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排序方式: 共有233条查询结果,搜索用时 93 毫秒
71.
在分析研究集团电话计费管理系统的实时监控子系统中的数据采集与数据管理之间的接口问题的基础上发现常用的实现方法及其不足之处,随后提出直接将数据存入数据库和使用动态链接库的方法,并对它们的实现作了简要的介绍。 相似文献
72.
The past quarter of a century has brought with it significant change in the field of port management, both in terms of the goals that are set and the tools used. This trend has resulted in increased pressure on port authorities. The purpose of this paper is to deal in greater detail with developments in this area of port economics. 相似文献
73.
A. D. De Pater 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1982,11(3):121-141
Paper deals with the linear behaviour of a railway vehicle with any arbitrary number of wheelsets, body parts and connecting elements. A vehicle which has both perfect curving properties and asymptotical stability at vanishing speed, has to satisfy a twofold condition, indicated by Wickens in 1978. In the present paper this condition is derived in reliance upon the dimension theorem for linear mappings. How the investigation can be executed in practice, is shown for the case of a two-axled vehicle. At last the behaviour in a transition curve is discussed. 相似文献
74.
对桩周土弹性模量确定方法的探讨 总被引:5,自引:0,他引:5
综合分析了目前确定桩基础上弹性模量的3种方法:室内试验方法、基于过去工程实践的经验关系的方法及由单桩的荷载试验曲线反算的方法,提出了一种利用单桩荷载-沉降曲线确定土弹性模量的简单方法,并给出了计算公式和图表供工程实际应用。通过实例分析表明,弹性理论法计算桩基础沉降时,应该用单桩荷载试验曲线反算方法得到的土弹性模量作为计算参数。 相似文献
75.
Anouk de Brauwere Benjamin de Brye Sébastien Blaise Eric Deleersnijder 《Journal of Marine Systems》2011,84(3-4):85-95
Residence times and exposure times are computed for 13 boxes in the Scheldt Estuary, using the high-resolution tracer-transport model SLIM. The concepts are clearly defined and related to how they should be computed. First, the timescale values are compared with results published previously that were obtained with a simple box model, and an unexpected difference is revealed. This may suggest that a high-resolution model is necessary, even for the computation of such integrated quantities as residence or exposure times. Secondly, the newly computed residence times are compared to the exposures times to illustrate their intrinsic differences. From this difference, it is possible to propose a return coefficient, expressing the fraction of the exposure time that is due to “returning water”, i.e. water which has already left the estuary at least once. Finally, the estuarine exposure times are decomposed into the different box exposure times, resulting in a connectivity matrix. This matrix expresses how much time is spent in each of the estuarine subdomains during the water parcels' journey through the estuary. 相似文献
76.
Transportation - Assessing jobs-housing balance (JHB) and commuting efficiency is crucial to urban and transport planning. However, the scale dependency problem, meaning that metrics may be biased... 相似文献
77.
Transportation - Studies on the impact of changes in travel costs on car and public transport use are typically based on cross-sectional travel survey data or time series analysis and do not... 相似文献
78.
79.
Gustaaf De Monie 《Maritime Policy and Management》1995,22(3):235-238
Indian ports require substantial physical modernization, but their poor performance can also be attributed to administrative problems. Institutional change is both a necessary condition for privatization and one of its principal benefits. 相似文献
80.
J. Castillo A. P rez De La Blanca J. A. Cabrera A. Sim n 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(3):207-221
An optical tire contact pressure test bench developed by the IMMa group is described. The measurement system is based on the frustration of total internal reflection (FTIR) of light. The test bench allows performing normal pressure distribution and patch contact shape measurements on passenger car tires. The system is based on the use of a laterally illuminated glass on which the tire leans. Between them a plastic interphase is located that will cause the FTIR of light. A video camera catches the formed shining image through the glass. The brightness level in each pixel of the image can be related to the existing normal pressure. The study of the contact patch provided by the bench makes it possible to characterize tire behaviour under different loading states, inflation pressure, tire defects and toe and camber angles. The bench incorporates a computerized load and control system of the tire operation parameters, an image acquisition module and a data acquisition system that allow monitoring and acting on the experimental variables of interest in the tests such as load on the tire and environmental conditions. A supporting mechanical system incorporated to the bench allows providing the tire with variable toe and camber angles. From the images obtained with this system, the maximum normal pressure points, total force, size and shape of the patch can be determined, which are related to the tire-use conditions. As an application example, results that show the patch size and shape under different load and tire inflation pressures are presented. A further application, which is the use of the system for the detection and study of defective tires is also presented. 相似文献