Robust grain supply chain design considering post-harvest loss and harvest timing equilibrium

This paper presents a bi-level robust optimization model, where a food company maximizes its profit and minimizes post-harvest loss by optimally deploying grain processing/storage facilities and determining grain purchase price, while a group of spatially distributed non-cooperative farmers determine harvest time, shipment, storage, and market decisions under yield uncertainty and market equilibrium. The non-cooperative behavior of the food company and the farmers is represented by a bi-level Stackelberg leader follower’s game model with mixed-integer decision variables. The proposed model and solution approach are applied to case studies for Illinois and Brazil.     

Port service chains and port performance evaluation

This paper provides a novel and unique methodology for evaluating the effectiveness performance of a port’s individual services by utilizing the concept of a port service chain – a service network utilized by a port’s service providers in the provision of the port’s services that accounts for the quality-of-service relationships among the services. If such relationships are ignored, the resource allocations by the port’s service providers to improve the quality of their port services will either over- or underestimate the amount of resources needed. A cooperative port service chain will always (under certain conditions) be more effective than a non-cooperative port service chain.     

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.     

Design of a bi-objective reliable healthcare network with finite capacity queue under service covering uncertainty

This paper designs a reliable healthcare network. Under limited capacity, queue of patients may deteriorate the condition and leads to risk of death. Consequently, it is vital to investigate a queue system that considers the condition and changes over the time. Besides, treatment units just serve patients that are in their coverage threshold, while this threshold is affected by several factors. This paper considers number of patients and covering threshold under uncertainty. To handle uncertainty, an integrated approach is proposed. Two meta-heuristic algorithms are developed for the given problem. Finally, we carried out experiments to assess proposed model and approaches.     

A polynomial-time heuristic for the quay crane double-cycling problem with internal-reshuffling operations

One of great challenges in seaport management is how to handle containers under reshuffling, called reshuffles. Repositioning reshuffles in a bay (internal reshuffling) can improve the efficiency of quay cranes and help ports to reduce ship turn-around time. This paper studies the quay crane double-cycling problem with internal-reshuffling operations, and presents a fast solution algorithm. To reduce the number of operations necessary to turn around a bay of a vessel, the problem is first formulated as a new integer program. A polynomial-time heuristic is then developed. The analysis is made on the worst-case error bound of the proposed algorithm. Results are presented for a suite of combinations of problem instances with different bay sizes and workload scenarios. Comparisons are made between our algorithm and the start-of-the-art heuristic. The computational results demonstrate that our model can be solved more efficiently with CPLEX than the model proposed by Meisel and Wichmann (2010), and the proposed algorithm can well solve real-world problem instances within several seconds.     

Coordinating pricing and inventory decisions in a multi-level supply chain: A game-theoretic approach

This paper concerns coordination of enterprise decisions such as suppliers and components selection, pricing and inventory in a multi-level supply chain composed of multiple suppliers, a single manufacturer and multiple retailers. The problem is modeled as a three-level dynamic non-cooperative game. Analytical and computational methods are developed to determine the Nash equilibrium of the game. Finally, a numerical study in computer industry is conducted to understand the influence of the market scale parameter and the components selection strategy on the optimal decisions and profits of the supply chain as well as its constituent members. Several research findings have been obtained.     

A scenario planning approach for the flood emergency logistics preparation problem under uncertainty

This paper aims to develop a decision-making tool that can be used by government agencies in planning for flood emergency logistics. In this article, the flood emergency logistics problem with uncertainty is formulated as two stochastic programming models that allow for the determination of a rescue resource distribution system for urban flood disasters. The decision variables include the structure of rescue organizations, locations of rescue resource storehouses, allocations of rescue resources under capacity restrictions, and distributions of rescue resources. By applying the data processing and network analysis functions of the geographic information system, flooding potential maps can estimate the possible locations of rescue demand points and the required amount of rescue equipment. The proposed models are solved using a sample average approximation scheme. Finally, a real example of planning for flood emergency logistics is presented to highlight the significance of the proposed model as well as the efficacy of the proposed solution strategy.     

