Editing Systems engineering (section)

===Evolution to a broader scope===
The use of the term "systems engineer" has evolved over time to embrace a wider, more holistic concept of "systems" and of engineering processes. This evolution of the definition has been a subject of ongoing controversy,<ref>{{cite conference|title=The Case for Evolving Systems Engineering as a Field within Engineering Systems|first1=Donna|last1=Rhodes|first2=Daniel|last2=Hastings|conference=MIT Engineering Systems Symposium|date=March 2004|citeseerx=10.1.1.86.7496}}</ref> and the term continues to apply to both the narrower and a broader scope.

Traditional systems engineering was seen as a branch of engineering in the classical sense, that is, as applied only to physical systems, such as spacecraft and aircraft. More recently, systems engineering has evolved to take on a broader meaning especially when humans were seen as an essential component of a system. [[Peter Checkland]], for example, captures the broader meaning of systems engineering by stating that 'engineering' "can be read in its general sense; you can engineer a meeting or a political agreement."<ref name="Checkland">{{cite book|last=Checkland|first=Peter|editor-last=Pyster|editor-first=Authur|title=Systems Thinking, Systems Practice|publisher=John Wiley & Sons|date=1999}}</ref>{{Rp|10}}

Consistent with the broader scope of systems engineering, the [[Systems Engineering Body of Knowledge]] (SEBoK)<ref>{{cite book|last=Checkland|first=Peter|editor-last=Pyster|editor-first=Authur|title=Systems Thinking, Systems Practice|publisher=John Wiley & Sons|date=1999}} 2012. Systems Engineering Body of Knowledge. 1.0 ed: Stephens Institute and the Naval Postgraduate School.</ref> has defined three types of systems engineering:
* Product Systems Engineering (PSE) is the traditional systems engineering focused on the design of physical systems consisting of hardware and software.
* Enterprise Systems Engineering (ESE) pertains to the view of enterprises, that is, organizations or combinations of organizations, as systems.
* Service Systems Engineering (SSE) has to do with the engineering of service systems. Checkland defines a service system as a system which is conceived as serving another system.<ref name="Checkland"/> Most civil infrastructure systems are service systems.