Shift Invariant Discrete Wavelet Transforms

Olkkonen, H.; Olkkonen, Juuso

doi:10.5772/23828

Cited by 12 publications

(11 citation statements)

References 16 publications

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“…Thus, the frequency components of the signal are shifted with the same values. The filter h(t) has the linear phase property which is in consistence with other investigations [35,36]. The sampling frequency can be obtained by Nyquist's theorem in the ideal case.…”

Section: Complex Transform Based Ofdma Systemsupporting

confidence: 56%

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Development of Signal Recovery Algorithm for Overcoming PAPR in OFDMA Communication System

Emarah

Tokhy

Kasban

2021

Arab Journal of Nuclear Sciences and Applications

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This paper focuses on overcoming the high Peak to Average Power Ratio challenging within Orthogonal Frequency Division Multiplexing Asynchronous (OFDMA) communication system. This signal is modulated using differential phase-shift keying and quadrature amplitude modulation techniques. It is degraded under different noise attacks. Signal recovery algorithms are supposed for overcoming the high peak power problem. This issue is resolved through the detection of maximum peaks within threshold peak values of the power amplifier output signal. Additionally, these peaks are identified depending on the extracted power density and order statistics features. This system is trained using an artificial neural network under different channel impairments. Besides, the error rate of this network is computed in presence of different channel fadings. Rayleigh fading imposes the best performance for the transmitted OFDMA signal. Moreover, recognition of 100% is attained using the high order statistics compared to the power density features in presence of noise attacks.

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Section: Complex Transform Based Ofdma Systemsupporting

confidence: 56%

“…An algorithm for modulation purposes of OFDMA signal using CWT is investigated. This algorithm is proposed for multidimensional signal processing in previous works [5,30,[34][35][36] is presented in Fig. (2).…”

Section: Complex Transform Based Ofdma Systemmentioning

confidence: 99%

Development of Signal Recovery Algorithm for Overcoming PAPR in OFDMA Communication System

Emarah

Tokhy

Kasban

2021

Arab Journal of Nuclear Sciences and Applications

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“…Due to the amplitude reductions of the AF signal produced by apneic events [ 15 ], as well as the ability of the DWT to assign low coefficients to the flatter signal parts and high coefficients to the steeper [ 42 ], it is expected to find higher coefficients in the signal D 8 of the subjects without OSA. Consequently, and according to previous spectral analyses of AF [ 16 , 43 ], higher values of M 1 D 8 , M 2 D 8 , Max D 8 , and Min D 8 , as well as lower values of M 3 D 8 and M 4 D 8 , are expected in these subjects.…”

Section: Methodsmentioning

confidence: 99%

Wavelet Analysis of Overnight Airflow to Detect Obstructive Sleep Apnea in Children

Barroso-García

Gutiérrez‐Tobal

Gozal

et al. 2021

Sensors

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This study focused on the automatic analysis of the airflow signal (AF) to aid in the diagnosis of pediatric obstructive sleep apnea (OSA). Thus, our aims were: (i) to characterize the overnight AF characteristics using discrete wavelet transform (DWT) approach, (ii) to evaluate its diagnostic utility, and (iii) to assess its complementarity with the 3% oxygen desaturation index (ODI3). In order to reach these goals, we analyzed 946 overnight pediatric AF recordings in three stages: (i) DWT-derived feature extraction, (ii) feature selection, and (iii) pattern recognition. AF recordings from OSA patients showed both lower detail coefficients and decreased activity associated with the normal breathing band. Wavelet analysis also revealed that OSA disturbed the frequency and energy distribution of the AF signal, increasing its irregularity. Moreover, the information obtained from the wavelet analysis was complementary to ODI3. In this regard, the combination of both wavelet information and ODI3 achieved high diagnostic accuracy using the common OSA-positive cutoffs: 77.97%, 81.91%, and 90.99% (AdaBoost.M2), and 81.96%, 82.14%, and 90.69% (Bayesian multi-layer perceptron) for 1, 5, and 10 apneic events/hour, respectively. Hence, these findings suggest that DWT properly characterizes OSA-related severity as embedded in nocturnal AF, and could simplify the diagnosis of pediatric OSA.

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“…'de görüldüğü gibi birbirini tümleyen alçak ve yüksek geçiren filtrelerden geçirilerek alçak olarak A ve yüksek olarak D frekanslı bileşenlerine ayrıştırılır. Konu hakkında daha detaylı bilgi [17] kaynaktan elde edilebilir. Şekil 2.…”

Section: Ayrık Dalgacık Dönüşümüunclassified

Kanonik Korelasyon Analiz Tabanlı Ses Ayrıştırma Algoritmalarının İşlem Süresi Azaltımı

Çelik

Ilgin

Sevim

2019

Teknik Bilimler Dergisi

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Bağımsız bileşen analizi, Kanonik korelasyon analizi, Çekidek kanonik korelasyon analizi, Ayrık dalgacık dönüşümü Özet: Gürültülü ortamlarda ses işaretinin gürültüsüz olarak elde edilmesi oldukça önemlidir. Karışım ortamı ve gürültü kaynakları bilinemediğinden dolayı ayrıştırma işlemi oldukça zordur. En az iki sinyalin karışımını içeren bir veri kümesinden bu karışımı oluşturan her bir kaynağın tahmin edilmesi kör kaynak ayrıştırma olarak tanımlanmaktadır. Kör kaynak ayrıştırma yöntemlerinin başarımı, işlem süresi ve doğruluğu ile belirlenmektedir Bu çalışmada doğrusal biçimde karışmış olan farklı ses işaretleri, Kanonik Korelasyon Analiz tabanlı algoritmaları kullanılarak ayrıştırılmıştır. Algoritmaların başarım oranlarıyla birlikte, işlemsel yükleri ile orantılı olan işlem süreleri karşılaştırılmış ve ayrıca algoritmaların işlem sürelerini düşürmek için Ayrık Dalgacık Dönüşümü yönteminden faydalanılmıştır. Bunlara ek olarak farklı veri uzunlukları kullanılarak, veri uzunluğunun algoritma performansları üzerindeki etkisi incelenmiştir.

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Shift Invariant Discrete Wavelet Transforms

Cited by 12 publications

References 16 publications

Development of Signal Recovery Algorithm for Overcoming PAPR in OFDMA Communication System

Development of Signal Recovery Algorithm for Overcoming PAPR in OFDMA Communication System

Wavelet Analysis of Overnight Airflow to Detect Obstructive Sleep Apnea in Children

Kanonik Korelasyon Analiz Tabanlı Ses Ayrıştırma Algoritmalarının İşlem Süresi Azaltımı

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