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电力是现今大部份铁道系统的动力来源. 可靠、有效率及安全的电力输送对整体铁道服务质素尤为重要,跟其它大型工程系统一样,铁道供电系统的设计,运作及筹划相当倚重计算机仿真.本文将回顾铁道供电系统仿真的模型及一般常规,并通过模拟结果例子及实际应用,介绍最新的模拟方式发展.本文亦对铁道供电系统仿真的未来挑战作出评论. 相似文献
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Increase in particle number emissions from motor vehicles due to interruption of steady traffic flow
E.R. Jayaratne L. Wang D. Heuff L. Morawska L. Ferreira 《Transportation Research Part D: Transport and Environment》2009,14(7):521-526
We assess the increase in particle number emissions from motor vehicles driving at steady speed when forced to stop and accelerate from rest. Considering the example of a signalized pedestrian crossing on a two-way single-lane urban road, we use a complex line source method to calculate the total emissions produced by a specific number and mix of light petrol cars and diesel passenger buses and show that the total emissions during a red light is significantly higher than during the time when the light remains green. Replacing two cars with one bus increased the emissions by over an order of magnitude. 相似文献
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The demand for rail freight transportation is a continuously changing process over space and time and is affected by many quantitative and qualitative factors. In order to develop a more rational transport planning process to be followed by railway organizations, there is a need to accurately forecast freight demand under a dynamic and uncertain environment. In conventional linear regression analysis, the deviations between the observed and the estimated values are supposed to be due to observation errors. In this paper, taking a different perspective, these deviations are regarded as the fuzziness of the system's structure. The details of fuzzy linear regression method are put forward and discussed in the paper. Based on an analyzes of the characteristics of the rail transportation problem, the proposed model was successfully applied to a real example from China. The results of that application are also presented here. 相似文献
24.
Ana M. Nobre Suzanne B. Bricker João G. Ferreira Xiaojun Yan Martin De Wit João P. Nunes 《Coastal management》2013,41(5):536-555
This article presents an approach that couples coastal ecosystem modeling with integrated environmental assessment methodologies to support coastal management. The focus is to support the development of an ecosystem approach to aquaculture management including interactions with watershed substance loading. A Chinese bay, with intense aquaculture and multiple catchment uses, and where significant modeling efforts were undertaken is used as a case study. The ecosystem model developed for this bay is used to run scenarios that test the local management strategy for nutrient reduction. The corresponding ecological and economic impacts of the managers’ scenarios are analyzed by means of the Differential Drivers-Pressure-State-Impact-Response (ΔDPSIR) analysis. Emphasis is given to the analysis of the eutrophication process in the bay including present eutrophic condition and the expected changes due to the simulated scenarios. For this purpose, the Assessment of Estuarine Trophic Status (ASSETS) screening model is a valuable tool to interpret and classify the data and model outputs regarding eutrophication condition and to evaluate the manageable level of the nutrient loading entering in the bay. 相似文献
25.
Abstract This article investigates the role of bus rapid transit as a tool for mitigation of transport‐related carbon dioxide (CO2) emissions. We analyse a Quality Bus Corridor (QBC) implemented in Dublin, Ireland, in 1999 and estimate CO2 emissions associated with differing levels of bus priority for the period 1998–2003 and for the Kyoto commitment period (2008–12). Associated monetary values are established using CO2 prices from the European Union Emissions Trading Scheme. We find that, in the absence of a QBC, peak‐time emissions for our sample population would have been 50% higher than in the factual scenario. For the Kyoto commitment period, we find the median value of the policy implementation to be in the region of [euro]650 000. 相似文献