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Spectrum prediction estimates channel future status from history statistics, which greatly improved the efficiency of spectrum sensing in cognitive radio networks. Current researches mainly focus on improving speed and accuracy of prediction. Few researches discuss the energy-efficient design of spectrum prediction. Since energy-efficient affect working hours and transmission efficiency, that is an...
Because of the black-out phenomenon and limited available navigation means in reentry phase for lifting reentry vehicles, the strapdown inertial navigation system (SINS) based on geocentric inertial coordinate system is employed and analyzed. Various Error sources of SINS are modeled to analyze the influence on navigation accuracy by means of covariance analysis. Then the importance degree of each...
A specific issue in the voice password system is addressed in this paper: When the text content of target speaker's enrollment password has been already known by imposters, they can do a well-behaved impersonation using the same text content as the target speaker. This results in a much higher false acceptance than the traditional voice password system. N-gram based nearest neighbor algorithm is proposed...
The problem of semi-supervised dimensionality reduction with kernels called KS2DR is considered for semi-supervised learning. In this setting, domain knowledge in the form of pair constraints is adopted to specify whether pairs of instances belong to the same class or not. KS2DR can project the samples data onto a set of `useful' features and preserve the structure of unlabeled samples data as well...
Non-negative matrix factorization (NMF) is an unsupervised method whose aim is to find an approximate factorization V ?? WH, which decomposes V = [vij] ?? Rn*m into non-negative matrices W = [wij] ?? Rn*r and H = [hij] ?? Rr*m with wij, hij ?? 0. In this paper, we present an extension to the non-negative matrix factorization called DMNMF and adopt the learned distance metric to measure the between-class...
The grading of woods is mainly determined by the defects on wood surfaces and determines the potential uses and values for the sawmills. However, the dimensions of wood images are high, which is difficult to deal with. Dimensionality reduction is one of key interests in processing the higher-dimensional image data without losing intrinsic information. The problem of sub-pattern based discriminative...
The values of a board have a direct relationship with the grading determined by the number and distribution of defects. Currently, wood defects recognition research are one of the key interests in the wood industry. In this paper, DWT and NMF are employed and we apply the decomposition to wood feature selection. The feature images by DWT can describe the characteristics and differences of the defects...
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