Minimizing greenhouse gas emissions in intermodal freight transport: an application to rail service design

Freight transport has undesirable effects on the environment. The most prominent of these is greenhouse gas emissions. Intermodal freight transport, where freight is shipped from origin to destination by a sequence of at least two transportation modes, offers the possibility of shifting freight (either partially or in full) from one mode to another in the hope of reducing the greenhouse emissions by appropriately scheduling the services and routing the freight. Traditional planning methods for scheduling services in an intermodal transportation network usually focus on minimizing travel or time-related costs of transport. This article breaks away from such an approach by addressing the issue of incorporating environment-related costs (greenhouse gases, to be specific) into freight transportation planning and proposes an integer program in the form of a linear cost, multicommodity, capacitated network design formulation that minimizes the amount of greenhouse gas emissions of transportation activities. Computational results based on an application of the proposed approach on a real-life rail freight transportation network are presented.     

Real-time control of freight forwarder transportation networks by integrating multimodal transport chains

Western European freight forwarders are continually being forced to increase the efficiency of their transportation processes because of the liberalization and deregulation of the European transport market. This paper proposes a new real-time-oriented control approach in order to expand load consolidation, reduce empty vehicle trips, and handle dynamic disturbances. This approach integrates multimodal transportation and multiple transshipments for the first time. Thus, it enables the flexible generation and adaptation of transportation processes. In order to be able to handle occurring disturbances, an optimization procedure that adapts the transportation processes is continually applied. Vehicle breakdowns or deceleration of vehicles, traffic congestion, and street blockages are integrated as possible disturbance scenarios. At the same time, dynamically incoming transportation requests are also dealt with. Moreover, cooperative agreements between freight forwarders, which are gaining increasing importance, are integrated by mapping hubs and external services. The efficiency of the new real-time approach is validated by several computational experiments. In particular, the use of the entire execution time for plan adaptation as well as the integration of multiple transshipments has shown promising results.     

The multiple frequency delivery operations in the time-definite delivery industry

The pure hub-and-spoke network is an efficient network structure for time-definite freight delivery common carriers. Centres perform pickup and delivery functions, while hubs consolidate partial loads. This substantially reduces the transportation costs with only a small increase in the handling cost. In Taiwan, as well as in the US, carriers run their delivery operations once a day. As a result, the feeder fleet is under-utilized. This research studied the impact of multiple frequency delivery operations on the feeder fleet size. We formulated line-haul operations planning for multiple frequency delivery operations as an integer programme. We developed an α-optimal implicit enumeration algorithm and used two small networks from the third largest carrier in Taiwan for numerical testing. The results demonstrated a smaller feeder fleet size compared with the single frequency delivery operations.     

A review of recent research on green road freight transportation

Road freight transportation is a major contributor to carbon dioxide equivalent emissions. Reducing these emissions in transportation route planning requires an understanding of vehicle emission models and their inclusion into the existing optimization methods. This paper provides a review of recent research on green road freight transportation.     

Designing new European rail freight services

We present an optimization model for design of transportation services, with a particular emphasis on how attention to service quality affects the design. The model is applied to a real-world case study where opportunities for new rail-based freight transportation services are explored. Fleet sizing is introduced to the service network design, because cost of acquiring locomotives is high, and inefficient resource utilization could result if fleet sizing is carried out a posteriori. The problem is a cross-border planning problem, introducing need for change of locomotives at borders, and separate fleets of locomotives thus have to be modelled. Demand in the system is characterized by various commodity groups with different service quality requirements. We propose a mixed integer programming model with a nonlinear objective function. The model finds the most profitable operations for the train operator when important service quality factors are accounted for.     

基于不确定理论的铁路货运需求预测

合理预测铁路货运需求是铁路管理部门建设、运营等决策基础。为应对铁路货运需求的复杂变化,基于Pearson相关性分析方法筛选出铁路货运需求的七个具有关键影响的因素,并结合不确定理论建立不确定多元线性回归模型,相应的铁路货运预测结果由传统单一值变成可能的需求区间范围,更加符合处于不确定环境下的铁路货运需求实际情况。选取国家统计局2004~2016年相关数据进实证研究,并与回归模型以及BP模型的预测结果对比分析,实验表明不确定多元线性回归的预测结果更加精确。     

The information value of logistics platforms in a freight matching market

The information asymmetry in the freight matching of the long-haul trucking industry usually pushes shippers to join a logistics platform that has better knowledge of truckers’ cost information. A logistics platform that is plugged into a freight transportation system helps shippers overcome their information disadvantage but produces the double marginalization effect. We investigate the equilibrium characteristics of a shipper and logistics platform in the freight matching market and find that the shipper prefers to cooperate with the logistics platform in a small-scale sales market but searches for truckers by himself in a large-scale sales market. We show that the information value of a logistics platform for the freight system consists of two aspects: (i) employ low-cost truckers for the shipper and avoid the shipper’s inefficient expansion of the selling quantity in a moderate-scale sales market with greatly heterogeneous truckers, and (ii) improve both the total profit and social welfare of the freight system in a small-scale sales market. We further find that the shipper’s private information may hurt the logistics platform and the logistics platform can mitigate her double marginalization disadvantage by improving value-added services or lowering the logistics price in a large-scale market. Our findings provide guidelines for the shipper and logistics platform on how to choose the appropriate transportation strategy and employment strategy in different logistics markets.     

