装备多寿命指标变量现场数据的可靠性分析

在装备使用保障阶段,对于可由多个寿命指标衡量和控制的装备系统,其可靠性评估及维修保障策略制定都具有重要的工程应用价值.通过对飞机寿命指标不同形式的分析,建立了时间特征与使用特征寿命相关时装备系统多寿命指标变量联合可靠性评估模型,并通过实例对比研究,在评估方法的实用性和有效性等方面均有所改进,为装备多寿命指标变量现场可靠性评估提供了一种方法.     

考虑传输容量的通信网端到端可靠性指标算法

归一化传输容量加权通信网端到端可靠性指标,非常适合评价现代高速宽带通信网络.然而计算全过程易于在计算机上编程实现的算法尚未见到.研究出一整套可靠性指标的计算方法.由于,从路由计算、不交化网络状态集及其对应容量的求取,到最后获得可靠性指标结果等各个环节,均实现了代数化或逻辑代数化运算,因此,整套算法易于编写计算机程序.详细介绍了算法各环节的计算规则与步骤,并对正确性与合理性进行了论证.通过举例详细说明算法的计算过程,并检验算法的正确性.     

基于预期方案求解多属性决策问题的新方法研究

章提出了基于预期方案求解多属性决策问题的一种新方法。该方法基于预期方案，利用指数效用曲线拟合指标数据，通过定义的偏差测度和指标一致度来确定相应的指标权重，最后通过动态调整预期方案进行多属性综合评价。     

应用Sugeno模糊积分的目标识别效果评估

针对目标识别效果评估，提出一种通用化的评估思路，选取了评估指标及测度方法。随后，构筑了基于模糊积分的目标识别效果评估模型。最后，结合实测数据和拟合数据完成了仿真。     

考虑全局风险均衡度的电力通信网最优安全链路选择方法

在智能电网环境下,电力通信网全新的运行管理模式需要系统间频繁的进行工作协同和业务传递,产生了信息传输链路选择的风险问题.因此,研究如何降低电力通信网业务通道风险,设计最优的通信业务安全链路选择方法,已成为领域内研究的热点问题.提出了一种新的考虑全局风险均衡度的电力通信网最优安全链路选择方法,即考虑了传输链路的最短性,又根据业务重要级别兼顾了路由选择的安全性.首先,给出了电力通信网业务安全链路选择模型,对业务安全链路选择问题进行了描述和数学建模;然后,采用模糊层次分析法(FAHP)构建了业务重要度评价和排序模型;最后,利用改进的迪杰斯特拉(Di.jkstra)算法和粒子群优化(PSO)算法对多目标优化问题进行了求解,计算出最优安全链路.仿真实验结果表明,所提方法可有效降低电力通信网的全局风险,具有一定的可用性和实效性.     

基于GAHP和云模型的军事组织安全文化评价方法

安全文化评价是军事组织安全文化建设进行协调、控制的重要环节.为实现军事组织安全文化的定量评价,分析了军事组织安全文化的特点,根据SMART原则建立了科学的评价指标体系,提出了一种基于群组层次分析法(GAHP)和云模型的安全文化评价方法.综合多名专家意见,利用群组层次分析法来确定各级指标权重,得出各指标的重要性度量,基于云模型实现评价主体的模糊语义性评价与定量评分的双向映射,并通过聚合计算得到综合评价结果.实例分析表明,所提算法具有较好的实用性和适用性,为客观评估军事组织安全文化建设水平提供了可行手段.     

质量评价的属性数学模型和模糊数学模型

本文提出了质量评价的属性数学模型。该模型由三部分组成：单指标属性测度分析，多指标综合属性测度分析，属性识别分析。我们分析了属性数学模型和模糊数学模型的差异。应用例子表明属性数学模型是更合理的     

基于RST/IAHP的航空维修人因可靠性评估模型研究

针对航空维修人因可靠性定量评估这一难点问题,提出了一种基于粗糙集理论(RST)和区间层次分析法(IAHP)的人因可靠性评估模型.根据大量统计数据,运用决策树法建立分层次的航空维修科目人因可靠性指标评价体系.综合采用区间层次分析法和粗糙集方法确定指标权重,提出了采用区间型加权算法对指标进行聚合.以某航空维修系统更换发动机科目为例,对所提方法进行案例验证.结果表明,该方法具有实用、可操作性强等特点,为航空维修系统科目的人因可靠性评估提供了理论参考.     

