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.     

多态不确定环境下生产与运输方案的优化方法

研究了一类生产运输问题的优化模型,其中产地可供应量、机器可使用最大时间为模糊参数,市场需求和生产单位产品时间随机参数,在产地可供应量,市场需求,预算,产地机器可运转时间,目的地库存空间等约束下,该模型同时优化了生产运输的总成本和运输时间.基于修正后的S型曲线隶属函数和机会约束规划方法,推导了原模型的确定型等价式,并据此设计了寻求满意生产与运输方案的交互式算法。     

循环取货模式下的多车场协同运输问题研究

分析循环取货模式和协同运输问题的关联性,提出了供需节点分离下的多车场一体化协同运输路线优化问题,考虑运输价值和运输成本,引入节点-弧流量的概念,通过比较流量大小确定节点集合,构建了问题的多供应点、多需求点运输模型.考虑取货的单向性和送货的闭合性,构造了求解模型的两阶段算法,运用动态规划的递推解法确定取货最优路线,然后基于余弦定理的几何法求解出发点和返回点不相同的送货路径优化问题,最后通过算例分析,说明了模型的合理性和算法的有效性.     

基于改进VIKOR方法的地震应急物资运输决策问题研究

地震灾害应急救援物资方案的合理选择对与减少人员伤亡,降低灾民的财产损失具有重要影响。本文针对属性权重未知情形下的地震应急物资运输方案决策问题,提出了一种Pythagorean模糊不确定语言与前景理论相结合的改进VIKOR决策方法,即PFUL-PT-VIKOR法。首先,采用Pythagorean模糊不确定语言用于描述和融合专家对地震应急物资运输方案在考虑多种属性影响下的感知信息;其次,利用主客观融合法对属性权重进行求解;然后,提出基于前景理论的改进VIKOR法并得出方案排序;最后,通过算例分析,对所提出方法的有效性和实践性给予验证。结果表明,PFUL-PT-VIKOR模型有助于增强决策专家对不确定突发情景信息感知的知识表示能力,解决属性赋权过于主观或过分依赖样本的困难,并突围了应急决策者隐性心理行为较难定量应用的思维定势,增强了模型的现实适用性,为地震应急物资是否合理运输提供决策支持。     

汽车租赁调度中基于经济效益的目标优化模型的应用

本文针对一家汽车租赁公司,利用运输规划模型,将汽车的总需求量和总拥有量的关系看成产销平衡或产销不平衡的运输问题,得到在一定条件下每天的转运车辆数和最小成本.接着根据转运成本和短缺损失总和最小的目标,确定最优调度方案.     

快餐连锁店的行车路线模型

本文针对香港最大的快餐连锁店之一－－大家乐快餐店－－的运输路线问题，提出了切实可行的决策支持模型。大家乐快餐店于1975年在香港开业。经过20年快速稳定的发展，目前已拥有大约100个分店遍布香港各地，并且仍在以每年10个分店的速度发展。该店用一支小规模的卡车队将大量的物品运到各分店，为了降低运输费用，加快运输速度，快餐店的物资分配部门的经理面临着如何为公司提供经济有效的运输服务这一挑战性任务。我们的研究有两个目标。一是开发一个制定行车路线的算法，以帮助路线设计者设计行车路线，它不仅要节约费用，还要提高效率。另一目标是为运输经理提供指导以决定是将货物从快餐总店运到各分店，还是从供应商直接运到各分店。为此我们用试探法来确定行车线路表。新开发的决策支持系统允许用户更新各分店的有关信息，诸如停车的限制等。该系统提供的行车线路不但节约了开支，而且减少了运输时间。     

随机需求条件下的延迟发运策略模型及性质

本针对随机需求条件下物流配送中心的库存和运输联合决策问题，在基本库存和自身运输能力不足的情况下，提出对剩余客户订货需求采取部分延迟到下一期与部分利用第三方物流立即发运两相结合的策略，并在具有一般惩罚(损失)费延迟发运量限制的条件下，建立运输和库存相关总成本数学期望最小的优化模型，论证了该模型的主要性质，在此基础上很容易构造求解该类问题的优化方法。     

路径既定条件下有害物品运输策略选择研究

对有害物品运输问题的研究,大多集中在考虑路径风险情形下的路径选择问题方面,对路径既定条件下运输策略的选择问题尚未涉及.利用概率分析方法,比较了路径既定条件下一定量有害物品选择一次运输策略和选择多次运输策略在发生事故的可能性、路径风险两方面的差异.结果发现,一次运输情形下,发生事故的可能性较小,路径风险也较小,要使可能损失赔偿与运输成本之和最小,决策者应尽可能选择大载重量运输车辆进行有害物品运输.     

