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1
Content available Amended Adaptive Algorithm for Corpus Based Improved Speech Enhancement
Priya P. Shanmuga, Nidhyananthan S. Selva, Kumari R. Shantha Selva
International Journal of Electronics and Telecommunications
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2019
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Vol. 65, No. 3
513--517
EN
Speech enhancement objective is to improve the noisy speech signals for human perception. The intention of speech enhancement algorithm is to improve the performance of the communication, when the signal is occluded by noise. The quality and intelligibility of speech is reduced because of the presence of background noise. There are various adaptive filtering algorithms for speech enhancement. The existing least mean square and normalised least mean square algorithms have the problem of choosing the step size that guarantees the stability of the algorithm. To overcome this problem, we focus on speech enhancement by amended adaptive filtering. The proposed algorithm follows blind source separation strategy using adaptive filtering. Comparison of existing adaptive filtering algorithms with proposed algorithm justifies the amendment incorporated in this paper. Taking the objective criteria into account the algorithms has been tested for segmental signal to noise ratio (SegSNR), segmental mean square error (SegMSE), signal to noise ratio and mean square error. The proposed algorithm can be used for hand-free cell phone, hearing aids and teleconferencing systems.
2
Content available remote Identification of Weibull Distribution Parameters in the Presence of Noise
Gontarz S., Gumiński R.
Machine Dynamics Research
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2016
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Vol. 40, No. 3
41--52
EN
Wear and tear processes, in combination with the dynamics of machines, are the source of many methods of technical objects diagnosis which are useful in practice. Unfortunately, generation of signals is inherently associated with generation of noise and disturbances, which makes the tasks of defining the symptoms and extraction of diagnostic information much more difficult. The article presents a proposal of implementation of a solution eliminating the noise while using the blind equalization method, while also presenting the influence that use of this method has influence on selected reliability characteristics.
3
Content available Sequential separation of twin pregnancy electrocardiograms
Kotas M., Leski J. M., Wrobel J.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2016
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Vol. 64, nr 1
91--101
EN
We propose to tackle the problem of maternal abdominal electric signals decomposition with a combined application of independent component analysis and projective or adaptive filtering. The developed method is employed to process the four-channel abdominal signals recorded during twin pregnancy. These signals are complicated mixtures of the maternal ECG, the ECGs of the fetal twins and noise of various origin. Although the independent component analysis cannot separate the respective signals, the proposed combination of the methods deals with this task successfully. A simulation experiment confirms high efficiency of this approach.
4
Content available Regularized nonnegative matrix factorization: Geometrical interpretation and application to spectral unmixing
Zdunek R.
International Journal of Applied Mathematics and Computer Science
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2014
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Vol. 24, no. 2
233--247
EN
Nonnegative Matrix Factorization (NMF) is an important tool in data spectral analysis. However, when a mixing matrix or sources are not sufficiently sparse, NMF of an observation matrix is not unique. Many numerical optimization algorithms, which assure fast convergence for specific problems, may easily get stuck into unfavorable local minima of an objective function, resulting in very low performance. In this paper, we discuss the Tikhonov regularized version of the Fast Combinatorial NonNegative Least Squares (FC-NNLS) algorithm (proposed by Benthem and Keenan in 2004), where the regularization parameter starts from a large value and decreases gradually with iterations. A geometrical analysis and justification of this approach are presented. The numerical experiments, carried out for various benchmarks of spectral signals, demonstrate that this kind of regularization, when applied to the FC-NNLS algorithm, is essential to obtain good performance.
5
Content available remote Blind separation of delayed sources based on second-order Taylor approximation
Li H., Shen Y., Wang J.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 1b
253--256
EN
Conventional linear instantaneous mixing model becomes unsuitable if propagation time delays are taken into account. A blind separation algorithm based on second-order Taylor approximation for delayed sources (SOTADS) is presented, under the constraint that time delays are small in comparison with the coherence time of each source. Simulation results validate that the proposed algorithm performs superior than related approaches even when the constraint is violated.
PL
Zaprezentowano algorytm ślepej separacji bazujący na aproksymacji Taylora drugiego rzędu dla źródeł z opóźnieniem SOTADS. Założono że czas opóźnienia jest mały w porównaniu z czasem koherencji obu źródeł.
6
Content available remote Adaptive Improved RLS Algorithm for Blind Source Separation
Ou S., Wang X., Gao Y.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 3b
81--83
EN
Based on an adaptive combination of two RLS-type algorithms with different forgetting factor, an effective scheme is proposed to improve the performance of the RLS-type algorithm for blind source separation. A mixing parameter for adjusting the proportion of the two RLS algorithms is introduced in an attempt to put together the best properties of them, and its adaptive rule is obtained by means of a natural gradient criterion. Experimental results demonstrate the good performance of the proposed approach in different kinds of environments.
PL
W artykule przedstawiono nową, efektywniejszą strukturę algorytmu RLS do ślepej separacji sygnałów, bazującą na adaptacyjnej kombinacji dwóch takich algorytmów z różnymi współczynnikami ważenia. W celu uzyskania jak najlepszego wykorzystania ich własności, zastosowano parametr, który pozwala na ich dostrojenie. Wyniki eksperymentalne potwierdzają skuteczność działania.
