Presentation 2001/12/14
Blind Separation Using Adaptive Nonlinear Functions Controlled by Kurtosis
Takayuki Sakai, Kenji Nakayama, Akihiro Hirano,
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Abstract(in English) Convergence and separation performances are highly dependent on a relation between probability density functions(pdf)of signal sources and nonlinear functions used in updating coefficients of a separation block. This relation was analyzed based on kurtosis κ_4. It was suggested that than y and y^3, where y is the output, are useful nonlinear functions for super-Gaussian(κ_4>0)and sub-Gaussian(κ_4<0), respectively. In this paper, an adaptive nonlinear function is proposed. It has a form of f(y)=a tanh y+(1-a)y^3/4, where a is controlled by kurtosis. It is assumed that the pdf p(y)of the output signal y satisfies the stability condition f(y)=(dp(y)/dy)/p(y). Based on this assumption, the parameter a and the kurtosis is related. First, the kurtosis is calculated for given a, which takes value in 0≤a≤1. Next, this numerical relation is approximated by a function a=q(κ_4). In a learning process, κ_4(n)of the output signals is calculated at each sample n, and a is determined by a(n)=q(κ_4(n)). Then, the nonlinear function f(y) is adjusted. Blind separation of music signals of 2~5 channels were simulated. The proposed method is superior to a method, which switches tanh y and y^3 based on polarity of κ_4(n).
Keyword(in Japanese) (See Japanese page)
Keyword(in English) Blind separation / Nonlinear functions / Kurtosis / Stabilization / Learning
Paper # NC2001-79
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Committee NC
Conference Date 2001/12/14(1days)
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Registration To Neurocomputing (NC)
Language ENG
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) Blind Separation Using Adaptive Nonlinear Functions Controlled by Kurtosis
Sub Title (in English)
Keyword(1) Blind separation
Keyword(2) Nonlinear functions
Keyword(3) Kurtosis
Keyword(4) Stabilization
Keyword(5) Learning
1st Author's Name Takayuki Sakai
1st Author's Affiliation Division of Electronics and Computer Science, Graduate School of Natural Science and Technology Dept.of Information and Systems Eng.Faculty of Eng.Kanazawa University()
2nd Author's Name Kenji Nakayama
2nd Author's Affiliation Dept.of Information and Systems Eng.Faculty of Eng.Kanazawa University
3rd Author's Name Akihiro Hirano
3rd Author's Affiliation Dept.of Information and Systems Eng.Faculty of Eng.Kanazawa University
Date 2001/12/14
Paper # NC2001-79
Volume (vol) vol.101
Number (no) 534
Page pp.pp.-
#Pages 8
Date of Issue