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Unsurprising as this may
seem INCOSE (the International Council on Systems
Engineering) define Systems Engineering as "the
discipline of developing systems products or
processes based on a total systems perspective and
utilizing a systems engineering approach." It was
conceived of, and introduced by, the US Government
to counteract the difficulties encountered in the
engineering of increasingly large, complex, and
inter-disciplinary systems. Systems Engineering has
evolved to aid in the design of other types of
systems, including small systems.
Some Principles of
Systems Engineering
Systems Engineering has as its basis a few simple
but powerful principles. These are outlined below:
Systems Engineering Principles
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Iterative Top-Down
Design This means that a complex system is
designed by breaking it down into its component
sub-systems and then repeating the process on
each sub-system until all that remains are
easily designable components.
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Bottom-Up
Integration Large systems are built by taking
the lowest level components and putting them
together one level at a time. As each level of
integration is completed it is tested to make
sure it works. Bottom-up integration is top-down
design in reverse.
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System Life Cycle A
life cycle is the progression of a system from
inception (NPIP Phase 1), to implementation (NPIP
Phases 2 & 3), operation (NPIP Phases 4 & 5),
maintenance and eventually its shutdown,
disassembly and disposal (not covered by NPIP
but included in item 9 of the GPS Environmental
Policy Statement).
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User Perspective
Systems Engineering attempts to build systems
that take into account what the user wants,
needs, prefers, is happy with and can use.
The principles of
Systems Engineering are very powerful and can be
used in a very wide variety of different situations
where a methodical and holistic approach is needed.
Defining Terms
Systems Engineering Terms
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Architecting The
process by which a system is created, designed
and built.
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Complexity The
degree to which a system has a design or
implementation that is difficult to design or
verify.
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Design The process
of defining the architecture, components,
interfaces and other characteristics of a system
or component. The result of the process.
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Development The
process of translating a design into hardware
and/or software components.
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Heuristics Empirical
rules of thumb derived from experience and
judgement, useful for attacking problems too
complex to be solved by analytical techniques
alone.
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Requirements
Statements which identify the essential needs
for a system in order for it to have value and
utility.
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Specification A
document that describes technical requirements
and verification procedures for items, materials
and services.
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System An integrated
composite of people, products and processes that
provide a capability to satisfy a stated need or
objective.
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System Architecture
The underlying structure of a system.
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