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A continuous differentiable wavelet threshold function for speech enhancement 被引量:3
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作者 贾海蓉 张雪英 白静 《Journal of Central South University》 SCIE EI CAS 2013年第8期2219-2225,共7页
Enhanced speech based on the traditional wavelet threshold function had auditory oscillation distortion and the low signal-to-noise ratio (SNR). In order to solve these problems, a new continuous differentiable thresh... Enhanced speech based on the traditional wavelet threshold function had auditory oscillation distortion and the low signal-to-noise ratio (SNR). In order to solve these problems, a new continuous differentiable threshold function for speech enhancement was presented. Firstly, the function adopted narrow threshold areas, preserved the smaller signal speech, and improved the speech quality; secondly, based on the properties of the continuous differentiable and non-fixed deviation, each area function was attained gradually by using the method of mathematical derivation. It ensured that enhanced speech was continuous and smooth; it removed the auditory oscillation distortion; finally, combined with the Bark wavelet packets, it further improved human auditory perception. Experimental results show that the segmental SNR and PESQ (perceptual evaluation of speech quality) of the enhanced speech using this method increase effectively, compared with the existing speech enhancement algorithms based on wavelet threshold. 展开更多
关键词 continuous differentiable wavelet threshold fimction speech enhancement Bark wavelet packet non-fixed deviation noise
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THE CONTINUAL DIFFERENTIABLE PEAK-UNIMODAL SOLUTIONS OF FEIGENBAUM’S FUNCTIONAL EQUATIONS
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作者 程宝龙 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1989年第5期419-426,共8页
For the famous Feigenbaum's equations, in this paper, we established its constructive theorem of the peak-unimodal, then we found out other paths to explore the peak-unimodal solutions. For example, we proceed on ... For the famous Feigenbaum's equations, in this paper, we established its constructive theorem of the peak-unimodal, then we found out other paths to explore the peak-unimodal solutions. For example, we proceed on the direction to try the non-symmetrical continuous peak-unimodal solutions and C1 solutions. 展开更多
关键词 THE CONTINUAL differentiable PEAK-UNIMODAL SOLUTIONS OF FEIGENBAUM S FUNCTIONAL EQUATIONS
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EXPECTED DISCOUNTED PENALTY FUNCTION AT RUIN FOR RISK PROCESS PERTURBED BY DIFFUSION UNDER INTEREST FORCE 被引量:1
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作者 Zhao Xia Ouyang Zisheng 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2005年第3期289-296,共8页
In this article, the risk process perturbed by diffusion under interest force is considered, the continuity and twice continuous differentiability for Фδ(u,w) are discussed,the Feller expression and the integro-di... In this article, the risk process perturbed by diffusion under interest force is considered, the continuity and twice continuous differentiability for Фδ(u,w) are discussed,the Feller expression and the integro-differential equation satisfied by Фδ (u ,w) are derived. Finally, the decomposition of Фδ(u,w) is discussed, and some properties of each decomposed part of Фδ(u,w) are obtained. The results can be reduced to some ones in Gerber and Landry's,Tsai and Willmot's, and Wang's works by letting parameter δ and (or) a be zero. 展开更多
关键词 risk process perturbed by diffusion under interest force expected discounted penalty at ruin twice continuous differentiability integro-differential equation.
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A Basic Method of Constructing Production Functions
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作者 Guo Yaohuang Wang Yaping Zhang Wel(School of Economics and Management,Soultwest Jiaotong University), Chengdu 610031,China 《Journal of Modern Transportation》 1995年第2期127-132,共6页
In this paper,a new basic method of constructing smooth production functions isgiven,and many ordinary production functions are drawn. It is obvious thatsome more production functions can be obtained from the method.
关键词 production function continuously differentiable function homogeneousfunction
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A Numerical Method for Solving Ill-Conditioned Equation Systems Arising from Radial Basis Functions
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作者 Edward J. Kansa 《American Journal of Computational Mathematics》 2023年第2期356-370,共15页
Continuously differentiable radial basis functions (C<sup>∞</sup>-RBFs), while being theoretically exponentially convergent are considered impractical computationally because the coefficient matrices are ... Continuously differentiable radial basis functions (C<sup>∞</sup>-RBFs), while being theoretically exponentially convergent are considered impractical computationally because the coefficient matrices are full and can become very ill- conditioned. Similarly, the Hilbert and Vandermonde have full matrices and become ill-conditioned. The difference between a coefficient matrix generated by C<sup>∞</sup>-RBFs for partial differential or integral equations and Hilbert and Vandermonde systems is that C<sup>∞</sup>-RBFs are very sensitive to small changes in the adjustable parameters. These parameters affect the condition number and solution accuracy. The error terrain has many local and global maxima and minima. To find stable and accurate numerical solutions for full linear equation systems, this study proposes a hybrid combination of block Gaussian elimination (BGE) combined with arbitrary precision arithmetic (APA) to minimize the accumulation of rounding errors. In the future, this algorithm can execute faster using preconditioners and implemented on massively parallel computers. 展开更多
关键词 continuously differentiable Radial Basis Functions Global Maxima and Minima Solutions of Ill-Conditioned Linear Equations Block Gaussian Elimination Arbitrary Precision Arithmetic
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CONTINUITY IN FUNCTIONAL DIFFERENTIAL EQUATIONS WITH INFINITE DELAY
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作者 T.A.BURTON 冯祐和 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 1991年第3期229-244,共16页
In this paper, we investigate the continuous dependence of solutions of the functional dif-ferential equation with infinite delay x'(t) = f(t, x_t) on initial functions. Endowing the phasespare a g-norm as well as... In this paper, we investigate the continuous dependence of solutions of the functional dif-ferential equation with infinite delay x'(t) = f(t, x_t) on initial functions. Endowing the phasespare a g-norm as well as a supremum norm. we show that if the equation satifies a mild fadingmemory dondition, then the continuity of f in respect to the topology induced by the supremumnorm can yield the continuity of solutions of the equation in respect to the topology induced bythe g-norm which is stronger than the ahead one. 展开更多
关键词 CONTINUITY IN FUNCTIONAL DIFFERENTIAL EQUATIONS WITH INFINITE DELAY
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Density functions of doubly-perturbed stochastic differential equations with jumps
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作者 Yulin SONG 《Frontiers of Mathematics in China》 SCIE CSCD 2018年第1期161-172,共12页
We consider a real-valued doubly-perturbed stochastic differential equation driven by a subordinated Brownian motion. By using classic Malliavin calculus, we prove that the law of the solution is absolutely continuous... We consider a real-valued doubly-perturbed stochastic differential equation driven by a subordinated Brownian motion. By using classic Malliavin calculus, we prove that the law of the solution is absolutely continuous with respect to the Lebesgue measure on R. 展开更多
关键词 Doubly-perturbed stochastic differential equations (SDEs) absolute continuity Malliavin calculus subordinated Brownian motions
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