! Defining Systems, and Systems Analysis; Ref: Cochin

"A SYSTEM is a collection of interconnected components in which there is a specified set of dynamic variables called 'inputs' (or excitations) and a dependent set called 'outputs' (or responses).

..A system can be expressed as a collection of collections.

..at the SUBSYSTEM level, the collection of interconnected components and their behaviours can be thought of as 'events'. ... a large system can be considered as a collection of interconnected events, where each event consists of a collection of interconnected components."

Systems may be classified as follows:

'Independent', the events have no effect on one another and may be studied independently.

'Cascaded', the events are arranged unilaterally in a sequential process, they may be studied one at a time and the output from the proceeding will determine the input to the succeeding.

'Coupled', the events mutually affect each other, they cannot be studied one at a time but must be studied simultaneously. There will be at least one closed flow of output-input loop that will pass through one or more events.

For most analysis and study systems are considered CLOSED. A carefully designated boundary is an essential part with things inside considered internal or endogenous and those outside exogenous or external. Accounting, imposes a closed approach consisting of a defined boundary and finite time intervals to the systems to which it is applied. An accounting type of approach is usually used to make a system amenable to analysis.

Real systems are generally OPEN and may have fuzzy boundaries.

Spectrum of System Study Methodology:

REAL WORLD

1.     Operational Exercise

2.     Gaming

3.     Simulation

4.     Analytical Model

5.     Committee Review

6.     Individual Review

read down
Increasing
Cost
and Realism

read down
Potentially
Increasing
Speed of Analysis
and Abstraction

 

^ [NUNET] * [Hall's Matrix of Activities for Systems Study] * [ Problem Solving Techniques ] *

[ O.R. Operations Research ] * [ Synopsis of Model Types ]  *[NUNET description ] * [ TOPICS included ] *

[Introductions to various TOPICS ] * [ Tools page] * [Search Index * Files]

 End to date: 060210, ams