Integration of the cost allocation in the optimization of collaborative bundling

A model is proposed that integrates a cost allocation method – the Shapley value – into the optimization of the synchronized consolidation of transportation orders. By balancing each partner’s delivery date changes (when synchronizing) against its allocated profit, it ensures that the operational plan is acceptable by all partners. In comparison to a model that first plans and then divides the costs, this model limits expensive delivery date changes and does not systematically favor a company with a slightly higher cost of change.     

The effect of high fuel costs on liner service configuration in container shipping

For shipping activities, not least container shipping, bunker fuel is a considerable expense. In the last 5 years, bunker prices have risen considerably. An increasing bunker price in container shipping, especially in the short term, is only partially compensated through surcharges and will therefore affect earnings negatively. This paper deals with the impact of increasing bunker costs on the design of liner services on the Europe–Far East trade. The paper assesses how shipping lines have adapted their liner service schedules (in terms of commercial speed, number of vessels deployed per loop, etc.) to deal with increased bunker costs. The paper also includes a cost model to simulate the impact of bunker cost changes on the operational costs of liner services. The cost model demonstrates for a typical North Europe–East Asia loop that the current bunker prices have a significant impact on the costs per TEU even when using large post-panamax vessels. The model also shows shipping lines are reacting quite late to higher bunker costs. The reasons that explain the late adaptation of liner services relate to inertia, transit time concerns, increasing costs associated with fixing schedule integrity problems and fleet management issues.     

供应链中基于VMI库存与运输协调问题的研究

通过对1个供应商、N个零售商组成的供应链形式的协调问题研究,提出了在VMI系统中协调库存与运输的配送策略。这种配送策略假设需求是Poisson随机过程,以更新理论为基础,基于供应商有权持有小额定单,直到定单数量到达一定程度时进行一起派送,即通过规模经济运输,达到降低成本的目的。     

Bunker consumption optimization methods in shipping: A critical review and extensions

It is crucial nowadays for shipping companies to reduce bunker consumption while maintaining a certain level of shipping service in view of the high bunker price and concerned shipping emissions. After introducing the three bunker consumption optimization contexts: minimization of total operating cost, minimization of emission and collaborative mechanisms between port operators and shipping companies, this paper presents a critical and timely literature review on mathematical solution methods for bunker consumption optimization problems. Several novel bunker consumption optimization methods are subsequently proposed. The applicability, optimality, and efficiency of the existing and newly proposed methods are also analyzed. This paper provides technical guidelines and insights for researchers and practitioners dealing with the bunker consumption issues.     

Probabilistic modeling of freight consolidation by private carriage

A program of freight consolidation is a systematic attempt to decrease total transportation cost between a given origin and destination. Fewer shipments of larger weight are dispatched, while recognizing the inventory carrying cost of holding the first-arriving orders before dispatching the combined load. Here we employ probabilistic modeling to choose the maximum holding time and desired dispatch quantity. We obtain practical decision rules for temporal consolidation for transportation in one's own truck. Final results are expressed visually through a nomograph (four linked graphs) relating decision variables, probability and demand parameters, and objective-function values. The nomograph permits an intuitive sensitivity analysis.     

The potential economic viability of using the Northern Sea Route (NSR) as an alternative route between Asia and Europe

The Arctic Ocean has been greatly affected by climate change. Future predications show an even more drastic reduction of the ice cap which will open new areas for the exploration of natural resources and maritime transportation. Shipping through the Arctic Ocean via the Northern Sea Route (NSR) could save about 40% of the sailing distance from Asia (Yokohama) to Europe (Rotterdam) compared to the traditional route via the Suez Canal. However, a 40% reduction in distance using the NSR does not mean a corresponding 40% in cost savings due to many factors, including: higher building costs for ice-classed ships, non-regularity and slower speeds, navigation difficulties and greater risks, as well as the need for extra ice breaker service.The main purpose of this study is to investigate the economic potential of using the NSR as an alternative route between Asia and Europe by taking all the main factors into consideration. It focuses on economic aspect of the NSR, therefore navigation/ environmental/cultural/legal issues are not discussed.The economic study is conducted by a case study in which 4300 TEU container ships (both non-ice classed and ice classed) are employed to make year round service. The annual profit gained from regular service by a non-ice-classed ship via the Suez Canal for the entire year is compared to the annual profit gained from an ice-classed ship taking the NSR during the navigable months and Suez Canal for the rest of the year. There are three factors that influence the NSR the most: the navigable time of the NSR, Russian NSR fees and bunker prices. To make this study flexible, three scenarios for navigable time, three scenarios for Russian NSR fees as well as three scenarios for bunker prices are proposed. These assumptions are all combined with each other and the profit under each condition is then calculated. The overall comparison is made in order to see under which conditions the NSR is competitive with the Suez Canal.     

