带工期指派的产品服务系统订单随机调度问题研究

针对由一个制造工厂和多个区域服务中心组成的服务型制造企业,研究了考虑生产时间和服务时间均具有随机性且工期可指派的产品服务系统（PSS）订单调度问题。首先以最小化订单提前、误工和工期指派费用的期望总额为目标构建问题的优化模型,然后分析目标函数近似值的最优性条件,据此提出加权最短平均生产时间排序规则,并结合该规则与插入邻域局部搜索设计了启发式算法对问题进行求解,最后通过数值仿真验证算法的可行性和有效性。研究表明,提前费用偏差对PSS订单调度与工期指派决策的影响很小,因此企业管理者无需准确估计库存费用也能制定出比较有效的PSS订单调度策略;而工期指派费用偏差对决策结果的影响非常大,因此企业管理者在决策时必须谨慎估计该项费用。     

并行工程产品开发过程定量化建模与计划制订

由于现有的一些并行工程定量化模型中修改设计微循环的细节特征描述得还不够充分 ,本文提出了一种新的基于产品 -工艺设计活动对网络的定量化模型来描述并行工程产品开发过程 ,并且给出了产品 -工艺设计活动对平均持续时间与产品或工艺设计活动资源占用率的计算方法 .在此基础上 ,将并行工程产品开发过程的计划制订问题建模成一个有资源约束的项目调度问题 .与其它此类问题不同的是 ,在本文中 ,分配给产品开发项目的各类资源的数量不是事先给定的 ,而是与最优产品开发计划一起获得的 ,所以这是一个资源分配与计划制订的集成优化问题 .本文提出了一种新的基于分枝定界的算法来解决此问题并引入一个启发式规则来提高算法的搜索效率     

基于遗传算法的资源约束型项目调度优化

资源约束型项目调度的优化是一个NP-hard问题,其求解难度随着资源约束项的增多呈指数方式增长,传统的基于Excel表的手工优化方法不能及时计算出有效的资源配置方式,从而影响项目管理人员的资源调度.针对多资源约束型项目调度的优化问题提出基于遗传算法的资源约束型项目调度的优化方法,该算法采用基于活动优先权的十进制编码方式,结合活动的存储邻接矩阵,有效地解决活动调度违例现象;运用优先抢占模式的资源分配方式安排活动资源,避免资源分配中的冲突问题;并为该算法设计了启发式遗传算法的C语言程序,通过计算机的多次迭代运算得出满足资源约束的最优工期.实践结果表明,遗传算法可以快速有效地解决企业项目调度的优化问题,适合在企业项目进度管理中推广运用.     

CIMS－PPC系统作业排序问题研究

本文探讨了在现代制造系统概念下，作业排序的目标及物流控制采用的策略，提出了一种ＣＩＭＳ－ＰＰＣ系统作业排序方法的逻辑模型和数学模型．     

蓝黄九市经济-生态-社会的协调发展

通过以蓝黄九市2005—2014的面板数据为基础,运用协同学理论构建蓝黄九市经济-生态-社会协调发展模型,分析蓝黄九市三系统的发展现状及演化过程可以看出,经济、生态、社会三系统之间具有较强的互补作用。2014年青岛市耦合协调度水平最高,德州市最低。除青岛市达到优质协调外,其余城市的协调类型为:日照市、潍坊市、滨州市、淄博市、德州市属经济发展相对滞后型;烟台市属生态发展相对滞后型;威海市、东营市属社会发展相对滞后型。经济系统关键影响因子是GDP等,生态系统关键影响因子是污水集中处理率等,社会系统关键影响因子是公用设施投资等。     

基于深度强化学习的救护车动态重定位调度研究

救护车是挽救患者生命的重要医疗资源,合理调配有限的救护车资源可以降低呼叫响应时间,提高医疗服务水平.本文面向救护车动态重定位调度问题,提出了一种基于强化学习的调度策略结构.为解决传统强化学习所面临的高维状态空间的挑战,本文基于深度Q值网络(DQN)方法,提出了一种考虑多种调度交互因子的算法RedCon-DQN,以在给定环境状态下得到最优的重定位调度策略.在此基础上,本文还提出了急救网络弹性概念,以评估各站点对全局救护优化目标的影响力.最后,基于南京市2016年~2017年的实际救护车呼叫及响应数据,构造了环境交互模拟器.在模拟器中通过大规模数据实验,验证了模型得到的调度策略相比已有方法的优越性,并分析了不同时段下调度策略的有效性及其特点.     

