大口径机枪弹性枪架稳定性分析的冲量法

大口径机枪在弹性枪架上射击稳定性的问题,是影响连发射击精度的一个重要问题,按传统方法以最大后座力或自动机后座到位的瞬间作用校核稳定性,其结果与实际射击现象不符。本文在分析大量实验现象后,提出稳定性分析计算中的冲量法,并以12.7mm 大口径机枪为例进行检验,结果与实验现象相符.     

某舰炮驻退复进机的液压阻力公式

某舰炮驻退复进机为液体气压式复进机,结构较复杂。特别是在复进运动过程中,由于某单向阀打开,使液体流动构成一差动连接回路。本文推导了该舰炮后座和复进过程的液压阻力公式,为对该炮进行反面设计提供了必要的技术储备。     

内弹道多通道实验数据处理方法研究

本文对内弹道多通道实验曲线的处理方法进行了较为详细的分析.充分利用多通道实验数据,得出了弹丸运动规律、弹底压力变化规律、平均压力变化规律.为进一步认识膛内现象奠定了一定的基础.     

一种基于统计参数映射融合独立成分分析的新的激活区探测方法

统计参数映射在某种程度上依赖于广义线性模型和高斯场理论。广义线性模型的缺陷在于这些假设不能很好地表示fMRI数据,并且脑活动分布模式和血液动力学模型也不能由广义线性模型回归方程来恰如其分地模拟。而独立成分分析不能够提供每一独立成分激活区的显著性估计,这使得实验者不能够很好地解释所获得的结果。提出一种将SPM和ICA技术进行融合的方法,此方法可以将ICA自身的某些优势和GLM的假设检验方法结合起来,互相取长补短。实验结果证明了这种方法在探测由运动任务所产生的激活区方面是有效的。     

一种多通道武器控制台的可靠性预计分析

对设计的一种多通道武器控制台的可靠性进行了预估分析.采用元器件计数法和元器件应力分析法,得出了模块级的失效率.按照系统串联结构的可靠性框图,计算出系统的失效率、平均无故障工作时间等可靠性指标.结果表明,预计值满足了系统规定的使用要求.     

基于集对分析的战场态势分析模型

在防空作战中,战场态势的分析非常重要,它是辅助决策的基础.针对战场态势的问题,以集对分析的同异反联系度和距离测度为基础,构造了战场态势的分析模型,进行了深入探讨.最后,通过实例计算表明了分析模型对于评估战场态势的可行性和有效性.     

信息管理误失灰色补偿方法

在信息采集、信息管理、信息传递过程中,数据链出现空穴、误传或丢失等情况时,将影响信息采集传递的安全性与信息管理的有效性,是信息管理与使用中一个值得关注的问题,如何对数据列进行有效补偿则是解决该问题的关键.运用灰色理论与正交试验设计方法建立了信息链缺失补偿模型并给出了信息链空穴补偿优化准则.所给出的具体的补偿实例说明信息链空穴灰色生成与正交试验设计生成是一种极为有效的信息缺失补偿方法.     

退化速率跟踪粒子滤波在剩余使用寿命预测中的应用

毋庸置疑,剩余使用寿命预测对于设备的健康管理越来越重要。近年来粒子滤波方法被越来越多地应用到设备寿命预测技术当中,这是因为粒子滤波方法能更好地解决非线性非高斯系统滤波问题,而且能够获得不确定度信息。但该方法的预测性能却过度依赖于预测模型,并且对于模型参数的初始分布也比较敏感,这在一定程度上限制了粒子滤波预测方法的进一步发展。针对基本粒子滤波预测方法的不足,提出了一种基于退化速率跟踪粒子滤波的通用预测框架,以历史观测数据的退化速率统计规律作为指导来跟踪目标数据的退化速率,实现对粒子滤波预测方法的简化,并将该方法用于轴承和锂离子电池的剩余使用寿命预测,验证了方法的有效性。     

Probabilistic analysis of an asymptotically optimal solution for the completion time variance problem

Scheduling a set of n jobs on a single machine so as to minimize the completion time variance is a well‐known NP‐hard problem. In this paper, we propose a sequence, which can be constructed in O(n log n) time, as a solution for the problem. Our primary concern is to establish the asymptotical optimality of the sequence within the framework of probabilistic analysis. Our main result is that, when the processing times are randomly and independently drawn from the same uniform distribution, the sequence is asymptotically optimal in the sense that its relative error converges to zero in probability as n increases. Other theoretical results are also derived, including: (i) When the processing times follow a symmetric structure, the problem has 2^{⌊(n−1)/2⌋} optimal sequences, which include our proposed sequence and other heuristic sequences suggested in the literature; and (ii) when these 2^{⌊(n−1)/2⌋} sequences are used as approximate solutions for a general problem, our proposed sequence yields the best approximation (in an average sense) while another sequence, which is commonly believed to be a good approximation in the literature, is interestingly the worst. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 373–398, 1999     

Efficient multinomial selection in simulation

Consider a simulation experiment consisting of v independent vector replications across k systems, where in any given replication one system is selected as the best performer (i.e., it wins). Each system has an unknown constant probability of winning in any replication and the numbers of wins for the individual systems follow a multinomial distribution. The classical multinomial selection procedure of Bechhofer, Elmaghraby, and Morse (Procedure BEM) prescribes a minimum number of replications, denoted as v*, so that the probability of correctly selecting the true best system (PCS) meets or exceeds a prespecified probability. Assuming that larger is better, Procedure BEM selects as best the system having the largest value of the performance measure in more replications than any other system. We use these same v* replications across k systems to form (v*)^k pseudoreplications that contain one observation from each system, and develop Procedure AVC (All Vector Comparisons) to achieve a higher PCS than with Procedure BEM. For specific small-sample cases and via a large-sample approximation we show that the PCS with Procedure AVC exceeds the PCS with Procedure BEM. We also show that with Procedure AVC we achieve a given PCS with a smaller v than the v* required with Procedure BEM. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 459–482, 1998