Synergies in destination image management: a case study and conceptualisation

This paper addresses the question of how operators and destination authorities work within a destination region, illustrating a method by which the problems resulting from different geographical scales and objectives of business units can be tackled through co‐operative marketing within a strong destination image. Following a review of the literature, a case study covering the research underpinning a cooperative marketing programme involving hotels in Port Douglas, Tropical North Queensland (TNQ) is presented. The research methodology is outlined. The policy implications of the findings for the State Tourist Organisation and for organisations involved in destination image management are considered, and a conceptual model of cooperative marketing at the destination level is proposed. Copyright © 2002 John Wiley & Sons, Ltd.     

2-Stage stochastic programming approach for hub location problem under uncertainty: A case study of air network of Iran

In this paper 2-stage stochastic programming has been developed for formulating stochastic uncapacitated multiple allocation hub location problem. This problem is studied under three cases. The first, stochastic demand, the second, stochastic transportation cost and the third, integrated stochastic, which is compounded of first and second cases. A case of air network in Iran is used to evaluate proposed formulations and computational results obtained by GAMS are presented. The results show that considering uncertainty into formulation could cause in different solutions.     

Tacit collusion between two terminals of a port

With the recent deregulation of container service rates and the establishment of more joint venture terminals in China, the separation of ownership and operation of container terminals will make price competition fierce in one port area. In this study we present an analysis of the price competition between two container terminals using a two-stage non-cooperative game theoretical model. Our main finding is that price-matching strategies facilitate tacit collusion between container terminals. Numerical simulation is applied to the container terminals at the Yangshan Deepwater Port in Shanghai, China.     

空铁联运协同下的跨域航空服务网络优化

为解决各机场竞相开设航班所导致的空域航班密度过大及与之相伴的航班延误问题,从需求管理的角度研究空铁联运网络优化及空铁协调下的客运组织问题。在建立由航班、高速铁路和空铁换乘系统构成的复合网络的基础上,以城市圈为区域单元,构建考虑公平性约束和高速铁路对航班喂给条件的上层空铁联运跨域航空服务网络优化模型和下层乘客路径选择模型的双层优化模型,旨在最小化区域间的出行总时间。在实证分析部分,对研究区域进行计算结果分析,并分析公平性指数对区域间运输系统效率的敏感性,为跨域航空服务网络优化研究提供参考依据。     

Liner hub-and-spoke shipping network design

This paper proposes a liner hub-and-spoke shipping network design problem by introducing the concept of a main port, as well as some container shipping constraints such as multi-type container shipment and transit time constraints, which are seldom considered in the previous studies. It develops a mixed-integer programming model with nonconvex multi-linear terms for the proposed problem. An efficient genetic algorithm embedded with a multi-stage decomposition approach is developed to solve the model. Numerical experiments are carried out to assess the effectiveness of the proposed model and the efficiency of the proposed algorithm.     

Analysis on bargaining about global climate change mitigation in international aviation sector

Understanding the basic interaction mechanism among nations surrounding the CO₂ emissions is critically important for the policy formulation analysis in aviation sector at present, especially for market-based measures such as emission allowance trading. We performed simulation analysis of the effects on pricing of emission allowances by including major players such as China and India into the hypothetical global CO₂ emission trading scheme according to non-cooperative game framework. In the presence of a negative public good, i.e., CO₂, we extended the Lindahl–Bowen–Samuelson condition to include a class of uncertainty typical in climate change policy into utility. By using the result, we explained, with some numerical examples, the welfare effects caused by the changes of factors, such as level of uncertainty, degree of risk averse, asymmetric utility structure, initial allocation among players, based on our model surrounding the bargaining of CO₂ emissions allocation games.     

A bilevel storage pricing model for outbound containers in a dry port system

Serving as a potential solution for seaport congestion and capacity limitation, dry port development is increasingly popular in the freight transport industry. This paper pioneers the research on dry port operations by modelling the storage pricing problem for outbound containers. The interaction between a dry port and multiple shippers is modelled as a bilevel program. The optimal properties of the proposed model under certain conditions are derived analytically, from which a closed-form solution is obtained. Contrary to intuition, the increase of container delivery frequency from shippers may lead to the reduction of dry port’s profit according to model outcomes.     

