Traditional engineering disciplines (e.g. electrical, mechanical, civil, chemical) are concerned with transforming physical entities from one form into another; they follow physical laws or properties and relations. System Engineering and Software Engineering are engineering disciplines that do not have a core theory, physical law or properties; these engineering disciplines deal with the work activities to develop a system or software.
System Engineering
In the United States, during the Second World War, the postwar period and the beginning of the Cold War, there was a need to develop techniques based on General Systems Theory to create great defense systems. Engineers, scientists and managers developed techniques that have become known by (1) Systems Engineering for the design and development of systems, (2) Operational Research to analyze the Armament Systems and (3) Systems Analysis to compare and evaluate projects. These techniques have been developed because the systems that were being created had a level of complexity that could not be fully understood with the knowledge that was taught by the classical schools of Engineering and Management (Hughes, 2005).
Since its formalization, Systems Engineering has been an activity based on practice; it is considered more a method than a discipline founded in books and formalisms. Unlike the traditional disciplines of engineering, Systems Engineering does not follow a set of fundamental phenomena based on physical properties and relations; instead, it is associated to knowledge to orchestrate these physical properties and relations, to deal with system emergent properties.
Hitchins (2008) argues that Systems Engineering view systems as dynamic and open, potentially adaptable to other systems in the same environment, and capable of showing emerging properties, capabilities and behaviors. This approach emphasizes the dynamic interaction not only among the parts of the system, but also among a system and systems external to it. The emphasis is on performance, features, functionality, and dynamic processes. Hitchins also argues that when engineers deal with simple systems, the results of classical engineering approach or Systems Engineering approach may be similar, but the result in complex systems is different.
Kossiakoff & Sweet (2003), Sydenham (2004), INCOSE (2006), and Wasson (2006) define System Engineering using significant words, such as: interdisciplinary, iterative, socio-technical, and whole. However, these words refer to how System Engineering must be done; they are not a term definition. The authors of this work use the definition given by Hitchins (2008): “Systems engineering is the art and science of creating whole solutions to complex problems.”