Transportation Research Part A: Policy and Practice (09658564)165pp. 144-171
We investigate pricing competition between passenger transportation modes in a transportation market by using a game-theoretic approach. Airplane and intercity bus operators are considered as incumbent; while a High-Speed Rail (HSR) operator decides on whether or not to enter the market. If the incumbent operators evaluate the entrance threat of HSR as serious, they have two alternatives: a barrier pricing strategy (BPS) to deter its entrance, and an accommodation pricing strategy (APS). Their interaction involves two competitive and cooperative aspects, called the coopetition interaction. Moreover, we extend the analysis to a real-world situation in which a government, as a social welfare maximizer, intends to certify and support one operator out of two candidate HSR operators. Our analyses reveal that: (a) the passengers’ heterogeneity (with respect to their perceptions on the operators’ quality of services) is the main driver for pricing competition between the three operators. (b) Under certain conditions, implementing a BPS is not only precluded for the incumbent operators, but also their pricing strategies cannot even guarantee their survival in the market. To address this issue, we suggest the incumbent operators adopt non-pricing strategies. Nevertheless, an incumbent operator may freely ride on the other ones’ non-pricing strategy. (c) Under a short-term (long-term) planning horizon, the government should specifically concentrate on compensating for the HSR operating cost (procurement cost of rolling stock). (d) In contrast to the short run, government expenses and the HSR's profit exploitation provide a strong foundation for the passengers’ full satisfaction in the long run. © 2022 Elsevier Ltd
Environmental Science and Pollution Research (09441344)29(25)pp. 37748-37764
In recent years, suppliers in developing countries face the challenge of their low technological and knowledge-related capabilities to enhance sustainability. In addition, buying firms cannot optimize the performance of the whole supply chain because the supplier sustainability practices are unobservable to them and to the public. These two challenges lead to the occurrence of several environmental and social scandals. These scandals pose serious economic and reputational consequences to supply chain members, especially buying firms. Given these challenges and using a sequential game-theoretic methodology, our contribution to the literature on supplier sustainability is to address the effects of supplier code of conduct (SCC) programs on different performance indicators of supply chains. Our analyses indicated that (a) an SCC program can mitigate the supply chain performance deficiencies created by the lack of the integrated optimization of the whole supply chain. Moreover, an SCC program can be superior to some common auditing programs initiated by buying firms. (b) In cases that the supplier’s capability is low or moderate, an SCC program provides a Pareto improvement in its sustainability level and the buying firm’s profit. (c) High consumer awareness threatens the buying firm’s survival in the market. Given this threat, an SCC program indirectly enhances the buying firm’s potential to survive. (d) Buying firms should lower their suppliers’ wholesale prices in exchange for a substantial investment in their suppliers’ capabilities, irrespective of whether or not an SCC program is initiated. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Transportation Research Part B: Methodological (01912615)153pp. 272-295
Sustainable freight transportation is a logistics approach that provides affordable services to consumers where environmental, economic, and social sustainability dimensions are concerned. Governments usually improve sustainability dimensions in freight transportation by imposing taxes on transportation systems. Therefore, they should extend their knowledge on interactions between sustainability dimensions and how their interventions affect each dimension. In this regard, we analyze competition between two freight transportation systems in the context of government intervention. These systems include road and intermodal road–rail transportation modes, where the latter is regarded as an environmentally sustainable mode. A sequential game is addressed to analyze the duopoly competition. In the upper level, a government, as a Stackelberg leader, imposes taxes on fuel usage based on environmental, economic, and social concerns. In the lower level, a Nash game is developed to analyze price competition in the transportation market. Our analyses reveal that: (a) Given a fixed level of the consumers' loyalty to their specific transportation systems, economic and social sustainability are consistent with each other, while they conflict with environmental sustainability. (b) Economic risks increase economic sustainability requested by the transportation systems. Such a relationship and the mentioned conflict between environmental and economic sustainability imply that a reduction of economic risks by the government indirectly contributes to environmental sustainability. (c) An increase in the consumers' loyalty simultaneously improves the three sustainability dimensions. (d) The energy efficiency improvements of the transportation systems may pose adverse environmental and social effects, called the rebound effects. Moreover, government intervention effectively eliminates such rebound effects. (e) Government support for the service enhancement of the intermodal system, combined with the national advertisement of this system, may exempt the government from subsidy payment. © 2021 Elsevier Ltd
Networks and Spatial Economics (1566113X)21(1)pp. 123-173
This article studies a competitive freight transportation pricing problem in the presence of two Intermodal Service Providers (ISPs) and a Direct Transportation System (DTS). The ISPs apply both rail and road transportation modes to carry the demands of a network of customers. The DTS uses only roads to carry the demands, without any transhipment at a distribution center. Each customer chooses its best transportation service based on the prices offered by the ISPs and the expenses of using the DTS. The ISPs determine their prices to maximize their profits, considering the customers’ choice behaviour. In order to determine the equilibrium decisions, a non-cooperative game-theoretic approach based on Stackelberg leader-follower competition is applied. Mixed-integer linear programming models are proposed to formulate this competition. A real-life case study is also conducted to demonstrate the validity of the models. We find that a barrier pricing strategy from the leader to deter the entrance of the follower ISP is not recommended for both of them because it may even lead to a negative value of profits for the leader. Finally, some sustainability objectives of the government, as the strategic decision maker, are examined. The results could help the government assess the effects of its policies on the transportation market, the environment, and the society. © 2021, Springer Science+Business Media, LLC, part of Springer Nature.
