Engineers design and develop systems to meet user needs. Most systems
are complex. The design and development of a complex system involves many
participants from various specialties. Systems engineers, in particular,
specialize in those issues that have to do with the effectiveness of
the whole system.
What is an effective system? One that satisfies the users (or stake
holders) and is flexible enough to be modified or upgraded as the user
needs and environment change. To satisfy the user, it must have a satisfactory
cost/benefit ratio, and that ratio must compare favorably with alternative
systems. In the city, for example, the automobile-transportation system
competes with one or more public transportation systems such as taxis and
urban mass transit. On a smaller scale, the automobiles of one manufacturer
compete with those of another manufacturer.
All product designs require iteration. Unforeseen consequences or side
effects always appear when a new product is used. These consequences demand
modifications to the product. Complex systems are composed of parts and
subsystems, each of which undergoes iteration in its design and development.
In addition, there are mismatches between the initial subsystem designs,
owing primarily to inadequate understanding by subsystem designers of the
workings of the larger system.
Unfortunately, the various participants in the design and development
of a new system (or the modification of an existing system) are often not
even aware of each others' existence. This lack of awareness limits their
view as they contribute to the whole (or to a subsystem). This limited
view leads to unnecessary iteration in the design and development processes.
The participants also tend to limit their view to the initial
life of the system or subsystem. This limited-time view leads to components
or subsystems that cannot accomodate the changes that an evolving society
requires, and can cause early obsolescence of the whole system.
The parts of a system are always imperfect. In order for a system to
work effectively, the system as a whole must accomodate or tolerate imperfect
performance of the parts.
The art of system integration is the use of
procedures of thought and action that exhibit the above four characteristics
during system design and development. This art is best acquired by experience.
The curricula of the Department of Systems Engineering help students acquire
this art and the associated situational awareness through appropriately
guided team design experiences.
The core courses of the Systems Engineering Department deal primarily
with issues that pertain to whole systems (or whole subsystems); these
issues include problem definition, mathematical or computer modeling of
complex systems (including physical, economic, and social-preference variables),
optimal decision making (perhaps with multiple criteria), decision-making
and predicting with uncertain information, and procedures for conceptualizing
and controlling system behavior.
Most systems have mechanical, electrical, and other aspects to them. They usually include one or more computers as well. For detailed design and analysis of these aspects of a system, we usually turn to a specialist in mechanical, electrical, or computer engineering. The specialty of the system engineer is in integrating the pieces of the system into an effective whole. These pieces are typically not mechanical, electrical, or computer in nature, but rather, functional in nature; hence, they often belong more nearly to the systems engineering specialty than to any other. The combined efforts of engineers of various specialties are needed to produce an effective system.