Invited review: Models for the optimization of regional wastewater treatment systems

European Journal of Operational Research, nº 73 (1994)

Estimation of infection rate in epidemic models with multiple populations

Dissertação para obtenção do Grau de Mestre em Matemática e Aplicações Especialização em Actuariado, Estatística e Investigação Operacional

Hybrid systems biology: application to Escherichia coli

Dissertation presented to obtain a Master degree in Biotechnology

Critical Velocity obtained using Simplified Models of the Railway Track: Viability and Applicability

Increased demands on the capacity of the railway network gave rise to new issues related to the dynamic response of railway tracks subjected to moving vehicles. Thus, it becomes important to evaluate the applicability of traditionally used simplified models which have a closed form solution. Regarding simplified models, transversal vibrations of a beam on a visco-elastic foundation subjected to a moving load are considered. Governing equations are obtained by Hamilton’s principle. Shear distortion, rotary inertia and effect of axial force are accounted for. The load is introduced as a time varying force moving at a constant velocity. Transversal vibrations induced by the load are solved by the normal-mode analysis. Reflected waves at the extremities of the full beam are avoided by introduction of semi-infinite elements. Firstly, the critical velocity obtained from this model is compared with results of an undamped Euler- Bernoulli formulation with zero axial force. Secondly, a finite element model in ABAQUS is examined. The new contribution lies in the introduction of semi- infinite elements and in the first step to a systematic comparison, which have not been published so fa

Estimation Models for the adoption and use of information technology: internet-related technologies at firm level in the Portuguese and European context

Dissertação apresentada como requisito parcial para obtenção do grau de Doutor em Gestão de Informação

Behavioral and synaptic circuit analysis in models of neuropsychiatric disorders: Dissecting the in vivo role of the postsynaptic density proteins nArgBP2 and Shank3 using genetic engineered mice

Dissertation presented to obtain the Ph.D degree in Biology

Órgão de governação de topo do hospital público português : estrutura e constituição

RESUMO - Pretende-se com este projecto fazer uma reflexão sobre a problemática dos modelos de governação na gestão pública de hospitais e sobre a forma de incrementar a capacidade estratégica da gestão, contextualizando a governação dos hospitais num quadro mais amplo e comunitário, integrando os interesses e expectativas dos diversos interessados no funcionamento dos hospitais públicos. Sinteticamente, a questão fundamental de investigação é: Como conseguirá o sistema de governação de um hospital público incorporar os interesses de todos os seus stakeholders e shareholders? A resposta a esta questão integra duas fases, uma primeira dedicada ao estudo de um novo modelo de configuração para o órgão de governação de topo do hospital público e uma segunda fase dedicada à construção de um questionário para discussão e validação do modelo proposto através da técnica Delphi. A metodologia utilizada passou pela condução prévia de entrevistas exploratórias a informadores privilegiados e pela divisão do projecto em duas partes – uma primeira parte de enquadramento que segue a metodologia clássica da revisão bibliográfica e uma segunda parte prática que segue a metodologia Delphi, precedida de um levantamento das questões críticas para integrar no questionário que servirá de base à discussão dos peritos. Como resultado, o actual modelo pareceu-nos dificultar a consideração das expectativas e dos interesses dos proprietários/accionistas e dos stakeholders em geral do hospital público, concluindo-se pela necessidade de um novo modelo que estabeleça, inequivocamente, os papéis e as funções inerentes ao órgão de governação, garantindo a internalização da perspectiva de todos os interessados. -------------------------------ABSTRACT - The objective of this project is to reflect on the problematic of models of governance in the public management of hospitals and on the means for incrementing strategic management capacity. It does so by contextualizing the governance of public hospitals on a more ample community–wide scale, integrating the interests and expectations of different parties. The main research question is: how can the system of governance of a public hospital incorporate the interests of all its stakeholders and shareholders? The answer to this question involves two phases, one dedicated to the study of the configuration of the top-level governing body of the public hospital and, a second, dedicated to the construction of a questionnaire for discussion and validation of the proposed model by means of a Delphi technique. The methodology involved, first of all, exploratory interviews with key- informants and by the structuring of the project in two parts – the first, dedicated to contextualization by means of a standard literature review and the second, essentially practical by means of the Delphi technique, preceded by the raising of critical questions that integrate the questionnaire that will form the basis of expert discussion. The present model of public hospital governance appears to limit the possibility of integrating the expectations and interests of stakeholders and owner/shareholders. It is concluded that a new model is needed, one that establishes unequivocally the roles and functions of the top- level governing body, thereby

