nl-kr-request@cs.rpi.edu (NL-KR Moderator Chris Welty) (11/30/89)
NL-KR Digest (Thu Nov 30 09:54:34 1989) Volume 6 No. 45 Today's Topics: ATMS Implementation Query (Long) AI Seminar Finding Spatial Relations in the World ... (Unisys AI seminar) CSLI Calendar, 30 November, vol. 5:10 Submissions: nl-kr@cs.rpi.edu Requests, policy: nl-kr-request@cs.rpi.edu Back issues are available from host archive.cs.rpi.edu [128.213.1.10] in the files nl-kr/Vxx/Nyy (ie nl-kr/V01/N01 for V1#1), mail requests will not be promptly satisfied. If you can't reach `cs.rpi.edu' you may want to use `turing.cs.rpi.edu' instead. BITNET subscribers: we now have a LISTSERVer for nl-kr. You may send submissions to NL-KR@RPIECS and any listserv-style administrative requests to LISTSERV@RPIECS. [[ The Symbol Grounding Problem has once again become a hot topic on comp.ai, and it does fall under the topics this list covers. Because I have no way of objectively filtering the discussion, I decided to include only the first two articles (which were in the last issue) and point people interested in reading more to comp.ai. For those who do not have USENET access, I am keeping all the articles in that discussion. It is currently 52K of text and still raging. The file is in nl-kr/sgp on the archive server. -CW ]] ----------------------------------------------------------------- To: nl-kr@cs.rpi.edu >From: sce!sce.carleton.ca!bond@watmath.waterloo.edu (Greg Bond) Newsgroups: comp.ai,comp.ai.nlang-know-rep Subject: ATMS Implementation Query (Long) Date: 29 Nov 89 01:05:25 GMT I'm in the midst of designing an ATMS and have run into difficulties surmising implementation details of constraint consumers from deKleer's third paper (Problem Solving with the ATMS). The explanation of my problem is rather involved but I would appreciate any help I can get (in the form of advice or pointers to papers, tech reports or books) because any solution to the problem I can think of is rather kludgy - kludges do not belong in as elegant a mechanism as the ATMS! My difficulties can be illustrated with a simple example: suppose I wish to add a constraint consumer for the problem solver constraint x=y+z. Using deKleer's notation, this amounts to a set of conjunctive class consumers y,z |-> {x=y+z}; x,y |-> {z=x-y}; x,z |-> {y=x-z} with a type C. Given that this constraint consumer has been installed in the ATMS and the ATMS database is initially empty (no nodes or justifications asserted), the following scenario unfolds: first, a premise node with datum y=2 is asserted by the problem solver - the returned node and its datum are entered in a problem solver lookup table to prevent the assertion of multiple ATMS nodes with the same datum; then a premise node with datum z=3 is asserted and its node is entered in the lookup table. At this point the conjunctive class consumer y,z |-> {x=y+z} is enqueued (by a problem solver-supplied enqueue procedure) for execution (by a consumer execution procedure internal to the ATMS). When executed, the consumer derives the datum x=5 and asserts a corresponding node in the ATMS. The datum and its node are entered in the problem solver lookup table and the node is returned to the consumer execution procedure where a justification for the node is asserted - in this case, the premises with datums y=2, z=3 are the antecedents and the node with datum x=5 is the consequent. The justification informant indicates the consequent being a result of a consumer of type C. Herein lie the problems. At first, I thought that conjunctive class consumers should be checked for applicability when a node is asserted. Thus, when a node is asserted through the standard ATMS add-node interface procedure, any conjunctive class consumers with domain classes corresponding to that of the newly asserted node and any existing nodes in the ATMS database are applicable. If the node conjuncts hold in consistent environments then the consumer is enqueued. This technique works fine for triggering the consumer in the given example: the node for y=2 belongs to variable class y and the node for z=3 belongs to class z - conjunctive class consumer y,z |-> {x=y+z} is therefore applicable. However, when the consumer asserts the newly derived node for x=5 the remaining two conjunctive class consumers will be found to be applicable. Since the node label for x=5 is empty until it is justified the applicable consumers cannot be enqueued. Instead, two dummy nodes are asserted with the respective consumers attached to them. The dummy nodes are then justified by the respective antecedent nodes: x=5,y=2 justifying the dummy node with consumer x,y |-> {z=x-y} attached and x=5,z=3 justifying the dummy node with consumer x,z |-> {y=x-z} attached. When the node for x=5 is justified by the ATMS consumer execution procedure, both of the dummy nodes' labels are updated to non-empty but neither of the attached consumers are enqueued because their type is the same as that justifying the antecedent node for x=5. The problem is that these dummy nodes and their justifications should never have been added to the ATMS in the first place because their attached consumers will never run. The ATMS is left with a couple of extra nodes (in this small example) whose labels are updated along with the other node labels for no purpose whatsoever. How is this exception handled gracefully? Is my current interpretation of the ATMS mixed up or is it simply a matter of passing extra parameters around (flags -> yuk!)