Multi-agents

Interaction

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outline

Interaction

 Introduction

• Definitions, principle

 Agent communication Language

• Speech acts

• KQML, FIPA-ACL,

 Interaction Protocol

•

Interaction protocol formalism

Interaction protocol examples

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Introduction

Definition

 Générale [Morin 77]

•

Interactions are reciprocal actions modifying the behavior

or nature of elements, bodies, objects, phenomena in

presence or influence.

 Multi-Agent [Ferber 95]

• Dynamic linking of two or more agents through reciprocal

actions.

Autonomous Vehicles interact through

1) Their perceptions of others

2) Their communications

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Introduction

Definition

 Four ways of interacting between agents [Werner 89]

• No communication: agents do not communicate, either they interact by perception of the

environment or they can achieve their goal without external help.

• Sending signals: agents synchronize by sending coded messages.

• Sending plans: the transfer of information concerns the agents' tasks and

beliefs.

• Sending messages: this mode of communication, the most used in the SMA

community, allows agents to exchange their intentions and needs.

No communication: the positions, movements, turn signal

Sending signal: beep the horn

Sending plans: send its direction at a junction

Sending messages: share its intention to overtake

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Introduction

Communication

 Problematic [Shannon 48]

 Definition : Communication is the voluntary

exchange of information caused by the production

and perception of symbols from a shared system

of conventional symbols. [Russel et Norvig 03]

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Agent AAgent BContexteAContexteBMessage3Message2Message1outline

Interaction

 Introduction

• Definitions, principle

 Agent communication Language

• Speech acts

• KQML, FIPA-ACL,

 Interaction Protocol

•

Interaction protocol formalism

Interaction protocol examples

Institut Mines-Télécom

Agent communication Language

Introduction

 Initial hypothesis: A common language constitutes an

interface between agents.

• Syntax: The way symbols are structured,

• Semantics: meaning of the symbols used,

• Conversation: Management of message sequences.

 Sources

• Theory of Language Acts [Austin 62, Searle 72, Vanderveken 88].

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Agent Communication Language

Speech Act theory

 Principle

•

In speech-act theory, verbal actions are called performatives, they are the

building blocks of natural language.

 Taxonomy (Searle)

• Assertives are used to give information about the world by asserting

something.

─ I inform you that I’m married

• Directives are used to give instructions to the recipient.

─ I request you to come to my wedding

• Commissives commit speakers to perform certain acts.

─ I promise to be faithful

• Expressives are used to give the addressee information about the

speaker's mental state.

─ I apologize to miss your wedding

• Declaratories perform an act by the very fact of pronouncing the

utterance.

─ I marry you

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Agent Communication Language

Speech Act Theory

 The same content may have different

interpretation according to the used speech act

 A says to B: “go to the position p1”

Assertion

Directive

B knows that A goes to the position p1

A asks to B to go to position p1

Commissive

not sure that A (or B) goes to p1

Expressive

Declaratory

A think to go to p1

???

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Agent Communication Language

Speech Act Theory

 A performative is composed by

•

locutionary component: production of a sentence using

a given grammar and lexicon.

Illocutionary component: effect that the sender of the

message wants to produce on the recipient

• Perlocutionary component: effect of the message on

the recipient

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Agent Communication Language

Speech Act theory

 Agent A sends the message: « please, close the window,

I’m cold » to the agent B

•

locutionary component: production of a sentence using a given

grammar and lexicon.

─ A writes and sends the message

Illocutionary component: effect that the sender of the message

wants to produce on the recipient

─ A wants an action of B, the strength of the message is enforced by

“please”

• Perlocutionary component: effect of the message on the recipient

─ B should close the window or propose an alternative to the justification

of the demand “I’m cold” for instance he could give a coat

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Agent Communication Language(ACL)

Message

 A message is a performative with a data structure

 ACL is defined by

• The definition of a performative

• The existing performatives

• The data structure of the message

 ACL used at least a data structure composed of the

following fields

• Sender, Receiver, Language of the content, Ontology,

Message content.

 2 main ACL

• KQML

• FIPA-ACL

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Agent communication Language

KQML

 Knowledge Query and Manipulation language

 The principle is to separate

•

the semantics related to the communication protocol

(independent of the application domain)

from the semantics related to the message content

(application-dependent).

 Historic

• 1993 result of the DARPA-KSE (knowledge sharing

effort) consortium

• Designed to exchange information and knowledge

between agents

• Goal: develop generic tools to promote the

interoperability of heterogeneous agents

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Syntaxe

KQML

Message Layer

Communication Layer

Content Layer

(KQML-performative

<text>

:language

:ontology

<text>

:reply-with <text>

<text>

:sender

<text>

:receiver

:content

)

(ask-one

:language LPROLOG

:ontology NYSE-TICKS

:reply-with ibm-stock

:sender joe

:receiver stock-server

:content (PRICE IBM ?price)

)

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KQML

Speech Act