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Focus 1992

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Array Vol. 3, No. 1
Spring 1992
CICSR welcomes seven
talented new researchers
with very diverse interests
■ The research interests of the new crop of
CICSR faculty members profiled in this
issue defy categorization. They range from
walking robots to automated fish processing, with geometric problems, electromagnetic theory, computer logic, medical
imaging and VLSI chip design in between.
Some of the researchers are interested in
applied research, while others focus on
One thing you can generalize about,
however, is the skill and aptitude of the
researchers themselves. They are young,
... continued on page 2
The seven newest CICSR members, from left,
back row: Jack Snoeyink, Matthew Palmer,
Hussein Alnuweiri; front row: Dinesh Pai, Ray
Gosine and Craig Boutilier.
Palmer improving
medical imaging
page 2
Shapes of all kinds
page 3
Computer logic theory
page 4
Machines that move
page 5
Industrial automation:
a practical perspective
page 6
Parallel computing and
electromagnetic theory
page 7 NEW RECRUITS  ... continued from cover
talented and enthusiastic new members of
the UBC faculty.
These seven people have come to UBC in
the past year from various parts of the
world, as far afield as India, England and
Saudi Arabia. They have training at the
world's finest academic institutions,
including Cambridge, Stanford and M.I.T.
Many of the new faculty members are
already working on collaborative projects
with other CICSR members; others plan to
do so in the near future. In general, they
commend the goals of CICSR and are
looking forward to meeting and working
with more CICSR members. We decided
to get the ball rolling by introducing
CICSR Focus readers to all of the new
faculty members and their work in this
Improving medical imaging
Director's Statement
Over the last five years, membership in CICSR has doubled from 30
to 60. Most of this increase is due to
the intensive faculty recruiting
efforts of the three constituent UBC
departments: Computer Science,
Electrical Engineering, and Mechanical Engineering. This recruiting has been remarkably successful.
These recruits are young (under 35 in
most cases), talented, and come from
diverse backgrounds. Four have
recently been recommended for
fellowships with the Advanced
Systems Institute of B.C.
We thought it would be. interesting to
profile some of the newest of our new
recruits, and in this issue of the
newsletter, we will focus on seven
who have been hired over the past
year — three in Computer Science,
three in Electrical Engineering and
one in Mechanical Engineering. ■
■ Improving the quality and precision of
medical imaging is the main research
interest of Matthew Palmer, a new
member of the Department of Electrical
UBC is an excellent place to pursue his
research — he is working with UBC
hospital researchers and has also used the
positron emission tomograph (PET)
facilities at TRIUMF. Palmer's work is
multidisciplinary, involving basic physics,
image processing and engineering.
Palmer is now working in conjunction
with UBC hospital staff to use magnetic
resonance imaging (MRI) to study
multiple sclerosis. "The project has raised
questions on how we handle and process
images using the computer," said Palmer.
One question he would like to answer is:
What sort of image-based measurements
can you achieve and what effects them?
Precise measurements are not crucial for
diagnosis of patients, which is usually
done visually, but are important for
medical researchers. Palmer says that
using MRI, a very safe form of medical
imaging, researchers can do as many scans
as they want and look for changes in the
brain almost hourly. However, to get
meaningful results from this data, they
need precise measurements of location of
lesions, areas of coverage, distribution
within the brain and changes over time.
Palmer is working on various aspects of
this problem, from image-based measurements to hardware development to hold
the patient's head in the right place.
Palmer is also at work on a very different
research project: the study of focus waves.
These waves, discovered in the past ten
years, provide novel solutions to 150-
year-old wave equations. Some of these
solutions have the ability to propagate
over very large distances without losing
their focus.
Although the research is at a very early
stage, Palmer thinks it may be possible to
incorporate these waves into better probes
for medical scanning. "They produce a
different type of beam that could be useful
in ultrasound imaging and possibly in
ultrasound tomography," said Palmer.