? - ----------------------------------------------------------------- Greg Bond -----> bond@sce.carleton.ca Dept. of Systems and Computer Engineering, Carleton University Ottawa, ON, Canada K1S 5B6 ------------------------------ To: nl-kr@cs.rpi.edu Date: Tue, 28 Nov 89 14:45 EDT >From: MMETEER@rcca.bbn.com Subject: AI Seminar BBN STC Science Development Program AI Seminar Series Lecture SEMANTIC INTERPRETATION AND THE LEXICON: WHAT MAKES SENSE? Paul S. Jacobs AI Program, GE Research Schenectady, NY 12301 USA jacobs@crd.ge.com BBN STC, 2nd Floor Conference Room 10 Moulton Street, Cambridge, Massachusetts Tuesday, December 5, 10:30 am Practical applications of natural language demand precision in semantic interpretation, highlighting the problems of lexical ambiguity and vagueness. The representation and discrimination of word meanings is thus a key issue for language analysis, motivated especially by the need for broad scale NL systems and by applications in information retrieval. A successful method for distinguishing word senses, however coarsely, could be a major contribution to natural language processing technology. Past research does not point to a successful strategy for sense discrimination, but it does reveal some naive approaches that won't work. The most obvious of these is the simple search for intersections or ``lexical coherence'' among word sense categories. This twenty-year-old approach is still popular and still destined to fail. Sense discrimination depends on context, and context is more than the combination of the words that appear together. Context comprises topic analysis, phrasal constructs, complex events, and linguistic and conceptual structures. This research focuses on accessing the power of these more complex contextual structures in identifying word senses using a lexicon of over 10,000 roots. Semantic and syntactic preferences, lexical relations, and other structural knowledge combine in our approach to help with generic sense discrimination. ------------------------------ To: nl-kr@cs.rpi.edu Date: Wed, 29 Nov 89 11:08:49 -0500 >From: finin@PRC.Unisys.COM Subject: Finding Spatial Relations in the World ... (Unisys AI seminar) AI SEMINAR UNISYS PAOLI RESEARCH CENTER Finding Spatial Relations in the World to Match our Prepositions Annette Herskovits Wellesley College and University of Pennsylvania Lexical meanings are notoriously difficult to define. For any definition, there seems to exist a counterexample. Focusing on spatial prepositions ("across", "at", "over", etc.), I will propose systematic, but quite complex, interactions between word meaning and cognition to account for the broad range of uses of a word. I will assume a geometric schema associated with each spatial preposition, but also active processes of fitting the schema onto real situations. Two phenomena account for the flexibility of lexical use: first, the fitting takes advantage of selections, groupings, idealizations, and tranformations which are part and parcel of spatial cognition (rather than strictly linguistic processes); second, approximate fits are acceptable, subject to well-defined conditions. However, this search for a best fitting schema cannot explain all prepositional uses. In addition, there are some standard types of situation, defined as functional interactions rather than strictly spatially, for which the use of a particular preposition is required, either by convention or because of salience. I will discuss the consequences of this analysis for linguistics and artificial intelligence. 11:00 pm Tuesday, December 5, 1989 BIC Conference Room Unisys Paoli Research Center Route 252 and Central Ave. Paoli PA 19311 -- non-Unisys visitors who are interested in attending should -- -- send email to finin@prc.unisys.com or call 215-648-7446 -- ------------------------------ To: nl-kr@cs.rpi.edu Date: Wed, 29 Nov 89 13:43:04 PST >From: ingrid@russell.Stanford.EDU (Ingrid Deiwiks) Subject: CSLI Calendar, 30 November, vol. 5:10 C S L I C A L E N D A R O F P U B L I C E V E N T S - ---------------------------------------------------------------------------- 30 November 1989 Stanford Vol. 5, No. 10 _____________________________________________________________________________ A weekly publication of the Center for the Study of Language and Information (CSLI), Ventura Hall, Stanford University, Stanford, CA 94305-4115 ____________ CSLI ACTIVITIES FOR THIS THURSDAY, 30 NOVEMBER 1989 12:00 noon TINLunch Cordura 100 Stanford's Policies on Intellectual Property Rights Jon Sandelin and David Charron, Licensing Associates Jane McLean, Manager of the Software Distribution Center (SDC) Office of Technology Licensing (OTL) Stanford University (sandelin@popserver.stanford.edu) Abstract in last Calendar 2:15 p.m. CSLI Seminar Cordura 100 Models of Rational Agency 9 Michael Bratman, Martha Pollack, Stan Rosenschein (bratman@csli.stanford.edu, pollack@warbucks.ai.sri.com, stan@teleos.com) Wrap-up session Abstract in last Calendar ____________ ANNOUNCEMENT Because of final exams and the winter