Abstract
In this paper, the Unit Commitment (UC) problem is presented and solved, following an innovative approach based on a metaheuristic procedure. The problem consists on deciding which electric generators must be committed, over a given planning horizon, and on defining the production levels that are required for each generator, so that load and spinning reserve requirements are verified, at minimum production costs. Due to its complexity, exact methods proved to be inefficient when real size problems were considered. Therefore, heuristic methods have for long been developed and, in recent years, metaheuristics have also been applied with some success to the problem. Methods like Simulated Annealing, Tabu Search and Evolutionary Programming can be found in several papers, presenting results that are sufficiently interesting to justify further research in the area. In this paper, a resolution framework based on GRASP - Greedy Randomized Adaptive Search Procedure - is presented. To obtain a general optimisation tool, capable of solving different problem variants and of including several objectives, the operations involved in the optimisation process do not consider any particular characteristics of the classical UC problem. Even so, when applied to instances with very particular structures, the computational results show the potential of this approach.

Abstract
Capacity analysis and planning plays a key role in the operational performance and levels of customer services of a company. Traditional capacity analysis and planning systems have become inadequate in the face of several emerging manufacturing paradigms. One such paradigm is the production in distributed enterprise networks, consisting of subsets of autonomous production units within supply chains working in a collaborative and coordinated way. In these distributed networks, capacity analysis and planning becomes a complex task, especially because it is performed in a heterogeneous environment where the performance of individual manufacturing sites and of the network as a whole should be simultaneously considered. Therefore, the use of information system solutions is desirable in order to support effective and efficient planning decisions. Nevertheless, it seems that there is a lack of a clear definition of the most important requirements that must be met by supporting solutions. This paper attempts to identify some general requirements of a decision support system to be used for capacity analysis and planning in enterprise networks. Adaptability of capacity models, computational efficiency, monitoring mechanisms, support for distributed order promising, and integration with other systems, are some important requirements identified.

Abstract
There is currently an increasing interest in exploring the opportunities for competitive advantage that can be gained by reinforcing core competencies and innovative capabilities through networks of industrial and business partners. This paper firstly identifies some of the gaps that exist within current information systems that claim to support eBusiness and eWork in networked enterprises and describes some of the general requirements of distributed and decentralised information systems for companies operating in networks. It goes on to cover some principles for the design of a distributed IS providing an advanced infrastructure to support general co-operation, particular methodologies for co-operative and collaborative planning and guidelines for network set-up and support. The present work is one of the areas currently being delivered as part of the Europe-an IST consortium called Co-OPERATE. A distributed and decentralised information system, based on an architecture of agents and extensively using the internet, is being designed and implemented as a means to provide new and more powerful decision support tools for networked enterprises.

Abstract
This paper describes an approach to the technical and organisational design of networked (and virtual) enterprises using a social actors network perspective. The goal is to outline a set of methods, tools and models that support a more effective analysis, design, implementation and (re)configuration of of the organisational structure and information systems supportting networks of enterprises. This paper introduces the social actors network concept, as well as its principles and scope, The application of social actors network in the domain of networked/virtual enterprises is explained. The paper concludes with an example derived from the EU supported Co-Operate IST project.

Abstract
This paper proposes a first version of a conceptual framework based on Social Actors Networks (SAN) to support the process of creation and configuration of Networked and Virtual Enterprises (N/VE). The concept of SAN is explained and applied in the context of N/VE, highlighting the potential benefits in the analysis and specification of agent based information systems. This approach is partially being tested in a distributed Decision Support System, designed around a flexible and robust agent-based information system architecture.

Abstract
This paper describes an application of genetic algorithms to the bus driver scheduling problem. The application of genetic algorithms extends the traditional approach of Set Covering/Set Partitioning formulations, allowing the simultaneous consideration of several complex criteria. The genetic algorithm is integrated in a DSS but can be used as a very interactive tool or a stand-alone application. It incorporates the user's knowledge in a quite natural way and produces solutions that are almost directly implemented by the transport companies in their operational planning processes. Computational results with airline and bus crew scheduling problems from real world companies are presented and discussed.