Spanning trees with generalized degree constraints arising in the design of wireless networks

In this paper we describe a minimum spanning tree problem with generalized degree constraints which arises in the design of wireless networks. The signal strength on the receiver side of a wireless link decreases with the distance between transmitter and receiver. In order to work properly, the interference on the receiving part of the link must be under a given threshold. In order to guarantee this constraint, for each node we impose a degree constraint that depends on the ”length” of the links adjacent to the corresponding node, more precisely, nodes adjacent to long links must have a smaller degree and vice-versa. The problem is complicated by considering different signal strengths for each link. Increasing the strength in a link increases the cost of the link. However, it also reduces the maximum allowed degree on its end nodes. We create two models using adequate sets of variables, one may be considered an extended version of the other, and relate, from a theoretical perspective, the corresponding linear programming relaxations.FCT - POCTI-ISFL-1-152FCT - PTDC/EIA/64772/200

Confrontation Between Judicial Activism and State of Exception

The judiciary has excelled in the international and national scene, reaching role of great importance, thus creating opposition to the legislative and executive powers. The center of gravity of the sovereign power of the state moves toward the judiciary, that happens to have a more active role and controlling of the others powers, but also appears as a great defender of social and fundamental rights causes, seeking to make an effective constitution. Its great public notoriety has attracted great distrust of various sectors of society, especially by the two powers that have an increasing interference. Arises, therefore, a speech that the judiciary would be reversing into a big and uncontrollable power, increasing the suspicion that now it would be living in a real dictatorship of the judiciary through judicial activism. There is a growing concern with the expansion of activism and the role of the judiciary. The purpose of this work is to conceptualize and approach the judicial activism and the state of exception to search and reveal if there is any similarity, to then draw up a possible answer to the concern of forming a dictatorship of the judiciary. The state of exception is one of the rule of law paradoxes, while activism is a political manifestation of the judiciary. The similarity between the institutes appears as appalling in a dynamic expansion of political power of a state institution exercising judicial function, putting in check who would be the sovereign in a rule of law and democratic state

Relatório do 3º Fórum GDI

Relatório relativo ao 3º Fórum de Gestão de Dados de Investigação (3º Fórum GDI), evento que decorreu na Universidade do Minho, Braga, no dia 06 de novembro de 2017.Os dados obtidos com o "Inquérito de satisfação aos participantes do 3.º Fórum de Gestão de Dados de Investigação" encontram disponíveis em: https://doi.org/10.34622/datarepositorium/IRT9DGO relatório que aqui se apresenta tem por objetivo documentar o 3.º Fórum de Gestão de Dados de Investigação (3º Fórum GDI), evento que decorreu em Braga, na Universidade do Minho, no dia 06 de novembro de 2017. O 3º Fórum GDI foi, uma vez mais, uma iniciativa da Secretaria de Estado da Ciência, Tecnologia e Ensino Superior, promovida no âmbito da Política Nacional de Ciência Aberta e das atividades do RCAAP – Repositório Científico de Acesso Aberto de Portugal, organizada pela Universidade do Minho, pelo Gabinete da Secretária de Estado da Ciência, Tecnologia e Ensino Superior e FCT-FCCN – Fundação para a Ciência e Tecnologia – Fundação para a Computação Científica Nacional. Com a realização desta 3ª edição, procurou-se dar continuidade ao trabalho em curso de dinamização e criação de uma comunidade de profissionais que desenvolvem a sua atividade no suporte à gestão de dados nas instituições de investigação em Portugal. Esta terceira edição vem reforçar a necessidade de dar seguimento a este tipo de eventos, como espaço de debate e partilha de projetos, assim como contribuir para o desenvolvimento de competências, no entanto, fica patente a necessidade de envolver mais participantes e incentivar mais instituições a marcarem presença. A dinamização periódica do Fórum GDI procura capitalizar saberes e práticas, contribuindo para a melhoria e o desenvolvimento das infraestruturas, serviços e políticas associadas à gestão de dados de investigação. Este evento contou com 101 participantes efetivos, do total de 135 inscritos. Para o momento de abertura contamos com a presença de Carla Martins, Pró-reitora da Universidade do Minho, de Ana Alves Pereira, da Secretaria de Estado da Ciência, Tecnologia e Ensino Superior e de João Nuno Ferreira, FCT-FCCN – Fundação para a Ciência e Tecnologia, unidade FCCN

