Probabilistic models for mechanical properties of prestressing strands

This study focus on the probabilistic modelling of mechanical properties of prestressing strands based on data collected from tensile tests carried out in Laboratório Nacional de Engenharia Civil (LNEC), Portugal, for certification purposes, and covers a period of about 9 years of production. The strands studied were produced by six manufacturers from four countries, namely Portugal, Spain, Italy and Thailand. Variability of the most important mechanical properties is examined and the results are compared with the recommendations of the Probabilistic Model Code, as well as the Eurocodes and earlier studies. The obtained results show a very low variability which, of course, benefits structural safety. Based on those results, probabilistic models for the most important mechanical properties of prestressing strands are proposed.

The intersection of people, technology and local space. PPGIS and Web in practice for participatory planning

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

Trajectory planning of redundant manipulators using genetic algorithms

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms are needed. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms. The results are compared with a genetic algorithm that adopts the direct kinematics. In both cases the trajectory planning is formulated as an optimization problem with constraints.

Manipulator trajectory planning using a MOEA

Generating manipulator trajectories considering multiple objectives and obstacle avoidance is a non-trivial optimization problem. In this paper a multi-objective genetic algorithm based technique is proposed to address this problem. Multiple criteria are optimized considering up to five simultaneous objectives. Simulation results are presented for robots with two and three degrees of freedom, considering two and five objectives optimization. A subsequent analysis of the spread and solutions distribution along the converged non-dominated Pareto front is carried out, in terms of the achieved diversity.

Planning the medical workforce - an analysis of the third repport of the Medical Workforce Standing Advisory Committee

Arquivos de Medicina 1998; 12(4): 246-248

Aplicação de métodos estocásticos na gestão de custos de construção de condutas de saneamento

O trabalho apresentado centra-se na determinação dos custos de construção de condutas de pequenos e médios diâmetros em Polietileno de Alta Densidade (PEAD) para saneamento básico, tendo como base a metodologia descrita no livro Custos de Construção e Exploração – Volume 9 da série Gestão de Sistemas de Saneamento Básico, de Lencastre et al. (1994). Esta metodologia descrita no livro já referenciado, nos procedimentos de gestão de obra, e para tal foram estimados custos unitários de diversos conjuntos de trabalhos. Conforme Lencastre et al (1994), “esses conjuntos são referentes a movimentos de terras, tubagens, acessórios e respetivos órgãos de manobra, pavimentações e estaleiro, estando englobado na parte do estaleiro trabalhos acessórios correspondentes à obra.” Os custos foram obtidos analisando vários orçamentos de obras de saneamento, resultantes de concursos públicos de empreitadas recentemente realizados. Com vista a tornar a utilização desta metodologia numa ferramenta eficaz, foram organizadas folhas de cálculo que possibilitam obter estimativas realistas dos custos de execução de determinada obra em fases anteriores ao desenvolvimento do projeto, designadamente numa fase de preparação do plano diretor de um sistema ou numa fase de elaboração de estudos de viabilidade económico-financeiros, isto é, mesmo antes de existir qualquer pré-dimensionamento dos elementos do sistema. Outra técnica implementada para avaliar os dados de entrada foi a “Análise Robusta de Dados”, Pestana (1992). Esta metodologia permitiu analisar os dados mais detalhadamente antes de se formularem hipóteses para desenvolverem a análise de risco. A ideia principal é o exame bastante flexível dos dados, frequentemente antes mesmo de os comparar a um modelo probabilístico. Assim, e para um largo conjunto de dados, esta técnica possibilitou analisar a disparidade dos valores encontrados para os diversos trabalhos referenciados anteriormente. Com os dados recolhidos, e após o seu tratamento, passou-se à aplicação de uma metodologia de Análise de Risco, através da Simulação de Monte Carlo. Esta análise de risco é feita com recurso a uma ferramenta informática da Palisade, o @Risk, disponível no Departamento de Engenharia Civil. Esta técnica de análise quantitativa de risco permite traduzir a incerteza dos dados de entrada, representada através de distribuições probabilísticas que o software disponibiliza. Assim, para por em prática esta metodologia, recorreu-se às folhas de cálculo que foram realizadas seguindo a abordagem proposta em Lencastre et al (1994). A elaboração e a análise dessas estimativas poderão conduzir à tomada de decisões sobre a viabilidade da ou das obras a realizar, nomeadamente no que diz respeito aos aspetos económicos, permitindo uma análise de decisão fundamentada quanto à realização dos investimentos.

