A public transport bus assignment problem: parallel metaheuristics assessment

Combinatorial Optimization Problems occur in a wide variety of contexts and generally are NP-hard problems. At a corporate level solving this problems is of great importance since they contribute to the optimization of operational costs. In this thesis we propose to solve the Public Transport Bus Assignment problem considering an heterogeneous fleet and line exchanges, a variant of the Multi-Depot Vehicle Scheduling Problem in which additional constraints are enforced to model a real life scenario. The number of constraints involved and the large number of variables makes impracticable solving to optimality using complete search techniques. Therefore, we explore metaheuristics, that sacrifice optimality to produce solutions in feasible time. More concretely, we focus on the development of algorithms based on a sophisticated metaheuristic, Ant-Colony Optimization (ACO), which is based on a stochastic learning mechanism. For complex problems with a considerable number of constraints, sophisticated metaheuristics may fail to produce quality solutions in a reasonable amount of time. Thus, we developed parallel shared-memory (SM) synchronous ACO algorithms, however, synchronism originates the straggler problem. Therefore, we proposed three SM asynchronous algorithms that break the original algorithm semantics and differ on the degree of concurrency allowed while manipulating the learned information. Our results show that our sequential ACO algorithms produced better solutions than a Restarts metaheuristic, the ACO algorithms were able to learn and better solutions were achieved by increasing the amount of cooperation (number of search agents). Regarding parallel algorithms, our asynchronous ACO algorithms outperformed synchronous ones in terms of speedup and solution quality, achieving speedups of 17.6x. The cooperation scheme imposed by asynchronism also achieved a better learning rate than the original one.

Digital interconnectivity as a driver for port and logistics competitiveness

Creating an innovative tool that takes advantage of digital interconnectivity between shipping agencies and husbandry services suppliers was the starting point. But the main purpose of this paper is to figure out if that represents a business opportunity. It describes the preliminary stages undertaken, as the connections with the main potential providers of the husbandry services. This was carried out as a qualitative research, based on interviews given by shipping agencies that contributed as a source of data about their activities but also to survey their acceptance of the concept that could change the way of doing business in this area.At the same time, inquiries have been made to build financial scenarios that show the costs and revenue streams allocated to this project. Considering the data collected from the main players in husbandry services and the different outcomes, the feasibility of this project is assessed. Even though the paradigm was well received by all the firms contacted, the development costs turn out to be the main threat to the project so further steps are advised.

Towards a GIS-T database design and implementation for public transit planning: the case study of Dar-Es-salaam metropolitan city, Tanzania.

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

Customisable e-training programmes based on trainees profiles

Dissertation presented at Faculdade de Ciências e Tecnologia of Universidade Nova de Lisboa to obtain the Master degree in Electrical and Computer Engineering

From the Lisbon strategy to EU2020: illusion or progress for european economies?

To be published at Krings, Bettina-J. ed. (2011), Brain Drain or Brain Gain? Changes of Work in Knowledge-based Societies, Berlin, Ed. Sigma. The author wants to thanks the comments and suggestions from Bettina Krings and Sylke Wintzer. They are not, however, responsible for the final result.

Utilização do processador Cell para o processamento de dados obtidos por tomografia aplicada a materiais compósitos

Dissertação de Mestrado em Engenharia Informática

The significance of Traveler's Route Knowledge for Choice of commuting mode of transport

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

Information Systems Outsourcing Adoption

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

Clustering medical tourism in Algarve: setting the first steps for the the health authority

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Program Catapultas: Education for development in Bairro Padre Cruz

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

External brand extensions impact on Diesel's brand image

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Sistema de iluminação eficiente utilizando a tecnologia LED para espaços públicos interiores

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

The optimization of the complaints management system

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Clearing the cloudy crystal balls: Hybrid modelling for energy and climate change mitigation scenarios – A case study for Portugal

Dissertação para obtenção do Grau de Doutor em Ambiente

Desenvolvimento e aplicação do algoritmo enxame de partículas na determinação da máxima injeção nodal em redes de energia elétrica

O objetivo desta dissertação é a determinação da máxima injeção nodal numa rede de energia elétrica, ou seja, qual o valor total máximo de potência ativa que é possível injetar e qual a sua distribuição pelos diversos nós da rede simultaneamente. Determinámos esta máxima injeção nodal em duas situações distintas: injeção não simultânea, injetando potência em um só nó de cada vez e injeção simultânea, injetando potência em todos os nós da rede simultaneamente. Sendo este um problema de natureza combinatória, utilizámos para esta determinação o algoritmo conhecido como nuvem ou enxame de partículas, adaptando-o ao nosso problema. Desenvolvemos o software na linguagem de programação Python utilizando o ambiente Eclipse. Para resolver o trânsito de energia utilizámos o programa PSSE University.Para os exemplos de aplicação utilizámos duas redes de energia elétrica, uma de 6 e outra de 14 barramentos. Estas redes foram baseadas nas redes IEEE 6 BUS e IEEE 14 BUS respetivamente. Concluímos que o algoritmo nuvem ou enxame de partículas cumpriu o objetivo traçado, obtendo as melhores soluções para cada um dos casos, máxima injeção nodal não simultânea e máxima injeção nodal simultânea. No contexto deste problema, o parâmetro chave do algoritmo, comprovado pelos ensaios feitos, é a velocidade máxima de deslocação das partículas, tomando valores típicos de 7 a 10 para a rede de 6 barramentos e de 20 a 25 para a de 14 barramentos.