线性回归模型系数Stein估计的改进研究

针对线性回归模型病态的根本原因,提出了一类新的估计———c-k型估计,将岭估计与Stein估计统一到一个估计类;研究了这一估计类,证明利用岭回归技术可以改进著名的Stein估计(在均方误差意义下);同时研究了相应参数的最优值,分别给出了它的一个上界及下界,为病态线性回归模型系数的有偏估计提供了改进的技术途径.     

基于ML-Ⅱ的指数分布可靠性多层Bayes估计

Bayes估计法是可靠性评估中应用最为广泛的方法之一,指数分布的Bayes验前概率密度函数中的重要参数主要依靠Reformulation法和Box-Tiao法确定,具有较强的主观经验性。基于Beyes估计的基本思想,以试验数据为依据,利用第二类极大似然估计法(ML-Ⅱ估计法)确定Bayes方法中的相关参数,避免了参数确定的主观性。实例表明结果合理,方法客观、可行。     

一种波束内目标与诱饵 DOA联合估计新方法

拖曳式诱饵干扰下目标和诱饵DOA参数的准确估计是导引头实现目标分选的前提条件。波束内目标和诱饵的存在引起雷达回波混叠和观测耦合,导致常规观测提取与参数测量方法失效。通过挖掘雷达接收回波和、差通道信号条件概率分布协方差所包含的未知参数信息,获得了目标和诱饵DOA估计的解析表达式,针对估计求解中所需相对功率比未知的情况,提出了基于干扰检测、雷达测量与目标跟踪信息辅助循环估计相对功率比的DOA二次联合估计方法。不同干扰条件的仿真实验验证了估计方法的有效性。     

履带车辆转向过程循环功率分析

针对差速式、独立式2类转向机构,分别给出了不计和计及履带接地段打滑条件下最大循环功率及相应的相对转向半径的计算方法,定量讨论了不计和计及履带接地段打滑时循环功率的差别。在示例给定的计算条件下计算结果表明,计及履带接地段打滑时循环功率较不计打滑时小约20％。实车试验结果证实:考虑履带接地段打滑计算的循环功率同实际值更接近,在分析循环功率时不能忽略履带接地段的打滑。     

Single machine sequencing with linear models of release dates

The paper deals with a problem of scheduling a set of jobs on a single machine. Before a job is released for processing, it must undergo some preprocessing treatment that consumes resources. It is assumed that the release date of a job is a linear decreasing continuous function of the amount of a locally and globally constrained, continuously divisible resource (e.g., energy, catalyzer, financial outlay, gas). The problem is to find a sequence of jobs and a resource allocation that will minimize the maximum job completion time. Such a problem appears, for example, in the ingot preheating and hot-rolling process in steel mills. It is shown that the problem is strongly NP-hard. Some polynomially solvable cases of the problem and approximate algorithms with both experimental and worst-case analysis are presented. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 99–113, 1998     

On lifetimes in random environments

For a component operating in random environment, whose hazard rate is assumed to be the realization of a suitable increasing stochastic process, conditions are found such that its lifetime is increasing in likelihood ratio (ILR). For the lifetimes of two components of the same kind some comparisons based on partial stochastic orders are presented. Some applications to the case of repairable components are finally provided. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 365–375, 1998     

Stage life testing

In progressive censoring, items are removed at certain times during the life test. Commonly, it is assumed that the removed items are used for further testing. In order to take into account information about these additional testing in inferential procedures, we propose a two‐step model of stage life testing with one fixed stage‐change time which incorporates information about both the removed items (further tested under different conditions) and those remaining in the current life test. We show that some marginal distributions in our model correspond either to progressive censoring with a fixed censoring time or to a simple‐step stress model. Furthermore, assuming a cumulative exposure model, we establish exact inferential results for the distribution parameters when the lifetimes are exponentially distributed. An extension to Weibull distributed lifetimes is also discussed.     

关于U算子有界性的证明

利用Hardy Littlewood极大算子及性质与分数次极大算子及性质 ,证明了u(x)在Lq(Rn) ,L∝ ,Lq(E)空间上是有界的 ,Coσoπeβ定理应予以推广。     

Iterative coloring extension of a maximum clique

In this paper we present an improved branch and bound algorithm for the vertex coloring problem. The idea is to try to extend the coloring of a maximum clique to its adjacent vertices. If this succeeds, its successive neighbors are considered; in case of failure (i.e., in the case the initial colors are not sufficient), working on the subgraph induced by the maximum clique and its neighborhood, the lower bound is improved by seeking for an optimal coloring of this subgraph by branch and bound. The process is repeated iteratively until the whole graph is examined. The iterative scheme exploits a further lower bound obtained by integrating a simple algorithm into the maximum clique search, and a new method to compute upper bounds on subgraphs. Furthermore, a new branching rule and a method for the selection of the initial maximum clique are presented. Extensive computational results and comparisons with existing exact coloring algorithms on random graphs and benchmarks are given. © 2001 John Wiley & Sons, Inc. Naval Research Logistic 48: 518–550, 2001     

坦克火控首发命中率试验脱靶弹数据处理方法

通过对出现脱靶弹情况下的散布特征参数估计方法的研究 ,建立了正态双边截尾样本均值和方差估计数学模型 ,并给出了数值计算方法 ,为坦克火控系统首发命中概率试验脱靶弹数据处理提供了理论依据。