安全活动对物流企业绩效作用的实证分析

本文以物流企业为调查对象进行问卷调查,通过Bootstrapping和结构方程模型的路径分析,分析了物流安全活动对成本控制,运输效率和企业绩效之间的影响关系.同时,以路径分析结果为基础,提出了推广物流安全实践活动和提高物流企业绩效的意义.结果表明,安全运输实践及安全运输预防管理对成本控制和运输效率都有着显著的积极影响,运输手段安全管理对成本控制有着显著的积极影响,而运输手段安全管理对运输效率产生的影响力在5％的显著性水平下不显著,成本控制对运输效率也产生了显著的积极影响关系,成本控制和运输效率对企业绩效也都有着显著的积极影响.     

Min–Max exact and heuristic policies for a two-echelon supply chain with inventory and transportation procurement decisions

We study the problem in which one supplier delivers a product to a set of retailers over time by using an outsourced fleet of vehicles. Since the probability distribution of the demand is not known, we provide a Min–Max approach to find robust policies. We show that the optimal Min-Expected Value policy can be very poor in the worst case. We provide a Min–Max Dynamic Programming formulation that allows us to exactly solve the problem in small instances. Finally, we implement a Min–Max Matheuristic to solve benchmark instances and show that it is very effective.     

西三角经济圈的合理性分析——基于空间经济学基本原理

通过运用Walter Christaller提出的中心—地方理论,以及空间经济学的基本原理,建立了一个以重庆、成都、西安三地区为支撑点的空间区域经济模型。通过模型分析西三角经济圈的合理性,并为西三角经济的进一步健康发展提出有利建议。     

我国运输服务贸易国际竞争力的测度与比较

本文主要运用近年来我国和世界运输服务贸易强国的各类运输服务贸易进出口数据,借助国际市场占有率（MOR）、贸易竞争力指数（TC）、显示性比较优势指数（RCA）和显示性竞争优势指数（CA）等指标,来综合测度和分析我国运输服务贸易的国际竞争力。分析结果表明,我国运输服务贸易竞争力较低,但整体上呈上升趋势,未来有待进一步提高。根据波特的“钻石模型”,来分析我国运输服务贸易竞争力不高的主要原因,提出必须在转变政府职能,推进大型企业和大型运输企业的联合,加强综合物流设施的建设,加强专业人才的教育和培养等方面采取政策措施。     

曹妃甸港疏运体系优化对策探讨

曹妃甸港作为我国北方地区重要的能源型港口,优化曹妃甸港铁矿石疏港运输体系,提高港口大宗物资铁路运输比例,在更好地满足唐山地区钢铁企业对疏港矿石运输需求的同时,对服务国家运输结构调整和打赢蓝天保卫战具有重要意义。从市场需求情况、铁路疏港运输能力方面分析曹妃甸港疏港运输现状,针对存在的问题,结合曹妃甸港疏运体系面临的形势任务,提出提升综合运输能力、创新运营管理、提升铁路服务水平等曹妃甸港疏运体系优化对策,以打通制约环节,畅通运输堵点,提升路网资源效率。     

Network topology and the efficiency of equilibrium

Different kinds of networks, such as transportation, communication, computer, and supply networks, are susceptible to similar kinds of inefficiencies. These arise when congestion externalities make the cost for each user depend on the other users' choice of routes. If each user chooses the least expensive (e.g., the fastest) route from the users' common point of origin to the common destination, the result may be Pareto inefficient in that an alternative choice of routes would reduce the costs for all users. Braess's paradox represents an extreme kind of inefficiency, in which the equilibrium costs may be reduced by raising the cost curves. As this paper shows, this paradox occurs in an (undirected) two-terminal network if and only if it is not series-parallel. More generally, Pareto inefficient equilibria occur in a network if and only if one of three simple networks is embedded in it.     

Entry controls in taxi regulation: Implications of US and Canadian experience for taxi regulation and deregulation

This paper assesses the effects of entry regulation and deregulation on taxicab availability and service quality based on the experiences of 43 cities and counties in the United States and Canada. The analysis shows that entry controls have quite different impacts in the two basic markets served by taxicabs: the telephone order (dispatch) market and the cab stand/street hail market. Without entry controls, the cab stand and street hail market experiences an oversupply of cabs, leading to deterioration of vehicle and driver quality. Applied to the dispatch market, however, entry restrictions often lead to deficiencies in taxicab availability. The paper reviews the effectiveness of regulatory approaches for each market and for cities with substantial trip volumes in both markets. Approaches include two-tier systems, flexible forms of entry control, company-level entry qualifications, geographic restrictions and service requirements. These approaches and implications for regulation are discussed.     

Making the connections between transport disadvantage and the social exclusion of low income populations in the Tshwane Region of South Africa

To date, the majority of studies which consider transport from a social exclusion perspective have been conducted in the context of the developed world where both income poverty and lack of transport are relative rather absolute states. In a unique departure from these previous studies, this paper explores the relationship between transport and social disadvantage in the development context, the key difference being that income poverty is absolute and where there is much lower access to both private and public transportation generally. Thus, it seeks to explore whether the concept of social exclusion remains valid, when it is the majority of the population that is experiencing transport and income poverty compared with the minority who do so in advanced economies.The paper is based on a scoping study for the Republic of South Africa Department of Transport (RSA DOT), which primarily involved focus group discussions with a range of socially deprived urban and peri-urban population groups living in the Tshwane region of South Africa. In a second departure from previous studies which consider transport and social disadvantage in the development context, the study takes a primarily urban focus. The rationale for this is that theoretically low income urban settlements do not suffer from the lack of transport infrastructure and motorised transport services in the way that more remote rural areas do. The policy issue is therefore less a question of addressing a deficit in supply and more one of addressing particular aspects of public transit service failure, which are more readily amenable to relatively low cost, manageable, small-scale national and local policy interventions.A primary aim for the study was to reinvigorate cross-government debate of these issues in the hope of breaking South African government’s long-standing and persistent policy inertia in the delivery of equitable and socially sustainable urban transport systems.