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面向燃机多工况宽频域工作模态参数识别的随机子空间方法 被引量:2
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作者 左彦飞 庞陈意 +1 位作者 江志农 冯坤 《振动与冲击》 EI CSCD 北大核心 2023年第7期225-236,311,共13页
面向燃气轮机工作状态下多工况、宽频域模态参数识别需求,在对典型燃机整机振动模态分析的基础上,虑及测试数据类型、测点位置与方向的选取及不同运行工况影响,提出一种针对燃机整机工作模态参数识别的随机子空间方法。基于实测振动数据... 面向燃气轮机工作状态下多工况、宽频域模态参数识别需求,在对典型燃机整机振动模态分析的基础上,虑及测试数据类型、测点位置与方向的选取及不同运行工况影响,提出一种针对燃机整机工作模态参数识别的随机子空间方法。基于实测振动数据,对典型燃机工作模态参数进行了自动划分识别。结果表明:通过分别控制行块数,充分挖掘位移、速度、加速度三种类型数据包含的不同频段模态参数信息并对识别结果择优合并,能够较好识别出数十倍于燃机工频的宽频域模态;合理选取测点位置和方向,能够得到关心频段内局部或整体模态;利用多转速运行工况数据,能够区分出受转速影响的整体模态。实现了对燃机整机振动宽频域范围内整体和局部模态、机匣和转子模态的识别,可为在此基础上的动力特性分析、整机动力学模型修正、结构振动状态评估、振动故障特征提取等提供支撑。 展开更多
关键词 燃气轮机 模态参数识别 随机子空间识别方法 宽频域 多工况
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Human action recognition based on chaotic invariants 被引量:1
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作者 夏利民 黄金霞 谭论正 《Journal of Central South University》 SCIE EI CAS 2013年第11期3171-3179,共9页
A new human action recognition approach was presented based on chaotic invariants and relevance vector machines(RVM).The trajectories of reference joints estimated by skeleton graph matching were adopted for represent... A new human action recognition approach was presented based on chaotic invariants and relevance vector machines(RVM).The trajectories of reference joints estimated by skeleton graph matching were adopted for representing the nonlinear dynamical system of human action.The C-C method was used for estimating delay time and embedding dimension of a phase space which was reconstructed by each trajectory.Then,some chaotic invariants representing action can be captured in the reconstructed phase space.Finally,RVM was used to recognize action.Experiments were performed on the KTH,Weizmann and Ballet human action datasets to test and evaluate the proposed method.The experiment results show that the average recognition accuracy is over91.2%,which validates its effectiveness. 展开更多
关键词 chaotic system action recognition chaotic invariants dynamic time wrapping (DTW) relevance vector machines(RVM)
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A variation pixels identification method based on kernel spatial attraction model and local entropy for robust endmember extraction
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作者 赵春晖 田明华 +1 位作者 齐滨 王玉磊 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第8期1990-2000,共11页
A variation pixels identification method was proposed aiming at depressing the effect of variation pixels, which dilates the theoretical hyperspectral data simplex and misguides volume evaluation of the simplex. With ... A variation pixels identification method was proposed aiming at depressing the effect of variation pixels, which dilates the theoretical hyperspectral data simplex and misguides volume evaluation of the simplex. With integration of both spatial and spectral information, this method quantitatively defines a variation index for every pixel. The variation index is proportional to pixels local entropy but inversely proportional to pixels kernel spatial attraction. The number of pixels removed was modulated by an artificial threshold factor α. Two real hyperspectral data sets were employed to examine the endmember extraction results. The reconstruction errors of preprocessing data as opposed to the result of original data were compared. The experimental results show that the number of distinct endmembers extracted has increased and the reconstruction error is greatly reduced. 100% is an optional value for the threshold factor α when dealing with no prior knowledge hyperspectral data. 展开更多
关键词 variation pixels hyperspectral SIMPLEX variation index local entropy kernel spatial attraction
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