Reliability‐based Optimal Maintenance Scheduling by Considering Maintenance Effect to Reduce Cost

A new reliability‐based optimal maintenance scheduling method is presented that considers the effect of maintenance in reducing costs. An ordering list of element maintenance effects with various maintenance‐interval types is constructed. By means of this ordering list, reliability‐based optimal maintenance scheduling for simple reliability structures and composite reliability systems is then carried out. The properties of the proposed method, such as the evaluation of maintenance cost reduction, the simplicity of the proposed method by sacrificing system availability within the allowance method, the operation decision based on the optimal maintenance schedule, etc., are discussed. With simulations, the effectiveness of the proposed method is verified. Copyright © 2005 John Wiley & Sons, Ltd.     

一类柔性机器人装配系统的优化调度

研究了印刷电路板柔性机器人装配系统的中的优化调度问题,该系统中的机器人都具有一定的柔性,因而某些装配操作可由不同的机器人来完成,且所需装配时间也可以不同。本文针对这类机器人装配系统,采用一种新算法,以解决此类系统的优化调度问题,并通过算例验证了该逄法的有效性。     

工件带到达时间并具有成组约束的车间排序算法

针对模具制造过程的特点,在工件不同时到达的情况下,研究了前阶段带有成组约束的两阶段柔性同序加工车间的调度问题,建立了目标函数为最小化最大完成时间的调度数学模型．基于Potts的RJ’算法提出解决此类问题的启发式算法,并将该算法应用到轮胎模具企业的生产实例中,通过仿真说明数学模型和求解方法的可靠性和有效性．     

基于差分进化算法的供水系统节能调度研究

针对当前供水系统节能降耗的需求,根据供水系统运行特点,利用合理划分调度期的方式,建立了以节能为目标的优化调度模型;采用差分进化算法对模型进行求解,应用实数编码将决策变量表示为进化种群中的个体;运用罚函数法对约束条件进行转换,并使用加法和乘法的形式进行组合,构建了适应度函数;采用标准差分策略进行变异操作;以天津市中心城区供水系统为例,验证了模型与差分进化算法的有效性,并与遗传算法进行了对比,显示出前者在求解该模型上具有一定的优势。     

变频驱动并联水泵变压变流量运行优化调度

分析了变频驱动并联水联水泵变压变流量运行优化调度问题的常用建模方法,并比较了各种方法的优劣。常用的方法是以水泵轴功率作为目标函数,以供水指标和高效区为约束条件。另一种方法是以满足扬程指标时的实际流量与所需流量之差的二次方作为目标函数,以水泵的高效区作为约束条件。提出了一种新的建模方法,模型物理意义与实际工况严格相符,具有较高的精度,满足了工程中对水泵切换频率尽量小的要求。仿真结果表明该方法是有效的。     

Mixed Self-adapting GA Optimal Scheduling Algorithm for a Multiple Resource Job-shop

With an aim at the job-shop scheduling problem of multiple resource constraints, this paper presents mixed self-adapting Genetic Algorithm （ GA ） , and establishes a job-shop optimal scheduling model of multiple resource constraints based on the effect of priority scheduling rules in the heuristic algorithm upon the scheduling target. New coding regulations or rules are designed. The sinusoidal function is adopted as the self-adapting factor, thus making cross probability and variable probability automatically change with group adaptability in such a way as to overcome the shortcoming in the heuristic algorithm and common GA, so that the operation efficiency is improved. The results from real example simulation and comparison with other algorithms indicate that the mixed self-adapting GA algorithm can well solve the job-shop optimal scheduling problem under the constraints of various kinds of production resources such as machine-tools and cutting tools.     

加强软件质量控制,提高军用软件的可靠性水平

针对军用软件在质量和可靠性方面存在的问题，提出了提高军用软件质量和可靠性的措施和方法。     

关于软件可靠性测试的若干问题

软件可靠性测试是软件测试的一种形式,它强调软件测试与软件可靠性之间的定量关系,旨在定量改进和评估软件可靠性。从数学角度严格量化软件测试与软件可靠性之间的关系是一件困难的事情。本文举例说明软件可靠性测试中的几个问题,包括软件缺陷的估计、软件测试过程的数学建模、以及软件可靠度的最优估计等。由此可知,软件可靠性测试涉及到不同领域的知识和多种数学工具。     

软件测试数据的统计分析

软件可靠性评估是软件可靠性研究的重要问题,本文研究了软件测试数据的样本点序法,获得了软件可靠度的置信下限,证明了该置信限的最优性。最后给出一个实例说明该方法的可行性。     

燃气动力大通径补贴装置的设计与试验

现有套管补贴技术存在通径小的缺陷,燃气动力大通径补贴技术能够解决这一问题。通过设计包含燃气动力装置、气流转换装置、锚定装置、扩径装置的系统装置来实现补贴目的,补贴后通径可达到原套管内通径的90%以上,能够满足现有注采设备通过的要求,地面实验验证了设计合理性。     