Some heuristic algorithms for total tardiness minimization in a flowshop with blocking

The flowshop scheduling problem with blocking in-process is addressed in this paper. In this environment, there are no buffers between successive machines; therefore intermediate queues of jobs waiting in the system for their next operations are not allowed. Heuristic approaches are proposed to minimize the total tardiness criterion. A constructive heuristic that explores specific characteristics of the problem is presented. Moreover, a GRASP-based heuristic is proposed and coupled with a path relinking strategy to search for better outcomes. Computational tests are presented and the comparisons made with an adaptation of the NEH algorithm and with a branch-and-bound algorithm indicate that the new approaches are promising.     

Dynamic scheduling of steel casting and milling using multi-agents

This paper presents a case study on the use of multi-agents for integrated dynamic scheduling of steel milling and casting. Steel production is an extremely complex problem requiring the consideration of several different constraints and objectives of a range of processes in a dynamic environment. Most research in steel production scheduling considers static scheduling of processes in isolation. In contrast to earlier approaches, the multi-agent architecture proposed consists of a set of heterogeneous agents which integrate and optimize a range of scheduling objectives related to different processes of steel production, and can adapt to changes in the environment while still achieving overall system goals. Each agent embodies its own scheduling model and realizes its local predictive-reactive schedule taking into account local objectives, real-time information and information received from other agents. Agents cooperate in order to find a globally good schedule, which is able to effectively react to real-time disruptions, and to optimize the original production goals whilst minimising disruption carried by unexpected events occurring in real-time. The inter-agent cooperation is based on the Contract Net Protocol with commitment.     

An adjustable robust optimization model for the resource-constrained project scheduling problem with uncertain activity durations

This paper addresses the resource-constrained project scheduling problem with uncertain activity durations. An adaptive robust optimization model is proposed to derive the resource allocation decisions that minimize the worst-case makespan, under general polyhedral uncertainty sets. The properties of the model are analyzed, assuming that the activity durations are subject to interval uncertainty where the level of robustness is controlled by a protection factor related to the risk aversion of the decision maker. A general decomposition approach is proposed to solve the robust counterpart of the resource-constrained project scheduling problem, further tailored to address the uncertainty set with the protection factor. An extensive computational study is presented on benchmark instances adapted from the PSPLIB.     

Clinical Capital and the Risk of Maternal Labor and Delivery Complications: Hospital Scheduling,Timing, and Cohort Turnover Effects

The establishment of interventions to maximize maternal health requires the identification of modifiable risk factors. Toward the identification of modifiable hospital‐based factors, we analyze over 2 million births from 2005 to 2010 in Texas, employing a series of quasi‐experimental tests involving hourly, daily, and monthly circumstances where medical service quality (or clinical capital) is known to vary exogenously. Motivated by a clinician's choice model, we investigate whether maternal delivery complications (1) vary by work shift, (2) increase by the hours worked within shifts, (3) increase on weekends and holidays when hospitals are typically understaffed, and (4) are higher in July when a new cohort of residents enter teaching hospitals. We find consistent evidence of a sizable statistical relationship between deliveries during nonstandard schedules and negative patient outcomes. Delivery complications are higher during night shifts (OR = 1.21, 95% CI: 1.18–1.25), and on weekends (OR = 1.09, 95% CI: 1.04–1.14) and holidays (OR = 1.29, 95% CI: 1.04–1.60), when hospitals are understaffed and less experienced doctors are more likely to work. Within shifts, we show deterioration of occupational performance per additional hour worked (OR = 1.02, 95% CI: 1.01–1.02). We observe substantial additional risk at teaching hospitals in July (OR = 1.28, 95% CI: 1.14–1.43), reflecting a cohort‐turnover effect. All results are robust to the exclusion of noninduced births and intuitively falsified with analyses of chromosomal disorders. Results from our multiple‐test strategy indicate that hospitals can meaningfully attenuate harm to maternal health through strategic scheduling of staff.