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definition-System

Definition:

A System is any useful subset of the universe that we choose to put a boundary around, so we can focus on that part of the universe.

Alternative Names

Concept Number: *145
English Master: System [Planguage]
Synonyms, Variations & Acronyms: Object

Detailing

It can be conceptual or real.

Sometimes it can be useful to expand the boundaries of the System we look at, to better understand how what we are developing interacts with other systems.
At other times it can be useful to contract the boundaries of the System, so as not to get overwhelmed.

In Planguage, a System can be described fundamentally by a set of Attributes. The Attributes are of the following types:
Function: ‘what’ the System does
• Values: ‘how good’
• Development Resource: ‘at what cost’ (resource expenditure)
Solution: ‘by what means’

In addition, other factors describing various aspects of the System can be specified. These include:
Requirements
• dependencies
• risks
• priorities

All these specifications (the Attributes and the additional factors) are qualified by time, place and event conditions.


Illustrations

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Type

System [Planguage] *145: Systems Engineering Concept.


Examples

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Notes

1. There are specific Planguage parameters for capturing all the System information, including: Function, Performance, Resource, Design, Requirement, Dependency, Risk and Priority.

2. Svein Øvergaard, a Norwegian professor Client of mine said (about 1969) that he detested the word ‘system’ because it “had the precision of the word ‘thing’”. I have ever since then been careful using it and hope the Planguage definition limits the Scope somewhat.

3. Here are some Standard definitions of ‘system’:

Standard Definition [System, ISO 9000, 2000]:
“An object consisting of interrelated or interacting elements”
ISO 9000
Note, this ISO 9000 definition emphasizes the internal relationship or interaction of System elements. This has limited interest. The most central aspect of systems is how they are externally experienced and perceived by other systems, so the Planguage definition emphasizes the Attributes, and admits the possibility of all manner of description, including the ‘interacting elements’ – but chooses to emphasize real-world ‘interaction’ (between any one System and all others).

Standard Definition [System, EIA/IS-731.1, 1996 Interim Standard]:
“system: The aggregation of end products and enabling products that achieve a given purpose.”
Note in this EIA/IS-731.1 System definition, the Concept of ‘purpose’ comes in. However, lost is the possibility of multiple Stakeholders and multiple purposes through time.

Standard Definition [System, /IEC 15288, preliminary Version 2000]
“4.17 System
An object consisting of interrelated or interacting elements (ISO 9000: 2000).

Note In practice, a System is ‘in the eye of the beholder’ and the interpretation of its meaning is frequently clarified by the use of an associative noun, e.g. Product System, aircraft System. Alternatively, the word System may be substituted simply by a context-dependent synonym, e.g. Product, aircraft, though this may then obscure a System principles perspective.”
Note in this IEC 15288 definition, the Authors seem to see a problem with the Concept, but try to solve it by encouraging specific adjectives to describe it. They stick to the official Version [ISO] but do not mention Attributes or purposes. A hint about systems principles is given.

An integrated composite of people, products, and Processes that
provide a capability to satisfy a stated need or objective.
System
[MIL-STD 499B]
Note this MIL-STD 499B definition is unnecessarily narrow (It does not include the Planetary System or the molecular System. ☺ ) and unnecessarily broad (a people or Product or Process would be sufficiently narrow for many systems Engineering purposes). It is good that it mentions the capability to satisfy Requirements, but some systems have capabilities that satisfy nobody’s Requirements (like faults and side effects). Systems are as they are, whether we like it or not. We have to be able to understand and describe their Attributes realistically, like them or not.

4. When defining a System, it is important to decide the relationship between the System being observed and changed, and the System of the people (the project) bringing about any change. Numerous different relationships can exist. At one extreme, a project can be completely within the System being modified. At another extreme, a project might be developing a Product System to be sold into various, as yet unknown, target systems.


Keyed-Icons

[ --->O--> ]
or
--->(<mission tag>)--> “A System with Resources, Function and performance. Conditions are implied.”

Example:
-->(Mobile Phone)-->
In this Context the Mission tag, ‘Mobile Phone’ can serve as the reference name for the System, the Attributes of the System being implied by the arrows.


Drawn-Icons

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Attribute *003


History-of-Concept

2003: A System is any useful subset of the universe that we choose to specify. It can be conceptual or real.









This Concept entered by Kai.

Created by system. Last Modification: Friday 10 of January, 2020 20:19:54 CET by Admin (Kai).
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