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An Awareness Virtual Lecture
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Engineering Self-Organising andSelf-Aware Electronic Institutions
Jeremy Pitt
Department of Electrical & Electronic EngineeringImperial College London, UK
AWARENESS Online Lecture SeriesRecorded: Amsterdam, 22-23 September 2011
Agenda
AgendaI Problem: resource allocation in open networks and infrastructuresI Proposal: self-organising electronic institutionsI Method: sociologically-inspired computingI Formal Characterisation and Experimental ResultsI Self-aware InstitutionsI Summary and Conclusions
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 1 / 19
Problem Specification
Resource allocation in open embedded systemsI Common Pool Resource (CPR) problem
I exogenous: resource level determined by the environment, i.e. by externalforces beyond the control of the agents (e.g. water appropriation)
I endogenous: resource level determined by the contributions of the agentsthemselves (e.g. MANET, sensor networks)
I hybrid: both exogenous and endogenous, resource level determined byexternal forces and internal contributions (e.g. smart grid)
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 2 / 19
Informal Operation
Resource allocation occurs in timeslicesI Exogenous
I Agents demand resourcesI Agents are allocated resourcesI Agents appropriate resources
I EndogeneousI Agents contribute resourcesI Agents demand resourcesI Agents are allocated resourcesI Agents appropriate resources
I NotesI Agents can ‘mis-behave’I Physical and conventional actions
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 3 / 19
Formal Description
Depends on the environmentI Exogenous: resource allocation problem for set of resources P
ui = ri , ifi∑
j=1
rj 6 P
= 0, otherwise
I Endogenous: linear public good game
ui =an
n∑j=1
rj + b(1− ri), where a > b andan
< b
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 4 / 19
Proposal: Introspection
How do people do it?I Make up and write down rules to regulate/organise behaviourI Example 1: deliberative assemblies
I Robert’s Rules of Order (RONR): standard reference manual for proceduresin deliberative assemblies
I Anything goes unless someone objectsI Example 2: common-pool resource (CPR) management
I Ostrom: self-governing institutionsI An alternative to privatisation or centralisation
I Common features of both examples: role-based protocols forimplementing conventional procedures
I Self-organisation: change the rules according to other (‘fixed’,‘pre-defined’) sets of rules
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 5 / 19
Ostrom: Governing the Commons
Definition of an InstitutionI “set of working rules that are used to determine who is eligible to
make decisions in some arena, what actions are allowed orconstrained, ... [and] contain prescriptions that forbid, permit orrequire some action or outcome”
I Implicitly includes RONRI Conventionally agreed, mutually understood, monitored and
enforced, mutable and nestedI Nesting: tripartite analysis
I operational-, collective- and constitutional-choice rulesI Decision arenas
I Requires representation of Institutionalised Power
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 6 / 19
Ostrom: Sustainability of the Commons
Principles of enduring institutions1. Clearly defined boundaries2. Congruence between appropriation and provision rules and the
state of the prevailing local environment3. Collective choice arrangements4. Monitoring by appointed agencies5. Flexible scale of graduated sanctions6. Access to fast, cheap conflict resolution mechanisms7. Systems of systems8. No intervention by external authorities
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 7 / 19
Method
Sociologically-inspired computingI How to build a computational model of self-organising CPR?
PreFormal‘Theory’
ObservedPhenomena
Calculus1. . .Calculusn
ComputerModel
ObservedPerformance
6
?
- -FormalCharacterisation
PrincipledOperationalisation
TheoryConstruction
SystematicExperimentation
⇐Expressive capacity
Conceptual granularity⇒Semantic formality
Computational tractability
I Apply method to Ostrom’s theory of CPR using a formal calculus
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 8 / 19
Calculusi (1 6 i 6 n)
Dynamic Norm-Governed Multi-Agent SystemsI Norm-governed system specification
I Physical power, institutionalised power, and permissionI Obligations, and other complex normative relationsI Sanctions and penaltiesI Roles and actions (communication language)
I ProtocolsI Protocol stack: object-/meta-/meta-meta-/etc. level protocolsI Transition protocols to instigate and implement change
I Specification SpaceI Degrees of Freedom (DoF) define changeable components of a specificationI Defined a ‘space’ and a notion of distanceI Move between points, define rules about moving between points
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 9 / 19
Analysis: CPR Institutions as NG-MAS
Ostrom institutions as dynamic specifications
ConstitutionalChoice
CollectiveChoice
OperationalChoice
Meta-Meta-LevelProtocol
Meta-LevelProtocol
Object-LevelProtocol
AppropriationProvisionMonitoringEnforcement
Policy MakingAdjudicationManagement
GovernanceFormulation
Ostrom Institutional Rules Artikis Dynamic Specification
Access ControlResource AllocationMonitoring
Role AssignmentRule SelectionDispute Resolution
?
