Covariant action for bouncing cosmologies in modified Gauss-Bonnet gravity

Cyclic universes with bouncing solutions are candidates for solving the big bang initial singularity problem. Here we seek bouncing solutions in a modified Gauss-Bonnet gravity theory, of the type $R+f(G)$, where $R$ is the Ricci scalar, $G$ is the Gauss-Bonnet term, and $f$ some function of it. In finding such a bouncing solution we resort to a technique that reduces the order of the differential equations of the $R+f(G)$ theory to second order equations. As general relativity is a theory whose equations are of second order, this order reduction technique enables one to find solutions which are perturbatively close to general relativity. We also build the covariant action of the order reduced theory.Comment: 8 page

Fault Tolerant Reconfigurable Control of a Water Delivery Canal - Actuators Faults

This work addresses the problem of designing fault tolerant controllers for a water delivery canal that tackle actuators faults. The type of faults considered consists of blocking of one of the gates. The detection of the fault is made by comparing the gate position command with the actual (measured) gate position. Both centralized and distributed controllers are made for local upstream water level control. Centralized controllers are multivariable LQG-LTR controllers that use a model of the system with all the available manipulated inputs (gate positions) and all the available outputs (pool levels). Initially, three gates and three pools are controlled. After the fault detection, the controller is reconfigured to use the only two still operating gates and the corresponding two pool water levels. Distributed control uses local (SISO) LQG-LTR controllers that negotiate with their neighbors in order to be coordinated. When a fault occurs, this negotiation takes place only among the controllers connected to the actuators that are not in a fault state. Experimental results obtained in a pilot canal are presented

Business in practice: performance analysis of Ixor automotive company and my personal reflection on a simulated business

Business in Practice (BiP) is a 6-year immersive simulation in managing an automotive manufacturer, focusing on the real-world complexities involved in both running a business and managing interpersonal relations. This dissertation, enriched by personal reflections, critically explores Strategy, Innovation, and Finance functions within the firm. It elucidates the essential interplay between business units while considering sustainability as a pivotal cross-functional theme. Through analyzing two critical incidents, the dissertation serves as a model for my personal growth and self-understanding. These findings resonate with both practical management and academic research, underscoring the essential role of effective communication for organizational success

Design evaluation on the production of sloping walls without support structures in additive manufacturing

Technologies have been advancing significantly over the years. Additive manufacturing is a technology that is in constant growth in the matter of applications, materials, processes and machines. In spite of its advanced technology, in most cases the produced models need to build with support structures which slows down production. Hence it is necessary to understand this type of limitation. Additive manufacturing has the ability of producing geometrical parts from a CAD model, creating rapidly physical models by joining materials, layer by layer, to represent models or even to test its functionality. It is capable of printing geometrical complex parts with an extended design freedom, but in some systems, needs to build support structures to support the part during production. The FDM technology is one of the additive manufacturing processes that produces the model by connecting polymeric materials one layer at a time. The machine software reads and manipulates the STL file to define all the proper conditions to print the required model, as well as defining the need to build support structures. It is relevant to establish design guidelines to achieve an improved result. Therefore, the focus of this thesis is to evaluate the need of support structures in a set of defined models with designated geometric characteristics. The work consisted in producing models with sloping walls using the FDM process in different machines in order to understand the different behaviours of the shapes and to conclude at which point it is possible to produce a geometric feature without support structures while maintaining geometric accuracy

