simulation@uflorida.cis.ufl.edu (Moderator: Paul Fishwick) (09/17/88)
Volume: 5, Issue: 1, Fri Sep 16 17:17:13 EDT 1988 +----------------+ | TODAY'S TOPICS | +----------------+ (1) Non-Linear System Behavior (2) State and Change/ Continuous Actions Moderator: Paul Fishwick, Univ. of Florida Send topical mail to: simulation@uflorida.cis.ufl.edu ----------------------------------------------------------------------------- Date: Fri, 16 Sep 88 12:04:23 PDT From: Eugene Miya <eugene@eos.arc.nasa.gov> To: simulation@uflorida.cis.ufl.edu Subject: Re: Non-linear system behavior Huberman sent me mail about this article, and he is apparently swamped with inquires. My suggestion is to get his collection of papers from North-Holland entitled the Ecology of Computation [1988]. No: the issue isn't just one of floating point rounding or experimental design, but I withhold further comment to hear what others have to say. --eugene miya p.s. the book is interesting, I've only seen Bernardo's copy, it is available locality at Staceys (Stanford) I've not seen it at Computer Literacy yet [they are behind on orders due to swampage]. ------------------------------ To: comp-simulation@ufl.edu Path: uflorida!fish.cis.ufl.edu!fishwick From: fishwick@fish.cis.ufl.edu (Paul Fishwick) Newsgroups: comp.ai,comp.simulation,sci.math Subject: State and Change/ Continuous Actions Date: 16 Sep 88 21:14:21 GMT Sender: news@bikini.cis.ufl.edu Reply-To: fishwick@fish.cis.ufl.edu () Organization: UF CIS Department An inquiry into concepts of "state" and "change": In browsing through Genesereth's and Nilsson's recent book "Logical Foundations of Artificial Intelligence," I find it interesting to compare and contrast the concepts described in Chapter 11 - "State and Change" with state/change concepts defined within systems theory and simulation modeling. The authors make the following statement: "Insufficient attention has been paid to the problem of continuous actions." Now, a question that immediately comes to mind is "What problem?" Perhaps, they are referring to the problem of defining semantics for "how humans think about continuous actions." This leads to some interesting questions: 1) Clearly, the vast literature on math modeling is indicative of "how humans think about continuous actions." This knowledge is in a compiled form, and use of this knowledge has served science in an untold number of circumstances. 2) If commonsense knowledge representation is the issue then we might want to ask a fundamental question "Why do we care about representing commonsense knowledge about continuous actions?" I can see 2 possible goals: One goal is to validate some given theory of commonsense "continuous action" knowledge against actual psychological data. Then we could say, for instance, that Theory XYZ reflects human thought and is therefore useful. I don't think it would be useful to increase our knowledge of mechanics or fluidics, for instance, but perhaps a psycho-therapist might find this knowledge useful. A second goal is to obtain a better model of the continuous action (this reflects the "AI is an approach to problem solving" method where one can study "how Johnny reasons when balls are bounced" and obtain a scientifically superior model regardless of its actual psychological validity). Has anyone seen a commonsense model of continuous action that is an improvement over systems of differential equations, graph based queueing models (and other assorted formal languages for systems and simulation)? Obviously, I'm trying to spark some inter-group discussion and so I hope that any responses will post to both the AI group (comp.ai) AND the SIMULATION group (comp.simulation). In addition (sci.math) and (comp.theory.dynamic-sys) may be appropriate. I believe that Genesereth and Nilsson are quite correct that "reasoning about time and continous actions" is an important issue. However, an even more important issue revolves around people discussing concepts about "state," "time," and "change" by crossing disciplines. Any thoughts? -paul +------------------------------------------------------------------------+ | Prof. Paul A. Fishwick.... INTERNET: fishwick@bikini.cis.ufl.edu | | Dept. of Computer Science. UUCP: gatech!uflorida!fishwick | | Univ. of Florida.......... PHONE: (904)-335-8036 | | Bldg. CSE, Room 301....... FAX is available | | Gainesville, FL 32611..... | +------------------------------------------------------------------------+ ------------------------------ +--------------------------+ | END OF SIMULATION DIGEST | +--------------------------+