1 on the various conceptualizations of systems …and their impact on the practice of systems...

1

On the Various Conceptualizations of Systems

…and Their Impact on the Practice of Systems Engineering

On the Various Conceptualizations of Systems

…and Their Impact on the Practice of Systems Engineering

2008 INCOSE Symposium

James N MartinTimothy L J Ferris

© 2008 The Aerospace Corporation & Timothy L J Ferris

2

Systems Thinking

“A system is a way of looking at the world.”

“… a system, any system, is the point of view of one or several observers.”



Gerald M. Weinberg (1975),An Introduction to General Systems Thinking

3

Thing

System as a “Point of View”

Point of View

Image

Observer

4

Two Observers Two SystemsTwo Observers Two Systems

Thing

Observers

Point of View

Image

5

Some Recent History

• The Solar System (2005) The Sun plus 9 Planets

• The Solar System (2006) The Sun plus 8 Planets

6

Our Choice…• The things we “put” into our System

– Are things of our own Choosing– Are there for the purpose of Understanding– Are not pre-determined by some magical “Rules of

Inclusion”

• We must choose Carefully– A wrong choice could lead to incorrect Understanding– We often don’t know a priori what is the best

Rule of Inclusion to use– May need to experiment with different possible

System boundaries & configurations

13

A Common (Mis)Perception

System = Sum of Parts

That We Design & Build

14

System Parts

15

Parts – Also Known As…

• Subsystems

• Elements

• Products

• Devices

• Subassemblies

• Components

• Items

• Units

16

What are the Parts of this System ?

• Camera Lens Assembly• Flash Device• Electronic Circuit• User Interface Unit

• Carrying Case• Shipping Container• Instructions• Technique for Holding• Extra batteries• Photo Printer• Patents

17

We need to Imagine more than just the things we build…

18

What Types of Parts Constitute a System?

Hardware and Software ??

Hardware and Software and People ??

19

Types of System PartsTypes of System Parts

PATENT

BASICPART TYPES

BASICPART TYPES

HARDWARE SOFTWARE PERSONNEL FACILITIES

DATA MATERIALS SERVICES TECHNIQUES

20

More Than Just Parts…


+ Interactions

21

How many ways to Interact ?

22

Which is the best way to Interact ?

??

23

Beyond Interactions…


+ Interactions

+ Context

24

Context 1

PARTPARTPART

PART

Context 2

PARTPARTPART

PART

25

Beyond Context…


+ Interactions + Context

+ Actions

26

Camera Actions

27

Action Diagrams

28

Context A

Action in Different Contexts

Action1

Action2

Context B

Action1

Action3

29

Beyond Actions…



+ Actions + Relationships

30

Relationship Types

• Interpersonal– Family, Friends, Social, Organizational, …

• Mathematical– Equality, Order, Topological, Functionality, …

• Cause-Effect– Event-Driven, Probabilistic, …

• Physical Properties– Forces, Fields, Chemical effects, …

31

Entity-Relationship Pairs

Entity A

Entity B

Related to

Rain

Wet Ground

Causes

32

Relationship Examples

Balls

Box

Inside

Road

Building

Brings traffic toand from

33

Observing System Relationships

Observing System

Data Handling Systemprovides

data to

Userprovides info to

34


Observing System

Data Handling Systemprovides

data to


is type of

Stake-holder

has

Stakeholder Requirement

35


Observing System

Data Handling System

Environmental Phenomenon

provides data to

Basic Service Requirement

< drives


is type of

Stake-holder

has


< drives< drives

36


Observing System


Human


Environmental Parameter

Sensing Element

Sensor

measures

is a

contains

characterizes

provides data to


< drives


is type of

Stake-holder

has


< drives< drives

37


Observing System


Human



Sensing Element

Sensor

Platform / Station

measures

is a

contains

characterizes

provides data to

Location

located at

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives

provides data directly to


is type of

Stake-holder

has

situated on


< drives< drives

38


Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to

Observation Control System

is controlled by

Location

located at

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has

Operator operated by

situated on

Support

supported by

Owner

owned by


< drives< drives

39


Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to


is controlled by

Location

located at

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has


situated on

Support

supported by

Owner

owned by


< drives< drives

40



+ Actions + Relationships

+ Destiny

And Finally…

41

Destiny Impact

Purpose

42

PICARD Theory of Systems

Parts

Interactions

Context

Actions

Relationships

Destiny

Holistic Image ofSystem =

From the Point of View of an ObserverFrom the Point of View of an Observer

43

Thing

Systems are “Imaginary”

Point of View

Observer

Image

4444

System – Seen by Operator

Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to


is controlled by

Location

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has


situated on

Support

supported by

Owner

owned by


< drives< drives

4545

System – Seen by User

Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to


is controlled by

Location

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has


situated on

Support

supported by

Owner

owned by


< drives< drives

4646

System – Seen by Developer

Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to


is controlled by

Location

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has


situated on

Support

supported by

Owner

owned by


< drives< drives

IF

IF IF IF

IF

IF

IF

IF

4747

System – Seen by GEOSS

Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to


is controlled by

Location

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has


situated on

Support

supported by

Owner

owned by


< drives< drives

4848

System – Seen by NOAA Director

Larger System

Observing System


Human



Sensing Element

Sensor

Platform / Station

part of

measures

is a

contains

characterizes

provides data to


is controlled by

Location

MobileFixed

is

Space

Air

Ground

Ocean

Space

Air

Ground

Ocean


< drives



is type of

Stake-holder

has


situated on

Support

supported by

Owner

owned by


< drives< drives

49

Systems Thinking





Gerald M. Weinberg (1975),An Introduction to General Systems Thinking

50

Postscript

All models are wrong, some are useful– George Box

All systems are imaginary, some are useful– James Martin

Models can be used to facilitate the imaginationModels can be used to

facilitate the imagination

1 on the various conceptualizations of systems …and their impact on the practice of systems...

Documents

system parts slide

parts system

context system

interactions system

context slide

thing system

solar system

build slide