This article presents the STROBE model: both an agent representation and an agent communication model based on a social approach, that means interaction centred. This model represents how agents may realise the interactive, dynamic generation of services on the Grid. Dynamically generated services embody a new concept of service implying a collaborative creation of knowledge i.e. learning; services are constructed interactively between agents depending on a conversation. The approach consists of integrating selected features from Multi-Agent Systems and agent communication, language interpretation in applicative/functional programming and e-learning/human-learning into a unique, original and simple view that privileges interactions, yet including control. The main characteristic of STROBE agents is that they develop a language (environment + interpreter) for each of their interlocutors. The model is inscribed within a global approach, defending a shift from the classical algorithmic (control based) view to problem solving in computing to an interaction-based view of Social Informatics, where artificial as well as human agents operate by communicating as well as by computing. The paper shows how the model may not only account for the classical communicating agent approaches, but also represent a fundamental advance in modelling societies of agents in particular in Dynamic Service Generation scenarios such as those necessary today on the Web and proposed tomorrow for the Grid. Preliminary concrete experimentations illustrate the potential of the model; they are significant examples for a very wide class of computational and learning situations.

We sketch a variant of the KGP agent model tailored to support service composition in service-oriented architectures. This allows to handle: user requirements, abstract and concrete workflows, possibly with annotations, inter-agent communication for supporting negotiation and persuasion, consultation of registries. We identify argumentation as core for Service-Oriented Architectures, and ground our work in the context of three concrete scenarios: e-procurement, earth observation, and business migration.

Abstract. We present an argumentation-based approach to design and realise agents that can support the selection and composition of services in distributed environments, such as service-oriented architectures and grids. The choice of services (for selection or for composition) is equated to decisions. The agents are equipped with beliefs, in the form of (possibly con icting) defeasible rules, goals and alternative decisions. Beliefs, goals, decisions may be ranked according to speci ed preferences. We show how beliefs and preferences can be taken into account to support the decisionmaking process of the agent, in order to achieve its goals. We deal with con icts and preferences by using assumption-based argumentation, an existing computational-logic-based argumentation framework, that has already been proven to be an e ective tool for many applications of argumentation. 1

Resource discovery is a key issue for Grid systems in which applications are composed of hardware and software resources that need to be located. Classical approaches to Grid resource discovery are either centralized or hierarchical and will prove inefficient as the scale of Grid systems rapidly increases. On the other hand, the Peer-to-Peer (P2P) paradigm emerged as a successful model that achieves scalability in distributed systems. One possibility would be to borrow existing methods from the P2P paradigm and to adopt them to Grid systems taking into consideration the existing differences. Several such attempts have been made during the last couple of years. This report aims to serve as a review of the most promising Grid systems that use P2P techniques to facilitate resource discovery in order

Abstract. We present an approach for development of Grid resource management tools, where we put into practice internationally established high-level views of future Grid architectures. The approach addresses fundamental Grid challenges and strives towards a future vision of the Grid where capabilities are made available as independent and dynamically assembled utilities, enabling run-time changes in the structure, behavior, and location of software. The presentation is made in terms of design heuristics, design patterns, and quality attributes, and is centered around the key concepts of co-existence, composability, adoptability, adaptability, changeability, and interoperability. The practical realization of the approach is illustrated by five case studies (recently developed Grid tools) high-lighting the most distinct aspects of these key concepts for each tool. The approach contributes to a healthy Grid ecosystem that promotes a natural selection of “surviving ” components through competition, innovation, evolution, and diversity. In conclusion, this environment facilitates the use and composition of components on a per-component basis. 1

During the last decade there has been a huge interest in Grid technologies, and numerous Grid projects have been initiated with various visions of the Grid. While all these visions have the same goal of resource sharing, they differ in the functionality that a Grid supports, the grid characterisation, programming environments, etc. In this paper we present a new Grid system dedicated to deal with data issues, called DGET (Data Grid Environment and Tools). DGET is characterized by its peer-topeer communication system and entity-based architecture, therefore, taking advantage of the main functionality of both systems; P2P and Grid. DGET is currently under development and a prototype implementing the main components is in its first phase of testing. In this paper we limit our description to the system architectural features and to the main differences with other systems.

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Abstract. It has been suggested that utilization of autonomous software agents in computational Grids may deliver the needed functionality to speed-up Grid adoption. I our recent work we have outlined an approach in which agent teams facilitate Grid resource brokering and management. One of the interesting questions is how to manage trust in such a system. The aim of this paper is to outline our proposed solution.

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With the emergence of new paradigms for computing, such as peer-to-peer technologies, grid computing, autonomic computing and other approaches, it is becoming increasingly natural to view large systems in terms of the services they