Model and algorithm for an unpaired pickup and delivery vehicle routing problem with split loads

This paper addresses the routing problem with unpaired pickup and delivery with split loads. An interesting factor of our problem is that the quantity and place for pickup and delivery are decision variables in the network. We develop an easy-to-implement heuristic in order to gain an efficient and feasible solution quickly. Then, a local search algorithm based on the variable neighborhood search (VNS) method is developed to improve the performance of the heuristic. Computational results show that the proposed VNS method is able to obtain an optimal or near optimal solution in reasonable time for the formulated problem.     

基于DEA-C^2R模型的区域交通运输协调效率分析

交通运输是社会经济发展的基础。通过提高不同交通运输方式之间的协调效率可以实现同等交通规模下交通综合运输能力的提高。选取不同交通方式的合理指标和数据,采用数据包络分析的方法对不同交通运输方式之间的运行效率进行分析,通过效率变化情况说明区域交通运输主要构成方式之间的协调配合水平。实证研究结果表明,通过不同交通方式之间的协调效率提高,可以减少交通对土地、能源和环境影响,实现区域交通运输能力的提高。     

城市物流平台:IT解决方案和技术平台

城市物流主要由两部分组成:城市物流运营系统和城市物流平台。城市物流平台提供了整体的IT解决方案和技术设备以支持城市物流运营。本文阐述了IT解决方案如何支持城市物流运营的各个方面,从而使得城市物流各技术层面和其在城市物流平台中的作用更加高效和经济。城市物流平台也通过采用最新的节能技术来实现可持续性发展。     

广东省交通基础设施与经济增长的关系:基于协整分析的实证研究

文章采用经济计量分析方法,实证考察了1978～2008年间广东省交通基础设施与经济增长之间的长期均衡关系和Granger因果关系。结果表明:公路通车里程与和总收入之间的协整关系不稳定;货物周转量、旅客周转量与总收入之间存在正相关关系;货物周转量、旅客周转量是总收入的格兰杰原因。     

Modeling tourism impacts on air pollution: The case study of PM10 in Mallorca

Tourism has begun to be acknowledged as being a significant contributor to the increase in environmental externalities, especially to climate ch ange. Various studies have started to estimate and compute the role of the different tourism sectors that contribute to greenhouse gas (GHG) emissions. These estimations have been made from a sectorial perspective, assessing the contribution of air transport, accommodation or other tourism-related economic sectors. In contrast with this and in order to evaluate the impact of tourism on air pollution from a joint perspective, this paper explores the relationship between daily concentrations of PM₁₀ and the number of tourists in Mallorca (Spain). The results show that the daily stock of tourists is not only a significant predictor of air pollution concentration levels but also a variable whose inclusion improves the standard specification of urban air pollution models that have the common feature of using weather conditions as main explanatory variables. Furthermore, by using a Generalized Additive Model in its semi-parametric form it is shown that a 1% increase in tourist numbers can be related to up to a 0.45% increase in PM₁₀ concentration levels.     

不完全信息条件下商业集群形成的问题研究

商业集群在人们生活中所起的作用日益重要,针对国外许多大型商业集群,如购物中心等通常都建立在郊区的情形,文章借助于Salop.S.C的环形市场模型,对不完全信息条件下商业集群形成的原因进行了分析,得出的结论是:在不完全信息条件下,由于运输成本的存在,消费者对欲购商品的最优搜寻是从商业集群处开始。由于商业集群的魅力所在,就导致了消费者有可能舍近求远,直接到距离较远的商店集聚区进行购物,而不是选择在距离较近的孤立商店购物。据此给出的政策性建议是:当我们在进行城市建设规划时,在交通设施比较完备的条件下,为了节约市区的稀缺资源,可以有选择的在郊区建立一些商业集群,如大型购物中心等,这样既可以有效缓解市内交通拥堵的压力,也可以有效提高资源的配置效率。     

An empirical analysis of effects of gasoline price change on transportation behavior in Japan,with consideration of regional differences

