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Chemotherapy appointment scheduling is a challenging problem due to the uncertainty in premedication and infusion durations. In this paper, we formulate a two‐stage stochastic mixed integer programming model for the chemotherapy appointment scheduling problem under limited availability of nurses and infusion chairs. The objective is to minimize the expected weighted sum of nurse overtime, chair idle time, and patient waiting time. The computational burden to solve real‐life instances of this problem to optimality is significantly high, even in the deterministic case. To overcome this burden, we incorporate valid bounds and symmetry breaking constraints. Progressive hedging algorithm is implemented in order to solve the improved formulation heuristically. We enhance the algorithm through a penalty update method, cycle detection and variable fixing mechanisms, and a linear approximation of the objective function. Using numerical experiments based on real data from a major oncology hospital, we compare our solution approach with several scheduling heuristics from the relevant literature, generate managerial insights related to the impact of the number of nurses and chairs on appointment schedules, and estimate the value of stochastic solution to assess the significance of considering uncertainty. 相似文献
213.
对于毛细管节流的动静压轴承,基于流量平衡方程和偏导形式的流量平衡方程,本文建立了油腔压力和油腔压力偏导的迭代准则和迭代公式。实践证明,该迭代方法具有物理意义明晰、迭代次数少和迭代适应性强的特点,可以显著提高毛细管节流的动静压轴承静动特性分析计算有限元程序的计算速度。 相似文献
214.
介绍超宽带线性调频信号基带的数字产生方法及其实现技术。首先对线性调频信号的两种主要数字产生方法进行了简要阐述和比较,然后根据波形存储直读法提出了一种超宽带线性调频信号产生方案,分析了基带数字产生的主要关键技术,并进行了系统实现和测试。测试结果表明本文所提出的方法是可行的。 相似文献
215.
为解决指挥系统控制中的调度困难,研究了一类特殊的传感器资源调度问。主要分析了跟踪目标的探测次数、时间间隔和传感器资源等约束条件。用跟踪目标的重要程度之和作为目标函数,建立了一个0-1规划的数学模型,再利用变换将其转化为0-1线性整数规划模型。利用割平面法求解得出最优调度策略,其能在工作量饱和的情况下合理调度传感器资源。为提高求解速度,提出了对应的模拟退火算法。通过对一些不同规模实例的求解,在资源利用率和算法的求解速度等指标上,与割平面法及遗传算法进行对比分析,验证了模型的有效性和模拟退火算法求解的高效性。 相似文献
216.
We study two‐agent scheduling on a single sequential and compatible batching machine in which jobs in each batch are processed sequentially and compatibility means that jobs of distinct agents can be processed in a common batch. A fixed setup time is required before each batch is started. Each agent seeks to optimize some scheduling criterion that depends on the completion times of its own jobs only. We consider several scheduling problems arising from different combinations of some regular scheduling criteria, including the maximum cost (embracing lateness and makespan as its special cases), the total completion time, and the (weighted) number of tardy jobs. Our goal is to find an optimal schedule that minimizes the objective value of one agent, subject to an upper bound on the objective value of the other agent. For each problem under consideration, we provide either a polynomial‐time or a pseudo‐polynomial‐time algorithm to solve it. We also devise a fully polynomial‐time approximation scheme when both agents’ scheduling criteria are the weighted number of tardy jobs. 相似文献
217.
本文讨论了在大规模并行计算机上实现数据并行程序设计语言的关键问题──分布数组的地址计算问题。文中详细给出了维分布数组的下标地址计算公式,分布数组的内情向量结构以及分布数组映射函数算法,并对有关编译实现技术进行了探讨。 相似文献
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The well‐known generalized assignment problem (GAP) involves the identification of a minimum‐cost assignment of tasks to agents when each agent is constrained by a resource in limited supply. The multi‐resource generalized assignment problem (MRGAP) is the generalization of the GAP in which there are a number of different potentially constraining resources associated with each agent. This paper explores heuristic procedures for the MRGAP. We first define a three‐phase heuristic which seeks to construct a feasible solution to MRGAP and then systematically attempts to improve the solution. We then propose a modification of the heuristic for the MRGAP defined previously by Gavish and Pirkul. The third procedure is a hybrid heuristic that combines the first two heuristics, thus capturing their relative strengths. We discuss extensive computational experience with the heuristics. The hybrid procedure is seen to be extremely effective in solving MRGAPs, generating feasible solutions to more than 99% of the test problems and consistently producing near‐optimal solutions. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 468–483, 2001 相似文献
220.
We study a workforce planning and scheduling problem in which weekly tours of agents must be designed. Our motivation for this study comes from a call center application where agents serve customers in response to incoming phone calls. Similar to many other applications in the services industry, the demand for service in call centers varies significantly within a day and among days of the week. In our model, a weekly tour of an agent consists of five daily shifts and two days off, where daily shifts within a tour may be different from each other. The starting times of any two consecutive shifts, however, may not differ by more than a specified bound. Furthermore, a tour must also satisfy constraints regarding the days off, for example, it may be required that one of the days off is on a weekend day. The objective is to determine a collection of weekly tours that satisfy the demand for agents' services, while minimizing the total labor cost of the workforce. We describe an integer programming model where a weekly tour is obtained by combining seven daily shift scheduling models and days‐off constraints in a network flow framework. The model is flexible and can accommodate different daily models with varying levels of detail. It readily handles different days‐off rules and constraints regarding start time differentials in consecutive days. Computational results are also presented. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 607–624, 2001. 相似文献