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11.
Langmyhr  Tore 《Transportation》2001,28(2):157-178
Investment packages, involving several modes, emerge as a widely used element in urban transport policies. Package policies entail some specific possibilities and traps in the planning and decision-making processes. To assess these properties, the concepts of instrumental and communicative rationality are applied. These rationality concepts serve to structure the pro and con arguments concerning four crucial considerations in package planning: The use of formal impact assessment methods, the overall size and changeability of the investment packages, the share of road vs green modes investments, and the sequence of implementation. These issues are investigated by drawing on experience from transport investment packages in six Norwegian cities.  相似文献   
12.
Vehicle-Bridge Interaction   总被引:4,自引:0,他引:4  
With the emergence of high-speed trains, dynamic loads on bridges have changed. A method for estimation of the time-dependent vehicle-bridge interaction forces has been developed in the present paper. The increase (or decrease) of the bridge response due to dynamic effects is determined.

The moving constant-force problem is reviewed in some detail. Results obtained by the present method for the moving-mass problem are compared with existing experimental and theoretical results as reported in the literature. A parametric study of bridge responses is made. The parameters varied are the vehicle speed, the ratio of vehicle mass to bridge mass, the ratio of vehicle eigenfrequency to bridge eigenfrequency, and the relative damping of the vehicle. Finally, the influence of an initial bridge deflection is discussed.  相似文献   
13.
A 5-DOF plane vehicle model is studied. A randomly profiled road is assumed to impart normally distributed stationary vertical random displacements to the front and rear wheels. Several vehicle performance criteria based on response mean square spectral densities are discussed. It is emphasized that these performance criteria contain more information than do the simple response standard deviations. A computer program has been developed for optimization of two or more of the system parameters to make a vehicle response (or a weighted sum of responses) a minimum. Constraints on parameters and responses can be introduced. Ride comfort, road holding, energy absorption, fatigue failure and first-passage failure are studied. Numerical examples are given.  相似文献   
14.
Despite the many socio-economic similarities between Sweden and Norway, differences in jurisdiction, organisation, cooperation, and financing of long-distance passenger train and coach services have led to the development of four distinctively different ways of serving the markets. This paper describes how the train and coach markets have developed in the two countries, with emphasis on regulatory and industrial structure and a couple of performance variables.Looking at passenger rail, both countries separated infrastructure from operation over a decade ago. However, while Norwegian rail is characterised by an almost monopoly supplier, rail services in Sweden are partly decentralised to the responsibility of county authorities and are widely subjected to competitive tendering. The rest of the network is about to be opened up for on-the-track competition. Swedish Rail (SJ) has spent the last decades consolidating its core business (passenger rail) and sold out its other businesses. In contrast, the Norwegian state rail (NSB) has expanded its business to become a major bus operator and property owner, with extensions also into the Swedish market.The coach industry was more recently deregulated in both countries. The Swedish coach market is dominated by privately owned companies operating services to and from Stockholm. In Norway, state-owned NSB is a major coach operator on medium distance routes, and is also the largest partner of Nor-Way Bussekspress which totally dominates long-distance coach services. Further, the Norwegian coach market is characterised by cross-ownership and cooperation which has enabled an extensive route network which covers most of Norway.We find distinct differences in achievements in the two modes and in the two countries. Swedish rail services have succeeded in winning market shares and in renewing and developing both infrastructure and service levels to a greater extent than the Norwegian model. On the other hand, the Norwegian coach market seems to be more developed and efficient compared to its Swedish counterpart.The paper concludes with a discussion on the possible links between the different approaches and the performance observed, with the aim to stimulate further and more detailed research on some important issues.  相似文献   
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