主导权异质性视角下的过坝方式货运量分担率研究

翻坝公路与通航建筑物两类过坝方式的主导权,分别由货主和通航管理局所主导。针对货物过坝主导方的异质性,首先建立了各过坝方式的效用函数来分析主导权的转移机制。然后据此结合通航建筑物过坝原则,构建了货运量分担率多目标优化模型。最后以三峡工程为例,探讨了翻坝运输费率和船舶过坝顺序对分担率的影响,进而探讨了缓解大坝通航拥堵的决策机制。结果表明:提高翻坝公路的货运分担,可以有效改善船舶及货物的过坝运输状况;相比翻坝运输费率,降低装卸费率能更有效地提高翻坝公路货运分担水平;船舶过坝存在一个次序区间,使得水运货物经由通航建筑物过坝和经由翻坝公路过坝的效用相同。     

快递企业航空货运网络的构建

快递业竞争激烈,构建高效合理的航空货运网络是快递企业提高竞争力的重要手段。“枢纽—辐射”式航空货运网络是整合航空快递资源、提高航空快递资源利用效率、提高快递企业竞争力的有效模式。本文以降低航空快递网络成本、加快航空快递处理时间为目标,从航空快递网络枢纽的选取、指派关系的确定、枢纽个数的选择三个方面研究了航空快递网络模型建立问题,选用遗传算法求解不同枢纽个数下航空快递网络的运输成本,并据此进行枢纽的选取,运用重力模型法进行指派关系的确定,在此基础上运用超效率DEA模型确定枢纽个数。接着,以包含17个节点的顺丰航空快递网络的规划为例,对本文所提出的模型和算法进行了验证,验证结果证实了模型的合理性。本文的研究为快递企业构建航空货运网络提供了科学实用的方法,该方法的使用可以降低航空货运成本,提高效率,从而提高快递企业的竞争力。     

Operational transportation planning of freight forwarding companies in horizontal coalitions

In order to improve profitability, freight forwarding companies try to organize their operational transportation planning systematically, considering not only their own fleet but also external resources. Such external resources include vehicles from closely related subcontractors in vertical cooperations, autonomous common carriers on the transportation market, and cooperating partners in horizontal coalitions. In this paper, the transportation planning process of forwarders is studied and the benefit of including external resources is analyzed. By introducing subcontracting, the conventional routing of own vehicles is extended to an integrated operational transportation planning, which simultaneously constructs fulfillment plans with overall lowest costs using the own fleet and subcontractors’ vehicles. This is then combined with planning strategies, which intend to increase the profitability by exchanging requests among members in horizontal coalitions. Computational results show considerable cost reductions using the proposed planning approach.     

基于分解—集成的铁路货运需求预测研究

铁路货运量受到多种因素影响,准确的预测可以为铁路行业未来规划的编制提供重要的参考依据,也可以使铁路部门制定符合当前货运市场的运输政策。货运量数据具有非线性、不平稳的特点,利用传统的单一预测模型进行预测,很难描述整体特征,预测精度有待提高。本文基于分解—集成的原则,利用变分模态分解算法将货运量分解为高频和低频模态,针对各模态特点,分别建立预测模型,将得到的预测结果加总起来作为最终货运量的预测值。实证表明,分解—集成预测方法与传统的单一预测模型相比,提高了预测的准确率,可以很好地应用在铁路货运量需求预测的研究中。     

基于公路运力信用结构的供应链金融授信分析

文章首先从信用入手,分析供应链金融增信的要素,剖析公路运力信用结构组成,构建主体信用、交易信用及监管信用的具体指标,并明确三者与供应链金融授信额度的关系。其次,以融资自偿为基础,通过分析公路运力成本的构成及统计数据,确定出授信比率的基础值以及监管信用对基础值的影响。通过物流企业货量服从正态分布的特征,模拟出公路运力运费收入以及交易信用对运费收入的影响。最后,结合两者构建出受主体信用现金流约束检验的授信额度模型,并就金融机构风险偏好为风险规避的情况进行了算例分析。     

Multimodal freight transportation planning: A literature review

Multimodal transportation offers an advanced platform for more efficient, reliable, flexible, and sustainable freight transportation. Planning such a complicated system provides interesting areas in Operations Research. This paper presents a structured overview of the multimodal transportation literature from 2005 onward. We focus on the traditional strategic, tactical, and operational levels of planning, where we present the relevant models and their developed solution techniques. We conclude our review paper with an outlook to future research directions.     

