Marie Pierre Gleizes

Methodologies and Software Engineering for Agent Systems

The Grid is a large-scale computer system that is capable of coordinating resources that are not subject to centralised control, whilst using standard, open, general-purpose protocols and interfaces, and delivering non-trivial qualities of service. In this chapter, we argue that Grid applications very strongly suggest the use of agent-based computing, and we review key uses of agent technologies in Grids: user agents, able to customize and personalise data; agent communication languages offering a generic and portable communication medium; and negotiation allowing multiple distributed entities to reach service level agreements. In the second part of the chapter, we focus on Grid service discovery, which we have identified as a prime candidate for use of agent technologies: we show that Grid-services need to be located via personalised, semantic-rich discovery processes, which must rely on the storage of arbitrary metadata about services that originates from both service providers and service users. We present UDDI-MT, an extension to the standard UDDI service directory approach that supports the storage of such metadata via a tunnelling technique that ties the metadata store to the original UDDI directory. The outcome is a flexible service registry which is compatible with existing standards and also provides metadata-enhanced service discovery.

ADELFE: a methodology for adaptive multi-agent systems engineering

Adaptive software is used in situations where either the environment is unpredictable or the system is open. This paper presents a methodology named ADELFE, which is led by the Rational Unified Process (RUP) but is devoted to software engineering of adaptive multi-agent systems. ADELFE guarantees that the software is developed according to the AMAS theory1. We focus this presentation on the additions of ADELFE regarding the three first core workflows of the RUP. Therefore, during the requirements phase, the environment of the studied system must be defined and characterized. Then, in the analysis phase, the engineer is guided to decide to use adaptive multi-agent technology and to identify the agents through the system and the environment models. Finally, the design workflow of ADELFE must provide the cooperative agent?s model and helps the developer to define the local agents? behavior. We illustrate the methodology by applying it to a case study: a timetable design.

Self-organization in multi-agent systems

This paper is the synthesis of joint work realised in a technical forum group within the AgentLink III NoE framework, which elaborated on issues concerning self-organization and emergence in multi-agent systems (MAS). The work concluded on a common definition of the concepts of self-organization and emergence in MAS and the associated properties and characteristics. Also it developed towards an approach for selecting self-organization mechanisms using a number of selected reference case studies and a set of evaluation criteria.

The AMAS theory for complex problem solving based on self-organizing cooperative agents

In this paper, we present an approach for the design of complex adaptive systems, based on adaptive multi-agent systems and emergence. We expound the AMAS theory (Adaptive Multi-Agent Systems) and its technical working. This theory gives local agent design criteria so as to enable the emergence of an organization within the system and thus, of the global function of the system. We also present the theorem of functional adequacy witch ensures that a cooperative self organizing system performs a suitable work. Applications of this theory in the multi-agent system framework led us to define the architecture and a general algorithm for cooperative agents. The originality of our approach lies in the very generic manner our re-organization rules work and that they are completely independent from the function the system has to compute.

A study of some multi-agent meta-models

Several agent-oriented methodologies have been proposed over the last few years. Unlike the object-oriented domain and unfortunately for designers, most of the time, each methodology has its own purposes and few standardization works have been done yet, limiting the impact of agent design on the industrial world. By studying three existing methodologies - ADELFE, Gaia and PASSI - and the concepts related to them, this paper tries to find a means to unify their meta-models. Comparing a certain number of features at the agent or system level (such as the agent structure, its society or organization, its interactions capacities or how agents may be implemented) has enabled us to draw up a first version of a unified meta-model proposed as a first step toward interoperability between agent-oriented methodologies.

Spray computers: Explorations in self-organization

We envision a future in which clouds of microcomputers can be sprayed in an environment to provide, by spontaneously networking with each other, an endlessly range of futuristic applications. However, beside the vision, spraying may also act as a powerful metaphor for a range of other scenarios that are already under formation, from ad hoc networks of embedded and mobile devices to worldwide distributed computing. After having detailed the different spray computers scenarios and their applications, this paper discusses the issues related to the design and development of spray computer applications, issues which call for novel autonomic approaches exploiting self-organization as first-class tools. Finally, this paper presents the key research efforts being taken in the area and attempts at defining a rough research agenda.

The ADELFE Methodology

This paper presents a method named ADELFE, which is led by the Rational Unified Process but is devoted to software engineering of adaptive MAS. ADELFE guarantees that the software is developed according to the AMAS theory. We focus this presentation on the four first core workflows of the RUP. Therefore, in the preliminary requirements an agreement on what the system has to do must be reached. During the final requirements phase, the environment of the studied system must be defined and characterized. Then, in the analysis phase, the engineer is guided to decide to use adaptive multiagent technology and to identify the agents through the system and the environment models. Finally, the design workflow of ADELFE must provide the cooperative agent’s model and helps the developer to define the local agents’ behavior. We illustrate the methodology by applying it to a case study: a timetable design.

Engineering Systems Which Generate Emergent Functionalities

Complexity of near future and even nowadays applications is exponentially increasing. In order to tackle the design of such complex systems, being able to engineer self-organising systems is a promising approach. This way, the whole system will autonomously changes its behaviour as its parts locally reorganise themselves, always providing an adapted function. This paper proposes to focus on engineering such systems generating emergent functionalities. We will first define two important concepts to take into account in such a context: Emergence and Self-Organisation. Building on these two concepts, we will highlight three main challenges researchers have to cope with: (i)how to control the system at the macro level by only focusing on the design of agents at the micro level, (ii)what kind of tools, models and guides are needed to develop such systems in order to help designers and (iii)how validation of such systems can be achieved? Each of these three challenges will be explained and positioned in regard to the main existing approaches. Our solutions combining emergence and self-organisation will be expounded for each challenge.

Spray computers: frontiers of self-organization for pervasive computing

We envision a future in which clouds of microcomputers can be sprayed in an environment to provide, by spontaneously networking with each other, an endlessly range of futuristic applications. However, beside the vision, spraying may also act as a powerful metaphor for scenarios such as ad-hoc networks and P2P computing. In this paper we: detail the different spray computers scenarios and their applications; discuss the issues related to the design and development of spray computer applications, calling for novel approaches exploiting self-organization and emergent behaviors as first-class tools; present the key research efforts being taken in the area; try to define a research agenda.

Enhancing self-organising emergent systems design with simulation

Nowadays, challenge is to design complex systems that evolve in changing environments. Multi-agent systems (MAS) are an answer to implement them and many agent-oriented methodologies are proposed to guide designers. Self-organisation is a promising paradigm to make these systems adaptive: the collective function arises from the local interactions and the system design becomes thus bottom-up. The difficulty rests then in finding the right behaviours at the agent-level to make the adequate global function emerge. The aim of this paper is to show how simulation can help designers to find these correct behaviours during the design stage: by simulating a simplified system and observing it during execution, a designer can modify and improve the behaviour of agents. A model of cooperative agents was implemented under the SeSAm platform in order to be integrated into ADELFE, an agent-oriented methodology dedicated to adaptive MAS (AMAS). This model is described here and applied to show how the behaviour of a simple ecosystem can be improved.