so little traffic? I dunno.) I've volunteered (with Christian's help) for this project, but I need your help. I'd very much like to get a list of questions that you think that novice and experienced ACT-R folks would kill to know the answer. Personally, I'd like to keep it more on the 'pragmatic' side (i.e., what is a 'negative exponential?) rather than theoretical (i.e., why does ACT-R use procedural and declarative instead of XXX?), but if you all send a lot of theory questions, I'm easy. If you'd like to help, please please please send me any ACT-R questions you may have (no matter how mundane, stupid, sophisticated, or technical). For those of you who are advanced ACT-Rers, if you remember questions you had when you were first starting (or new questions you currently have), I'd love to have them. if anyone can send me answers too, that would be really great ;-> my email address is: trafton at itd.nrl.navy.mil thanks for any help! greg