模糊灰色关联法在大牛地气田优选压裂井层中的应用

压裂是油气田开发的重要增产措施,选择合适的井层进行压裂至关重要.压裂选井时需要综合考虑多种不同的因素,而且各因素在不同程度上影响压裂效果,因素间又相互影响关联.为优选适宜压裂的井,运用灰色关联法综合考虑11种因素,用效果测度函数进行无量纲化,层次分析法求取因素权重,最后以带权的灰色关联度指标优选压裂井.通过实例验证了方法的可靠性与适用性,且计算简单,可指导压裂选井工作,并具有可推广性.     

基于组合赋权法和未确知测度模型的发动机健康状况评估

为了有效评估航空发动机的健康状况,提出一种逼近理想点的组合赋权法和未确知测度模型相结合的评估方法。首先,分别利用序关系分析法、指标相关性赋权法和指标难度赋权法得到各指标的主客观单一权重;利用逼近理想点的组合赋权法并考虑指标权重与重要性的一致性,求解指标组合权重,使赋权结果更具科学性,加大不同类别评价对象的区分度。其次,基于未确知测度模型,利用K-means算法将各指标分为两个对立等级,每个等级又分为两个互补小等级,以减少信息的重叠进一步区分不同类别的评价对象;根据指标属于不同等级的未确知测度、指标组合权重和评分准则,得到评价对象的健康评分。最后,通过航空发动机实例分析以及与其他方法的对比分析,验证此方法的有效性。     

基于改进PSO-BP神经网络的贮存可靠性预测

贮存可靠性是军事储备质量监测的重要环节,科学准确地预测贮存可靠度是现代化军事评估的必然要求。针对历史贮存数据,建立可靠度与年限的贮存可靠性预测模型,采用进化策略改进粒子群算法(PSO)优化BP神经网络进行贮存可靠性预测。通过数据扩充提高样本质量和数量,应用改进后的PSO算法优化BP神经网络的初始权值和阈值,提高网络的泛化能力。PSO算法较好的全局搜索能力与BP网络很强的局部搜索能力相结合,能够避免早熟现象,提高算法的收敛速度及预测精度。实验结果表明,改进的PSO-BP网络模型比PSO-BP和BP神经网络获得更好的预测性能。     

A cross entropy approach to design of reliable networks

One of the most important parameters determining the performance of communication networks is network reliability. The network reliability strongly depends on not only topological layout of the communication networks but also reliability and availability of the communication facilities. The selection of optimal network topology is an NP-hard problem so that computation time of enumeration-based methods grows exponentially with network size. This paper presents a new solution approach based on cross-entropy method, called NCE, to design of communication networks. The design problem is to find a network topology with minimum cost such that all-terminal reliability is not less than a given level of reliability. To investigate the effectiveness of the proposed NCE, comparisons with other heuristic approaches given in the literature for the design problem are carried out in a three-stage experimental study. Computational results show that NCE is an effective heuristic approach to design of reliable networks.     

供应链网络可靠性的多层Bayes估计模型

对供应链网络可靠性进行界定和分析,以节点企业间的协同为基础,得到可靠度计算模型,以此为依据采集实证样本无失效运行的数据.根据供应链网络可靠性统计特性,建立一种多层Bayes估计方法,应用于样本可靠性评估中.在估计失效率的基础上,对供应链网络可靠度进行估计,对仿真结果进行分析,显示多层Bayes估计方法应用效果较好,精确度高,反映了参数不确定性对供应链网络可靠性的影响,能够较好地解决依据无失效数据判定供应链网络可靠性水平的问题.     

