Data mining techniques to support the classification of MV electricity customers

This paper describes a methodology that was developed for the classification of Medium Voltage (MV) electricity customers. Starting from a sample of data bases, resulting from a monitoring campaign, Data Mining (DM) techniques are used in order to discover a set of a MV consumer typical load profile and, therefore, to extract knowledge regarding to the electric energy consumption patterns. In first stage, it was applied several hierarchical clustering algorithms and compared the clustering performance among them using adequacy measures. In second stage, a classification model was developed in order to allow classifying new consumers in one of the obtained clusters that had resulted from the previously process. Finally, the interpretation of the discovered knowledge are presented and discussed.

A colonoscopia virtual no rastreio do cancro colo rectal

O cancro colo - rectal (CCR) é um problema de saúde mundial, estando associadas elevadas taxas de mortalidade e morbilidade. A maioria de CCR deriva de pólipos adenomatosos.. Um estudo retrospectivo, efectuado no serviço de Radiologia, dos achados imagiológicos típicos e atípicos, entre Janeiro de 2008 e Junho 2010. A Colonoscopia Virtual, apresenta uma sensibilidade elevada na detecção de lesões, com dimensão superior a 10mm, permitindo um diagnóstico precoce, é um exame rápido, pouco invasivo, não há necessidade de sedação e é efectuada em ambulatório.

A data-mining-based methodology for transmission expansion planning

In recent decades, all over the world, competition in the electric power sector has deeply changed the way this sector’s agents play their roles. In most countries, electric process deregulation was conducted in stages, beginning with the clients of higher voltage levels and with larger electricity consumption, and later extended to all electrical consumers. The sector liberalization and the operation of competitive electricity markets were expected to lower prices and improve quality of service, leading to greater consumer satisfaction. Transmission and distribution remain noncompetitive business areas, due to the large infrastructure investments required. However, the industry has yet to clearly establish the best business model for transmission in a competitive environment. After generation, the electricity needs to be delivered to the electrical system nodes where demand requires it, taking into consideration transmission constraints and electrical losses. If the amount of power flowing through a certain line is close to or surpasses the safety limits, then cheap but distant generation might have to be replaced by more expensive closer generation to reduce the exceeded power flows. In a congested area, the optimal price of electricity rises to the marginal cost of the local generation or to the level needed to ration demand to the amount of available electricity. Even without congestion, some power will be lost in the transmission system through heat dissipation, so prices reflect that it is more expensive to supply electricity at the far end of a heavily loaded line than close to an electric power generation. Locational marginal pricing (LMP), resulting from bidding competition, represents electrical and economical values at nodes or in areas that may provide economical indicator signals to the market agents. This article proposes a data-mining-based methodology that helps characterize zonal prices in real power transmission networks. To test our methodology, we used an LMP database from the California Independent System Operator for 2009 to identify economical zones. (CAISO is a nonprofit public benefit corporation charged with operating the majority of California’s high-voltage wholesale power grid.) To group the buses into typical classes that represent a set of buses with the approximate LMP value, we used two-step and k-means clustering algorithms. By analyzing the various LMP components, our goal was to extract knowledge to support the ISO in investment and network-expansion planning.

Zonal prices analysis supported by a data mining based methodology

A methodology based on data mining techniques to support the analysis of zonal prices in real transmission networks is proposed in this paper. The mentioned methodology uses clustering algorithms to group the buses in typical classes that include a set of buses with similar LMP values. Two different clustering algorithms have been used to determine the LMP clusters: the two-step and K-means algorithms. In order to evaluate the quality of the partition as well as the best performance algorithm adequacy measurements indices are used. The paper includes a case study using a Locational Marginal Prices (LMP) data base from the California ISO (CAISO) in order to identify zonal prices.

Health and psychosocial effects of flexible working hours

OBJECTIVE: To examine whether any impairments in health and social lives can be found under different kinds of flexible working hours, and whether such effects are related to specific characteristics of these working hours. METHODS: Two studies - a company based survey (N=660) and an internet survey (N=528) - have been conducted. The first one was a questionnaire study (paper and pencil) on employees working under some 'typical' kinds of different flexible working time arrangements in different companies and different occupational fields (health care, manufacturing, retail, administration, call centres). The second study was an internet-based survey, using an adaptation of the questionnaire from the first study. RESULTS: The results of both studies consistently show that high variability of working hours is associated with increased impairments in health and well-being and this is especially true if this variability is company controlled. These effects are less pronounced if variability is self-controlled; however, autonomy does not compensate the effects of variability. CONCLUSIONS: Recommendations for an appropriate design of flexible working hours should be developed in order to minimize any impairing effects on health and psychosocial well-being; these recommendations should include - besides allowing for discretion in controlling one's (flexible) working hours - that variability in flexible working hours should be kept low (or at least moderate), even if this variability is self-controlled.

