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Wavelet analysis

Kun Qian, Christoph Janott, Vedhas Pandit, Zixing Zhang, Clemens Heiser, Winfried Hohenhorst, Michael Herzog, Werner Hemmert, Bjoern Schuller
OBJECTIVE: Obstructive Sleep Apnea (OSA) is a serious chronic disease and a risk factor for cardiovascular diseases. Snoring is a typical symptom of OSA patients. Knowledge of the origin of obstruction and vibration within the upper airways is essential for a targeted surgical approach. Aim of this paper is to systematically compare different acoustic features, and classifiers for their performance in the classification of the excitation location of snore sounds. METHODS: Snore sounds from 40 male patients have been recorded during Drug-Induced Sleep Endoscopy, and categorized by ENT experts...
October 21, 2016: IEEE Transactions on Bio-medical Engineering
Hongqiang Li, Danyang Yuan, Youxi Wang, Dianyin Cui, Lu Cao
Automatic recognition of arrhythmias is particularly important in the diagnosis of heart diseases. This study presents an electrocardiogram (ECG) recognition system based on multi-domain feature extraction to classify ECG beats. An improved wavelet threshold method for ECG signal pre-processing is applied to remove noise interference. A novel multi-domain feature extraction method is proposed; this method employs kernel-independent component analysis in nonlinear feature extraction and uses discrete wavelet transform to extract frequency domain features...
October 20, 2016: Sensors
Siyuan Lu, Xin Qiu, Jianpin Shi, Na Li, Zhi-Hai Lu, Peng Chen, Meng-Meng Yang, Fang-Yuan Liu, Wen-Juan Jia, Yudong Zhang
(Aim) It is beneficial to classify brain images as healthy or pathological automatically, because 3D brain images can generate so much information that it is time consuming and tedious for manual analysis. Among various 3D brain imaging techniques, magnetic resonance (MR) imaging is the most suitable for brain, and it is now widely applied in hospitals, because it is helpful in the four ways of diagnosis, prognosis, pre-surgical, and postsurgical procedures. Although there are automatic detection methods, they suffer from low accuracy...
October 19, 2016: CNS & Neurological Disorders Drug Targets
Shaofeng Wang, Xu Ma, Guoqing Zhang, Yongfeng Jia, Keisuke Hatada
Hydrous ferric arsenate (HFA) is an important arsenic-bearing precipitate in the mining-impacted environment and hydrometallurgical tailings. However, there is no agreement on its local atomic structure. The local structure of HFA was re-probed by employing a full-potential multiple scattering (FPMS) analysis, density functional theory (DFT) calculations, and vibrational spectroscopy. The FPMS simulations indicated that the coordination number of the As-Fe and/or Fe-As in HFA was approximately two. The DFT calculations constructed a structure of HFA with the formula of Fe(HAsO4)x(H2AsO4)1-x(OH)y•zH2O...
October 24, 2016: Environmental Science & Technology
Morteza Behnam, Hossein Pourghassem
BACKGROUND: EEG signal analysis of pediatric patients plays vital role for making a decision to intervene in presurgical stages. NEW METHOD: In this paper, an offline seizure detection algorithm based on definition of a seizure-specific wavelet (Seizlet) is presented. After designing the Seizlet, by forming cone of influence map of the EEG signal, four types of layouts are analytically designed that are called Seizure Modulus Maximas Patterns (SMMP). By mapping CorrEntropy Induced Metric (CIM) series, four structural features based on least square estimation of fitted non-tilt conic ellipse are extracted that are called CorrEntropy Ellipse Features (CEF)...
October 18, 2016: Journal of Neuroscience Methods
Shasha Yuan, Weidong Zhou, Junhui Li, Qi Wu
Epilepsy is a serious chronic neurological disorder, which affects more than 50 million people worldwide, and automatic seizure detection on EEG recordings is extremely required in the diagnosis and monitoring of epilepsy. This paper presents a novel seizure detection method using sparse representation-based Earth Mover's Distance (SR-EMD). In the proposed algorithm, wavelet decomposition is executed on the original EEG recordings with five scales, and the scales 3, 4 and 5 are selected to structure the distributions of EEG signals...