上市公司经营业绩的时序多指标综合评价

本文首先指出了传统的静态多指标综合评价的缺陷,在考虑上市公司静态业绩评价和评价值增长变化两方面的基础上,提出了应用主成分分析和理想点法等构造的时序多指标综合评价方法,最后通过电力类上市公司的动态综合评价说明了该方法确实是一种有效的动态评价方法。     

机械产品设计方案的模糊综合评价

本文论述了机械产品设计方案的模糊综合评价总是讨论了评价指标体系的确定及其结构，提出了用于机械产品设计方案评价的多目标多级模糊综合评价模型。     

A self-tuning heuristic for the design of communication networks

This paper addresses the design of communication networks that has a large application area. The problem is to design a minimum cost network subject to a given reliability level. Complexity of the problem is twofold: (1) finding a minimum-cost network topology that every pair of nodes can communicate with each other and (2) computing overall reliability to provide the reliability constraint. Over the last two decades, metaheuristic algorithms have been widely applied to solve this problem due to its NP-hardness. In this study, a self-tuning heuristic (STH), which is a new approach free from parameter tuning, is applied to the design of communication networks. Extensive computational results confirm that STH generates superior solutions to the problem in comparison to some well-known local search metaheuristics, and also more sophisticated metaheuristics proposed in the literature. The practical advantage of STH lies in both its effectiveness and simplicity in application to the design problem.     

综合评价方法在NBA赛程分析中的应用

随着认知领域的不断扩大,人们所面临的评价对象日益复杂,综合评价问题得到广泛应用.针对高职类学生知识结构特点,主要介绍层次分析法及模糊综合评价法在建模培训中的应用.在实践中,通过抓住确定影响因素指标体系及确定各指标权重这两个关键环节,把握各种具体的综合评价方法的主体思想.针对08年全国大学生数学建模竞赛D题(NBA赛程分析与评价),介绍赛程评价方法及赛程安排的0-1规划模型.     

Framework for link reliability in inter-working multi-hop wireless networks

With the increase in deployment of multi-hop wireless networks and the desire for seamless internet access through ubiquitous connectivity, the inter-working of heterogeneous multi-hop wireless networks will become prominent in the near future. To complement the quest for ubiquitous service access, multi-mode mobile terminals are now in existence. Inter-working heterogeneous multi-hop wireless networks can provide seamless connectivity for such multi-mode nodes but introduces a number of challenges due to its dynamic network topology. One of the challenges in ensuring seamless access to service through these terminals in an inter-working environment is the selection of reliable wireless point-to-point links by the multi-hop nodes. A wireless link is said to be reliable if its radio attribute satisfies the minimum requirements for successful communication. Successful communication is specified by metrics such as signal to interference and noise ratio (SINR), probability of bit error etc. However, the multi-hop wireless networks being inter-worked may operate with different link layer protocols. Therefore, how can the reliability of a wireless link be estimated irrespective of the link level technologies implemented in the networks being inter-worked so that optimal paths can be used for multi-hopping between nodes? In this paper, a generic framework which can estimate the reliability of a link in inter-working multi-hop wireless network is presented. The framework uses the relationship between inter-node interference, SINR and the probability of bit error to determine the reliability of a wireless link between two nodes. There is a threshold for the probability of bit error on a link for the link to be termed reliable. Using parameters such as the SINR threshold, nodes’ transmission power, link distance and interfering node density, the framework can evaluate the reliability of a link in an inter-working multi-hop network.     

Practical sequential bounds for approximating two-terminal reliability

With increasing emphases on better and more reliable services, network systems have incorporated reliability analysis as an integral part in their planning, design and operation. This article first presents a simple exact decomposition algorithm for computing the NP-hard two-terminal reliability, which measures the probability of successful communication from specified source node to sink node in the network. Then a practical bounding algorithm, which is indispensable for large networks, is presented by modifying the exact algorithm for obtaining sequential lower and upper bounds on two-terminal reliability. Based on randomly generated large networks, computational experiments are conducted to compare the proposed algorithm to the well-known and widely used edge-packing approximation model and to explore the performance of the proposed bounding algorithm. Computational results reveal that the proposed bounding algorithm is superior to the edge-packing model, and the trade-off of accuracy for execution time ensures that an exact difference between upper and lower bounds on two-terminal reliability can be obtained within an acceptable time.