Systems Engineering

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.

• Particular attention is given to defining the functions of the system and its subsystems. There is a strong tendency on the part of people in general, and engineers in particular, to pass quickly and casually through the problem-definition phase of system design and focus almost immediately on solutions. A satisfactory solution to the right problem is often better than an excellent solution to the wrong problem.
• It includes mechanisms to encourage coordination, cooperation, and clear communication among all participants; those participants includes users, financiers, and government regulators.
• Some person or group articulates the whole in a conceptually clear fashion. This articulation enables the participants to understand the whole and enables them to contribute effectively. For a complex system, this articulation probably implies decomposing the system into a few subsystems with simple subsystem interfaces. For most systems, the conceptualization and decomposition relate primarily to the decision-making structure and information flows in the system.
• It uses planning/scheduling procedures that promote rapid convergence of design iterations and rapid recognition and isolation of mismatches, faults, flaws, etc. These procedures almost certainly require gradual implementation of the system -- small steps rather than large.
  

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.