The effects of open skies agreements on transatlantic air service levels

This paper examines the effects of Open Skies agreements on service levels in transatlantic aviation markets. Our route analysis reveals that Open Skies agreements between European countries and the US have resulted in both increases and decreases in service levels. Of the 22 European countries with US Open Skies agreements in place by 2007, only seven demonstrated increases in service levels while six showed reductions. Five countries saw no significant change and the remaining four have yet to receive direct transatlantic service, suggesting that liberalization alone does not lead to service level increases.     

Collaboration decisions on disruption recovery service in urban public tram systems

This research focuses on the decisions on recovery services to deal with short-term disruptions in public tram systems. The disruption recovery approach used in Munich, Germany - the best service acclaimed by the public, is adopted as the basis to examine whether to collaborate with a taxi company to provide the recovery service and how to price to compensate the service. The two involving parties’ decision functions with the taxi’s average arrival time as the leading decision variable are formulated and analyzed. Both theoretical and numerical sensitivity analyses are conducted to shed lights on the critical factors affecting the decisions.     

Design of international assembly systems and their supply chains under NAFTA

The purpose of this paper is to provide a decision support aid for the strategic design of an assembly system in the international business environment created by NAFTA. The strategic design problem is to prescribe a set of facilities, including their locations, technologies, and capacities, as well as strategic aspects of the supply chain, selecting suppliers; locating distribution centers; planning transportation modes; and allocating target levels (i.e., amounts) for production, assembly, and distribution. The objective is to maximize after-tax profits. This paper presents a mixed integer programming model that represents the complexities of the international design problem as well as relevant enterprise-wide decisions in the US–Mexico business environment under NAFTA. It deals with a broad set of design issues (e.g., bill-of-material restrictions, international financial considerations, and material flow through the entire supply chain) using effective modeling devices (e.g., linearizing non-linearities that arise in modeling transfer prices and allocating transportation charges). Examples demonstrate how managers might use the model as a decision support aid.     

The impact of market opening on the supply of interregional train services

A stepwise deregulation of all interregional passenger rail services in Sweden was legally completed in 2010. The incumbent operator (SJ) thereby lost the sole rights to commercial services. The most evident supply increase is the establishment of services in the low-cost niche, which rather complements than competes with the incumbent’s supply. Public Transport Authorities’ (PTAs) joint services have however resulted in strong competition on at least one main line.Despite a period of almost five years since deregulation, the potential effects of the market opening have not yet fully materialised. The business risk for commercial rail operators seems to be much greater than for other modes like air and long distance coach services. SJ have also during decades of deregulated intermodal and years of intramodal competition developed their products and skills and seem well prepared for competition.     

The optimization of the closed-loop supply chain network

This paper develops a model of a general closed-loop supply chain network, which includes raw material suppliers, manufacturers, retailers, consumers and recovery centers. The objective of this paper is to formulate and optimize the equilibrium state of the network by using the theory of variational inequalities. Several examples and figures are used to describe the effects of parameters (the return ratio, the transformation rate of raw materials, and the transformation rate of recyclable products) on the equilibrium shipments and net revenues.     

Concurrent design of product family and supply chain network considering quality and price

We study the problem of concurrent design of a product family and its supply chain (SC) network. Inspired by a real-life case in computer industry, the impact of quality and price in SC demand is investigated. Two different models are proposed, the former maximizes the company’s profit with respect to customers’ priorities on quality and price; the latter is a bi-objective programming, which consider two extreme customer groups: for one group quality has the highest priority and for the other price; the intermediate groups falls between these two. The performance of the models is analyzed through a case problem.     

Dynamics of liner shipping network and port connectivity in supply chain systems: analysis on East Asia

The study of ports in supply chain systems is an emerging area of importance which has drawn more attention from researchers in recent years. This paper presents a new perspective in this research area by examining the calling patterns of container shipping services in order to understand the dynamics of port connectivity and inter-port relationships in the supply chains. Empirical evidence is drawn from four major ports in East Asia, namely Shanghai, Busan, Kaohsiung and Ningbo. The study identifies the shipping capacity, trade routes and geographical regions connected to the ports, shipping lines involved, and the extensity and intensity of inter-port relationships among the four container ports from liner shipping network’s perspective. The findings show that most of the shipping capacity employed on the major east–west trade routes became non-exclusive and involved calls at two or more of the four ports. Port planners, terminal operators and carriers could capitalise on opportunities through exploitation of complementary relationships that exist among the selected ports, such as offering a package for shipping lines to call at a portfolio of terminals owned by the same terminal operator. Policy and research implications as well as recommendations are discussed for various stakeholders concerned with port planning and regional development.     