Palmer and a colleague have simulated
focus waves on the computer, but haven't
yet figured out a practical way to physically generate these waves. Generation of
focus waves would take a tremendous
amount of equipment, and because they're
so new, nobody knows how to control
them or generate them properly, said
He plans to continue refining computer
generation of focus waves, breaking them
into physically realizable elements. It is
possible, in theory, to generate waves that
propagate forever without losing their
focus, but this would require an infinitely
large transmitter. However, if Palmer's
scaled-down focus waves look promising
in simulation, he plans to build a device to
generate them.
"It could be a new kind of ultrasound
probe, but that's getting far ahead of where
we are now," said Palmer. ■
Matthew Palmer
Palmer is now working in
conjunction with UBC hospital
staff to use magnetic resonance
imaging (MRI) to study multiple
sclerosis. The project has raised
questions about how we handle
and process images using
computers. Jack Snoeyink
"Lots of two-dimensional
objects are easy to understand
— you can separate any
problem into two problems.
Three-D is much more
difficult. But we live in three
dimensions, so I'd like to try
and understand it."
Shapes of all kinds interest Snoeyink
■ Jack Snoeyink's main research interest
is in using the computer to solve geometry
problems, or problems best stated geometrically. He is studying the design and
analysis of algorithms of geometric
computation and its application to problems arising in solid modelling, CAD/
CAM, computer graphics, data structuring
and robotics, as well as to discrete geometry and topology.
To simplify, Snoeyink is interested in
shapes of all kinds. He is a visual thinker,
and doesn't describe anything without
drawing a picture of it. He loves geometric
puzzles — complicated structures you can
take apart and put together again if you
have the skill and patience — the more
complicated the better.
Snoeyink is interested in three-dimensional
objects, and most of his research projects
involve 3-D. "Lots of two-dimensional
objects are easy to understand — you can
separate any problem into two problems.
Three-D is much more difficult. But we
live in three dimensions, so I'd like to try
and understand it. I'm a theoretician," said
One of the projects Snoeyink is currently
working on is the development of efficient
algorithms to overcome cartographers' line
simplification problem. When map-makers
receive digitized data from actual photographs, there is far too much data to
display clearly, so many of the coordinates
have to be discarded. Cartographers
currently throw away point arbitrarily and
then look for best-fit curves. This arbitrary
process is slower and less accurate than it
could be.
Snoeyink's approach to the problem is
quite different. He enlarges the points so
that simpler lines can be drawn through
them, with much fewer segments. "I don't
pay the cost of finding the absolute best,
but I can guarantee the resulting shape
beforehand," said Snoeyink. "It's better
than arbitrarily throwing away points."
Snoeyink is also working on the analysis
and decomposition of non-convex objects,
which are among the most difficult three-
dimensional objects to analyze. For CAD
systems to incorporate such objects, and to
analyze their structural properties, these
objects must be broken up into convex
pieces. Snoeyink is working on an
algorithms to cut polyhedrons into the
fewest number of convex pieces possible
and analyze the resulting shapes. He spent
summer at the Ricoh Software Research
Centre in Tokyo working on this problem.
CAD programs make complex objects
by combining many simpler objects. A lot
of work needs to be done on boundary
representation, which is different than the
representation of the collection of 3-D
objects. Snoeyink has developed an
algorithm to represent any arbitrary
polygon as a formula using unions and
intersection where the basic shapes
(primitives) are unions defined by the
edges. The work will make CAD conversions from boundary representations more
efficient and faster. "There are a lot of
brute-force ways of doing the same thing,
but they are much more complicated than
Snoeyink majored in both computer
science and mathematics as an undergraduate and his work now combines the
two disciplines. "Doing geometry
problems using computers gives you a
whole new set of questions to ask about
the mathematics. You can see the
applications of mathematics as pictures
on the screen. When you put the two
together, you get a chance to say new
things." ■ Boutilier takes a new look
at computer logic theory
In the course of our lives, we pick up
vast stores of knowledge about the world
around us, and much of it, we take for
granted. In Craig Boutilier's research, he
can take nothing for granted.
