Simon, Martin, "System Dynamics in Engineering Education", 1995

Parallel Program

System Dynamics in Engineering Education

Martin Simon, Hans U. Fuchs
Technikum Winterthur
P.O. Box 805
CH-8401 Winterthur, Switzerland

fax: +41 - 52 - 46 35 13
phone: +41 - 52 - 46 20 25

Abstract

System dynamics can play an important role in the education of engineers. On the one hand, stu-
dents in engineering profit from system dynamics. On the other hand, the system dynamics
methodology can be enhanced if we take advantage of the training in physics and mathematics re-
ceived by the students. It is found that new forms of teaching physics (systems physics) support
systems thinking in a unique way. Advanced courses in engineering disciplines can then build
upon modeling and simulation taught early on in the curriculum.

1 Introduction

Graduate engineers form the major body of the work force with higher education in industrialized
countries all over the world. Educating engineering students today means shaping the mental mod-
els applied by this work force tomorrow. Therefore, not only managers but also engineers should
be trained in the general methodology of system dynamics. That way system dynamics contributes
to the creation of the future learning organizations.

At Technikum Winterthur (TWI) we have used systems thinking and system dynamics in
courses within the departments of physics, mechanical engineering, electrical engineering and
chemical engineering. We have employed system dynamics at introductory through intermediate
levels, and we have taught graduate courses specifically designed for training SD-modelers in dif-
ferent professional fields.

This paper first describes the rationale behind our decision to use system dynamics in the
training of engineers. It goes on to discuss the unique role the teaching of physics can play in this
educational process by outlining the feedback relationship between system dynamics and a general-
ized form of classical physics (systems physics). Finally, our experience with a concrete example
of a course using the system dynamics methodology is described.

2 Coping with change in engineering education

Fueled by changes in society and in the relation between society and nature, engineering education
is undergoing profound transformations. This section will briefly list forms of change and discuss
a model of how system dynamics can be instrumental in accompanying us through times of
change.

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Transformations in engineering education

The driving forces behind change in engineering in general and in engineering education in particu-
lar are very much the same as those found in other areas of human endeavor. Put simply, we are
facing problems of increasing complexity at an accelerating pace. Not only do we find ourselves in
a highly dynamical situation, the particular tasks encountered by the profession increasingly de-
mand knowledge of the behavior of dynamical systems at the technical and mathematical level. Just
consider the field of renewable energy engineering for which steady-state models of classical en-
ergy systems simply do not suffice any longer; the variability of the natural environment combined
with the necessity for storage elements make regenerative energy systems highly dynamical.

Some of the change we would like to describe here has to do with the particular situation our
school (TWI) finds itself in. In order for you to understand the possibilities of leverage for the
system dynamics methodology, you should be aware of the special circumstances at TWI. Our
school is an undergraduate engineering school which is undergoing rapid transformation from a
Swiss Polytechnic to a European Engineering College as they emerged in Britain and Germany
some 20 years ago. As far as science and engineering go this transformation has meant a strength-
ening of the role of applied research and development which in turn has led to a marked build-up of
the application of modeling and simulation at TWI.

Last but not least we will fuse with the School of Business and Administration of the Canton of
Zurich (HWV Zurich) to a College of Engineering and Business/Administration. More than any-
thing else, this change might bring with it opportunities for applying system dynamics for fostering
a true shared understanding between the two sides which up to now have been independent of each
other. Again, energy engineering proves the point. In the future, energy engineering will not
achieve its potential without simultaneously considering energy management and the role of the in-
teraction of energy and society.

How to cope: a model for identifying areas of leverage

Whereas the initial buildup of the students’ knowledge about system dynamics has to be provided
by their teachers, we found that courses putting more emphasis on system dynamics methodology
have a strong self-enhancing component. It is clearly not the self-enhancing process which is
amazing but the thoroughness of this process, it’s speed, and the momentum it creates. We hy-
pothesize this to be a result of (1) an increasing relevance of the SD approach to dealing with dy-
namical problems professional engineers encounter in their fields, and (2) the SD approach in itself
creating positive feedback in taking engineering problems head on that look insurmountable with-
out SD methodology. A simple model reveals the main areas, where a SD approach could add
value to the educational process.

