keyword
MENU ▼
Read by QxMD icon Read
search

Wavelet analysis

keyword
https://www.readbyqxmd.com/read/28729684/combining-low-dimensional-wavelet-features-and-support-vector-machine-for-arrhythmia-beat-classification
#1
Qin Qin, Jianqing Li, Li Zhang, Yinggao Yue, Chengyu Liu
Automatic feature extraction and classification are two main tasks in abnormal ECG beat recognition. Feature extraction is an important prerequisite prior to classification since it provides the classifier with input features, and the performance of classifier depends significantly on the quality of these features. This study develops an effective method to extract low-dimensional ECG beat feature vectors. It employs wavelet multi-resolution analysis to extract time-frequency domain features and then applies principle component analysis to reduce the dimension of the feature vector...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724978/economic-factors-influencing-zoonotic-disease-dynamics-demand-for-poultry-meat-and-seasonal-transmission-of-avian-influenza-in-vietnam
#2
Alexis Delabouglise, Marc Choisy, Thang D Phan, Nicolas Antoine-Moussiaux, Marisa Peyre, Ton D Vu, Dirk U Pfeiffer, Guillaume Fournié
While climate is often presented as a key factor influencing the seasonality of diseases, the importance of anthropogenic factors is less commonly evaluated. Using a combination of methods - wavelet analysis, economic analysis, statistical and disease transmission modelling - we aimed to explore the influence of climatic and economic factors on the seasonality of H5N1 Highly Pathogenic Avian Influenza in the domestic poultry population of Vietnam. We found that while climatic variables are associated with seasonal variation in the incidence of avian influenza outbreaks in the North of the country, this is not the case in the Centre and the South...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28717523/assessment-of-emotional-expressions-after-full-face-transplantation
#3
Çağdaş Topçu, Hilmi Uysal, Ömer Özkan, Özlenen Özkan, Övünç Polat, Merve Bedeloğlu, Arzu Akgül, Ela Naz Döğer, Refik Sever, Nur Ebru Barçın, Kadriye Tombak, Ömer Halil Çolak
We assessed clinical features as well as sensory and motor recoveries in 3 full-face transplantation patients. A frequency analysis was performed on facial surface electromyography data collected during 6 basic emotional expressions and 4 primary facial movements. Motor progress was assessed using the wavelet packet method by comparison against the mean results obtained from 10 healthy subjects. Analyses were conducted on 1 patient at approximately 1 year after face transplantation and at 2 years after transplantation in the remaining 2 patients...
2017: Neural Plasticity
https://www.readbyqxmd.com/read/28705145/texture-based-classification-of-different-single-liver-lesion-based-on-spair-t2w-mri-images
#4
Zhenjiang Li, Yu Mao, Wei Huang, Hongsheng Li, Jian Zhu, Wanhu Li, Baosheng Li
BACKGROUND: To assess the feasibility of texture analysis (TA) based on spectral attenuated inversion-recovery T2 weighted magnetic resonance imaging (SPAIR T2W-MRI) for the classification of hepatic hemangioma (HH), hepatic metastases (HM) and hepatocellular carcinoma (HCC). METHODS: The SPAIR T2W-MRI data of 162 patients with HH (n=55), HM (n=67) and HCC (n=40) were retrospectively analyzed. We used two independent cohorts for training (n = 112 patients) and validation (n = 50 patients)...
July 13, 2017: BMC Medical Imaging
https://www.readbyqxmd.com/read/28704495/space-time-analysis-of-pneumonia-hospitalisations-in-the-netherlands
#5
Elisa Benincà, Michiel van Boven, Thomas Hagenaars, Wim van der Hoek
Community acquired pneumonia is a major global public health problem. In the Netherlands there are 40,000-50,000 hospital admissions for pneumonia per year. In the large majority of these hospital admissions the etiologic agent is not determined and a real-time surveillance system is lacking. Localised and temporal increases in hospital admissions for pneumonia are therefore only detected retrospectively and the etiologic agents remain unknown. Here, we perform spatio-temporal analyses of pneumonia hospital admission data in the Netherlands...
