Evolution of Complex Systems Lecture 2: Definition of Systems Peter Andras / Bruce Charlton [email protected]@ncl.ac.uk.

Evolution of Evolution of Complex Complex SystemsSystems

Lecture 2: Definition of Lecture 2: Definition of SystemsSystems

Peter Andras / Bruce CharltonPeter Andras / Bruce Charlton

[email protected]@ncl.ac.uk

[email protected]@ncl.ac.uk

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LiteratureLiterature

Charlton, BG and Andras, P (2003). Charlton, BG and Andras, P (2003). The Modernization Imperative (The Modernization Imperative (http://www.hedweb.com/bgcharltohttp://www.hedweb.com/bgcharlton/modernization-imperative.htmln/modernization-imperative.html))

Luhmann, N (1995). Social Luhmann, N (1995). Social SystemsSystems

Miller, JG (1978). Living SystemsMiller, JG (1978). Living Systems

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ObjectivesObjectives

Examples of systemsExamples of systems Fundamental concepts:Fundamental concepts:

CommunicationCommunication EnvironmentEnvironment Action and perceptionAction and perception ReferenceReference Main function of systemsMain function of systems

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The cellThe cell

Complex system of many cellular organellesComplex system of many cellular organelles System of interacting proteinsSystem of interacting proteins

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MedusaMedusa

Filter feeder organism with tissues Filter feeder organism with tissues and organsand organs

(www.junglewalk.com)

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MouseMouse

Complex organism with many Complex organism with many tissues and organstissues and organs

(www.junglewalk.com)

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The nervous systemThe nervous system

Complex network Complex network of specialized of specialized cells (neurons) cells (neurons) dealing with the dealing with the information information processing of an processing of an organismorganism

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The conscious selfThe conscious self

A system communicating about A system communicating about the identity of the selfthe identity of the self

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Ant colonyAnt colony

Many communicating individual Many communicating individual organisms form a complex system organisms form a complex system togethertogether

(research.amnh.org/entomology)

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Political systemPolitical system

The system of human communications The system of human communications about how to distribute and use power about how to distribute and use power within the societywithin the society

(depthome.sunysuffolk.edu)(www.janes.com)

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The Windows OSThe Windows OS

Large system of many software Large system of many software processes (programs) that processes (programs) that communicate with each othercommunicate with each other

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Communication – the Communication – the conceptconcept

Sender Signal Receiver

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Sender and receiverSender and receiver

Sender and receiver: Sender and receiver: communication unitscommunication units that can that can send and receive signalssend and receive signals

Their key feature is that they can Their key feature is that they can communicate with each othercommunicate with each other

We ignore their inner structureWe ignore their inner structure E.g., two mobile phonesE.g., two mobile phones

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SignalSignal

Signal = a behaviour or a state of Signal = a behaviour or a state of the sender communication unitthe sender communication unit

E.g., a set of modulated E.g., a set of modulated electromagnetic waves generated electromagnetic waves generated by a mobile phoneby a mobile phone

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Signal transmissionSignal transmission

Signal transmission:Signal transmission: Signal generation by the senderSignal generation by the sender Signal reception by the receiverSignal reception by the receiver It may involve signal deterioration It may involve signal deterioration

due to the transmission mediadue to the transmission media E.g., communication through E.g., communication through

mobile phonesmobile phones

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CommunicationCommunication

Sender unit:

Signals generated

Receiver unit:

Signals received

Communication:

Signals transmitted

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Communication – issues not Communication – issues not yet discussedyet discussed

Meaning of communicationMeaning of communication Structure of communication: e.g., Structure of communication: e.g.,

sequence or pattern of signalssequence or pattern of signals

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Communication systems – Communication systems – 1 1

We consider We consider systemssystems as as communication systemscommunication systems: set of : set of communication units that exchange communication units that exchange communications, the system being the communications, the system being the set of these communicationsset of these communications

All systems discussed can be seen as All systems discussed can be seen as communication systemscommunication systems

E.g., nervous system, ant colony, E.g., nervous system, ant colony, Windows OSWindows OS

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Communication systems – Communication systems – 2 2

Communication system

Communication units

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The cell’s environmentThe cell’s environment

(cti.itc.virginia.edu)

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Outside of a systemOutside of a system

Communications between Communications between communication units, which are communication units, which are not part of the systemnot part of the system

E.g., mobile phones and satellite E.g., mobile phones and satellite TV signalsTV signals

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EnvironmentEnvironment

Environment = not the systemEnvironment = not the system We define environment as every We define environment as every

communication that is outside of communication that is outside of the systemthe system

E.g., cell and metabolites in the E.g., cell and metabolites in the inter-cellular fluidinter-cellular fluid

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Where is the boundary ?Where is the boundary ?