Sailing speed optimization for container ships in a liner shipping network

This paper first calibrates the bunker consumption - sailing speed relation for container ships using historical operating data from a global liner shipping company. It proceeds to investigate the optimal sailing speed of container ships on each leg of each ship route in a liner shipping network while considering transshipment and container routing. This problem is formulated as a mixed-integer nonlinear programming model. In view of the convexity, non-negativity, and univariate properties of the bunker consumption function, an efficient outer-approximation method is proposed to obtain an ε-optimal solution with a predetermined optimality tolerance level ε. The proposed model and algorithm is applied to a real case study for a global liner shipping company.     

Comparing strategies for addressing delivery shortages in stochastic demand settings

In logistics networks involving one supply point (depot) and several geographically dispersed demand points (e.g., retail stores), delivery shortages will result if the design of delivery routes ignores random period-to-period fluctuations in customer demands. Delivery shortages may be costly enough for the depot to seek strategies to prevent them. A requirement for rational comparison of strategies is quantifying their effects on total supply chain costs. Accurate distance prediction models are developed to help satisfy this prerequisite for the transportation cost element. These models are integrated into a comparison of strategies on the basis of how these strategies affect inventory and transportation. The focus of findings from the comparison involves identifying the information cost thresholds for accepting/rejecting a demand-responsive strategy. The study's implications for choosing a strategy are presented. ©     

Defining a conceptual model for high-speed vessels

High-speed vessels offer the opportunity for faster and more frequent delivery of smaller quantities of goods over shorter sea crossings. This paper reviews the role of high-speed vessels in the context of the total supply chain based on Fisher's product categorisation model. A mode choice process is presented here within the context of supply chain transport strategies. The model relates mode choice to volume supply, product cost, shipping distance, frequency of service, transit time and product type. The paper concludes that where the flexibility is the market winner high-speed vessels are required whereas where cost is the market winner conventional ships will suffice.     

Fair profit contract for a carrier collaboration framework in a green hub network under soft time-windows: Dual lexicographic max–min approach

This paper models a novel and practical bi-objective hub-location problem under a centralized carrier collaboration framework between one holding company and multiple carriers. The holding company first establishes a hub-and-spoke network in order to locate p hubs and to assign the center nodes to the located hubs. Then, it allocates the transportation routes of the hub network to the carriers. In contrast, the carriers should select an appropriate vehicle type to serve the transportation requests in a green hub network. The carriers are also able to meet the transportation requests within a certain time-window based on a soft time-window mechanism. Moreover, aiming to emphasize green transportation, a vehicle emission model is used to take into account CO₂ emissions of the vehicles where the fuel consumption is a function of speed level. Aiming to identify a win–win deal between the holding company and the carriers, a dual lexicographic max–min (LMM) approach is used in order to optimize their profits in a fair way. Finally, some numerical experiments are presented to demonstrate the applicability of the proposed methodology. The computational results show that not only the holding company and the carriers can better generate a fair profit contract among themselves using the LMM approach, but also both can obtain more profit in the worst case for their businesses rather than using the max–min approach. In addition, sensitivity analyses show that increasing the size of the soft time-window leads to a reduction in the delivery schedule violations, while results in raising the total profit. Moreover, the tax cost of fuel consumption as well as the number of potential vehicles has a substantial impact on both the fuel consumption and carrier’s profit.     