Figure 1 presents a rough mapping of the educational process students at TWI undergo. The
main chain on top represents the process for one out of three or more groups of about 25 students
within one of the departments of the school (Mechanical, Electrical, Chemical, and Civil
Engineering, and Architecture). For simplicity’s sake, the model assumes that the students all pass
the exams. The first conveyor in the chain depicts students of a single group during their first and
second years; during this time the students receive all their training in the same initial grouping.
The second conveyor represents the same group of students during their third year.

During the first two years, each group of students essentially has a different set of teachers.
However, all of the courses in mathematics, physics, and in computing are given by a pool of
teachers shared among the departments. This defines the first area of leverage for a SD approach.
The unique role teachers of physics and mathematics can play in first and second year education is

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the result of the following three facts: (1) teachers of physics and mathematics have the possibility
of creating the basis for a more unified view of dynamical processes by employing SD methodol-
ogy early in the process; (2) as these teachers can reach across the borders of the departments, they
are able to efficiently spread a systems thinking approach, thus invigorating the students’ capabili-
ties of coping with interdisciplinary project work and applied research and development later on;
(3) once physics has been understood as a historically grown and experimentally validated way of
modeling nature expressing relationships in the form of laws, physics can be used for an immense
reservoir of rich and meaningful models. Of course, these could easily be translated into simulation
models, as the laws also provide for the mathematical relationships. But then, this merely would
mean to replace the brain as the simulation engine by a computer. Instead, physics teachers should
tap into the fundamental resource of physics as a highly effective facilitator in the process of learn-

ing how to model. How this can be done by teaching physics will be explained in more detail in the
next section.

Students of group A in first & second year Sin third year

ara ik

passing entrance exams

Professionals having to cope with change

uO

‘passing intermediate exams _ passing final exams

Students in elective using little SD

looking elsewhere

Students’ Knowledge about SD

decision rules

looking for SD building up

Students of group B

Physics & math teachers’ Knowledge about SD
increasing .

Students of group ¢ Students’ Knowledge about SD

C’) teacher’s required level of knowledge

Professionals having to cope with change

Figure 1: A rough mapping of the educational process a student at TWI undergoes. The map helps
to reveal areas of leverage for teaching SD concepts.

After two years, having passed their intermediate exams, the students of all groups have a

choice between several elective courses, along with courses in the core subjects within their re-
spective departments. This can be modeled by a common stock of students ready for electives.

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Figure 1 shows the inflow to this stock driven by the outflows of students of group A through C
(groups B and C depicted by compressed symbols). Here we have identified a second area of
leverage for SD concepts. The familiarity of students with what they have been taught during the
first two years naturally influences their choice. However, the more confidence the students build
in the applicability of system dynamics concepts and the more convincing its cross-disciplinary
potential appears to them, the more easily they cope with new challenges provided by complex
tasks in the field of engineering. Thus, by using SD concepts early on, a teacher will be able to
pick up topics in an elective course that go beyond tradition. We have done this for example in a
course on solar energy engineering. The results are described in section 4.

There are still more implications in the model presented in Figure 1. By looking at the map one
easily detects at least two positive feedback loops in the center of the diagram. (1) The practical rel-
evance of the students’ knowledge about SD acquired in their first elective course influences their
decisions wether or not they should take another one-semester course stressing SD-concepts. (2)
Students familiar with systems thinking ask different questions. This gives their teachers a clear in-
centive to improve their own systems thinking skills. Also, there is feedback from older students to
the decisions of newcomers, which is not expressly included in the map.

Still another loop shows highly important feedback from professionals having to cope with
systems of ever increasing complexity in their field of engineering. After having passed their final
examinations, the students finish their studies with thesis work. Most of the theses are prepared by
project work lasting for one or two semesters during their final year. By communicating their ex-

perience back to their former teachers, professionals are able to stimulate SD-related topics for the-
sis work.