我国动车组列车供餐方式的思考

根据旅客评价,分析现行动车组供餐存在的主要问题,结合国外铁路列车供餐经验,探讨我国铁路如何推进动车组供餐。     

Quantifying grade effects on vehicle fuel consumption for use in sustainable highway design

The paper develops an analytical formulation that quantifies the effect of vertical grade on vehicle fuel consumption and then illustrates the use of the developed procedure in the identification of the fuel efficient freeway layouts. Specifically, the Virginia Tech Comprehensive Power-based Fuel consumption Model (VT-CPFM) was used to develop the formulation and then applied using 2015's 10 most-sold vehicles in the U.S. and Europe to quantify the vertical grade effect on vehicle fuel consumption rates. An increase in fuel consumption of approximately 140% was found when the roadway grade increased from 0.5% to 6%. The proposed selection procedure uses Geographical Information System (GIS) applications in the design phase to evaluate possible freeway layouts. A multi-criteria analysis is performed to rank the feasible alternatives. The yearly fuel consumed by cars traveling on each feasible layout is then predicted and the alternatives are sorted in ascendingly. If the alternative selected by the multi-criteria analysis gives the least yearly fuel consumption, then that alternative should be constructed. If not, then the alternative that results in the least yearly fuel consumption should be re-evaluated with respect to the one selected by the multi-criteria analysis tool. The proposed procedure is validated using a real case study involving the construction of a new freeway in Cameroon. As much as a 12% difference in fuel consumption was found between the alternative with the least estimated yearly fuel consumption and that selected based on a multiple-criteria decision analysis.     

交通运输基础设施供给方式的新兴古典经济学分析

对于交通运输基础设施作为准公共产品由谁供给目前在学理上没有给出明晰解释,没有深入揭示其选择机理。从新兴古典经济学的角度认为,交通运输基础设施供给方式的选择,取决于该种机制是否最小化了公共物品提供过程中的所有交易成本。     

The impacts of Radio Frequency Identification (RFID) technology on supply chain costs

Radio Frequency Identification (RFID) is regarded as a promising technology for the optimization of supply chain processes since it improves manufacturing and retail operations from forecasting demand to planning, managing inventory, and distribution. This study uses a simulation model to calculate the expected benefits of an integrated RFID system on a three-echelon supply chain obtained through performance increases in efficiency, accuracy, visibility, and security level. The study investigates how the product value, lead time, and demand uncertainty affect the performance of the integrated RFID supply chain in terms of cost factors at the echelon level.     

The influence of green practices on supply chain performance: A case study approach

The main objective of this exploratory paper is to investigate the relationships between green practices of supply chain management and supply chain performance. This relationship is investigated in the context of the automotive industry. Five research propositions are suggested and tested with empirical data derived from five case studies taken from the Portuguese automotive supply chain. The data analysis identifies the most important green practices considered by managers, as well as the performance measures that are most appropriate and most widely used as means to evaluate the influence of green practices on supply chain performance. A conceptual model was derived from the data analysis and it can be used to assess the influence of green practices on supply chain performance. This model provides evidence as to which green practices have positive effects on quality, customer satisfaction and efficiency. It also identifies the practices which have negative effects on supply chain performance.     

The co-opetitive strategy of a closed-loop supply chain with remanufacturing

This paper deals with a strategic issue of closed-loop supply chains with remanufacturing by developing analytic models under cooperative and competitive settings. The primary goal behind analytic formulation is to investigate under what conditions an original equipment manufacturer (OEM) may take a cooperative approach by participating in remanufacturing. In contrast, the OEM may take a competitive approach by letting the third-party firm remanufacture the returned cores and remarket in the secondary market that competes with the new product. Our analysis reveals that the strategic decision depends critically on the costs of remanufacturing and the competition intensity between the two versions.     

