Ms2004 Round Table
"Contribution of Models to Research"
Panel: Dr Laurence Cheze (France, Biomechanics), Pr
Houcine Chafouk (France, Automatic control), Pr Lionel Collet
(France, Physiology), Pr Norbert Dillier (Switzerland, Audiology),
Pr Nashaat El-Khameesy (Egypt, Economy), Pr Aladin Zayegh
Moderator: Pr Christian Berger-Vachon, Dr Emmanuel Perrin
Question 1: "What is, in your field, the contribution
Dr Cheze: Several subfields are considered: Human
movement, car crash
The clinician collects the in vivo
data and mechanical engineers build up a model corresponding
to that behaviour. Then a quantification is made using numerical
analysis. In sport, gestures are studied. Modelling cannot
be conceived without a validation.
Pr Dillier: When we try to understand how the human
body works, we are thinking in terms of models. In my field,
models are used for improving auditory prostheses. For example,
they are part of loudness compression and feedback cancelling
algorithms in hearing instruments to reduce the "whistling"
effect. Simulation techniques for biological phenomena have
been widely covered in the keynote address.
Pr Collet: Physiology of the organ of Corti is a true
example. The first auditory model built up by Von Bekesy explained
the frequency analysis done by the ear and he won the Nobel
Prize for this discovery, but it did not explained the amazing
In 1961 Gold pointed out the fact that Von Bekesy worked on
a dead cochlea.. and some life action was likely to occur.
If so ears could emit sounds. In 1978, David Kemp recorded
otoacoustic emissions and it has been established that they
reflected active mechanisms at the level of outer hair cells.
In future, we would like to model the influence of aging on
the auditory system and the signal to noise ratio influence.
Pr El-Khameesy: Modelling started with engineers and
was extended to business. We had to find adapted tools in
our field, such as marketing, and to introduce intelligent
In marketing, multilayers models are well adapted and semantics
becomes part of the model.
Pr Chafouk: The example is the automatic control a
system following a human behaviour.
Let us take the example of vehicles and pollution. Models
of particle emission are established, and simulation of motors
is made (from the pollution point of view). Models to reduce
the emission of particles are then made and a validation with
a motor is done. It is easier (and cheaper) to work on models
than to work on motors. Interesting solutions are then tested
with real motors. The issue is the planet (environment)
it concerns cars and planes. Although airports are built in
open land, pollution in the neighbourhood is rather high.
Pr Zayegh: In engineering and science education, modelling
and simulation are vital tools nowadays. They provide students
with facilities which can maximise their understanding in
many areas in short time and minimum cost. For example, in
experimental work, the following steps are necessary:
-The preliminary work based on theoretical analysis can be
consolidated and justified by modelling and simulation. The
students go to the laboratory with "open eyes".
-In many cases models can be developed, programmed and tested
before physical assembly of such system (Feasibility study
in many system design)
Theoretical results, simulation results and experimental results
are compared to consolidate and justify many design projects,
-modelling is quick and cost effective method in many cases.
It is the practical solution in high cost, high risk areas.
It is the logical step before physical prototyping.
Many models are components in a library, they can be assembled
to develop large systems. There are some areas where modelling
and simulation are the only passage for teaching. For example,
in microelectronics, millions of transistors and other components
are used in integrated circuit design. That cannot be physically
implemented in education environment. We start with a simple
model of transistor and finish up with sophisticated architecture.
Question 2: Do you use models in education?
Pr Zayegh: Modelling and simulation are educational
tools; models are "virtual reality". We must not
loose the track and accept modelling to replace mathematical
analysis. The proper education process should have the following
steps in problem solving:
-hand analysis and calculation, modelling and simulation results,
practical results from physical system and comparison for
understanding and improvement.
Pr El Khameesy: educational programs for students
should contain "model boxes". With model boxes we
build up big simulators such as plane pilot simulators or
Pr Dillier: Simple exercises to get used with the
methodology are taken first and then students go deeper into
the more complex model systems.
Dr Cheze: In mechanics, finite elements models are
classically used in teaching sessions.
General remarks from the audience
1) Students try to avoid mathematics and now formula are
introduced (and hidden) in the model boxes.
2) Industry does not like models too much, it prefers real
behaviour. In models too many assumptions are made, and one
can become suspicious.
3) Uncertain models simulate man's behaviour. Fuzzy logic
brings bits of human uncertainty into the models (human being
cannot always be predicted). This family of non deterministic
models should be a new step in modelling.
Finally: Model is not only an efficient tool in Research,
t is also a true science in itself, true science which is
worth to be taught and used wisely