Boutilier, a new member of the Department of Computer Science, is interested
in supplying computers with logical
representations of the knowledge they
need to behave intelligently. It's a vast
and complex problem which draws on his
expertise in both logic and computer
"The computer has no background
knowledge, no evolution and no experience," said Boutilier. "On the other hand,
we carry with us so much context and
presupposition about the way the world
works. For example, we know that objects
stay where they are. You'd never think of
telling your computer that when it leaves
the room, the desk and the chair will stay
It's impossible to impart all the knowledge
people have into a computer, so the AI
community is currently addressing just
how much information a computer needs
to behave intelligently. This information
can't be presented in a black-and-white
fashion if a machine is to emulate human
intelligence. People regularly make
assumptions, jump to conclusions, forget
unimportant information and change their
minds about what they believe. People are
Craig Boutilier
It's impossible to impart all the knowledge people have into a
computer, so the AI community is currently addressing
just how much information a computer needs to behave
intelligently. This information can't be presented in a black-and-
white fashion if a machine is to emulate human intelligence.
People regularly make assumptions, jump to conclusions,
forget unimportant information and change their minds about
what they believe.
comfortable with fuzzy concepts like "if
and "maybe".
Boutilier's main research interest is in
laying the foundation for artificial
intelligence by working on ways that
computers can, in some ways, think more
like people. He is developing logics to
represent knowledge in a mathematical
form, while keeping it as close to the
English language as possible. That way,
computers can assimilate the information,
and people can understand and use his
method of representing knowledge.
Early attempts to develop artificial
intelligence were quite different from
today's approach. Researchers "taught"
computers to make fully-logical connections: to keep track of their beliefs, as
well as the reason for them; when the
reason changed, the belief changed. This
makes perfect sense, but is far too much
to keep track of, even for today's
"We have to teach a computer to forget,"
said Boutilier. People naturally forget
information that isn't useful, but a
computer has no way of separating the
wheat from the chaff. One could easily
program it to discard the information it
hasn't used for the longest. However,
some of that information may be crucial
on the rare occasions it is called upon.
Boutilier is interested in applying his
research to deductive databases that allow
for a certain level of uncertainty. "Smart"
databases exist today, but the type of
information they can impart is limited.
Boutilier would like to see databases with
the ability to respond to queries that
begin with, 'What if... ?' "Default
reasoning can be applied. Artificial
intelligence could extract the information
and draw conclusions for you," said
At first glance, many of the problems
Boutilier is wrestling with appear
straightforward. But he is finding that
when he delves into them, their complexity approaches the human mind's.
Boutilier's work forces him to think
about how we think and then find ways to
represent that logically — keeping in
mind that not everything we do is
perfectly logical. ■ Dinesh Pai
Pai researches machines that move
■ Dinesh Pai, a recent addition to the
Department of Computer Science, is
concerned with how machines move. His
research combines his knowledge of
robotics and computing.
Pai is working on how to program a robot
with a large number of degrees of
freedom. "In industry, they typically use
robots with six degrees of freedom, the
minimum amount required to operate in
three dimensions." However, that is
pretty limiting when you consider that the
human arm has about 25 degrees of
Currently researchers don't fully understand how to program for a large number
of degrees of freedom. Pai's approach is
to make programming easier by specifying constraints rather than the trajectory
of the robot limbs.
Pai used his approach in his postdoctoral
work and successfully programmed a
computer-simulated walking machine.
The LISP program not only demonstrates
stable walking from a full stop, but also
illustrates the problems that result when
you program steps that are too large (the
biped get stuck in a wide straddle
position) or too small (the machine falls
Pai has a strong interest on locomotion.
He has a wide assortment of locomotive
machines in his office. Most of them are
little toys that move in ingenious ways
when wound up: spiders that crawl, frogs
that hop, small pairs of feet that walk by
themselves. Many of these toys illustrate
simple concepts of locomotion that can
In the long run Pai's work and approaches like it will make life easier
for the working robot. Ironically, the same approach also makes things
easier for people working on assembly lines...
There are many assembly jobs that are tedious and hazardous, or for
which robots are faster and more precise, and these jobs will increase.
be applied in his research.