Conectividade definida por software em ambientes móveis

Broadband Internet access on trains has become an expected service for passengers, and the rise in quality demand has been posing a challenge to service providers. There are solutions for Internet access on trains that lack the flexibility and redundancy needed for an improved QoS in the network. Thus, this dissertation studies two new load balancing solutions, one distributed and the other centralized. In an emulated train network, routers of each car communicate their network statistics to other nodes of the network, to be used in load balancing decisions. In the distributed solution, each router has the capacity to make load balancing decisions, while in the centralized solution, an onboard controller makes those decisions. The latter solution is based on load balancing in an SDN environment. In this system, a remote entity aggregates the passengers’ traffic and forwards it to an external network, or to the Internet. The systems must provide an improved quality of experience to the passengers on the train and the total avaliable bandwidth should be distributed evenly by all cars. Requirements were established for the systems, which were developed after an in-depth analysis of solutions for Internet access on board found in the literature. After obtaining the results of the performance tests, it was concluded that the systems improve the QoE of the passengers, as long as the network conditions are approximately constant for an extended period.O acesso à Internet de banda larga em comboios tornou-se num serviço esperado por parte dos passageiros e o aumento na exigência de qualidade tem constituído um desafio para os prestadores de serviços. Existem soluções de acesso à Internet em comboios que carecem da flexibilidade e redundância necessárias para uma melhor qualidade de serviço na rede. Assim, esta dissertação estuda duas novas soluções de balanceamento de carga, uma distribuída e outra centralizada. Numa rede de comboio emulada, routers de cada carruagem comunicam as suas estatísticas de rede para outros nós da rede, para posteriormente serem tomadas decisões de balanceamento de carga. Na solução distribuída, cada router tem capacidade de tomar decisões de balanceamento de carga, enquanto que na solução centralizada, um controlador dentro do comboio toma essas decisões. Esta última solução baseiase num balanceamento de carga em ambiente SDN. Neste sistema, uma entidade remota agrega o tráfego dos passageiros e encaminha-o para uma rede externa, ou para a Internet. Os sistemas devem proporcionar uma qualidade de experiência melhorada aos passageiros do comboio e a largura de banda total disponível deve ser distribuída mais uniformememente por todas as carruagens. Requisitos foram estabelecidos para os sistemas, que foram desenvolvidos após uma análise aprofundada das soluções de acesso à Internet em comboios encontradas na literatura. Após a obtenção dos resultados dos testes de desempenho, concluiu-se que as duas soluções melhoram o QoE dos passageiros, desde que as condições da rede sejam aproximadamente constantes durante um certo período.Mestrado em Engenharia de Computadores e Telemátic

Estrutura das âncoras de carreira : estudo exploratório com uma amostra de engenheiros portugueses

Tese de mestrado, Psicologia (Psicologia dos Recursos Humanos, do Trabalho e das Organizações), Universidade de Lisboa, Faculdade de Psicologia, 2011Contrariamente à tipologia preconizada por Edgar Schein, que apenas admite a dominância de uma âncora de carreira, o presente estudo incide na actual linha de investigação que propõe uma reconceptualização da teoria das âncoras de carreira. Esta nova abordagem admite a existência de mais do que uma âncora de carreira dominante, suscitando assim questões ao nível das dinâmicas de proximidade ou de oposição que poderão surgir. Utilizando o Inventário de Orientações de Carreira (Career Orientations Inventory), originalmente desenvolvido por Schein (1990), e uma amostra de Engenheiros, procurou-se compreender estas dinâmicas e mapear as relações entre as âncoras de carreira, recorrendo a um estudo correlacional entre as âncoras de carreira e a uma análise de componentes principais. No final tecem-se algumas considerações, nomeadamente ao nível das limitações do presente estudo, bem como do contributo para a investigação ao nível das evidências que corroboram a reconceptualização do modelo das âncoras de carreira de Edgar Schein.Contrary to Edgar Schein’s typology which solely allows for the dominance of one career anchor, the present study follows the current line of research which suggests a reconceptualization thereof. This new approach allows for the existence of more than one dominant career anchor, thereby raising questions in terms of the dynamics of proximity or opposition which may arise. Using the Career Orientations Inventory originally developed by Schein (1990) and a sample of engineers, it was sought to understand these dynamics, mapping the relations between career anchors by means of a correlational study between the career anchors and a principal component analysis. Finally, some considerations are raised in terms of the limitations of the present study as well as the contribution to research as regards the evidence which corroborates the reconceptualization of Edgar Schein’s career anchors model

Actuator Fault Tolerant LQG Control of a Water Delivery Canal

The problem of reconfiguration of the control system to mitigate the effects of actuator faults in a water delivery canal is addressed in this paper. When a fault in an actuator is detected and isolated, the controller is reconfigured by changing the set of manipulated and process variables and using a different controller, associated to a different plant model, in a hybrid systems framework. In order to prevent instability that may be associated with switching among controllers, a dwell time condition is used. Both centralized and distributed control, a game approach is followed to coordinate the different local controllers. Experimental results are presented

