joaquim filipe ([email protected]) school of technology polytechnic institute of...

SOCIAL SYSTEMS MODELING USING INTELLIGENT MULTI-AGENT SYSTEMS

Joaquim Filipe([email protected])

School of TechnologyPolytechnic Institute of SetúbalPortugal

This work has been supported in part by the Croatian Science Foundation under the project no. 8537.

Joaquim Filipe (c) 2014 MMORPG Project 2

Information Systems modeling Organizational Semiotics Norms and Social Psychology Information Fields

Agent Paradigms Individual vs. Social focus EDA vs. BDI Agent Models Agency Theory Multi-Agent Systems

Conclusions

Overview

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This presentation intends to introduce a theoretical framework that integrates several theories/well known areas of knowledge: Organizational Semiotics Social Psychology Agency Theory

No MMORG tools or software will be referred in this presentation

Metatheoretical Focus

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MMORPGs facilitate communication between players and involve some degree of teamwork for parts of the game.

Sometimes there is a hierarchical structure (organization).

Need to represent knowledge about The player herself/himself/itself The other players Available roles Communication / Action rules Social norms

MMORPGs are Social Systems

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Social Systems ARE Information Systems

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INFORMAL Inf.System: a sub-culture where meanings are established, intentions are understood, beliefs are formed and commitments with responsibilities are made, altered and discharged

FORMAL Inf.System: bureaucracy where form and rule replace meaning and intention

IT System: Mechanisms to automate part of the formal system

Three main layers of the real information system (Stamper 1996)

October 14Joaquim Filipe (c) 2014 MMORPG Project


The science of signs

Information is made of signs (the atoms of information)

‘A sign … is something which stands to somebody for something in some respect or capacity.’

(Peirce, 1931-58)

Information and Semiotics

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Information is a complex concept. Social issues are relevant: information is constructed by people (constructivism).

Semiotics studies all aspects related to the creation, use and termination of signs. Different aspects of signs must be studied as social

constructs: the (interpreted/negotiated) meaning of signs (semantics),

the way they are used (pragmatics) and how they affect social power systems (social world)

Information Systems Information is carried by signs and used for semantic, pragmatic

and social purposes.

Semiotics, Information and Social Systems

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8Joaquim Filipe (c) 2014 MMORPG Project

Semiotics LadderSOCIAL WORLD - Commitments,

Human Information contracts, law, culture, ...

Functions PRAGMATICS - intentions, communication,

conversations, negotiations, …

SEMANTICS - meanings, propositions,

validity, truth, signification, denotations,…

The IT SYNTACTICS - formal structure, language, logic,

Platform Data, records, deduction, software, files, …

EMPIRICS - pattern, variety, noise, entropy,

channel capacity, redundancy, efficiency, codes, …

PHYSICAL WORLD - signals, traces, physical distinctions,

hardware, component density, speed, economics, …

The Semiotics ladder (Stamper, 1973)

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Norms are deontic entities (obligations/responsibilities) Wright (1963) defines ‘Norm’ as partial synonyms which includes, ‘pattern’,

‘standard’ and ‘type’. So are ‘regulation’, ‘rule’, and ‘law’. Deontic Logic is a higher-order modal logic based on the Obligation operator.

Norms are determined by society or collective agents, and serve as a standard for the members to coordinate their actions.

These social constructs may represent: Common (shared) knowledge Patterns of behaviour which are acceptable within the social

context. Power relations and other social structures

Group members are responsible for adopting and using these norms.

The prime social entity: Norm

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Norms can be:

Perceptual

Cognitive

Behavioral

Evaluative

Social Psychology Classification of Norms

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Corresponding intentional attitudes:

Ontological: to acknowledge the existence of something

Epistemic: to know or adopt a degree of belief

Deontic: to be disposed to act in some way

Axiological: to be disposed in favor or against something in value terms


Sets of norms adopted and used by all the group members. An agent who comes into the group is influenced by

the group’s norms and either adopts them or becomes an “outsider”.

Coallition formation requires merging different information fields (a common problem in emergent organizational structures e.g. VOs)

An organization may need to split up due to information field clashes (e.g. Departments in Universities)

Information Fields

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Several interests may be at stake simultaneously.

Example:

Interest Alignment

- Ind.2 may have interest in situation A while Ind.1 may be interested in situation B If A B it’s ok, otherwise there is a clash of interests

- Ind.2 may be subject to contradictory norms

Social Group 1

Ind.1Ind.2

Social Group 2

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Social Systems and Information Fields

Information Field: System of norms accepted by a community

Semantics, Pragmatics, Social

Shared ontology: Information Fields may overlap

Information Fields can be populated by Individual agents, Collective agents (=>nested IFs), Abstract agents (roles – reflecting organizational

norms).

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<Abstract Agent>::= <set of commitments> Normative (shared) commitments can be

about any type of norms: Perceptual, Cognitive, Behavioral or Evaluative.

