Minimizing maximum lateness on one machine: computational experience and some applications

We consider the problem of scheduling jobs on a single machine subject to given release dates and precedence constraints, in order to minimize maximum lateness. The algorithms of B aker and S u (Naval Res. Logist. Quart. 21 (1974) 171–176) and of M c M ahon and F lorian (Operations Res. 23 (1975) 475–482) for the problem without precedence constraints are extended to the general case. An extensive computational comparison establishes the superiority of the latter algorithm. We describe applications to the theory of job-shop scheduling and to a practical scheduling situation.     

Action variety of planners: Cognitive load and requisite variety

The complexity of planning tasks have increased over the past decade. There is relatively poor understanding what the implications are of increased task complexity in planning and scheduling operations. Previous work in the behavioral sciences have investigated the concept of cognitive load, addressing both task complexity and task workload or stress, and have concluded that decision makers tend to resort to routine action and reduce the variety in their actions with increasing complexity and workload. Alternatively, control theory suggests that a higher variety of actions is needed to deal with more complex problems. In this paper, we investigate the effects of task complexity in a chemical plant on the variety of actions deployed by the planners. The single work center resource structure and the availability of actual planning data from an MRP-application database allows us to both use field data and study a situation which is simple enough to measure the main effect. Our results suggest that increased task complexity without time pressure does indeed lead to increased action variety deployed by the planners.     

Approaches to multiplicity issues in complex research in microarray analysis

The multiplicity problem is evident in the simplest form of statistical analysis of gene expression data – the identification of differentially expressed genes. In more complex analysis, the problem is compounded by the multiplicity of hypotheses per gene. Thus, in some cases, it may be necessary to consider testing millions of hypotheses. We present three general approaches for addressing multiplicity in large research problems. (a) Use the scalability of false discovery rate (FDR) controlling procedures; (b) apply FDR-controlling procedures to a selected subset of hypotheses; (c) apply hierarchical FDR-controlling procedures. We also offer a general framework for ensuring reproducible results in complex research, where a researcher faces more than just one large research problem. We demonstrate these approaches by analyzing the results of a complex experiment involving the study of gene expression levels in different brain regions across multiple mouse strains.     

Planning horizons for master production scheduling

Production and operations planning in organizations quite often is a multi-level sequential process, involving aggregate planning, master production scheduling, and detailed operations planning and scheduling. To obtain good planning results, it is desirable to have a proper planning horizon for each level of planning. There have been a considerable number of studies dealing with planning horizons for aggregate planning or production smoothing problems. There are also many planning horizon studies for single-item lot sizing problems. No study has addressed the issues associated with the planning horizons for master production schedules (which is a multi-item lot sizing problem in nature), particularly with respect to the relationship to the aggregate plan.This study addresses the issue of planning horizons for companies employing a make-to-stock competitive strategy facing a seasonal demand for their products. We formulate the aggregate planning problem and the master scheduling problem as two separate mathematical programs to approximate the two-stage process that typically takes place in practice. Rolling planning horizons are used to approximate the periodic updates of the plans commonly done in practice. The models also incorporate resource requirements planning concepts to estimate loads on the critical work centers.The planning process is simulated as a single pass procedure where the results of aggregate planning are passed to the master production scheduling model once per month and the results of the master scheduling model (i.e., the portion of the master schedule actually implemented) are passed back to the aggregate planning model for the next planning session.The experimental results show that when the planner faces extreme cost structures such as high smoothing costs/high setup costs or low smoothing costs/low setup costs, the planning horizon effects are reduced to a minimum. Master schedule planning horizons need not be as long as aggregate planning horizons. Alternatively, non-extreme cost structures such as high smoothing costs/low setup costs and low smoothing costs/high setup costs should be handled with equal planning horizons for both aggregate planning and master scheduling.It is also found that the firm's cost structure has an impact on the appropriate planning horizon for both aggregate planning and master scheduling. Some cost conditions allow for smaller master schedule horizons. The best horizon choice seems to be equal planning horizons for both aggregate planning and master scheduling, even though the cost savings is slight in some cases.Finally, the proper length of the planning horizon for master scheduling is affected by the planning horizon of the aggregate plans.     