October 20, 2016: Medical & Biological Engineering & Computing
Sohag Biswas, Bhabani S Mallik
We present the characteristic proton transfer process from water to the pyrazole anion, infrared signatures of hydroxyl groups and the free energy profile of the process in aqueous solution combining first principles simulations, wavelet analysis and metadynamics. Our results show that the presence of minimum three water molecules in the gas phase cluster with a particular arrangement is sufficient to facilitate the proton transfer process from water to the anion. The overall reaction is very rapid in aqueous solution, and the free energy barrier for this process is found to be 4...
October 21, 2016: Physical Chemistry Chemical Physics: PCCP
Kaori Tamura, Takaaki Mizuba, Tsuyoshi Okamoto, Mayumi Matsufuji, Sachio Takashima, Keiji Iramina
INTRODUCTION: The level of residual cognitive function in patients with early brain injury is a key factor limiting rehabilitation and the quality of life. Although understanding residual function is necessary for appropriate rehabilitation, the extent of its effects on cognitive improvement remains unknown. The present study evaluated cognitive function in patients with severe motor and intellectual disabilities after early brain injuries due to cerebral hemorrhage (CH) or periventricular leukomalacia (PVL)...
October 18, 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
Hamid Abbasi, Laura Bennet, Alistair J Gunn, Charles P Unsworth
Currently, there are no developed methods to detect sharp wave transients that exist in the latent phase after hypoxia-ischemia (HI) in the electroencephalogram (EEG) in order to determine if these micro-scale transients are potential biomarkers of HI. A major issue with sharp waves in the HI-EEG is that they possess a large variability in their sharp wave profile making it difficult to build a compact 'footprint of uncertainty' (FOU) required for ideal performance of a Type-2 fuzzy logic system (FLS) classifier...
August 18, 2016: International Journal of Neural Systems
Zewei Wang, Qing Yang, Li Min Chen
The goals of this study are to characterize the temporal dynamics of inter-regional connectivity of the brain in chronic headache (CH) patients versus their age/gender matched controls (CONCH, n=28 pairs), and to determine whether dynamic measures reveal additional features to static functional connectivity and correlate with psychometric scores. Cortical thickness and inter-regional resting state fMRI connectivity were quantified and compared between CH and CONCH groups. Six cortical regions of interest (ROI) pairs that exhibited correlated cortical thickness and static functional connectivity abnormalities were selected for temporal dynamic analysis...
October 14, 2016: Magnetic Resonance Imaging
Pol Cirujeda, Yashin Dicente Cid, Henning Muller, Daniel Rubin, Todd A Aguilera, Billy W Loo, Maximilian Diehn, Xavier Binefa, Adrien Depeursinge
This paper proposes a novel imaging biomarker of lung cancer relapse from 3-D texture analysis of CT images. Three-dimensional morphological nodular tissue properties are described in terms of 3-D Riesz-wavelets. The responses of the latter are aggregated within nodular regions by means of feature covariances, which leverage rich intra- and inter- variations of the feature space dimensions. When compared to the classical use of the average for feature aggregation, feature covariances preserve spatial co-variations between features...
July 18, 2016: IEEE Transactions on Medical Imaging
Andrzej Mysiak, Małgorzata Kobusiak-Prokopowicz, Konrad Kaaz, Kamila Jarczewska, Wojciech Glabisz
BACKGROUND: The theory of chaos proves a deterministic mechanism of induction of multiple complex processes previously thought to be random in nature. This research explains how these complex processes develop. The aim of the study was to test the hypothesis of the chaotic nature of myocardial electrical events during ventricular tachycardia (VT) and ventricular fibrillation (VF). METHODS: Original hardware and software was developed for digitalization of on-line electrocardiography (ECG) data, with the functions of automatic and manual identification as well as categorization of specific ventricular arrhythmias...
October 13, 2016: Cardiology Journal
Lorenz Kahl, Ulrich G Hofmann
This work compared the performance of six different fatigue detection algorithms quantifying muscle fatigue based on electromyographic signals. Surface electromyography (sEMG) was obtained by an experiment from upper arm contractions at three different load levels from twelve volunteers. Fatigue detection algorithms mean frequency (MNF), spectral moments ratio (SMR), the wavelet method WIRM1551, sample entropy (SampEn), fuzzy approximate entropy (fApEn) and recurrence quantification analysis (RQA%DET) were calculated...
