Space And Climate Physics

Meanings of systems engineering

When people use the phrase systems engineering, they have in mind one of the following meanings:

1. The INCOSE definition,

2. A sub-field of electrical engineering,

3. A sub-field of industrial and systems engineering,

4. A sub-field of engineering management or technology management,

5. The information technology definition, or

6. Systems engineering based on systems theory. We now discuss each of these meanings.

1. INCOSE: According to INCOSE (International Council on Systems Engineering),13 Systems Engineering is an interdisciplinary approach and a means to enable the realization of successful systems. It focuses on defining customer needs and required functionality early in the development cycle, documenting requirements, then proceeding with design synthesis and system validation while considering the complete problem. Practitioners of system engineering in this meaning focus on one-time, large projects with a definite start and end, where a new system is to be designed and created to meet customer needs. Practitioners focus on industries such as information technology (IT), aerospace, and defense. On job posting sites (e.g., monster.com), the phrase systems engineering almost always describes a job in the INCOSE model, usually in the aerospace or defense industries.

2. Electrical engineering: Within the electrical engineering field, emphasis is attached to the use of systems theory in applications, e.g., spacecraft manufacture and management. As such, systems engineering within electrical engineering tends to emphasize control techniques which are often software-intensive. It appears that one of the first uses of systems engineering was in Bell Labs.18 Managing complexity is an important ingredient of many courses taught within these programs. Modeling, simulation, reliability, and safety analysis of complex systems are considered to be essential parts of the training needed for a successful systems engineer.

3. Industrial and systems engineering: This meaning is the hardest to pin down. Often the phrase industrial and systems engineering is used interchangeably with industrial engineering. Industrial engineers create a new system or improve an existing system, The word system is meant to remind the IE of three key points which IEs emphasize more than other engineering disciplines: (1) components (including machines and people) interact with each other to create the overall behavior of the system& (2) the system being studied is always a subsystem of a larger system and these interactions must also be considered& and (3) systems include humans. The word system is a caution against sub-optimization of the larger system through optimization of a subsystem. Because Industrial Engineering academic departments often include a wide range of areas (physical and cognitive human factors, manufacturing processes, operations research, engineering management, etc.), the word systems often appears to be an attempt to be inclusive. Also, some think that the word industrial doesn t include the full range of what industrial engineers do. Industrial and systems engineering can apply to service companies, hospitals, insurance, etc.

4. Technology management or engineering management: In technology management, systems engineering includes taking into consideration all aspects of the life cycle of the system. Thus the systems engineering approach is said to account for manufacturability, installation, operations, maintenance, repair, and disposal of a system. When manufacturing or selling a product, a systems engineer is likely to view the current technological phase of the product as a critical feature. For instance, in the early 1990s, cell phones were in their early technological phases. Designing, manufacturing, and selling cell phones in those years were activities achieved with objectives and mechanisms that were different than those employed in the first decade of this century. A systems engineer is acutely aware of this issue when considering every aspect of managing a business and designing a product. For managing a project, system engineering forces the manager to define the goals and objectives of the project. The project manager with an understanding of the systems viewpoint is capable of knowing the difference between the long-term goals and short-term goals, and can focus on the long-term goals when making strategic decisions. Indeed, the issues of life cycle development are prominent within the literature on project management, and hence they have had an impact on systems thinking by project managers. Another important focus of systems in engineering is from the so-called perspective of engineering design. In this setting, designing a complex system often requires an evaluation of different alternatives available to the designer. The systems engineering approach is a framework that can provide data on the many disparate variables that lead to different alternatives and ultimately influence the choice of design.12 It is often said that the systems viewpoint is also adopted when there are significant inter-related variables within the problem domain that need to be accounted for in a unified holistic approach. A mastery of mathematical, statistical, and quantitative techniques is expected of a systems engineer in order to successfully design a product and manage a product.1 The design perspective of systems engineering, also emphasized within engineering management, stresses the importance of measuring risks associated to a decision.12 Decision analysis can then be used to make intelligent decisions with respect to choices.

5. Information technology: A new discipline has emerged in the business schools and computer science departments that goes by the name information systems (which is often a minor in computer science departments) or management of information systems (usually in business schools). This definition of systems engineering tends to focus heavily on the interface of computers with the business world.14 While this has emerged as a discipline in its own right, it appears that this definition is also related to the INCOSE definition. Students in this discipline are expected to become experts in database management, computer security, and transaction processing. In this respect, this definition significantly deviates from what is understood as systems engineering in industrial and electrical engineering departments. However, from the perspective of potential employers, this definition seems to be widely used on jobsites.

6. Systems theory and philosophical origins of systems engineering: Various authors have written on the more philosophical roots of systems. Some of them are: Churchman5,6 on the systems approach, von Bertalanffy19 on General System Theory, Stafford Beer2 on the Viable Systems Model, Jay Forrester10,11 on systems dynamics, and Peter Senge.17 We now discuss some of their ideas in order to expose the roots of systems engineering in other disciplines. These foundations also perhaps explain why systems engineering has naturally become an inter-disciplinary approach. Ludwig von Bertalanffy s General Systems Theory has roots in biology. He wrote:19 In order to understand an organized whole we must know both the parts and the relations between them. The primary model is that of an open system, that is, a system exchanging matter with environment as every living system does. Cybernetics emerged from military work, says Bertalanffy, yet ended up also challenging the mechanistic descri ption of systems. A central tool of systems science is a mathematical model, often described in differential equations. A central notion is stability, that is, the response of a system to perturbation. Thus, dynamical system theory is closely related to control theory. Applying general systems theory to problems in hardware and software leads to systems technology. Finally, the reorientation of thought and world view following the introduction of system as a new scientific paradigm (in contrast to the analytic, mechanistic, linear-causal paradigm of classical science) is in the realm of systems philosophy. Stafford Beer3 applied ideas of cybernetics to human organizations in works such as Brain of the Firm and Diagnosing the System for Organizations. Jay Forrester10,11 created Systems Dynamics, in which complex systems are simulated, using key concepts of stocks, flows, feedback, and time delay. Even simple systems lead to nonlinearities, creating complex behavior. Peter Senge17 popularized many of these systems ideas in his best selling book The Fifth Discipline. He argues that organizations must become learning organizations by building knowledge of four disciplines: personal mastery, mental models, shared vision, and team learning. Systems thinking is the fifth discipline, which is required to integrate the other four disciplines.