Theoretical framework of systems design for the air transportation system including an inherently quantitative philosophy of scenario development

This paper provides an overview of an inherently quantitative scenario philosophy for systems analysis and innovative concept design in the context of the Air Transportation System (ATS). A general perspective of the ATS is visualized in an “atomic model” with surrounding external scenario factors and the aircraft as the key connecting element between the main stakeholders: manufacturers, airlines, air navigation service providers (ANSPs) and airports. An iterative waterfall model is presented, which serves as a mental model of integration and decomposition over cascades of levels of detail from global scenario level to a single technology. The difference between classical scenario technique and a quantitative, yet participatory methodology of developing scenarios for the ATS is described. In order to integrate and decompose over a large span of levels of details, concept design and synthesis is as important as analysis. Further, quantitative scenario development may be considered as the synthesis of a skillful manipulation of a model deck. Scenario Gaming can be a method to simulate the settlement on requirements of complex socio-technological systems with multiple stakeholders and conflicting perspectives under radically changing boundary conditions. Scenario thinking can be an innovative and explorative instrument of participatory futurology, if not reduced to a mere “input for a tool chain”.     

The effects of China's airline mergers on prices

This paper looks at the effects of some of the recent airline mergers in China. Overall, no significant airfare increases are found in a sample of markets served by the merged China Eastern and China Southern after 2002; indeed in most of the markets directly affected airfares declined. This was despite the absence of antitrust laws and enforcement over the period. However, market power was possibly exercised after the mergers in China Eastern's hub-to-hub networks.     

基于旅客评价的客运服务质量影响因素分析

从旅客评价的角度来研究影响客运服务质量的因素。对收集整理的旅客评价信息,运用因子分析法筛选出主要影响因素,并通过最优尺度回归模型对影响程度进行量化分析;对旅客评价信息中的人为干扰因素进行分析和认定,最后结合客运业务工作的实际对结论进行佐证。     

Multistage optimization of the supply chains of biofuels

In this study, a mathematical model that integrates spatial and temporal dimensions is developed for strategic planning of future bioethanol supply chain systems. The planning objective is to minimize the cost of the entire supply chain of biofuel from biowaste feedstock fields to end users over the entire planning horizon, simultaneously satisfying demand, resource, and technology constraints. This model is used to evaluate the economic potential and infrastructure requirements for bioethanol production from eight waste biomass resources in California as a case study. It is found that, through careful supply chain design, biowaste-based ethanol production can be sustained at a compatible cost around $1.1 per gallon.     

The effect of service quality and satisfaction on destination attractiveness of sub-Saharan African countries: the case of Ghana

This paper examines the functional forms of service quality (SQ) and satisfaction in relation to destination attractiveness. It focuses on the varying influence of destination characteristics, customer economics, and demographic variables to explore how SQ might be used to improve value positioning and, therefore, potential attractiveness of Ghana as a destination choice for tourists. Using methods triangulation data collection protocol, the paper finds causal links between SQ and selected composites of destination attractiveness (destination attributes, support services, facilities, and people-related factors) in the degree to which they influence customer satisfaction and return-visit intentions. The paper contributes refreshing insights useful for segmentation marketing, tour planning, and product/service development. The implications are far-reaching when considered alongside the fact that Ghana is relatively a new entrant into the organised tourism marketing arena and has the consequent imperative to scale-up structural and human capabilities to compete effectively with the more established global competitors.     

The effects of removing the Trondheim toll cordon

This article presents the effects of removing the Trondheim toll cordon, which was closed after nearly 15 years of operation on December 31, 2005. The traffic levels, measured as vehicles per hour, in 2006 are compared to traffic levels in 2005. The evaluation also covers the effect on the retail market and possible environmental effects. We also seek to investigate what the traffic levels would have been today if the cordon had still been in operation. We find that the closing of the Trondheim toll cordon has lead to increased traffic levels in the peak hours, with an average increase of 11.3% in the former charging hours of 06:00–18:00. On an average, the hours between 14:00 and 18:00 experienced an increase in traffic of 15.5%, whilst traffic in the evenings and nights decreased. Model results suggest that the removal of the toll cordon has caused the private car to increase its modal share at the expense of passengers per car, public transport and cycling/walking. The increase in the total number of trips would have been more uniformly distributed among the alternatives if the toll cordon had still been in operation.     

大跨度桥上铺设无砟轨道结构设计研究

分析日本、德国、UIC及我国标准中对铺设无砟轨道大跨度桥梁刚度要求,研究和探讨大跨度桥梁梁端道床板稳定性、扣件上拔力计算、大梁缝处轨道结构设计、钢轨伸缩调节器区无砟轨道结构设计等桥上无砟轨道的关键问题,提出结构设计方法,以期为我国大跨度桥上铺设无砟轨道结构设计提供参考。