Abstract

Abstract
In a competitive electricity market, generation companies have to maximize their profits selecting the best strategy. This paper is on the problem of short-term hydro scheduling, particularly concerning a head-sensitive hydro chain. We propose a method based on nonlinear programming that considers power generation a function of water discharge and also of the head. The proposed method provides a higher profit for the company in comparison with classical optimization methods based on linear programming that ignores head dependence. Numerical results based on a realistic cascaded hydro chain show that this method is adequate for dealing with head-sensitive hydro chains.

Abstract
Many real life problems require the classification of items in naturally ordered classes. These problems are traditionally handled by conventional methods for nominal classes, ignoring the order. This paper introduces a new training model for feedforward neural networks, for multiclass classification problems, where the classes are ordered. The proposed model has just one output unit which takes values in the interval [0,1]; this interval is then subdivided into K subintervals (one for each class), according to a specific probabilistic model. A comparison is made with conventional approaches, as well as with other architectures specific for ordinal data proposed in the literature. The new model compares favourably with the other methods under study, in the synthetic dataset used for evaluation.

Abstract
The possibility of fabricating efficient optical amplifiers in LiNbO3, realized by localization of the dopant on surface areas was theoretically evaluated and the feasibility of fabricating efficient amplifiers in such doped structures was experimentally verified. The model of amplifiers based on 3-level laser systems realized by local doping incorporates dopant localization, the influence of the interaction length, as well as that of the effective pump area and of the pump power in the amplifier performance. It was verified that localized doping allows optimization of amplifier performance through adjustment of the active region geometry to the mode intensity profile. The experimental results confirmed that the width of the metal stripe deposited on the surface must be optimized so that gain is maximum, for a given value of the pump power. It was experimentally demonstrated that transverse localization of the active ions reduces the threshold pump power, which may be relevant for realization of integrated lasers in Er:LiNbO3.

Abstract

Abstract
New forms of collaboration emerged as response to transformations of the business environment and the rapid information and communication technologies developments. In this context, collaborative networks rise as a powerful mechanism to achieve strategic objectives in a time response, quality and cost effective manner. The aim of this paper is to present the most relevant challenges concerning collaborative networks paradigm analysis, and to advance a multi-perspective approach on collaborative networks (technological, semantic, social and business perspective), emphasizing the importance of the business view that allows collaborative networks to be regarded as combinations of inter- and intra-enterprise business processes. Balance Scorecard is seen as a powerful tool which can guarantee the strategic and business goal alignment within the network.