Availability estimation of a multi-state wind farm in fuzzy environment

Wind is one of the fastest growing renewable energy resources in the electric power system. Availability of wind energy is volatile in nature due to the stochastic behavior of wind speed and non-linear variation of the wind power curve of wind turbine generator. Because of this impression and uncertainty, the availability estimation of wind power has become a challenging issue. In this paper, Markov Fuzzy Reward technique has been proposed for finding out the reliability of wind farm by assessing the availability of wind power. According to this technique, availability of the wind power has been estimated considering wind farm and demand both as a multi-state system. In addition to the availability, different reliability indices such as the number of absolute failures, mean time to deficiency, and probability of failures of a wind farm have been assessed in a time horizon, which can provide useful information for the power system planner at wind farm installing stage. A comparison of this study reveals the efficacy of the proposed Markov Fuzzy Reward approach over the conventional Markov Reward approach.     

有源相控阵可靠性分析及设计

基于有源相控阵原理和特点,对有源相控阵可靠性特征展开了分析。在同等复杂度下,采用可靠性表决模型和全串联模型对可靠性特征进行了对比分析,给出了有源相控阵表决模型设计的工程经验参数,并利用氮化镓器件对有源相控阵高可靠性设计进行了展望。     

基于多目标优化的装备群备件保障决策研究

针对装备群备件保障决策问题,从装备群-装备两个层次进行分析建模和优化。首先,根据可靠性分配方法将装备群系统可靠性分配给各装备子系统,在此基础上,考虑总费用和保障概率的要求,利用pareto多目标优化方法对各子系统装备所需携(运)行的备件进行合理优化,建立一个多目标优化决策模型。最后结合应用实例展开应用研究,可为装备群系统决策从定性到定量提供一种新的思路。     

基于结构方程模型的认知性VDT作业过程解析*

为实现通过过程控制和管理提高认知性视觉显示终端（VDT）作业人员可靠性和绩效的目标,应用结构方程模型（SEM）研究作业过程表征方法。构建认知性VDT作业的信息加工过程模型,抽取13个基本认知动素（CT）,提出CT概念结构模型假设,设计外显指标测试题项,运用问卷调查样本数据构建结构方程和测量方程;对测量数据与结构方程模型的拟合度进行分析,并训练BP神经网络模式识别模型对作业过程进行还原检验。结果表明:认知性VDT作业过程模型有效,元认知控制其他12个CT的结构关系成立,认知性VDT作业过程可由包括元认知在内的13个基本CT解析。     

Early warning signals noticed,but management doesn't act adequately or not at all: a brief analysis and direction of possible improvement

History has taught us that quite disastrous events with much human loss, injuries and asset damage could have been prevented or at least mitigated, if top management had recognized early warning signals in some form as urgent and had decided to take timely preventative measures. It turns out to be a rather common phenomenon in various sectors of life and some process industry examples are presented. The problem is further analyzed from a leadership point of view, from organizational structure and culture aspect, and what modern technology developments can help to improve the situation. Research in the latter directions is encouraged.     

基于灰色关联服役构件的可靠度评估研究

为获取服役构件的待定可靠指标以便为决策服务,用共维条件下排序方法通过影响因素的映射进而评估待定指标。采用通过分析服役受弯构件的性能来确定其可靠度影响因素,进而根据层次递阶原理建立可靠度评价指标体系。然后利用可变模糊集理论中模糊量化理论(FQT)的概念确定各影响因素的权重,再根据权重结果利用灰色关联分析法(GRA)计算构件的可靠指标的相对顺序,最后得到待定构件的可靠指标范围。实例研究结果表明,将FQT理论和GRA有机结合,能够有效刻画影响因素的互交性、判断准则的模糊性及所获取相关信息不完备的灰色性等特点,并且评估结果与实际情况吻合。     

基于多级物元分析法的弹药维修安全评价

针对弹药维修安全的特殊性,运用多级物元分析法,在综合考虑基础条件建设、业务管理水平、环境以及弹药本身等因素的基础上,提出了一种新的弹药维修安全评价方法,对弹药维修的安全性进行了评价.在明确了主要包括制定指标体系、一级评价和二级评价的弹药维修安全评价的方法与步骤的基础上,以某工厂进行某典型弹药维修为例,进行验证.结果表明...     

Use and attack on expert testimony in toxic substances litigation∗

Expert testimony is available in cases where persons, qualified through skill, knowledge, experience, education or training can be helpful to the trier of the facts in coming to a determination. Historically, courts have given experts wide latitude with respect to their qualifications as well as to the bases of their opinions. Recently, some courts, because of concern about a developing body of “professional experts”, are taking steps to more carefully survey the opinion of experts before permitting their testimony to get to the jury. Both the historical development and some of the recent decisions are discussed.     

含表面应力集中超高温陶瓷材料热冲击可靠性的研究

目的研究含表面应力集中的超高温陶瓷材料在热冲击环境下的可靠性。方法针对超高温陶瓷材料,研究了其威布尔分布规律和含不同切口半径的材料可靠性,并建立了其在热冲击载荷作用下的可靠性评价方法。结果对于切口不完全敏感的材料,切口件的可靠性并不是随着切口半径的减小而单调增大,对于研究的三种切口半径试样(r=0.1、0.25、0.5 mm),r=0.1 mm的试样存活率最小,r=0.25 mm的试样存活率最大。淬火初期阶段,表面含切口的材料存活率在0.04 s内急剧降低至0,0.04～0.1 s时存活率维持在0,0.1 s后存活率迅速上升,约0.28s后存活率增大为1。结论建立的评价方法可以作为超高温陶瓷材料在热冲击环境下应用可靠性的有效评估手段,对其进一步被广泛应用具有重要意义。     

热带海洋环境下舰艇携行弹药的环境效应分析

分析了我国东海、南海和印度洋亚丁湾海域的气候环境特征,在此基础上,结合弹药在舰艇上的存放/使用位置分析,得出了环境因素对不同位置舰艇携行弹药的影响程度。鉴于环境因素对弹药的环境影响效应是综合性的,以弹药防护包装、弹体、装药、引信等分系统为对象,分别开展了环境效应分析,综述了其在热带海洋环境下的环境效应。建议加强舰艇携行弹药局部环境监测、损伤效应与机理研究,并建立数据库,为我军舰艇携行弹药环境适应性设计与验证、环境控制措施和维护保养措施制定提供数据基础,支撑我国海军不断走向深蓝。