1 On the Nature of Systems James N Martin Systems Engineering Conference SEDC 2012 at GMU...

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On the Nature of Systems

On the Nature of Systems

James N MartinSystems Engineering Conference

SEDC 2012 at GMU

Washington, DC

15 May 2012

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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.”

“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

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Thing

System as a “Point of View”

Point of View

Image

Observer

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Two Observers Two SystemsTwo Observers Two Systems

Thing

Observers

Point of View

Image

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Some Recent History

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

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

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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

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A Common (Mis)Perception

System = Sum of Parts

That We Design & Build

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System Parts

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Parts – Also Known As…

• Subsystems

• Elements

• Products

• Devices

• Subassemblies

• Components

• Items

• Units

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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

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

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What Types of Parts Constitute a System?

Hardware and Software ??

Hardware and Software and People ??

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Types of System PartsTypes of System Parts

PATENT

BASICPART TYPES

BASICPART TYPES

HARDWARE SOFTWARE PERSONNEL FACILITIES

DATA MATERIALS SERVICES TECHNIQUES

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More Than Just Parts…

System = Sum of Parts

+ Interactions

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How many ways to Interact ?

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Which is the best way to Interact ?

??

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Beyond Interactions…

System = Sum of Parts

+ Interactions

+ Context

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Context 1

PARTPARTPART

PART

Context 2

PARTPARTPART

PART

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Beyond Context…

System = Sum of Parts

+ Interactions + Context

+ Actions

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Camera Actions

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Action Diagrams

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Context A

Action in Different Contexts

Action1

Action2

Context B

Action1

Action3

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Beyond Actions…

System = Sum of Parts

+ Interactions + Context

+ Actions + Relationships

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Relationship Types

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

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

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

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Entity-Relationship Pairs

Entity A

Entity B

Related to

Rain

Wet Ground

Causes

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Relationship Examples

Balls

Box

Inside

Road

Building

Brings traffic toand from

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Observing System Relationships

Observing System

Data Handling Systemprovides

data to

Userprovides info to

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Observing System Relationships

Observing System

Data Handling Systemprovides

data to

Userprovides info to

is type of

Stake-holder

has

Stakeholder Requirement

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Observing System Relationships

Observing System

Data Handling System

Environmental Phenomenon

provides data to

Basic Service Requirement

< drives

Userprovides info to

is type of

Stake-holder

has

Stakeholder Requirement

< drives< drives

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Observing System Relationships

Observing System

Data Handling System

Human

Environmental Phenomenon

Environmental Parameter

Sensing Element

Sensor

measures

is a

contains

characterizes

provides data to

Basic Service Requirement

< drives

Userprovides info to

is type of

Stake-holder

has

Stakeholder Requirement

< drives< drives

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Observing System Relationships

Observing System

Data Handling System

Human

Environmental Phenomenon

Environmental Parameter

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

Basic Service Requirement

< drives

provides data directly to

Userprovides info to

is type of

Stake-holder

has

situated on

Stakeholder Requirement

< drives< drives

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Observing System Relationships

Larger System

Observing System

Data Handling System

Human

Environmental Phenomenon

Environmental Parameter

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

Basic Service Requirement

< drives

provides data directly to

Userprovides info to

is type of

Stake-holder

has

Operator operated by

situated on

Support

supported by

Owner

owned by

Stakeholder Requirement

< drives< drives

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Observing System Relationships

Larger System

Observing System

Data Handling System

Human

Environmental Phenomenon

Environmental Parameter

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

Basic Service Requirement

< drives

provides data directly to

Userprovides info to

is type of

Stake-holder

has

Operator operated by

situated on

Support

supported by

Owner

owned by

Stakeholder Requirement

< drives< drives

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System = Sum of Parts

+ Interactions + Context

+ Actions + Relationships

+ Destiny

And Finally…

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Destiny Impact

Purpose

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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

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Thing

Systems are “Imaginary”

Point of View

Observer

Image

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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.”

“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

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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