7
Content available remote Online Blind Separation of Dependent Sources Using Nonnegative Matrix Factorization Based on KL Divergence
Li H., Shen Y., Wang J.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 1b
278-281
EN
This paper proposes a novel online algorithm for nonnegative matrix factorization (NMF) based on the generalized Kullback-Leibler (KL) divergence criterion, aimed to overcome the high computation problem of large-scale data brought about by conventional batch NMF algorithms. It features stable updating the factors alternately for each new-coming observation, and provides an efficient solution for the blind separation of statistically dependent sources (i.e., the sources are mutually correlated). Our theoretic analysis is validated by simulation examples.
PL
Przedstawiono nowy algorytm do faktoryzacji nieujemnej macierzy bazujący na kryterium Kullback-Leibler, pozwalający usprawnić problem obliczeń dużej ilości danych. Algorytm sukcesywnie zmienia współczynniki i pozwala na ślepą separację statystycznie zależnych źródeł.
8
Content available remote Noise Detection for Latent Component Classification in Ensemble Method
Szupiluk R.
Przegląd Elektrotechniczny
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2010
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R. 86, nr 1
144-146
EN
We present a novel concept of the random noise detection applied in model integration process. The ensemble method is based on decomposition of the multivariate variable containing model results. The decomposition originating from Blind Signal Separation gives us the latent components with destructive or constructive impact on the prediction quality. The identification and elimination of the noisy signals should improve final prediction result. The validity of our concept is presented on the real problem of load forecasting in the Polish Power System.
PL
W artykule przedstawiono nową metodę detekcji szumów losowych zastosowana w procesie agregacji modeli. W rozwijanej metodzie agregacji zbieramy rezultaty poszczególnych modeli predykcyjnych w jednej wielowymiarowej zmiennej. Zakładamy, że zawiera ona konstruktywne oraz destrukcyjne dla wyników prognozy ukryte komponenty. Komponenty te możemy estymować metodami ślepej separacji sygnałów. Poprawna identyfikacji oraz eliminacja komponentów szumowych prowadzi do poprawy ostatecznych wyników predykcji. Potwierdzeniem skuteczności proponowanych rozwiązań jest przykład predykcji obciążenia systemu elektroenergetycznego.
9
Content available An Improved Method of Permutation Correction in Convolutive Blind Source Separation
Wang L., Ding H., Yin F.
Archives of Acoustics
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2010
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Vol. 35, No. 4
493-504
EN
This paper proposes an improved method of solving the permutation problem inherent in frequency-domain of convolutive blind source separation (BSS). It combines a novel inter-frequency dependence measure: the power ratio of separated signals, and a simple but effective bin-wise permutation alignment scheme. The proposed method is easy to implement and surpasses the conventional ones. Simulations have shown that it can provide an almost ideal solution of the permutation problem for a case where two or three sources were mixed in a room with a reverberation time of 130 ms.
10
Content available remote Ensemble neural network approach for accurate load forecasting in a power system
Siwek K., Osowski S., Szupiluk R.
International Journal of Applied Mathematics and Computer Science
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2009
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Vol. 19, no 2
303-315
EN
The paper presents an improved method for 1-24 hours load forecasting in the power system, integrating and combining different neural forecasting results by an ensemble system. We will integrate the results of partial predictions made by three solutions, out of which one relies on a multilayer perceptron and two others on self-organizing networks of the competitive type. As the expert system we will apply different integration methods: simple averaging, SVD based weighted averaging, principal component analysis and blind source separation. The results of numerical experiments, concerning forecasting the hourly load for the next 24 hours of the Polish power system, will be presented and discussed. We will compare the performance of different ensemble methods on the basis of the mean absolute percentage error, mean squared error and maximum percentage error. They show a significant improvement of the proposed ensemble method in comparison to the individual results of prediction. The comparison of our work with the results of other papers for the same data proves the superiority of our approach.
11
Content available remote Logatom articulation index evaluation of speech enhanced by blind source separation and single-channel noise reduction
Drgas Sz., Kociński J., Sęk A. P.
Archives of Acoustics
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2008
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Vol. 33, No. 4
455-474
EN
The subjective logatom articulation index of speech signals enhanced by means of various digital signal processing methods has been measured. To improve intelligibility, the convolutive blind source separation (BSS) algorithm by Parra and Spence [1] has been used in combination with classical denoising algorithms. The efficiency of these algorithms has been investigated for speech material recorded in two spatial configurations. It has been shown that the BSS algorithm can highly improve speech recognition. Moreover, a combination of the BSS with single-microphone denoising methods can additionally increase the logatom articulation index.
12
Content available CDMA wireless system with blind multiuser detector
Leong W. Y., Homer J.
