DimDim a l'aula

Resultat del grup de treball CIFE-GI "Incorporació de les TIC a la docència" essent un espai d'intercanvi d'experiències i de promoció de la transferència d'activitats docents dutes a terme amb el suport de les TIC.Seguiment de la classe mitjaçant DimDi

Processing, traitement, processament

Un títol una mica estrany per a una lliçó inaugural, però que té una explicació simple: d’entrada tres paraules, que ens marcaran els tres apartats en què he dividit aquesta lliçó. I després tres idiomes, que em serviran per centrar cada un dels tres apartats i enllaçar-los entre ells, per fer de les parts un tot únic i coherent

Estimación de funciones no lineales en mezclas post-no lineales

This paper proposes a new method for blindly inverting a nonlinear mapping which transforms a sum of random variables. This is the case of post-nonlinear (PNL) source separation mixtures. The importance of the method is based on the fact that it permits to decouple the estimation of the nonlinear part from the estimation of the linear one. Only the nonlinear part is inverted, without considering on the linear part. Hence the initial problem is transformed into a linear one that can then be solved with any convenient linear algorithm. The method is compared with other existing algorithms for blindly approximating nonlinear mappings. Experiments show that the proposed algorithm outperforms the results obtained with other algorithms and give a reasonably good linearized dat

On cumulant techniques in speech processing

This paper analyzes applications of cumulant analysis in speech processing. A special focus is made on different second-order statistics. A dominant role is played by an integral representation for cumulants by means of integrals involving cyclic products of kernels

Post-Nonlinear Mixtures and Beyond

Although sources in general nonlinear mixturm arc not separable iising only statistical independence, a special and realistic case of nonlinear mixtnres, the post nonlinear (PNL) mixture is separable choosing a suited separating system. Then, a natural approach is based on the estimation of tho separating Bystem parameters by minimizing an indcpendence criterion, like estimated mwce mutual information. This class of methods requires higher (than 2) order statistics, and cannot separate Gaarsian sources. However, use of [weak) prior, like source temporal correlation or nonstationarity, leads to other source separation Jgw rithms, which are able to separate Gaussian sourra, and can even, for a few of them, works with second-order statistics. Recently, modeling time correlated s011rces by Markov models, we propose vcry efficient algorithms hmed on minimization of the conditional mutual information. Currently, using the prior of temporally correlated sources, we investigate the fesihility of inverting PNL mixtures with non-bijectiw non-liacarities, like quadratic functions. In this paper, we review the main ICA and BSS results for riunlinear mixtures, present PNL models and algorithms, and finish with advanced resutts using temporally correlated snu~s

Reduced scale feasibility of temperature rise tests in substation connectors

Due to the important increase of the power of electrical transmission and distribution grids expected for the following years, especially in developing countries such as Kenya, Brazil, Philippines or Mexico among others, that have planes of generating energy from clean sources far away from the centres of consumption [1] it becomes a matter of special importance adapting and developing new substation connectors’ testing methods according to the power and temperature regimes at which they are expected to work. The international normative frame of substation connectors established both by the International Electrotechnical Committee (IEC) [2] and the National Electrical Manufacturers Association (NEMA) [3] sets standardized tests for the evaluation of high voltage connectors. These tests are routinely done within the quality plans of the manufacturers. At the moment, testing of substation connectors –and in general switchgear and fittings- is time demanding and costly due to the energy consumed by such tests. The expectations for the following years are that the power consumption of these tests will not do nothing but grow due to expected increase of power of worldwide overhead lines. For instance, today temperature rise tests in substation connectors involve power ranges up to 100 kVA, which are applied in cycles that can last several weeks. These tests are only feasible in few laboratories and at a very high cost: temporary, monetary, energetic and environmental. For this reason, following the line of other technologies such as aeronautics, naval engineering, or automotive as well as other studies done in the field of electrical engineering specially related to the corona effect [4], this study proposes to develop a reduced scale test system to perform temperature rise tests for substation connectors. Both, a theoretical framework based on analytical formulas, finite element method (FEM) simulations and experimental data has been developed to conduct reduced scale temperature rise tests and to set the conditions at which they provide comparable results to those attained in the original scale tests. Firstly, two circular loops (original and reduced scale loops) composed of a power conductor and two terminal connectors were analysed. The aim of this first study was to determine in an easy and trustful way the voltage and current values to be applied in experimental reduced scale tests to achieve the same steady-state temperature as in the original scale temperature rise test. The scale relationship between tests was set in 1:1.8, although the method proposed in this study can deal with any other scale factor. This study was useful in order to have a first sight of the final results of the procedure using substation connectors.Postprint (published version

Martí i Pol traduït: Estudi de la correspondència entre el poeta i els traductors de la seva obra

La relació de Miquel Martí i Pol amb la traducció és estreta. D’una banda, l’exerceix com a traductor de Georges Arnaud, Claude Lévi-Strauss o Simone de Beauvoir; de l’altra, la seva producció poètica és objecte de traduccions a més de 15 idiomes. Amb aquest article ens proposem l’objectiu d’analitzar la correspondència entre el poeta i els seus torsimanys disponible al Fons Miquel Martí i Pol de Roda de Ter per tal de resseguir, en la mesura del possible, el grau de participació de l’autor rodenc en el procés de traducció de la seva obra a d’altres llengües.Miquel Martí i Pol had a tight relationship with translation. On the one hand, he translated into Catalan works from Georges Arnaud, Claude Lévi-Strauss or Simone de Beauvoir; on the other hand, his poetry has been translated into more than 15 languages. This article analyses the exchange of correspondence between the poet and his translators (available at Miquel Martí i Pol Documentary Collection in Roda de Ter) in order to evaluate the role of the poet in the translation process of his poems