Pai is now considering building a legged
walking machine to study locomotion,
which could ultimately be used to traverse
rough terrain. He notes that the Japanese
have already built working robots that can
travel along the sides of ships and clean off
barnacles, reducing drag and hence, fuel
Pai is also interested in the singularities of
robot arms. (Singularities are the extremes
of motion possible — a fully-extended arm
would be one singularity.) In extreme
configurations, arms lose degrees of
freedom. Pai's work involves looking at
the structure of singular points to make
general statements about them.
One application of this work is to help
determine the best task locations for an
industrial robot arm. "The question of
where you put the assembly with respect to
the robot arm is clarified," said Pai.
Another project Pai is working on that will
make automated assembly easier is the
study of "motion diodes." These are simply
items that snap together and stay put, like
the cover for a cassette tape. Pai has
developed an algorithm that will predict
when motion will terminate (when the case
is snapped shut, for example) and if it will
stay that way. "We used computational
geometry and were able to develop a very
fast algorithm, taking friction into account," said Pai. "It will be useful for
industry. It's easy for a robot to assemble
equipment if everything snaps on."
However, he adds that it will be some time
before this work is incorporated into
standard industrial design practices.
In the long run, however, Pai's work and
approaches like it will make life easier for
the working robot. Ironically, the same
approach also makes things easier for
people working on assembly lines. When
IBM decided to automate production of its
Proprinter, the printer was completely
redesigned for robot assembly. Once this
was done, IBM found that while robots
could do the job, people could do it much
faster. However, there are many assembly
jobs that are tedious and hazardous, or for
which robots are faster and more precise,
and these jobs will increase, especially
when many of the problems Pai is working
on are solved. Gosine maintains practical perspective
on industrial automation projects
■ Industrial automation is the main
research interest of new Mechanical
Engineering Department member Ray
Gosine. While to some "industrial
automation" conjures up images of
workers displaced from their jobs by
robots, in fact, much of the work Gosine is
involved in improves already-automated
processes, or automates jobs that industry
cannot find people with the skill or desire
to do.
Gosine holds the NSERC junior chair in
industrial automation, which was set up to
research problems in industrial automation, especially as they relate to the fish
processing industry. Gosine and colleague
Clarence de Silva (who holds the senior
NSERC chair) have first turned their
attention to some specific automation
problems in fish processing.
One project involves minimizing waste in
salmon processing through more precise
cutting. This process is already automated,
but the equipment is old and employs little
advanced technology. About five per cent
of the salmon is wasted, yet if yields
increased by just one per cent, the
Canadian fish processing industry would
make an additional $5 million. (For more
information on this project, see CICSR
Focus, Fall 1991.)
Another interest of Gosine's is in motion
planning for robots, especially important
when they are put to work in cluttered
environments. "Most approaches are offline, and everything is pre-calculated,"
said Gosine. What he feels is needed is a
system that can rapidly generate a
collision-free path of its own using a
model of its environment.
Another project Gosine is interested in is
the improvement of fish spray-marking. A
method is needed to feed the fish through
a machine and spray them in a specific
place on their bodies, no matter what type
of fish is processed. Then, when marked
fish are caught later in their lives, equipment that can recognize the pattern, even
if it's worn or distorted, would be very
useful. This identification would require
knowledge-based vision, another of
Gosine's interests.
Machine vision is also necessary for
"A lot of engineering work
could be applied to the problems
experienced by disabled people.
In some areas of engineering
you can do a lot technically and
not accomplish much
practically. Working directly
with disabled people forces you
to keep a practical perspective."
automated herring roe grading, a project
Gosine hopes to start this summer. Roe
grading takes a great deal of skill, but
B.C. Packers is finding it increasingly
difficult to find people willing and able to
do the job. Grading is very important
because herring roe buyers are very
particular about the quality of the product
they receive. Grading is also very
subjective, so an automated system would
require the use of fuzzy logic and an
expert knowledge base to do the job well.
Gosine hopes to work with the Computer
Science Department on this problem.
