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31.
航天发射试验安全评价中涉及众多风险指标,各指标的选取是否合理,将直接影响安全评估的结果。采用层次分析法对影响航天发射试验安全的设备操作人员评估指标体系进行权重确定,并对评估指标进行了重要性检验,删除相对不重要的指标。采用主成分分析法与聚类分析法结合的方式解决指标之间存在信息重叠且具有一定相关性的问题,实现了指标体系的优化。 相似文献
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Laser beam weld-metal microstructure in a yttrium modified directionally solidified Ni3Al-base alloy
The microstructure of laser beam weld-metal of an yttrium doped directionally solidified alloy IC 6A, with chemical composition Ni–16Al–8.5Mo–0.12B–0.05C–0.03Y (at.%) was studied. The dendritic microsegregation observed within the fusion zone indicated that dendrite cores were slightly depleted in molybdenum and aluminum and the interdendritic regions were also considerably enriched in yttrium. Severe cracking in the weld-metal was observed and was found to be closely associated with interdendritic eutectic-type microconstituents identified as consisting of γ, γ′ and Ni–Mo phases. An yttrium-rich phase (Ni3Y) was observed in some interdendritic regions containing the eutectic γ, γ′ and Ni–Mo products. Their formation was discussed in relation to plausible microsegregation induced alteration of primary solidification path during cooling from welding temperatures. 相似文献
34.
针对群决策偏好集结中违反Pareto 最优性的情况, 设计一种基于群组判断几何离差的同质性集结方法. 该方法在集结前进行几何离差测试, 以确定个体决策信息的离差水平. 离差较小时, 可基于几何平均集结; 对于离差较大且修正复杂度较高的决策信息, 采用主成分分析(PCA) 从高维决策信息中提取大多数相关信息, 在不依赖主观分析的情况下进行加权集结. 仿真实验表明, 所提出的方法能够在不违背Pareto 最优性的基础上集结离差较大的群决策信息.
相似文献35.
为提高二值连通域标记的速度,将地址-事件表示AER(Address Event Representation)思想引入到二值图像处理,提出了一种基于事件对等价标号的二值连通域标记方法。该算法无需多次遍历图像中的背景点和冗余目标点,首先将待标记的连通域以AER“事件对”的方式编码保存,通过“事件对”的遍历生成临时标号和等价标记表;然后根据等价表修改临时标号;完成标号映射后最终实现连通域标记。整个算法只处理极低冗余的事件信息,避免了对全图像素的重复扫描与处理。实验结果表明,图像以AER“事件对”方式存储,数据量仅为全帧图像的10%~35%,有较高的压缩比;且该算法速度快,可达到了传统基于等价标号算法的1.5~8倍。 相似文献
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In this paper, a novel framework for networked estimation of multi‐agent systems subject to presence of actuator faults is proposed. This framework is developed based on the notion of sub‐observers where within a group of sub‐observers each sub‐observer estimates certain states that are conditioned on a given input, output, and other state information. We model the overall estimation process by a weighted estimation (WE) digraph. By selecting an appropriate path in the WE digraph, an assigned supervisor can select and configure a set of sub‐observers to successfully estimate all the system states. In the presence of large intermittent disturbances, noise, and faults certain sub‐observers may become invalid, and consequently the supervisor reconfigures the set of sub‐observers by selecting a new path in the estimation digraph such that the impacts of these uncertainties are confined to only the local estimators. This will prevent the propagation of uncertainties on the estimation performance of the entire multi‐agent system. Simulation results provided for a five satellite formation flight system in deep space confirm the validity and applicability of our proposed analytical work. 相似文献
38.
A novel parametric modeling technique is proposed to develop combined neural network and transfer function models for both time and frequency (TF) domain applications of passive components, where the neural network is trained to map geometrical variables to the coefficients of transfer functions. Built on our previous work, a new order‐changing module is developed to enforce stability of transfer functions and simultaneously guarantee continuity of coefficients. A constrained optimization strategy is introduced to enforce passivity of transfer functions through a neural network training process. A general equivalent circuit for two‐port passive components is generated directly from coefficients of arbitrary‐order transfer functions. Once trained, the parametric model can provide accurate and fast prediction of the electromagnetic behavior of passive components with geometrical parameters as variables. Compared to our previous work, the proposed method enables models to work well in the time domain providing good accuracy in challenging modeling applications. Two parametric modeling examples of spiral inductors and interdigital capacitors, and their application in both time and frequency domain simulations of a power amplifier are examined to demonstrate the validity of the proposed technique. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2013. 相似文献
39.
以往智能终端机只是利用于卷烟销售方面,用于专卖工作的还不曾提及,是行业的盲点。基于3G网络的专卖移动办公平台以IMS为网络基础,以J2EE与J2ME为技术架构,使用成熟的中间件和可复用的业务组件实现了系统的跨平台性、伸缩性、可移植性和可维护性,为"卷烟上水平"提供有力的市场保障。 相似文献
40.
In regularized regression the vectors that lie in Krylov and eigen subspaces, formed in PLS and PC regressions respectively, provide useful low dimensional approximations for the LS regression coefficient vector. By preconditioning the LS normal equations we provide a framework in which to combine these methods, and so exploit both of their respective advantages. The link between the proposed method to orthogonal signal correction and to cyclic subspace regression is made. The performance of the proposed solution in reducing the dimension of the regression problem, and the shrinkage properties of the resulting coefficient vector, are both examined. 相似文献