Abstract
This paper proposes a social networking perspective on the e-manufacturing area. A short justification of the social network-perspective as applied to manufacturing organizations is made, focusing on methods and theoretical approaches. Then, it is speculated how social networking can be a paradigm for the management of networks of manufacturing enterprises. The management relationship (fostering collaboration and cooperation) and their support through new information systems architectures are the key issues. Finally, some research directions are discussed, focussing on new engineering paradigms.

Abstract
This paper reviews relevant aspects of the formation and dissolution of interorganizational networks (ION) aiming at define requirements for systems managing knowledge networks in such environments. Firstly, the concept of networking and virtual organizing is reviewed. Then a major work on formation of ION is analysed and some conclusions are drawn regarding the design of ION. Finally, the requirements for knowledge management systems in the formation and dissolution of ION are discussed.

Abstract
This paper presents an approach to the identification of requirements for the implementation of e-business solutions in small and medium sized enterprises (SME). The approach is based oil the so-called reference models whose main purpose is to guide the process of deriving the detailed requirements for business processes and information systems support, regarding e-business activities. Firstly, an overview of the particular aspects and main difficulties of the adoption of e-business by SME is presented. This overview justifies the methodology for the implementation of e-business in SME, developed within the EC funded project MEDIAT-SME, shortly described here. Next, it is focused a particular aspect of this methodology, the reference models approach, followed by an example of its application on a real SME. Finally, the advantages and difficulties of the approach are discussed.

Abstract
The main purpose of this paper is to present a preliminary study on the impact of stratospheric ozone on tropospheric ozone levels under specific atmospheric dynamical conditions. It is well accepted that stratospheric ozone can be the source of part of the tropospheric ozone. Previous studies indicate that the mechanism responsible for this ozone intrusion occurs generally in several steps or just in a single step, usually associated with strong upward motion. In the first part of this paper, the methodology used in order to identify particular short-term episodes, potentially associated to the abovementioned phenomenon, is presented. Several episodes have been studied occurring during 14 years of ozone data collection, recorded by the Portuguese ozone network. Then, an analysis of the dynamical atmospheric conditions associated to previously identified episodes have been developed in order to verify the possibility of stratospheric contribution for the observed ozone level in each episode. Two of these episodes show a relatively good relationship between synoptical patterns related to stratospheric intrusions and backward trajectories. For these cases, the possibility of stratospheric origin should not be discarded before further study is developed.

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.