Journal of Telecommunications and Information Technology
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2006
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nr 1
69-75
EN
In this paper we present an approach capable of countering the presence of multiple access interference (MAI) in code division multiple access (CDMA) channels. We develop and implement a blind multiuser detector, based on an independent component analysis (ICA) to mitigate both MAI and noise. This algorithm has been utilized in blind source separation (BSS) of unknown sources from their linear mixtures. It can also be used for estimation of the basis vectors of BSS. The aim is to include an ICA algorithm within a wireless receiver in order to reduce the level of interference in CDMA systems. This blind multiuser detector requires less precise knowledge of the channel than does the conventional single-user receiver. The proposed blind multiuser detector is made robust with respect to imprecise knowledge of the received signature waveforms of the user of interest. Several experiments are performed in order to verify the validity of the proposed learning algorithm.
13
Content available remote Comparisons of prewhitening algorithms of noisy signals
Cichocki A., Osowski S., Siwek K.
Przegląd Elektrotechniczny
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2005
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R. 81, nr 2
22-25
EN
The paper presents and compares the performance of different prewhitening algorithms of the signals in the presence of white noise. The algorithms have been applied to the decorrelation of the statistically dependent and independent signals mixed together. The presented technigue may find application in the solutions of the blind source separation problems.
PL
Artykuł przedstawia i porównuje działanie różnych algorytmów wybielania sygnałów w obecności białego szumu. Badane algorytmy zastosowano do dekorelacji zależnych i niezależnych sygnałów zmieszanych w nieznany sposób. Proponowane rozwiązanie znajduje zastosowanie jako wstępny etap ślepej separacji sygnałów.
14
Content available remote Reconstruction of digital images from their instantaneous mixtures by the blind source separation algorithms
Adhami R., Janik T.
Image Processing & Communications
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2005
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Vol. 10, no 1
35-42
EN
The goal of the blind source separation (BSS) is to recover independent sources from the sensor observation which are unknown linear mixtures of the unobserved source signals. In contrast to correlation-based transformation such as the principal component analysis, the blind techniques not only decorrelate the signals (second-order statistics) but also reduce higher-order dependencies, attempting to make the signals as independent as possible. In this paper we introduce the BSS algorithms with the emphasis on applications in image processing. Computer simulations illustrate and confirm the usefulness and performance of the discussed algorithms.
15
Content available O metodach ślepego przetwarzania sygnałów diagnostycznych
Dybała J.
Diagnostyka
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2005
|
Vol. 36
53--60
PL
W artykule przedstawiono metody ślepego przetwarzania sygnałów traktując je jako interesujące sposoby wyodrębniania sygnałów informacyjnych i eliminacji zakłóceń. Zaprezentowano różne modele propagacji i mieszania sygnałów oraz różne metody rekonstrukcji tych sygnałów przy pomocy odpowiednich sieci neuronowych. W końcowej części artykułu omówiono problemy związane z zastosowaniem tych metod w diagnostyce technicznej i przedstawiono pewne modyfikacje i rozszerzenia klasycznego ślepego przetwarzania sygnałów dostosowujące przedstawione podejście do specyfiki diagnozowania obiektów technicznych.
EN
The article presents methods of blind signal processing, which make possible the separation the informative signals and the elimination of disturbances. Different models of propagation and mixing of signals are presented and different methods of reconstruction of source signals with use of neural networks are showed. In last section of article, problems related with application of mentioned methods in technical diagnostics are discussed. Also some modifications and extensions of classical blind signal processing are showed, adapting presented approach to peculiarity of diagnosing of technical objects.
16
Extraction of fetal fMCG
Czyżewska M., Bachir W., Dunajski Z.
Elektronika : konstrukcje, technologie, zastosowania
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2004
|
Vol. 45, nr 8-9
140-142
EN
Reliable extraction of fetal MCG from raw signals, measured by SQUID magnetometer, is of high importance for clinical applications of fetal magnetocardiography. For extraction of the fetal magnetocardiogram, two statistical signal processing methods are developed. SVD (Singluar Value Decomposition) and BSS algorithm (JADE joint approximate diagonalization of eigenmatrices) based methods were utilized for the extraction of fMCG. The former exhibits sufficient effectiveness for fetal MCG extraction from single channel recordings. The latter, however, shows adequate reliability for fMCG separation provided that at least three source channels are available.
PL
Rzetelne wydzielenie sygnału serca płodu z sygnału mierzonego za pomocą magnetometru z czujnikiem SQUID ma wysokie znaczenie dla zastosowań klinicznych magnetokardiografi serca płodu. W celu wydzielenia sygnału magnetokardiograficznego serca płodu przedstawione zostały dwie metody statystyczne. Wykorzystano rozkład macierzy na wartości szczególne - SVD oraz algorytm bazujący na wydzielaniu sygnału "na ślepo" (BSS) JADE. Pierwszy algorytm wykazuje zadowalającą efektywność przy wydzielaniu sygnału fMKG rejestrowanego za pomocą jednego kanału. Drugi z algorytmów, mimo że wykazuje odpowiednią wiarygodność sygnału fMCG wymaga co najmniej trzech źródeł sygnału.
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