Nominal C-Unification

Nominal unification is an extension of first-order unification that takes into account the \alpha-equivalence relation generated by binding operators, following the nominal approach. We propose a sound and complete procedure for nominal unification with commutative operators, or nominal C-unification for short, which has been formalised in Coq. The procedure transforms nominal C-unification problems into simpler (finite families) of fixpoint problems, whose solutions can be generated by algebraic techniques on combinatorics of permutations.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

Reglamento de la Cofradía de S. Segundo establecida en su ermita del puente Adaja de la ciudad de Ávila.

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

Contributions from Neuroscience and Biology to the Philosophy of Law

This article discusses the possibility of dealing, from a scientific point of view, with ethical standards from which one can critically evaluate positive law. For a long time it was considered that such standards would be subjective, emotional, and that they would vary according to time and place. That is why it was considered impossible, especially from a positivist point of view, to examine them using a scientific approach, due to a lack of the necessary objectivity. The findings of contemporary biology and neuroscience, however, may cast new light on this debate. Although they would not resolve the debate, these findings significantly challenge the idea that moral sentiments cannot be able to be scientifically studied

The impact of lockdown announcements during the COVID-19 crisis: An event study from the Portuguese stock market

The COVID-19 pandemic impacted global financial markets in an unprecedented manner. It is well-documented the negative effect in stock markets and increased volatility caused by the preventive measures adopted to combat the disease. This study aims to analyse how lockdowns and other restrictive measures affected the Portuguese index PSI-20 and its constituents. Specially, it investigates the effect over the three first waves of COVID-19 in Portugal, using the STOXX600 European index as benchmark, between March 2020 and April 2021. To test the hypothesis of whether lockdown measures affected stock returns, an event study methodology is employed to detect the presence of abnormal returns around each event date. Using a set of 21 events and a 5-day event window for each event, the abnormal returns are analysed with parametric and nonparametric tests. The test results show a negative market response over strict lockdown announcements, and a positive response over the withdrawals of such restrictions. The results suggest investors are likely to respond negatively to government’s impositions, especially in extraordinary situations. Nevertheless, the impact declines as the period of impositions extends. In addition, the companies most affected by the Portuguese government impositions are Ibersol and EDP Renováveis, while the least affected companies are Jerónimo Martins and Pharol.A pandemia da COVID-19 teve um impacto sem precedentes nos mercados financeiros mundiais. Está bem documentado o efeito negativo nos mercados bolsistas e o aumento da volatilidade causada pelas medidas preventivas adotadas para combater a transmissão da doença. Este estudo visa analisar como os confinamentos e outras medidas preventivas afetaram o índice bolsista Português PSI-20, assim como os seus constituintes. Em especial, investiga o efeito nas três primeiras vagas da COVID-19 em Portugal, utilizando o índice Europeu STOXX600 como referência, entre Março de 2020 e Abril de 2021. Para testar a hipótese se as medidas de prevenção afetaram os retornos das ações, é utilizada uma metodologia de estudo de eventos para detetar a presença de retornos anormais durante cada evento. Utilizando um conjunto de 21 eventos e um período de 5 dias para cada evento, os retornos anormais são analisados com testes paramétricos e não paramétricos. Os resultados dos testes mostram uma resposta negativa do mercado em relação a anúncios de confinamento, e uma resposta positiva em relação à retirada de tais restrições. Os resultados sugerem que os investidores são suscetíveis de responder negativamente às restrições do governo, especialmente em situações extraordinárias. No entanto, o impacto decresce à medida que o período de restrições se estende. Adicionalmente, as empresas mais afetadas pelas imposições do governo Português são a Ibersol e a EDP Renováveis, enquanto as empresas menos afetadas são a Jerónimo Martins e a Pharol

