Systems Theory and Modelling

geographertonguesΤεχνίτη Νοημοσύνη και Ρομποτική

30 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

61 εμφανίσεις

Systems Theory

and Modelling

© David O’Sullivan, NUI Galway

Seminars

Introduction

Defining Innovation

Innovation Process

Understanding Goals

Defining Objectives

Managing Indicators

Systems Theory and Modelling

Creativity

and Idea
Generation

Managing Project Portfolios

Leading Innovation Teams

Managing Results and Knowledge


© David O’Sullivan, NUI Galway

This Lecture


Open Systems


General Systems Theory (GST)


GST Traits


System Classification


Systems Analysis and Modelling


Activity Modelling (IDEFo)



© David O’Sullivan, NUI Galway

Reduction vs. Systems


1950’s the main approach to
understanding was ‘reductionism’


divide something into its parts


Ludwig von Bertalnffy proposed
systems thinking


discover how
something interacts with its
environment

© David O’Sullivan, NUI Galway

Open Systems


All living and many non
-
living things
are open systems


Systems theory gives us a way to ‘think
about’ open systems


Systems theory lays the foundation for
the analysis and modelling of systems


Systems theory provides an analytical
framework for comprehending dynamic
interrelated operating systems

© David O’Sullivan, NUI Galway

Open System

Sense

Response

ENVIRONMENT

OPEN

SYSTEM

© David O’Sullivan, NUI Galway

University


Open System

UNIVERSITY

Policy

Approved Funding

Industry Needs

Students

Funding Requests

New Knowledge

Graduates

© David O’Sullivan, NUI Galway

Systems Thinking


holistic approach to problem
solving


reflecting on how the organisation
relates to its business environment
and


how factors in the environment
can affect the organisation

© David O’Sullivan, NUI Galway

Definition of ‘System’

“... an identifiable, complex dynamic
entity composed of discernibly
different parts or subsystems that
are interrelated to and
interdependent on each other and
the whole entity with an overall
capability to maintain stability and
to adapt behaviour in response to
external influences” [Webster’s]

© David O’Sullivan, NUI Galway

General Systems Theory


Science of understanding open systems
theory


GST provides a framework to study open
systems


GST is not too general nor too specific

© David O’Sullivan, NUI Galway

Boulding’s Explanation

“Somewhere … between the specific
that has no meaning and the
general that has no content there
must be, for each purpose and at
each level of abstraction, an
optimum degree of generality”

© David O’Sullivan, NUI Galway

Beckett’s explanation

"The trust of general systems .. is to
draw attention to the study of
relationships of parts to one
another within the wholes”

© David O’Sullivan, NUI Galway

GST Traits


Systems …


are Goal Seeking


are Holistic


have Hierarchy


have Inputs and Outputs


transform inputs into outputs


consume and/or create Energy


are affected by Entropy


have Equifinality


have Feedback

© David O’Sullivan, NUI Galway

Goal Seeking




All open systems must have goals


There are two types


Inner directed goals


Outer directed goals


Design strategies are typically “outer
directed” goals


Maintenance strategies are an “inner
directed” goal

© David O’Sullivan, NUI Galway

Holistic

SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
Boundry

Fredrick Hagel (1770
-
1831)


The whole is more than the
sum of the parts


The whole determines the sum
of the parts


The parts cannot be
understood if considered in
isolation from the whole


The parts are dynamically
interrelated and
interdependent

© David O’Sullivan, NUI Galway

Hierarchical

WHOLE
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SUB
SYSTEM
SYSTEMS
MORE GENERAL
MORE DETAIL
PLANT LEVEL
DEPARTMENT LEVEL
CELL LEVEL
PROCESS LEVEL
WORKSTATI ON LEVEL
© David O’Sullivan, NUI Galway

Transform Inputs into Outputs

TRANSFORM
INPUTS TO
OUTPUTS
TRANSFORM
INPUTS TO
OUTPUTS
ERROR
FEEDBACK
STATUS FEEDBACK
OUTPUT
INPUT
INPUT
OUTPUT
INPUT
OUTPUT
INPUT
© David O’Sullivan, NUI Galway

Entropy


A measure of the amount of disorder in
a system


Everything disintegrates over time


Negative entropy or centropy


Effects of entropy are offset by the
system transforming itself continuously


Maintain order through such things as
repairs, maintenance and possibly
growing by importing ‘energy’

© David O’Sullivan, NUI Galway

Energy, Equifinality and Feedback


Systems create/consume energy


Physical


Emotional


Equifinality is the ability for systems to
achieve goals in a number of ways


This flexibility allows systems avoid the
effects of entropy


Systems have feedback
-

feedback can
allow a system to change its direction

© David O’Sullivan, NUI Galway

System Classification


Checkland's classification


Natural Systems (ecological
systems, human beings)


Physically Designed Systems
(bridges, machines)


Abstract Design Systems
(Languages, Mathematics)


Human Activity Systems
(Politics, Banking)


Transcendental Systems
(Beyond knowledge or
comprehension)


Boulding’s Classification

Transcendental
Social Oganisation
Human
Animal
Genetic-societ al
Open System
Cybernetics
Clockworks
Frameworks
1
2
3
4
5
6
7
8
9
© David O’Sullivan, NUI Galway

Boulding’s Classification


Frameworks


static structures (e.g. camshaft, skeleton, formal company organisations, rock)


Clockworks


timing mechanisms (e.g. self winding clocks)


Cybernetics


elementary closed systems with feedback (e.g. thermostats)


Open system


elementary forms of life interact with their environment in order to change their
behaviour


Genetic
-
societal systems


exchange information with other subsystems


Animal system


mobility, self
-
awareness, and goal orientation
-
highly complex


Human system


intelligence gives the human system the ability to think about the future, its
goals, and how to reach them.