Gosine is also interested in the development of better robotic devices for
handling objects. "I want to look at
multiple-degree-of-freedom joints that
could conform to the shape of an object
— joints that could be more gentle by
determining which object is present and
what is the optimal grasp. This work
would not only apply in industrial
automation, but in robots to help the
Gosine is exploring ways to ease the use
of telemanipulators for the disabled. This
project, linked with the Neil Squire
Foundation and Simon Fraser University,
is now progressing on a small scale, but
Gosine hopes to expand the program by
summer and involve Shaughnessy
Hospital as well.
In collaboration with mechanical
engineering professor Doug Romilly,
Gosine is building an exoskeleton for
Ray Gosine
people with flail arms. People with this
disability can't move their arms, though
the limbs have sensation. The goal of the
project is provide these people with the
ability to move their arms and perform a
number of natural movements we take for
granted. The first step is the study of the
way people with fully-functioning arms
move to complete basic tasks like eating
and washing.
While working on his Ph.D. and
postdoctoral work at Cambridge, Gosine
focused on research in robots for the
disabled. "It's nice to find there are similar
interests here," he said. "A lot of engineering work could be applied to the problems
experienced by disabled people. In some
areas of engineering you can do a lot
technically and not accomplish much
practically. Working directly with disabled
people forces you to keep a practical
perspective." ■ Parallel computing winning the race
■ Hussein Alnuweiri, a new assistant
professor of electrical engineering, is
interested in parallel processing and
implementing highly-concurrent computer systems in VLSI (Very Large Scale
Integration) technology. His research
application areas include signal processing, image analysis, computer vision and
algorithmic graph theory.
VLSI has advanced considerably in the
past decade, Alnuweiri reflects. By the
year 2000, it will be possible to pack
about 100 million transistors onto a single
chip. It will be possible to build a parallel
processing system on one chip.
However, the future aside, VLSI is
currently a rather restricted medium
compared with previous technologies.
Both the number of layers in which wires
can be routed and the number of input/
output terminals are limited and, with
decreasing feature (transistor) size,
sending signals along long wires poses
many difficulties.
While Alnuweiri's research considers
several interacting trade-offs in application-specific VLSI designs, his major
Hussein Alnuweiri
goal is to resolve several communications
problems associated with embedding
parallel and distributed systems in VLSI.
He is currently involved in developing a
number of chip designs which can perform
permutation routing efficiently on a VLSI
chip. These designs can be used to perform
data routing between processing stages.
According to Alnuweiri, the main problem
in designing VLSI networks for parallel
computing is in routing the data between
processing units. "That's usually where the
bottlenecks occur," he said. "The networks
I'm working on overcome many of these
difficulties." Alnuweiri's design separates
... continued on page 8
Electromagnetic theory revisited by Howard
Gregory Howard
■ Electromagnetic theory, synthesis and
analysis are the main research interests of
new electrical engineering professor
Gregory Howard.
According to Howard, the main problem
with analysis of electromagnetic circuits is
the large number of unknowns present.
This makes it difficult to get meaningful
results. "You need post-processing to make
final results meaningful for a designer,"
said Howard.
His Ph.D. work involved developing a set
of tools to reduce the computation time for
problems where unknowns numbered in
the thousands.  He developed a multi-level
technique which allows the computer to
come up with an approximate solution
while reducing computation by an order of
Howard is looking at new techniques to
analyze electromagnetic circuits. Current
circuit theory entails the use of block
component modelling, which accounts for
each individual block fairly accurately, but
doesn't account for the interaction of that
block with its environment. To incorporate
all of the interactions between complex
electromagnetic systems is a feat too large
for even powerful modern computers.
Howard worked on a new approach for
both his Masters and Ph.D. theses, and is
continuing with this research. His method
of circuit analysis allows for the inclusion
of the electromagnetic coupling. His
approach emphasizes integral equation
methods and their use in a new integrated
form of circuit theory.
Howard points out another drawback to
traditional methods of electromagnetic
... continued on page 8 Passing notes
Vinod Modi wins
Brouwer Award
Parallel computing
... continued from page 7
Electromagnetic theory
... continued from page 7
Mechanical Engineering professor
Vinod Modi is the first Canadian in
history to receive the Dirk Brouwer
Award, the most prestigious offered by
the American Astronautical Society.
