杭州市公共自行车系统规划

为解决“公交最后一公里”的问题,缓解城市“行路难、停车难”的状况,建设可持续发展的绿色交通系统,对杭州市公共白行车进行规划。通过分析杭州市公共自行车首批服务点存在的问题,结合实际情况与相关规划,提出了公共自行车的发展目标,应具备的特征、系统构架及规模。最后,提出服务点的布点原则和配车规模,并给出固定服务点近期布局规划方案。     

武汉市公共自行车租赁点布局规划

结合武汉市公共自行车租赁点布局规划,探索公共自行车租赁点布局规划理论,提出“总量控制,分类分块,平衡规模,灵活调整”的总体布局思路。将租赁点划分为公交点、公建点、居住点、游憩点和校园点5类,探讨居住点与其他租赁点位的空间和数量关系,指出居住点规模应大致与公交点、公建点和校园点的规模相当。最后,给出武汉市2009年拟建设的800个公共自行车租赁点的布局方案。     

A Provably Secure Asynchronous Proactive RSA Scheme

The drawback of the first asynchronous proactive RSA scheme presented by Zhou in 2001, is that the security definition and security proof do not follow the approach of provable security. This paper presented a provably secure asynchronous proactive RSA scheme, which includes three protocols： initial key distribution protocol, signature generation protocol and share refreshing protocol. Taken these protocols together, a complete provably secure proactive RSA scheme was obtained. And the efficiency of the scheme is approximate to that of the scheme of Zhou.     

两种新型调速方式在船舶电站中的应用前景分析

介绍使用恒频方式和下垂-恒频混合方式进行调速的原理,并结合船舶电站的特点,将这两种新型调速方式同传统的下垂方式进行比较,分析了各种调速方式的优缺点,利用Matlab/Simulink仿真平台搭建船舶电站模型,对各种调速方式进行仿真,初步探索了在船舶电站中使用两种新型调速方式的情况.     

基于地铁乘务资源共享的排班计划优化方法

针对不同线路间列车不跨线情况下的乘务基地和乘务员共享问题开展研究,分析乘务资源共享，在传统排班模型基础上考虑乘务员跨线值乘，班次出退勤地点比例及其鲁棒性优化，建立乘务排班计划集合覆盖模型。针对乘务资源共享后多线协同优化引起的问题规模显著增大，以连续值乘区段为最小值乘任务单元构建网络图，引入分层结构，多级的汇点和源点，以及跨线就餐和间休弧等以满足班次的可行性约束。构建对应不同出退勤地点属性的网络图集合，将定价子问题转化为网络图集合的最短路问题以进行列生成法求解。案例结果表明：相比于分线单独优化，乘务资源共享可为乘务员提供更多的出退勤地点选择，显著降低其通勤时间；此外乘务资源共享可少量节省乘务班次数，提高排班计划效率。     

感知乘客心理的出租车动态合乘优化方法

为研究考虑乘客感知的动态合乘问题，本文提出一种改进的算法框架。基于可行出行对概念，构建乘客满意度最大、出行时间最少的多目标线性规划问题，将合乘问题转化为车辆和乘客间的线性分配问题，并采用基于精英策略的人工蜂群算法(Elitism based Multi-Objective Artificial Bee Colony，EMOABC)求解。根据海口市出租车订单数据建立算例，实验结果表明，该算法框架能够实时提供优质动态合乘方案。相比单纯优化出行效率，考虑乘客心理的合乘策略，相对提高12%的乘客满意度，服务率等方面也有较好表现。     

不同主导权结构下的双渠道供应链定价策略及协调机制研究

基于制造商开辟线上直销渠道与线下零售渠道构成双渠道供应链的背景下,结合实际的服务影响因素,对不同主导权结构下双渠道供应链各成员的定价策略和协调机制进行研究。分别构建制造商主导、零售商主导、垂直均衡三种分散决策下的两阶段Stackelberg博弈模型,研究发现相较于集中决策,分散决策下供应链成员在价格、需求、利润上均有所损失。为缓解渠道之间的矛盾与冲突,引入一种双向收益共享契约用于协调供应链。研究表明,在一定的收益共享范围内,双向收益共享契约可以完美协调供应链;对于主导企业而言,主导权越向自身集中,所需共享的收益比例也越小;随着零售商服务水平的增大,制造商的利润不断增大,零售商的利润不断减小,供应链整体利润呈先增后减趋势。     

