983 resultados para intermodal transportation problem


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China’s impressive economic growth has led to the accumulation of massive financial assets. The emergence of sovereign wealth funds (SWFs), as a governmental investment device for its excessive foreign reserves, symbolizes a major rebalancing of economic power. With its investment portfolios drastically diversified for well-established financial institutions as well as some strategic sectors, a seminal debate seems centered on whether China’s SWFs are in furtherance of purely commercial or geopolitically strategic purposes. Under the sophisticated hard laws associated with international initiatives, it is unlikely that the SWFs-related investment would distort the global financial system, and genuinely threaten national security, which assumption may only exist at a hypothetical level. The potential protectionism would inevitably retard the world economy’s recovery, were it not to be proportionately addressed. A most significant necessity appears to be to strike a proportionate balance between sustaining the credibility of open investment environment and efficiently minimizing implications of SWFs political arenas.

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The history of publishing legal decisions (law reporting) in the UK has been that of a privatised system since its inception, and that history has encompassed several hundred years. The privatised nature of this has meant that the product (the law report) has been, except in limited cases, viewed as the property of the publisher, rather than the property of the court or public. BAILII is an open access legal database that came about in part because of the copyrighted, privatised nature of this legal information. In this paper, we will outline the problem of access to pre-2000 judgments in the UK and consider whether there are legal or other remedies which might enable BAILII to both develop a richer historic database and also to work in harmony, rather than in competition, with legal publishers. We argue that public access to case law is an essential requirement in a democratic common law system, and that BAILII should be seen as a potential step towards a National Law Library.

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This paper describes the development of a novel metaheuristic that combines an electromagnetic-like mechanism (EM) and the great deluge algorithm (GD) for the University course timetabling problem. This well-known timetabling problem assigns lectures to specific numbers of timeslots and rooms maximizing the overall quality of the timetable while taking various constraints into account. EM is a population-based stochastic global optimization algorithm that is based on the theory of physics, simulating attraction and repulsion of sample points in moving toward optimality. GD is a local search procedure that allows worse solutions to be accepted based on some given upper boundary or ‘level’. In this paper, the dynamic force calculated from the attraction-repulsion mechanism is used as a decreasing rate to update the ‘level’ within the search process. The proposed method has been applied to a range of benchmark university course timetabling test problems from the literature. Moreover, the viability of the method has been tested by comparing its results with other reported results from the literature, demonstrating that the method is able to produce improved solutions to those currently published. We believe this is due to the combination of both approaches and the ability of the resultant algorithm to converge all solutions at every search process.

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The problem of diffraction of an optical wave by a 2D periodic metal aperture array with square, circular, and ring apertures is solved with allowance for the finite permittivity of a metal in the optical band. The correctness of the obtained results is verified through comparison with experimental data. It is shown that the transmission coefficient can be substantially greater than the corresponding value reached in the case of diffraction by a grating in a perfectly conducting screen.

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Universities aim for good “Space Management” so as to use the teaching space efficiently. Part of this task is to assign rooms and time-slots to teaching activities with limited numbers and capacities of lecture theaters, seminar rooms, etc. It is also common that some teaching activities require splitting into multiple events. For example, lectures can be too large to fit in one room or good teaching practice requires that seminars/tutorials are taught in small groups. Then, space management involves decisions on splitting as well as the assignments to rooms and time-slots. These decisions must be made whilst satisfying the pedagogic requirements of the institution and constraints on space resources. The efficiency of such management can be measured by the “utilisation”: the percentage of available seat-hours actually used. In many institutions, the observed utilisation is unacceptably low, and this provides our underlying motivation: to study the factors that affect teaching space utilisation, with the goal of improving it. We give a brief introduction to our work in this area, and then introduce a specific model for splitting. We present experimental results that show threshold phenomena and associated easy-hard-easy patterns of computational difficulty. We discuss why such behaviour is of importance for space management.

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