MULTI-AGENT ORGANIZATIONAL MODEL FOR

ECONTRACTING

Benjamin G

ATEAU, Djamel KHADRAOUI, Eric DUBOIS

CRP Henri Tudor

29, Av. John F. Kennedy, L-1855 Luxembourg

Olivier BOISSIER

SMA/SIMMO/ENSM Saint-Etienne

158, cours Fauriel, F-42023 Saint Etienne Cedex 02

Keywords:

Multi-Agent System, Organizational Model, eBusiness, eContracting, Sanction, Normative Speciﬁcation.

Abstract:

This paper covers development and analysis tools, software and system architecture engineering and devel-

opment methodologies. It introduces the MOIS E

(Model of Organization for multI-agent System) model

seen under three points of view : structural, functional and deontic. In practical, this model is available as a

JAVA component. The original contribution of the paper is the extension of the model to take into account

the notion of sanctions. These ones are necessary in order to control the respect of normative speciﬁcations

(obligation, permission, prohibition) of behaviors. The results of the generalized model are implemented on

an eCommerce application dealing with eContracting.

1 INTRODUCTION

Nowadays only conducting eBusiness is still not ob-

vious because of numerous obstacles. To assist users

in conducting these transactions, we often associate

them with software. In our works, an agent-based sys-

tem is proposed due to the natural decomposition and

abstraction of intelligent agents that mimic a human

organizational structure and behavior. We can say

that the need for intelligent agents has never been as

greater as pressures to make business grow. Research

and development activities in this area increased due

to the market demands as well as systems needs to

solve various and complex problems related to the do-

main.

This paper offer a complete organizational model,

called MOISE

(Model of Organization for multI-

agent System) (Hubner et al., 2002), that considers

the structure, the functioning, and the deontic rela-

tions among them to explain how Multi-Agent Sys-

tems (MAS) organization collaborates for its purpose.

The objective is to control agents behaviors and re-

spect of rights and duties described by deontic rela-

tions. This model practice is represented by a JAVA

component which provides an empty deﬁnition of an

agent able to organize itself regarding the society and

others agents.

2 MULTI-AGENT SYSTEM

DOMAIN

Within Multi-Agent Systems (MAS) domain, an

agent is a real or virtual entity which interacts with

a shared environment or directly with others agents

by perceiving and acting. Its behavior can be consid-

ered as autonomous because of its ability to have a

local self-control (Jennings et al., 1998). The capac-

ity of each agent to determine its own goals expresses

the concept of agent autonomy. These goals can be

determined according to environment conﬁguration,

agents motivations, agents included in the system or

contracted engagements.

Multi-Agents System can be deﬁned as a dis-

tributed system composed by a set of agents interact-

ing according to cooperation or competition modes.

Nevertheless the agents of a MAS do not compose a

collection of juxtaposed entities but a structure of en-

tities able to work together to solve a problem too dif-

ﬁcult for an agent left alone (Chaib-draa et al., 2001).

Consequently we can say that there are different kinds

of dependencies networks between agents.

Interfering managements and conﬂicts are the main

problems of this domain research due to agents au-

tonomy. These lasts relate to shared environment and

common resources between the agents and to agent

striving towards personal goals that can be incom-

patible, complementary or in competition. Sophis-

489

Gâteau B., Khadraoui D., Dubois E. and Boissier O. (2004).

MULTI-AGENT ORGANIZATIONAL MODEL FOR eCONTRACTING.

In Proceedings of the Sixth International Conference on Enterprise Information Systems, pages 489-492

DOI: 10.5220/0002657404890492

 SciTePress

ticated models of such conﬂicts management have

been elaborated in the domain. These models re-

veal themselves for example by protocols of negoti-

ation (Zlatev, 2002), organizational models (Dignum

et al., 2002), etc.

Our work deals with the development of models

that are common to the whole agents. These models

deﬁne and structure the issues of autonomous agents

overall activity. The objective contains two steps:

the ﬁrst one is the construction of contract models,

scenarios or institutions in which the common rules

governing the operation of the agents could be im-

plemented in a declarative way. The second one is

the construction of models and architectures of agents

able to conform to these rules. These problems are ap-

proached in a context of open and dynamic systems.

The objective of our research activity takes into ac-

count the development of a set of models in order

to constrain and control the behavior of autonomous

agents while making the agents reasoning and pre-

serving their autonomy towards constraints interpre-

tation. We present in the next section an extended

model of MOISE

to introduce the notion of sanction.

It is necessary in order to control the respect of nor-

mative speciﬁcations (obligation, permission, prohi-

bition) of behaviors.

