CGL Meeting Minutes

Wednesday, April 10, 1996


Location:
DC1304
Time:
12:30 PM
Chair:
Dan Milgram

1. Adoption of the Agenda - additions or deletions

2. Coffee Hour

Coffee hour this week:
Any volunteers?
Coffee hour next week:
Any volunteers?

3. Next meeting

Date:
April 17, 1996
Location:
DC 1304
Time:
12:30 PM
Chair:
Thomas Pflaum
Technical presentation:
Michael McCool

4. Forthcoming

Chairs:
  1. Randall Reid
  2. Navid Sadikali
  3. Balasingham Balakumaran
Tech Presenters:
  1. Dan Milgram
  2. Thomas Pflaum
  3. Randall Reid

5. Technical Presentation

Presenter:
Steve Mann
Title:
Coordinate Free Geometry
Abstract:
In this talk, I motivate the use of a geometry abstract data type to allow for coordinate free calculations and to avoid common problems that occur when linear algebra is used for geometric calculations.

6. General Discussion Items

7. Action List

8. Director's Meeting

9. Seminars

COMPUTER SCIENCE SEMINAR

                    -Thursday, April 11, 1996

Tuomas  Sandholm, Dept. Comp. Sci., Univ. Massachusetts
at    Amherst,   will speak   on   ``Negotiation   among
Computationally Limited Self-Interested Agents''.

TIME:                11:00 a.m.- 12:00 p.m.

ROOM:                DC 1302

ABSTRACT

In   multiagent   systems,  computational  agents  make
contracts on behalf of the real world parties that they
represent.  The  significance of such systems is likely
to   increase   due  to  the  developing  communication
infrastructure,  the advent of electronic commerce, and
the  industrial  trend  toward outsourcing. My research
normatively  analyses  such  negotiations  among agents
that  try  to  maximize  payoff without concern for the
global  good.  The  most advanced normative theoretical
tools  available  are  game theoretic. However, in game
theory  full  rationality  of  the  agents  is  usually
assumed.  My work extends these normative approaches to
settings  in  which  computational limitations restrict
each    agent's   rationality   because   combinatorial
complexity  precludes  enumerating  and  evaluating all
possible outcomes.

Within   the   subfield  of  automated  contracting,  I
extended  the  contract  net  framework  to  work among
self-interested   agents.  The  original  contract  net
lacked  a  formal model for making bidding and awarding
decisions,  while in my TRACONET system these decisions
are based on marginal cost calculations. I developed an
iterative  scheme  for  anytime task reallocation where
agents  pay  each other for handling tasks. I uncovered
and  solved  problems  regarding  contracting while old
bids  are  pending.  I  constructed  three new contract
operators  and  proved  that  they  are  necessary  and
sufficient   for   reaching  a  globally  optimal  task
allocation  in  a  finite  number  of contracts. I also
proved  that  a leveled commitment contracting protocol
enables  contracts  that  are  impossible via classical
full commitment contracts. In addition, it enhances the
efficiency  of contracts when full commitment contracts
are possible. Finally, I identified and solved problems
of   distributed  asynchronous  implementation.
Within  coalition  formation,  I  developed a normative
theory     that     states     which    self-interested
computationally  limited  agents should form coalitions
and   which  coalition  structures  are  stable.  These
prescriptions depend on the performance profiles of the
agents'   problem   solving   algorithms,   and  differ
significantly  from those for fully rational agents. My
theory   includes  an  application  independent  domain
classification   with   bounded  rational  agents,  and
relates  it  to  two traditional domain classifications
with fully rational agents.

Within  contract execution, unenforced exchange methods
are   desirable   among  computational  agents  because
litigation  is  difficult.  I  developed  such a method
based  on  splitting  the exchange into chunks that are
delivered  one  at  a  time.  I  developed two chunking
algorithms  as  well as a nontrivial sound and complete
quadratic  chunk  sequencing  algorithm. I also derived
the  optimal  stable  strategies  for  carrying out the
exchange. Finally, I analyzed the role of real-time and
developed  deadline  methods  that  do  not  themselves
require enforcement.

I  evaluated  these  domain  independent  methods on an
NP-complete  distributed  vehicle  routing problem with
large-scale  instances  collected  from five real-world
dispatch  centers.  My  methods resulted in significant
transportation  cost  savings  on  this  problem  where
classical  game  theoretic  techniques are inapplicable
due to intractability.



                   The University of Waterloo
                      200 University Avenue
                        Waterloo, Ontario


        The Institute for Computer Research (ICR) and the 
             Department of Systems Design Engineering

                   Present a Joint Seminar on

      "Mining Predictive Patterns from Data:  Rough Sets Approach"


by:     Dr. Wojciech Ziarko

Abstract:

Data mining is considered to be  one of the most promising direc-
tions  spanning  database and AI research.  The primary objective
of database mining methodologies and systems is to help the  user
in  discovering  potentially  significant  facts or data patterns
which are frequently "buried" in the masses of irrelevant  infor-
mation.   The  patterns  of  particular interest are associations
between fields in multidimensional data collections.  The associ-
ations,  once  discovered, assume the form of empirical decision,
or prediction rules in the form IF  
THEN  with the probability P.  The rules can be used to
model the development of a complex process, e.g. the reaction  of
a stock market to changing external conditions or the reaction of
a biological system to changes in  the  environment.   The  rules
derived  from data can also be used to control complex processes.
Pattern classification is yet another  important  application  of
the  rules.  Other data mining problems are analysis of dependen-
cies between variables in multidimensional data  and  identifica-
tion   of   fundamental   factors  affecting  such  dependencies.
Although statistical methods offer some  help  in  that  respect,
their  applicability  is  limited by often strong assumptions and
general lack of techniques to analyze and characterize the struc-
tural relationships existing in data.  The analytical methodology
used for data mining presented in  this  talk  is  based  on  the
mathematical theory of rough sets.  In the rough sets approach no
assumptions are made about the statistical nature  of  the  data.
The  review of rough set-based approach to database mining is the
main subject of  this  presentation.  The  presentation  will  be
developed  around  an  extension  of  the rough set model, called
variable precision rough sets model.  Practical examples computed
with  our  systems Dataquest, Datalogic and KDD-R will be used to
illustrate the talk.  The talk is  directed  to  all  individuals
working  with data and interested in constructing models from the
data.



            The Institute for Computer Research (ICR) and 
            the Department of Systems Design Engineering


                   Present a Joint Seminar on

               "Learning to Recognize 3-D Objects"

by:     Dr. David G. Lowe

of:     Department of Computer Science
        University of British Columbia
        Vancouver, British Columbia

Abstract:

Many potential applications of computer vision  depend  upon  the
ability  to recognize objects and track their location over time.
Existing methods for matching 3-D object models  to  images  have
been quite successful for small numbers of rigid objects, but fu-
ture improvements in visual recognition will require methods  for
automatically  learning  models  of appearance from images.  This
talk will provide an overview of several ways in which  statisti-
cal  learning  methods can improve the reliability and efficiency
of visual recognition.  A new learning  method  called  Variable-
kernel   Similarity   Metric   (VSM)  learning  will  be  briefly
described.

Date:   Friday, April 19, 1996
Time:   3:30 p.m.
Place:  William G. Davis Computer Research Centre, Room 1302




10. Lab Cleanup (until 1:30 or 5 minutes)