769 resultados para motorway congestion


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Backbone networks are responsible for long-haul data transport serving many clients with a large volume of data. Since long-haul data transport service must rely on a robust high capacity network the current technology broadly adopted by the industry is Wavelength Division Multiplexing (WDM). WDM networks enable one single ber to operate with multiple high capacity channels, drastically increasing the ber capacity. In WDM networks each channel is associated with an individual wavelength. Therefore a whole wavelength capacity is assigned to a connection, causing waste of bandwidth in case the connection bandwidth requirement is less than the channel total capacity. In the last half decade, Elastic Optical Networks (EON) have been proposed and developed based on the fexible use of the optical spectrum known as the exigrid. EONs are adaptable to clients requirements and may enhance optical networks performance. For these reasons, research community and data transport providers have been demonstrating increasingly high interest in EONs which are likely to replace WDM as the universally adopted technology in backbone networks in the near future. EONs have two characteristics that may limit its ecient resources use. The spectrum fragmentation, inherent to the dynamic EON operation, decrease the network capacity to assign resources to connection requests increasing network blocking probability. The spectrum fragmentation also intensifides the denial of service to higher rate request inducing service unfairness. Due to the fact EONs were just recently developed and proposed, the aforementioned issues were not yet extensively studied and solutions are still being proposed. Furthermore, EONs do not yet provide specific features as differentiated service mechanisms. Differentiated service strategies are important in backbone networks to guarantee client\'s diverse requirements in case of a network failure or the natural congestion and resources contention that may occur at some periods of time in a network. Impelled by the foregoing facts, this thesis objective is three-fold. By means of developing and proposing a mechanism for routing and resources assignment in EONs, we intend to provide differentiated service while decreasing fragmentation level and increasing service fairness. The mechanism proposed and explained in this thesis was tested in a EON simulation environment and performance results indicated that it promotes beneficial performance enhancements when compared to benchmark algorithms.

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Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

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Sufficient cross‐border electricity transmission infrastructure is a pre‐requisite for a functioning European internal market for electricity. Also, the achievement of the EU’s energy policy objectives – sustainability, competitiveness and security of supply – critically depends on adequate investment in physical interconnections between the member states. Mainly focusing on the “regulatory path”, this paper assesses different ways to achieve a sufficient level of interconnector investment. In a first step, economic analysis identifies numerous impediments to interconnector investment adding up to an “interconnector investment failure”. Reflecting on the proper regulatory design of an EU framework able to overcome the interconnector investment failure, a number of recommendations are put forward:  All congestion rents should be channeled into interconnector building. Unused rents should be transferred to a European interconnector fund supervised by an EU agency.  Even though inherently sub‐optimal, merchant transmission investment can be used as a means to put pressure on regulated transmission system operators (TSO) that do not deliver. An EU agency should have exclusive competence on merchant interconnector exemptions.  A European TSO organization should be entrusted with supra‐national network planning, supervised by an EU agency.  The agency should decide on investment cost reallocation for interconnector projects that yield strong externalities. Payments could be settled via a European interconnector fund.  In case of non‐compliance with the supra‐national network plan, the EU agency should have the right to organize a tender – financed by the European interconnector fund – in order to get the “missing link” built. Assessing the existing EU regulatory framework, the efforts of the 2009 “third energy package” to fill the “regulatory gap” with new EU bodies – ACER and ENTSO‐E – are acknowledged. However, striking holes in regulatory framework are spotted, notably with regard to the use of congestion rents, interconnector cost allocation, and the distribution of decision making powers on new infrastructure exemptions A discussion of the TEN‐E interconnector funding scheme shows that massive funding can be an interim solution to the problem of insufficient interconnection capacities while overcoming the political deadlock on sensible regulatory topics such as interconnector cost allocation. The paper ends with policy recommendations.

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O baço tem importantes funções hematopoiéticas e imunológicas, desempenhando um papel crucial na reposição da hipovolemia e de volume sanguíneo, em situações de hemorragia aguda. A administração de soluções fisiológicas tem grande importância na correção do volume circulante, evitando as complicações de hipovolemia. Este trabalho tem como objetivo avaliar as alterações provocadas no baço, após grave hemorragia dos suínos e reperfusão, utilizando duas soluções fisiológicas distintas, um cristaloide - solução de ringer lactato e um coloide - solução de hidroxietilamido. As lesões histopatológicas encontradas no baço foram congestão, hiperplasia da polpa branca, a notoriedade dos elipsoides e o infiltrado inflamatório, razão pela qual, se procedeu à sua avaliação semi-quantitativa. Relativamente à hiperplasia da polpa branca, foram encontradas diferenças estatisticamente significativas entre o grupo Ringer Lactato e o grupo Hidroxietilamido, verificando-se o aumento da hiperplasia da polpa branca no grupo Ringer Lactato. Quanto à área dos elipsoides, apenas um suíno em cada grupo registava grau 1. Houve uma preponderância do grau 2 no grupo de controlo (n = 5) e no grupo Ringer Lactato (n = 11), enquanto que no grupo Hidroxietilamido se registaram valores idênticos para os graus 2 e 3 (n = 5). A congestão ocorreu em todos os grupos, com predomínio do grau 2 (n = 7) nos grupos Ringer Lactato e Hidroxietilmido. Relativamente ao infiltrado inflamatório, no grupo de controlo predominou o grau 1 (n = 5) e registou-se a prevalência do grau 2 no grupo Ringer Lactato (n = 8) e no grupo Hidroxietilamido (n = 9). A área dos elipsoides variou nos diferentes grupos, não tendo revelado diferenças significativas entre os grupos. Foi observada congestão nos três grupos do estudo, não tendo sido, contudo, registadas diferenças significativas entre os grupos. Quanto ao infiltrado inflamatório, verificou-se que no grupo de controlo predominou o grau 1, enquanto que nos grupos Ringer Lactato e Hidroxietilamido prevaleceu o grau 2, o que se justifica pelo facto dos grupos Ringer Lactato e Hidroxietilamido terem sido submetidos a uma hemorragia. Foi assim possível concluir que a reperfusão volémica com Hidroxietilamido 130/0.4 pode reduzir a hiperreatividade esplénica, quando comparado com o Ringer Lactato, após hemorragia aguda. Verificamos que os elipsoides não sofrem qualquer afetação em situações de alterações hemodinâmicos. Atualizamos um sistema de classificação para avaliação de congestão esplénica, usando o modelo suíno. Aferimos que as situações causadoras de alterações hemodinâmicas ou da perfusão tecidual provocam aumento do infiltrado inflamatório.

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Mode of access: Internet.

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"Publication no. 58; November 1939."

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"These bills relate to the same general subject. It involves the question of trying to devise some method of relieving the congestion of business in the United States District courts."--p.

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Texas Department of Transportation, Austin

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Texas Department of Transportation, Austin

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Texas Department of Transportation, Austin

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Federal Transit Administration, Washington, D.C.

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Federal Highway Administration, Washington, D.C.

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Texas Department of Transportation, Austin

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Federal Highway Administration, Washington, D.C.

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Federal Highway Administration, Office of Safety and Traffic Operations Research and Development, McLean, Va.