On the behavior and shape of mixture failure rates from a family of IFR Weibull distributions

Populations of many types of component are heterogeneous and often consist of a small number of different subpopulations. This is called a mixture and it arises in a number of situations. For example, a majority of products in industrial populations are mixtures of defective items with shorter lifetimes and standard items with longer lifetimes. It is a well‐known result that distributions with decreasing failure rates are closed under mixture. However, mixtures of distributions with increasing failure rates are not easily classifiable. If the subpopulations involved in the mixture have increasing failure rates, there might be some upward movement in the mixture and later a general downward pull towards the strongest component. Little work has been done in describing the shape of mixture failure rates when all subpopulations do not have decreasing failure rate. In this paper, we present general results that describe the shape and behavior of a failure rate of a mixture obtained from two Weibull subpopulations with strictly increasing failure rates. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

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A critical look at the U.S. deceased‐donor organ procurement and utilization system

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激光辐照下45#钢板响应特性

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针对被动声纳信号的特点,提出了基于信号线谱特征的主成分分析(PCA)特征选择方法,其优点是从复杂的目标信号中提取目标的特有信息,降低了目标特征维数.将此方法用于实录的三类水下目标数据,采用BP神经网络对目标进行识别分类,仿真结果说明了所提出的方法的正确性和有效性.     

小样本三维正态分布整体检验射击精度方法研究

讨论了小样本三维同方差正态分布整体检验射击精度问题.给出了n=3,4,5的不同显著水平α的检验OC曲线.计算出了与第一类错误和第二类错误相联系的有关重要物理参数.模拟表明该方法检验效果良好.     

编队对地攻击联合火力分配问题的Swt-opt算法

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