O Papel da Família e do Meio no Desenvolvimento de Comportamentos Desviantes nos Jovens: As Percecões dos Técnicos

O contexto familiar é o pilar sobre o qual se baseia o desenvolvimento humano. As famílias com vulnerabilidade social e psicológica não correspondem aos papéis parentais expectáveis para um desenvolvimento saudável e para a execução de todas as necessidades dos filhos. De facto, a investigação tem repetidamente encontrado uma forte relação entre as características familiares e o desenvolvimento de competências, e o impacto negativo da adversidade sociofamiliar na adaptação psicossocial. Neste sentido, relacionam-se famílias de baixo rendimento, com vulnerabilidade social, e inseridas num meio onde a desorganização social tende a prevalecer com uma maior propensão para o aparecimento de comportamentos delinquentes nos seus membros mais jovens. O foco deste trabalho recai sobre a relação entre padrões familiares abusivos, violentos ou negligentes, bem como dos fatores do meio envolvente (comunidade), e a posterior expressão de comportamentos desviantes por parte dos jovens vítimas dessas condições. Neste trabalho é utilizado o método qualitativo, com a realização de oito entrevistas semiestruturadas a técnicos de áreas diversas. Posteriormente, no que concerne à análise de dados, foi realizada uma análise temática de acordo com Braun e Clarke (2006). Concluímos que todos os técnicos demonstraram perspetivas semelhantes e consistentes com a literatura revista, sendo que apresentaram pontos válidos e de relevância para o estudo do fenómeno apresentado. No futuro seria importante realizar estudos sobre a perspetivas dos próprios jovens, relativamente às mesmas temáticas bem como estudos longitudinais comparativos, com o objetivo de melhorar e adaptar o sistema de ação social e justiça, para que, cada vez mais, sejam derrubadas as desigualdades de oportunidades.The family context is the pillar on which human development is based. Families with social and psychological vulnerability do not correspond to the expected parental roles for healthy development and for the execution of all children's needs. In fact, research has repeatedly found a strong relationship between family characteristics and skills development, and the negative impact of socio-family adversity on psychosocial adaptation. In this sense, low-income families with social vulnerability are related and inserted in a medium where social disorganization tends to prevail with a greater propensity for the appearance of delinquent behaviors in their younger members. The focus of this work is on the relationship between abusive, violent or neglectful family patterns, as well as the factors of the surrounding environment (community), and the subsequent expression of deviant behavior on the part of the young victims of these conditions. We used the qualitative method in this work, with eight semi-structured interviews carried out with technicians from different areas. With regard to data analysis, it was performed a thematic analysis according to Braun and Clarke (2006). We concluded that all technicians showed similar perspectives consistent with the literature, and presented valid and relevant points for the study of the phenomenon presented. In the future, it would be important to undertake studies on the perspectives of young people themselves, regarding the same themes, as well as comparative longitudinal studies, with the aim of improving and adapting the system of social action and justice, so that inequalities of opportunities are increasingly overcome

Sobre a criação site-specific de um espectáculo de dança-teatro: nothing specific

Este trabalho pretende descrever e explicar o processo de criação da performance Nothing Specific. Esta criação engloba conceitos como o trabalho site-specific, a aplicação do método criativo de Anna Halprin – ciclos RSVP – e a inclusão de ferramentas de composição da dança-teatro como postuladas por Pina Bausch. Tem, como ponto de partida, os ideais estéticos de Zygmunt Bauman relativos ao amor líquido e pretende explorar a relação do ser humano com ele próprio e com os elementos naturais que o rodeiam, numa época conturbada pelo excesso de estimulação tecnológica, adormecedora de sentidos e sensações.This study intends to describe and explain the criative process of the performance Nothing Specific. This criation envolves concepts such as site-specific work, the application of Anna Halprin’s creative method – RSVP cycles – and the inclusion of tanztheater composition tools as postulated by Pina Bausch. It has, as a starting point, the aesthetic ideals of Zygmunt Bauman concerning liquid love and it intends to explore the human being’s relationship with himself and the natural elements around him, at an era conturbed by the excess of techological stimulation, wich numbs our feelings and sensations