生物系统冗余结构的Type-2型数学模型

生态系统本身就是一个自组织的进化系统,生物与环境的交流和相互作用中,生物利用自身的冗余结构和冗余补充,使整个系统的进化始终朝着有利于生物发展的方向进化。本文利用Type-2模糊系统建立了生物群落冗余结构的数学模型,提出了生物群落稳定性的度量方法,研究了生物群落冗余结构与生物进化可靠性和稳定性的关系。     

核电厂不可修复系统冗余配置的可靠性参数论证

核电厂为了提高可靠性,大量系统都设置了不同程度的冗余系列,通过对核电厂不可修复系统可靠性参数的推导、定量计算和比较分析,从可靠性理论角度,论证了不同的冗余配置方案导致系统不同平均寿命和可靠性分布,为系统冗余配置方案的选择提供参考.     

卫星和飞船跟踪测控问题的数学模型

针对卫星和飞船跟踪测控的建站问题,基于几何关系和蜂巢式覆盖思想,依据不同情形建立了数学模型,求得实现全程测控时所需最少测控站个数．分析了神舟七号测控站的测控范围．并对模型加以验证．     

基于边际效应分析的防空武器系统可靠性优化研究

针对复杂武器系统可靠性冗余分配优化问题,以系统的可靠度最大为目标函数,综合考虑系统的费用、质量等约束条件,建立了武器系统的可靠性冗余分配最优化模型;提出了基于相对增量的边际效应分析方法的求解算法,通过改进各级子系统的可靠性,从而使总的系统可靠性最大,最后对防空武器系统的可靠性冗余分配优化问题进行了实例分析。     

具有内部构造安全保障体系的冗余机器系统的稳定性及可靠性分析

对具有内部构造安全保障体系的冗余机器系统的渐近稳定性先进行了证明.再对系统解的可靠性作了初步的研究证明.即瞬态可靠性大于等于其牢固可靠性。     

双模冗余非马尔可夫模型可修系统分析

文章采用补充变量, 将双模冗余系统的非马尔可夫模型转化为马尔可夫过程模型, 针对该模型进行可靠性估计, 比较了不计维修时系统的寿命分布, 介绍了快修条件下系统的可靠性工作特点.牵引变压器应用研究表明这种分析方法是十分有效的.     

不确定并串联系统的贮备冗余优化

在可靠性工程中,可靠性优化设计是系统设计阶段需要解决的一个重要问题.文章针对不确定并串联系统,研究了具有不确定寿命和不确定费用的贮备冗余优化问题.以最大化系统可靠性,最大化系统寿命和最小化系统费用为目标,构建了3种不同的贮备冗余优化模型.在不确定理论框架下,给出了3种模型的等价模型,且根据决策者的偏好构建了3种带有优先级的模型.此外,给出的数值算例说明了所构建模型的合理性.     

基于人因可靠性的建筑工程质量管理模型分析

人因可靠性分析是风险分析理论的重要内容,通过对建筑工人的人因可靠性分析,建立了建筑工人人因可靠性数学模型,阐述了人因可靠性对建筑工程质量的影响.为工程管理方提高工程管理水平,避免人为差错影响工程质量提供参考.     

基于可用度的军用飞机可靠性指标确定方法

军用飞机的可靠性是影响军用飞机可用性和战备完好性的重要因素,在飞机研制阶段建立整机可靠性指标参数的数学模型,确定飞机整机可靠性指标,对于飞机的作战使用具有重要意义.提出一种基于可用度的军用飞机可靠性指标确定方法,来计算经常处于使用状态的军用飞机整机可靠性指标值.     

基于无线传感器网络的可靠性模型及上界

无线传感器网络的技术应用与开发对网络的性能要求越来越高.从保证网络可靠性和服务质量角度考虑无线传感器网络性能参数.给出了保障服务质量的网络可靠性数学模型,由于可靠性计算是NP难问题,进一步研究该网络模型的可靠性上界.通过利用点割集代替极小割的方法提出了可靠性上界的计算公式.仿真结果表明,上界结果对评估网络可靠性精确值的近似效果较好.     

考虑n中连续取k失效准则的树状系统可靠性求解方法

树状网络系统在管道运输,网络通信中较为常见,对其进行可靠性评估对系统设计及优化具有重要意义。针对树状冗余系统,在n中连续取k失效准则下,通过有限马尔可夫嵌入法并对其进行变形,研究了树状系统可靠性求解方法。本文对树状系统建模加以定义,提出了基于层数参数,层-节点向量,父-子节点矩阵三元参数的树状系统表示方法,研究了变形有限马尔可夫嵌入法的树状系统n中连续取k失效准则下的可靠性求解方法,给出了三个数值算例应用并分析了算法的运算复杂度。最后,本文对比讨论了基于概率母函数法的树状系统在n中连续取k准则下系统可靠性求解方法的研究,得出结论本文算法针对树状冗余系统n中连续取k失效准则下系统可靠性求解应用范围更广,求解效率较高。     

铁磁性设备补偿磁场的数学模型及其应用

研究用永磁体对铁磁性设备进行磁场补偿的问题,建立了补偿磁场的数学模型.将设备划分成若干个小长方体后,基于磁矩量法建立了数学模型,并对补偿磁场进行拟合.在计算模型中的耦合系数矩阵时,用多个点的平均值作为耦合系数的有效值,提高了计算结果的可靠性和稳定性.并且,针对永磁体距离设备很近时,设备呈现出的非线性磁化特性,通过优化方法求解各个单元的等效磁化率,这种方法不需要知道铁磁材料的磁化曲线和设备结构,便于计算和实际应用.最后,通过实验设计与数值计算,得到了永磁体对设备进行补偿的磁场分布,模型计算结果与实际测量数据误差11%以内,这说明该模型能够满足工业要求,具有实际应用价值.     

