基于节点能量的主动路由维护算法

在无线自组织网（MANETs）中对于服务质量（QoS）的支持是一项很有挑战的任务，而路由算法是保证QoS的一种重要手段，路由维护又是路由算法的一个重要组成部分。文中在分析了已有路由维护算法的基础上，提出了一种基于AODV的主动路由维护算法，它能够满足延时的严格要求，并且仅需要相对较少的网络资源。     

论高校大学生的高级科普内容与形式

《全民科学素质行动计划纲要》没有将高校大学生纳入重点人群之列,这个现象说明有关方面对"高学段人群"在提高全民科学素质水平上的拉动作用重视不够。对高校大学生的科学素质研究在理论和实践上还缺乏坚实的科学观基础,科学教育的体系和内容还非常杂乱。因此,应当针对我国重专业轻综合的传统教育缺陷,加强现阶段大学生的综合性科学教育,即"高等级科普";通过借鉴国外的成熟科学素质理论和先进经验,总结我国近年来的文化素质教育实践,建立合理的大学生科学素质评价体系和综合性科学素质培养体系。     

Reliability-centered predictive maintenance scheduling for a continuously monitored system subject to degradation

This paper tries to integrate sequential imperfect maintenance policy into condition-based predictive maintenance (CBPM). A reliability-centered predictive maintenance policy is proposed for a continuously monitored system subject to degradation due to the imperfect maintenance. It is assumed that the system hazard rate is a known function of the system condition and then can be derived directly through CBPM. A hybrid hazard rate recursion rule based on the concept of age reduction factor and hazard rate increase factor is built up to predict the evolution of the system reliability in different maintenance cycles. Whenever the system reliability reaches the threshold R, an imperfect preventive maintenance (PM) is performed on the system. The optimal reliability threshold R is determined by minimizing the cumulative maintenance cost per unit time in the residual life of the system which is based on simulation. Finally, a discussion is presented to show how the optimal results depend on the different cost parameters.     

Analysis of on-line maintenance strategies for -out-of- standby safety systems

The objective of this paper is to compare the performance of three on-line test and maintenance strategies (corrective maintenance, preventive maintenance and predictive maintenance) for standby k-out-of-n safety systems. Each channel of the k-out-of-n system is modelled by an age-dependent unavailability model to reflect the effect of maintenance on the aging process. The system unavailability, the probability of spurious operation and the overall cost under the above maintenance strategies are analyzed and compared to obtain the optimal maintenance strategy. Sensitivity analyses are performed to reveal the effect of different model parameters on the system performance. A standby safety system in Canadian Deuterium–Uranium (CANDU) Nuclear Power Plants (NPPs), the Shutdown System Number One (SDS1), is used to illustrate the proposed analysis and the procedure. It is concluded that maintenance should neither be performed too frequently nor too rarely. When the system deteriorates very slowly, the corrective maintenance is more preferable than the preventive and predictive maintenance. When the failure rate of the system is high, the preventive maintenance results in the best system performance.     

光缆线路外包维护的决策与管理

光缆传输网是我国信息化建设的基础网络,其运行和维护水平直接影响服务质量.但相对于其它主通信设备而言,光缆线路是非核心设备,其维护技术含量较低、劳动密集程度高,企业易控制,适宜外包维护.分析了光缆线路维护的问题、外包决策动因,讨论了外包维护的内容与方式,并对外包维护的过程管理和改进措施进行了探讨.     

国外高等职业教育的质量观

随着高等教育的大众化,高等教育,尤其是高等职业教育的质量问题受到世界许多国家的关注,纷纷采取措施确保高等职业教育的质量与水准。英、澳、美、德等国家对于高等职业教育质量的观点和做法是值得我们借鉴的。     

县乡公路水泥混凝土路面损伤的原因及维修措施

发展县乡公路已成为目前公路建设的主要任务,县乡公路一般为水泥混凝土道路,可往往县乡公路的水泥混凝土道路在使用期内就出现断板、裂缝、沉陷、坑槽、麻面等病害,给养护工作带来很大困难,并且严重影响行车舒适性和安全性。通过县乡公路混凝土面板断裂原因的分析,对县乡公路混凝土的设计、施工、养护进行了一些有益的探讨。     

航空阀控式免维护铅酸蓄电池的充电方法研究

简要分析了阀控式免维护铅酸蓄电池的特点,探讨了现行充电方法的优点和缺点,提出了阀控式免维护铅酸蓄电池在没有恒压充电机的情况下,应采用多阶段恒流充电的方法来延长蓄电池的寿命。     

有关日志数据预处理的研究

在日志数据的预处理中,确定合适的挖掘粒度是一项重要任务.本文介绍了一种日志数据预处理模型,在一般预处理模型基础上添加了页面视图识别环节,从而使日志数据有了更精确的挖掘粒度,挖掘结果有更强的语义.     

专科院校“计算机组装与维护“公选课教学初探

通过对一定范围内用人单位对员工的计算机应用能力需要的调查,与在校生计算机应用能力的考察结果进行对比,初步反映了目前专科生提高计算机维护能力的重要性紧迫性.以社会需求为基本依据,以就业为导向,以学生为主体,参考新的就业形势,分析探讨了专科院校开设“计算机组装与维护“校级公选课的可行性和必要性,展示了本课程的梗概.