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Coordinated scheduling in production, delivery, and storage systems.

机译:生产,交付和存储系统中的协调调度。

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摘要

In a typical supply chain, raw materials are transported to factories where items are produced, and finished products are first shipped to warehouses for intermediate storage, and then delivered to retailers or customers. To achieve optimal operational performance in a supply chain, it is critical to schedule the production, delivery and storage operations in a coordinated manner. In this thesis, we present three topics motivated by coordinated scheduling in production, delivery, and storage systems.; First, we develop and analyze a singlenrachine scheduling model that incorporates the scheduling of jobs and the pickup and delivery arrangements of the materials and finished jobs. In this model, there is a capacitated pickup and delivery vehicle that travels between the machine and the storage area, and the objective is to minimize the makespan of the schedule. The problem is strongly NP-hard in general but is solvable in polynomial time when the job processing sequence is predetermined. An efficient heuristic is developed for the general problem. The effectiveness of the heuristic is studied both analytically and computationally.; Second, we consider a scheduling model with two machines at different locations. Each job is composed of two tasks where each task must be processed by a specific machine. The finished tasks are shipped to a distribution center in batches before they are bundled together and delivered to customers. The objective is to minimize the sum of the delivery cost and customers' waiting costs. This model attempts to coordinate the production and delivery schedules on the decentralized machines while taking into consideration the shipping cost as well as the waiting time of the customers. We develop polynomial-time heuristic algorithms for this problem and analyze their worst-case perfbrmance. Computational experiments are conducted to test the effectiveness of the heuristics and to evaluate the benefits obtained by coordinating the production and delivery of the two decentralized machines.; Third, we consider the scheduling of truck arrivals at an air cargo terminal. By coordinating arrivals of cargo delivery trucks with outbound flight departure schedules, some of the shipments can be transferred directly to the departing flights, while others will be stored at the terminal's storage facility and incur extra handling and storage costs. The objective is to obtain a feasible schedule so as to minimize the total cost of operations. We formulate the problem as a time-indexed integer program and show that, with limited number of unloading docks at the terminal, the problem is non-trivial (NP-hard in the strong sense). Our solution methods include an exact solution procedure to determine an optimal unloading sequence for the shipments carried by each truck, together with a Lagrangian relaxation based heuristic for assigning trucks to truck docks and determining truck arrival times. We conducted computational experiments to test the performance of our solution methods. Our simulation results indicate that the proposed scheduling approach has the potential to generate significant cost savings over a first-come, first-served approach currently used at the air cargo terminal that we observed.
机译:在典型的供应链中,原材料被运送到生产物品的工厂,而成品首先被运送到仓库进行中间存储,然后再交付给零售商或客户。为了在供应链中实现最佳运营绩效,以协调的方式安排生产,交付和存储操作至关重要。在本文中,我们提出了三个主题,这些主题受生产,交付和存储系统中的协调调度的启发。首先,我们开发和分析一个单机器调度模型,该模型包含作业调度以及物料和已完成作业的拾取和交付安排。在此模型中,有一个容量大的皮卡车和送货车在机器和存储区域之间行驶,目的是最大程度地减少计划的工期。通常,该问题对NP的影响很大,但是当预定了作业处理顺序时,可以在多项式时间内解决。针对一般问题开发了一种有效的启发式方法。启发式的有效性在分析和计算上都得到了研究。其次,我们考虑在不同位置有两台机器的调度模型。每个作业由两个任务组成,其中每个任务必须由特定计算机处理。完成的任务被捆绑在一起并交付给客户之前,被分批运送到配送中心。目的是使交付成本和客户等待成本的总和最小化。该模型试图协调分散机器上的生产和交货计划,同时考虑运输成本以及客户的等待时间。我们针对此问题开发了多项式时间启发式算法,并分析了它们的最坏情况性能。进行计算实验以测试启发式方法的有效性,并评估通过协调两个分散式机器的生产和交付所获得的收益。第三,我们考虑安排卡车到达航空货运站的时间。通过将货运卡车的到达与出站航班起飞时间表进行协调,一些货物可以直接转移到出发航班,而其他货物将存储在码头的存储设施中,并产生额外的装卸和存储成本。目的是获得可行的时间表,以最大程度地减少运营总成本。我们将该问题表示为时间索引整数程序,并表明,在码头的卸货码头数量有限的情况下,该问题并非微不足道的(从严格意义上讲,NP是难的)。我们的解决方案方法包括精确的解决方案过程,以确定每辆卡车所载货物的最佳卸货顺序,以及基于拉格朗日松弛法的启发式方法,用于将卡车分配到卡车码头并确定卡车到达时间。我们进行了计算实验,以测试我们的求解方法的性能。我们的仿真结果表明,与我们观察到的空运货站目前使用的先到先得方法相比,拟议的调度方法具有节省大量成本的潜力。

著录项

  • 作者

    Jinwen, Ou.;

  • 作者单位

    Hong Kong Polytechnic University (Hong Kong).;

  • 授予单位 Hong Kong Polytechnic University (Hong Kong).;
  • 学科 Engineering Industrial.; Operations Research.; Computer Science.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 138 p.
  • 总页数 138
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 一般工业技术;运筹学;自动化技术、计算机技术;
  • 关键词

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