Browsing by Author "Santos, Jorge"
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- Classification Performance of Multilayer Perceptrons with Different Risk FunctionalsPublication . Silva, Luís; Santos, Jorge; Marques de Sá, JoaquimIn the present paper we assess the performance of information-theoretic inspired risks functionals in multilayer perceptrons with reference to the two most popular ones, Mean Square Error and Cross-Entropy. The information-theoretic inspired risks, recently proposed, are: HS and HR2 are, respectively, the Shannon and quadratic Rényi entropies of the error; ZED is a risk reflecting the error density at zero errors; EXP is a generalized exponential risk, able to mimic a wide variety of risk functionals, including the information-thoeretic ones. The experiments were carried out with multilayer perceptrons on 35 public real-world datasets. All experiments were performed according to the same protocol. The statistical tests applied to the experimental results showed that the ubiquitous mean square error was the less interesting risk functional to be used by multilayer perceptrons. Namely, mean square error never achieved a significantly better classification performance than competing risks. Cross-entropy and EXP were the risks found by several tests to be significantly better than their competitors. Counts of significantly better and worse risks have also shown the usefulness of HS and HR2 for some datasets.
- Estudos da Deglutição por Videofluoroscopia: Papel do Terapeuta da FalaPublication . Santos, JorgeOs estudos da deglutição por videofluoroscopia (EDVF) são considerados uma avaliação de referência por diversos centros de estudos da deglutição. É um método radiológico que permite observar a dinâmica das estruturas envolvidas na deglutição nas fases preparatória oral, faríngea e esofágica. Este trabalho pretende descrever o contributo do terapeuta da fala (TF) na realização de EDVF em casos de alterações orofaríngeas. Para tal foi efetuada uma revisão de literatura sobre o tema, tendo por base diferentes guidelines publicadas e artigos científicos na área, assim como a experiência clínica adquirida neste domínio no Hospital Privado da Trofa SA. Será enquadrado o papel do TF na realização dos EDVF, descrita a metodologia da avaliação (técnica, materiais e métodos), segurança e proteção radiológica, indicações, limitações e contra indicações desta avaliação instrumental, aspetos fisiológicos e fisiopatológicos analisados. O TF desempenha um papel fundamental na avaliação e intervenção nas alterações orofaríngeas da deglutição. O conhecimento dos procedimentos, metodologias de realização e análise dos resultados da avaliação videofluoroscópica é fulcral para a capacitação e desenvolvimento de competências neste domínio dos Terapeutas da Fala (TFs) assim como para a divulgação do papel do TF na realização dos EDVF.
- Revenue management prlcing in Douro Hotels [Study Group Report]Publication . Correia, Elisete; Dias, Sónia; Ferreira, Fernanda A.; Moura, Ana; Nunes, Paula; Pereira, Maria Teresa Ribeiro; Santos, Jorge; Pereira, Carla Santos; Soares, Filomena Baptista; Soares, JoãoThe Douro Palace Hotel management wants to develop a software that helps them with the dynamic pricing of the hotel rooms. Revenue Management software is widely used for data analysis of demand and prices. However the hotel barely follows the software recommendations for pricing decisions, mainly due to the lack of understanding of the rationale and the inherent difficulty in validating pricing decisions. The hotel would like to have a reliable model in order to give to the manager an overview of the business and how to act to improve the sales. The questions raised at the study group are related to this. In this report, we present two distinct methodologies to address the hotel request. The first approach is excel based and more practically oriented towards to be an immediate help of the current pricing decisions. A second approach is more formal, mathematically speaking, but requires a more time consuming implementation. It is based on a recent operations management/operations research paper. On short term plan, we propose the implementation of an automatic generation of excel files that will enable Douro Palace Hotel react more often/finely to the competition pricing. A thorough statistical analysis of the Demand function and the corresponding segmentation is also required - for simulation purposes or decision support. We think that Douro Palace Hotel should differentiate prices more often and promptly (both upwardly and downwardly) depending on the perception of the demand and the competitors prices. On a long term plan, we propose the implementation of more sophisticated approaches, mathematically speaking, such as the one described in this report.
- The verification of temporal KBS: SPARSE - a case study in power systemsPublication . Santos, Jorge; Vale, Zita; Serôdio, Carlos; Ramos, CarlosIn this paper we present VERITAS, a tool that focus time maintenance, that is one of the most important processes in the engineering of the time during the development of KBS. The verification and validation (V&V) process is part of a wider process denominated knowledge maintenance, in which an enterprise systematically gathers, organizes, shares, and analyzes knowledge to accomplish its goals and mission. The V&V process states if the software requirements specifications have been correctly and completely fulfilled. The methodologies proposed in software engineering have showed to be inadequate for Knowledge Based Systems (KBS) validation and verification, since KBS present some particular characteristics. VERITAS is an automatic tool developed for KBS verification which is able to detect a large number of knowledge anomalies. It addresses many relevant aspects considered in real applications, like the usage of rule triggering selection mechanisms and temporal reasoning.