共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
关于MIL—HDBK—781中的保证试验 总被引:3,自引:0,他引:3
美国军用标准 MIL— H DBK— 781中的保证试验以其所需的试验时间短而引起可靠性工程界的广泛关注。本文指出这种试验方案存在不合理之处 ,并提出了避免不合理因素的修正方案 ,还从贝叶斯统计角度论证了这种修正方案是有道理的 ,值得实际工作中采用。 相似文献
3.
4.
使用正交试验设计方法设计出试验方案,对总体数据用方差分析等方法对选择方案进行期望评估,从而避免了常规试验中由于随机误差导致的判断失误,达到了试验效率非常高的效果. 相似文献
5.
混合截尾试验是定时和定数截尾的一种有用的推广。本文研究了Weibull分布和混合截尾试验的一次抽样方案,并对可靠决策损失函数给出了贝叶斯风险的显式表达式。比较陈和林的模型(1999),我们得混合截尾试验的抽样方案于定时抽样方案。 相似文献
6.
《数学的实践与认识》2017,(17)
为了避免经典方法中Fisher信息矩阵的繁琐计算,并考虑两个或更多应力因子对加速寿命试验的影响,提出了基于区间删失数据的I最优加速寿命试验方案并进行了相应的灵敏度分析.将产品的正常使用条件考虑为一个应力水平组合的区域,I最优准则使得在这个区域上产品寿命的平均预测方差最小.假定失效时间分布服从Cox比例风险模型(Proportional Hazard Model),继而对区间删失数据使用广义线性模型(Generalized Linear Model)方法以得到I最优准则下的加速寿命试验方案,最后从模型参数、检测区间数、样本量、试验时间等角度进行了试验方案的灵敏度分析,验证了试验方案的稳健性,并讨论了如何利用这些因素来降低试验敏感性. 相似文献
7.
关于定时截止寿命试验中的最大似然估计 总被引:3,自引:0,他引:3
<正> 在工业品寿命试验的实际工作中,强烈要求缩短试验时间,不必等到所有试件都坏了才结束试验工作.针对这一点,有一种有用的试验方案,就是所谓“定时截止寿命试验”方案,即所有试件试验到某个预先给定的时刻为止,不再继续下去了.在[1]中介绍了这种方案,给出了寿命分布中所含未知参数的最大似然估计法,并应用到指数分布上去.我们 相似文献
8.
9.
10.
11.
12.
利用多元转移概率流图及转移概率母函数,对带有中止检查规则的调整型抽样方案进行了讨论,分别在(1)当检查始于正常检查时,(2)当检查始于加严检查时和(3)当检查始于放宽检查时,得到了三个复合OC函数. 相似文献
13.
vague集的多指标决策问题的优劣点法 总被引:3,自引:2,他引:1
就vague集的多指标决策问题,引入了方案集的最优点和最劣点的概念,由此给出了vague集多指标决策问题的优劣点法.首先计算各方案的各单指标对理想vague值[1,1]的投影和距离,从而建立评价矩阵,然后根据评价矩阵的各单一指标对应数值的大小得到方案的最优点和最劣点,通过计算各方案到最优点和最劣点的距离以及接近度对方案进行排序,得出最优方案.该方法简单实用,所需信息少,实例验证了该方法的有效性. 相似文献
14.
Calculus has been witnessing fundamental changes in its curriculum, with an increased emphasis on visualization. This mode for representing mathematical concepts is gaining more strength due to the advances in computer technology and the development of dynamical mathematical software. This paper focuses on the understanding of the function and its derivative as viewed by students of a reformed Calculus 1 course offered in two experimental sections at the Lebanese American University in Beirut, Lebanon. Results have shown that the general approach adopted in the course proved to be unpopular for a great majority of the students, but rewarding for others. Interviews conducted with some students and a study of their performance on very specific exam questions reveal that for most students, the algebraic representation of a function still dominated their thinking; however, these students showed an almost complete understanding of the derivative, particularly the idea of the instantaneous rate of change and/or the slope of a curve at a given point. Furthermore, very few of these students referred to the mechanical methods for finding derivatives. 相似文献
15.