3 Teaching systems thinking by teaching physics

The first major steps toward systems thinking and system dynamics can be taken in undergraduate
physics courses which are part of the engineering curriculum. In this section we would like to ex-
plain why this is so and how the goal can be achieved.

The relationship between physics and systems thinking

It certainly should not come as a surprise that physics and system dynamics have some form of re-
lationship. Physics provides for the premiere example of mathematical theory building and of
mathematical modeling. We should not underestimate the influence of physics upon our belief that
nature is amenable to modeling which leads to predictions of the outcome of physical processes. In
this manner physics provides one of the cornerstones of control theory (see Figure 2).

However, in at least two important ways their relationship is strictly limited. First, feedback
thought is rather underdeveloped in physics which explains why this crucial ingredient of control
theory was borrowed from biology (Fig.2). Secondly, the relationship is completely one-sided:
physics has not been influenced by the engineering disciplines of systems theory, cybernetics, and
control theory, at least not in its foundations and in its teaching.

System dynamics has evolved on the basis of control theory out of a desire to apply systems
thinking to other than just engineering control systems (Fig.2). Generalizations of this nature often
mark important transitions from one paradigm to another. A paradigm shift of some sort has also
taken place in the foundations of classical physics during the last three or four decades in the form
of a generalized version of continuum physics (Truesdell and Toupin 1960; Truesdell and Noll
1965; Truesdell 1984; Miiller 1985). This generalization of the foundations has recently been trans-

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ferred to the introductory level which has led to the teaching of what might be called systems
physics (Maurer 1990; Fuchs 1996; Burkhardt 1987). It is interesting to see that the relationship
between the generalized versions of control theory (system dynamics) and of physics (systems
physics) is of a much deeper nature than the one enjoyed previously by physics and control theory
(Fig.2).

gereralized modeling

Continuum Physics
Systems Physics

System Dynamics

physical ST

control theory

math. ‘seasons 7 of
Y_piyscal systems systems

feedback

biology

Figure 2: Relationship between physics and control theory on the one hand, and between their gen-
eralizations, namely System Dynamics and Systems Physics.

Physical systems thinking

Put simply, both continuum physics and systems physics use at their core the image of the flow,
the production, and the storage of physical quantities such as electrical charge, momentum, and
entropy. While this image has not yet been used extensively in the presentation and the teaching of
physics, it is well known to anybody familiar with the notion of stocks and flows as they are em-
ployed in system dynamics modeling. Now, what systems physics has to bring to systems think-
ing is an example of processes where the image of flow, production, and storage, and the neces-
sary constitutive relations for the flows can be cast into a precise, well known form. Therefore, in
our view, physical systems thinking can furnish a secure platform for the learning of systems
thinking and system dynamics.

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System dynamics and systems physics

The reverse of the relationship just outlined is very important as well: the system dynamics way of
modeling can be employed as a vehicle for teaching the modeling process in systems physics
(Fig.2). We can even make this modeling process the core of what we expect (engineering) stu-
dents to learn from their physics courses, which would mean that system dynamics becomes the
paradigm of new ways of teaching physics. Experience at TWI (Maurer 1990; Fuchs 1996) shows
the this goal can be achieved.

Taking a close feedback relationship for granted, system dynamics and systems physics not only
profit from each other but provide for a synthesis at a higher level as well. If you consider the abil-
ity of engineering students to deal with interdisciplinary problems and to apply the modeling pro-
cess as increasingly important, then the new relationship between system dynamics and systems
physics may serve as a tool for bridging the widening gap between theory and application.
Looking at physics as the theoretical side of (much of) engineering, students adept at modeling dy-
namical processes will not shy away from what otherwise might be considered to be too difficult,
namely the application of theoretical foundations to their practical profession.

4 System dynamics-based solar energy engineering as a model

We have built up a two-semester course on solar energy engineering at TWI. It is one of the list of
elective courses students of mechanical engineering have to choose from. As described in section
2, students have gone through their first two years before this point. From the very beginning in
1989, we have built the concept of our course on aiming at the interesting dynamic features solar
thermal systems exhibit. Therefore we have used SD methodology and systems physics to intro-
duce students to this complex field of mechanical engineering.

