Solving a signalized traffic intersection problem with an hyperbolic penalty function

Mathematical Program with Complementarity Constraints (MPCC) finds many applications in fields such as engineering design, economic equilibrium and mathematical programming theory itself. A queueing system model resulting from a single signalized intersection regulated by pre-timed control in traffic network is considered. The model is formulated as an MPCC problem. A MATLAB implementation based on an hyperbolic penalty function is used to solve this practical problem, computing the total average waiting time of the vehicles in all queues and the green split allocation. The problem was codified in AMPL.

Este luminoso e magnifico céu azul

Num texto de cariz jornalístico, escrito na plena maturidade da sua vida literária, em 1895, Eça de Queirós reflecte irónica e liricamente sobre a chamada ―influência‖ do clima sobre a mentalidade, a cultura e a economia dos povos europeus. É seu pretexto uma cómica palinódia dos seus sarcasmos juvenis acerca de um romântico desabafo poético-político de um ex-primeiro-ministro português, o qual enaltecia, como principal riqueza nacional, ―o luminoso e magnífico céu azul que nos cobre!‖. Já desde a década de 1870, no advento da sua vida de escritor, que, para Eça, é tema recorrente uma espécie de ―mitologia do sul‖, em que impera a tutela benfazeja e doce do céu meridional. Nesta crónica, no fim da sua vida, Eça de Queirós retoma e desenvolve, definitivamente, uma representação cultural e psicológica do clima meridional, pretexto para uma magnífica síntese contrastiva sobre o Norte e o Sul da Europa, uma enternecida apologia do sol, do calor e da luz dos climas ―ricos‖, saudosamente evocados durante um Inverno sombrio em Paris. É justamente a coerência exemplar deste motivo – associada, não obstante, à natural e estratégica evolução estético-ideológica do autor – que será objecto de reflexão deste texto: porque o signo climático e a oposição Norte/ Sul podem funcionar como noções heurísticas de uma obra e de um autor sobre os quais (como sobre Flaubert) já se disse muito, mas nunca se diz o suficiente.

Harmónicos em Instalações Eléctricas. Causas, efeitos e normalização

Jean Baptiste Joseph, barão de Fourier, publicou em Paris no ano de 1822 a sua ópera magna “Théorie Analytique de la Chaleur”. Nesta obra Fourier demonstrava que a condução do calor nos corpos sólidos podia ser descrita através de uma série infinita de senos e co‐senos. O trabalho estimulou investigações nos mais variados campos da ciência e da técnica, tendo ressaltado que o tipo de formulação matemática empregada por Fourier era um pré‐requisito para a solução de fenómenos que exibiam natureza periódica. O método de exprimir funções periódicas em termos de somas de senos e co‐senos recebe o nome de Análise Harmónica. O princípio de Fourier é basicamente o seguinte: sendo dado um sinal (função) periódico representá‐lo como série de senos e co‐senos. Obviamente que se o sinal já for um seno ou co‐seno nada mais haverá para dizer (eventualmente, um termo médio não‐nulo); mas o nosso intuito é o de extrair informação de onde a haja, i.e., de funções não‐sinusoidais. Aos vários termos da série de Fourier, cada um deles de argumento múltiplo inteiro do período da função original, dá‐se‐lhes o nome de harmónicos, sendo a ordem destes precisamente o valor desse múltiplo.

Dynamics of a backlash chain

This paper studies the dynamical properties of a system with distributed backlash and impact phenomena. This means that it is considered a chain of masses that interact with each other solely by means of backlash and impact phenomena. It is observed the emergence of non-linear phenomena resembling those encountered in the Fermi-Pasta-Ulam problem.

Self-similarity principle: the reduced description of randomness

A new general fitting method based on the Self-Similar (SS) organization of random sequences is presented. The proposed analytical function helps to fit the response of many complex systems when their recorded data form a self-similar curve. The verified SS principle opens new possibilities for the fitting of economical, meteorological and other complex data when the mathematical model is absent but the reduced description in terms of some universal set of the fitting parameters is necessary. This fitting function is verified on economical (price of a commodity versus time) and weather (the Earth’s mean temperature surface data versus time) and for these nontrivial cases it becomes possible to receive a very good fit of initial data set. The general conditions of application of this fitting method describing the response of many complex systems and the forecast possibilities are discussed.

