蚁群算法解决有时间窗的车辆优化调度问题研究

有时间窗的车辆路径问题（Vehicle Routing Problem With Time Windows，VRPTW）属于NP-Hard问题，严格的时间约束使VRFTW非常复杂。应用蚁群算法（Ant Colony Algorithm,ACA）思想来解决VRPTW。对已有蚁群算法解决车辆路径优化问题（VRP）的模型进行改进，对算法中相应的转移规则和轨迹更新规则进行了重新设定，改进了算法转移策略和信息素更新策略。给出了算法的实现步骤。通过算例分析，将计算结果与遗传算法（GA）和粒子群算法（PSO）作了比较，对模型和算法的正确性、高效性、适用性进行了验证。实验结果表明，ACA可以快速、有效求得VRFTW的优化解，是求解VRFTW的一个较好方案。     

The Foreign Trade and Sectoral Impact of Truck Road Pricing for Cross-Border Trade

Truck road pricing is on the brink of beingintroduced in a number of European countries.The experience gained from Switzerland, thefirst country worldwide to implement such adistant-dependent pricing scheme, has provedinvaluable. Nevertheless, significant questionsstill remain. The present paper attempts toprovide some clarity by analysing the welfareand sectoral impact resulting from theintroduction of truck road pricing with respectto foreign trade. It is shown that this impactcan be separated into four effects: the pureterms of trade effect, the tax revenue effect,the transit tax revenue effect and the resourcegain effect (resources set free by a reductionin transport activity). A CGE simulation ofeach of these effects identifies theirquantitative implications. Out of the foureffects the pure terms of trade effect turnsout to dominate at both the sectoral andaggregate level. It triggers a trade-inducedwelfare loss. The tax revenue effect, and lessso the transit revenue effect, mitigate thisloss. For a full road transport costinternalization a trade-induced welfare loss isquantified for Austria at 1.3%. Sensitivity ofthis and other aggregate variables is high withrespect to household reaction to transport taxrevenue refunding. The trade-induced welfareloss of variable size as explored in thisarticle counterbalances a fraction of thewelfare gain due to internalization.     

我国推行资产证券化的障碍分析与对策

资产证券化在我国作为一种新型的金融工具，有着广阔的发展前景，但是在现行的制度框架下，资产证券化的发展面临着很多障碍。本文就我国推行资产证券化时所面临的障碍和解决的对策进行论述。     

交通事故引起的排队长度及消散时间的估算

传统的排队论理论单纯使用需求量和通行能力关系推算排队长度,由于其未考虑车流波动的影响,从而使估算结果与实际出入很大。现用车流波动理论分析发生交通事故后路段上车辆排队的形成与消散过程,推导出估算排队长度与消散时间的公式,并通过算例说明根据估算值提前分流,可提高道路的通行能力。     

Attitudes towards Tax Levels: A Multi‐Tax Comparison*

We analyse Swedes' opinions about the levels of 11 different taxes to see which taxes people are most averse to and why. The most unpopular tax is the real estate tax, while the corporate tax is the least unpopular. We find a strong self‐interest effect in tax attitudes and that knowledge and education increase support for corrective taxes.     

多温区冷藏车温度场测试实验分析

针对多温运输过程中温度变化复杂的问题,以实验式展开研究。实验将冷冻厢/冷藏厢的温度分别设置为-20℃/10℃,分析了车厢的温度分布情况和车厢内不同位置的温度变化及相互之间的影响,并探究温度产生波动的原因。进而有针对性地提出多温区冷藏车的操作方案,供加强冷链物流过程中的货物品质、降低货物损耗率、节约能源、减少物流成本等方面借鉴与参考。     

论机动车第三者责任保险中“第三者”的界定

先根据合同相对性原理对机动车第三者责任保险中的“第三者”作出一般性解释,然后介绍我国机动车第三者责任保险对“第三者”外延的界定,再对相关界定作进一步的分析和评价,认为根据我国当前的相关立法环境可以将机动车第三者责任保险的被保险人调整为车辆实际使用人;被保险人不应该是机动车第三者责任保险中的“第三者”;从事驾驶工作的雇用...     

燃料电池电动汽车用大功率Buck DC/DC变换器研究

针对燃料电池电动汽车用大功率DC/DC变换器的要求,文章提出了一种新型的柔性换流BuckDC/DC变换器拓扑,并重点分析了该拓扑结构的特点和工作过程。通过在常规的Buck电路中增加少量L、C、D器件,使主功率开关管和功率二极管可以平缓地切换工作电流,该方法提高了变换器可靠性和电磁兼容性。用Pspice对该电路拓扑进行了仿真,并给出了基于该电路拓扑研制的90kWDC/DC变换器的开关波形和效率曲线。该变换器已经成功地应用在国内自主研发的燃料电池城市客车中,各项技术指标均满足使用要求。     

燃料电池电动汽车用大功率Buck D/DC变换器研究

针对燃料电池电动汽车用大功率DC／DC变换器的要求。文章提出了一种新型的柔性换流Buck DC／DC变换器拓扑，并重点分析了该拓扑结构的特点和工作过程。通过在常规的Buck电路中增加少量L、C、D器件，使主功率开关管和功率二极管可以平缓地切换工作电流，该方法提高了变换器可靠性和电磁兼容性。用Pspice对该电路拓扑进行了仿真，并给出了基于该电路拓扑研制的90kW DC／DC变换器的开关波形和效率曲线。该变换器已经成功地应用在国内自主研发的燃料电池城市客车中，各项技术指标均满足使用要求。     

R&D portfolios in environmentally friendly automotive propulsion: Variety, competition and policy implications

In this article, we analyze R&D portfolios in environmentally friendly automotive propulsion including alternative fuel options. We argue that at the current stage of development, substitution of conventional car technology by a new automotive propulsion technology may lead to premature lock-in of suboptimal technology. To avoid such lock-in, one should value the variety of current R&D activity that enables organizations to learn from multiple options and to create spillovers between options. We further argue that the existence of technological variety is not a sufficient condition to avoid lock-in. Organizational variety is also required to sustain competition and avoid the dominance of few firms that possibly enforce a suboptimal technology within the sector. To assess whether recent developments in R&D have led to both technological variety and organizational competition, we analyze United States Patent and Trademark Office (USPTO) patents in low-emission vehicles (LEVs) during the period 1980–2001 using entropy statistics. Results show that both technological variety and organizational competition have increased steadily since the early nineties, suggesting that premature lock-in is unlikely to occur. From an environmental policy evaluation perspective, we consider the findings as a positive evaluation of the 1990 Californian Low Emission Vehicle program.