The analysis and delimitation of Central Business District using network kernel density estimation

Central Business District (CBD) is the core area of urban planning and decision management. The cartographic definition and representation of CBD is of great significance in studying the urban development and its functions. In order to facilitate these processes, the Kernel Density Estimation (KDE) is a very efficient tool as it considers the decay impact of services and allows the enrichment of the information from a very simple input scatter plot to a smooth output density surface. However, most existing methods of density analysis consider geographic events in a homogeneous and isotropic space under Euclidean space representation. Considering the case that the physical movement in the urban environment is usually constrained by a street network, we propose a different method for the delimitation of CBD with network configurations. First, starting from the locations of central activities, a concentration index is presented to visualize the functional urban environment by means of a density surface, which is refined with network distances rather than Euclidean ones. Then considering the specialties of network distance computation problem, an efficient way supported by flow extension simulation is proposed. Taking Shenzhen and Guangzhou, two quite developed cities in China as two case studies, we demonstrate the easy implementation and practicability of our method in delineating CBD.     

Capacity-oriented passenger flow control under uncertain demand: Algorithm development and real-world case study

This paper proposes a problem of passenger flow organization in subway stations under uncertain demand. The existing concepts of station service capacity are extended and further classified into three in different demand scenarios. Mathematical models are put forward to measure the three capacities and a unified simulation-based algorithm is developed to solve them. To increase computing speed, data envelopment analysis (DEA) and genetic algorithms (GA) are embedded in this algorithm. A case study will demonstrate the performance of the proposed algorithm and give a detailed procedure of passenger flow control based on station service capacity in various demand scenarios.     

Incorporating spatial equity into interurban road network design

Methods for the road network design problem, typically, are based on optimization of the network efficiency measures (e.g. network-wide travel time) under a predefined budget. In these approaches, equity issues are not taken into account and, consequently, most of the road improvements are planned next to large cities. Thus, disparities between large and small cities increase, which does not conform to sustainable development objectives. In this paper, to overcome concerns associated with traditional methods, equity is incorporated into the interurban road network design problem. To this end, accessibility concepts are employed. However, unlike previous studies, instead of maximizing the total accessibility, a new definition is proposed for inaccessibility, and total inaccessibility is minimized throughout the network. Using this new definition not only is more compatible with the equity issue, but also helps to eliminate the nonlinearity of the problem. Average travel time to neighboring opportunities is utilized to propose this definition for inaccessibility, which captures the reality more effectively. With the aim of this definition, equity is incorporated into the road network design problem implicitly. This is another improvement over previous methods, where a new term in the objective function or a new constraint is added to include the equity. The proposed model is formulated as a mixed integer linear programming (MILP) problem, where the objective is to minimize the aggregate inaccessibility over all the population centers in the network. To illustrate the application of the model, the Northwest region of the United States is used as the case study. The respective exact solution of the example is found using a commercial solver (CPLEX). This new solution is also compared with the solutions from the traditional methods.     

Risk management in liner ship fleet deployment: A joint chance constrained programming model

This paper provides a tangible methodology to deal with the liner ship fleet deployment problem aiming at minimizing the total cost while maintaining a service level under uncertain container demand. The problem is first formulated as a joint chance constrained programming model, and the sample average approximation method and mixed-integer programming are used to deal with it. Finally, a numerical example of a liner shipping network is carried out to verify the applicability of the proposed model and solution algorithm. It is found that the service level has significant effect on the total cost.     

基于DEA的城市交通可持续发展综合评价研究

从城市交通系统内和各子系统间的投入产出角度出发,结合城市交通系统可持续发展指标体系,给出城市交通系统＂协同＂和＂发展＂有效度的DEA评价模型与方法,进而得到城市交通系统协同发展的DEA综合评价模型.以成都市近6年城市交通系统协同发展作为综合评价的实例进行研究和分析,并给出未来成都市城市交通系统协同发展的对策与建议.     

Global intermodal liner shipping network design

This paper presents a holistic analysis for the network design problem of the intermodal liner shipping system. Existing methods for liner shipping network design mainly deal with port-to-port demand. However, most of the demand has inland origins and/or destinations. Thus, it is necessary to cope with inland origin–destination (OD) pairs involving a change in transport mode from inland transportation to maritime shipping. A method is first proposed to convert inland OD demand to port-to-port demand. Then, a framework for global intermodal liner shipping network design is proposed. Finally, the proposed methodology is applied to and numerically verified by a large-scale network example.