This is a formalised way of handling complex technical projects.
The main professional body for systems engineering, INCOSE (The International Council for Systems Engineering) defines system engineering as "Systems Engineering is an interdisciplinary approach and means to enable the realisation 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."
The origins of system engineering are not exactly clear. The Americans tend to give the credit for inventing systems engineering to Bell Labs in the 1940's, and they are reputed to be the first organisation that used the term. In Britain we like to give the credit to a British multi-disciplined team formed in 1937 to analyze the air defence system. However perhaps we should all acknowledge Aristotle (384-322BC) as the founding father of the principle behind systems engineering when he said "The whole is more than the sum of the parts".
Whatever its origins, since WW2 it has gradually become the leading methodology for organising large and complex technical projects; the NASA space programme being an example. System Engineering principles, including the 'System Vee' (see below) were used by the major automotive companies, such as Ford & GM, when they were developing their Stage-Gate® processes in the 1980s.
A system is a an 'organized whole' (from the Greek 'systema'), that is composed of separate parts or sub-systems, that are arranged in a hierarchy and interact with each other to meet a purpose.
System engineering is concerned with the life cycle of the system from inception to disposal. It takes a top-down approach, so as to view the system as a whole. To be successful the requirements for the system have to be known and understood and an inter-disciplinary approach has to be taken.
To do this a couple of key concepts underpin Systems Engineering
The Systems Engineering Management Plan (SEMP)
This links in to the overall Project Management Plan, but it covers the technical aspects in more detail. It is the top level technical plan for identifying and integrating all the activities across all the engineering disciplines. (Though each of these may have their own even more detailed plan, they should always be in step with the SEMP.) It is usually the responsibility of the chief engineer, or equivalent.
The System Vee Model
This describes the process of definition of the system from the highest down to the lowest level down the left-hand side of the 'Vee' and the process of test, verification and validation up the right-hand side of the Vee.
By the way, Verification means checking that the system or sub-system meats the system requirements. Validation means checking that it meets the user requirements.
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