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991.
A. Bonadero A. Elia The Research Office 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1984,13(6):339-356
A comparison between theoretical calculations on dynamic lateral behaviour of railway vehicles and experimental results shows quite a sizeable difference between the calculated critical speed and the actual speed at which side impact phenomena will repeatedly occur between wheel flange and rail (running speed limit), such impact speed being remarkably lower than calculated.
Another typical experimental aspect is that the running speed limit will considerably vary for the same vehicle depending on the test track conditions. Such difference is usually attributed to alterations of the wheel-rail contact surfaces, only.
This paper will discuss some concurrent causes which may prove far from negligible, such as the effects of track defects, an amplification of the dynamic lateral displacement between wheel and rail on approaching the critical speed, the track mechanical properties, and in particular the track lateral rigidity.
The influence of some geometrical factors typical of the wheel-rail contact, such as side clearance and linearized conicity, will also be discussed. The approach is based on the application of statistical methods to dynamic linear systems. 相似文献
Another typical experimental aspect is that the running speed limit will considerably vary for the same vehicle depending on the test track conditions. Such difference is usually attributed to alterations of the wheel-rail contact surfaces, only.
This paper will discuss some concurrent causes which may prove far from negligible, such as the effects of track defects, an amplification of the dynamic lateral displacement between wheel and rail on approaching the critical speed, the track mechanical properties, and in particular the track lateral rigidity.
The influence of some geometrical factors typical of the wheel-rail contact, such as side clearance and linearized conicity, will also be discussed. The approach is based on the application of statistical methods to dynamic linear systems. 相似文献
992.
S. A. Oleksowicz K. J. Burnham P. Barber B. Toth-Antal G. Waite G. Hardwick C. Harrington J. Chapman 《International Journal of Automotive Technology》2013,14(4):641-650
The use of a regenerative braking mode can reduce overall vehicle energy usage for most of the most common drive cycles. However, a number of technical issues restrict the use of regenerative braking for all possible braking situations. These issues are concerned with two key limitations. The first is related to physical limitations of the applied regenerative braking system, e.g. Electric Motor (E-Motor) power limits; energy storage device capacity and vehicle load transfer etc. The second limitation results from the potentially detrimental interaction between regenerative braking and the Anti-locking Braking System (ABS). The first type of limitation can, to some extent, be alleviated by suitable choice of hardware and, as a consequence, will not be discussed further in this paper. The second type of limitation concerns the regenerative braking strategies during an ABS event. Some of the regenerative braking strategies designed and investigated within the Low Carbon Vehicle Technology Project (LCVTP) will be described and analyzed in this paper. A comparison of competing strategies is made and conclusions are drawn together with suggestions for further research. The work has been progressed as a part of a major research programme; namely the LCVTP, which has been conducted within an extensive industrial and academic partnership, mutually funded by the European Regional Development Found and Advantage West Midlands. 相似文献
993.
Exploration of route choice behavior with advanced traveler information using neural network concepts 总被引:1,自引:0,他引:1
Hai Yang Ryuichi Kitamura Paul P. Jovanis Kenneth M. Vaughn Mohamed A. Abdel-Aty 《Transportation》1993,20(2):199-223
A model of driver's route choice behavior under advanced traveler information system (ATIS) is developed based on data collected from learning experiments using interactive computer simulation. The experiment subjected drivers to 32 simulated days in which they were to choose between the freeway or a side road. A neural network model is used as a convenient modeling technique in this initial phase of the analysis. The results indicated that most subjects made route choices based mainly on their recent experiences. It was also demonstrated that route choice behaviors are related to the personal characteristics as well as the characteristics of the respective routes. Travel experiences have less effect on the choice of the side road compared to the freeway and the results indicate that the prediction accuracy of the model, the acceptance rate of advice, and the quality of advice are closely correlated. The model developed here was for advice consistently provided at a level of 75 percent accuracy. The paper concludes with a discussion of experimental limitations and suggestions for future research. 相似文献
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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
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999.
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
1000.
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