?
?
?
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 10 / 19
Formal Characterisation
The Event Calculus (EC)I A general purpose action language for representing events, and for
reasoning about effects of eventsI A logical semanticsI Action language:
I Events occur at specific times (when they ‘happen’)I A set of events, each with a given time, is called a narrativeI Given a start state and a narrative, can compute what holds in the end state
(and each point in between)I Implementation
I Implementation directly in Prolog (as well as in other programminglanguages)
I In Prolog, the specification is its own implementation;I Hence, executable specification
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 11 / 19
Institutional Principles in Event Calculus
The institutional principles as EC ProtocolsI Clearly defined boundaries⇒ role-assignment and role-based
access controlI Congruence between appropriation and provision rules and the
state of the prevailing local environment⇒ mapping Bf to If byopinion formation and expressed preferences
I Collective choice arrangements⇒ voting protocol and participatoryadaptation
I Monitoring⇒ event recognitionI Flexible scale of graduated sanctions⇒ objections and sanctionsI Access to fast, cheap conflict resolution mechanisms⇒ alternative
dispute resolutionJeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 12 / 19
Experimental Testbed
The EC rules can be used as a specification for anexperimental testbed
I Class diagram:
Memberag_name {I}activitycompliancy_degree
request();appropriate();rev_behaviour();appeal();
Institutionresource_levelra_methodmonitoring_freqsanctioning_gradeadr_methodunintent_violation
refill();
Monitorag_name
report();
* 1
Headag_name
allocate();declare_raMeth();sanction();uphold();exclude();
0..1
1
10..1
I Agent state chart:
cactiveMember
inactiveMember
allocate
[comply !Pr 4]
[!comply Pr 4]v
v
[(|offences| <= limit Pr 5) (uphold Pr 6)]v v v
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 13 / 19
Experiments
Experimental setupI Define agent population and profiles
I 100 agents, active member’s demand ≈ 50, varying refill ratesI 100 trials with a maximum lifespan tmax = 500I all or only 50% of the agents complyI agents get chance to change their behaviour when readmittedI no or low probability of unintentional violation
I Increasing subset of principles selectednone: agents allocate at will
2: ra method ∈ {queue, ration}, depending on P2/4: + high or low level of monitoring (permanent exclusion for first detected
offence)2/4/5: + temporary exclusion (for 5/10/15 time steps, permanently thereafter)
2/4/5/6: + dispute resolved if time between two offences > set amount of steps
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 14 / 19
Experimental Results
Iterate over agent population with active principlesI Example: 50% non-compliant, high monitoring, unintentional
violation
I Primary observationsI Principles fit for purpose for enduring electronic institutionsI Sustainability (endurance and ‘fairness’) sensitive to congruence (trade-off
cost vs. agent profiles)Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 15 / 19
Self-Aware Institutions
Leverage experimental outcomeI Experiments suggest design-time guidelines for self-organising
institutionsI Codify the guidelines in same logical formalismI Make the guidelines available at run-time for use by the components
themselvesI One of the 5 dimensions of self-awareness
I measurement: for (self-)observation, exchange of informationI adaption: adapt behaviour/rules to optimise individual/collective performanceI invention: invent or discover new behaviour from introspectionI self-simulation: reason about ‘what if’ questions to justify choicesI systems of systems: understanding the hierarchy and interconnectedness of
systems
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 16 / 19
Applications of Self-Awareness
Smarter InfrastructureI Interleaving environmental awareness, specification space,
executable specification of social rules, and social computationalchoice
Specification Instance (Policy)
Specification Space
Infrastructure Prosumers Social Network
Sensors
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 17 / 19
Summary and Conclusions
SummaryI Resource allocation in open systems can be considered from the
perspective of CPR managementI The principles for enduring institutions can be given a uniform logical
axiomatisation in an Action LanguageI The axiomatisation can be used as the basis of an experimental
testbed; experiments show that the same principles are necessaryand sufficient conditions for sustainable electronic institutions
ConclusionsI Inter-disciplinary research requires a well-found methodI Foundations for developing self-aware electronic institutions
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 18 / 19
Acknowledgements
AcknowledgementsI Joint work with Julia Schaumeier (Imperial College London) and
Alexander Artikis (NCSR, Athens)I FP Project AWARENESS FP7 257154
Jeremy Pitt Engineering Self-Organising and Self-Aware Electronic Institutions 19 / 19
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