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战略防御仿真器性能评估
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作者 孙俊堂 c.smith +4 位作者 J.Farschon A.Harvey J.Hill R.Nisley R.Plock 《战略防御》 1990年第1期61-68,共8页
SD-PA是一个对集成模式的多层防御系统的各个阶段的闭环SDI 系统的有效性仿真。它是可变且有效的。因此它允许分析者对结构概念中的各部分进行折衷考虑并对大量的参数进行灵敏性研究。SDS-PA程序用主动搜索的方法确定SDI各部分之间的相... SD-PA是一个对集成模式的多层防御系统的各个阶段的闭环SDI 系统的有效性仿真。它是可变且有效的。因此它允许分析者对结构概念中的各部分进行折衷考虑并对大量的参数进行灵敏性研究。SDS-PA程序用主动搜索的方法确定SDI各部分之间的相互影响,这些部分指特定的战略威胁包括没有用任何人为的方法将作战过程分为助推段、后助推段、中段以及末段的防御抑制。SDI的每一部分(传感器和武器)都独立建模,使用者将威胁部分集中到一个特定数目的目标群,称为威胁管道,每个管道可以包括使用者指定的一定数目的导弹,这些导弹的状态每隔一定的时间进行采样,采样间隔或由使用者确定或由理想的分辨能力决定。使用胁胁管道保留了基本的几何关系和时间基准的灵敏性,而且不必对每个目标的弹道进行仿真。在要求分辨率很高的范围内,可以将每个威胁管道的目标群集中到一个助推器来运载。 展开更多
关键词 仿真器 防御 SDI系统
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核心育种单位在家畜遗传改良中的应用
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作者 c.smith 齐广海 《国外畜牧学(草食家畜)》 1989年第1期13-16,共4页
本文就发展中国家如何设计遗传改良体系谈了一些意见。当然,这种体系依畜种、国家、生产条件和市场需求的不同而不同。由于作者没有在发展中国家从事育种工作的实践经验,所以只能根据发达国家的经验和文献对此进行探讨。
关键词 家畜育种 遗传 核心育种单位
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Damage mechanism identification in composites via machine learning and acoustic emission 被引量:4
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作者 C.Muir B.Swaminathan +6 位作者 A.S.Almansour K.Sevener c.smith M.Presby J.D.Kiser T.M.Pollock S.Daly 《npj Computational Materials》 SCIE EI CSCD 2021年第1期852-866,共15页
Damage mechanism identification has scientific and practical ramifications for the structural health monitoring,design,and application of composite systems.Recent advances in machine learning uncover pathways to ident... Damage mechanism identification has scientific and practical ramifications for the structural health monitoring,design,and application of composite systems.Recent advances in machine learning uncover pathways to identify the waveform-damage mechanism relationship in higher-dimensional spaces for a comprehensive understanding of damage evolution.This review evaluates the state of the field,beginning with a physics-based understanding of acoustic emission waveform feature extraction,followed by a detailed overview of waveform clustering,labeling,and error analysis strategies.Fundamental requirements for damage mechanism identification in any machine learning framework,including those currently in use,under development,and yet to be explored,are discussed. 展开更多
关键词 COMPOSITES COMPOSITE MECHANISM
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A machine learning framework for damage mechanism identification from acoustic emissions in unidirectional SiC/SiC composites 被引量:2
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作者 C.Muir B.Swaminathan +7 位作者 K.Fields A.S.Almansour K.Sevener c.smith M.Presby J.D.Kiser T.M.Pollock S.Daly 《npj Computational Materials》 SCIE EI CSCD 2021年第1期1326-1335,共10页
In this work,we demonstrate that damage mechanism identification from acoustic emission(AE)signals generated in minicomposites with elastically similar constituents is possible.AE waveforms were generated by SiC/SiC c... In this work,we demonstrate that damage mechanism identification from acoustic emission(AE)signals generated in minicomposites with elastically similar constituents is possible.AE waveforms were generated by SiC/SiC ceramic matrix minicomposites(CMCs)loaded under uniaxial tension and recorded by four sensors(two models with each model placed at two ends).Signals were encoded with a modified partial power scheme and subsequently partitioned through spectral clustering.Matrix cracking and fiber failure were identified based on the frequency information contained in the AE event they produced,despite the similar constituent elastic properties of the matrix and fiber.Importantly,the resultant identification of AE events closely followed CMC damage chronology,wherein early matrix cracking is later followed by fiber breaks,even though the approach is fully domain-knowledge agnostic.Additionally,the partitions were highly precise across both the model and location of the sensors,and the partitioning was repeatable.The presented approach is promising for CMCs and other composite systems with elastically similar constituents. 展开更多
关键词 COMPOSITES DAMAGE MECHANISM
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