3 MOISE

ORGANIZATIONAL

MODEL DESCRIPTION

MOIS E

is composed by two core notions: an Orga-

nizational Speciﬁcation (OS) and an Organizational

Entity (OE). An OE is a population of agents func-

tioning under an OS. We can see an OE as an instance

of an OS, i.e., agents playing roles deﬁned in the OS

(role instance), aggregated in groups instantiated from

the OS groups, and behaving as normalized in the OS.

Following this trend, a set of agents builds an OE by

adopting an appropriate OS to easily achieve its pur-

pose. MOISE

OS is formed by a Structural Speci-

ﬁcation (SS), a Functional Speciﬁcation (FS), and a

Deontic Speciﬁcation (DS). Each of these speciﬁca-

tions will be presented in the following subsections.

3.1 Structural Speciﬁcation (SS)

In MOI SE

three main concepts, roles, role relations,

and groups, are respectively used to build the individ-

ual, social, and collective structural levels of an orga-

nization.

As shown on the Fig. 1, the SS of a MAS organi-

zation is formed by a set of roles, a set of group root

speciﬁcations (which may have their sub-groups, e.g.

the group speciﬁcation team), and the inherited rela-

tion on the set of roles.

back

leader

goalkeeper

player

middle

attacker

coach

soc

1..1

3..3

0..1

4..4

3..3

1..1

1..2

1..1

acq

com

aut

acq

aut

com

compat

intra-group

key

min..max

composition:

inheritance:

role

Abs Role

inter-group

links

1..1

sub-groups scope:

group

defense

attack

team

Figure 1: A structure example of a soccer team

3.2 Functional Speciﬁcation (FS)

The FS in MO IS E

is based on the concept of mis-

sions (a set of global goals) and global plans (the

goals in a structure). These two concepts are gath-

ered in a Social Scheme (SCH) which is a goals tree

where the root is the SCH goal and where the respon-

sibilities for the sub-goals are split into missions.

Two types of SCH are necessary to express the var-

ious missions:

• The social diagram of execution which deﬁnes the

missions to be used for the achievement of the root

goal.

• The social diagram of sanctions which deﬁnes the

missions to be used in the sanction part of the de-

ontic speciﬁcation (see next section).

3.3 Deontic Speciﬁcation (DS)

The DS explains the way the organization contributes

to achieve common goals. The DS is the link between

the SS and the SF by deﬁning relations between roles

and missions. The deontic speciﬁcation of the con-

tract expresses rights and duties of the participants

in terms of obligations, permissions and prohibitions

with time constraints. For instance with a deontic ex-

pression, we can express the fact that a role has the

obligation to execute a mission by meeting a deadline.

In order to avoid agents lack of deontic expressions

respect coming from their ability to reason and to de-

cide autonomously, each deontic expression is asso-

ciated to sanctions (penalties and rewards). An agent

which does not respect an obligation is punished and

ICEIS 2004 - ARTIFICIAL INTELLIGENCE AND DECISION SUPPORT SYSTEMS

490

if the MAS provide such service its reputation could

be prejudiced. These sanctions constitute tools to

guide the agents behaviors and to obtain a quite stable

society.

agent

role

mission

scheme

goal

group

FS

SS

DS

OS

OE

Figure 2: Organizational Entity

Within the MOISE

extension we achieved a sanc-

tion is a special deontic expression with a condition.

A sanction could be positive or negative. As said in

the previous section, we could have a social diagram

of sanctions because these special deontic expressions

are linked between them. The root deontic expression

is generally an obligation. According to the respect

of the obligation or not there is a positive or negative

sanction. According to the result of this sanction there

is another sanction, and so on.

The structural, functional and deontic speciﬁca-

tions (SS, FS and DS) constitute an organizational

speciﬁcation (OS). An organizational entity (OE) is

an OS instance and the result of agents playing roles.

Fig. 2 summarizes the actual organization model.

4 CASE STUDY :

ECONTRACTING

APPLICATION

Our aim goal is to apply our model on an eCommerce

platform used to trade intangible assets. It is basically

an eContracting application dedicated to translation

services, as described in (Khadraoui and Dubois,

2003)). The model of contract presented hereafter

is based on the organizational model MOISE

Within this framework a contract is seen like an

Organizational Entity i.e. like the assignment of an

Organizational Speciﬁcation with a set of agents.

The OS could be seen as a template of contracts. It

deﬁnes constraints on groups, roles and missions.