break, there will be no Thursday events and no Calendar on 7, 14, 21, and 28 December. The next Calendar will be published on 4 January, and Thursday events will resume on 11 January. ____________ SYMBOLIC SYSTEMS FORUM Systematizing Our Commonsense Reasoning about Fictions Ed Zalta Friday, 1 December, 3:15, 60-61G Consider this piece of reasoning: (1) The ancient Greeks worshipped Dionysus. (2) Dionysus is a mythical character. (3) Mythical characters don't exist. (4) Therefore, the ancient Greeks worshipped something that doesn't exist. Even though we are tempted to say that the Greeks certainly believed that they were worshipping something that exists, if (2) and (3) are true, what they were worshipping doesn't exist. How, then, do you represent (4) using the resources of ordinary logic? How can you say that there is something which doesn't exist and which the Greeks worshipped? Haven't you contradicted yourself? Moreover, it follows from the fact that Ponce de Leon searched for the fountain of youth that Ponce de Leon searched for something. What is the thing that makes "Ponce de Leon searched for something" true? These are questions addressed in Friday's talk. This talk is aimed at undergraduates with no assumed background. Refreshments will be served. ____________ PHILOSOPHY DEPARTMENT COLLOQUIUM Warranted Assertibility and Truth: Dewey's Reply to Russell Tom Burke Department of Philosophy (burke@csli.stanford.edu) Friday, 1 December, 3:15, 90-91A Russell (1940) wants to say that a proposition expressed by the formula `P(a)' is true just in case the object a denoted by `a' does in fact have the property P denoted by `P'. True propositions simply report facts. This assumes that a and P occur in the actual scheme of things, hence the only real question as to the truth-value of the proposition is whether or not a does in fact have property P. Russell admits that this "involves us in metaphysics, and has difficulties (not insuperable) in defining the correspondence which it requires for the definition of `truth'." Dewey assumes virtually nothing about "_the_ actual scheme of things," in which case a simple appeal to facts is pointless. Dewey relativizes the propositional contents of statements to schemes of individuation I brought to bear by agents in given situations s (to use some current terminology). The proposition that a is of kind P (modulo s,I) is true just in case (1) a and P belong to the individuation scheme I brought to bear in situation s, and (2) the activities perform _able_ in that situation to individuate object a _would in the ideal limit_ reliably indicate that it meets the specifications for being of kind P (whether or not those activities are actually performed). I will discuss several examples to motivate this pragmatist definition of truth. ____________ COMMONSENSE AND NONMONOTONIC REASONING SEMINAR A New Approach to Modal Operators Matt Ginsberg Department of Computer Science Monday, 4 December, 3:15 Margaret Jacks Hall 252 We describe a new formalization of modal operators that views them not in terms of Kripke's possible worlds, but as functions on an underlying set of truth-values. Thus Moore's knowledge operator L, where Lp means "I know that p," would correspond to a mapping taking true into true (since we know p if we know it to be true) and taking both false and unknown into false (since we do not know p if we either know it to be false or know nothing about it at all). This new approach has the following advantages over the conventional ones: (1) intuitive simplicity; (2) it provably generalizes both Kripke's construction and Moore's autoepistemic logic, while making clear the distinctions between them; (3) it allows for easy further generalization to modal operators that are related to temporal reasoning and to causality; (4) the natural procedure for computing the truth-value of a sentence involving these modal operators is "incremental" in the sense that it computes approximate answers that "converge" to the correct one in the large runtime limit. This talk will concentrate on the first two of these properties; I will discuss the third and fourth as completely as time allows. ____________ SPECIAL TALK Nonwellfounded Sets and Their Applications Jon Barwise Monday, 11 December, 4:00 SRI International, Building A, Conference Room B Nonwellfounded sets (for example, a stream of the form a = (1,(2,a)), with the usual definition of ordered pair) were part of set theory in the good old days, but were later banned since they were felt to be implicated in the paradoxes. However, in recent years, they have been slowly finding their way back into set theory, due in part to the work of Peter Aczel (among others), who has shown that they are not incoherent, and in part to applications that have been found for them in modeling various kinds of circular phenomena in computer science, AI, philosophy, and cognitive science. This talk will motivate nonwellfounded sets by focusing on simple applications in computer science. I will then give a summary of Aczel's work, and show how it yields the desired applications. The talk is expository and should be accessible to anyone familiar with basic set theory. - -- Note for Visitors to SRI: Please arrive at least ten minutes early in