无人驾驶条件下共享停车匹配模型及算法

针对如何减少无人驾驶车辆在泊车过程中不必要的频繁移位和因此增高的事故风险,构建了在满足合理共享停车需求条件下最小化无人车移位成本的共享停车供需匹配优化模型,并利用解的结构特征设计了一种具有针对性的模拟退火求解算法.鉴于无人车灵活变换泊位的特征,将泊车需求与泊位供给在时间上加以分割,从而使得基于分割时段的匹配模型可以反映...     

Walking,cycling and the urban form: A Heckman selection model of active travel mode and distance by young adolescents

Physical inactivity of children and adolescents is a major public health challenge of the modern era but, when adequately promoted and nurtured, active travel offers immediate health benefits and forms future sustainable and healthy travel habits. This study explores jointly the choice and the extent of active travel of young adolescents while considering walking and cycling as distinct travel forms, controlling for objective urban form measures, and taking both a “street-buffer” looking at the immediate home surroundings and a “transport-zone” looking at wider neighborhoods. A Heckman selection model represents the distance covered while cycling (walking) given the mode choice being bicycle (walk) for a representative sample of 10–15 year-olds from the Capital Region of Denmark extracted from the Danish national travel survey. Results illustrate the necessity of different urban environments for walking and cycling, as the former relates to “street-buffer” urban form measures and the latter also to “transport-zone ” ones. Results also show that lessening the amount and the density of car traffic, diminishing the movement of heavy vehicles in local streets, reducing the conflict points with the density of intersections, and intervening on crash frequency and severity, would increase the probability and the amount of active travel by young adolescents. Last, results indicate that zones in rural areas and at a higher percentage of immigrants are likely to have lower probability and amount of active travel by young adolescents.     

乌江中上游双尾与隧道尾结合的机动驳船型

本文通过对隧道尾涡尾及隧道尾与双尾结合尾型等三种船型的船模快速性试验结果分析，得出隧道与双尾结合船型是浅水充机动驳适宜的船型，其单位功率负载率和海军系数较现有优秀隧道尾船型分别提高２８．６１％和３４．３１％。     

Learning from Los Angeles: transport,urban form,and air quality

Los Angeles is well known around the world as an automobile-oriented low density community, yet recent transportation policies have emphasized greater capital investment in rail transportation than in highways, and recent policies have attempted to discourage automobile usage through transportation demand management. While these policies have accomplished small shifts toward public transport and somewhat lower dependence upon singly occupied automobilies for work commuting, the financial costs of these policy changes has been very large in relation to their benefits. Proper pricing of transportation alternatives, more creative use of new and emerging transportation technologies, and the provision of many more opportunities for simpler private sector transport services, would all appear to be more promising as cost-effective approaches to coping with congestion in Los Angeles than the current regional transportation policies.     

The advantages of a high density,mixed land use,linear urban development

This paper describes the land use and transport characteristics of a strip of urban development located along the northern shore of Hong Kong Island. The strip of land, with an area of 22.5 sq. km, is 17 km long and has an average width of 1.3 km. It has a population of approximately one million and provides over 700,000 jobs. Despite its small size, it accommodates the CBD, residential districts, shopping complexes as well as most of the civic/institutional facilities that a city needs. Its urban form is linear not by design but by default – the topography of the area has constrained the development from spreading sideways. Surprisingly however, apart from economy in land utilization, it is considered to possess three other good qualities: high accessibility enjoyed by residents; few roads and commercially viable public transport. Its travel characteristics are analyzed, using results of a home interview survey conducted by the Government in 1992. In addition, various statistics published by the Government and public transport authorities are also used in the analysis.     

Fuzzy and adaptive fuzzy control for the automobiles' active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

高速双体船船型及降阻措施

本文根据三条不同船型高速双体船模型的试验结果，讨论了船型及片体间距对阻力的影响。同时，为了降阻目的，还进行了安装尾压浪板、消波水翼以及首压浪条等模型试验。试验结果表明：这些措施只要恰当地应用，将是有收效的。     

大型全集装箱船总体设计中有关问题的探讨

作者结合对3500 TEU集装箱船型技术论证对第三代以上大型集装箱船总体设计作了分析探讨,对设计中的箱型、平均箱重、船型,舱內列层数、稳性、航速、技术指标等主要问题发表了自己的见解,并提供了大型集装箱船的设计流程及计算公式供设计参考。     

用tent函数计算兴波阻力及优化船型问题

本文用理论方法计算了兴波阻力和改良船型的型值。理论计算可分下列两种情况: (1)对基本船型的水线迭加曲线薄船函数以计算其对应的改良船型。 (2)对基本船型的曲表面迭加曲面薄船函数以计算其对应的改良船型。 本文利用C.C.Hsiung提出的用tent函数方法计算兴波阻力。用SUMT混合罚因子优化技术计算改良船型的型值。 本文以y=(1-x~2)(1-z~4)数学船型和Series 60实用船型为基本船型,用tent函数方法对它们进行了兴波阻力计算,并且与其它兴波阻力计算方法进行了比较。本文还以上述两种船型为基本船型进行了改良船型的计算,并且得到了与它们相应的理论改良船型。     

浅吃水肥大型船的尾部线型研究

从分析船舶尾部伴流场对船舶阻力推进,操纵及船体振动性能等影响的观点,研究尾部三维伴流场,介绍尾型与伴流场之间关系及非对称双尾鳍船型的形成。非对称双尾鳍船型与优选的常规双尾鳍船型模型的阻力,自航及伴流场等比较试验结果表明,非对称双尾鳍船具有两大优点,首先,该船型能在浆前方产生一个与外旋浆旋向相反的预旋流,在保持了优良阻力性能前提下可提高外旋浆推进效率8％,获得阻力,推进,操纵各性能间的最佳配合,第二,轴向伴流分布比较均匀,满足BSRA5项衡准指标,改善了螺旋浆工作的流场条件,减少了螺旋浆产生空泡及其诱导船体激振的危险,使节能与减振得到统一,最后还介绍了该船型首制船“宁安1号”的实船测试结果及其由船模试验预报实船性能的一致性。