Integrating the warehousing and transportation functions of the supply chain

Electronic commerce and associated business-to-business transaction capabilities have changed the way in which supply chains operate. The Internet has enabled information exchange on an unprecedented scale, often at a pace too fast for normal consumption. Companies are not equipped to make effective use of data from warehouse management systems––which contain information on supplier/customer warehouse inventory levels and key customer ordering patterns––and transportation management systems––within which information pertaining to the location of important supply chain assets such as products or vehicles is typically stored. These systems are key factors in integrating the physical flow of goods along the supply chain. The integration of these systems leads to global inventory visibility, which, in turn, leads to reduced costs and improved customer service by decreasing shipping and receiving cycle times, increasing shipment and inventory accuracy, and decreasing lead-time variability. This paper examines the total cost benefits that can be achieved by suppliers and warehouses through the increased global visibility provided by an integrated system. We develop a discrete event simulation model of a multi-product supply chain to examine the potential benefits to be gained from global inventory visibility and trailer yard dispatching and sequencing techniques. Experimental results demonstrate the potential for this integrated paradigm to improve customer service through improved efficiencies, reduced costs, and reduced lead-time variability.     

Food quality and the circulation time of commodities: lessons from the British milk trade 1845–1914

The major resurgence of transport geography over the last two decades has provided us with important insights and knowledge on the spatial aspects of transportation under global capitalism. In spite of its substantial progress, however, the sub-disciple has tended to study the movement of goods in abstraction from their physical properties and to conceptualize commodities as fixed and unchanging. Although this assumption is a reasonable one for a great many commodities, it is less so for more perishable goods, especially food. In an attempt to develop this insight further, this article argues that transport geography needs to pay more attention to the relationship between space–time processes and the physical properties of goods in transit. I investigate this relationship through a study of the development and social impacts of the milk trade in Britain c.1845–1914.     

An stated preference analysis of Spanish freight forwarders modal choice on the south-west Europe Motorway of the Sea

This paper aims to contribute towards the design of effective freight transport policy by means of empirical analysis. In order to do so, a stated preference survey is undertaken to model the modal choice between door-to-door road transport and short sea shipping in the Motorway of the Sea of south-west Europe. The proposed analysis will provide policymakers with the necessary tool to identify the critical areas that should be addressed by future policy action in order to boost short sea shipping on Spain's Mediterranean coast. By applying the proposed method, we will be able to obtain estimates of the subjective values of transport attributes – value of time, value of reliability and value of frequency – in freight transport, values for which barely any empirical evidence on a national scale exists. Quantifying such values is a key part of the cost benefit analyses performed when evaluating transport projects.     

铁路空车调整综合优化模型

随着铁路运输的发展,货物车辆供给不足的问题日益突出。为在路网上合理调拨空车,根据空车走行费用(含中转费用),以及空车过早(或过晚)到达需求站而产生的额外管理费(或推迟运输的延误费)之和最小的原则,同时考虑线路的通过能力,建立了铁路空车调整综合优化模型,并用LINGO语言对模型进行了求解。     

运输系统生态可持续性评价指标体系的研究

通过对运输系统生态经济指标分析,将各种运输方式对土地占用、能源消耗、客运和货运周转量、污染物排放、环境危害、安全、便捷性等方面的影响进行比较,并应用灰色关联分析方法进行综合评价。综合评价结果表明:公路运输的便捷性最强,航空运输在中长距离的时效性最强,水运在成本与效益分析中最经济,铁路在占地、能源消耗、污染物排放等生态性指标方面有较突出的优势。     

Multi-level inventory management decisions with transportation cost consideration

In this article we address specific inventory management decisions with transportation cost consideration in a multi-level environment consisting of a supplier–warehouse–retailers. We develop two models – namely, decentralized ordering model and centralized ordering model to investigate the effect of collective ordering by retailers on the total inventory cost of the system. A numerical study shows that the proposed model is robust and generates reasonable cost savings. The models have potential in several multi-level applications such as fresh or frozen food delivery to stores of different supermarkets or the supply of medicine to a number of hospitals from a wholesaler.     