International Journal of Industrial Engineering Computations (19232934)12(3)pp. 249-272
Optimizing the trade-off between crucial decisions has been a prominent issue to help decision-makers for synchronizing the production scheduling and distribution planning in supply chain management. In this article, a bi-objective integrated scheduling problem of production and distribution is addressed in a production environment with identical parallel machines. Besides, two objective functions are considered as measures for customer satisfaction and reduction of the manufacturer’s costs. The first objective is considered aiming at minimizing the total weighted tardiness and total operation time. The second objective is considered aiming at minimizing the total cost of the company’s reputational damage due to the number of tardy orders, total earliness penalty, and total batch delivery costs. First, a mathematical programming model is developed for the problem. Then, two well-known meta-heuristic algorithms are designed to spot near-optimal solutions since the problem is strongly NP-hard. A multi-objective particle swarm optimization (MOPSO) is designed using a mutation function, followed by a non-dominated sorting genetic algorithm (NSGA-II) with a one-point crossover operator and a heuristic mutation operator. The experiments on MOPSO and NSGA-II are carried out on small, medium, and large scale problems. Moreover, the performance of the two algorithms is compared according to some comparing criteria. The computational results reveal that the NSGA-II performs highly better than the MOPSO algorithm in small scale problems. In the case of medium and large scale problems, the efficiency of the MOPSO algorithm was significantly improved. Nevertheless, the NSGA-II performs robustly in the most important criteria. © 2021 by the authors; licensee Growing Science, Canada.
Journal of Environmental Management (10958630)254
Responsible sourcing refers to the compliance of suppliers with environmental and social standards. In today's supply chains, buyers and external stakeholders use auditing mechanisms to induce responsible sourcing. For the first time, this paper investigates the effect of a buyer's audits on the tactical decisions of supply chains. We address a repeated game with one buyer and one critical supplier. At the strategic stage, the buyer chooses the optimal auditing efforts to induce responsible sourcing. At the tactical stages, the buyer and supplier compete with each other for their profit margins, while the buyer also determines the quantity of production. Moreover, the supplier chooses between responsible and irresponsible production. Two auditing mechanisms are defined for the buyer: strong incentive compatibility (SIC) and weak incentive compatibility (WIC). The effectiveness and backfiring conditions for these auditing mechanisms are identified. The former denotes that the mechanism can induce responsible sourcing, while the latter denotes the conflict between supply chain transparency and responsible sourcing. The results show that the supplier requires an efficiency wage for compliance with responsible sourcing standards. We find that auditing mechanisms in supply chains face an unintended consequence. Higher auditing efforts by the buyer reduce the supplier's wholesale price. This reduction may offset the greater potential for discovery obtained by higher auditing efforts. We also show that the effect of consumer awareness on responsible sourcing is not straightforward and depends strongly on the buyer's auditing mechanism. If the buyer chooses the SIC (WIC) auditing mechanism, consumer awareness always favors (threatens) responsible sourcing. Finally, this research suggests that coordination between buyers and external stakeholders contributes greatly to responsible sourcing. © 2019 Elsevier Ltd
Neural Computing And Applications (09410643)31(12)pp. 9073-9093
In this study, a bi-objective optimization problem for a supply chain with different transportation modes is addressed. The first objective function is minimizing costs imposed by production, batching, due date assignment and transportation. The second one is minimizing inventory and tardiness costs. Also, a heuristic rule is developed to choose non-dominated transportation modes. Three metaheuristic algorithms including multi-objective particle swarm optimization (MOPSO), non-dominated sorting genetic algorithm (NSGA-II) and hybrid NSGA-II (HNSGA-II) are customized to solve the problem. In addition, a theoretical improvement in the non-dominated sorting procedure called improved efficient non-dominated sorting (IENS) is proposed. Computational tests are used for comparing and evaluating the proposed methods and algorithms. The results show that IENS reduces running time compared to the modern method of non-dominated sorting, the efficient non-dominated sorting method, and this reduction is statistically significant. Also, the HNSGA-II has an average but robust performance compared to the other two algorithms. © 2018, Springer-Verlag London Ltd., part of Springer Nature.
