可靠性概率

Based on the equivalent transformation from fuzzy possibility distribution to random probability density distribution, the fuzzy random failure probability calculation can be formulated easily, and a First Order and Second Moment method for fuzzy - random analysis is established.

提出了模糊随机可靠性分析的近似解析和数字模拟综合方法，基于模糊变量的等价随机化变换，可以方便地得到模糊随机失效概率的计算公式，并建立了模糊随机可靠性分析的一次二阶矩法。

This paper presents the mechanism of erosion scour around groynes of levee projects and a probability method of the reliability analysis for groyne erosion under random factors.

分析了防护丁坝冲刷的机理，用概率分析方法研究了在随机因素影响下防护丁坝抗冲刷的可靠性问题。应用Rosen-blatt变换确定防护丁坝抗冲刷破坏的功能函数在随机因素影响下的可靠性指标。

The advantages and limitations of every kind of methods for calculating the failure probability is reviewed. The frist order reliability method, the second order reliability method and many kinds of boundary method have achieved remarkable success and formed nature fields of reliability. However, the precision of these methods decrease as the increase of complexity of problem. The numrical methods are versatile, except numerical intergration is only adaptable to special problems which have small number variables and regular intergral domain. Particularly, the advanced variance reduction techniques own the following character: high precision and a small amount computation. But some questions remain to study in the future because only an initial work about these techniqes is developed.

全面评述了计算失效概率各种方法的优点和局限性，其中经典的解析法包括一次可靠性方法、二次可靠性方法、一阶边界法、Vanmarcke上边界、PENT上边界和Ditlevsen二阶窄边界法，这些方法对于多设计点、变量较多且相关、密度函数不是正态以及极限状态方程较复杂的情况，其计算精度较差；而已有的数值方法却是具有较好的通用性，其中除数值积分法只对变量较少、积分域较规则的特殊问题适用外，各种数值模拟方法均具有较广的适应性，特别是各种改进的方差减小技术，精度高、计算量小，但由于其处在研究的初级阶段，还有许多问题有待于解决。

We mainly research on more complicated reparable system: Convert Fault Tree model based on factor analysis to SPN of system; Describe the running of reparable system by use of state transition.

这里我们主要针对较为复杂的可修复系统部分进行重点研究，将故障树转化为大系统的随机Petri网模型，利用状态转移来描述可修系统部分的运行情况，由其状态转移概率建立系统的状态方程，从而得到系统的稳态可靠性，再结合不可修系统部分对整个大系统进行全面综合的分析，提出了基于随机Petri网的复杂大系统的可靠性分析方法。

To analyze the reliability of oil pipeline ,the traditional methods of the evaluation for reliability ,based on the theory of reliability and supposal of failure rate ,regard the pipeline as a system of series connection or parallel connection .

对长输管道可靠性进行评估的传统方法是，将管道结构视为一个串联或并联系统，运用可靠性的理论概念和各种失效概率假设，以故障率的统计资料为计算依据来进行可靠度的计算分析，可靠度也采用故障率等参数来表达。

Logical analysis and formula of total probability are used to establish the main electrical wiring reliability model,and computation algorithms for complex wiring are derived.

对发电厂电气主接线可靠性计算进行原理分析，利用逻辑分析和全概率公式建立电气主接线可靠性模型，进而推导出面对工程中各种复杂主接线方式的计算方法。

Analyzing the dependent failure and stepwise computing the reliability of a parallel system, the reliability model of cumulative fatigue damage of a load sharing parallel system is developed according to the total probability formula and Miner theory.

为了有效处理载荷共享并联系统的可靠性问题，首先分析了并联系统的相关失效，并分步计算并联系统可靠度，应用全概率公式和Miner理论对并联系统进行了疲劳累积损伤可靠性建模。

A new optimal power flow model with reliability constraint is proposed to obtain an economic and secure operation schedule of the power system, where the reliability index constraint is constructed based on z transform theory to take the uncertainties of electric power system into account, and the objective aims at minimizing the total cost of the system to satisfy the expected loss of load probability.

提出一种考虑可靠性指标的最优潮流模型。该模型能考虑系统中的随机因素，通过z变换法构造电力系统的可靠性指标约束，将该约束添加到经典最优潮流模型中共同求解，从而使电为系统的调度或控制能在满足一定的失负荷概率指标的前提下实现最优运行。

Finally, the index of non-probabilistic reliability is introduced in mathematic model of optimization design, and optimizations of axle shaft structure of machine tool and hollow conveying shaft based on non-probabilistic reliability model are presented. The engineering examples show that the presented methods are convenient and effective.

最后，将机械的非概率可靠性指标引入到优化设计的数学模型中，分别对空心传动轴和机床主轴结构进行了可靠性优化设计，通过工程实例说明了该方法是简便和有效的。

The financial risk of the electric utility is obtained according to the probabilistic characteristic of power supply reliability indices. Then the MV distribution network structure multiobjective planning model under PBR reliability government is constructed.

根据规划网架供电可靠性指标的概率分布特性得到供电公司面临的奖惩风险指标，进而建立PBR可靠性管理模式下的中压配电网网架多目标规划模型。

Fancy gold-plated dangling earrings with facetted White Opal crystals.

花式镀金悬垂耳环与facetted白欧泊水晶。

This essay chooses the study aim from biology teachers in middle school in Shi Jiazhuang which tells us that most of the middle school biology teachers in Shi Jiazhuang have the"burnout", lower successfulness, individualize.

本文选取石家庄市初中生物教师作为研究对象，运用问卷调查的方法对石家庄市初中生物教师职业倦怠的现状进行调查，调查结果发现，石家庄市初中生物教师这一群体普遍存在职业倦怠，情感枯竭程度偏高，成就感偏低，去个性化程度最为严重。