集装箱货运站选址的模糊聚类模型与算法

论分析了集装箱运输的过程，提出集装箱运输是建立在与集装箱箱型相适应的，且具有相同作业能力的一定数量的集装箱货运站基础上的规模运输的发展思想；利用模糊聚类分析方法，研究了集装箱货运站选址的模糊聚类模型与算法；选择全国236个地级及以上城市，探讨了集装箱货运站建设的可能等级、数量和地址。     

A general system theory approach to rail freight car fleet sizing

The transportation of goods from shippers to consignees is a railroad's major activity. Rail freight cars are enormously expensive and a rail vehicle fleet represents one of the largest capital resources of most railroads. Resource allocation to rail freight cars is an extraordinary complex managerial problem. This paper describes the determination of an optimal number of rail freight cars so as to satisfy the demand, on one hand, and minimize the total cost, on the other. A new mathematical model relying on optimal control theory is developed. The problem is formulated as the problem of finding an optimal regulator for a linear system, excited by Gaussian white noise, a quadratic performance index, and random initial conditions. The model has been tested on numerical examples.     

Time Charters with Purchase Options in Shipping: Valuation and Risk Management

Abstract

The article studies the valuation and optimal management of Time Charters with Purchase Options (T/C–POPs), which is a specific type of asset lease with embedded options that is common in shipping markets. T/C–POPs are economically significant and sometimes account for more than half of the stock market value of listed shipping companies.

The main source of risk in markets for maritime transportation is the freight rate, and we therefore specify a single-factor continuous time model for the dynamic evolution of freight rates that allows us to price a wide variety of freight rate-related derivatives including various forms of T/C–POPs using contingent claims valuation techniques. Our model allows for the derivation of closed valuation formulas for some simple freight rate derivatives, whereas the more complex ones are analysed using numerical (finite difference) procedures. We accompany our theoretical results with illustrative numerical examples as we proceed.     

危险品运输安全-效益优化决策研究

对危险品运输安全-效益优化问题进行了研究,基于委托-代理理论,建立了在委托人对运输安全具有完全明辨性的进度激励-安全控制决策的博弈模型,分析了双方实现各自利益最大化的最优策略,即委托人确定合理的危险品提前运达效益的分配系数、运输安全保证率水平及委托人对运输各环节安全的检测水平,以及承运人在上述条件下,确定合理的进度加快投入的努力与安全控制的水平,进而可为危险品运输委托人与承运人之间的最优运费确定提供依据;文章的最后进行实例应用分析.     

基于运输问题悖论的最大运量问题以及运价合理性的研究

该文提出了判断运输问题悖论是否存在的对偶规划条件以及目标函数差值模型,并针对运输悖论中存在的两个颇有实际意义的问题:增加运量而总运费不增的最大调整量问题以及产销地的单位运价不合理问题,给出了用以获得最大运量调整方案的最大供需量模型以及通过改变不合理运价来消除悖论的合理定价法,并辅以实例加以验证。     

Horizontal cooperation among freight carriers: request allocation and profit sharing

In modern transportation systems, the potential for further decreasing the costs of fulfilling customer requests is severely limited while market competition is constantly reducing revenues. However, increased competitiveness through cost reductions can be achieved if freight carriers cooperate in order to balance their request portfolios. Participation in such coalitions can benefit the entire coalition, as well as each participant individually, thus reinforcing the market position of the partners. The work presented in this paper uniquely combines features of routing and scheduling problems and of cooperative game theory. In the first part, the profit margins resulting from horizontal cooperation among freight carriers are analysed. It is assumed that the structure of customer requests corresponds to that of a pickup and delivery problem with time windows for each freight carrier. In the second part, the possibilities of sharing these profit margins fairly among the partners are discussed. The Shapley value can be used to determine a fair allocation. Numerical results for real-life and artificial instances are presented.     

An Empirical Evaluation of Investigating Transportation Mode Attributes for Commodities

A number of transportation demand models have been formulated using the abstract mode concept. Unfortunately, most of these models use a priori economic theory to derive the variables used in the analysis. This study describes an empirical approach for the specification of mode attributes used by purchasers of transportation modes for the movement of commodities. Results reported from a study conducted on the Montreal-Toronto corridor in Canada suggest that a number of important variables have been neglected in models of carrier selection for freight.