基于贝叶斯网络的认知引擎设计与重配置

以往的通信行为指导系统未来通信, 以满足用户需求并适应环境变化, 是认知无线电系统的核心所在, 为此提出了一种基于贝叶斯网络的认知引擎, 用于解决在复杂多变的电磁环境与用户需求条件下, 认知无线电系统参数自适应调整的问题. 通过对系统过去通信行为样本数据, 进行结构学习和参数学习建立认知引擎, 将系统当前环境状态和用户需求信息经预处理作为推理的证据, 应用引擎决策出系统此时最佳的工作参数, 完成系统参数重构. 本文利用OPNET工具建立一个移动无线网络完成仿真实验, 仿真结果表明该认知引擎能有效地使移动无线网络适应环境变化, 改善端到端通信性能, 进一步验证了建模方法的可行性.     

外场可更换模块体系下测试性验证试验发展研究

以外场可更换模块(LRM)为基本组成单元的综合模块化系统已成为现代军用装备电子系统的发展趋势。LRM是装备二级维修保障体系的关键技术之一,其测试性是实施装备二级维修保障体系的关键因素,在LRM的生产定型阶段对其进行测试性验证试验具有很大必要性。目前国内外并没有专门针对LRM体系的测试性验证试验研究。文中对LRM体系下测试性验证试验实施的相关技术研究现状进行了总结,指出了LRM在电气和机械方面的特性对LRM体系下进行测试性验证试验造成的不利影响,并对这一领域进一步研究的关键技术和发展方向进行了展望。     

非平稳随机激励下结构体系动力可靠度时域解法

将结构动力方程写成状态方程形式,采用精细积分法对其进行数值求解,导出了非平稳激励下结构随机响应的时域显式表达式,该过程的计算量仅相当于两次确定性时程分析的计算量. 基于该显式表达式,结合首次超越失效准则,提出了非平稳随机激励下结构体系动力可靠度的数值模拟算法. 与功率谱方法相比,该方法无需同时在时频域内进行大量数值积分,也无需引入关于响应过程跨越界限次数概率分布, 以及各失效模式相关性等方面的假定. 通过数值算例, 对比了该方法与泊松过程法、马尔可夫过程法、传统蒙特卡罗法的计算精度和计算效率,结果显示该方法具有理想的精度和相当高的效率.      

Scale shifting laws from pico to macro in consecutive segments by use of transitional functions

Systems with parts that vary in size from pico to macro inclusive are vulnerable of being incapacitated when a single part fails owing to deterioration of material properties. The majority of system failure can be attributed to incompatibility of integrated parts that were designed individually for general purpose. Total reliability calls for all parts, small and large, to be compatible in life spans. Mass, when regarded as energized matter, can vary as a function of time. This, in retrospect, explains why non-equilibrium and non-homogeneity cannot be avoided for multiscale shifting laws. A consistent and scale invariant definition of energy dissipation gives rise to mass pulsation, a common mechanism that seems to be applicable to living and non-living organisms.Scale shifting laws are developed from the use of transitional functions that stand for the mass ratios related to absorption energies and dissipation energies . The notations j and j + 1 stand for two successive scales: pi-na, na-mi, and mi-ma. Hence, the mass ratios , and can be referred to as the transitional inhomogeneity coefficients. They make up the scale shifting laws . Connection of the accelerated test data at the different scales, say from pico to nano to micro to macro, can be made by application of the definition of a scale invariant energy density dissipation function.On physical grounds, the segmented non-equilibrium and non-homogeneous test data can be connected through a velocity dependent mass and energy relation. Energy and power efficiency are defined to explore the macroscopic experiences to those at the lower scales. The time evolution properties of the material can also be derived as a package to include the accelerated test data, a procedure normally referred to as validation. The separation of derive-first and test-later, can never be abridged without ambiguities. Hence, total reliability of a system with many parts is advocated by judiciously matching the nine primary variables consisting of the initial disorder sizes, the time rates, and increments of the absorbed and dissipated energy density. The nine controllable variables consisting of life span distribution, energy, and power efficiencies for the three scale ranges are of secondary consideration.     

Advanced method to estimate reliability-based sensitivity of mechanical components with strongly nonlinear performance function

Based on the random perturbation technique for reliability sensitivity design,some realistic reliability-based sensitivity issues are discussed,some of which have a structure of high nonlinear performance functions.Combining the related theories of the moment method of the reliability analysis,the matrix differential,and the Kronecker algebra,the reliability-based sensitivity method based on the perturbation method is modified if the first four moments of random variables are given.Meanwhile,a reliability-based sensitivity computation method is proposed.Some examples are used to show that using this method can effectively improve the accuracy of the reliability-based sensitivity computation and offer a reliable theoretic basis in engineering.     

成败型元件可靠性估计及近似置信限

本文基于成败型元件串联系统的成败型试验数据,研究成败型元件可靠性的点估计以及近似置信下限.     

无失效数据情形参数的综合估计

本对指数分布的无失效数据,在引进失效信息后,在先验分布为Gamma分布时,给出了失效率的多层Bayes估计和综合Bayes估计,并给出了无失效数据情形可靠度的综合估计,还结合实际问题进行了计算。     

工程结构的余度衡准及发展

近年来发生的许多事故表明,按传统方法设计和评定工程结构不能保证其损伤后的安全性,人们试图引入新的余度衡准来解决这一问题．余度密准的概念和定义十分繁杂,并且还在不断发展之中,本文给出了余度的定义,对各种分度衡准进行了归纳分类,评述和研究了它们的特点及应用,并讨论了与余度相关的几个概念．     

二项分布无失效数据可靠度的多层Bayes估计

文章对二次分布无失效数据的可靠度,在先验分布为Ｂｅｔａ分布时,给出了可靠度的多层Ｂａｙｅｓ估计。最后,结合实际问题进行了计算。     

双冗余通讯网络的可靠性分析与模型

在工业测控通讯网络单系统可靠性数学模型的基础上,针对重要测控领域中常用的双冗余通讯网建立其可靠性数学模型,并提出了双冗余网的可靠性分析方法