Computational Analysis and Optimization for Smart Patching Repairs

A classical cracked metallic structure, repaired with a smart bonded composite patch with embedded optical fibers (to detect the strain field variations of the loaded structure), has been studied here-in. Finite element analysis was used, where-in the composite patch was modeled as a layered structure with three-dimensional elements constituting six different laminae. Each lamina is assumed to have different mechanical properties, according to the studied case, in order to simulate different stacking sequence. A resin rich eye pocket has also been modeled in order to simulate the exact form of resin area produced during the manufacturing process. The patch is bonded over a cracked aluminum sheet through a small adhesive layer placed in between. External loads were applied only on the metal structure, as in a real repair case. The primary loading axis of the metal was assumed to be parallel to the direction of the optical fibers. Due to the different nature of the materials that form the composite patch, complex mechanical interactions between the fibers and the surrounding material occur, resulting in a complicated strain field along the optical fiber sensor. This affects the structural integrity of both the patch and the repair. Different optical fiber layer positions were considered, to study their effect on the resulting strain field and the structural integrity of the patch. Analysis concluded that the best available embedding position of an optical fiber in a laminated patch coincides to the one predicted as neutral surface, according to Rose's analytical equations.     

水工混凝土结构裂纹修补加固材料的研究进展

针对水工混凝土结构裂缝的严重危害,分析了水工混凝土产生裂缝的原因,介绍了近年来国内外新研制、开发应用的修补加固材料及其技术,并从修补加固材料角度详细阐述了裂缝的预控措施,对水工混凝土构筑物病害处理具有指导意义。     

Economic analysis of software release problems with warranty cost and reliability requirement

We discuss optimal software release problems which consider both a present value and a warranty period (in the operational phase) during which the developer has to pay the cost for fixing any faults detected. It is very important with respect to software development management that we solve an optimal software testing time by integrating the total expected testing cost and the reliability requirement. We apply a nonhomogeneous Poisson process model to the formulation of a software cost model and analyze three typical cases of the cost model. Moreover, we derive several optimal release polices. Finally, numerical examples are shown to illustrate the results of the optimal policies.     

基于软件总线的星载系统软件结构的研究与设计

针对目前国内外星载系统软件可重构性较差的问题，提出了一种基于软件总线的星载系统软件结构。首先，介绍了软件总线和软构件的结构。其次，阐述了星载实时多任务操作系统中混合任务调度算法的设计。最后，对这个混合任务调度算法的正确性给出了证明。     

某测试软件输入模块的可靠性测试方法研究

采用黑盒测试方法对某数据采集系统的测试软件进行了测试.通过对软件需求和性能的分析,建立了软件的运行剖面和测试案例,进行了可靠性测试,得到了该软件输入模块的可靠性测试结果.     

淮河群库优化调度系统的设计与实现

首次提出了采用基于并行计算技术的高性能计算方法进行加优化调度的方法,并采用客户／服务器模式在曙光１０００并行机上设计实现了淮河群库优化调度系统。结果表明：其调度的准确性大大优于常规调度,并缩短了整个决策时间,由此产生的经济效益和社会效益是难以估量的。     

Optimal Scheduling of Track Maintenance on a Railway Network

To ensure the safety and continued operation of the railway network system, many maintenance and renewal activities are performed on the track every month. Unplanned maintenance activities are expensive and would cause low service quality. Therefore, the track condition should be monitored, and when it has degraded beyond some acceptable limit, it should be scheduled for maintenance before failure. An optimal timetable of the maintenance activities is needed to be scheduled, planning the monthly workload, to reduce the effect on the transportation service and to reduce the potential costs. Considering the uncertainties of the deterioration process, the safety of transportation service, the lifetime loss of the replaced track, the maintenance cost and the travel cost, this article advances an optimisation model for the maintenance scheduling of a regional railway network. An enhanced genetic algorithm approach is proposed to search for a solution producing maintenance schedule such that the overall cost is minimised in a finite planning horizon. A case study is given to demonstrate the application of the method. The case study results were derived by using an enhanced genetic algorithm method, which is specifically developed to deal with the characteristics of the railway maintenance problem. Copyright © 2012 John Wiley & Sons, Ltd.     

一类多资源调度问题的优化算法

若调度系统中的作业或任务需要一个或多个资源共同完成， 则这一类调度问题被称为多资源（或多处理机）调度问题。本文针对Jobshop中的这一调度问题，提出了基于遗传的优化调度算法，并用实例证实了该算法的有效性。     

Software Aging and Rejuvenation in a J2EE Application Server

Recently, software aging and software rejuvenation have been widely researched by both academic and industrial communities. Software aging is characterized by progressive performance degradation or a sudden hang/crash in a long‐running software system due to resource exhaustion of the operating system. Software rejuvenation is a proactive and preventive maintenance technique to counteract software aging. In this work, the memory leak in Java virtual machine (JVM) is firstly analyzed, and then the software aging phenomenon in a J2EE application server is investigated. To mitigate software aging effects and prevent the system from failing, the hierarchical software rejuvenation method by partial or total restarting of the system is presented. Finally, the experimental results proved that the proposed method is superior to the periodical rejuvenation method in the aspect of improving system performance. Copyright © 2014 John Wiley & Sons, Ltd.     

经济批量与运送排产问题中的协调机制研究

针对现有研究采用集中决策的局限,研究了分散决策情形下经济批量与运送排产问题的最优决策。分析表明在无协调机制作用时,分散决策无法实现供应链系统的最优绩效,进一步提出一种利润共享和成本分担协议（PCS）,并证明在PCS协议作用下,采用分散决策可以实现供应链协调,同时供应链利润可以在供需双方任意分配,具有很好的柔性。