Hari K. Rajagopalan F. Elizabeth Vergara Cem Saydam Jing Xiao 《European Journal of Operational Research》2007
This article employs a statistical experimental design to guide and evaluate the development of four meta-heuristics applied to a probabilistic location model. The meta-heuristics evaluated include evolutionary algorithm, tabu search, simulated annealing, and a hybridized hill-climbing algorithm. Comparative results are analyzed using ANOVA. Our findings show that all four implementations produce high quality solutions. In particular, it was found that on average tabu search and simulated annealing find their best solutions in the least amount of time, with relatively small variability. This is especially important for large-size problems when dynamic redeployment is required. 相似文献
16.
生产计划与调度决策支持系统的研究 总被引:1,自引:0,他引:1
章对生产计划与调度决策支持系统进行了研究,设计了基于知识库和模型库的具有定量因子和定性因子的生产计划与调度基本模型,该模型可对半结构化决策问题,提供决策支持。 相似文献
17.
This paper proposes a multiple dependent (or deferred) state sampling plan by variables for the inspection of normally distributed quality characteristics. The decision upon the acceptance of the lot is based on the states of the preceding lots (dependent state plan) or on the states of the forthcoming lots (deferred state plan). The lot acceptance probability is derived and the two-point approach to determining the plan parameters is described. The advantages of this new variables plan over conventional sampling plans are discussed. Tables are constructed for the selection of parameters of this plan under the specific values of the producer’s and consumer’s risks, indexed by acceptable quality level and limiting quality level, when the standard deviation is known or unknown. 相似文献
18.
本文选取了2008年1月1日至2012年12月31日间首次进行股权激励草案公告的245家A股上市公司作为研究对象,运用事件研究法对上市公司公告股权激励草案前后的超额收益情况进行检验.研究发现:即使不考虑股权激励本身带来的短期市场效应,草案公告日也更可能出现在股价低点,说明管理层会对草案公告的时机进行选择.进一步的研究则表明管理层是利用了自身对于公司季度盈余报告的信息优势来进行草案公告日的选择. 相似文献
19.
This paper applies contingent claim analysis to value pension contracts for real-life collective pension plans with intergenerational risk sharing and offering DB-like benefits. We rewrite the balance sheet of such a pension fund as an aggregate of embedded generational options. This implies that a pension fund is a zero-sum game in value terms, so any policy change inevitably leads to value transfers between generations. We explore intergenerational value transfers that may arise from a plan redesign or from changes in funding policy and risk sharing rules. We develop a stochastic framework which accounts for time-varying investment opportunities and computes the embedded generational options. Changes in the values of the generational options enable us to evaluate the impact of policy modifications in the pension contract with respect to intergenerational transfers and redistribution. We find that a switch to a less risky asset mix is beneficial to elderly members at the expense of younger members who lose value. A reallocation of risk bearing from a plan with flexible contributions and fixed benefits to a plan with fixed contributions and flexible benefits leads to value redistribution from older plan members to younger ones. 相似文献
20.
Guangming Zhang Stephen C.-Y. Lu 《The Journal of the Operational Research Society》1990,41(5):391-404
Recognising the importance of combining manufacturing and management systems for machining operation planning, this paper presents a new methodology for the evaluation of economic aspects in an operation plan. To ensure that the quality of machined parts satisfies the required specifications, the manufacturing system acts as an alternative generator that provides meaningful and practical plans. Through cost analysis, the variable, fixed, and total costs associated with the machining operation are quantitatively determined. The management system, which functions as an evaluation mechanism, then selects the optimal plan based on the defined goal. The proposed methodology has been applied in the framework design of an expert system. The program establishes a sequence of machining operation planning and searches for the optimal plan. This optimal plan integrates considerations from both managers and production engineers, and balances their needs for efficient machining of a quality product. 相似文献