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    Noninvasive fetal ECG extraction using doubly constrained block-term decomposition

    , Article Mathematical Biosciences and Engineering ; Volume 17, Issue 1 , 2020 , Pages 144-159 Mousavian, I ; Shamsollahi, M. B ; Fatemizadeh, E ; Sharif University of Technology
    American Institute of Mathematical Sciences  2020
    Fetal electrocardiogram (fECG) monitoring is a beneficial method for assessing fetal health and diagnosing the fetal cardiac condition during pregnancy. In this study, an algorithm is proposed to extract fECG from maternal abdominal signals based on doubly constrained block-term (DoCoBT) tensor decomposition. This tensor decomposition method is constrained by quasi-periodicity constraints of fetal and maternal ECG signals. Tensor decompositions are more powerful tools than matrix decomposition, due to employing more information for source separation. Tensorizing abdominal signals and using periodicity constraints of fetal and maternal ECG, appropriately separates subspaces of the mother, the... 

    The application of empirical mode decomposition for the enhancement of cardiotocograph signals

    , Article Physiological Measurement ; Volume 30, Issue 8 , 2009 , Pages 729-743 ; 09673334 (ISSN) Krupa, B. N ; Mohd Ali, M. A ; Zahedi, E ; Sharif University of Technology
    Cardiotocograph (CTG) is widely used in everyday clinical practice for fetal surveillance, where it is used to record fetal heart rate (FHR) and uterine activity (UA). These two biosignals can be used for antepartum and intrapartum fetal monitoring and are, in fact, nonlinear and non-stationary. CTG recordings are often corrupted by artifacts such as missing beats in FHR, high-frequency noise in FHR and UA signals. In this paper, an empirical mode decomposition (EMD) method is applied on CTG signals. A recursive algorithm is first utilized to eliminate missing beats. High-frequency noise is reduced using EMD followed by the partial reconstruction (PAR) method, where the noise order is... 

    Applicability of adaptive noise cancellation to fetal heart rate detection using photoplethysmography

    , Article Computers in Biology and Medicine ; Volume 38, Issue 1 , 2008 , Pages 31-41 ; 00104825 (ISSN) Zahedi, E ; Beng, G. K ; Sharif University of Technology
    In this paper, an approach based on adaptive noise cancellation (ANC) is evaluated for extraction of the fetal heart rate using photoplethysmographic signals from the maternal abdomen. A simple optical model is proposed in which the maternal and fetal blood pulsations result in emulated signals where the lower SNR limit (fetal to maternal) is - 25 dB. It is shown that a recursive least-squares algorithm is capable of extracting the peaks of the fetal PPG from these signals, for typical values of maternal and fetal tissues. © 2007 Elsevier Ltd. All rights reserved  

    Transabdominal fetal heart rate detection using NIR photopleythysmography: instrumentation and clinical results

    , Article IEEE Transactions on Biomedical Engineering ; Volume 56, Issue 8 , 2009 , Pages 2075-2082 ; 00189294 (ISSN) Gan, K. B ; Zahedi, E ; Mohd Ali, M. A ; Sharif University of Technology
    In obstetrics, fetal heart rate (FHR) detection remains the standard for intrapartum assessment of fetal well-being. In this paper, a low-power (<55 mW) optical technique is proposed for transabdominal FHR detection using near-infrared photoplesthys-mography (PPG). A beam of IR-LED (890 nm) propagates through to the maternal abdomen and fetal tissues, resulting in a mixed signal detected by a low-noise detector situated at a distance of 4 cm. Low-noise amplification and 24-bit analog-to-digital converter resolution ensure minimum effect of quantization noise. After synchronous detection, the mixed signal is processed by an adaptive filter to extract the fetal signal, whereas the PPG from the... 

    Interaction analysis of a pregnant female uterus and fetus in a vehicle passing a speed bump

    , Article Journal of Biomechanics ; Volume 118 , March , 2021 ; 00219290 (ISSN) Irannejad Parizi, M ; Ahmadian, M. T ; Mohammadi, H ; Sharif University of Technology
    Elsevier Ltd  2021
    Pregnant vehicle occupants experience relatively large acceleration when the vehicle passes a speed-bump. In this paper, the effect of such sudden acceleration on a pregnant uterus is investigated. A biomechanical model representing the fundamental dynamic behaviors of a pregnant uterus has been developed. The model relates to the 32nd week of gestation when the fetus is in head-down, occipito-anterior position. Considering the drag and squeeze effects of the amniotic fluid, we derive a comprehensive differential equation that represents the interaction of the uterus and fetus. Solving the governing equation, we obtain the system response to different speed-bump excitations. Using the fetal... 

    Antepartum fetal heart rate feature extraction and classification using empirical mode decomposition and support vector machine

    , Article BioMedical Engineering Online ; Volume 10 , 2011 ; 1475925X (ISSN) Krupa, N ; MA, M. A ; Zahedi, E ; Ahmed, S ; Hassan, F. M ; Sharif University of Technology
    Background: Cardiotocography (CTG) is the most widely used tool for fetal surveillance. The visual analysis of fetal heart rate (FHR) traces largely depends on the expertise and experience of the clinician involved. Several approaches have been proposed for the effective interpretation of FHR. In this paper, a new approach for FHR feature extraction based on empirical mode decomposition (EMD) is proposed, which was used along with support vector machine (SVM) for the classification of FHR recordings as 'normal' or 'at risk'.Methods: The FHR were recorded from 15 subjects at a sampling rate of 4 Hz and a dataset consisting of 90 randomly selected records of 20 minutes duration was formed from... 

    Modeling and Analysis of Pregnant Women Uterus Under Vehicle Vibrations

    , Ph.D. Dissertation Sharif University of Technology Irannejad Parizi, Mostafa (Author) ; Ahmadian, Mohammad Taghi (Supervisor) ; Firoozbakhsh, Keikhosrow (Co-Supervisor) ; Mohammadi, Hadi (Co-Supervisor)
    Nowadays, the use of vehicles is inevitable for all people including pregnant females. Vehicle vibrations during passing road bumps and holes is one of the pregnant females’ concerns. The aim of the present study is to develop a biomechanical model of a Uterus and Fetus Set (UFS) to evaluate its response to the inferior excitation, caused by the vehicle passing over speed bumps. The most important innovation of this research is "Analysis of the effect of vehicle speed and speed bumps characteristics on the risk of injury to the fetus." "Modeling the pregnant uterus complex separately from other abdominal organs", "Biomechanical modeling based on CT scan data from a real subject", "Providing... 

    Rigid-bar loading on pregnant uterus and development of pregnant abdominal response corridor based on finite element biomechanical model

    , Article International Journal for Numerical Methods in Biomedical Engineering ; Volume 36, Issue 1 , January , 2020 Irannejad Parizi, M ; Ahmadian, M. T ; Mohammadi, H ; Sharif University of Technology
    Wiley-Blackwell  2020
    During pregnancy, traumas can threaten maternal and fetal health. Various trauma effects on a pregnant uterus are little investigated. In the present study, a finite element model of a uterus along with a fetus, placenta, amniotic fluid, and two most effective ligament sets is developed. This model allows numerical evaluation of various loading on a pregnant uterus. The model geometry is developed based on CT-scan data and validated using anthropometric data. Applying Ogden hyper-elastic theory, material properties of uterine wall and placenta are developed. After simulating the “rigid-bar” abdominal loading, the impact force and abdominal penetration are investigated. Findings are compared...