2017: PloS One
https://www.readbyqxmd.com/read/28700903/computer-based-classification-of-chromoendoscopy-images-using-homogeneous-texture-descriptors
#6
Hussam Ali, Muhammad Sharif, Mussarat Yasmin, Mubashir Husain Rehmani
Computer-aided analysis of clinical pathologies is a challenging task in the field of medical imaging. Specifically, the detection of abnormal regions in the frames collected during an endoscopic session is difficult. The variations in the conditions of image acquisition, such as field of view or illumination modification, make it more demanding. Therefore, the design of a computer-assisted diagnostic system for the recognition of gastric abnormalities requires features that are robust to scale, rotation, and illumination variations of the images...
July 5, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28692997/automated-classification-and-removal-of-eeg-artifacts-with-svm-and-wavelet-ica
#7
Chong Yeh Sai, Norrima Mokhtar, Hamzah Arof, Paul Cumming, Masahiro Iwahashi
Brain electrical activity recordings by electroencephalography (EEG) are often contaminated with signal artifacts. Procedures for automated removal of EEG artifacts are frequently sought for clinical diagnostics and brain computer interface (BCI) applications. In recent years, a combination of independent component analysis (ICA) and discrete wavelet transform (DWT) has been introduced as standard technique for EEG artifact removal. However, in performing the wavelet-ICA procedure, visual inspection or arbitrary thresholding may be required for identifying artifactual components in the EEG signal...
July 4, 2017: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28692691/extracting-time-frequency-feature-of-single-channel-vastus-medialis-emg-signals-for-knee-exercise-pattern-recognition
#8
Yi Zhang, Peiyang Li, Xuyang Zhu, Steven W Su, Qing Guo, Peng Xu, Dezhong Yao
The EMG signal indicates the electrophysiological response to daily living of activities, particularly to lower-limb knee exercises. Literature reports have shown numerous benefits of the Wavelet analysis in EMG feature extraction for pattern recognition. However, its application to typical knee exercises when using only a single EMG channel is limited. In this study, three types of knee exercises, i.e., flexion of the leg up (standing), hip extension from a sitting position (sitting) and gait (walking) are investigated from 14 healthy untrained subjects, while EMG signals from the muscle group of vastus medialis and the goniometer on the knee joint of the detected leg are synchronously monitored and recorded...
2017: PloS One
https://www.readbyqxmd.com/read/28685918/a-long-term-bci-study-with-ecog-recordings-in-freely-moving-rats
#9
Thomas Costecalde, Tetiana Aksenova, Napoleon Torres-Martinez, Andriy Eliseyev, Corinne Mestais, Cecile Moro, Alim Louis Benabid
BACKGROUND: Brain Computer Interface (BCI) studies are performed in an increasing number of applications. Questions are raised about electrodes, data processing and effectors. Experiments are needed to solve these issues. OBJECTIVE: To develop a simple BCI set-up to easier studies for improving the mathematical tools to process the ECoG to control an effector. METHOD: We designed a simple BCI using transcranial electrodes (17 screws, three mechanically linked to create a common reference, 14 used as recording electrodes) to record Electro-Cortico-Graphic (ECoG) neuronal activities in rodents...
July 6, 2017: Neuromodulation: Journal of the International Neuromodulation Society
https://www.readbyqxmd.com/read/28683095/computer-algorithms-for-automated-detection-and-analysis-of-local-ca2-releases-in-spontaneously-beating-cardiac-pacemaker-cells
#10
Alexander V Maltsev, Sean P Parsons, Mary S Kim, Kenta Tsutsui, Michael D Stern, Edward G Lakatta, Victor A Maltsev, Oliver Monfredi
Local Ca2+ Releases (LCRs) are crucial events involved in cardiac pacemaker cell function. However, specific algorithms for automatic LCR detection and analysis have not been developed in live, spontaneously beating pacemaker cells. In the present study we measured LCRs using a high-speed 2D-camera in spontaneously contracting sinoatrial (SA) node cells isolated from rabbit and guinea pig and developed a new algorithm capable of detecting and analyzing the LCRs spatially in two-dimensions, and in time. Our algorithm tracks points along the midline of the contracting cell...