order to sign in and be shown to the conference room. SRI is located at 333 Ravenswood Avenue in Menlo Park. Visitors may park in the visitors lot in front of Building A (red brick building at 333 Ravenswood Avenue, second driveway on the right, east of Laurel) or in the conference parking area at the corner of Ravenswood and Middlefield. The seminar room is in building A. Visitors should sign in at the reception desk in the building A lobby. IMPORTANT: Attendance is open, but visitors from certain countries designated by the U.S. government must make arrangements in advance. If you have not already made such arrangements before your arrival, admission to the seminar will be denied. If you believe you may be from one of these countries and if you wish to make arrangements to attend, please call Judith Burgess at (415) 859-5924. ____________ CURRENT VISITORS AT CSLI PETER AUSTIN, Senior Lecturer in Linguistics and Japanese Language Coordinator, La Trobe University, Melbourne, Australia. Peter's main research areas are syntax, semantics, and Australian Aboriginal languages. He has published on morphosyntax, case marking, and complex sentence constructions (including switch-reference) in Australian languages. His most recent publication is _Complex Sentence Constructions in Australian Aboriginal Languages_ (Benjamins, 1988). Dates of visit: November 1989-January 1990. SUK-JIN CHANG, Department of Linguistics, Seoul National University. During his stay at CSLI, Suk-Jin will continue to work on developing an information-based Korean discourse grammar (IKDG) that has been conceived of and explored to some extent from the perspective of natural-language processing and in the general theoretical framework of relational theories of language as action. Specifically, he will attempt to incorporate into IKDS the system of honorification, viewed as a pragmatic agreement phenomenon between the discourse participants and the information functions of topic and focus, distinct from grammatical functions of subject and object, by keeping abreast of ongoing studies in situation theory and situation semantics and extending the semantic component of HPSG. Dates of visit: August 1989-July 1990. HIROSHI KATO, Industrial Affiliates Program visiting researcher, C&C Information Technology Laboratories, NEC Corporation, Japan. Since 1983, Hiroshi has been engaged in research and development of educational systems, such as Computer-Based Instruction (CBI) systems and Computer-Managed Instruction (CMI) systems. He is interested in cognitive models of human learning and human interface. He is now working on a research project with James Greeno on a learner's understanding model of first-order logic through the CBI system "Tarski's World." Dates of visit: August 1989-August 1990. FINN KENSING, Associate Professor, Department of Computer Science, Roskilde University Centre, Denmark. Finn is a coauther of _Professional Systems Development: Experience, Ideas and Action_. The book will be published by Prentice Hall this fall. While at CSLI, Finn will be doing an inquiry into what can be learned from applying a language/action approach on the design of systems to be used in human work processes. He will be working closely with Terry Winograd. Dates of visit: August 1989-February 1990. BERNARD LINSKY, Associate Professor of Philosophy, University of Alberta, Canada. Bernie is on sabbatical from Edmonton for the academic year. He is here to learn about situation semantics and to work on papers on the metaphysics of semantics, in particular, on possible worlds and universals. Dates of visit: September 1989-August 1990. HIDEO MIYOSHI, Industrial Affiliates Program visiting researcher, Sharp Corporation, Japan. From 1982 to 1987, Hideo was involved in natural-language processing as a researcher of ICOT (Japanese fifth generation computer project), where he worked on the development of BUP (bottom-up parser in Prolog), DUALS (an experimental discourse-understanding system), and JPSG (Japanese Phrase-Structure Grammar). At SHARP, he recently worked on the development of (1) a text-retrieval system using flexible keywords, and (2) a support system for generating controlled Japanese texts. Both projects were sponsored by ICOT. Hideo is interested in the semantic analyses and representations of the Japanese language. He is also interested in the role and mechanism of knowledge in natural-language understanding. He hopes that the STASS project will help him understand these better. While at CSLI, he will be mainly involved in the STREP project. Dates of visit: October 1989-October 1990. STEPHEN NEALE, Assistant Professor of Philosophy, Princeton University. Stephen is working on a new book on the interpretation of plural noun phrases in natural language, and -- when time permits -- a manuscript on free will. Dates of visit: May 1989-February 1990. MASAYUKI NUMAO, Tokyo Institute of Technology. Masa's research topic is: Learning in Situations. During the last few years, he's been interested in "learning," especially program synthesis by using the techniques of machine learning. Generally speaking, program synthesis systems have only synthesized pure Lisp or pure Prolog programs that do not cause "side effects," since researchers seek "general