1000 resultados para Global Illumination
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Locating and identifying points as global minimizers is, in general, a hard and time-consuming task. Difficulties increase in the impossibility of using the derivatives of the functions defining the problem. In this work, we propose a new class of methods suited for global derivative-free constrained optimization. Using direct search of directional type, the algorithm alternates between a search step, where potentially good regions are located, and a poll step where the previously located promising regions are explored. This exploitation is made through the launching of several instances of directional direct searches, one in each of the regions of interest. Differently from a simple multistart strategy, direct searches will merge when sufficiently close. The goal is to end with as many direct searches as the number of local minimizers, which would easily allow locating the global extreme value. We describe the algorithmic structure considered, present the corresponding convergence analysis and report numerical results, showing that the proposed method is competitive with currently commonly used global derivative-free optimization solvers.
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Comunicação apresentada no 27th International Congress of Administrative Sciences "Global Competitiveness and Public Administration: implications for education and training" em Abu Dhai, United Arb Emirates de 9 a 14 de Julho de 2007.
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Dissertation presented to obtain the degree of Doctor of Philosophy in Electrical Engineering, speciality on Perceptional Systems, by the Universidade Nova de Lisboa, Faculty of Sciences and Technology
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Dissertação apresentada para obtenção do grau de doutor em Biologia pelo Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa
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This paper addresses the issue of restructuring the information professional in the global economy. This restructuring is justified by a tripartite explanation: the redesign understood as innovation and disciplinary change, the reorganization of institutions conditioned by the development of information technology and economic deflation interpreted as eliminating jobs. To understand this restructuring scenario multigenerational work contexts information services are also addressed. These work contexts represent a search for understanding and to overcome common referential differences, by baby boomer practitioners and digital natives. The issue of tension and challenge between the specific technical skills and flexibility to adapt to ever-changing organizations is another topic for reflection and serves to point out new paths for the restructuring of the information professional.
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The following contribution considers whether global restructuring creates new forms of the division of labor. On the basis of empirical data from a comparative project in 14 European countries, the author supports the hypothesis that in addition to the ongoing process of the internationalization of work, there are ‘hidden’ effects at the local level. From the perspective of three occupational clusters, dynamics can be observed which have differing impacts on the occupational groups. Thus, there is a simultaneous process of restructuring and redefining skills, labor processes and the working organization which forms the daily reality of working men and women.
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Starting from theoretical perspectives on globalisation, the following article analyses how current working conditions are affected by globalisation processes. For this purpose, recent developments in the German clothing sector are traced back to the power of economic globalisation processes. Characterising the German clothing sector as pioneer in economic globalisation, we use empirical findings to illustrate how current processes of globalisation influence the work place: At organisational level, corporate strategies aim at rationalisation, standardisation and flexibilisation of work in order to response to the economic pressure of global markets. At individual level these strategies, in turn, speed up working processes and intensify working processes for the employees. Although these developments form strong trends, we conclude that the local embeddedness of companies is still of high importance with regard to organisational and individual consequences of globalisation.
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O presente trabalho aborda a temática da eficiência energética em sistemas de iluminação pública. A principal motivação prende-se com o peso significativo que a parcela energética destes sistemas ocupa na economia mundial. O uso eficiente de energia é uma crescente preocupação devido à diminuição de recursos, às consequências climáticas cada vez mais marcadas e ao elevado custo da energia, representando ainda um papel fundamental ao nível económico e de competitividade. A Iluminação Pública (IP) representa um peso importante nas despesas correntes dos municípios. É assim importante encontrar uma solução que permita manter níveis de segurança e conforto necessários às populações e que proporcione uma redução substancial do peso da IP nas despesas municipais. Neste sentido, este trabalho propõe-se estudar esta problemática, apresentando uma sistematização de soluções eficientes, quer a nível de lâmpadas e luminárias como também ao nível de tecnologias que auxiliem e complementem a eficiência de uma instalação de iluminação pública. A dissertação está dividida em duas partes. A primeira parte sistematiza os consumos verificados em Portugal, a vários níveis (consumo de energia elétrica, evolução do consumo energético de iluminação pública, etc.) abordando as políticas de eficiência energética, e são descritos alguns procedimentos que possibilitam a poupança energética na iluminação pública, aliada a instalações eficientes. A segunda parte da dissertação contempla o estudo de um caso prático cujo objetivo é propor soluções técnicas que permitam melhorar a eficiência energética na iluminação pública de Esposende, face à situação atual do concelho. Serão propostas várias soluções, tais como luminárias LED, balastros electrónicos reguláveis, lâmpadas de menor consumo e até mesmo o uso da telegestão.
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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, para a obtenção Engenharia Informática
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pp. 245-284
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This article introduces schedulability analysis for global fixed priority scheduling with deferred preemption (gFPDS) for homogeneous multiprocessor systems. gFPDS is a superset of global fixed priority pre-emptive scheduling (gFPPS) and global fixed priority non-pre-emptive scheduling (gFPNS). We show how schedulability can be improved using gFPDS via appropriate choice of priority assignment and final non-pre-emptive region lengths, and provide algorithms which optimize schedulability in this way. Via an experimental evaluation we compare the performance of multiprocessor scheduling using global approaches: gFPDS, gFPPS, and gFPNS, and also partitioned approaches employing FPDS, FPPS, and FPNS on each processor.
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This paper applies Pseudo Phase Plane (PPP) and Fractional Calculus (FC) mathematical tools for modeling world economies. A challenging global rivalry among the largest international economies began in the early 1970s, when the post-war prosperity declined. It went on, up to now. If some worrying threatens may exist actually in terms of possible ambitious military aggression, invasion, or hegemony, countries’ PPP relative positions can tell something on the current global peaceful equilibrium. A global political downturn of the USA on global hegemony in favor of Asian partners is possible, but can still be not accomplished in the next decades. If the 1973 oil chock has represented the beginning of a long-run recession, the PPP analysis of the last four decades (1972–2012) does not conclude for other partners’ global dominance (Russian, Brazil, Japan, and Germany) in reaching high degrees of similarity with the most developed world countries. The synergies of the proposed mathematical tools lead to a better understanding of the dynamics underlying world economies and point towards the estimation of future states based on the memory of each time series.
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Presented at 23rd International Conference on Real-Time Networks and Systems (RTNS 2015). 4 to 6, Nov, 2015, Main Track. Lille, France.
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Tese de Doutoramento em Relações Internacionais