Research On Normative Multi-Agent Architecture For Autonomic Service Cooperation Environment: Representation, Enforcement And Reasoning

With the rapid development of network and information technology,distributed computing technology has got rapid growth and been wildly applied.Distributed cooperation becomes increasingly important in applications.It is considered a promising method that resources is managed and controlled by agents,and composed to Multi-Agent Systems(MAS) for cooperative work.In the study of the MAS area, researchers have come to realize that a loosely coupled cooperation mode is the future need for organizations and individuals.Therefore,research on MAS that is composed by heterogeneous and selfish agents becomes a main topic in the area.However, because agents try to maximize their own interests and differences in the level of cooperative participation,it easily leads to the "negative collective utility" problem.In addition,as the clandestine character and autonomy of Agent,agent behavior is unpredictable and uncontrollable.It causes mistrust between agents,resulting in the "crisis of credibility" problem in MAS.Normative Multi-Agent Systems(NMAS) is considered as a promising method to solve these problems.NMAS uses norms to restrict the behavior of members in order to achieve multi-agent coordination with each other.It is mechanism between centralized control and complete P2P mode.So it is considered as an effective method to achieve credible cooperation in MAS.However,current research is mainly concentrated on theory and abstract models,still being in its infancy and lack of practical operational framework and effective model for applications in many aspects of this field.First,there is no clear background for current models.They mostly focus on commonness of norms system,rather than norms system under specific environment.It results in the mismatch between certain aspects of applications and current models.Another big problem in NMAS research is the lack of Operability. First,it is lack of systems architecture and set of methodologies to support the establishment and operation of normative systems.Second,research on norm representation is currently focused on attributes of norms and logic itself,such as completeness,consistency and other considerations,while the lack of standardized expression of operability,such as easy for decision-making,and easy to determine violations.Third,it is lack of in-depth study and effective model to support normative enforcement,including determination and implementation of violations and penalties. Fourthly,it is hard to achieve the preconditions and the assumptions proposed by the current models of normative reasoning.And it is lack of probabilistic method of normative reasoning and decision-making. To address the above problems,this thesis takes in-depth study and exploration on many aspects of NMAS architecture,norms expression,reasoning and implementation, under the background of autonomic service cooperation.Research in this thesis is focused on improving the operability of normative system models,and tries to form a set of methodology from the macro level to the micro level to support system modeling. Thus it systematically solves the "negative collective utility" and "credibility of crisis" problems.This study points the content and main innovations include:(A) Oriented to autonomic service cooperation environment,proposing a Norm-governed Autonomic Service Cooperation Architecture,namely NASCA. Focusing on the key models,this architecture proposes a three level framework, composed of macro-level of organization framework definition,micro-level of agent reasoning and behavior description and connection level that connect the above two and form VOs.This thesis takes in-depth study of those models in each level.The architecture supports a more workable NMAS system to establish and operate.(B) By combining the deontic and temporal logic operator and extending to traditional logic,this thesis presents an Operational Norm Logic(ONL).Based on this logic,it presents structured,hierarchical norm definition model,namely Organizational Normative Model(ONM).This model is helpful to the clear representation of norm semantic,and it supports the enforcement and reasoning well.It is a supplement for current study,which is lack of support to normative reasoning and enforcement.(C) It is proposed a Normative Enforcement Model(NEM).This model is composed of four parts,including E-institution determination,violation determination, punishment determination and punishment enforcement.Using agent actions (messages) as evidences and ONM as determination foundation,it presents the solutions and algorithms of those four problems.It can enhance the effect of soft constrains of norms.(D) It is proposed a probabilistic reasoning model for normative reasoning and decision-making process,namely NRDM.It aims at the deterministic assumptions of current normative reasoning models,presents a method that computing the norm-compliance trustiness by agents' history action records. Moreover,it revises the trustiness value iteratively according to the total environment trustiness measure.Finally,it brings the trustiness value as a probabilistic node into a Bayesian decision network for uncertain reasoning and decision-making.This thesis presents a set of models for supporting the establishment and effective work of NMAS systems,and modeling in each level.Furthermore,by deeply study in the details of norm representation,enforcement and reasoning,it shows the operability of the architecture.We can conclude that it is proposed a set of effective models for NMAS modeling in autonomic service cooperation environment.