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System and environmentSystem and environment

Communication density boundaryCommunication density boundary Dense communication within the Dense communication within the

system rare communications with system rare communications with outside of the systemoutside of the system

Note: the boundary may changeNote: the boundary may change

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System – environment System – environment interactions 1interactions 1

System: communications between System: communications between communication unitscommunication units

The communication units are The communication units are independent of the system, and they may independent of the system, and they may participate in other communications, participate in other communications, which are not part of the systemwhich are not part of the system

The behaviour of communication units The behaviour of communication units may be influenced by their participation may be influenced by their participation in outside the system communicationsin outside the system communications

E.g., cordless phone and interference with E.g., cordless phone and interference with electronic equipmentselectronic equipments

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System – environment System – environment interactions 2interactions 2

The effects on the behaviour of The effects on the behaviour of communication units caused by communication units caused by communications not part of the system communications not part of the system inducing modified communications inducing modified communications within the system are the effects of the within the system are the effects of the environment on the systemenvironment on the system

E.g., antibiotics block the proper E.g., antibiotics block the proper communications (generation of communications (generation of proteins) within the cell and cause the proteins) within the cell and cause the destruction of the cell’s systemdestruction of the cell’s system

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System actionsSystem actions Communications within the system Communications within the system

happen by behaviour of communication happen by behaviour of communication unitsunits

Such behaviour modify the participation Such behaviour modify the participation of these communication units in of these communication units in communications that are part of other communications that are part of other systems which make part of the systems which make part of the environment of the selected systemenvironment of the selected system

In this way the system acts on the In this way the system acts on the environmentenvironment

E.g., the cat’s movements may warn the E.g., the cat’s movements may warn the mousemouse

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System perceptionsSystem perceptions

The environment modifies the The environment modifies the behaviour of communication units that behaviour of communication units that generate the communications which generate the communications which make the systemmake the system

The communications within the system The communications within the system change in effect, the system perceiving change in effect, the system perceiving in this way the environmentin this way the environment

E.g., a mouse appears in the sight of a E.g., a mouse appears in the sight of a catcat

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Possibility - conceptPossibility - concept In a sequence of communications one In a sequence of communications one

communication may be followed by communication may be followed by many others, all these are possible many others, all these are possible communicationscommunications

The possible communications form the The possible communications form the possibility space of continuation for a possibility space of continuation for a communicationcommunication

E.g., cat sees a mouse, may approach it E.g., cat sees a mouse, may approach it in many waysin many ways

E.g., talking to a friend a sentence may E.g., talking to a friend a sentence may be followed by many othersbe followed by many others

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Sequence of Sequence of communicationscommunications

Every communication determines Every communication determines the range of possible following the range of possible following communicationscommunications

E.g., in normal human speech E.g., in normal human speech there are rules which determine there are rules which determine which sentence may follow a which sentence may follow a previous sentenceprevious sentence

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Reference - conceptReference - concept

In a communication system each In a communication system each communication references other communication references other communications that are /were part of communications that are /were part of the systemthe system

The communications which are The communications which are referenced are those, which determine referenced are those, which determine the possibility space from which the the possibility space from which the current communication is chosencurrent communication is chosen

E.g., talking about a friend to a friend or E.g., talking about a friend to a friend or to a foreign personto a foreign person

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Communication systems: Communication systems: probabilistic interpretation – probabilistic interpretation – 1 1

Within a system new Within a system new communications emergecommunications emerge

The probability distribution of The probability distribution of these new communications over these new communications over the space of possible the space of possible communications (the current communications (the current possibility space) describes the possibility space) describes the systemsystem

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Communication systems: Communication systems: probabilistic interpretation – probabilistic interpretation – 2 2

Example:Example: ‘‘The human eye is extremely sensitive.’The human eye is extremely sensitive.’

A. ‘Researchers, hoping one day to build robots A. ‘Researchers, hoping one day to build robots that can see as well as humans, are now trying to that can see as well as humans, are now trying to copy what is known about the retina onto silicon copy what is known about the retina onto silicon chips.’chips.’

B. ‘Let’s consider the camera for a moment.’B. ‘Let’s consider the camera for a moment.’ C. ‘They are usually the ones who govern C. ‘They are usually the ones who govern

nations.’nations.’

How likely are these continuations ?How likely are these continuations ?

