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991.
Michael G H Bell 《先进运输杂志》2002,36(3):231-242
In‐vehicle information has an important social role to play in improving the efficiency and safety of travel by all modes. In this review, three generations of system are identified. The first generation consists of simple in‐vehicle units relying heavily on external data. The second generation has more sophisticated in‐vehicle units with colour TFT screens and DVD players for maps and entertainment. The third generation again makes use of external data, using the mobile phone network to download map sections and other data as and when required, thereby obviating the need for beacons and map CDs. For locationing, GPS (and/or Galileo, the European version of GPS) remains the favoured technology. Portable devices offering multi‐modal information could improve inter‐modal transport efficiency. 相似文献
992.
C. G. Daley 《Marine Structures》2002,15(6):1-559
A new International Association of Classification Societies standard for polar ship design, in the form of a unified requirement is being developed by an international committee with representatives from many classification societies and with the active participation of many polar nations. The framing structural requirements have been developed by a combination of analysis of existing rules and ships, finite element (FE) analysis and analytical solutions of plastic collapse mechanisms. This paper describes the derivation of the 3-hinge and asymmetrical shear plastic collapse mechanisms using work–energy principles. Energy methods are robust and well suited for developing design standards. The results are shown to compare well with non-linear FE analyses of frame strength. 相似文献
993.
994.
介绍了西班牙Talgo 350动车组设计原则、车体倾摆系统、牵引和制动以及内部装备的新技术。 相似文献
995.
Direct Computation of the Performance Index for an Optimally Controlled Active Suspension with Preview Applied to a Half-Car Model 总被引:1,自引:0,他引:1
A. G. Thompson C. E. M. Pearce 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2001,35(2):121-137
A quadratic integral performance index is defined for a linear active preview-type suspension and a series of matrix expressions derived for its evaluation by means of MATLAB or some similar computer program in the case of a unit step input to the system. The computation, which is both fast and accurate compared to simulation, requires the solution of Lyapunov- and Riccati-type equations. Some examples of numerical computation are given and these show excellent agreement with published results. The conclusion features a useful computer program. 相似文献
996.
P. Pondaven C. Fravalo D. Ruiz-Pino P. Trguer B. Quguiner C. Jeandel 《Journal of Marine Systems》1998,17(1-4)
A coupled 1D physical–biogeochemical model has been built to simulate the cycles of silicon and of nitrogen in the Indian sector of the Permanently Open Ocean Zone of the Southern Ocean. Based on a simplified trophic network, that includes two size classes of phytoplankton and of zooplankton, and a microbial loop, it has been calibrated by reference to surface physical, chemical and biological data sets collected at the KERFIX time-series station (50°40′S–68°25′E). The model correctly reproduces the high nutrient low chlorophyll features typical of the studied area. In a region where the spring–summer mixed layer depth is usually deeper than 60 m, the maximum of chlorophyll never exceeds 1.5 mg m−3, and the annual primary production is only 68 g C m−2 year−1. In the surface layer nitrate is never exhausted (range 27–23.5 mmoles m−3) while silicic acid shows strong seasonal variations (range 5–20 mmoles m−3). On an annual basis 71% of the primary production sustained by nanophytoplankton is grazed by microzooplankton. Compared to North Atlantic, siliceous microphytoplankton is mainly prevented from blooming because of an unfavourable spring–summer light-mixing regime. Silicic acid limitation (high half saturation constant for Si uptake: 8 mmoles m−3) also plays a major role on diatom growth. Mesozooplankton grazing pressure excerpts its influence especially in late spring. The model illustrates the efficiency of the silica pump in the Southern Ocean: up to 63% of the biogenic silica that has been synthetized in the photic layer is exported towards the deep ocean, while only 11% of the particulate organic nitrogen escapes recycling in the surface layer. 相似文献
997.
D. V. Lyridis T. Fyrvik G. N. Kapetanis N. Ventikos P. Anaxagorou E. Uthaug H. N. Psaraftis 《Maritime Policy and Management》2005,32(4):403-420
In order to identify the elements constituting quality in services, a business process modelling methodology has been applied in the case of a Greek liner shipping company. The company operations have been identified and analysed in order to assess the complete performance of service elements and thereafter identify how to match the service performance against the user requirements. A liner container service within Europe has to compete with the road transport which, in many cases, is an alternative to the sea transportation and not complementary to it. Thus, not only the ship has to be envisaged when aiming to improve quality in services but also the whole chain, namely port authorities, land transportation enterprises, subcontractors, agents, charterers and others. A set of potential improvements within this framework are thus suggested and time and cost (examined in a specific voyage scenario) are measured before and after the implementation of these measures. Very large time and cost savings are observed after the application of the technology improvements, allowing, in fact, the shipping company to even increase the number of round trips per year in the examined route. This indicates that very large benefits can be drawn by analysing and critically adjusting business processes in modern shipping companies. 相似文献
998.
2 车辆制动能力2.1 单容积系统 与欧洲实际情况显著不同的是,北美大多数车是称作“单容积”型式。这意味着不管车辆的空与重,制动力是不变的。为设计目的所使用的一个工业标准(AAR Sec.E)提出了“制动率”概念,将制动力除车辆净重,在标准状态下导出空车和重车制动率。众所周知的净制动率可以认为系统中的摩擦和其他损失不计,使用高摩闸瓦,重车制动率约为7%~10%、空车制动率为30%。由于最新的车辆自重和总载重之间有较大的差别,设计一种可以在载重状态下提供合适制动力,同时可以避免空车时制动力过剩导致车轮问题的制动系统变得越来越困难。 2.2 变容积系统——空/重车调整装置 已经研制出多种“空车/重车”调整装置,绝大多数调整装置通过S1或相似的载荷传感阀,来比较车体相对于转向架侧架的高度,并应用于通过P1或相似的载荷比例阀,在制动缸内产生大小合适的压力。后来出现的系统Ellcon-National 6600-I、NYAB EL-60和WABCO ELX-B将传感和比例阀集中在同一装置中。相似的系统如Ellcon-National 6600-IU(图16)和WABCO ELX-U,将容积风缸包含在组合单元内。图17为典型的ELX型空/重车制动装置。 相似文献
999.
IntroductionIn the past twenty years,many Chinese lan-guage processing systems have been developed.Excellent researchers[1~ 3] have led Chinese lan-guage processing into a new era.However,seg-mentation ambiguity problem has not beensolved satisfyingly.The current techniques to eliminate segmenta-tion ambiguity can be classified into two cate-gories:rule- based techniques( strong technique)and statistic- based techniques( soft technique) .Hybrid techniques belong to both.In rule- based techn… 相似文献
1000.