单一生产商单一零售商供应链中最优生产与运输协调策略研究

在供应链背景下,易腐品的生产运输协调决策具有非常重要的现实意义,也是近几年研究的热点问题。本文在前人研究的基础上,通过引入安全库存并将其作为决策变量,拓展了易腐品生产运输协调决策模型;并证明了最佳运输批量序列一定是单调不减的及第一次补货时一定要清空库存;进而证明了最佳运输批量序列的具体形式并提出了一种运输策略。本文的目标是在新的运输策略下最大化单一生产商单一零售商供应链系统的利润,找到最佳运输批量、最佳生产时间以及运输次数。最后,本文进行了算例分析,用来验证本文提出的模型。     

工件的运输和继列分批加工协作排序问题

近年来,工件的运输和加工协作排序问题在物流和供应链管理领域得到广泛关注. 讨论了先用 $\ m$ 台车辆将工件从等待区域运输到继列分批处理机处, 再进行分批加工的协作排序问题, 加工一批工件需要支付一定的费用, 目标为最小化工件的总完工时间与批的加工费用之和. 在工件的加工时间都相等的情况下, 如果工件运输方案确定, 给出了多项式时间的动态规划算法; 如果工件运输方案不确定, 证明了该问题是{\, NP}-难的, 给出了车辆返回时间 $\ t=0$ 时, 最差性能比等于 $\ 2-\frac{1}{m}$ 的近似算法.     

An integrated producer–buyer supply chain with delivery cost under stochastic transportation time

An integrated producer–buyer supply chain is used to simultaneously determine the optimum levels of the safety stock, delivery quantity, and number of shipments in this paper. The scenario is created by scheduling a single-setup at the producer with multiple deliveries to the buyer, and all shipments to the buyer are equal-sized batches. This study attempts to study the effects of delivery cost and transportation time, assumes that there is a stochastic transportation time between both producer and buyer, and that shortages are allowed. The transportation time is assumed to be Weibull distributed. The objective functions of the integrated model include the setup cost, inventory carrying cost, and delivery cost. We analyze the scenario where the delivery cost is explicitly considered in the model rather than considered as part of the fixed ordering cost or insignificant. A numerical example is also presented to demonstrate the proposed model using actual shipping rate data. In particular, the results show that when the producer's and buyer's carrying costs are low, and/or the mean time of transportation and delivery costs are high, then this can benefit both parties with regard to sharing total profit.     

考虑交货期的生产运输联合优化问题研究

结合企业实际场景研究了考虑交货期的多个工厂、多条生产线、单一产品的生产与运输联合优化问题.已知客户订单需求量和交货时间窗,考虑了各条生产线在不同时段的生产能力约束,在满足交货时间窗约束的前提下,以生产、存储、运输费用之和极小化为目标建立了生产与运输联合优化问题的混合整数规划模型,通过分析模型结构证明了在不考虑固定生产成本的情况下,模型等价于最小费用最大流问题,得出了直接用Gurobi软件求解模型的可行性.最后利用具体算例进行模拟计算并与企业目前采用的顺序优化方法进行对比,发现采取联合优化策略可以明显降低总费用,并随着单位运输成本的增加,联合优化策略较顺序优化策略的优势在不断扩大.研究成果为企业制定生产与运输计划提供了理论依据.     

Coordination of production and interstage batch delivery with outsourced distribution

In this paper, we consider coordinated production and interstage batch delivery scheduling problems, where a third-party logistics provider (3PP) delivers semi-finished products in batches from one production location to another production location belonging to the same manufacturer. A batch cannot be delivered until all jobs of the batch are completed at the upstream stage. The 3PP is required to deliver each product within a time T from its release at the upstream stage. We consider two transportation modes: regular transportation, for which delivery departure times are fixed at the beginning, and express transportation, for which delivery departure times are flexible. We analyze the problems faced by the 3PP when either the manufacturer dominates or the 3PP dominates. In this context, we investigate the complexity of several problems, providing polynomiality and NP-completeness results.     