2017: PloS One
https://www.readbyqxmd.com/read/28676672/study-on-optimal-selection-of-wavelet-vanishing-moments-for-ecg-denoising
#11
Ziran Peng, Guojun Wang
The frequency characteristics of wavelets and the vanishing moments of wavelet filters are both important parameters of wavelets. Clarifying the relationship between the wavelet frequency characteristics and the vanishing moments of the wavelet filter can provide a theoretical basis for selecting the best wavelet. In this paper, the frequency characteristics of wavelets were analyzed by mathematical modeling, the mathematical relationship between wavelet frequency characteristics and vanishing moments was clarified, the optimal wavelet base function was selected hierarchically according to the amplitude frequency characteristics of ECG signal, and an accurate notch filter was realized according to the frequency characteristics of the noise...
July 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28675778/hip-abductor-muscle-activity-during-walking-in-individuals-with-gluteal-tendinopathy
#12
Kim Allison, Sauro E Salomoni, Kim L Bennell, Tim V Wrigley, Francois Hug, Bill Vicenzino, Alison Grimaldi, Paul W Hodges
The external hip adduction moment during walking is greater in individuals with gluteal tendinopathy (GT) than pain-free controls. Although this likely represents a greater demand on the hip abductor muscles implicated in GT, no study has investigated activation of these muscles in GT. For this purpose, fine wire electrodes were inserted into the segments of the gluteus minimus and medius muscles, and surface electrodes placed on the tensor fascia lata, upper gluteus maximus and vastus lateralis muscles of thirteen individuals with, and thirteen without, GT...
July 4, 2017: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/28675748/a-preliminary-study-for-the-assessment-of-hypertension-using-static-and-dynamic-ir-thermograms
#13
Jayanthi Thiruvengadam, Anburajan Mariamichael
Structural changes in blood vessels occur due to prolonged hypertension. Early detection of blood pressure (mm Hg) is essential for disease prevention. The aim of this work is to propose a computer-aided diagnostic (CADx) model for the diagnosis of hypertension using variables derived from non-contact static and dynamic thermal imaging in comparison with the pulse wave velocity (PWV)-derived parameters. Static and dynamic infrared (IR) thermograms of selected skin areas of the body from known hypertensive (n=14) and age- and sex-matched normal subjects were captured...
July 4, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28674650/an-adaptive-singular-spectrum-analysis-method-for-extracting-brain-rhythms-of-electroencephalography
#14
Hai Hu, Shengxin Guo, Ran Liu, Peng Wang
Artifacts removal and rhythms extraction from electroencephalography (EEG) signals are important for portable and wearable EEG recording devices. Incorporating a novel grouping rule, we proposed an adaptive singular spectrum analysis (SSA) method for artifacts removal and rhythms extraction. Based on the EEG signal amplitude, the grouping rule determines adaptively the first one or two SSA reconstructed components as artifacts and removes them. The remaining reconstructed components are then grouped based on their peak frequencies in the Fourier transform to extract the desired rhythms...
2017: PeerJ
https://www.readbyqxmd.com/read/28672026/weibo-sentiments-and-stock-return-a-time-frequency-view
#15
Yingying Xu, Zhixin Liu, Jichang Zhao, Chiwei Su
This study provides new insights into the relationships between social media sentiments and the stock market in China. Based on machine learning, we classify microblogs posted on Sina Weibo, a Twitter's variant in China into five detailed sentiments of anger, disgust, fear, joy, and sadness. Using wavelet analysis, we find close positive linkages between sentiments and the stock return, which have both frequency and time-varying features. Five detailed sentiments are positively related to the stock return for certain periods, particularly since October 2014 at medium to high frequencies of less than ten trading days, when the stock return is undergoing significant fluctuations...
