International Encyclopedia of Systems and Cybernetics

An interdiscipline concerned with the interactions of equipment in larger and larger complex systems. (adapted from R.L. ACKOFF, 1972, p.4).

L.von BERTALANFFY gives the following definition, more explicit: "Scientific planning, design, evaluation and construction of man-machine systems" (1962, p.3).

A more precise definition is given by JENKINS: "The science of designing complex systems in their totality to ensure that the component subsystems making up the system are designed, fitted together, checked and operated in the most efficient way" (as quoted by M.C. JACKSON, 1992, p. 74).

ACKOFF states: "In equipment incorporating automatic controls, the systems approach is almost inescapable." and "The engineer of course, can no more ignore the human operator than the personal psychologist can ignore the machine to be operated ".

J. WARFIELD, quoting A.D. HALL III, describes as follows the "Seven phases of Systems Engineering" (in time):

"1. Program planning… in which those programs to be pursued are defined and selected

2. Project planning… in which the specific projects to be carried out under a program are identified and budgeted

3. System development… in which the projects necessary to develop the system are carried out and production plans are made

4. Production… in which the systems elements and the total system are produced, and plans are completed for its operation

5. Installation… in which the system is installed and programs are carried out for its operation

6. Operation… in which the system is in operation serving its intended use, and plans are made for its eventual replacement or retirement

7. Retirement… in which the system is withdrawn from use, to be replaced by a new system, or is modified significantly" (WARFIELD, 1989, p.169).

The same author also distinguishes "Seven steps of Systems Engineering" in the "Logic dimension":

"1. Problem definition

2. Value system design

3. Systems synthesis

4. Systems analysis

5. Optimization of each alternative

6. Decision making

7. Planning for action to implement the nex1 phase" (p.171)

All these phases and steps are fully described in quoted reference.

It would seem, from recent man-made disasters (Chernobyl, the Aral Sea, etc….) that ACKOFF's "complex system" should be taken in a still larger sense, incorporating planners, financists, ecologists and many more so-called stakeholders (according to each specific situation) into global participative design, which would obviously be quite slower, but also more secure…

In effect Systems Engineering is still frequently concerned only or mainly with the machine part of the man-machine system. Also and particularly both points 7s, about "Retirement or replacement" and "Planning for implementing the next phase" are in most cases forgotten… or even brushed under the carpet.

See: "Interdisciplinarity"; "Multidisciplinarity" and "Transdisciplinarity"

As a result, W. GASPARSKI et al. state: "Initially it was expected that systems engineering treated as normative methodology of design of complex objects would become a paradigm of the rational theory of design. However, those expectations have not been fulfilled. Although systems engineering helped modernize the practical designing process, yet it contributed very little to the new knowledge of design. Its explanatory capacity proved insufficient to form the design paradigm" (1995, p.17).

The crux of the matter seems to be that systems engineering – at least when applied to the design of man-machine systems, its main general use – does not include sufficiently the psychological and social factors in these human activity systems, described by P. CHECKLAND (1972, p.72).