972 resultados para Pareto-Koopmans global efficiency


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The constrained battery power of mobile devices poses a serious impact on user experience. As an increasingly prevalent type of applications in mobile cloud environments, location-based applications (LBAs) present some inherent limitations concerning energy. For example, the Global Positioning System based positioning mechanism is well-known for its extremely power-hungry attribute. Due to the severity of the issue, considerable researches have focused on energy-efficient locating sensing mechanism in the last a few years. In this paper, we provide a comprehensive survey of recent work on low-power design of LBAs. An overview of LBAs and different locating sensing technologies used today are introduced. Methods for energy saving with existing locating technologies are investigated. Reductions of location updating queries and simplifications of trajectory data are also mentioned. Moreover, we discuss cloud-based schemes in detail which try to develop new energy-efficient locating technologies by leveraging the cloud capabilities of storage, computation and sharing. Finally, we conclude the survey and discuss the future research directions. © 2013 Springer-Verlag Wien.

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Application of optimization algorithm to PDE modeling groundwater remediation can greatly reduce remediation cost. However, groundwater remediation analysis requires a computational expensive simulation, therefore, effective parallel optimization could potentially greatly reduce computational expense. The optimization algorithm used in this research is Parallel Stochastic radial basis function. This is designed for global optimization of computationally expensive functions with multiple local optima and it does not require derivatives. In each iteration of the algorithm, an RBF is updated based on all the evaluated points in order to approximate expensive function. Then the new RBF surface is used to generate the next set of points, which will be distributed to multiple processors for evaluation. The criteria of selection of next function evaluation points are estimated function value and distance from all the points known. Algorithms created for serial computing are not necessarily efficient in parallel so Parallel Stochastic RBF is different algorithm from its serial ancestor. The application for two Groundwater Superfund Remediation sites, Umatilla Chemical Depot, and Former Blaine Naval Ammunition Depot. In the study, the formulation adopted treats pumping rates as decision variables in order to remove plume of contaminated groundwater. Groundwater flow and contamination transport is simulated with MODFLOW-MT3DMS. For both problems, computation takes a large amount of CPU time, especially for Blaine problem, which requires nearly fifty minutes for a simulation for a single set of decision variables. Thus, efficient algorithm and powerful computing resource are essential in both cases. The results are discussed in terms of parallel computing metrics i.e. speedup and efficiency. We find that with use of up to 24 parallel processors, the results of the parallel Stochastic RBF algorithm are excellent with speed up efficiencies close to or exceeding 100%.

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In an economy which primitives are exactly those in Mirrlees (1971), we investigate the efficiency of labor income tax schedules derived under the equal sacrifice principle. Starting from a given government revenue level, we use Werning’s (2007b) approach to assess whether there is an alternative tax schedule to the one derived under the equal sacrifice principle that raises more revenue while delivering less utility to no one. For our preferred parametrizations of the problem we find that inefficiency only arises at very high levels of income. We also show how the multipliers of the Pareto problem may be extracted from the data and used to find the implicit marginal social weights associated with each level of income.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A novel common Tabu algorithm for global optimizations of engineering problems is presented. The robustness and efficiency of the presented method are evaluated by using standard mathematical functions and hy solving a practical engineering problem. The numerical results show that the proposed method is (i) superior to the conventional Tabu search algorithm in robustness, and (ii) superior to the simulated annealing algorithm in efficiency. (C) 2001 Elsevier B.V. B.V. All rights reserved.

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This paper proposes an alternative codification to solve the service restoration in electric power distribution networks using a SPEA2 multiobjective evolutionary algorithm, assuming the minimization of both the load not supplied and the number of switching operations involved in the restoration plan. Constrains as the line, power source and voltage drop limits in order to avoid the activation of protective devices are all included in the proposed algorithm. Experimental results have shown the convenience on considering these new representations in the sense of feasibility maintenance and also in the sense of better approximation to the Pareto set. ©2009 IEEE.

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One of the consequences of the opening of the worlds economies - an integral part of globalization - is increased focus on the efficiency and costs of transport services (on which competitiveness is largely dependent). Countries with inefficient and costly transport services lose out, in terms of economic activity and income, to those with more appropriate transport services. The issue is particularly important in Latin America, where exports mainly consist of bulk consignments of products with comparatively low value/quantity ratios and transport costs are a major determining factor of c.i.f. prices.The determination of competitiveness indices in the long term, however, also needs to include the costs of pollution, congestion and accidents, in addition to the transport costs usually considered as part of the price of freight. Competitiveness, efficiency and the global costs of transport were the main subjects of an international seminar organized in conjunction with the Chilean Institute of Engineers and held on 9 and 10 September 2004 at the Headquarters of the Economic Commission for Latin America and the Caribbean (ECLAC).

