Ergodicity of polygonal slap maps

Polygonal slap maps are piecewise affine expanding maps of the interval obtained by projecting the sides of a polygon along their normals onto the perimeter of the polygon. These maps arise in the study of polygonal billiards with non-specular reflections laws. We study the absolutely continuous invariant probabilities of the slap maps for several polygons, including regular polygons and triangles. We also present a general method for constructing polygons with slap maps having more than one ergodic absolutely continuous invariant probability.Comment: 17 pages, 6 figure

Hyperbolic polygonal billiards with finitely many ergodic SRB measures

We study polygonal billiards with reflection laws contracting the reflected angle towards the normal. It is shown that if a polygon does not have parallel sides facing each other, then the corresponding billiard map has finitely many ergodic SRB measures whose basins cover a set of full Lebesgue measure.Comment: 26 pages, 2 figure

Design and implementation of an autonomous, proactive, and reactive software infrastructure to help improving the management level of projects

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de ComputadoresOver the years, collaboration between humans and organizations have been increasing and becoming vital to face new challenges and achieve the greatest common goals. The development of new technologies and internet capabilities promoted the emergence of new collaboration types, i.e., collaboration using software connected through internet (Collaborative Workspaces software). The use of the internet amplifies the range of action and the speed of communication among the actors involved in a collaboration. The collaboration amongst organizations is project-oriented (the common goal is to deal with projects) where several actors involved in the collaboration share their knowledge with each other. These actors are, indeed, the knowledge holders and the system which supports the collaboration has to collect and assess the knowledge from them. For this reason, this thesis aims to design and implement a software infrastructure to capture and capitalize the knowledge created over several projects. Such software is human-centered and has an autonomous, proactive and reactive behaviour to handle all users‟ needs. This software promotes its own continuous learning by analysing humans‟ behaviour over several projects, extracting information from that behaviour, and having Context-awareness. Additionally, it relies on Data mining technologies and semantic services, in order to provide a continuous monitoring of the whole project during its life cycle. The software developed is called “Companion” and has been assessed as a part of the CoSpaces Integrated Project

Leader´s attitudes towards corruption - empirical evidence from Northern Mozambique

We pretend to derive the effect of natural resources on leader’s attitudes and behaviors in deteriorated African economies. Through self-reported data from Northern Mozambique on leaders and households, we examine the effects on attitudes of corruption, appropriation of resources, trust and violence from the leader. We find that a resource discovery has a positive influence on leader’s proneness to corruption – paying bribes and ignoring the law –, especially, for the ones found during the leader’s tenure. The existence of resources also affects positively the leader’s idea of appropriation of rents, the trust in the community and the generosity in providing something to its community

Implementation of an information system for resource and process management in an industrial facility

The increasing investment in information systems for industrial production control, combined with the advent of the fourth industrial revolution, allows to improve decision making, providing a more efficient manufacturing process. However, for small and medium-sized enterprises in this sector, the complexity of existing solutions and the need to perform, in a preliminary phase, a substantial investment makes it difficult to implement these types of systems, accentuating, in terms of competitiveness, the gap between small and large companies. The proposed system, developed within the scope of this dissertation, aims to assist this types of companies, more specifically, a local business entity in the branch of the aeronautical industry, since it allows to optimize the monitoring of industrial resources and processes at the shop floor level. To support the design and implementation of the solution, an analysis on the operation of industrial facilities and techniques adopted in the field of industrial information systems is carried out. The entire development phase encompasses software engineering processes and culminates with the delivery of a prototype of a Spring web application, deployed on the partner entity’s server and positively evaluated in the execution of development and functional tests; Sumário: Implementação de sistema de informação para gestão de recursos e processos industriais O investimento crescente em sistemas de informação para controlo de produção industrial, aliado ao advento de uma quarta revolução industrial, permite aprimorar a tomada de decisões, proporcionando um processo de manufatura mais eficiente. No entanto, para pequenas e médias empresas deste sector, a complexidade das soluções existentes e a necessidade de efetuar um investimento preliminar substancial dificulta a implementação deste tipo de sistemas, acentuando, a discrepância competitiva entre pequenas e grandes empresas. O sistema proposto, desenvolvido no âmbito do trabalho da presente dissertação, visa auxiliar esta tipologia de empresas, mais concretamente, uma entidade empresarial local no ramo da indústria aeronáutica, na medida em que permite otimizar a monitorização de recursos e processos industriais ao nível do chão de fábrica. Para suporte da conceção e implementação da solução realiza-se uma análise do funcionamento de instalações industriais e de técnicas adotadas no domínio de sistemas de informação para aplicação industrial. A totalidade da fase de desenvolvimento engloba processos de engenharia de software e culmina com a entrega de um protótipo de uma aplicação web Spring, implantada no servidor da entidade parceira e, positivamente avaliada na execução de testes de desenvolvimento e funcionais