Conceção, seleção e implementação de um sistema de informação: ERP - enterprise resource planning

As organizações são entidades de natureza sistémica, composta, na sua maioria por várias pessoas que interagindo entre si, se propõem atingir objetivos comuns. Têm, frequentemente, de responder a alterações da envolvente externa através de processos de mudança organizacional, sendo fundamentalmente adaptativas, pois, para sobreviver, precisam de se reajustar continuamente às condições mutáveis do meio. O sucesso das organizações depende da sua capacidade de interação com o meio envolvente, ou seja, da sua capacidade de inovar e operar local ou globalmente, criando novas oportunidades de negócio que importa aproveitar. As tecnologias e os sistemas de informação e a forma como são utilizadas são fatores determinantes nesses processos de evolução e mudança. É necessário que a estratégia de TI esteja alinhada com os objetivos de negócio e que a sua utilização contribua para aumentos de produtividade e de eficiência no seu desempenho. Este trabalho descreve a análise, conceção, seleção e implementação de um Sistema de Informação na Portgás, S.A. baseado de um ERP - Enterprise Resource Planning, capaz de suportar a mudança organizacional e melhorar o desempenho global da organização. Promovendo numa primeira fase um crescimento exponencial do negócio e, de seguida, a adaptação da organização ao mercado concorrencial. O caso descreve o trabalho realizado pelo candidato e por equipas internas e externas, de levantamentos de requisitos gerais, técnicos e funcionais, desenvolvimento de um caderno de encargos, seleção, implementação e exploração de um ERP SAP. A apresentação e discussão do caso são enquadradas numa revisão de literatura sobre o papel das TI nos processos de mudança organizativa, alinhamento estratégico e vantagem competitiva das TI, contributo das TI para o aumento da produtividade, processos adoção e difusão das TI, fatores críticos de sucesso e BPM –Business Process Management

Probabilistic tsunami hazard in the Northeast Atlantic from near- and far-field tectonic sources

In this article, we present the first study on probabilistic tsunami hazard assessment for the Northeast (NE) Atlantic region related to earthquake sources. The methodology combines the probabilistic seismic hazard assessment, tsunami numerical modeling, and statistical approaches. We consider three main tsunamigenic areas, namely the Southwest Iberian Margin, the Gloria, and the Caribbean. For each tsunamigenic zone, we derive the annual recurrence rate for each magnitude range, from Mw 8.0 up to Mw 9.0, with a regular interval, using the Bayesian method, which incorporates seismic information from historical and instrumental catalogs. A numerical code, solving the shallow water equations, is employed to simulate the tsunami propagation and compute near shore wave heights. The probability of exceeding a specific tsunami hazard level during a given time period is calculated using the Poisson distribution. The results are presented in terms of the probability of exceedance of a given tsunami amplitude for 100- and 500-year return periods. The hazard level varies along the NE Atlantic coast, being maximum along the northern segment of the Morocco Atlantic coast, the southern Portuguese coast, and the Spanish coast of the Gulf of Cadiz. We find that the probability that a maximum wave height exceeds 1 m somewhere in the NE Atlantic region reaches 60 and 100 % for 100- and 500-year return periods, respectively. These probability values decrease, respectively, to about 15 and 50 % when considering the exceedance threshold of 5 m for the same return periods of 100 and 500 years.

Probabilistic consensus clustering using evidence accumulation

Clustering ensemble methods produce a consensus partition of a set of data points by combining the results of a collection of base clustering algorithms. In the evidence accumulation clustering (EAC) paradigm, the clustering ensemble is transformed into a pairwise co-association matrix, thus avoiding the label correspondence problem, which is intrinsic to other clustering ensemble schemes. In this paper, we propose a consensus clustering approach based on the EAC paradigm, which is not limited to crisp partitions and fully exploits the nature of the co-association matrix. Our solution determines probabilistic assignments of data points to clusters by minimizing a Bregman divergence between the observed co-association frequencies and the corresponding co-occurrence probabilities expressed as functions of the unknown assignments. We additionally propose an optimization algorithm to find a solution under any double-convex Bregman divergence. Experiments on both synthetic and real benchmark data show the effectiveness of the proposed approach.