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O método de empilhamento por Superfície de Reflexão Comum (SRC) produz seções simuladas de afastamento nulo (AN) por meio do somatório de eventos sísmicos dos dados de cobertura múltipla contidos nas superfícies de empilhamento. Este método não depende do modelo de velocidade do meio, apenas requer o conhecimento a priori da velocidade próxima a superfície. A simulação de seções AN por este método de empilhamento utiliza uma aproximação hiperbólica de segunda ordem do tempo de trânsito de raios paraxiais para definir a superfície de empilhamento ou operador de empilhamento SRC. Para meios 2D este operador depende de três atributos cinemáticos de duas ondas hipotéticas (ondas PIN e N), observados no ponto de emergência do raio central com incidência normal, que são: o ângulo de emergência do raio central com fonte-receptor nulo (β0) , o raio de curvatura da onda ponto de incidência normal (RPIN) e o raio de curvatura da onda normal (RN). Portanto, o problema de otimização no método SRC consiste na determinação, a partir dos dados sísmicos, dos três parâmetros (β0, RPIN, RN) ótimos associados a cada ponto de amostragem da seção AN a ser simulada. A determinação simultânea destes parâmetros pode ser realizada por meio de processos de busca global (ou otimização global) multidimensional, utilizando como função objetivo algum critério de coerência. O problema de otimização no método SRC é muito importante para o bom desempenho no que diz respeito a qualidade dos resultados e principalmente ao custo computacional, comparado com os métodos tradicionalmente utilizados na indústria sísmica. Existem várias estratégias de busca para determinar estes parâmetros baseados em buscas sistemáticas e usando algoritmos de otimização, podendo estimar apenas um parâmetro de cada vez, ou dois ou os três parâmetros simultaneamente. Levando em conta a estratégia de busca por meio da aplicação de otimização global, estes três parâmetros podem ser estimados através de dois procedimentos: no primeiro caso os três parâmetros podem ser estimados simultaneamente e no segundo caso inicialmente podem ser determinados simultaneamente dois parâmetros (β0, RPIN) e posteriormente o terceiro parâmetro (RN) usando os valores dos dois parâmetros já conhecidos. Neste trabalho apresenta-se a aplicação e comparação de quatro algoritmos de otimização global para encontrar os parâmetros SRC ótimos, estes são: Simulated Annealing (SA), Very Fast Simulated Annealing (VFSA), Differential Evolution (DE) e Controlled Rando Search - 2 (CRS2). Como resultados importantes são apresentados a aplicação de cada método de otimização e a comparação entre os métodos quanto a eficácia, eficiência e confiabilidade para determinar os melhores parâmetros SRC. Posteriormente, aplicando as estratégias de busca global para a determinação destes parâmetros, por meio do método de otimização VFSA que teve o melhor desempenho foi realizado o empilhamento SRC a partir dos dados Marmousi, isto é, foi realizado um empilhamento SRC usando dois parâmetros (β0, RPIN) estimados por busca global e outro empilhamento SRC usando os três parâmetros (β0, RPIN, RN) também estimados por busca global.

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Nowadays, there is a need for improvements in production processes for companies to be competitive, as it is an obligation of businesses, it is necessary to know about the production processes accurately, to learn where improvements in work and thus have large impacts results. The calculation of efficiency of production lines is necessary to know as much about the progress of production and for product costing, when the measurement is not suitable, it generates negative impacts on the company. Due to the impact generated by this parameter, the graduation work carry out the study of change in a method that does not include all requirements necessary, by another method known as Overall Equipment Effectiveness, and according to studies, covering various parameters, showing become more consistent. These values are contained in the pattern production which is used to fund the product, thereby also occur financial impacts. Thus the work will study the change along with the analysis of impacts caused by the change

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Considering the high competitivity in the market, the application of quantitative methods can assist in analyzing the efficiency of production facilities of areas of export and import processes of the chemical industry sector. In this sense, this work aims to apply the model GPDEA-BCC optimization in order to develop an analysis of the production units of this chemical industry. So, were chosen variables relevant to the process and elaborated a final comparison between the results obtained by the optimization tool and performance indexes provided by the company. These results indicated that some production units should be monitored more carefully because some of them had a low efficiency when analyzed with multi criteria