Modi's research in aerospace engineering focuses on the dynamics and
control of large space structures,
including the next generation of
communications satellites, space
shuttle-based experiments, the
proposed space station Freedom and
mobile remote manipulator systems. ■
ceremony held
■ A ribbon-cutting ceremony was held
in December to officially celebrate
construction of the new CICSR
The $18 million building will bring
together the departments of Electrical
and Mechanical Engineering, as well
as Computer Science. All three
departments have grown considerably
in recent years.
The building will also be the new
home of CICSR, and will enable the
Centre to better facilitate interdisciplinary work among its members.
UBC president David Strangway, B.C.
Tel chairman Gordon MacFarlane,
CICSR director James Varah and
Tourism and Culture minister Darlene
Marzari were among those present at
the ceremony. ■
networks into chip areas that do processing, and chip areas that do the routing.
Alnuweiri started his research in his Saudi
Arabia. He also spent five years in the U.S.
at the University of Southern California
where he earned his Ph.D. in computer
engineering. A prototype chip is now being
produced based on his design which can
perform permutations on 256 inputs
Alnuweiri is also working on designing
algorithms for reconfigurable networks of
processors. These are networks which can
change their topology dynamically
throughout a computation. Their application would be in areas where very fast
solutions are required, such as image
processing and robot vision. But the work
is still in the research phase and has a way
to go before it can be applied.
The applied nature of the discipline is what
attracted Alnuweiri to electrical engineering. His earlier interest was physics, but he
says, "I like design problems and to see a
product out of what I study."
His chosen field is one of the fastest-
growing engineering fields. "There are a
lot of emerging technologies and all
require a substantial amount of research,"
said Alnuweiri. He feels, like many others,
that parallel computers are the way of the
future. In fact, several parallel computers
have emerged in the last few years, with
others soon to follow from most of the
companies that now produce mainframes
or "traditional" supercomputers.
"Traditional supercomputers and
mainframes are losing the battle. Massively parallel computers will dominate the
future of supercomputing." However, there
is still a lot of work to be done before these
computers of the future become widely
used. Alnuweiri is doing a part of that
work. ■
circuit analysis, which his approach could
help overcome: "Present techniques are
limited by the fact that they use linear
operation techniques. A new method is
needed to analyze non-linear materials."
Another strong interest which Howard is
pursuing could save electromagnetic
researchers a lot of redundant work in the
future. "When doing research in numerical electromagnetics, new researchers
start almost from scratch because the way
the code was previously written, it is not
re-usable," said Howard. He would like to
see this change through wider use of new
software tools and object-oriented
languages so code can be extended for
new applications without researchers
having to re-invent the whole underlying
This approach would also make implementation of new methods and techniques, such as the one Howard is
working on, easier to implement within
existing work. "It would make it easier for
researchers to collaborate if code writers
used the same design methodology," said
Howard is interested in collaborating with
the Computer Science Department to
solve another fundamental difficulty in
electromagnetic circuit research. When
dealing with electromagnetics, the amount
of information that needs to be processed
is so large, a very friendly user interface
is required for people to process that
information. Howard hopes to collaborate
on the development of an interface which
will allow his analysis tools to be used by
industry in a reasonable, rather than an
expert, fashion. Electromagnetic circuits
are used in satellite communications,
radar, modulation circuits in fibreoptic
technology, and many other areas. ■
The UBC Centre for Integrated Computer
Systems Research (CICSR) is an interdepartmental research organization made up of computer-
related research faculty members in the
Departments of Computer Science, Electrical
Engineering and Mechanical Engineering.
Currently there are more than 60 CICSR
researchers which direct over 100 graduate
students and collaborate with dozens of industrial
firms in areas such as robotics, artificial
intelligence, communications, VLSI design and
industrial automation.
CISCR FOCUS, is published twice a year.
EDITOR:  Leslie Ellis
DESIGN:  Rob Bishop
Office: 2053 - 2324 Main Mall,
Vancouver, B.C. V6T 1Z4
Tel: (604) 822-6894, fax: (604) 822-9013
Contact: Gale Ross


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