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971.
Preview Estimation and Control for (Semi-) Active Suspensions 总被引:3,自引:0,他引:3
R.G.M. Huisman F.E. Veldpaus J.G.A.M. Van Heck J.J. Kok 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1993,22(5):335-346
An active suspension with preview is tested for rounded pulses and a stochastic road surface, and is compared to a passive suspension. The spectacular performance improvement obtained for a step function as road surface is not achieved but the improvement is still significant. The frequency response of the active suspension is determined for comparison with some suspension systems found in literature
An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently. 相似文献
An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently. 相似文献
972.
Michael A. Titz 《Maritime Policy and Management》1989,16(3):189-211
This work analyses whether port state control (PSC) has been effective in reducing environmental pollution in the region it covers. The analysis covers the technical and political aspects of PSC's effectiveness. To match the complexity of marine environmental pollution and safety issues, several indicators are developed to assess performance under both aspects. Previous studies on quantitative and qualitative material, as well as fresh evidence, are utilized to obtain quantitative or qualitative evaluations, as the case may be. The separate insights are then combined to reach an integrated conclusion. PSC is found to be effective in fighting marine environmental pollution, but with peripheral shortcomings of a mainly operational nature. These shortcomings limit the effectiveness to a less than optimal degree. 相似文献
973.
FAST对10亿t总吨位的大轴重测试 总被引:2,自引:0,他引:2
美国联邦铁路管理局(FRA)的提速运营测度研究室(FAST),对重为143000kg,35.4t的大轴重车辆进行了测试,至今测试的总吨位已累计超过了10亿t,试验分5个不同的测试阶段,计划为开行大轴重车辆的安全性和经济性提供信息。 相似文献
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977.
This paper intends to demonstrate that the performance indicator analysis technique can be successfully used as a diagnostic tool to identify operational inefficiency and ineffectiveness at the route level of transit operation. The technique has been applied on 14 bus routes of Bangkok Mass Transit Authority to reveal the inter-route differences in operational efficiency and effectiveness. Twenty performance indicators relating to costs of services, fuel consumption, staff ratio, crew productivity, fleet utilization, service output per bus, daily revenues, etc., were selected to represent the resource efficiency, resource effectiveness and service effectiveness of the bus system. Results of the analyses revealed that considerable variations existed across the routes against many of these 20 selected indicators. These included variations in terms of labor and capacity utilization, maintenance expenditure, etc., many of which can be improved through suitable managerial measures. Based on these findings, specific recommendations have been made for improvement in the deficient areas that are considered to be within the operator domain. These indicators also provide a basis for comparison over time, with other operators and standards. A ranking scale was also developed to determine the over all attractiveness of the routes. 相似文献
978.
A. H. Vanags 《Maritime Policy and Management》1993,20(4):319-324
Conventional wisdom has it that, because of locational and other advantages, transit trade and transport, especially maritime transport, could be expected to play a major role in the development process of the Baltic States which was expected to follow their renewed independence in 1991. This paper secks to evaluate this proposition. The first section of the paper provides a brief account of the present state of the shipping and port sectors in the three Baltic republics and offers some speculation about likely future developments. The following section considers whether there is any historical basis for the presumption in favour of transit trade. The paper concludes with a somewhat speculative discussion of whether the Baltic States might be expected to possess any long run comparative advantage in maritime transport. It is suggested that in this respect a distinction should be made between ports and shipping and that in a more prosperous future, shipping, in particular, might be expected to decline in importance. 相似文献
979.
This paper summarises work done to assess the market potential and likely financial performance of a planned high-speed rail link connecting Sydney, Canberra and Melbourne, under a variety of scenarios concerning the services offered and the possible market responses of the competing transport modes in the corridor. In the Australian context, such a link has the characteristics of an essentially new transport mode since existing rail services are extremely poorly developed. The expectation was that generated demand could be a substantial part of the overall ridership. A programme of market research was commissioned by the private consortium considering the project, designed to support forecasting models capable of predicting both diverted and generated travel on the new service. A major survey of current travellers was conducted in 1988, followed by an extensive collection of stated preference evidence about the factors affecting the travel decisions of both existing travellers and those who had not recently made any journeys in the corridor. The paper focuses mainly on the design and organisation of the surveys, on the analysis approach, and on the methods used to generate forecasts for simulated populations and scenarios. 相似文献
980.
A. Graillot 《Maritime Policy and Management》1986,13(2):155-164
There is much contraversy regarding this issue. On the one hand there are the 'islanders' Which are generally the countries of Anglo-Saxon culture or influence in Which ports are often considered as mere commercial enterprises, and on the other hand the continentals where ports are instruments of national or local policy. The French belong by tradition to the latter. But a further examination of the subject would be useful; this article presents this reappraisal.
I would like first of all to examine what lies behind the notion of government subsidy for ports, and then to draw conclusions regarding 20 years of French law which have steadily reformed the status of French Ports. 相似文献
I would like first of all to examine what lies behind the notion of government subsidy for ports, and then to draw conclusions regarding 20 years of French law which have steadily reformed the status of French Ports. 相似文献