Social organisation


organisations which have their own combined goals, needs


Transcendental,


all other systems not yet comprehended

© David O’Sullivan, NUI Galway

Conclusions


Views of GST are universal


GST combats ‘isolationist’ tendencies among
engineers, systems analysts, business
analysts, IT specialists, etc. etc.


GST offers a framework for understanding all
systems


Benefits of GST to design of systems are
significant


Theory of GST lays at the foundation of much
new thinking in
-

including ‘Learning
Organisations’, ‘Structured Analysis’,
‘Sociotechnical Design’ and ‘Strategic Planning’

© David O’Sullivan, NUI Galway

5 minute break!


Open Systems


General Systems Theory (GST)


GST Traits


System Classification



Systems Analysis and Modelling


Activity Modelling (IDEFo)

Systems Analysis

and Modelling

© David O’Sullivan, NUI Galway

Modelling


Represent
existing

and
future

systems


Models are in
-
complete


Various models represent different
perspectives and levels of abstraction


Modelling techniques should be selected
to enhance communications between
designers and users

© David O’Sullivan, NUI Galway

Perspectives

Managing Director

Manufacturing

Engineer

Software

Engineer

Supervisor

Manufacturing

Manager

Accountant

© David O’Sullivan, NUI Galway

Techniques

© David O’Sullivan, NUI Galway

IDEFo


Background


Activity Modelling


Cell Modelling


Hierarchical Decomposition


Principles of IDEFo


IDEFo Approach

© David O’Sullivan, NUI Galway

Background


IDEFo is an
activity

or
process

modelling
technique


Developed through US AirForce R&D


Basic idea: Adopt a common language for all
designers


Original ideas by Ross and his SADT technique


Sister languages


IDEF1x used for data structure modelling


IDEF2 used for dynamic modelling (simulation)


Etc.


http://www.idef.com


© David O’Sullivan, NUI Galway

Cell Modelling

© David O’Sullivan, NUI Galway

Cell Modelling

© David O’Sullivan, NUI Galway

Cell Modelling

© David O’Sullivan, NUI Galway

Hierarchical Decomposition

© David O’Sullivan, NUI Galway

Arrows

© David O’Sullivan, NUI Galway

ICOM Codes

© David O’Sullivan, NUI Galway

Boundary Arrow Correspondence

© David O’Sullivan, NUI Galway

Tunnelled Arrows

© David O’Sullivan, NUI Galway

Modelling Demonstration


Choose an activity!


Choose purpose and viewpoint!


Creating the A
-
0 diagram


Creating the A0 diagram


Creating the A
-
1 diagram

© David O’Sullivan, NUI Galway

Node Index and Tree


A0 Manufacture Product


A1 Plan For Manufacture


A11 Identify Manufacturing Methods


A12 Estimate Requirements, Time, Cost to


A13 Develop Production Plans


A14 Develop Support Activities Plan


A2 Make and Administer Schedules and Budgets


A21 Develop Master Schedule


A22 Develop Coordinating Schedule


A23 Estimate Costs & Make Budgets


A24 Monitor Performance To Schedule & Budget


A3 Plan Production


© David O’Sullivan, NUI Galway

Principles of IDEFo


Cell Modelling Graphic Representation


Boxes
-
and
-
arrows show graphically all activities in a
system


Conciseness


Two dimensional ‘structured’ diagrams and text provide
concise detail


Communication


Simple boxes and arrows, limitation of detail, structured
presentation of information


Rigor and Precision


Methodology


Step
-
by
-
step approach


Organisation versus Function


Separation of organisation from function

© David O’Sullivan, NUI Galway

Rigor and Precision


Detail exposition control (no more than six boxes)


Limited context (no omissions or unnecessary detail)


Diagram interface inter
-
connectivity


Data structure connectivity (through parenthesis)


Uniqueness of labels and titles


Syntax rules for graphics


Inputs are separate from controls


Data arrow labelling requirements


Minimum control of function


Purpose and viewpoint

© David O’Sullivan, NUI Galway

IDEFo Methodology


Select a viewpoint and purpose


Limit the subject matter


Create a top level diagram (A
-
0
, one box only)


Create a context diagram (A
-
1
, if necessary)


Create AO diagram (A0, two to six boxes)


Create subsequent diagrams, text and glossary


Review material and check for purpose and viewpoint


Additional pointers


Avoid trivial activities and flows


Limit necessary detail at each level


Group related arrows and activities to simplify detail


Be clear, precise and consistent


Think control and not flow


Delay the addition of detail


If in doubt incoming flows should be controls


Annotate as you develop each diagram

© David O’Sullivan, NUI Galway

Sample


See course notes on 'Enterprise
Modelling'


© David O’Sullivan, NUI Galway

Summary


Open Systems


General Systems Theory (GST)


GST Traits


System Classification


Systems Analysis and Modelling


Activity Modelling (IDEFo)



© David O’Sullivan, NUI Galway

Online Assignment


Develop an IDEFo model for
your
organisation


Produce A
-
0, A0, and A
-
1
diagrams


Graphics plus Description Text


Upload model into ‘Models’ web
part