Structured objects are items with defined properties that are to be represented in a computer system. Research in Knowledge Representation (KR) and in Database Design (DB) has produced languages for describing structured objects. Although different in the particular means for defining properties, both areas share the goal of representing a part of the world in a structured way. Moreover, the rise of object-centred formalisms in the last decade has significantly influenced the convergence of languages.

Distributed Artificial Intelligence systems, in which multiple agents interact to improve their individual performance and to enhance the systems' overall utility, are becoming an increasingly pervasive means of conceptualising a diverse range of applications. As the discipline matures, researchers are beginning to strive for the underlying theories and principles which guide the central processes of coordination and cooperation. Here agent communities are modelled using a distributed goal search formalism, and it is argued that commitments (pledges to undertake a specific course of action) and conventions (means of monitoring commitments in changing circumstances) are the foundation of coordination in multi-agent systems. An analysis of existing coordination models which use concepts akin to commitments and conventions is undertaken before a new unifying framework is presented. Finally, a number of prominent coordination techniques which do not explicitly involve commitments or conventions are reformulated in these terms to demonstrate their compliance with the central hypothesis of this paper.

Assuring the reliability of knowledge-based systems has become an important issue in the development of the knowledge engineering discipline. There has been a workshop devoted to these topics at most of the major AI conferences (IJCAI, AAAI and ECAI) for the last five years, and the 1994 European Conference on Artificial Intelligence (ECAI-94) in Amsterdam was no exception. The focus of the meeting was on validation techniques for KBS, where validation is defined as the process of determining if a KBS meets its users' requirements; implicitly, validation includes verification, which is the process of determining if a KBS has been constructed to comply with certain formally-specified properties, such as consistency and irredundancy. The Amsterdam workshop was an intimate meeting, and the fifteen attendees were predominantly from European institutions. In spite of—or perhaps because of—this intimacy, the workshop succeeded in highlighting many of the significant trends and issues within its area of concern. The purpose of this short article is to review the trends and issues in question, drawing upon the contributions made during the workshop.

A central area of application for knowledge-based systems is for giving consultative advice to the user. Such systems engage the user in a dialogue in the process of collecting enough information to be able to infer a conclusion from the knowledge base. Traditionally, then, the main initiative in the consultation process has been allocated to the system

The purpose of this paper is to evaluate and compare three of the most powerful expert system tools available: KEE from Intellicorp, Knowledge Craft from The Carnegie Group Inc., and ART from Inference Corporation.

These three tools are industrial development environments which are fully supported and well beyond research prototypes. They were implemented on Lisp machines initially, but will soon be available on conventional computers. The three systems are very flexible and offer many ways of representing knowledge.

The first part of the paper is a technical overview of each tool. The second part presents their common features. The third part discusses the advantages and drawbacks of each, according to types of application.

This work has been partially sponsored by the Commission of the European communities within the Esprit Project 932 entitled ‘Knowledged-based Real-Time supervision in Computer Integrated Manufacturing’. We are grateful to Didier Gaget-Soufflot (Graphael, France) and Bernard Raust (CGE/TITN) for their participation in the evaluation of KEE and ART respectivily.

The relentless growth of the computer industry over more than 30 years has been driven on by a series of major innovations. High-level languages; solid-state logic; compatible machine ranges; disk storage; time-sharing; data communications; virtual machine architectures; the use of LSI and solid-state memory; text processing; personal computers; sucessful packaged software; each advance in its turn has opened up new markets and set off a new spurt of expansion. A vital conclusion of this study is that expert systems promise to be another such major innovation.