Evolutionary Role Model for Multi-agent Systems
Erdem Eser Ekinci, Oguz Dikenelli
Ege University, Department of Computer Engineering,
35100 Bornova, Izmir, Turkey
erdemeserekinci@gmail.com
oguz.dikenelli@ege.edu.tr
In sociology, the role concept is deeply researched to predict
activities of human organizations and theorized with many sub-theories.
In the same direction, multi-agent system researchers use the role concept
to model and program the agents behaviours, cooperations. But there is
an important point missed out by the MAS researchers: evolution of the
organization. In this paper, by inspiring from the eorts in sociology, we
propose an evolutionary role model for coping with the evolution of the
role-based multi-agent systems.
Abstract.
1
Introduction
The role concept are widely researched from the view points of individual behaviours and cooperation of the agents to incorporate the concept into programmable artifacts of multi-agent systems (MAS). But, when open, distributedconcurrent and unstoppable properties of the MAS[1] are considered, proposed
models and released frameworks remain weak to answer question of how an agent
system spreading over a wide geography can be deployed, managed and maintained. In this paper we propose an abstract role-based model to handle MAS
with an evolutionary approach and paves the way of coping with these deployment, management and maintainance problems. Our model looks multi-agent
organization through individual evolution and organizational evolution perspectives and determines the relations between these perspectives.
2
Evolutionary Role Model
The roots of the word of role, although, reaches the born of the theater in
antique ages. Today sociologists have converted the role concept to a deep theory
to predict activities of individuals by analyzing body of knowledge about human
organizations[2]. As a consequence of these researches, the role concept is dened
as scripts for social conduct and depths of the concept are theorized with many
sub-theories which are Role Playing, The Self, Role Taking, Identity, Role Exit,
Role Transition, Role Alternation, Role Conict, Role Change, Role Making,
Consensus and Conformity [2,3,4,5,6,7,8].
By drawing inspiration from sociology, we propose an evolutionary role model
illustrated in Figure 1. The model is divided into two dierent perspectives:
individual evolution and organizational evolution. In the following list, states
and operations of these separated perspectives are detailed.
Self:
The
Self
depicts all belongings of the agent and covers all properties
of the agent such as beliefs, capabilities, norms, rules, goals and identities of
all taken roles.
Role Making:
The role making is the operation of getharing the explicit
knowledge of a role situated in an organization by the agent. After role
making, the agent learns what the role's goals, rules, beliefs are.
Role Taking: The role taking is the act of participating to a specic organization by commiting the role beliefs, goals and rules.
Identity:
,
By role taking the agent gains a new unique identity in an orga-
nization. This identity is published to whole organization and has important
responsibility in communication.
Role Playing:
Emanating behaviours according to a role in the scope of
organization with the identity of a role instance.
Role Alternation:
An agent can take more than one role and gain many
role instances at the same time. The
alternation is the capability of switching
between these role instances.
Role Exit:
When an agent reaches its goals in the scope of a role, then it
leaves the organization by exiting the role
Role Transition: The role transition
.
is a compound operation that occurs
by exiting a role and taking another one in sequential fashion. The transitions
are previously dened in the organization.
Self-Conict: The Self-Conict
is the state of failing to play multiple roles
at the same time due to conicts. The conict can occur between beliefs,
rules, goals of dierent role instances, or a role instance and the self.
Role Change:
Role change can be dened in short as dierentiation in the
semantics of a role due to the changing requirements and detected conicts.
Consensus:
In the consensus form, each agent, which is member of the
organization, is agreed on the goals, norms, beliefs of the organization.
Organization-Conict:
Conicted organization means participant agents
are dissipated and unable to cooperate with each other due to misunderstanding the semantics of role types.
As depicted in the gure of the model, whole organization is in civious cycle
between organizational conict and consensus forms. Agents begin their lifes by
taking roles whose conceptualizations are agreed on by the whole organization.
But during their individual evolution they get in conicts. Many of these conicts
can be resolved by exiting a role. But some of them requires some changes in
conceptualization of conicting role(s). After changing roles with an engineering
touch, even if agent's internal coherence is obtained, the cooperation is broken
down and organization is dissapeted until others' recognations are conformed to
the new conceptualization of the changed role.
Fig. 1.
3
Evolutionary Role Model
Conclusion
In this paper, we propose an evolutionary role model for multi-agent systems,
which covers individual and organizational evolution, by drawing inspiration
from the role theory propounded in sociology. Similar models are also articulated
previously[9,10]. But, dierently from these models, we dene the organizational
evolution and relate to the individual evolution of agents.
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