Models for pheromone evaluation in Ant Systems for Mobile Ad-hoc networks

On a mobile ad-hoc network environment, where the resources are scarce, the knowledge about the network's link state is essential to optimize the routing procedures. This paper presents a study about different pheromone evaluation models and how they react to possible changes in traffic rate. Observing how the pheromone value on a link changes, it could be possible to identify certain patterns which can indicate the path status. For this study, the behavior of the Ant System evaluation model was compared with a Temporal Active Pheromone model (a biological approach) and a Progressive Pheromone Reduction model with and without a maximum pheromone limit.

Mathematical modelling of shallow flows: closure models drawn from grain-scale mechanics of sediment transport and flow hydrodynamics

Canadian Journal of Civil Engineering 36(10) 1605–16

Development and validation of a risk model for prediction of hazardous alcohol consumption in general practice attendees : the PredictAL study

Background: Little is known about the risk of progression to hazardous alcohol use in people currently drinking at safe limits. We aimed to develop a prediction model (predictAL) for the development of hazardous drinking in safe drinkers. Methods: A prospective cohort study of adult general practice attendees in six European countries and Chile followed up over 6 months. We recruited 10,045 attendees between April 2003 to February 2005. 6193 European and 2462 Chilean attendees recorded AUDIT scores below 8 in men and 5 in women at recruitment and were used in modelling risk. 38 risk factors were measured to construct a risk model for the development of hazardous drinking using stepwise logistic regression. The model was corrected for over fitting and tested in an external population. The main outcome was hazardous drinking defined by an AUDIT score >= 8 in men and >= 5 in women. Results: 69.0% of attendees were recruited, of whom 89.5% participated again after six months. The risk factors in the final predictAL model were sex, age, country, baseline AUDIT score, panic syndrome and lifetime alcohol problem. The predictAL model's average c-index across all six European countries was 0.839 (95% CI 0.805, 0.873). The Hedge's g effect size for the difference in log odds of predicted probability between safe drinkers in Europe who subsequently developed hazardous alcohol use and those who did not was 1.38 (95% CI 1.25, 1.51). External validation of the algorithm in Chilean safe drinkers resulted in a c-index of 0.781 (95% CI 0.717, 0.846) and Hedge's g of 0.68 (95% CI 0.57, 0.78). Conclusions: The predictAL risk model for development of hazardous consumption in safe drinkers compares favourably with risk algorithms for disorders in other medical settings and can be a useful first step in prevention of alcohol misuse.

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 mechanicalproperties is examined and the results are compared with the recommendations of the ProbabilisticModel 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 modelsfor the most important mechanical properties of prestressing strands are proposed.

Non-linear time series models

The last three decades have seen quite dramatic changes the way we modeled time dependent data. Linear processes have been in the center stage in modeling time series. As far as the second order properties are concerned, the theory and the methodology are very adequate.However, there are more and more evidences that linear models are not sufficiently flexible and rich enough for modeling purposes and that failure to account for non-linearities can be very misleading and have undesired consequences.

A score test for non-nested hypotheses with applications to discrete data models

This paper suggests that a convenient score test against non-nested alternatives can be constructed from the linear combination of the likelihood functions of the competing models. It is shown that this procedure is essentially a test for the correct specification of the conditional distribution of the variable of interest.

Tuple-based morphisms for interoperability establishment of financial information models

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

Landslide susceptibility assessment in Karanganyar regency - Indonesia - Comparison of knowledge-based and Data-driven Models

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