From: calendar@ALMADEN.IBM.COM (IBM Almaden Research Center Calendar)
Newsgroups: ba.seminars
Subject: IBM ARC seminars 12 - 16 OCT 92
Date: 10 Oct 92 01:43:06 GMT


                     IBM Almaden Research Center
                           650 Harry Road
                       San Jose, CA 95120-6099

                              CALENDAR
                        October 12 - 16, 1992


10/12 - SOLVING SYSTEMS OF SET CONSTRAINTS
A. Aiken, Functional Programming, Computer Science

Comp. Sci. Sem.     Monday, October 12     3:00 p.m.     Room: Aud A

Set constraints are a simple formalism for expressing constraints
between sets of tree-structured terms.  A set constraint has the form "X
is a subset of Y," where the expressions X and Y are built from
variables, set operations (union, intersection, negation), and
constructors.  Because of their ability to describe recursive data
structures, set constraints are a natural tool for program analysis.
Set constraints are also closely related to tree automata.

In applications, the most interesting  problem is determining the
solutions of systems of set constraints.  In this self-contained talk,
we give an overview of the state of knowledge in this area, a survey of
the current applications of set constraints, and a brief description of
an implementation of a set constraint solver we have implemented.
Members of the audience will be encouraged to think about whether their
favorite analysis problems might be amenable to a set constraint
formulation; we are looking for new applications.
Host:  J. Williams


10/14 - FROM PROBLEM-DRIVEN LOGIC TO USE-DRIVEN LOGIC
S. Feferman, Stanford University

Comp. Sci. Sem.     Wednesday, October 14     11:00 a.m.    Room: G2-301

This is a repeat of a lecture given at a symposium held at the Ecole
Normale Superieure in Paris, April 6, under the general title "La
seconde vie de la logique mathematique" (The second life of mathematical
logic), which was curiously given the English subtitle:  "Is
mathematical logic alive." I argued that mathematical logic is not only
alive, it has not been near death, but that the impression of its
resuscitation from near death has been due to the surge of applications
of logic in theoretical computer science.  Without denying the
significance of these developments, I stressed:

1.  Pure, problem-driven logic is very much alive and continues to be
    pursued vigorously and unabatedly.

2.  Applied, use-driven logic has a long history in a variety of areas
    besides computer science: mathematics, philosophy, linguistics and
    even physical science and economics.

3.  The criteria for successful work in the two directions are very
    different, and require different frames of mind.

The talk concluded with a personal account of how I had been brought to
look at certain applications of work on the foundations of constructive
mathematics to theoretical computer science, and some views I have
developed in the process about promising directions of research as well
as misdirected efforts.
Host:  M. Vardi


10/15 - FULL DISTRIBUTION IN OBJECTIVITY/DB
A. E. Wade, Objectivity Inc.

Comp. Sci. Sem.     Thursday, October 15     10:00 a.m.     Room: Aud A

Objectivity/DB has delivered to production use a fully distributed
object DBMS architecture, where full distribution includes distribution
of data and control, as described here.  Distribution of data allows
objects to reside and execute anywhere on the network, and to be used
anywhere on the network, transparently, by users and applications that
need not be aware of the object's actual location, and without any
server bottlenecks.  This includes any mixture of heterogeneous
platforms and operating systems (from among those currently supported),
with creation, use, sharing, and storage of objects on any platform and
environment, regardless of byte ordering, floating point formatting,
data alignment, etc. Distribution of control allows users and
applications to access multiple databases in a federated database.  Each
database is under separate administrative control, with its owner
deciding when to shut it down, control access, etc., yet all database
services are transparently available across databases, including
inter-object associations, transactions, composite objects with
propagating methods spanning databases, etc.  This allows any mapping of
personal, group, departmental, and enterprise databases, or design,
test, manufacturing databases, etc.  All of this is supported by an
architecture of object manager, storage manager, and network manager
that uses intelligent clustering, multiple levels of caching, and direct
in-memory pointer swizzling to achieve speeds comparable to native
in-memory pointer chasing for second traversals, yet scale with
approximately constant objects/second performance into the
multi-terabyte range, as currently measured in customer applications
into the gigabyte-plus range.
Host:  T. Lehman


