Integrated production scheduling and preventive maintenance planning for a single machine under a cumulative damage failure process

This paper finds the optimal integrated production schedule and preventive maintenance plan for a single machine exposed under a cumulative damage process, and investigates how the optimal preventive maintenance plan interacts with the optimal production schedule. The goal is to minimize the total tardiness. The optimal policy possesses the following properties: Under arbitrary maintenance plan when jobs have common processing time, and different due dates, the optimal production schedule is to order the jobs by earliest due date first rule; and when jobs have common due date and different processing times, the optimal production schedule is shortest processing time first. The optimal maintenance plan is of control limit type under any arbitrary production schedule when machine is exposed under a cumulative damage failure process. Numerical studies on the optimal maintenance control limit of the maintenance plan indicate that as the number of jobs to be scheduled increases, the effect of jobs due dates on the optimal maintenance control limit diminishes. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Machine maintenance with workload considerations

Machine maintenance is modeled in the setting of a single‐server queue. Machine deterioration corresponds to slower service rates and failure. This leads to higher congestion and an increase in customer holding costs. The decision‐maker decides when to perform maintenance, which may be done pre‐emptively; before catastrophic failures. Similar to classic maintenance control models, the information available to the decision‐maker includes the state of the server. Unlike classic models, the information also includes the number of customers in queue. Considered are both a repair model and a replacement model. In the repair model, with random replacement times, fixed costs are assumed to be constant in the server state. In the replacement model, both constant and variable fixed costs are considered. It is shown in general that the optimal maintenance policies have switching curve structure that is monotone in the server state. However, the switching curve policies for the repair model are not always monotone in the number of customers in the queue. Numerical examples and two heuristics are also presented. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

模糊自适应PMHT机动目标跟踪算法

对目标机动的检测和准确跟踪,是目标跟踪研究中非常重要但难度较大的问题.将统计距离、统计距离增量作为系统方差的调整参量,采用模糊专家规则系统,提出了一种适用于机动目标的模糊自适应概率多假设跟踪(FA-PMHT)算法.该算法将数据关联寻优与运动模型寻优联合处理,从而实现了数据关联寻优、目标模型寻优一体化.仿真结果表明,所提算法与交互式多模型概率多假设跟踪(IMM-PMHT)算法相比在跟踪精度上有明显提高,并且满足实时性要求,证明该算法是有效的.     

模糊神经网络在发电机励磁控制中的应用

采用含有惯性项学习算法的BP神经网络代替模糊PID控制器,对同步发电机励磁控制系统进行仿真。仿真结果表明,在系统遭受扰动或突加减载时,所设计的模糊神经网络励磁控制器具有良好的控制效果。     

基于损伤树及损伤征兆集的战场损伤定位研究

建立了基于损伤树的知识表示、知识推理模型及损伤树评估框架,利用损伤树各节点的损伤征兆集,进行装备战场损伤定位,较好地利用了装备专家的领域知识,提高了战场损伤评估的准确性和效率。     

基于模糊评判的某行星转向机故障预测研究

为了实现对自行火炮传动系统的预测维修,以行星转向机为例,运用动态模糊综合评判的办法,提取引起行星转向机典型故障的关键影响因素,探讨了动态模糊判断矩阵和动态权重的确定方法,在此基础上确定了其动态预测模型,并用实例验证了模型的正确性。     

中国警察参与联合国维和行动风险分析

风险管理是一门新兴学科,已普遍应用于各个领域。维和工作处处充满风险,有必要进行深刻探讨,进而对中国警察参与联合国维和行动面临的风险进行科学合理的分析并提出应对措施。     

C~4ISR系统任务实时性的评价方法

提出一种定量评价C4ISR(Command Control Communication Computer Intelligence Surveillance and Reconnaissance)系统任务实时性方法--时序着色模糊时间Petri网(TCFTPN)方法.用时序逻辑公式来限制着色Petri网的变迁引发行为,用模糊时间来表示各工作过程的时延特性和降级工作问题.通过估计在规定的时间内标识从任务开始状态到达任务完成状态的概率来确定C4ISR系统的任务实时性.     

自行火炮作战效能分析与模糊综合评价

自行火炮以其机动性强,火力反应快,防护性能好,成为炮兵的重要组成部分和机动作战的骨干力量,但由于自身的复杂性和作战应用的多样性,其作战效能受多方面的因素影响,运用层次分析法确定影响作战效能的指标权重系数,结合模糊综合评价方法将子效能合并成整体体系效能,由此实现自行火炮作战效能的定量化评估。     

基于贝叶斯网络的装备损伤定位系统研究

分析了贝叶斯网络在装备损伤定位方面的优势,及其损伤定位的方法与流程,建立了用于装备损伤定位的贝叶斯网络模型,并开发了损伤定位系统。以某型火炮为例,演示了其损伤定位的一般过程,验证了贝叶斯网络在装备损伤定位中应用的可行性与有效性。