This empirically analyzes the effect of gasoline price change on various aspects of surface transport behavior comprehensively, with consideration of regional differences as to whether or not the region includes a major metropolitan agglomeration area (hereafter, “megalopolis”), by means of carefully arranging yearly time-series data from fiscal 1987 to fiscal 2008 in Japan. The aim is to look at common as well as different effects among regions and to draw policy implications relating to fuel price, as well as to fuel tax, towards developing a low-carbon transport system, which are applicable to other countries including emerging countries where a demographic disparity between megalopolis areas and rural areas might be increasing. The methodology includes the multiple regression models complemented by the 1st order auto-regressive models of error terms, where the elasticities of gasoline price and those of income regarding usage of personal automobiles, of public transport and of passenger railways with or without periodic tickets, and fuel consumption on cars, as well as ownership of various types of cars, are estimated for individual gross-regions. In both gross-regions, higher gasoline prices are commonly shown to be related to lower ownership of larger private passenger cars, higher ownership of light cars, lower ownership of the total private passenger cars, lower passenger-km per capita in cars, lower fuel consumption on cars and higher transit ridership. The result suggests general automobile-fuel-price policy implications, the extent of which is differentiated by spatial characteristics, and estimates the adverse effect of the possible abolition of the provisional gasoline tax rate on the emissions in both gross-regions. The application of result is also tried in exploring effect of other policy measures such as expressway tolls.     

A supply chain-transport supernetwork equilibrium model with the behaviour of freight carriers

This paper presents a supernetwork equilibrium model integrating supply chain networks with a transport network, namely, a supply chain-transport supernetwork equilibrium model. The model takes into account the behaviour of freight carriers and transport network users to endogenously determine the transport costs generated in the supply chain networks. The interaction between transport network and supply chain networks can also be examined. Results of the numerical tests reveal that the improvement of transport network could enhance the efficiency of supply chain networks. The paper makes contributions to modelling of supply chain networks as well as to that of transport networks.     

城市客运交通系统结构研究

在解析城市客运交通系统合理结构的基础上,根据居民出行方式选择随距离和综合交通条件而变化的内在规律,以居民出行距离分布特征为基础,论证常规公交与城市轨道交通出行全过程广义效用值边际效应,综合构建城市客运交通方式出行选择模型。以某中心城市为例,计算结果表明:以出行距离分布特征为基础,考虑城市综合交通条件,结合未来客运结构辨识而建立的城市出行方式选择模型具有较好的拟合特征和适用性。     

Transport problems that matter - social and psychological links to transport disadvantage

This paper presents an analysis exploring self-reported measures of transport disadvantage and how these relate to social exclusion and well-being in Melbourne, Australia. A sample of 535 individuals sourced from a household survey explores ratings of 18 types of transport problems. The questionnaire also measured social exclusion represented in five dimensions including income, unemployment, political engagement, participation in activities and social support networks. Well-being was also measured adopting standard psychological measures of ‘Satisfaction with Life’, ‘Personal Well-being Index,’ ‘Positive Affect’ and ‘Negative Affect’.A factor analysis of self-reported transport difficulties identified four statistically significant sub-scales (‘transport disadvantage’, ‘transit disadvantage’, ‘Vulnerable/Impaired’ and ‘rely on others’) which together account for 57% of the variance in the responses.Analysis established that those with high self-reported transport problems were more likely to be located in fringe and remote parts of the city and lived in areas where it was not possible to walk to a local shop. However all groups made an average number of trips per day (except the ‘Vulnerable/Impaired’ group which make fewer trips) suggesting that self-reported transport disadvantage is unrelated to realised mobility. Analysis further established that only the ‘Vulnerable/Impaired’ group was associated with social exclusion and that they also had the lowest values of well-being compared to other groups.Overall findings confirm the methodological concerns associated with the use of self-reported measures of transport problems as a basis for defining transport disadvantage. The majority of those with high self-reported transport problems did not travel less than the survey sample as a whole and they were not associated with social exclusion. However the ‘Vulnerable/Impaired’ group was the exception, displaying a significantly higher association with social exclusion and lower well-being.The findings suggest which aspects of transport disadvantage are likely to be of greater concern for social policy. A concentration of research and policy on issues and social groups associated with the ‘Vulnerable/Impaired’ factor would be more effective in reducing social exclusion. Transport problems associated with this group including physical access to transport, knowing where to go and feeling safe from theft or attack when travelling may deserve higher priorities for attention. In addition those associated with the ‘Vulnerable/Impaired’ factor including older retired females and those who are more likely to be looking after someone with an illness or disability are clearly a high risk group and should warrant positive discrimination in transport and social policy.