Dynamic impedances and load carrying mechanism for skirted foundations

Dynamic impedances of foundations include dynamic stiffness and damping which have important effect on the internal forces in the structure. In some cases, such as offshore wind turbines, the influence of the foundation impedances on the system's natural frequency and overall damping could potentially have a significant effect on the fatigue life of the structure. The vertical, horizontal and rocking impedances of a skirted foundation (also termed bucket foundation in offshore wind industry) embedded in a fully saturated poroelastic seabed are addressed in this paper. The vertical impedance is most relevant for jacket foundations supported on three or four bucket foundations, while horizontal and rocking impedances are applicable for mono-bucket foundations. The dynamic vibration problems are solved semi-analytically with the help of dual integral equations and Green's functions. Numerical results for dynamic impedances are obtained; damping ratio are also obtained to show the importance of radiation damping for bucket foundations, even at very small excitation frequencies. The influence of length-to-radius ratio, Poisson's ratio, permeability of soil, excitation frequency and thickness-to-radius ratio on the impedances are also studied. Besides, the dynamic load sharing among the top plate, bucket shaft and bucket tip is obtained for vertical load, horizontal load and moment to shed light on the carrying mechanism of bucket foundation at dynamic working loads. It is found that for a rigid bucket foundation, even when the length-to-radius ratio is small (e.g. l/a = 1.0), most of the loads are carried by the shaft, while the top plate and tip of the bucket take only a small portion of the loads. The results of this study will be helpful for understanding the load-carrying mechanism of offshore bucket foundations for normal operation conditions.     

面向自组织平衡的共享电动汽车调度优化方法

针对共享电动汽车运营中出现的站点车辆供需不平衡及人工调度成本过高等问题，提出面向自组织平衡的共享电动汽车调度优化方法.利用共享电动汽车站点选择行为数据，构建用户取车站点选择MNL(Multinominal Logit)模型，分析用户的站点选择行为；构建面向各站点车辆供需自组织平衡的站点间车辆调度优化方法，即通过车辆动态折扣策略引导用户改变默认的最近取还车站点，在运营结束后以运营企业的调度总成本最小为目标，建立人工调度优化模型并应用禁忌搜索算法求解；最后，选取北京市海淀区部分共享电动汽车站点进行算例分析.结果表明：本文提出的优化方法与无动态折扣策略相比，调度总成本降低了 4.5%，人工调度成本降低了21.1%，人工调度任务数减少了8.3%.     

Carbon emission from urban passenger transportation in Beijing

Urban passenger transport significantly contributes to global greenhouse gas emissions, especially in developing countries owing to the rapid motorization, thus making it an important target for carbon reduction. This article established a method to estimate and analyze carbon emission from urban passenger transport including cars, rail transit, taxis and buses. The scope of research was defined based on car registration area, transport types and modes, the stages of rail transit energy consumption. The data availability and gathering were fully illustrated. A city level emission model for the aforementioned four modes of passenger transport was formulated, and parameters including emission factor of electricity and fuel efficiency were tailored according to local situations such as energy structure and field survey. The results reveal that the emission from Beijing’s urban passenger transport in 2012 stood at 15 million tonnes of CO₂, of which 75.5% was from cars, whereas car trip sharing constitutes only 42.5% of the total residential trips. Bus travel, yielding 28.6 g CO₂, is the most efficient mode of transport under the current situations in terms of per passenger kilometer (PKM) emission, whereas car or taxi trips emit more than 5 times that of bus trips. Although a decrease trend appears, Beijing still has potential for further carbon reduction in passenger transport field in contrast to other cities in developed countries. Development of rail transit and further limitation on cars could assist in reducing 4.39 million tonnes CO₂ emission.