Redundant paths and reliability bounds in gamma networks

Multistage Interconnection Networks (MINs) are network systems providing fast and efficient communications at a reasonable cost. A gamma network is a specific class of MINs, which provides redundant paths in the system. In a gamma network, information from source nodes is transmitted through a specific set of routes to destination nodes. Reliability of an MIN is used as a measure of system’s ability to transform information from input to output devices. Due to the complexity of network configuration and availability of redundant paths, reliability bounds to estimate the exact reliability of a gamma network is proposed. A numerical example of an 8 × 8 gamma network is presented to demonstrate the accuracy of the reliability bounds. When the lower bound reliability provides sufficient assurance that the system will be operational at some specified time and closely approximates the exact reliability, then no further effort for obtaining the exact reliability expression is necessary.     

Computing availability for redundant flow systems

There are many papers in the literature about computing reliability for binary redundant systems. However in the real world there are many systems, whose economics depend on average availability of flow throughout the life span of the system rather than reliability on one particular threshold level only. Such systems exist in oil and gas redundant flow networks. To best of this author’s knowledge no attempt has been made yet to compute availability of such systems. Computing availability of flow is of utmost importance for the economical planning and design of any industrial flow networks. In this paper an approach is proposed to compute availability of flow in redundant flow systems. The proposed approach is compared with the approach used in the weighted $k$ -out-of- $n$ systems for computing reliability. The results show the better performance of the proposed approach in terms of computational time if the system bears heavier weights. Furthermore proposed scheme has additional advantage of being capable of handling fractional weights.     

A cross entropy based algorithm for reliability problems

The Cross Entropy method has recently been applied to combinatorial optimization problems with promising results. This paper proposes a Cross Entropy based algorithm for reliability optimization of complex systems, where one wants to maximize the reliability of a system through optimal allocation of redundant components while respecting a set of budget constraints. We illustrate the effectiveness of the proposed algorithm on two classes of problems, software system reliability optimization and complex network reliability optimization, by testing it on instances from the literature as well as on randomly generated large scale instances. Furthermore, we show how a Cross Entropy-based algorithm can be fine-tuned by using a training scheme based upon the Response Surface Methodology. Computational results show the effectiveness as well as the robustness of the algorithm on different classes of problems.     

冷储备可修系统的一个模型及其经济分析

本文研究修理工可对系统外顾客服务的两部件冷储备可修系统，利用向量Markov过程方法，求出了系统的可靠性指标，并且进行了经济分析．     

矿井复杂通风系统技术改造方案的优选

结合实例对矿井复杂通风系统技术改造方案进行了优选,用ＶｉｓｕａｌＢａｓｉｃ３．０ 编制了在Ｗｉｎｄｏｗ ｓ 下运行的计算机程序,该程序具有算法先进、收敛速度快、可靠性好、适用广和使用方便等优点。对矿井日常通风管理和通风长远规划也具有指导意义     

基于可靠性弹性指标的系统弹性度量方法

为深入研究系统弹性问题,首先分析系统中不同节点和边的可靠性弹性指标。通过引入节点弹性与边弹性,并考虑节点弹性与边弹性二者的联系以及对系统弹性的影响,建立了能够反映系统拓扑结构变化的弹性度量方法模型。最后,在对弹性度量方法的验证环节中,引入了具有分层特性的交通系统,按照所述弹性度量方法对分层交通系统中的节点弹性以及边弹性进行了分析,发现该种分层交通系统的整体弹性程度一般,任何小的干扰或者故障都有可能造成该交通系统拥堵或瘫痪。     

Bounds of redundant multicast routing problem with SRLG-diverse constraints: edge,path and tree models

This paper proposes three classes of alternative mathematical programming models (i.e., edge-based, path-based, and tree-based) for redundant multicast routing problem with shared risk link group (SRLG)-diverse constraints (RMR-SRLGD). The goal of RMR-SRLGD problem is to find two redundant multicast trees, each from one of the two sources to every destination, at a minimum cost while ensuring the paths from the two sources to a destination do not share any common risks. Such risk could cause the failures of multiple links simultaneously. Therefore, the RMR-SRLGD problem ensures the availability and reliability of multicast services. We investigated and compared the theoretical bounds of the linear programming (LP) relaxation for all models. We also summarized a hierarchy relationship of the tightness of LP bounds for the proposed models.     

Performance assessment and reliability analysis of dependable and distributed computing systems based on BDD and recursive merge

System reliability evaluation, sensitivity analysis, failure frequency analysis, importance measures, and optimal design are important issues that have become research topics for distributed dependable computing. Finding all of the Minimal File Spanning Trees (MFST) and avoiding repeatedly computing the redundant MFSTs have been key techniques for evaluating the reliability of a distributed computing system (DCS) in previous works. However, identifying all of the disjointed MFSTs is difficult and time consuming for large-scale networks. Although existing algorithms have been demonstrated to work well on medium-scale networks, they have two inherent drawbacks. First, they do not support efficient manipulation of Boolean algebra. The sum-of-disjoint-products method used by these algorithms is inefficient when dealing with large Boolean functions. Second, the tree-based partitioning algorithm does not merge isomorphic sub-problems, and therefore, redundant computations cannot be avoided. In this paper, we propose a new efficient algorithm for the reliability evaluation of a DCS based on the recursive merge and the binary decision diagram (BDD). Using the BDD substitution method, we can easily apply our algorithm to a network with imperfect nodes. The experimental results show a significant improvement in the execution time compared to previous works.