10/15 - MAIN CHAIN LIQUID CRYSTALLINE POLYMERS AND MODEL COMPOUNDS FROM
2,2'-DISUBSTITUTED BIPHENYLS
C. P. Jariwala, Dept. of Polymer Science, Univ. of Southern Mississipi

Poly. Sci. & Tech. Sem.  Thursday, October 15  11:00 a.m.  Room: E2-450

A series of model compounds from biphenyls substituted in the 2 and
2'-positions were synthesized with various terminal flexible chain
lengths (n=1-10) connecting the biphenyl nucleus to the mesogenic cores.
The analogous polymers with spacers of 7-10 methylene units have been
synthesized and characterized.  This substitution in the 2,2'-positions
causes steric hindrance forcing the phenyl rings to twist and be
non-coplanar to each other.  Additionally, it would result in a wide and
angular group in the center and destroy the rod-like shape of the
molecule and therefore not expected to show liquid crystalline behavior.
It was our interest to study the effect of this new substitution pattern
on the mesomorphic behavior of polymers and model compounds.  In the
model compounds higher homologous have both a smectic and nematic phase
while the lower homologous are nematic only.  Soluble, high molecular
weight polymers were obtained in good yields.  All the polymers show
enantiotropic mesophases.
Host:  R. Twieg


10/15 - SYNTHESIS, CHARACTERIZATION AND PHOTOPOLYMERIZATION OF NOVEL
FLUOROALKYL SUBSTITUTED METHACRYLATES
C. P. Jariwala, Dept. of Polymer Science, University of Southern
Mississippi

Poly. Sci. & Tech. Sem.   Thursday, October 15  11:00 a.m.  Room: E2-450

A new synthetic approach to substituted methacrylates which uses the key
intermediate ethyl a-(cholormethyl) acrylate (ECMA) involves
substituting with various fluoroalchols at the highly reactive allyl
chloride group.  High yields and ready purification makes available a
variety of ether derivatives.  Rapid, high conversion polymerization of
these acrylates was carried out neat with ABIN at 50-70 degree C.
Monomer and polymer structures were confirmed by FTIR, and both solution
and solid state (1)(3)C NMR spectroscopy.  Some of the monomers form
highly ordered liquid crystalline phases.  Polymerization kinetics of
the monomers using laser and mercury UV lamp initiation as a function of
substituent size and mesophase verses the isotropic phase was also
studied.  The polymerization rate and conversion with comparable quanta
are much higher in the smectic phase than in the isotropic phase due to
decrease in termination in this highly ordered mesophase.  Pulsed laser
photopolymerization in the mesophase continued even after the laser
pulse was turned off.  Long radical life times (>hours) were confirmed
by electron spin resonance spectroscopy.
Host:  R. Twieg


10/15 - EXACT CRITICAL THEORY FOR THE TWO-IMPURITY KONDO PROBLEM
I. Affleck, University of British Columbia

Phys. Sci. Sem.     Thursday, October 15      2:30 p.m.     Room: J2-609

A new renormalization group approach to quantum impurity problems, based
on conformal field theory, will be introduced.  The two-impurity Kondo
problem has two stable phases with, respectively, inter-impurity singlet
formation or Kondo screening.  In the presence of particle- hole
symmetry, these two phases are separated by a non- fermi-liquid critical
point.  All critical properties of this fixed point can be derived
exactly using the new approach.
Host:  B. Jones


10/16 - EXOTIC QUANTUM EFFECTS IN QUASI-ONE DIMENSIONAL ANTIFERROMAGNETS
I. Affleck, Department of Physics, University of British Columbia

Phys. Sci. Colloq.     Friday, October 16    10:30 a.m.    Room: Aud. A

Quantum fluctuations can disorder the groundstates of
quasi-one-dimensional antiferromagnets.  This leads to a wealth of
exotic low-energy behavior including a fundamental difference between
materials containing integer and half-odd-integer spins, the Haldane
gap.  Recent theoretical results and experiments on Ni(C2H8N2)2NO2' ClO4
(NENP) will be reviewed.
Host:  S. Zhang

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For further information on individual talks, please contact the host
listed above.

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