Commitments involve Obligations and Authorisations

Roles are Social “Contracts”

A commitment is: <Commitment>::= O | P | F :<agent>:

<norm(args)>

Roles as Abstract Agents

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Useful for social modeling because: Social Systems are (Distributed) Information

Systems Multiple agents and resources Systemic properties (boundaries, control, internal

components, input/output, etc.)

Each individual plays one or more roles but it Has a degree of autonomy Is situated in a social normative and communicative

environment Exhibits a goal-directed behavior Uses knowledge and different forms of reasoning

(inspired in Wooldridge and Jennings definition of agent)

Multi-Agent System Metaphor

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Internal Model: BDI (Beliefs, Desires and Intentions)

Beliefs = set of true propositions about the world

Desires = set of objectives (not necessarily coherent)

Intentions = set of plans

Agent is permanently in an observe-reason-act cycle and adjusts its internal model according to logical rules

Traditional Agent Models

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BDI primitives are meant mainly for creating mental models.

Social context is not critical for mental models.

Desires and Intentions belong to the same norm type (behavioral).

No primitives for perceptual or evaluative norm types.

No concern with the duality individual/social responsibility

Shortcomings of BDI

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The organizational semiotic stance ties every item of knowledge to an agent, who is, in a sense, responsible for it. Formally:

<wff commitment> ::= <agent-term> <norm-term (args)>

Instead of an objective truth, there is a concept of truth that corresponds to the set of agents’ beliefs. Agents are responsible for the consequences of the beliefs they choose to adopt (epistemic component) wff ::= BA(P)

Agents are responsible for their behaviour (deontic component) wff ::= OA(P)

Agents are responsible for their values (axiomatic component) wff ::= VA(P)

Formal Responsibility

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action perception

Axiological Component (values)

Epistemic Component (knowledge)

Deontic Component (behavior)

EDA ModelEpistemic-Deontic-Axiologic

is a pragmatic function that filters perceptions, according to the agent ontology, using perceptual and axiological norms, and updates one or more model components. is an axiological function, that is used mainly in two circumstances: to help decide which signs to perceive and to help decide which goals to put in the agenda and execute is a knowledge based component, where the agent stores his beliefs both explicitly and implicitly, in the form of potential deductions based on logical reasoning.

is a set of plans, either explicit or implicit, the agent is interested in and may choose to execute

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EDA Agent Model

Semiotics+Social Psychology+Agency Theory

How to Formalise?

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There are several agency logics, based on the work of several philosophers.

Belnap’s STIT (See to it that) Inspired in Austin (theory of speech acts) Belnap proposes a new

class of sentences: agentives Agentive wff: <agent-term> <complement(action)>

sees to it that Q

To refrain from acting is an action; not acting is not an action

[α stit: ¬Q] ≠ ¬[α stit: Q]

Agency Theory

[ : ]stit Q

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An action is always performed by an agente who is responsible for it.

In situations where an agent delegates an action to another agent, who is responsible for the action?

[α stit: [β stit: Q]] is meaningless because an agent is, by definition, autonomous.

All α can do, when it delegates on β, is to create an obligation:

[α stit: O[β stit: Q]]This is a Deontic Action-Logic statement.

Delegation and Responsibility

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( )B

Knowledge Representation Epistemic component (Beliefs)

Non-monotonic Logic; belief revision. Belief operator

Deontic component (Obligations) Deontic Agency Logic Agentive Obligation operator

Axiologic component (Values) Prioritised Default Logic (norms as default

rules) Preference defined by a partial order on

norms

[ : [ : ]] ( )stit O stit O

( , )E

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EDA Agents

This structure applies to

- Individual agents

- Collective agents

(a collective agent is an agent)

- Abstract agents (roles)

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Multi-Agent EDA Systems

action perception




action perception




action perception




Communicative Agents

Normative Agents

Social Agents

Goal-Directed Agents

Are Dynamic/Open Distributed Systems

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Social vs. Individual Goalsor why agents act:

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Is a model with sound theoretical support: The model is based in social psychology theory, philosophy and logic.

Unifies individual and social motivations under the concept of obligation This reduces the number of needed concepts, when compared

to other agent models such as BDI (which uses two “motivational” operators).

The same model structure (EDA) can be used for individual and collective agents, This enables a simple recursive structure for organizational

models, where individual models inherit norms from collective models.

Advantages of the EDA Model

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Not widespread Since it is based on higher order

modal logic it is difficult to compute, in general.

No software development tools

Disadvantages of the EDA Model

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Social Groups can be seen as multi-agent systems composed by individual agents in social settings. EDA agents can be individual or collective. A collective agent defines a (shared) information field. A role can be modeled as na abstract agente.

Organizational Semiotics, Social Psychology and Agency Theory provide the basis for a normative agent model. The EDA model provides an adequate formal support

(logic) for each model component: agent implementation can be based on a sound theory instead of ad-hoc mental models.

Conclusions

October 14


“There’s nothing as practical as a good theory” (Ludwig Boltzman)

Thank you for your attention

This work has been supported in part by the Croatian Science Foundation under the project no. 8537

October 14

joaquim filipe ([email protected]) school of technology polytechnic institute of...

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