Towards enhancing the last-mile delivery: An effective crowd-tasking model with scalable solutions

In urban logistics, the last-mile delivery from the warehouse to the consumer’s home has become more and more challenging with the continuous growth of E-commerce. It requires elaborate planning and scheduling to minimize the global traveling cost, but often results in unattended delivery as most consumers are away from home. In this paper, we propose an effective large-scale mobile crowd-tasking model in which a large pool of citizen workers are used to perform the last-mile delivery. To efficiently solve the model, we formulate it as a network min-cost flow problem and propose various pruning techniques that can dramatically reduce the network size. Comprehensive experiments were conducted with Singapore and Beijing datasets. The results show that our solution can support real-time delivery optimization in the large-scale mobile crowd-sourcing problem.     

How did COVID-19 impact air transportation? A first peek through the lens of complex networks

The current outbreak of COVID-19 is an unprecedented event in air transportation. This is probably the first time that global aviation contributed to the planet-wide spread of a pandemic, with casualties in over two hundred countries. As of August 23rd, 2020, the number of infected cases has topped 23 million, reportedly relating to more than 800,000 deaths worldwide. However, there is also a second side of the pandemic: it has led to an unmatched singularity in the global air transportation system. In what could be considered a highly uncoordinated, almost chaotic manner, countries have closed their borders, and people are reluctant/unable to travel due to country-specific lock-down measures. Accordingly, aviation is one of the industries that has been suffering most due to the consequences of the pandemic outbreak, despite probably being one of its largest initial drivers. In this study, we investigate the impact of COVID-19 on global air transportation at different scales, ranging from worldwide airport networks where airports are nodes and links between airports exist when direct flights exist, to international country networks where countries are contracted as nodes, and to domestic airport networks for representative countries/regions. We focus on the spatial-temporal evolutionary dynamics of COVID-19 in air transportation networks. Our study provides a comprehensive empirical analysis on the impact of the COVID-19 pandemic on aviation from a complex system perspective using network science tools.     

铁路运输在物流成本中的经济性分析

肯定物流在社会经济生活中的重要性,指出运输环节在降低物流成本、减少社会资源耗费中的突出地位,列举铁路运输方式的经济比较优势,分析铁路运输成本在经济学意义上的价值构成和含义,以及运输成本的计算、构成和与产品的联系等特点,得出降低铁路运输成本的主要途径是强化科学管理、优化运输组织的结论,并据此提出均衡运输、合理运输、直达运输、集中化运输、重载和高速运输等经济性方法。     

The rationale behind and effects of Bunker Adjustment Factors

The Bunker Adjustment Factor (BAF) system was first introduced following the oil shocks of the 1970s. The underlying justification for such a system was that shipping lines operating in freight conferences could not otherwise adjust their prices promptly enough to counteract the devastating effect of bunker price increases. Thirty years after its imposition, BAF has always been a bone of contention between carriers and shippers. Ocean carriers contend that it is a necessary evil to reduce their exposure to volatile bunker price, while shippers argue that this risk should either be considered as a normal commercial venture, or dealt with in a more transparent way. When bunker surcharges began to climb in 2003, BAF disputes became one of the main obstacles to the dialog between both parties. To settle the dispute over BAF, the Europe Commission (EC) called for the submission on the issue of surcharges.The European Commission banned carrier conferences on October 17th 2008. The shipping lines now set their own independent BAF rates, which are closely monitored by the EC to ensure no collusion. The fluctuation in oil price in 2008 means that the BAF rates are now coming down, but there are still some wide variations in application. During this period of dramatic change in shipping environment, it has become important to provide a theoretical framework for analyzing the BAF. This paper focuses on examining the rationale behind and effects of BAF. A microeconomic model is made to explore the underlying mechanism of BAF. By examining the trade routes of Asia to Europe and Asia to North America during the period 2003-2008, this study finds the practice of BAF cushions an ocean carrier from the negative effects of bunker price fluctuations, and provides shipping lines a powerful tool to change the incentive structure facing carriers. Despite engineers showing that reducing the speed of vessels can economize fuel consumption evidence shows there has been little change by major shipping lines in their transit time and sailing schedules during the recent period of skyrocketing fuel price. It is apparent they use the BAF as the cushion against the effect of rising bunker prices.