2017: PloS One
https://www.readbyqxmd.com/read/28658260/spatiotemporal-variability-and-environmental-factors-of-harmful-algal-blooms-habs-over-western-lake-erie
#16
Di Tian, Gengxin Xie, Jing Tian, Kuo-Hsin Tseng, C K Shum, Jiyoung Lee, Song Liang
Over the past decades, numerous studies have been carried out in understanding causes of Harmful Algal Blooms (HABs) and their dynamics, yielding great knowledge in this field. Lake Erie, the fourth-largest lake of the five Great Lake, is among those highly vulnerable to the impacts of HABs and has received substantial attention from the public, water management sectors, and academic field. Building upon previous work, this study aims to characterize spatiotemporal variability of Chlorophyll a (Chl-a), which is an important indicator of HABs, and to explore relative importance of environmental factors associated with HABs in the west Lake Erie...
2017: PloS One
https://www.readbyqxmd.com/read/28654638/increased-inspiratory-resistance-affects-the-dynamic-relationship-between-blood-pressure-changes-and-subarachnoid-space-width-oscillations
#17
Magdalena Wszedybyl-Winklewska, Jacek Wolf, Ewa Swierblewska, Katarzyna Kunicka, Kamila Mazur, Marcin Gruszecki, Pawel J Winklewski, Andrzej F Frydrychowski, Leszek Bieniaszewski, Krzysztof Narkiewicz
BACKGROUND AND OBJECTIVE: Respiration is known to affect cerebrospinal fluid (CSF) movement. We hypothesised that increased inspiratory resistance would affect the dynamic relationship between blood pressure (BP) changes and subarachnoid space width (SAS) oscillations. METHODS: Experiments were performed in a group of 20 healthy volunteers undergoing controlled intermittent Mueller Manoeuvres (the key characteristic of the procedure is that a studied person is subjected to a controlled, increased inspiratory resistance which results in marked potentiation of the intrathoracic negative pressure)...
2017: PloS One
https://www.readbyqxmd.com/read/28653015/classification-of-breast-masses-in-ultrasound-images-using-self-adaptive-differential-evolution-extreme-learning-machine-and-rough-set-feature-selection
#18
Kadayanallur Mahadevan Prabusankarlal, Palanisamy Thirumoorthy, Radhakrishnan Manavalan
A method using rough set feature selection and extreme learning machine (ELM) whose learning strategy and hidden node parameters are optimized by self-adaptive differential evolution (SaDE) algorithm for classification of breast masses is investigated. A pathologically proven database of 140 breast ultrasound images, including 80 benign and 60 malignant, is used for this study. A fast nonlocal means algorithm is applied for speckle noise removal, and multiresolution analysis of undecimated discrete wavelet transform is used for accurate segmentation of breast lesions...
April 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28649965/pawflim-reducing-bias-and-uncertainty-to-enable-lower-photon-count-in-flim-experiments
#19
Mauro Silberberg, Hernán E Grecco
Förster resonant energy transfer measured by fluorescence lifetime imaging microscopy (FRET-FLIM) is the method of choice for monitoring the spatio-temporal dynamics of protein interactions in living cells. To obtain an accurate estimate of the molecular fraction of interacting proteins requires a large number of photons, which usually precludes the observation of a fast process, particularly with time correlated single photon counting (TCSPC) based FLIM. In this work, we propose a novel method named pawFLIM (phasor analysis via wavelets) that allows the denoising of FLIM datasets by adaptively and selectively adjusting the desired compromise between spatial and molecular resolution...
June 26, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28643516/untargeted-comprehensive-two-dimensional-liquid-chromatography-coupled-with-high-resolution-mass-spectrometry-analysis-of-rice-metabolome-using-multivariate-curve-resolution
#20
Meritxell Navarro-Reig, Joaquim Jaumot, Anna Baglai, Gabriel Vivó-Truyols, Peter J Schoenmakers, Romà Tauler
In this work, a new strategy for the chemometric analysis of two-dimensional liquid chromatography-high-resolution mass spectrometry (LC × LC-HRMS) data is proposed. This approach consists of a preliminary compression step along the mass spectrometry (MS) spectral dimension based on the selection of the regions of interest (ROI), followed by a further data compression along the chromatographic dimension by wavelet transforms. In a secondary step, the multivariate curve resolution alternating least squares (MCR-ALS) method is applied to previously compressed data sets obtained in the simultaneous analysis of multiple LC × LC-HRMS chromatographic runs from multiple samples...
July 7, 2017: Analytical Chemistry
keyword
keyword
58570
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"