Intelligent SCADA for load control

A supervisory control and data acquisition (SCADA) system is an integrated platform that incorporates several components and it has been applied in the field of power systems and several engineering applications to monitor, operate and control a lot of processes. In the future electrical networks, SCADA systems are essential for an intelligent management of resources like distributed generation and demand response, implemented in the smart grid context. This paper presents a SCADA system for a typical residential house. The application is implemented on MOVICON™11 software. The main objective is to manage the residential consumption, reducing or curtailing loads to keep the power consumption in or below a specified setpoint, imposed by the costumer and the generation availability.

Segurança na América do Sul: uma abordagem histórico-conceitual

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reabilitação de edifícios de habitação no Bairro da Mouraria em Lisboa

A Reabilitação Urbana é uma preocupação que afeta a maioria dos municípios portugueses. A degradação nosso património edificado da nossa memória, principalmente nos centros históricos, tornou-se um problema que urge resolver rapidamente. Na conjuntura que o país atravessa, com o excesso de construção nova que nos últimos anos inundou o mercado, a reabilitação assume-se como uma opção para a indústria da construção civil. No caso do Bairro da Mouraria, o esforço que o município tem vindo a desenvolver, que implica grandes investimentos e grande esforço financeiro, no difícil contexto económico do país, assume maior relevância. Esta dissertação debruça-se sobre o caminho percorrido, as condicionantes das soluções de projeto e do investimento na reabilitação no Bairro da Mouraria. E sobre os aspetos que envolvem esta atividade e conferem à recuperação do edificado um carácter especial, pois trata-se de um tipo de obra que se reveste de alguma imprevisibilidade, que pode mesmo levar a custos adicionais e à inviabilidade dos investimentos. O que justifica que para este tipo de obras tenha de haver uma atenção redobrada desde a fase do levantamento do edificado, das suas patologias, das obras a realizar, das soluções arquitetónicas e técnicas a adotar, passando pela fase de licenciamento do projeto, até à recuperação física dos edifícios. Pretende-se, também, apresentar algumas situações típicas de reabilitação de edifícios antigos, aprofundando-se as questões técnicas sobre as patologias mais correntes, a viabilidade económica das operações e enquadrando os principais fatores que têm retardado o processo.

Simulation of the Magnetic Induction Vector of a Magnetic Core to be Used in FFC NMR Relaxometry

This paper is a contribution for the assessment and comparison of magnet properties based on magnetic field characteristics particularly concerning the magnetic induction uniformity in the air gaps. For this aim, a solver was developed and implemented to determine the magnetic field of a magnetic core to be used in Fast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometry. The electromagnetic field computation is based on a 2D finite-element method (FEM) using both the scalar and the vector potential formulation. Results for the magnetic field lines and the magnetic induction vector in the air gap are presented. The target magnetic induction is 0.2 T, which is a typical requirement of the FFC NMR technique, which can be achieved with a magnetic core based on permanent magnets or coils. In addition, this application requires high magnetic induction uniformity. To achieve this goal, a solution including superconducting pieces is analyzed. Results are compared with a different FEM program.

Género e profissões: uma análise empírica para Portugal

Dissertação de Mestrado, Ciências Económicas e Empresariais, 9 de Janeiro de 2014, Universidade dos Açores.

Avaliação de fluoretos na água de consumo do concelho da Praia da Vitória (Ilha Terceira, Açores) e suas consequências a nível da saúde pública

Dissertação de Mestrado, Engenharia e Gestão de Sistemas de Água, 25 de Junho de 2014, Universidade dos Açores.

A influência da complexidade na eficiência operacional do consórcio modular

Pós-graduação em Engenharia de Produção - FEG

FMRI 3D registration based on Fourier space subsets using neural networks

In this work, we present a neural network (NN) based method designed for 3D rigid-body registration of FMRI time series, which relies on a limited number of Fourier coefficients of the images to be aligned. These coefficients, which are comprised in a small cubic neighborhood located at the first octant of a 3D Fourier space (including the DC component), are then fed into six NN during the learning stage. Each NN yields the estimates of a registration parameter. The proposed method was assessed for 3D rigid-body transformations, using DC neighborhoods of different sizes. The mean absolute registration errors are of approximately 0.030 mm in translations and 0.030 deg in rotations, for the typical motion amplitudes encountered in FMRI studies. The construction of the training set and the learning stage are fast requiring, respectively, 90 s and 1 to 12 s, depending on the number of input and hidden units of the NN. We believe that NN-based approaches to the problem of FMRI registration can be of great interest in the future. For instance, NN relying on limited K-space data (possibly in navigation echoes) can be a valid solution to the problem of prospective (in frame) FMRI registration.

Estudo e otimização de uma pilha de combustível de pequena potência (10W) e sua integração em equipamento portátil

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Éric Chevillard : des soucis esthétiques a l'engagement écologique

Artigo também disponível no PROA-UA: plataforma de revistas em open access da universidade de aveiro com o URI http://revistas.ua.pt/index.php/Carnets/article/view/768/695.