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NL-KR Digest Volume 01 No. 14
NL-KR Digest (10/10/86 10:15:24) Volume 1 Number 14
Today's Topics:
Tiny ATN's
Seminars:
Generic Tasks in Knowledge-Based Reasoning
Planning Simultaneous Actions in Temporally Rich Worlds
From CSLI Calendar, Categorical Unification Grammar
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Date: Thu, 9 Oct 86 16:38 EDT
From: Peter Benson <dcdwest!benson@sdcsvax.ucsd.edu>
Subject: Tiny ATN's
I would like to teach a small group of people about ATN's. These
people don't know Lisp. I wonder if someone has a small ATN
parser written in Pascal, Algol, C or some similar language that
they would be will to share?
_
Peter Benson | ITT Defense Communications Division
(619)578-3080 | 10060 Carroll Canyon Road
decvax!ittvax!dcdwest!benson | San Diego, CA 92131
ucbvax!sdcsvax!dcdwest!benson |
dcdwest!benson@SDCSVAX.EDU |
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Date: Tue, 30 Sep 86 20:39 EDT
From: DEJONG%OZ.AI.MIT.EDU@MC.LCS.MIT
Subject: Generic Tasks in Knowledge-Based Reasoning
[Excerpted from IRList]
Wednesday, 1 October 3:00pm Room: NE43-512A
Generic Tasks in Knowledge-Based Reasoning: Caracterizing and
Designing Expert Systems at the "Right" Level of Abstraction
B. Chandrasekaran
Laboratory for Artificial Intelligence Research
Department of Computer and Information Science
Ohio State University
Columbus, Ohio 43210
We outline the elements of a framework for expert system design that
we have been developing in our research group over the last several
years. This framework is based on the claim that complex
knowledge-based reasoning tasks can often be decomposed into a number
of generic tasks each with associated types of knowledge and family
of control regimes. At different stages in reasoning, the system will
typically engage in one of the tasks, depending upon the knowledge
available and the state of problem solving. The advantages of this
point of view are manifold: (i) Since typically the generic tasks
are at a much higher level of abstraction than those associated with
first generation expert system languages, knowledge can be acquired
and represented directly at the level appropriate to the information
processing task. (ii) Since each of the generic task has an
appropriate control regime, problem solving behavior may be more
perspicuously encoded. (ii) Because of a richer generic vocabulary in
terms of which knowledge and control are represented, explanation of
problem solving behavior is also more perspicuous. We briefly
describe six generic task that we have found very useful in our work
on knowledge-based reasoning: classification, state abstraction,
knowledge-directed retrieval, object synthesis by plan selection and
refinement, hypothesis matching, and assembly of compound hypotheses
for abduction.
++++++++++++++++++++++++++++++++++++++++++
Date: Friday, 26 September 1986 11:09-EDT
Subject: LCS Distinguished Lecturer Series
Thursday, 2 October 3:30pm Room: 34-101
Pattern Knowledge and Search: The Suprem Architecture
Hans J. Berliner
Senior Research Scientist
Computer Science Department
Cartnegie Mellon University
We describe a problem solving architecture that combines rapid search
through a state space coupled with highly sophisticated evaluation of
states. Speed of searching is made possible by special purpose
hardware tailored to producing state-change operators for the domain.
Evaluation of states is done by more general machines that can extract
small patterns in parallel and use these to produce much better
evaluations than are possible in non-pattern oriented methods. In
this connection, we present a hierarchy of knowledge.
This method has been applied to the development of Hitech, a chess
machine that is now ranked within the top 200 chess players in the US.
While Hitech's chess understanding is still far short of that of the
very top players in the world, its ability to calculate accurately,
and look at one million times as many possibilities in unit time as
the best humans can, make up for this to a large degree. We discuss
the issues involved in creating such architectures and how they can be
improved. Performance data on Hitech will also be presented.