After an introduction to the foundations of solar energy engineering and a spectrum of its ana-
lytical methods and design tools, we encourage and strongly emphasize a shift of attention towards
modeling of solar energy systems as a means of thoroughly understanding their behavior. Students
mainly use STELLA when modeling complete solar energy systems or parts thereof. Although
STELLA is of very limited use for the simulation of rigorously modeled solar systems, it is a valu-
able tool for doing the first steps in the modeling of more complex examples of engineering appli-
cations. At the end of the first semester students have to choose from a variety of topics to do pro-
ject work in the following semester. We have offered topics for project and thesis work in the field
of modeling such as a comparison of different modeling approaches for seasonal heat storage for
solar energy applications.

The first course on solar energy engineering started in 1991 with 12 participants. In subsequent
years 18 students, then 27 students and eventually 35 students signed up for that course. The ex-
ample of thesis work done by two students as a team and finished in 1994 clearly shows the value
SD concepts can add to the field. One of the students had to construct a solar domestic hot water
system for experimental work. The other student’s task was to develop in parallel a simulation
model which would mimic as closely as possible the solar hot water system constructed by the first
student. The model was developed with MATLAB/SIMULINK. Although they had one semester of
project work to prepare for their thesis work (which lasted for only 6 weeks), the complexity of the
problem went well beyond what traditionally could be expected under time and resource limited
conditions prevailing during thesis work (Bontognali 1994; Meyer 1994).

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5 Summary

The following lists a number of observations we have made during the years of building up system
dynamics related topics within the curricula of some of the departments at our school.

¢ As long as K12-education in System Dynamics is not standard, the SD-training of the stu-
dents requires active reversal of their normal mental models from static to dynamic ones.

_* The System Dynamics approach enhances both the traditionally taught skills of the students
and their willingness to keep learning beyond graduation.

+ Besides delivering a multitude of interesting applications, physics provides for a particular
way of systems thinking which can be of great advantage in the teaching of system dyna-
mics.

¢ Teaching and thesis work have given us extensive experience with integrating system dy-
namics in an engineering curriculum. The available computer tools for building models al-
low for developing more precise mental models of dynamic processes such as in physics,
chemistry or energy engineering. By learning about SD early on, students are able to reach
beyond usual limitations. SD has proven to be an excellent learning tool for exploring com-
plex engineering problems and preparing sustainable solutions. Without getting bogged
down in non-conceptional details, students acquire practical experience for a thorough dis-
cussion of mathematical implications later on.

¢ Through the emphasis on structured thinking and the commitment to sustainability Systems
Thinking apparently fosters the necessary consciousness for high quality work on the job.

* The Systems Thinking framework provides students as well as professionals with a con-

cise language for discussing complex problems on the basis of shared understanding des-
pite different backgrounds.

References

Bontognali, M. 1994. Eine solarthermische Anlage am Technikum Winterthur. Diploma Thesis,
TWI, Switzerland.

Burkhardt, H. 1987. Systems physics: A uniform approach to the branches of classical physics.
Am.J.Phys. 55, 344-350.

Fuchs, H.U, 1996. The Dynamics of Heat. Springer-Verlag, New York (to be published).

Maurer, W. 1990. Ingenieurphysik auf neuen Wegen. Technische Rundschau 82 (29/30),12-16.

Meyer, R. 1994. Systemdynamisches Modell fiir die solarthermische Anlage am TWI. Diploma
Thesis, TWI, Switzerland.

Miller, I. 1985. Thermodynamics. Pitman, Boston.
Truesdell, C. 1984. Rational Thermodynamics. 2nd ed. Springer-Verlag, New York.

Truesdell, C.; Noll, W. 1965. The Non-Linear Field Theories of Mechanics, in Encyclopedia of
Physics, v. Ill/3, S.Fliigge ed. Berlin, Springer-Verlag.

Truesdell, C.; Toupin, R.A. 1960. The Classical Field Theories, in Encyclopedia of Physics, v.
Ill/1, S.Fliigge ed. Berlin, Springer-Verlag.

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