A contract is made up of:

• an unique identiﬁer;

• an header which gathers:

– a list of agents’ identiﬁers participating in the

contract and playing roles appearing in the SS;

– a list of services involved in the contract with

attributes speciﬁcation deﬁned during the con-

tract negotiation. Services improvement appears

in the FS as goals;

– a list of products involved in the contract with

attributes values deﬁned in the contract deﬁni-

tion phase. The action of producing these goods

appears as goal in the FS.

• some general conditions;

The contract general conditions represent the

whole requirements relating to the provided

services or products. The negotiation step of the

contract introduces partly the deﬁnition of these

attributes.

• a Structural Speciﬁcation (SS) :

The structural speciﬁcation of the contract ex-

presses the organization in term of roles (Employe,

Employer or Arbitrator for instance), links be-

tween roles and groups.

• a Functional Speciﬁcation (FS) :

The contract functional speciﬁcation describes

missions to carry out for the services or products

realization. The FS consists of social diagrams.

• a Deontic Speciﬁcation (DS) :

The DS is a set of deontic expressions which can

be an obligation, a permission, a prohibition or a

sanction

hDSi ::= ‘(’ hdeonticExpi*‘)’

hdeonticExpi ::= ‘(’ :id hidDEi ‘::’[hDConditioni ]

‘ →’ hdeonticReli hroleIdi

‘(’hdeonticActi hrelationi hdeadlinei‘)’‘)’

hDConditioni ::= hDConditioni ‘&&’ hDConditioni |

‘Respect(’ hidi ‘)’ | ‘NonRespect(’ hidi ‘)’ |

Valid(’hactionIdi‘)’ | ‘NonValid(’hactionIdi‘)’

hdeonticActi ::= ‘do’‘(’(hmissionIdi hargumenti|

hactionIdi hargumenti)‘)’

A deontic expression hdeonticExpi consists in a con-

dition hDConditioni and in an action that is realized if

and only if the condition is met.

We use the BNF meta-language (Backus-Naur Normal

Form).

MULTI-AGENT ORGANISATIONAL MODEL FOR E-CONTRACTING

491

The ﬁeld hdeonticReli deﬁnes the deontic relation that

is activated if the condition is satisﬁed. It may take

the values ’O’ for an obligation, ’P’ for a permission

and ’I’ for a prohibition.

The hroleIdi refers to the role deﬁned in the SS :

the agent playing this role will have to behave

according to the deontic relation that precedes this

role with respect of the concerned deontic action.

This last is deﬁned with reference to the missions

(hmissionIdi) or to the action (hactionIdi) detailed in

the FS. We added a temporal expression to this

deontic relation. For the moment we only used

the precedence operator ‘<’ but an extension is

possible.

This deontic speciﬁcation enables us to specify and

structure the contract execution. The setup of a con-

tract is done by deﬁning the header, the general condi-

tions and the structural, functional and deontic speci-

ﬁcations. In other words we describe the elements of

the contract, the organization of the participants, the

clauses and ﬁnally the contract execution methods.

Thanks to the structure of MOISE

our model pro-

posal introduces independently the structural part and

the functional part of it. The structural speciﬁca-

tion deﬁnes the roles and the obligations linking these

roles within the contractual group. The FS deﬁnes

the whole missions which will be involved in the con-

tract. Missions are organized in the social diagram

of execution which represents the contract execution

structure. Other missions are located in the social di-

agram of sanction which speciﬁes the ones related to

the sanctions. This allows distinction between normal

and exceptional scenarios of the contract (in case of

non-respect of engagement). All necessary elements

to the implementation of the contractual relation was

deﬁned beforehand in the header and the general con-

ditions of the contract. Finally the deontic speciﬁ-

cation establishes the link between the structural and

functional aspects to deﬁne the various scenarios of

execution with an adequate representation that per-

mits the course of the sanctions and to reason on the

consequences of the non-observance of a clause.

5 CONCLUSION

We presented in this paper a new approach that pro-

vides an organizational model for Multi-Agent Sys-

tems. The concept of organization has been described

through three views: an structural view (group, role

and relations between them), a functional view (plans,

goals and missions) and a deontic view (association of

roles with missions involving a deontic operator and

a concept of sanction in case of non-respect of com-

mitments).

The notion of sanction has been added to the initial

MOIS E

model introduced in (Hubner et al., 2002).

This constrains the agents behaviors and controls their

autonomy. Actually an agent that has to execute its

missions can loose commitment because of others

missions allowing as well the achievement of local

goals and takes priority. In order to avoid a commu-

nity of airy agents, a reputation could be built on the

sanctions associated with validation or not of an exe-

cuted execution.

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