How to road price in a world with electric vehicles and government budget constraints

In this paper we examine what characterizes second-best road prices targeting external costs from driving electric (EV) and conventional (ICEV) vehicles when there are distortionary labor taxes and binding government budget constraints. Further, we examine how this second-best pricing fits with government set goals of reducing CO₂ emissions. The paper further develops an analytical framework for assessing first- and second-best road prices on vehicle kilometers, extending it to include EVs and externalities that vary geographically and by time of day. We find that optimal road prices largely vary with external cost, but are also significantly affected by the interactions with the rest of the fiscal system. Not surprisingly, the highest road prices should be for ICEVs in large cities during peak hours due to high external costs. More surprisingly, we find that the road price for ICEVs in rural areas should be lower than that for EVs due to large fiscal interaction effects. These road prices give large welfare gains, but they lead to no reduction in carbon emissions when applying the currently recommended social cost of carbon.     

.NET泛型技术的研究与分析

介绍了.NET泛型机制的性能、安全和重用性,分析了泛型在类、方法、结构、接口、委托上的应用及其注意事项,并研究了泛型约束与继承这两项重要技术在泛型上的具体实现;将.NET泛型与C＋＋模板、Java泛型进行了对比分析;对.NET泛型技术进行了总结,展望了泛型在.NET开发中的应用前景.     

SX2150K系列车型平衡轴密封改进

针对SX2150K系列越野车平衡轴渗漏问题,进行了零部件结构分析和渗漏机理分析,提出了防止平衡轴渗漏的改进思路与解决方法。     

带平衡约束三维装箱问题的双层混合遗传算法

针对带重心平衡约束的三维装箱问题,基于框架式布局思想,设计双层混合遗传算法进行求解.根据装载物的特性定义核心货物元素及进行核心堆的构造,再结合极点、锚距等概念提出适合货物平衡装载的布局过程;在典型布局形成初始框架基础上,通过双层混合遗传算法的内、外层搜索分工与协作,获得货物最优装载方案.基于标准算例的实验及对比分析,证明所提出方法在提高装载率及实现重心平衡方面取得了较好效果.     

单缸柴油机新型平衡机构设计研究

分析了单缸柴油机新型平衡机构的基本原理,指出剩余惯性力比的大小与连杆比和偏心率有关,并提出了用非匀速平衡机构减小激励力的方法。以S1115柴油机为载体,找出理论最优偏心率,在尽量保持结构继承性的原则上对其进行改进,对改进后的机构及其机构运动关系进行了详细分析,并提出了用齿侧间隙消除机构减小冲击载荷和冲击噪声的原理,通过对不同的机构进行多体动力学仿真分析,发现改进后的平衡机构能降低噪声且有较好的平衡性。     

拖车离合器鼓动平衡工装设计及应用

针对某出口俄罗斯的拖车因离合器鼓旋转产生的不平衡惯性力引起拖车的剧烈振动的状况,对拖车的离合器鼓进行了动平衡工装设计及校正试验,校正及试验后大大降低了拖车系统的振动,同时也提高了盘类转子动平衡试验及应用的能力。     

土压平衡盾构施工地铁引起的地表沉降分析

以深圳地铁五号线的盾构施工为工程背景,对洪浪站-兴东站区间盾构隧道的施工进行了监控量测,根据实测数据,对土压平衡盾构法隧道施工引起的土体变形特性进行了分析,研究了地表沉降过程及其分布规律,结合理论研究与三维数值计算,将有限元模拟结果与实测数据进行对比,二者吻合程度较好。     

停站约束下多列车运力分配与定价联合决策模型

基于收益管理的思想将铁路货运市场分为合同市场和自由市场,针对铁路运输网 络中每个OD,合同市场的运力需求服从正态分布,自由市场的运力需求表现为价格的反应函 数并辅以随机变量来反映需求的波动性.同时考虑列车的停站约束条件,以列车的停站方案、2 个市场运力分配方案和自由市场的运价为决策变量,构建多列车运力分配和定价联合决策的 混合整数概率非线性规划模型,利用粒子群算法对模型求解,通过算例验证了模型和算法的 有效性.最后以双市场统一定价策略为对比方案,结果表明,本文所建立的模型可有效提高收 益,且自由市场需求波动越大,收益优化越显著.     

Spillback congestion in dynamic traffic assignment: A macroscopic flow model with time-varying bottlenecks

In this paper, we propose a new model for the within-day Dynamic Traffic Assignment (DTA) on road networks where the simulation of queue spillovers is explicitly addressed, and a user equilibrium is expressed as a fixed-point problem in terms of arc flow temporal profiles, i.e., in the infinite dimension space of time’s functions. The model integrates spillback congestion into an existing formulation of the DTA based on continuous-time variables and implicit path enumeration, which is capable of explicitly representing the formation and dispersion of vehicle queues on road links, but allows them to exceed the arc length. The propagation of congestion among adjacent arcs will be achieved through the introduction of time-varying exit and entry capacities that limit the inflow on downstream arcs in such a way that their storage capacities are never exceeded. Determining the temporal profile of these capacity constraints requires solving a system of spatially non-separable macroscopic flow models on the supply side of the DTA based on the theory of kinematic waves, which describe the dynamic of the spillback phenomenon and yield consistent network performances for given arc flows. We also devise a numerical solution algorithm of the proposed continuous-time formulation allowing for “long time intervals” of several minutes, and give an empirical evidence of its convergence. Finally, we carry out a thorough experimentation in order to estimate the relevance of spillback modeling in the context of the DTA, compare the proposed model in terms of effectiveness with the Cell Transmission Model, and assess the efficiency of the proposed algorithm and its applicability to real instances with large networks.     

多QoS约束的动态多播路由算法

对具有延迟、带宽和低代价等多OoS约束的多播路由算法进行研讨，描述了一种适应于研究OoS多播路由的网络模型，提出一种具有多OoS约束的动态多播路由算法（DMRAQoS），DMRAQoS试图有效地减少生成多OoS约束的多播树的开销，使多播组成员能动态地加入／退出多播会晤，且不干扰现有的多播树。仿真实验结果表明，与YAM和QoSMIC比较，DMRAOoS具有较小的延时和较少的代价。