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51.
Russell Atkins 《汽车杂志》2008,(7)
是继续奋战还是选择明年底退役这是最近困扰莱科宁的一个棘手的问题,因为在加拿大的围场里大家都在讨论莱科宁可能会真的选择在2010年后恢复自己自由的身份,也就是离开这个他视为职业所在的F1赛场. 相似文献
52.
A. G. Thompson B. R. Davis 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2001,35(3):217-222
The inner loop control for the actuator force can be quite simply compensated by means of a correction term to the desired force signal at the input. The correction requires only a measurement of the actuator piston velocity and is employed to cancel the loop disturbance caused by the oil flow to the actuator. Although an additional time constant is introduced by the integration in the inner loop force control, the overall performance is nevertheless quite close to that of an ideal optimal system. 相似文献
53.
A. G. Thompson B. R. Davis 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,34(2):143-150
Expressions are derived for the numerical computation of rms values for control force, suspension stroke and dynamic tyre deflection in a quarter-car vehicle model on a random road of given roughness. A quadratic performance index is employed and the effects of the assumed weighting factors on the rms values and overall static stiffness determined. 相似文献
54.
Public transport in Britain has traditionally operated under conditions of regulation. The 1930 Road Traffic Act imposed controls upon the quantity and quality of transport regulations, with an abolition of the quantity controls associated with inter‐city coach services. The principal objectives of the Act were to eliminate restriction upon entry to the market and to promote competition between coach operators. This paper is based on research which was undertaken to establish the impact of the 1980 Transport Act upon express (inter‐city) coach services in Britain. The effects of the legislation are examined in relation to the experience of various coach operators, British Rail, and the inter‐city traveller. This provides evidence of the way in which the supply of, and demand for, public transport behaves in a competitive, deregulated environment. It is shown that at least in net terms, the consumer has enjoyed short‐term benefits. Greater uncertainty surrounds the long‐term situation. The main competition has been confined to the principal trunk routes and has taken place between the state‐owned undertaking of National Express and British Rail. The outcome of deregulation for the private sector has been disappointing. The paper identified similarities which exist between inter‐city and local public transport services. In this context, the lessons derived from express deregulation are employed to suggest likely developments in the deregulation of stage carriage (local) services in Britain. 相似文献
55.
Robert A. Swett Charles Sidman Timothy Fik Russell Watkins Paul Ouellette 《Coastal management》2013,41(6):613-627
Growth in the number of recreational vessels that use inland and coastal waterways, coupled with the diversity of boating activities, results in increased boating-related conflicts, accidents, and fatalities. This situation has led to numerous requests from boaters, shorefront property owners, waterfront businesses, and local governments for the imposition and enforcement of boating safety speed zones within Florida's Intracoastal Waterways. A decision-support framework that incorporates Geographic Information Systems (GIS)–based risk assessment was developed to assist the Florida Fish and Wildlife Conservation Commission's Division of Law Enforcement evaluate requests and applications for the establishment of boating safety zones, pursuant to the Florida Administrative Code Rule 68-D-23.105 “Criteria for Approval of Regulatory Markers.” The risk assessment uses geospatial data compiled from multiple government agencies, survey data from subject matter experts, and public input from participatory workshops. Relevant spatial data includes waterway features and marine infrastructure from field surveys, vessel traffic patterns observed and mapped from aerial reconnaissance, and indicators of boater behaviors extracted from accident and citation reports. The outcome is a characterization of waterway segments according to perceived risk to boating safety. The application was tested in two Florida counties and it helped guide the establishment of new, and the revision of existing, boating regulatory zones within their Intracoastal Waterways. The application design is such that it is adaptable to waterways beyond those in Florida. 相似文献
56.
Jennifer A. Pazour Russell D. Meller Letitia M. Pohl 《Transportation Research Part A: Policy and Practice》2010,44(3):119-135
High-speed rail is often touted as a means to reduce congestion on the United States’ highways by removing passenger car traffic. But highway congestion can also be reduced by reducing the amount of freight traffic. So, given the advances in high-speed rail, the potential exists for developing a national high-speed network for freight distribution. To design such a network considering highway traffic and transit times, we present an uncapacitated network design model with a post-processing step for the capacity constraint. To illustrate how our modeling approach could be used by policy makers to evaluate the impacts of a high-speed rail network, we apply our models with preliminary data on high-speed rail operating parameters for freight applications and from current data on shipments from a major truckload carrier and the US Census Bureau. 相似文献
57.
Gregory L. Thompson 《Transportation Research Part A: Policy and Practice》1996,30(6):469-471
58.
A.G. Thompson B.R. Davis 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1990,19(3):131-149
In pantographs used for current collection on high speed electric trains it is desirable to minimise the fluctuations in the contact force between the collector head and the catenary. A simple two-mass linear model is employed for the pantograph and the design of the proposed control system is based on the input admittance at low frequencies. Frequency shaping is incorporated in the performance index, and a simple dynamic controller is employed to achieve optimality in an equivalent transformed system, while minimising the number of feedback quantities to be measured. A significant reduction in the average contact force appears possible. 相似文献
59.
60.
A. G. Thompson Visiting Senior Research Fellow 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1977,6(1):37-40
The yaw rate response for a two-degree-of-freedom car model requires a family of curves for different degrees of oversteer or understeer. By use of non-dimensional co-ordinates this family is reduced to one single curve. The ordinate ρ is the ratio of yaw rate response to that of a neutral steering car at the same speed and is less than 1 for understeer and greater than 1 for oversteer. Since ρ is also the ratio of the side-slip angle response it is hence, a unique measure of the steady-state steering characteristics. 相似文献