Strategic Planning and Organizational Effectiveness in Social Service Organizations in Portugal

This study aims to understand the reality of social service organizations, the level of implementation of the strategic planning as well as the impact of its application on organizational effectiveness. At first, we will group organizations in clusters according to the level of strategic planning implementation and its degree of effectiveness. Secondly, we will analyse all the different groups. Given the growing number of social service organizations and the consequent complexity of their structures, it turns out the need for these organizations adopt formal management techniques. Strategic planning is a valuable strategic management tool and one of its main objectives is to make organizations more effective. Therefore, the research has been conducted in order to determine if strategic planning is implemented in social service organizations and which effects has its application on organizational effectiveness. The survey, applied to 220 social service organizations, allowed us to gather them into different clusters, showing that different levels of strategic planning determine distinct degrees of organizational efficiency. Finally, it should be noted that findings of this research may be essential to decision makers of these organizations, because it was shown that the adoption of strategic planning has a positive influence on organizational effectiveness of social service organizations.

Planning smart cities using wireless low energy monitoring systems

Thesis to obtain the Master Degree in Electronics and Telecommunications Engineering

Impact of Distributed Generation in the Transmission System Expansion Planning

In this work, the impact of distributed generation in the transmission expansion planning will be simulated through the performance of an optimization process for three different scenarios: the first without distributed generation, the second with distributed generation equivalent to 1% of the load, and the third with 5% of distributed generation. For modeling the expanding problem the load flow linearized method using genetic algorithms for optimization has been chosen. The test circuit used is a simplification of the south eastern Brazilian electricity system with 46 buses.

Lean enterprise resource planning

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia e Gestão Industrial

Probabilistic maintenance and optimization strategies for deteriorating civil infrastructures

In developed countries, civil infrastructures are one of the most significant investments of governments, corporations, and individuals. Among these, transportation infrastructures, including highways, bridges, airports, and ports, are of huge importance, both economical and social. Most developed countries have built a fairly complete network of highways to fit their needs. As a result, the required investment in building new highways has diminished during the last decade, and should be further reduced in the following years. On the other hand, significant structural deteriorations have been detected in transportation networks, and a huge investment is necessary to keep these infrastructures safe and serviceable. Due to the significant importance of bridges in the serviceability of highway networks, maintenance of these structures plays a major role. In this paper, recent progress in probabilistic maintenance and optimization strategies for deteriorating civil infrastructures with emphasis on bridges is summarized. A novel model including interaction between structural safety analysis,through the safety index, and visual inspections and non destructive tests, through the condition index, is presented. Single objective optimization techniques leading to maintenance strategies associated with minimum expected cumulative cost and acceptable levels of condition and safety are presented. Furthermore, multi-objective optimization is used to simultaneously consider several performance indicators such as safety, condition, and cumulative cost. Realistic examples of the application of some of these techniques and strategies are also presented.

25 anos de Inquérito Nacional de Saúde em Portug

RESUMO - O Inquérito Nacional de Saúde é um instrumento de observação em saúde promovido pelo Ministério da Saúde desde 1987, em resposta às necessidades crescentes de informação de saúde ligadas ao estabelecimento e às exigências de planeamento e avaliação decorrentes da instituição do Serviço Nacional de Saúde. O Inquérito Nacional de Saúde conta, até agora, com quatro edições. Os dados provêm através do estudo transversal de amostras probabilísticas da população portuguesa, através de entrevistas no domicílio, utilizando instrumentos e métodos válidos e estáveis. Os indicadores gerados descrevem o estado de saúde, utilização de cuidados de saúde e determinantes de saúde da população portuguesa residente em unidades de alojamento familiar e tem representatividade a nível nacional e regional. Além de útil para a investigação dos padrões e tendências na área da saúde da população, esta informação é importante como elemento de planeamento, na identificação de necessidades em saúde e na avaliação dos eventuais efeitos e impactes das intervenções realizadas na saúde da população. A evolução do Inquérito Nacional de Saúde depende da definição das necessidades de informação epidemiológica por parte do Estado e da sua integração no sistema europeu de inquéritos de saúde. --------------------------ABSTRACT – The National Health Interview Survey is an instrument of observation in health promoted by the Ministry of Health since 1987, in response to the growing demand for health information, derived from the institution of the National Health Service, as well as its planning and evaluation activities. The National Health Interview Survey has had four editions so far. Data are obtained through the cross-sectional study of probabilistic samples of the Portuguese population, through interviews at home, using valid and stable instruments and methods. Obtained indicators describe the state of health, use of health care and health determinants of the Portuguese population living in familiar dwellings, and are representative at national and regional levels. Besides its usefulness for the study of patterns and trends, this information is important for planning purposes, in the identification of health needs and for the evaluation of the eventual effects of the planned health interventions. The future of the National Health Interview Survey depends on the State’s definition of the needs of epidemiological information and also on its participation in the European system of health surveys. Keywords: health surveys; health indicators; epidem