浅析专业的数据中心外包服务

本文以外包服务的角度分析了专业的数据中心服务。提出了专业的数据中心建设标准问题,给出了外包服务的三个等级,为不断提高外包服务能力给出了方向性的建议。通过可用度方法的引入,介绍了如何实现和评估数据中心的高可靠、高效率的运行。通过强调管理的作用,提示出高标准的服务主要依赖于人而非设备（系统）。     

基于虚拟现实的装甲装备维修性定量指标验证方法研究

对维修性定量指标验证的研究现状进行分析,提出构建基于虚拟现实的产品维修性定量指标验证系统;首先,根据系统需求构建出系统的总体框架;其次,对系统搭建过程和仿真过程中的关键技术进行阐述;再者,对国军标中维修性定量参数估计模型进行改进,构建适用于复杂装备的虚拟仿真MTTR估计模型;最后,在验证系统中对某型车辆传动装置进行MTTR虚拟仿真试验,并运用MTTR估计模型进行MTTR验证;对比得到,通过虚拟仿真试验得到的验证结果与实车试验数据得到的结果基本一致,具有较高的可信性;该方法为在产品研制设计阶段并行维修性定量指标的验证工作提供了非常重要的参考价值。     

Collaborative multi-step mono-level multi-strategy classification

In this paper, we address the problem of retrieving a movie from a set of multimedia(MM) servers by the clients on a network. We consider a strategy in which multiple MM servers are deployed by the service provider (SP) to retrieve a requested MM movie to the clients, for minimizing the access time (the waiting time of the client before initiating the playback) and maximizes the system reliability. We design a movie retrieval strategy that explicitly considers issues such as reliability and/or availability factors of the multimedia servers and the communication channels in the problem formulation. We develop a mathematical model for this retrieval strategy and derive an optimal size of each movie portion that is expected to be rendered by each server. We then derive a closed-form expression for the access time of the MM document and the system reliability which gives a trade-off relationship between access time and reliability (availability) of the service by our strategy. We extend our study to investigate on the effect of sequencing of the servers, the order in which movie portions are to be retrieved, to minimize the access time and to maximize the system reliability. With system reliability factors, we identify an optimal sequence, which maximizes system reliability out of all possible retrieval sequences. We then propose two methods to retrieve any missing movie portions upon a server failure during the retrieval process. In order to measure the quality of service provided by the service provider to its customers, we introduce a QoS parameter that can tune the playback rate to avoid any data underflow or overflow situations. Then, from probabilistic perspective, we obtain an estimate of the failure time of a single server and its resulting missing movie portion caused by this server failure. We conduct rigorous simulation experiments to testify all the theoretical findings reported. Illustrative examples are provided for the ease of understanding.     

LED户外全彩屏的MTBF和可靠性

介绍了LED户外全彩屏的平均无故障时间(MTBF)及可靠性，着重讨论了提高全彩屏可靠性的几个问题。提出建立合理的可靠性模型，加强可靠性试验，建立故障分折与纠正措施系统(FRACAS)和确定平均修复时间(MTTR)。     

机载无源相控阵雷达天线的维修性设计

文中提出了机载无源相控阵天线维修性存在的难度,介绍了天线维修性设计要求和几种典型的维修性设计方式,指出了各种维修方式对环境条件的要求及其优、缺点探讨了天线维修性设计的改进途径。对提高系统的"三性"设计也作了初步探讨。     

模块化UPS可靠性计算与分析

文章通过对模块化UPS系统的基本可靠性/任务可靠性/可用性指标计算,分析出有冗余的模块化UPS系统的可用度会大大提高。对于模块化UPS系统,系统的瓶颈将是静态开关以及模块的独立性(故障模块的可靠退出和正常模块的顺利接入UPS系统)。     

一种X频段天线有源子阵的维修性设计与分析

有源子阵结构集成度高、电讯功能复杂,是影响有源相控阵天线维修性的重要因素。文中展示了一种高集成模块化X频段天线有源子阵。通过在子阵上设计安装导向装置,提高了有源子阵重复拆装的可靠性。利用分层盲插设计,避免了子阵装配维修过程中的连接器误接错插问题。基于模块化维修设计思路,在子阵内部合理定义现场可更换单元（Line Replaceable Unit, LRU）,保障了子阵集成模块的互换性,提高了现场基层维修的效率。以平均修复时间（Mean Time To Repair, MTTR）为指标对有源子阵的维修性进行分析,结果表明该子阵满足X频段相控阵天线快速维修性的设计要求。     

系统MTBF和MTTR的一种求解方法

针对目前MTBF和MTTR获取的不规范性,应用贝叶斯估计求解系统的MTBF和MTTR,依据MTBF和MTTR的先验分布,利用贝叶斯公式求出它们的后验分布,然后利用贝叶斯估计得到MTBF和MTTR的估计值。最后运用一个实例验证了该方法的正确性。     

鱼雷平均修复时间验证试验方法

鱼雷平均修复时间（MTTR）验证试验是试验鉴定中的重点内容,MTTR是考核鱼雷测试性、维修性及评估鱼雷战备完好性的关键指标。本文明确了MTTR验证试验的基本思路,规划了利用自然故障和模拟故障进行试验的试验实施方法和过程,并制定了明确的试验结果评定标准,该方法可直接指导鱼雷设计定型试验项目的实施。     

减少MTTR提高模块化UPS系统可用性

本文介绍了模块化UPS在物流、安装和可维护性的优势,然后细分模块MTTR的组成对模块化UPS可用性的影响,最后计算出在模块不同MTTR时的系统的可用度。