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关于高斯随机游动之Shepp统计量的极值的一些渐近结果(英文)
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作者 谭中权 《数学进展》 CSCD 北大核心 2015年第1期141-150,共10页
设{x_i∶i≥1}是一列独立的标准化的服从正态分布的随机变量序列,令S_k=∑_(i=1)~kX_i,S_0=0为相关的高斯随机游动.当T是一正的独立于{X_i∶i≥1}的随机变量时,获得了Shepp统计量之极值M_T^(N)=max(k+L-1)-S_(k-1))的尾渐近展开.同时也... 设{x_i∶i≥1}是一列独立的标准化的服从正态分布的随机变量序列,令S_k=∑_(i=1)~kX_i,S_0=0为相关的高斯随机游动.当T是一正的独立于{X_i∶i≥1}的随机变量时,获得了Shepp统计量之极值M_T^(N)=max(k+L-1)-S_(k-1))的尾渐近展开.同时也证明了M_T^(N)的几乎处处极限定理. 展开更多
关键词 极值 Shepp统计量 高斯随机游动 几乎处处极限定理
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Semantic image annotation based on GMM and random walk model 被引量:1
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作者 田东平 《High Technology Letters》 EI CAS 2017年第2期221-228,共8页
Automatic image annotation has been an active topic of research in computer vision and pattern recognition for decades.A two stage automatic image annotation method based on Gaussian mixture model(GMM) and random walk... Automatic image annotation has been an active topic of research in computer vision and pattern recognition for decades.A two stage automatic image annotation method based on Gaussian mixture model(GMM) and random walk model(abbreviated as GMM-RW) is presented.To start with,GMM fitted by the rival penalized expectation maximization(RPEM) algorithm is employed to estimate the posterior probabilities of each annotation keyword.Subsequently,a random walk process over the constructed label similarity graph is implemented to further mine the potential correlations of the candidate annotations so as to capture the refining results,which plays a crucial role in semantic based image retrieval.The contributions exhibited in this work are multifold.First,GMM is exploited to capture the initial semantic annotations,especially the RPEM algorithm is utilized to train the model that can determine the number of components in GMM automatically.Second,a label similarity graph is constructed by a weighted linear combination of label similarity and visual similarity of images associated with the corresponding labels,which is able to avoid the phenomena of polysemy and synonym efficiently during the image annotation process.Third,the random walk is implemented over the constructed label graph to further refine the candidate set of annotations generated by GMM.Conducted experiments on the standard Corel5 k demonstrate that GMM-RW is significantly more effective than several state-of-the-arts regarding their effectiveness and efficiency in the task of automatic image annotation. 展开更多
关键词 semantic image annotation Gaussian mixture model GMM) random walk rival penalized expectation maximization (RPEM) image retrieval
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