Fractional order modelling of zero length column desorption response for adsorbents with variable particle sizes

This manuscript analyses the data generated by a Zero Length Column (ZLC) diffusion experimental set-up, for 1,3 Di-isopropyl benzene in a 100% alumina matrix with variable particle size. The time evolution of the phenomena resembles those of fractional order systems, namely those with a fast initial transient followed by long and slow tails. The experimental measurements are best fitted with the Harris model revealing a power law behavior.

Job phasing aware preemption deferral

Preemptions account for a non-negligible overhead during system execution. There has been substantial amount of research on estimating the delay incurred due to the loss of working sets in the processor state (caches, registers, TLBs) and some on avoiding preemptions, or limiting the preemption cost. We present an algorithm to reduce preemptions by further delaying the start of execution of high priority tasks in fixed priority scheduling. Our approaches take advantage of the floating non-preemptive regions model and exploit the fact that, during the schedule, the relative task phasing will differ from the worst-case scenario in terms of admissible preemption deferral. Furthermore, approximations to reduce the complexity of the proposed approach are presented. Substantial set of experiments demonstrate that the approach and approximations improve over existing work, in particular for the case of high utilisation systems, where savings of up to 22% on the number of preemption are attained.

EMMON: a WSN system architecture for large scale and dense real-time embedded monitoring

Wireless sensor networks (WSNs) have attracted growing interest in the last decade as an infrastructure to support a diversity of ubiquitous computing and cyber-physical systems. However, most research work has focused on protocols or on specific applications. As a result, there remains a clear lack of effective, feasible and usable system architectures that address both functional and non-functional requirements in an integrated fashion. In this paper, we outline the EMMON system architecture for large-scale, dense, real-time embedded monitoring. EMMON provides a hierarchical communication architecture together with integrated middleware and command and control software. It has been designed to use standard commercially-available technologies, while maintaining as much flexibility as possible to meet specific applications requirements. The EMMON architecture has been validated through extensive simulation and experimental evaluation, including a 300+ node test-bed, which is, to the best of our knowledge, the largest single-site WSN test-bed in Europe to date.

Data mining languages for business intelligence

Doctoral Thesis in Information Systems and Technologies Area of Engineering and Manag ement Information Systems

Some reflections on acquisition, processing and analysis of statistical data in forest soils

Beyond the classical statistical approaches (determination of basic statistics, regression analysis, ANOVA, etc.) a new set of applications of different statistical techniques has increasingly gained relevance in the analysis, processing and interpretation of data concerning the characteristics of forest soils. This is possible to be seen in some of the recent publications in the context of Multivariate Statistics. These new methods require additional care that is not always included or refered in some approaches. In the particular case of geostatistical data applications it is necessary, besides to geo-reference all the data acquisition, to collect the samples in regular grids and in sufficient quantity so that the variograms can reflect the spatial distribution of soil properties in a representative manner. In the case of the great majority of Multivariate Statistics techniques (Principal Component Analysis, Correspondence Analysis, Cluster Analysis, etc.) despite the fact they do not require in most cases the assumption of normal distribution, they however need a proper and rigorous strategy for its utilization. In this work, some reflections about these methodologies and, in particular, about the main constraints that often occur during the information collecting process and about the various linking possibilities of these different techniques will be presented. At the end, illustrations of some particular cases of the applications of these statistical methods will also be presented.

Práticas educativas e internamento de jovens em Portugal na transição do século XIX para o século XX - A Colónia agrícola correcional de Vila Fernando

Inaugurada em 1895 junto a Elvas, a Colónia Agrícola Correcional de Vila Fernando procurava a regeneração de jovens por meio do trabalho, buscando também acabar com as péssimas condições a que estavam sujeitos os jovens ao serem encarcerados com os adultos, nas cadeias do país. Analisaremos, no período compreendido entre finais do século XIX e início do século XX, os diferentes processos educativos presentes no quotidiano da instituição, nas práticas do trabalho, da formação profissional e do ensino escolar, procurando averiguar, numa perspetiva histórico-pedagógica, de que modo a instituição foi capaz de conciliar o carácter disciplinador do trabalho com a reintegração social.