synthesis schemes." In reality, procedural programs depend completely on each situation, and program statements may depend on each other unexpectedly, causing "frame problems." Masa would like to overcome these difficulties by "analytic learning of situations." The steps are as follows: (1) Learning -- An abstracted environment is extracted by analyzing the situation based on a given PASCAL interpreter, and memorized. (2) Program Synthesis -- In similar situations, slightly modified programs are synthesized. Masa hopes that each situation can be given in natural language as given in PASCAL tutorial books, but as the first step he will give it directly. He thinks "learning" is a key factor when dealing with "situatedness." Dates of visit: September 1989-August 1990. GREG O'HAIR, Department of Philosophy, The Flinders University of South Australia. Dates of visit: October 1989-June 1990. RYO OCHITANI, Industrial Affiliates Program visiting researcher, Fujitsu Laboratories Ltd., Japan. For the past five years, Ryo has helped develop the machine-translation system ATLAS2 at Fujitsu Laboratories. During the last year, he and several other people started a new study on a quicker and easier system to classify sentences based on the semantic view, for which they collected two million Japanese text samples and classified several hundred sentences manually. Ryo is interested in studying what kind of system would utilize this information most efficiently. Dates of visit: April 1989-April 1990. ICHIRO OHSAWA, Tokyo Institute of Technology, Japan. Ichiro's interest is modeling on computers of intelligent and communicative agents who can handle natural language. The two key facts about such agents are perspectivity and situation-boundedness. That is, they view the world and themselves from their points of view and the information they get is given only in the situation they are in. His current research has been aimed at a computational realization of an agent who can interact in dialog with his own viewpoint. He looks forward to active interactions with human intelligent agents at CSLI. Dates of visit: September 1989-February 1990. ELIN ROENBY PEDERSEN, Assistant Professor of Computer Science, Department of Computer and Systems Sciences, Copenhagen School of Business and Administration, Denmark. During her stay, Elin will carry out a number of studies on the use of advanced work stations in intellectual work, e.g., in system analysis and development and in research. The aim of these studies is to get a firmer grip on the dynamical influence of computerized tools on processes in which people attempt to build and convey knowledge. One hypothesis is that the use of computerized tools should be studied as a special case of the use of strictly defined means for description, i.e., as an issue of the psychology and philosophy of description. Elin will be working closely with Terry Winograd and Lucy Suchman. Dates of visit: June-December 1989. ANDRE SCEDROV, University of Pennsylvania. For the past several years, Andre has been working in Logical Foundations of Programming Structures, an area that bears on logic, theoretical computer science, and algebra and topology in mathematics. His most recent work in this area is concerned with incorporating inheritance and other features of object-oriented programming within type systems with static type-checking. He is now working on refinements of type systems that would express computational resource requirements as program specifications. In this setting the compliance of a program with the imposed resource bounds would be insured at compile-time. Dates of visit: July 1989-August 1990. HINRICH SCHUETZE, University of Stuttgart, Germany. Hinrich received a Master's degree in Computer Science from Stuttgart University in April 1989. His thesis deals with the treatment of plurals in natural-language processing systems. At this time, semantics -- especially the semantics of plurals -- is his main interest. While at CSLI, he will work on PROSIT (PROgramming in SItuation Theory), a new programming language that has many features of situation theory built in. He would like to extend PROSIT to a tool for the semantic processing of natural-language input. Dates of visit: July 1989-August 1990. HIDETOSI SIRAI, Associate Professor, Department of Psychology, Chukyo University, Japan. Hidetosi's background is in computer science. He has been working on Japanese Phrase-Structure Grammar (JPSG) and is interested in Situation Semantics (SS) to describe semantic phenomena in Japanese and English. During his stay at CSLI, he will work on JPSG + SS + ? = NLU (Natural-Language Understanding). Dates of visit: July 1989-February 1990. BARBARA TVERSKY, Department of Psychology, Stanford University. Barbara is on sabbatical this year. Dates of visit: AY 1989-90. WILLIAM UZGALIS, Assistant Professor of Philosophy , Oregon State University. Bill is interested in identity and individuation, personal identity, and the debate between essentialists and antiessentialists over such issues as the proper semantics for natural kind terms. He works on issues in the philosophies of Locke and Plato. Dates of visit: July 1988-August 1990. ------------------------------ End of NL-KR Digest *******************