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Communication systems: Communication systems: probabilistic interpretation – probabilistic interpretation – 33

0.1 0.05 0.2 0.02 0.03 0.2 0.35 0.05

0.15 0.01 0.1 0.2 0.04 0.3 0.1 0.1

0.2 0.15 0.02 0.3 0.1 0.03 0.15 0.05

0.4 0.01 0.02 0.02 0.35 0.02 0.03 0.15

0.1 0.05 0.2 0.02 0.03 0.2 0.35 0.05

Current Possible

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System perceptions – System perceptions – revisited 1revisited 1

The environment induces changes in the The environment induces changes in the communication units that affect the communication units that affect the communications produced by thesecommunications produced by these

Such effects can be seen as a change in the Such effects can be seen as a change in the probability distribution of new communications probability distribution of new communications that may emerge, over the space of possible that may emerge, over the space of possible communicationscommunications

The actual new communications provide a The actual new communications provide a sample of the actual probability distributionsample of the actual probability distribution

The difference between the expected and the The difference between the expected and the actual distribution represents the perception of actual distribution represents the perception of the systemthe system

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System perceptions – System perceptions – revisited 2revisited 2

0.1 0.05 0.2 0.02 0.03 0.2 0.35 0.05

0.15 0.01 0.1 0.2 0.04 0.3 0.1 0.1

0.23 0.12 0.03 0.25 0.12 0.04 0.12 0.09

0.35 0.06 0.01 0.08 0.31 0.01 0.07 0.11

0.1 0.15 0.1 0.12 0.01 0.12 0.3 0.1

Current Possible

0.2 0.15 0.02 0.3 0.1 0.03 0.15 0.05

Env

iron

men

t

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Why do systems exist ?Why do systems exist ? Communication systems are created by the Communication systems are created by the

emergence of dense inter-referencing emergence of dense inter-referencing communications between communication units communications between communication units surrounded by a rare set of communicationssurrounded by a rare set of communications

Such systems exist by the generation of new Such systems exist by the generation of new communications referencing other earlier communications referencing other earlier communications that are part of the systemcommunications that are part of the system

Only systems that reproduce and expand can Only systems that reproduce and expand can be observedbe observed

Systems exist to maintain and reproduce Systems exist to maintain and reproduce themselves, this is their main functionthemselves, this is their main function

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Do systems have a Do systems have a function ?function ?

From the point of view of an external From the point of view of an external observer it may appear that the observer it may appear that the systems has some particular function systems has some particular function within a larger systemwithin a larger system

From inside the single main function From inside the single main function of the system is its own reproductionof the system is its own reproduction

E.g., communications between E.g., communications between bureaucrats bureaucrats

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System expansionSystem expansion

Systems main function: self Systems main function: self reproductionreproduction

Systems that reproduce and Systems that reproduce and expand by attracting more expand by attracting more communication units to generate communication units to generate communications that are part of communications that are part of them may dominate other systemsthem may dominate other systems

E.g., animals, human organisationsE.g., animals, human organisations

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Systems workingSystems working Communications systems generate Communications systems generate

communications that refer to other communications that refer to other communications part of the systemcommunications part of the system

The systems aim to reproduce and expand by The systems aim to reproduce and expand by generating new communicationsgenerating new communications

The systems generate communications that The systems generate communications that induce actions upon the environment by induce actions upon the environment by modifying the behaviour of communication units modifying the behaviour of communication units that produce the system’s communicationsthat produce the system’s communications

The environment acts upon the communication The environment acts upon the communication units, which actions can be perceived by the units, which actions can be perceived by the systemssystems

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Summary – 1 Summary – 1

CommunicationCommunication EnvironmentEnvironment System boundariesSystem boundaries

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Summary – 2 Summary – 2

ActionAction PerceptionPerception PossibilityPossibility ReferenceReference Main function of systemsMain function of systems

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Q&A – 1 Q&A – 1

1.1. Is it true that the economy of North Tyne Is it true that the economy of North Tyne Side forms a separate system ? Why ?Side forms a separate system ? Why ?

2.2. Is it true that sodium (Na+) ions are part of Is it true that sodium (Na+) ions are part of a cell even outside of the cell membrane ?a cell even outside of the cell membrane ?

3.3. Is it true that this lecture is part of the Is it true that this lecture is part of the environment for the UK political system ?environment for the UK political system ?

4.4. Is it true that a seminar on human rights Is it true that a seminar on human rights with participation of politicians is an action with participation of politicians is an action of the legal system on the political system ?of the legal system on the political system ?

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Q&A – 2 Q&A – 2

5. Is it true that measuring the university choice of 5. Is it true that measuring the university choice of high school graduates is a perception of the high school graduates is a perception of the university system about its social environment ?university system about its social environment ?

6. Is it true that when we talk with our GP we should 6. Is it true that when we talk with our GP we should refer to recent political events in order to be refer to recent political events in order to be understood ?understood ?

7. Is it true that we can tell a story about an old 7. Is it true that we can tell a story about an old friend to a new friend without referring friend to a new friend without referring explicitly to anything that is already known by explicitly to anything that is already known by our new friend ?our new friend ?

8. Is it true that the main function of a politician is 8. Is it true that the main function of a politician is to represent his/her constituency ?to represent his/her constituency ?