智能制造环境下的备件生产与运输协同调度问题研究

智能制造和即时配送环境下的备件生产与运输协同调度问题是目前国内研究的一大热点,这是因为备件供应链响应速度已成为当前备件制造企业赢得客户的关键因素。为了提高客户满意度,尽可能缩短从客户下达定制化生产订单到订单配送完成的时间,本文建立了以所有客户总等待时间最短为目标的混合整数规划模型和集合覆盖模型,推导了最优解性质,并设计改进的分支定价算法求得最优解。通过将小规模算例结果与CPLEX进行对比,验证了模型和算法的有效性。多组算例测试结果表明,所提出的模型和算法可以有效提升智能制造环境下的备件供应链运作效率。     

Impacts of inventory shortage policies on transportation requirements in two-stage distribution systems

This paper investigates the impacts inventory shortage policies have on transportation costs in base-stock distribution systems under uncertain demand. The model proposed demonstrates how backlogging arrangements can serve to decrease the variability of transportation capacity requirements, and hence the magnitude of transportation costs, when compared with policies that expedite demand shortages. The model shows how inventory policy decisions directly impact expected transportation costs and provides a new method for setting stock levels that jointly minimizes inventory and transportation costs. The model and solution method provide insights into the relationship between inventory decisions and transportation costs and can serve to support delivery policy negotiations between a supplier and customer that must choose between expediting and backlogging demand shortages.     

Logistics Planning in the Downstream Oil Industry

Strategic logistics chain planning is of great importance within the downstream oil industry. Logistics networks originate at refineries and terminate at the final delivery point — the customer. Types of bulk transportation used and the main product classes are described. The business decisions which need to be addressed are stated. A corresponding model is formulated partly in mathematical and partly in qualitative terms. The cost of road vehicle delivery to customers is modelled. The business risks associated with changes to the logistics infrastructure are indicated.     

Heuristic guided simulator for the operational planning of the transport of sugar cane

This paper presents a computational tool for the operational planning of the transportation of sugar cane to mills. A simulation model was developed to serve as a basis for a heuristic which automatically allocates the equipment available at a mill to the different collection points so that the sugar cane available can be loaded for delivery with the minimal amount of equipment. The program is user-friendly, and compatible with Windows. The approach used emphasises the flexibility of the model and the interactiveness possible during the planning process. Successful trial tests with real data are reported.     

An efficient mixed integer programming model for pairing containers in inland transportation based on the assignment of orders

The inland transportation takes a significant portion of the total cost that arises from intermodal transportation. In addition, there are many parties (shipping lines, haulage companies, customers) who share this operation as well as many restrictions that increase the complexity of this problem and make it NP-hard. Therefore, it is important to create an efficient strategy to manage this process in a way to ensure all parties are satisfied. This paper investigates the pairing of containers/orders in drayage transportation from the perspective of delivering paired containers on 40-ft truck and/or individual containers on 20-ft truck, between a single port and a list of customer locations. An assignment mixed integer linear programming model is formulated, which solves the problem of how to combine orders in delivery to save the total transportation cost when orders with both single and multiple destinations exist. In opposition to the traditional models relying on the vehicle routing problem with simultaneous pickups and deliveries and time windows formulation, this model falls into the assignment problem category which is more efficient to solve on large size instances. Another merit for the proposed model is that it can be implemented on different variants of the container drayage problem: import only, import–inland and import–inland–export. Results show that in all cases the pairing of containers yields less cost compared to the individual delivery and decreases empty tours. The proposed model can be solved to optimality efficiently (within half hour) for over 300 orders.     

Synchronizing production and air transportation scheduling using mathematical programming models

Traditional scheduling problems assume that there are always infinitely many resources for delivering finished jobs to their destinations, and no time is needed for their transportation, so that finished products can be transported to customers without delay. So, for coordination of these two different activities in the implementation of a supply chain solution, we studied the problem of synchronizing production and air transportation scheduling using mathematical programming models. The overall problem is decomposed into two sub-problems, which consists of air transportation allocation problem and a single machine scheduling problem which they are considered together. We have taken into consideration different constraints and assumptions in our modeling such as special flights, delivery tardiness and no delivery tardiness. For these purposes, a variety of models have been proposed to minimize supply chain total cost which encompass transportation, makespan, delivery earliness tardiness and departure time earliness tardiness costs.