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排序方式: 共有166条查询结果,搜索用时 15 毫秒
51.
Daniel Lindvai-Soos Martin Horn 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(7):1002-1027
In this article a novel vehicle dynamics control concept is designed for a vehicle equipped with wheel individual electric traction machines, electronically controlled brakes and semi-active suspensions. The suspension's cross-couplings between traction forces and vertical forces via anti-dive and anti-squat geometry is utilised in the control concept to improve driving comfort and driving stability. The control concept is divided into one main and two cascaded branches. The main controller consists of a multivariable vehicle dynamics controller and a control allocation scheme to improve the vehicle's driving comfort. The cascaded feedback loops maintain the vehicle's stability according to wheel slip and vehicle sideslip. The performance of the combined vehicle dynamics controller is compared to a standard approach in simulation. It can be stated that the controller piloting semi-active suspensions together with brake and traction devices enables a superior performance regarding comfort and stability. 相似文献
52.
John R. Siddorn J. Icarus Allen Jerry C. Blackford Francis J. Gilbert Jason T. Holt Martin W. Holt Jeff P. Osborne Roger Proctor David K. Mills 《Journal of Marine Systems》2007,65(1-4):417
This paper outlines an approach to complex spatio-temporal marine ecosystem modelling as applied to the North Western European Continental Shelf. The model presented here combines an eddy-permitting (approximately 6 km horizontal resolution) baroclinic model, the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS), with the European Regional Seas Ecosystem Model (ERSEM). This has been run within an operational framework using operationally available high resolution atmospheric and lateral boundary forcing, allowing hindcast and near-real time nowcast simulations to be performed. The modelled surface temperature and chlorophyll distributions are presented, and interannual variations discussed. Validation of both the physical and ecosystem submodels show the system to be effective, whilst highlighting areas where improvements in the system can be made. Distinct regional differences in predictive skill are shown. The system presented is ready for operational implementation to provide products and services for use both scientifically and in coastal zone and shelf seas management activities. A programme of work to update the system is already in place. 相似文献
53.
Crime on public transit is receiving increasing attention in the United States. This paper reviews security precautions taken in the planning of bus operations. Also included is a statistical analysis of criminal incidents occurring over a ten-year period on the Southern California Rapid Transit District of Los Angeles. The analysis shows that crime on transit has increased about in proportion to transit ridership, and that it is concentrated in both space and time. Crimes occur mostly on routes which traverse areas having high crime rates in general. Although most transit crimes occur at hours when ridership is high, the rates of occurrence are disproportionately high during the evening hours. Bus drivers experience much higher rates of exposure to criminal incidents than transit passengers. The transportation environment is really a complex of many dissimilar environments, and a variety of strategies is required to meet the needs posed by diverse environments. 相似文献
54.
实现化、实例化和个性化——系统功能语言学的三种层次关系 总被引:1,自引:0,他引:1
系统功能语言学已走过50多年的历程。50多年里,首先研究的主要是语言系统层次的实现化关系,后来研究与之互补的实例化关系。语言系统中包括音系字系系统、词汇语法系统和语篇语义系统。这三个系统层次是实现关系,语篇语义由词汇语法实现,词汇语法由音系字系实现。每个系统都受语域和语类的影响,从而产生不同的文本类型,文本就是语域和语类的实例化结果。但实现化和实例化对个体文本中意识形态和互文性的解读缺乏说服力,急需建构与它们互补的其他层次关系。本文是在介绍实现化和实例化的基础上推出个性化层次关系,从而丰富系统功能语言学对大语篇研究的理论框架。除了介绍三种层次关系外,还通过实例分析来验证三种互补层次关系的可用性。 相似文献
55.
Abstract The negative impacts of transport are in general associated with costs. These costs are usually denoted as ‘external costs’ or ‘externalities’. This paper presents a tool for calculating external costs for freight transport together with its application to a number of case studies. The categories considered include: air pollution, greenhouse gases, noise, accidents and congestion. Results are presented for a number of different transport alternatives as total costs and divided into categories. The uncertainties in the results are discussed. The assessment of these costs is essential for predicting future transport costs. 相似文献
56.
Abstract Despite considerable examination of the impact of telecommunications on travel, little empirical evidence sheds light on the impact of e‐shopping on travel—a recent and increasingly popular form of telecommunications. This paper analyses determinants of online buying and their relationship with in‐store shopping, using empirical data obtained from Minneapolis, USA, and Utrecht, the Netherlands. Based on chi‐square tests and logistic and ordinary least‐squares regressions, the results indicate that online buying is affected by sociodemographics and spatial characteristics of people, their Internet experience, and their attitudes towards in‐store shopping. US respondents who prefer to see products in person are less likely to buy online. Dutch respondents are more likely to buy online as travel times to shops are shorter. At first sight, this counterintuitive result might be related to an urban, innovative lifestyle that supports e‐shopping. A more detailed analysis of Dutch online buyers reveals that they make more shopping trips than non‐online buyers and have a shorter shopping duration. The results indicate that the relationship between online buying and in‐store shopping is not one of substitution but of complementarity. 相似文献
57.
1简介
在汽车制造过程中,作为一种金属连接的方式,结构粘合剂的应用正处于迅猛发展阶段。结构粘合剂可增强粘接结构的刚性、耐久性和抗冲撞性。此外.该粘合剂的使用使得相容性差的金属之间的粘接变得容易,因此从成本高低和车体质量大小方面加大了车体结构优化设计的可能性。 相似文献
58.
59.
Antonio Páez Martin Trépanier Catherine Morency 《Transportation Research Part A: Policy and Practice》2011,45(7):640-652
Smart card automated fare payment systems are being adopted by transit agencies around the world. The data-storage characteristics of smart cards present novel opportunities to enhance transit services. On the one hand, there are fare policies, where smart card holders are given specific rebates on the use of the service based on usage patterns or levels. On the other, there are non-fare policies, for instance if holders receive advantages, such as rebates and offers, from commercial partners. The purpose of this paper is to present a geodemographic framework to identify potential commercial partnerships that could exploit the characteristics of smart cards. The framework is demonstrated using data from Montreal, Canada. Household survey data, specifically trip ends, and business data points are jointly used to determine the exposure of various types of establishments to users of the Montreal Metro network. Spatial analysis of business establishments in the neighborhood of metro stations helps to identify potential commercial partners. The results illustrate the potential of geodemographic analysis to generate intelligence of commercial interest. 相似文献
60.