物件導向軟體之架構(Object-Oriented Software Construction)探討

An Introduction to MultiAgent Systems.

Systems and methods for navigating hypermedia using multiple coordinated input/output device sets. Disclosed systems and methods allow a user and/or an author to control what resources are presented on which device sets (whether they are integrated or not), and provide for coordinating browsing activities to enable such a user interface to be employed across multiple independent systems. Disclosed systems and methods also support new and enriched aspects and applications of hypermedia browsing and related business activities.

Method and apparatus for browsing using multiple coordinated device sets

Systems composed of interacting autonomous agents offer a promising software engineering approach for developing applications in complex domains. However, this multiagent system paradigm introduces a number of new abstractions and design/development issues when compared with more traditional approaches to software development. Accordingly, new analysis and design methodologies, as well as new tools, are needed to effectively engineer such systems. Against this background, the contribution of this article is twofold. First, we synthesize and clarify the key abstractions of agent-based computing as they pertain to agent-oriented software engineering. In particular, we argue that a multiagent system can naturally be viewed and architected as a computational organization, and we identify the appropriate organizational abstractions that are central to the analysis and design of such systems. Second, we detail and extend the Gaia methodology for the analysis and design of multiagent systems. Gaia exploits the aforementioned organizational abstractions to provide clear guidelines for the analysis and design of complex and open software systems. Two representative case studies are introduced to exemplify Gaia's concepts and to show its use and effectiveness in different types of multiagent system.

/pdf/developing-multiagent-systems-the-gaia-methodology-3qm0mwov2h.pdf

Developing multiagent systems: The Gaia methodology

Method and Apparatus for Browsing Using Alternative Linkbases

Mobile agents offer much promise, but agent mobility and Internet openness make coordination more difficult. Mobile Agent Reactive Spaces (MARS), a Linda-like coordination architecture with programming features, can handle a heterogeneous network while still allowing simple and flexible application design.

/pdf/mars-a-programmable-coordination-architecture-for-mobile-217c1rjcgq.pdf

MARS: a programmable coordination architecture for mobile agents

Internet applications face challenges that mobile agents and the adoption of enhanced coordination models may overcome. Each year more applications shift from intranets to the Internet, and Internet-oriented applications become more popular. New design and programming paradigms call help harness the Web's potential. Traditional distributed applications assign a set of processes to a given execution environment that, acting as local-resource managers, cooperating a network-unaware fashion. In contrast, the mobile-agent paradigm defines applications as consisting of network-aware entities-agents-which can exhibit mobility by actively changing their execution environment, transferring themselves during execution. The authors propose a taxonomy of possible coordination models for mobile-agent applications, then use their taxonomy to survey and analyze resent mobile-agent coordination proposals. Their case study, which focuses on a Web-based information-retrieval application, helps show that the mobility of application components and the distribution area's breadth can create coordination problems different from those encountered in traditional distributed applications.

Mobile-agent coordination models for Internet applications

The paper surveys several coordination models for mobile agent applications and outlines the advantages of uncoupled coordination models based on reactive blackboards. On this base, the paper presents the design and the implementation of the MARS system, a coordination tool for Java-based mobile agents. MARS defines Linda-like tuple spaces that can be programmed to react with specific actions to the accesses made by mobile agents.

Reactive Tuple Spaces for Mobile Agent Coordination

The design and development of Internet applications requiring dynamic and possibly mobile access to Internet resources can take advantage of an approach based on autonomous mobile agents. However, mobility introduces peculiar issues related to the modeling and management of the agents' coordination activities. This paper introduces context-dependent coordination as a framework for the design and development of Internet applications based on mobile agents, and shows how it can be supported by a proper coordination infrastructure. Context-dependent coordination is centered on the notion of programmable coordination media, as the software abstraction via which an agent in an Internet site can access to local resources and coordinate with local agents. Programmability stems from the fact that the behavior of the media can be fully configured to influence agents' coordination activities. This enables local administrators to configure coordination media so as to enact site-dependent coordination policies, and mobile agents to configure the accessed coordination media to obtain an application-dependent behavior of the media themselves. Several application examples shows that exploiting context-dependent coordination promotes a clear separation of concerns in design and development, and can make applications more modular and easier to be maintained. The MARS system is assumed as an exemplar coordination infrastructure to clarify the concepts expressed and to show their actual implementation.

/pdf/engineering-mobile-agent-applications-via-context-dependent-1z2j12a57v.pdf

Engineering mobile agent applications via context-dependent coordination

Software systems operating in open-ended and unpredictable environments have to become autonomic, i.e., capable of dynamically adapting their behavior in response to changing situations. To this end, key research issues include: (i) framing the schemes that can facilitate components (or ensembles of) to exhibit self-adaptive behaviors, (ii) identifying mechanisms to enable components or ensembles to self-express the most suitable adaptation scheme, and (iii) acquiring the proper degree of self-awareness to enable putting in action self-adaptation and self-expression schemes. In this position paper, with the help of a representative case study, we frame and discuss the above issues, survey the state of the art in the area, and sketch the main research challenges that will be faced in the ASCENS project towards the definition of a fully-fledged framework for autonomic services.

/pdf/on-self-adaptation-self-expression-and-self-awareness-in-30fvhftqqn.pdf

Giacomo Cabri

Papers

MARS: a programmable coordination architecture for mobile agents

Mobile-agent coordination models for Internet applications

Reactive Tuple Spaces for Mobile Agent Coordination

Engineering mobile agent applications via context-dependent coordination

On Self-Adaptation, Self-Expression, and Self-Awareness in Autonomic Service Component Ensembles