This paper provides an overview of research and development activities in the field of autonomous agents and multi-agent systems. It aims to identify key concepts and applications, and to indicate how they relate to one-another. Some historical context to the field of agent-based computing is given, and contemporary research directions are presented. Finally, a range of open issues and future challenges are highlighted.

The ability to rapidly locate useful on-line services (e.g. software applications, software components, process models, or service organizations), as opposed to simply useful documents, is becoming increasingly critical in many domains. Current service retrieval technology is, however, notoriously prone to low precision. This paper describes a novel service retrieval approached based on the sophisticated use of process ontologies. Our preliminary evaluations suggest that this approach offers qualitatively higher retrieval precision than existing (keyword and tablebased) approaches without sacrificing recall and computational tractability/scalability.

The ability to rapidly locate useful on-line services (e.g. software applications, software components, process models, or service organizations), as opposed to simply useful documents, is becoming increasingly critical in many domains. As the sheer number of such services increases it will become increasingly more important to provide tools that allow people (and software) to quickly find the services they need, while minimizing the burden for those who wish to list their services with these search engines. This can be viewed as a critical enabler of the `friction-free' markets of the `new economy'. Current service retrieval technology is, however, seriously deficient in this regard. The information retrieval community has focused on the retrieval of documents, not services per se, and has as a result emphasized keyword-based approaches. Those approaches achieve fairly high recall but low precision. The software agents and distributed computing communities have developed...

www.ced.tuc.gr/˜manolis Abstract. We define formally the data models WP, AWP and AWPS especially designed for the dissemination of textual information by distributed agent systems using communication languages such as KQML and FIPA-ACL. We also define the problems of satisfaction and filtering and point out that these problems are fundamental for the deployment of our models in distributed agent architectures appropriate for information dissemination. One such architecture currently under development in project DIET is sketched in some detail in this paper. Finally, we present algorithms for the problems of satisfaction and filtering, prove the correctness of these algorithms, and calculate their computational complexity. 1

This paper critically analyse the use of active databases as an enabling technology for result sharing as defined in the DAI literature.

Software security to protect mobile agent consists of lots of aspects like cryptography, access control and trust management, intrusion detection and tamper resistance, authentication and privacy, signature schemes, e-commerce, security analysis, mobile computing security etc. So, to design and develop security mechanisms for mobile agents against malicious hosts this paper identifies different kinds of attacks and relationships between them. Security objectives and requirements are analyzed with security measures taken to protect mobile code, state and data.