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11.
Dirck Van Vliet 《Transportation Research Part B: Methodological》1981,15(1):65-68
An algorithm is proposed to calculate the matrix of trips which use a particular link in a road network or alternatively pass through a particular set of nodes given the route-splitting assumptions inherent in the Dial assignment algorithm. 相似文献
12.
Cline Laurent Paul Tett Teresa Fernandes Linda Gilpin Ken Jones 《Journal of Marine Systems》2006,61(3-4):149
Despite a tendency for the complexity of physical–biological models to increase, simple coupled models remain useful for some applications and can provide insights into crucial links between physical and biological processes. This argument is illustrated with an account of a simple 3-box model intended to help assess the capacity of fjords to assimilate nutrients from fish farms. The model, a dynamic version of the UK “Comprehensive Studies Task Team” (CSTT) steady-state model for eutrophication, was applied to Loch Creran (Scottish Western Highlands) and was implemented using Stella 8 and tested using historical data from 1975 (before the installation of a salmon farm) and field data collected in 2003, during the period of operation of the farm. The model's biological state variables are chlorophyll, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), and it includes a simple run-off model to convert rainfall into river discharge. The physical processes involved in exchange between the loch and the adjacent waters of the Firth of Lorne were parameterised as a constant daily exchange rate.Between 1975 and 2003, local inputs of nutrient increased but, despite this, there was little apparent increase in nutrient concentrations in the loch, and observed chlorophyll concentrations decreased substantially. Model simulations of chlorophyll and DIN agreed well with observations in 1975, as did DIN simulations in 2003. However, simulated chlorophyll was overestimated in 2003.Some of the agreement between observations and simulations come from the use of observed boundary conditions to force the model. However, even when boundary conditions are subtracted from simulations and observations, the simulations in most cases retain a significant correlation with observations, demonstrating that the model's ‘interior’ processes do add to its ability to replicate conditions in the loch. 相似文献
13.
阿尔斯通公司正计划与法国国营铁路(SNCF)合资开发1种摆式TGV列车,其摆式转向架样品(DTP)已完成线路试验,而其第二代产品DTP2也将在1999年7月开始进行线路试验。 相似文献
14.
Anton Th. Van Zanten Allan I. Krauter 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1978,7(4):203-231
This paper is concerned with the braking performance and the handling behavior of the tractor-semitrailer truck under optimal braking. Optimal control theory is used in order to deal with the problem and a combination of the steepest descent method and the Davidon Fletcher Powell method is used to solve it numerically. Results for some chosen braking maneuvers are obtained for a nonlinear truck model which has 14 degrees of freedom. These results show that, for the chosen maneuvers an idealized anti-skid braking is close to being optimal in the sense defined in this paper. Implementation of an idealized anti-skid braking on the tractor-semitrailer truck, however, may be not desirable. 相似文献
15.
This paper discusses the question about how to write a literature review paper (LRP). It stresses the primary importance of adding value, rather than only providing an overview, and it then discusses some of the reasons for (or not) actually writing an LRP, including issues relating to the nature and scope of the paper. It also presents different types of LRPs, advises on reporting the methodology used for the selection of papers for review, and the structure of an LRP. An important conclusion is that the heterogeneity in LRPs is very large. This paper also presents some of the aspects that the authors feel are important structural and contextual considerations that help produce high-quality review papers. 相似文献
16.
K. T. R. Van Ende D. Schaare J. Kaste F. Küçükay R. Henze F. K. Kallmeyer 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(10):1362-1383
For steer-by-wire systems, the steering feedback must be generated artificially due to the system characteristics. Classical control concepts require operating-point driven optimisations as well as increased calibration efforts in order to adequately simulate the steering torque in all driving states. Artificial neural networks (ANNs) are an innovative control concept; they are capable of learning arbitrary non-linear correlations without complex knowledge of physical dependencies. The present study investigates the suitability of neural networks for approximating unknown steering torques. To ensure robust processing of arbitrary data, network training with a sufficient volume of training data is required, that represents the relation between the input and target values in a wide range. The data were recorded in the course of various test drives. In this research, a variety of network topologies were trained, analysed and evaluated. Though the fundamental suitability of ANNs for the present control task was demonstrated. 相似文献
17.
Laurent Van Malderen Bart Jourquin Isabelle Thomas Thomas Vanoutrive Ann Verhetsel Frank Witlox 张宇译 《城市交通》2012,(4):79-90
公司是通勤交通的主要创造者,在与交通相关的讨论中,公司扮演着重要角色。近几年,公司提出了多种政策措施,以改善员工的出行条件,但其愿景与行动通常被研究文献所忽视。为了讨论比利时公司在交通政策方面的最佳实践,分析了现有研究成果和比利时的两次大规模通勤交通调查。首先,对公司进行分类,以便确定在推广替代交通方式方面受员工欢迎的公司。然后,通过量化分析确定交通政策的最佳实践。结果显示,最佳替代交通方式取决于公司特征;自行车交通最适合小型工作场所,大型工作场所和位于建筑密集区或市中心的公司则更适合推广公共交通;在公司交通管理中,财务激励、设施提供、信息传播和停车管理均起重要作用。 相似文献
18.
ABSTRACTPort activity plays an important role in facilitating international trade. Sufficient capacity is indispensable for a port to attract flows to a region and retain them. The capacity decision is the result of a trade-off between investment and waiting costs. Traditional methods to value expansion projects do not deal adequately with managerial flexibility in the face of uncertainty from different sources in the complex port environment. In this paper, real options (RO) models are identified as an alternative method to making project valuations and investment decisions, as they attribute the correct value to managerial flexibility under uncertainty. In order to be able to build and use such RO models for port capacity investment decisions, the sources and implications of uncertainty in the port and the different RO model specifications need to be understood. To this end, both the literature about uncertainty in the port context and the literature about real options models are reviewed in order to provide researchers who want to build their own decision-making models, with the necessary knowledge of both fields. The review makes clear that the complex interactions in and competition between the logistics chains and their actors coming together in ports have significant impacts on port capacity. Uncertainty is also caused by uncertain international trade flows and changes in legislation following new technologies and environmental impacts. An analysis of the components of some general RO models shows how the options of flexible output, investment size and timing are valued by RO models in a setting with demand uncertainty. Moreover, the review presents researchers with insights in how to deal with cooperative and competitive interactions in the chain, time to build, cyclical markets and legislation changes. It also shows how to value the expansion and the phased investment options. The new insights resulting from this review are subsequently combined in a framework that serves as a guideline to build RO models for port capacity investments. Finally, an exemplifying application of the framework is used to build an actual port capacity investment decision model. 相似文献
19.
Historic vehicles (HVs) are the heritage of road transport that have surprisingly received little attention in the academic literature. This study presents an overview of the literature on HVs, focusing on the three topics that dominate the policy debate on transport: environmental, safety and congestion impacts. We observed that polluting emissions of HVs are per kilometre much higher (often a factor 5 or more) than those of moderns vehicles. The annual average mileage per vehicle per year of HVs is much lower than other vehicles. The lower active and passive safety levels of HVs are compensated by the way these vehicles are driven, resulting in the risk factors per kilometre being roughly equal or lower than other vehicles. The contribution of HVs to congestion is negligible. However, the transport policy discourse is divided on the topic of HVs. More comprehensive and effective laws and regulation are needed to protect this aspect of the heritage of road transport whilst concurrently avoiding or limiting the problems caused by them. 相似文献
20.