Meeting Agenda

Wednesday, June 12th, 1996

Location:: DC 1304
Time:: 1:30 PM
Chair:: Wilkin Chau

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:: June 19, 1996
Location:: DC 1304
Time:: 1:30 PM
Chair:: Bill Cowan
Technical presentation:: Leith Chan

4. Forthcoming

Chairs:

Matthew Davidchuk
Ed Dengler
Saar Friedman
Ryan Gunther

Tech Presenters:

Josh Cameron
Stewart Chao
Wilkin Chau
Bill Cowan

5. Technical Presentation

Presenter:: Richard Bartels
Title:: Hierarchical B-Spline Surface Fitting

Abstract:

A survery will be presented of the nature of a hierarchical B-spline and two uses of its properties for surface fitting. One use provides for the decomposition of the fitting problem into subproblems that concentrate on surface features. The other provides a regularization of such a fitting to permit subsequent, multi-level editing and animation.

6. General Discussion Items

7. Action List

University of Toronto visit

8. Director's Meeting

9. Seminars



DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES

PROGRAMMING LANGUAGES SEMINAR

                    -Wednesday, June 12, 1996

Gord Vreugdenhil, Dept. Comp. Sci., Univ. Waterloo will
speak  on  ``Abstract  Interpretation  as  a  Tool  for
Information Discovery''.

TIME:                3:30-4:30 p.m.

ROOM:                DC 1331

ABSTRACT

The  normal  goal  when  interpreting  a  program is to
perform  the  actions  required by the semantics of the
source  language.  Abstract interpretation replaces the
normal  semantics  with alternate semantics in order to
discover  information  regarding  some  aspect  of  the
source  program.  Such interpretations can be performed
even  when  only partial information is available about
the  inputs  to  the  program.   In  this  talk we will
briefly   review  the  basic  foundations  of  abstract
interpretation    and   then   discuss   a   particular
interpretive  algorithm that can be used as a framework
for   many  types  of  abstract  interpretations.   The
interpretive   algorithm   can  be  used  to  determine
``soft-type'' information and also forms the basis of a
class   of  program  transformation  techniques  called
``partial evaluation''.




DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES

MASTER'S THESIS PRESENTATION

                    - Thursday, June 13, 1996

Yanni Ellen Liu,  graduate  student,  Dept. Comp. Sci.,
Univ. Waterloo, will speak on "Performance Measurements
of Thread Packages in Support of Distributed Multimedia
Applications".

TIME:                1:30-2:30 p.m.

ROOM:                DC 1331

ABSTRACT

This  thesis addresses the operating system support for
multimedia  applications  in  distributed systems, with
the  emphasis  on  adapting  general-purpose  operating
systems  to support distributed multimedia applications
by multi-threading.

We  examine  the off-the-shelf thread packages, as well
as a thread package that was developed at University of
British  Columbia, called Real Time Threads (RTT). This
thread  package  was  implemented on UNIX, and has been
used    by    the    CITR   (Canadian   Institute   for
Telecommunications  Research)  Broadband Services major
project to provide supporting services in a distributed
news-on-demand application.

We  have  implemented  RTT  on  OS/2, a general-purpose
operating    system   for   personal   computers.   The
performance is analyzed by designing and implementing a
suite  of  measurement  tests. The results are analyzed
and  compared with the RTT implementation on UNIX. Many
issues   related   to  implementing  user-level  thread
packages,   evaluating   the   performance   of  thread
packages,  and  designing a real time kernel to support
distributed  multimedia applications are identified and
studied.



CS Colloquium Series
Computer Science Department
University of Waterloo

Type Polymorphism for Object-Oriented and Distributed Programming

By: 	Dominic Duggan
Of:	Department of Computer Science
	University of Waterloo

Date:	Tuesday,  June 18, 1996
Time:	4:00 P.M.
Place: 	Davis Center, Room 1304

Abstract:

The last ten years have seen exciting work on new type systems for 
programming languages.  One of the key new concepts is "type 
polymorphism," and its combination with subtyping and inheritance in 
object-oriented languages.  Type polymorphism is currently the main 
consideration for extending the Java language and virtual machine.

I will describe some of the work I am doing in type polymorphism.  
This work includes a new static type system for object-oriented 
languages with type polymorphism.  This is the only type system to 
provide objects with polymorphic methods.  I will also describe an 
approach I have developed to providing type-safe user-definable 
marshalling for distributed polymorphic languages.  The approach is 
based on run-time types in polymorphic languages.

The target implementation language for these extensions is a new 
distributed programming language, designed as an extension to Standard 
ML.  Time permitting, I will discuss other work in this new language 
(including implementation).

No prior knowledge is assumed of type polymorphism, marshalling, ML or 
even Java.  A minimal knowledge of objects, as in Modula-3 or C++, is 
assumed.

Biography

A native of Dublin, Ireland, Dr Duggan obtained his PhD from the 
University of Maryland, College Park.  His accent appears to have been 
a casualty of this experience.  His research interests are in 
programming languages, programming environments and software 
engineering.  His work has appeared in several journals.  His most 
recent focus has been in the design and implementation of 
object-oriented and distributed programming languages, and in 
programming-in-the-large.  

Everyone is welcome