clarke@utcsri.UUCP (Jim Clarke) (01/13/88)
(SF = Sandford Fleming Building, 10 King's College Road)
SUMMARY:
THEORY/SYSTEMS SEMINAR, Tuesday, January 19, 11 am, SF1105 -- R.D. Tennent:
"Towards a Language for Applicative AND Imperative Programming"
A.I. SEMINAR, Tuesday, January 19, 2 pm, SF1105 -- Anand S. Rao:
"Semantics of Dynamic Epistemic Systems"
SYSTEMS SEMINAR, Thursday, January 21, 11 am, SF1101 -- James R. Cordy:
"TuringTool: A Knowledge-Based User Interface
to Aid in the Software Maintenance Task"
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THEORY/SYSTEMS SEMINAR, Tuesday, January 19, 11 am, SF1105 **
Professor R.D. Tennent
Queen's University
"Towards a Language for Applicative
AND Imperative Programming"
Both the applicative and the imperative programming paradigms have signifi-
cant advantages. Is it possible for a language to support both of these
paradigms adequately, while also retaining the advantages of each of the
"pure" frameworks? Ideally, such a programming language would allow simple
reasoning about properties of both imperative and applicative aspects of
programs but also have simple and efficient implementations, and would pro-
vide the security and efficiency of statically-typed languages, but also
have the flexibility and syntactic succinctness of type-less languages.
No programming language in current use achieves these ambitious goals, but
over the last ten years there have been several important developments, and
this talk will attempt to justify my belief that these goals will soon be
achievable.
A.I. SEMINAR, Tuesday, January 19, 2 pm, SF1105
Dr. Anand S. Rao
IBM T.J. Watson Research Center
(On leave from U. of Sydney, Australia)
"Semantics of Dynamic Epistemic Systems"
In classical first-order logic the addition of a new axiom to a set of
axioms can never decrease the set of theorems. This property is often
called the Monotonicity property. Logics which lack this property are
called Nonmonotonic logics and have received a great deal of attention in
the AI community. Three of the most important such nonmonotonic logics
are Default Logic, Circumscription and Autoepistemic logic. All these
logics make some assumptions about the current world and `jump to con-
clusions' based on incomplete information.
An important aspect of nonmonotonicity, not addressed by the above logics,
is the dynamic process of Knowledge (or Belief) Revision. It is the pro-
cess by which an agent revises his existing knowledge in the light of
new(possibly contradictory) information from the external world. We pro-
vide a meta-theoretic, modal and axiomatic theory of the dynamic aspects
of such systems and show their equivalence. The axioms which we provide
for dynamic epistemic systems helps us to derive new knowledge based on
the old knowledge and the new information. Our work has far reaching
applications in the areas of Planning, Database Updates and Speech Act
Theory. We conclude the talk by taking a simple example from the
blocks-world and showing how our approach avoids the Frame Problem and
the Ramification Problem.
The main contribution of this work is in providing a model theory and
proof theory of dynamic systems. (This is a joint work with Norman Foo)
SYSTEMS SEMINAR, Thursday, January 21, 11 am, SF1101 **
Prof. James R. Cordy
Queen's University at Kingston
"TuringTool: A Knowledge-Based User Interface
to Aid in the Software Maintenance Task"
TuringTool is a programming environment specifically designed to support
the maintenance task. In order to avoid the cognitive overhead of simul-
taneously interpreting several different representations of the program as
a unit, TuringTool bases all of its views of the program on a single
comprehensive viewing paradigm: source text elision. This talk describes
how this paradigm can be used to represent several kinds of views appropri-
ate to the maintenance of large source programs, including structural views
and views based on knowledge of the maintenance task. The technique easily
extends to allow representation of complex programmer knowledge using sim-
ple set theoretic operators to combine the knowledge encoded in several
views into one.
Key words :
Programming environments, software maintenance, user interfaces,
knowledge-based systems, elision, programming languages, Turing.
** These two sections are part of our QUEEN'S WEEK. Professor S. Akl also
from Queens will be speaking at one of seminars later this term.
--
Jim Clarke -- Dept. of Computer Science, Univ. of Toronto, Canada M5S 1A4
(416) 978-4058
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