Abstract
An investigation on optical amplification in Ti waveguides in LiNbO3 doped with Er ions by thermal diffusion of thin metallic stripes is presented. The possibility of fabricating efficient optical amplifiers in LiNbO3 substrates realized by localization of the dopant on surface areas of the crystals was theoretically evaluated and the feasibility of fabricating efficient amplifiers in such doped structures was experimentally verified. It was concluded that the localized doping technique allows optimization of amplifier performance through adjustment of the active region geometry to the mode intensity profile.

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Abstract

Abstract
In a previous work, we presented system Ltree, a multivariate tree that combines a decision tree with a linear discriminant by means of constructive induction. We have shown that it performs quite well, in terms of accuracy and learning times, in comparison with other multivariate systems like LMDT, OC1, and CART. In this work, we extend the previous work by using two new discriminant functions: a quadratic discriminant and a logistic discriminant. Using the same architecture as Ltree we obtain two new multivariate trees Qtree and LgTree. The three systems have been evaluate on 17 UCI datasets. From the empirical study, we argue that these systems can be shown as a composition of classifiers with low correlation error. From a bias-variance analysis of the error rate, the error reduction of all the systems in comparison to a univariate tree, is due to a reduction on both components.

Abstract
This paper provides a description of a new approach for steady-state security evaluation, using fuzzy nearest prototype classifiers. The basic method has an offline training phase, used to design the fast classifiers for online purposes, allowing more than the two traditional security classes. A battery of these fuzzy classifiers, valid for a specific configuration of the network, is adopted to produce a global evaluation for all relevant single contingencies. An important feature of this approach is that it selects automatically the most appropriate number of security clusters for each selected contingency. Natural language labeling is also used to produce standardized sentences about the security level of the system, improving in this way the communication process between the system and the operator. The paper is completed by an example on a realistic model of the Hellenic Interconnected power system, where seven contingencies were simulated.

Abstract
An account is given on the joint time-frequency analysis (JTFA) and the short time-frequency transform algorithm in particular as an alternative technique for dynamic testing of analog to digital converters (ADCs). It is shown that this technique can lead to a significant improvement in ADC testing mainly due the possibility of using non-stationary signals allowing a more rapid test capable of analyzing even localized features.