Intrusion Detection Systems in SDN-based Self-Healing PMU Networks

Nowadays, Power grids are critical infrastructures on which everything else relies, and their correct behavior is of the highest priority. New smart devices are being deployed to be able to manage and control power grids more efficiently and avoid instability. However, the deployment of such smart devices like Phasor Measurement Units (PMU) and Phasor Data Concentrators (PDC), open new opportunities for cyber attackers to exploit network vulnerabilities. If a PDC is compromised, all data coming from PMUs to that PDC is lost, reducing network observability. Our approach to solve this problem is to develop an Intrusion detection System (IDS) in a Software-defined network (SDN). allowing the IDS system to detect compromised devices and use that information as an input for a self-healing SDN controller, which redirects the data of the PMUs to a new, uncompromised PDC, maintaining the maximum possible network observability at every moment. During this research, we have successfully implemented Self-healing in an example network with an SDN controller based on Ryu controller. We have also assessed intrinsic vulnerabilities of Wide Area Management Systems (WAMS) and SCADA networks, and developed some rules for the Intrusion Detection system which specifically protect vulnerabilities of these networks. The integration of the IDS and the SDN controller was also successful. \\To achieve this goal, the first steps will be to implement an existing Self-healing SDN controller and assess intrinsic vulnerabilities of Wide Area Measurement Systems (WAMS) and SCADA networks. After that, we will integrate the Ryu controller with Snort, and create the Snort rules that are specific for SCADA or WAMS systems and protocols

Computation of the optimal relative pose between overlapping grid maps through discrepancy minimization

Grid maps are a common environment representation in mobile robotics. Many Simultaneous Localization and Mapping (SLAM) solutions divide the global map into submaps, forming some kind of graph or tree to represent the structure of the environment, while the metric details are captured in the submaps. This work presents a novel algorithm that is able to compute a physically feasible relative pose between two overlapping grid maps. Our algorithm can be used for correspondence search (data association), but also for integrating negative information in a unified way. This paper proposes a discrepancy measure between two overlapping grid maps and its application in a quasi Newton optimization algorithm, with the hypothesis that minimizing such discrepancy could provide useful information for SLAM. Experimental evidence is provided showing the high potential of the algorithm

Juristas aragoneses en el final del Antiguo Régimen: los Pascual de Torla de la ciudad de Alcañiz

Se realiza una visión sobre una familia de juristas de Alcañiz, los Pascual de Torla, desde don Nicolás Pascual, abogado, hasta su hijo don Mariano Pascual, jurista además de político, sin olvidar sus otros cuatro hermanos, dedicados a partes iguales, los dos primeros a la milicia y los otros dos a la vida religiosa.A vision on a family of jurists from Alcañiz, the Pascual de Torla, beginning with Nicolás Pascual, lawyer, to his son Mariano Pascual, jurist as well as politician, without forgetting his other four brothers, who were dedicated to the militia (the first two ones) and the other two to the religious life.On effectue une vision sur une famille de juristes d’Alcañiz, les Pascual de Torla, dès Nicolás Pascual, avocat, jusqu’à son fils Mariano Pascual, juriste et en outre politicien, sans oublier ses quatre autres frères, les deux premiers consacrés à la milice et les deux autres à la vie religieuse

Fast processing of grid maps using graphical multiprocessors

Grid mapping is a very common technique used in mobile robotics to build a continuous 2D representation of the environment useful for navigation purposes. Although its computation is quite simple and fast, this algorithm uses the hypothesis of a known robot pose. In practice, this can require the re-computation of the map when the estimated robot poses change, as when a loop closure is detected. This paper presents a parallelization of a reference implementation of the grid mapping algorithm, which is suitable to be fully run on a graphics card showing huge processing speedups (up to 50×) while fully releasing the main processor, which can be very useful for many Simultaneous Localization and Mapping algorithms

Promotion and remuneration of university professors: from the LRU to the COU

This paper analyzes policy changes introduced by a law in 2001 regarding selection and remuneration of university professors. The effects of the previous law, passed in 1983, are described, as well as the likely consequences of the new law. Economic analysis is combined with a comparison of the models applied in different developed countries.professors, incentives, universities.