Personnel scheduling in public systems: a survey

In many public systems efficiencies may be realized by improved personnel scheduling. This paper surveys the literature on personnel scheduling in the public domain. Two general problems are considered: the daily scheduling problem where hourly employee work day patterns are determined and the weekly scheduling problem where day off and day on work week patterns are constructed. The daily problem is discussed in terms of scheduling with and without simultaneous work assignment; and the weekly problem is dichotomized into those schedules based on cyclical personnel requirements and those that are not.     

景电工程梯级泵站运行调度及管理

阐述景电工程梯级泵站运行调度的重要性,结合景电工程多年实际运行情况,针对调度工作中存在的一些问题,提出调度管理的任务、制度以及调度的职责和权限、基本依据、任务和要求等。     

带车辆路线安排的多配送中心选址问题的求解——基于SPSS和遗传算法

研究了带车辆路线安排的多配送中心选址问题。首先根据宏观的定量指标对需求点运用SPSS进行区域划分,将一个多配送中心选址问题转化为多个单配送中心选址问题,然后,在一辆配送车一次只能为一个需求点供货的情况下,建立并求解了单配送中心选址问题的整数线性规划模型;在一辆配送车一次可以为多个需求点供货的情况下,用遗传算法求出了最佳车辆配送路线和最佳选址位置。     

Scheduling independent jobs on nonuniform, unequal processors

The problem of scheduling n independent jobs on a single processor to minimize the total tardiness of the assignment has attracted much attention. Solution algorithms, both exact and approximate, have been reported, but no polynomial time exact algorithm has yet been found, nor has the problem been proven NP-complete.In this paper we consider the more general case of scheduling n independent jobs on m unequal processors to minimize total tardiness. Since this problem is more complex than the corresponding single-processor problem, no polynomial-time algorithm is in sight. For problems of this nature, approximate algorithms may be more valuable than exact algorithms in terms of applications. A heuristic algorithm is developed to solve the multiple-processor problem. Computational experiments show that the heuristic algorithm is efficient, fast, and easy to implement.     

两库联合调度工程经济效益研究

在我国水资源严重短缺和水资源压力不断加重的背景下,水资源的联合调度成为了解决我国水资源问题的重要途径,并凸显出相较于单方面水量配置或是水质配置的优越性。因此,本文针对合理地调度水库流域水量的问题来做探讨,希望此联合调度工程能对我国水利工程的进一步加强有所帮助。     

基于虚拟流水线的船舶分段建造调度问题研究

针对传统船舶分段制造中出现的生产等待、时间冗余等问题,应用虚拟流水线生产模式的方法进行生产系统改造。在满足约束的前提下,建立以作业班组在生产系统中的流通时间最短为目标的班组调度模型。针对分段车间调度问题应用一种基于混合蚁群遗传算法(Mixed AntColony and Genetic Algorithm,MACGA)实现了作业班组的优化调度。最后,以某造船厂分段加工车间为例,验证了虚拟流水线模式及其调度方法可以有效的提高船舶分段的生产效率。     

用爱烘干你潮湿的心——浅谈单亲家庭高职生的心理问题及调适

在学生群体中,单亲家庭高职生的心理教育最难收到成效,究其原因,由于这类学生的心理产生了一定程度的扭曲,且由于这种扭曲具有复杂性、封闭性和持久性等特点,本文就谈谈单亲家庭高职生的心理问题及对策。     

具有模糊加工时间的Flexible Job-Shop Scheduling问题的研究

采用梯形模糊数来表征柔性生产系统中的时间参数,并在此基础上对具有模糊加工时间的柔性作业车间最小化制造跨度调度问题进行了描述。然后给出了基于粒子群优化的柔性作业车间调度模型。最后通过实例验证了模型的有效性。     