Multimedia Content Distribution Management Using a Distributed Topology

Advertising plays an important role in order for many companies to promote their products and services. It can be expensive to place advertisements with no guarantees that the message will reach the intended persons. In this field, targeted advertising is the mainstream strategy to captivate the potential consumer. People are used to see advertisements everywhere they go in many different forms. One of those is the use of screen displays that are believed to make the ads more engaging. However, using digital screens to advertise may lead to some issues, like down times or unwanted error messages from the device that controls the screens. This can cause a bad experience for both the target audience and the advertiser. This thesis was developed within the scope of a project called Vixtape. It’s a platform with the goal of turning any public screen into an ads displaying device and in the process reward the screen owner by exposing ads to the target audience. It also has the mission of giving the end user a optimal technological experience, no flaws and highly efficient. All these characteristics are accomplished by the use of a new open source technology called Interplanetary File System (IPFS), that allow devices to share content between them in a Peer-to-Peer (P2P) topology. This content distribution method saves Internet bandwidth to the end user (i.e., the Vixtape service client) and also enables the devices to work offline in case their Internet connection drops. This will greatly reduce the common problems seen with ads screen, thus giving a better experience to both the audience and the end user. By the end of this document one can see that, adding a distributed topology to the Vixtape platform increased the Internet usage efficiency of the ads devices by always having up-to-date content available. This avoids that a device unnecessarily requests content from any of the other devices that had previously requested it. Additionally, a strategy to target a given audience was employed in order to choose the right ads to play. This further increases the maximum potential consumers the advertisements are shown to

Assessing media literacy competences: reflections and recommendations from a quantitative study

The assessment of media literacy is a complex task, which might attempt to reconcile a research field traditionally developed within a critical paradigm with the task of evaluating and quantifying media literacy competences through essentially quantitative methods. Despite the lack of consensus regarding how to evaluate and measure media literacy, this goal is increasingly sought by political and regulatory stakeholders, as well as studied within the academic world. Based on one of such attempts, a study on the media literacy competences of 679 Portuguese teenagers, this paper presents a review and a reflection on the specific challenges posed by the intent to quantitatively assess media literacy, without neglecting its core critical dimension. It concludes by suggesting the need for methodological convergence and the continuous development of valid and reliable indicators, which must necessarily be context and subject-dependent, to improve this area of research.English proofreading funded by the Portuguese Foundation for Science and Technology through the Multiannual Funding of the Communication and Society Research Centre 2020-2023 with reference UIDB/00736/2020

Encoding and analysis of variational ROS computation graphs

Dissertação de mestrado integrado em Engenharia InformáticaIn robotic applications, it is common to develop several variants of the same system (also known as a software product line), for example, to support different configurations of a robot. ROS is the most popular framework for developing robotic applications, where each application is implemented as a distributed system of computation nodes that communicate through message passing. HAROS is a framework for static analysis of ROS-based code. It can extract an abstract model of a ROS system’s architecture (called the computation graph) and perform an analysis on that model. However, it can only analyse one configuration at a time. In this thesis, we present three different approaches for encoding various ROS computation graphs in a single variational data structure, which contains the information related to the whole system and not just a configura tion. Additionally, we also define a variational execution algorithm for each approach, along with a small query language, so that we can query and perform some analysis on said data structures. Lastly, we evaluate these algorithms and data structures so that we can reach some conclusions on which approaches work best, and in what conditions.Nas aplicações robóticas, é comum desenvolver diversas variantes do mesmo sistema (também conhecido como uma software product line) para, por exemplo, suportar diferentes configurações de um robot. O ROS é a framework mais popular no que toca ao desenvolvimento de aplicações robóticas, onde cada aplicação é implementada como um sistema distribuído de nós de computação que comunicam entre si através do envio de mensagens. O HAROS é uma framework de análise estática de código ROS. Consegue extrair um modelo abstrato de uma arquitetura de um sistema ROS (chamado grafo de computação) e executar nesse modelo uma análise. Nesta tese, apresentamos três diferentes abordagens para codificar vários grafos de computação ROS numa única estrutura de dados variacional, que contém a informação relativa a todo o sistema e não apenas a uma configuração. Adicionalmente, também definimos um algoritmo de execução variacional para cada abordagem, juntamente com uma pequena linguagem de query, de forma a que possamos analisar e pesquisar nessas estruturas de dados. Por fim, avaliámos estes algoritmos e estruturas de dados de modo a que possamos chegar a algumas conclusões sobre que abordagens funcionam melhor, e em que situações

Assessing media literacy competences: Reflections and recommendations from a quantitative study

The assessment of media literacy is a complex task, which might attempt to reconcile a research field traditionally developed within a critical paradigm with the task of evaluating and quantifying media literacy competences through essentially quantitative methods. Despite the lack of consensus regarding how to evaluate and measure media literacy, this goal is increasingly sought by political and regulatory stakeholders, as well as studied within the academic world. Based on one of such attempts, a study on the media literacy competences of 679 Portuguese teenagers, this paper presents a review and a reflection on the specific challenges posed by the intent to quantitatively assess media literacy, without neglecting its core critical dimension. It concludes by suggesting the need for methodological convergence and the continuous development of valid and reliable indicators, which must necessarily be context and subject-dependent, to improve this area of research