Host: Michael L. Dertouzos
------------------------------
Date: Thu, 2 Oct 86 13:30 EDT
From: Brad Goodman <BGOODMAN@BBNG.ARPA>
Subject: Planning Simultaneous Actions in Temporally Rich Worlds
[Excerpted from AIList]
Monday, 6 October 10:30am Room: 3rd floor large conference room,
BBN Labs, 10 Moulton Street, Cambridge
BBN Laboratories
Science Development Program
AI/Education Seminar
Planning Simultaneous Actions in Temporally Rich Worlds
Professor James Allen
University of Rochester
(james@rochester)
This talk describes work done with Richard Pelavin over the last few
years. We have developed a formal logic of action that allows us to
represent knowledge and reason about the interactions between events
that occur simultaneously or overlap in time. This includes interactions
between two (or more) actions that a single agent might perform
simultaneously, as well as interactions between an agent's actions and
events occuring in the external world. The logic is built upon an
interval-based temporal logic extended with modal operators similar to
temporal necessity and a counterfactual operator. Using this formalism,
we can represent a wide range of possible ways in which actions may
interact.
------------------------------
Date: Wed, 8 Oct 86 20:43 EDT
From: Emma Pease <Emma@CSLI.STANFORD.EDU>
Subject: From CSLI Calendar, October 9, No. 2
[Excerpted from CSLI Calendar]
CSLI Seminar
Categorial Unification Grammar
Lauri Karttunen and Hans Uszkoreit
October 16, 1986
The introduction of unification formalism and new types of rules has
brought about a revival of categorial grammar (CG) as a theory of
natural language syntax. We will survey some of the recent work in
this framework and discuss the relationship of lexical vs. rule-based
theories of syntax.
Non-transformational syntactic theories traditionally come in two
varieties. Context-free phrase structure grammar (PSG) consists of a
very simple lexicon and a separate body of syntactic rules that
express the constraints under which phrases can be composed to form
larger phrases. Classical CG encodes the combinatorial principles
directly in the lexicon and, consequently, needs no separate component
of syntactic rules.
Because a unification-based grammar formalism makes it easy to
encode syntactic information in the lexicon, theories such as LFG and
HPSG, which use feature sets to augment phrase structure rules, can
easily encode syntactic information in the lexicon. Thus syntactic
rules can become simpler and fewer rules are needed. In this respect,
HPSG, for example, is much closer to classical CG than classical PSG.
Pure categorial grammars can also be expressed in the same
unification-based formalism that is now being used for LFG and HPSG.
This includes more complex versions of CG employing the concepts of
functional composition and type raising as they are currently
exploited in the grammars of Steedman, Dowty, and others. The merger
of strategies from categorial grammar and unification grammars
actually resolves some of the known shortcomings of traditional CG
systems and leads to a syntactically more sophisticated grammar model.
--------------
READING AND DISCUSSION GROUP ON FIGURAL REPRESENTATION
Organizers: David Levy, Geoff Nunberg
First meeting: Thursday, October 9 at 10 AM, Ventura Hall
We are forming a reading and discussion group to explore the nature of
figural (roughly speaking, visual) representation. Systems of figural
representation include writing systems, systems of musical notation,
screen "icons," bar graphs, architectural renderings, maps, and so
forth. This topic lies at the intersection of various concerns
relevant to a number of us at CSLI, at Xerox PARC, and at SRI---
theoretical concerns about the nature of language and representation
and their manifestation in the building of systems and the design of
visual notations for formal languages. There is currently no
well-motivated framework for discussing such material, no map on which
to locate important terms such as "document," "text," "icon," and
"format." But there is clearly a coherent subject matter here waiting
to be explored.
Topics we want to look at in early meetings include:
1. Properties of the figural.
2. Figural representation and representation in general.
3. The typology of figural systems.
4. Writing as a figural representation system; distinctive
properties of written language.
5. The technological basis for figural representation (from
writing to print to the computer).
Initially, we plan to organize the discussion around readings drawn
from the literatures of a number of disciplines, among them
linguistics, psychology, literary theory, art criticism, AI,
anthropology and history. We expect to meet once a week (or once
every two weeks) at Ventura Hall (CSLI), starting Thursday morning,
October 9, at 10AM. Please note that we consider this to be a working
group, not a general public forum or a TINLunch.
At our first meeting, we will be discussing a short paper, "Visible
Language," which outlines some of the areas we will be concerned with.
Copies are available at the Ventura Hall desk.
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End of NL-KR Digest
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