基于JIT采购的3PL运输调度问题研究

研究Just in Time(JIT)背景下制造商主导的第三方物流(Third Party Logistics,3PL)运输调度问题。制造商根据其生产计划的要求进行采购。使用C-W路线优化算法,在线路规划中考虑了车辆载重量、容积以及车辆到达时间的影响,实现以最小的成本达到JIT采购的目的,并用一个实例验证了修正的C-W算法对解决采购物流中运输调度问题的适用性。     

多配送中心单向车辆调度问题的模型与禁忌搜索算法的研究

在对无时间窗和软时间窗多配送中心单向车辆调度问题进行直观描述的基础上,分别建立了相应问题的数学模型。提出了直接解决多配送中心单向车辆调度问题的禁忌搜索算法,设计了求解多配送中心单向车辆调度问题的算法流程,并对已经存在的实例进行了实验计算。     

自动化堆场混合堆存模式下双轨道吊协同调度策略与优化

针对自动化堆场混合堆存模式下双轨道吊协同调度问题,进行了双轨道吊安全存取的无缝对接研究,通过分析它们在空间上的接力方式,以及时间上的接力顺序,提出在时空约束下交接点滚动变化的轨道吊交接策略;同时,构建双轨道吊协同调度模型,并将装卸效率和设备成本作为目标函数,然后运用遗传算法求解。通过比较分析四种调度策略,设置不同规模试验,证明接点影响船舶和堆场的装卸效率,但对设备成本影响不大,而双轨道吊协同调度会提高船舶装卸效率,为港口运营管理提供了一些参考。     

基于“实验项目”的排课选课系统设计与实现

本文通过分析我校实验排课现状和存在的问题,重点介绍了高校实验项目排课选课系统的功能模块设计。作为教务管理系统中的子系统,提高了教务管理部门的工作效率,为实验项目学分制改革提供了软件支持,推进了教务管理的信息化建设。     

关于电网调度管理一体化探讨

针对关于电网调度管理一体化探讨问题,介绍了我国当前电网运行调度管理的现状问题,主要包括电网调度运行管理存在的问题和电网调度运行需要实施一体化的管理模式,并探讨了电网调度运行管理及调度一体化改进与优化建议,提出了电网在调度运行管理方面的建议和电网在调度一体化方面的建议,希望电网在管理一体化模式中为人民供好电力资源。     

生产管理课程教学改革初探

在回顾目前生产管理课程教学现状的基础上,分析了生产管理课程的实践性和应用性,强调了生产管理课程教学改革的必要性,并提出了教学改革的途径,即:注重课堂教学的多样性和灵活性、加强生产管理课程的课内实验环节、完善生产管理课程的课外实践环节,例如借鉴"卓越工程师"教育培养计划等。     

MRP with high uncertain yield losses

Certain manufacturing systems, notably those in high technology precision casting and integrated circuit production suffer from process yield losses which are both significant in quantity terms and are also highly unpredictable. This poses special problems for the provisioning of materials to support a manufacturing program and for the detailed scheduling necessary to update the priorities of work in process batches as losses occur. This paper establishes a framework of analysis to handle this problem in MRP logic. It describes the mechanisms available and discusses their relevance to the market environments in which the company is operating.The key conclusion of this paper is that different solutions are required for different market circumstances. The four key strategies developed are:

1. A: For continuous schedules, make-for-stock: Use mean yield rate and fixed buffer stocks.

2. B: For continuous schedules, make-to-order: Use mean yield rate, fixed buffers and a yield to finish monitoring system.

3. C1: For single batch production make-to-order: As for B but using a desired service level yield rate.

4. C2: For multiple batch production, make-to-order: As B but using a variable yield rate by batch.

The implementation of each of these is described in relation to the business objectives of cost effectiveness and customer satisfaction.     

Operations Research in passenger railway transportation

In this paper we give an overview of state-of-the-art Operations Research models and techniques used in passenger railway transportation. For each planning phase (strategic, tactical and operational), we describe the planning problems arising there and discuss some models and algorithms to solve them. We do not only consider classical, well-known topics such as timetabling, rolling stock scheduling and crew scheduling, but we also discuss some recently developed topics such as shunting and reliability of timetables.
Finally, we focus on several practical aspects for each of these problems at the largest Dutch railway operator, NS Reizigers.