PhagePro: prophage finding tool

Dissertação de mestrado em BioinformáticaBacteriophages are viruses that infect bacteria and use them to reproduce. Their reproductive cycle can be lytic or lysogenic. The lytic cycle leads to the bacteria death, given that the bacteriophage hijacks hosts machinery to produce phage parts necessary to assemble a new complete bacteriophage, until cell wall lyse occurs. On the other hand, the lysogenic reproductive cycle comprises the bacteriophage genetic material in the bacterial genome, becoming a prophage. Sometimes, due to external stimuli, these prophages can be induced to perform a lytic cycle. Moreover, the lysogenic cycle can lead to significant modifications in bacteria, for example, antibiotic resistance. To that end, PhagePro was created. This tool finds and characterises prophages inserted in the bacterial genome. Using 42 features, three datasets were created and five machine learning algorithms were tested. All models were evaluated in two phases, during testing and with real bacterial cases. During testing, all three datasets reached the 98 % F1 score mark in their best result. In the second phase, the results of the models were used to predict real bacterial cases and the results compared to the results of two tools, Prophage Hunter and PHASTER. The best model found 110 zones out of 154 and the model with the best result in dataset 3 had 94 in common. As a final test, Agrobacterium fabrum strC68 was extensively analysed. The results show that PhagePro was capable of detecting more regions with proteins associated with phages than the other two tools. In the ligth of the results obtained, PhagePro has shown great potential in the discovery and characterisation of bacterial alterations caused by prophages.Bacteriófagos são vírus que infetam bactérias usando-as para garantir a manutenção do seu genoma. Este processo pode ser realizado por ciclo lítico ou lipogénico. O ciclo lítico consiste em usar a célula para seu proveito, criar bacteriófagos e lisar a célula. Por outro lado, no ciclo lipogénico o bacteriófago insere o seu código genético no genoma da bactéria, o que pode levar à transferência de genes de interesse, tornando-se importante uma monitorização dos profagos. Assim foi desenvolvido o PhagePro, uma ferramenta capaz de encontrar e caracterizar bacteriófagos em genomas bactérias. Foram criadas features para distinguir profagos de bactérias, criando três datasets e usando algoritmos de aprendizagem de máquina. Os modelos foram avaliados durante duas fases, a fase de teste e a fase de casos reais. Na primeira fase de testes, o melhor modelo do dataset 1 teve 98% de F1 score, dataset 2 teve 98% e do dataset 3 também teve 98%. Todos os modelos, para teste em casos reais, foram comparados com previsões de duas ferramentas Prophage Hunter e PHASTER. O modelo com os melhores resultados obteve 110 de 154 zonas em comum com as duas ferramentas e o modelo do dataset 3 teve 94 zonas. Por fim, foi feita a análise dos resultados da bactéria Agrobacterium fabrum strC68. Os resultados obtidos mostram resultados diferentes, mas válidos, as ferramentas comparadas, visto que o PhagePro consegue detectar zonas com proteínas associadas a fagos que as outras tools não conseguem. Em virtude dos resultados obtidos, PhagePro mostrou que é capaz de encontrar e caracterizar profagos em bactérias.Este estudo contou com o apoio da Fundação para a Ciência e Tecnologia (FCT) portuguesa no âmbito do financiamento estratégico da unidade UIDB/04469/2020. A obra também foi parcialmente financiada pelo Projeto PTDC/SAU-PUB/29182/2017 [POCI-01-0145-FEDER-029182]