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AIList Digest Volume 6 Issue 011
AIList Digest Monday, 18 Jan 1988 Volume 6 : Issue 11
Today's Topics:
Seminars - Rational Choice and Cognitive Illusion (HP) &
Cooperative Inference Machine: CHI (SRI) &
OBJ as a Theorem Prover (SRI) &
Four-Valued Semantics for Terminological Logics (AT&T)
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Date: Mon 11 Jan 88 09:38:06-PST
From: Oscar Firschein <FIRSCHEIN@IU.AI.SRI.COM>
Subject: Seminar - Rational Choice and Cognitive Illusion (HP)
HP Labs Colloquium: Prof. Amos Tversky
Subject: Rational Choice and Cognitive Illusion
The analysis of decision and judgment under uncertainty reveals
pervasive and systematic departures from the rational theory of
judgment and choice. In particular, people exhibit overconfidence in
action and belief, susceptability to framing effects, and
inconsistent attitudes toward risk. These pheenomena are traced to
the operation of a limited number of heuristic principles, which are
generally useful but often produce illusion and bias.
Time: 4 P.M. Thursday, Feb. 4, 1988
Place: Hewlett-Packard
5M Auditorium
1501 Page Mill Road, Palo Alto
Non-HP employees: Welcome! Please come to the lobby on time
so that you may be escorted to the 5M auditorium
Refreshment: A wine and cheese reception will follow.
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Date: Thu, 14 Jan 88 10:05:24 PST
From: seminars@csl.sri.com (contact lunt@csl.sri.com)
Subject: Seminar - Cooperative Inference Machine: CHI (SRI)
SRI COMPUTER SCIENCE LAB SEMINAR ANNOUNCEMENT:
A Cooperative High-Performance Sequential Inference Machine: CHI
Akihiko Konagaya
Computer Systems Research Laboratory
NEC Corporation, Japan
Tuesday, January 26 at 11:00 am
SRI International, Conference Room B, Building A
This talk will describe the design principles and new compiler
technique of CHI-II, a deskside backend inference machine, which
has been developed as part of the Fifth Generation Computer System (FGCS)
Project in Japan. CHI-II achieves 500 KLIPS for deterministic append
program execution by means of specialized hardware and machine code
optimization techniques. The architecture also executes interpretive
predicates efficiently. The merit of the micro-programmable "Wide Spectrum
Instruction Set," as opposed to the "Reduced Instruction Set (RISC),"
in terms of logic programming language execution, will be addressed.
One of the most important features of the CHI-II hardware is its large capacity
main memory (600MBytes) for a single user. Cutting-edge memory device
technology makes it possible to develop a large-capacity, but small-size,
main memory system comparable to an ordinal secondary storage. This
large-capacity memory allows us to store massive amounts of data, such as
the knowledge base of an expert system, in memory,
and greatly contributes to achieving high performance in large-scale
application systems by eliminating the overhead of virtual memory
management.
The CHI software system aims at integrating heterogeneous programming
environments on a workstation in a distributed operating system fashion. The
software enables CHI to act like a stand-alone computer without
input/output devices, rather than as an accelerator of a host machine. An
object-oriented means of intermachine communication, called "virtual objects,"
greatly simplifies the realization of bus-transparent input/output
operations, such as a remote file system and a remote window system. The
multiple process facility, although rather conservative, enables us
to develop practical system programs dedicated to logic programming. It
is also expected to be used as a good vehicle in which to study parallel logic
programming.
NOTE FOR VISITORS TO SRI:
Please arrive at least 10 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 Ave) 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: Visitors from Communist Bloc countries should make the
necessary arrangements with Fran Leonard, SRI Security Office,
(415) 859-4124, as soon as possible.
------------------------------
Date: Thu, 14 Jan 88 10:04:42 PST
From: seminars@csl.sri.com (contact lunt@csl.sri.com)
Subject: Seminar - OBJ as a Theorem Prover (SRI)
SRI COMPUTER SCIENCE LAB SEMINAR ANNOUNCEMENT:
OBJ AS A THEOREM PROVER
Joseph A. Goguen
Computer Science Laboratory
SRI International
Monday, January 25 at 4:00 pm
SRI International, Conference Room B, Building A
This talk has two goals: to introduce OBJ, and to present some techniques for
using OBJ as a theorem prover. OBJ is a wide-spectrum, first order functional
programming language rigorously based on *order-sorted* equational logic,
which provides a notion of *subtype* to support overloading, coercion,
multiple inheritance, and exception handling. This rigorous semantic basis
allows both a declarative programming style, and the direct use of OBJ for
theorem proving.
Parameterized programming is a powerful technique for software design,
production, reuse and maintenance, involving abstraction through two kinds of
module: *objects* to encapsulate executable code, and in particular to define
abstract data types; and *theories* to specify both syntactic and semantic
structure of modules. Each kind of module can be parameterized, where actual
parameters are modules. Modules can also import other modules, yielding
hierarchies of parameterized modules. Interfaces of parameterized modules are
defined by theories. For parameter instantiation, a *view* binds the formal
entities in an interface theory to actual entities in a module, and also
asserts satisfaction of the theory by the module. Views are first class
citizens that can be named, can import modules, and can even be parameterized.
*Module expressions* allow complex instantiations and may include commands
that transform already defined modules.
Typical higher order programming examples can be captured with just first
order functions, by the systematic use of parameterized programming. Some
examples are given, including a hardware verification example. New results
include a simple but useful extension of first order equational logic to allow
quantification over arbitrary function symbols, a perhaps surprising technique
for proving such equations using only ground term reduction, and some general
induction principles. All this provides a very powerful first order calculus
for reasoning about (first order)
functions.
NOTE FOR VISITORS TO SRI:
Please arrive at least 10 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 Ave) 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: Visitors from Communist Bloc countries should make the
necessary arrangements with Fran Leonard, SRI Security Office,
(415) 859-4124, as soon as possible.
------------------------------
Date: Fri, 15 Jan 08:45:27 1988
From: dlm%research.att.com@RELAY.CS.NET
Subject: Seminar - Four-Valued Semantics for Terminological Logics
(AT&T)
Title: A Four-Valued Semantics for Terminological Logics
Speaker: Peter F. Patel-Schneider
Schlumberger Palo Alto Research
3340 Hillview Ave.
Palo Alto, California 94304
Date: Monday, January 18, 1988
Time: 10:30 AM
Place: AT&T Bell Laboratories - Murray Hill 3D-473
Terminological logics formalize and extend the notions of concepts,
roles, and restrictions present in semantic networks, frame-based
systems, and object-oriented programming systems. The most important
semantic relationship in these logics is subsumption-whether one
concept is more general than another. Subsumption is a non-trivial
relationship and if the terminological logic is expressively powerful,
then determining whether one concept subsumes another is
computationally intractable. Because of this intractability,
knowledge representation systems based on terminological logics are
not suitable for use in knowledge-based systems.
This problem can be solved by using a four-valued semantics, resulting
in an expressively powerful terminological logic which has tractable
subsumption. The subsumptions supported by the logic are a type of
"structural" subsumption, where each structural component of one
concept must have an analogue in the other concept. Structural
subsumption captures an important set of subsumptions, similar to the
subsumptions computed in KL-ONE and NIKL. The four-valued semantics
can thus be used to develop object-based knowledge representation
systems suitable for use in knowledge-based systems.
Sponsor: Ron Brachman
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End of AIList Digest
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