Model-Based System Architecture, 2nd Edition

4Systems, Systems of Systems, and Cyber-Physical Systems*

4.1 Definition of “System”

The term “system” has many, slightly varying definitions, what is not surprising since its usage is very broad. The term origin traces back to ancient Greek times. It originates from the Greek “sustēma” [196]. The statement “the whole is something over and above its parts, and not just the sum of them all” is attributed to the Greek philosopher and polymath Aristotle. In the nineteenth century, the notion of “system” became important with the works in the fields of thermodynamics by Nicolas Carnot and Rudolf Clausius. The General Systems Theory by Ludwig von Bertalanffy relied on a definition of “system.” Subsequently, the term was used in psychology, operations research, and systems engineering [58, 265].

The online browsing platform of ISO [119] provides 140+ hits when searching the exact term “system” in the area “Terms & Definitions.” We focus hereinafter on three definitions from the systems engineering community.

The standard ISO/IEC/IEEE 15288:2015 [115] defines “system” as a combination of interacting elements which are organized to achieve one or more stated purposes.

The INCOSE Systems Engineering Handbook [265] appends the definition of the standard ISO/IEC/IEEE 15288:2015 with:

An integrated set of elements, subsystems, or assemblies that accomplish a defined objective.

In the INCOSE brochure “Systems Engineering and System Definitions” [227], the definition of “system” had been ...