October 7, 2016: Medical Engineering & Physics
Wolfgang G Kunz, Wieland H Sommer, Lukas Havla, Franziska Dorn, Felix G Meinel, Olaf Dietrich, Grete Buchholz, Birgit Ertl-Wagner, Kolja M Thierfelder
OBJECTIVES: To determine the detection rate of intracranial vessel occlusions using CT perfusion-based wavelet-transformed angiography (waveletCTA) in acute ischemic stroke patients, in whom single-phase CTA (spCTA) failed to detect an occlusion. METHODS: Subjects were selected from a cohort of 791 consecutive patients who underwent multiparametric CT including whole-brain CT perfusion. Inclusion criteria were (1) significant cerebral blood flow (CBF) deficit, (2) no evidence of vessel occlusion on spCTA and (3) follow-up-confirmed acute ischemic infarction...
October 8, 2016: European Radiology
L Sun, J-C Xu, W Wang, Y Yin
Cancer subtype recognition and feature selection are important problems in the diagnosis and treatment of tumors. Here, we propose a novel gene selection approach applied to gene expression data classification. First, two classical feature reduction methods including locally linear embedding (LLE) and rough set (RS) are summarized. The advantages and disadvantages of these algorithms were analyzed and an optimized model for tumor gene selection was developed based on LLE and neighborhood RS (NRS). Bhattacharyya distance was introduced to delete irrelevant genes, pair-wise redundant analysis was performed to remove strongly correlated genes, and the wavelet soft threshold was determined to eliminate noise in the gene datasets...
August 30, 2016: Genetics and Molecular Research: GMR
Jitendra Chourasia, Vijay Chourasia, A K Mittra
Congenital heart defects (CHD) are one of the utmost birth defects present in the neonatal after birth and a big challenge for the researchers to identify the structural abnormality during the antepartum period. An algorithm is presented here to identify the presence of CHD through foetal phonocardiographic (fPCG) signals. The recorded fPCG is decomposed using Daubechies4 wavelet with sub-level threshold to remove the noise in the signal. The Shannon energy is used to identify the different peaks of signals and then S1 and S2 according to the intervals between adjacent peaks...
October 4, 2016: Journal of Medical Engineering & Technology
Sandeep Raj, Kailash Chandra Ray, Om Shankar
BACKGROUND AND OBJECTIVE: The increase in the number of deaths due to cardiovascular diseases (CVDs) has gained significant attention from the study of electrocardiogram (ECG) signals. These ECG signals are studied by the experienced cardiologist for accurate and proper diagnosis, but it becomes difficult and time-consuming for long-term recordings. Various signal processing techniques are studied to analyze the ECG signal, but they bear limitations due to the non-stationary behavior of ECG signals...
November 2016: Computer Methods and Programs in Biomedicine
Kh Rezaee, E Azizi, J Haddadnia
BACKGROUND: Epilepsy is a severe disorder of the central nervous system that predisposes the person to recurrent seizures. Fifty million people worldwide suffer from epilepsy; after Alzheimer's and stroke, it is the third widespread nervous disorder. OBJECTIVE: In this paper, an algorithm to detect the onset of epileptic seizures based on the analysis of brain electrical signals (EEG) has been proposed. 844 hours of EEG were recorded form 23 pediatric patients consecutively with 163 occurrences of seizures...
June 2016: Journal of Biomedical Physics & Engineering
Michael D Twa, Krystal L Schulle, Stephanie J Chiu, Sina Farsiu, David A Berntsen
PURPOSE: Spectral domain optical coherence tomography (SD-OCT) imaging permits in vivo visualization of the choroid with micron-level resolution over wide areas and is of interest for studies of ocular growth and myopia control. We evaluated the speed, repeatability, and accuracy of a new image segmentation method to quantify choroid thickness compared to manual segmentation. METHODS: Two macular volumetric scans (25 × 30°) were taken from 30 eyes of 30 young adult subjects in two sessions, 1 hour apart...
September 23, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Himani, Ratna Dahiya
In this paper, a contribution to the development of low-cost wind turbine (WT) test rig for stator fault diagnosis of wind turbine generator is proposed. The test rig is developed using a 2.5kW, 1750 RPM DC motor coupled to a 1.5kW, 1500 RPM self-excited induction generator interfaced with a WT mathematical model in LabVIEW. The performance of the test rig is benchmarked with already proven wind turbine test rigs. In order to detect the stator faults using non-stationary signals in self-excited induction generator, an online fault diagnostic technique of DWT-based multi-resolution analysis is proposed...
September 21, 2016: ISA Transactions
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