Abstract

Abstract

Abstract
This paper is concerned with the formalization of a automated contracting mechanism that enables a society of cooperative resource allocation agents to negotiate rationally in a self-interested meta-society. Such environments induce agents to adopt different social behaviors according to the negotiation partner. This problem may be solved by taking an economic perspective in all the decisions, namely, by using utility based agents, through the use of marginal utility calculations, and defining dynamically the market extent for a task. The risk attitude and reactivity of each agent can be parameterized in order to achieve different negotiation strategies. The framework presented in this paper can be applied in a wide variety of situations, ranging from electronic commerce on virtual economic markets, to load distribution problems. © Springer-Verlag Berlin Heidelberg 1997.

Abstract
This paper describes a preliminary experience in trying to improve the communication and to reach language agreements in the context of a large R&D trans-national project, comprising partners with different academic and industrial cultures. This kind of projects has difficulties in that, besides cultural and language problems, the project teams undertake work largely by themselves, with reduced interaction with each other. The use of ontologies has a great potential in reducing those problems. Within this research work our goal is to extend the communication role of an ontology towards the mediation of the development actors ''world views''. In doing so, we intend to improve the engineering of an intrinsically complex software system, particularly in the requirements identification, system specification and system design phases, overcoming some of the referred difficulties. It is presented an extract of the Virtual Enterprise ontology currently under construction, focusing in some core definitions relevant for the purpose of developing a distributed planning and control software system. An example concerning the development of such a system is described in older to demonstrate the usefulness of the ontology based systems development.

Abstract
The environmental management domain is vast and encompasses many identifiable activities: impact assessment, planning, project evaluation, etc. In particular, this paper focusses on the modelling of the project evaluation activity. The environmental decision support system under development aims to provide assistance to project developers in the selection of adequate locations, guaranteeing the compliance with the applicable regulations and the existing development plans as well as satisfying the specified project requirements. The inherent multidisciplinarity features of this activity lead to the adoption of the Multi-Agent paradigm, and, in particular, to the modelling of the involved agencies as a community of cooperative autonomous agents, where each agency contributes with its share of problem solving to the final system's recommendation. To achieve this behaviour the many conclusions of the individual agencies have to be justifiably accommodated: not only they may differ, but can be interdependent, complementary, irreconcilable, or simply, independent. We propose different solutions (involving both local and global consistency) to support the adequate merge of the distinct perspectives that inevitably arise during this type of decision making.

Abstract
In this paper a combined Monte Carlo-extended equal area formulation for the transient security assessment of a multimachine power system is proposed. This approach evaluates a probabilistic measure of the transient stability, instead of just a particular response to a specified disturbance. Due to the large number of calculations required, the application of the extended equal area criteria reduces drastically the computing time, since it allows to evaluate the critical clearing times and the stability margins without solving numerically the differential motion equations. The probabilistic software package TRANsySTEM, developed by the authors to study the transient security of a multimachine system, is applied to a test network. During the simulation time, the occurrence of disturbances and the subsequent protective actions are assumed as a stochastic process. Finally, the obtained results are discussed and some conclusions that provide a valuable contribution to the understanding of the system dynamics are pointed out.