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A thickness shear mode (TSM) sensor of which acoustic shear wave has a nano-scale penetration depth was used in detecting biological activities of living cells. The initial cell adhesion process was characterized by analyzing multi-harmonic responses of the TSM sensor. A suspension of bovine aortic endothelial cells (BAECs) was placed on the TSM sensor, and changes in impedance magnitude during sedimentation...
The extracorporeal shock wave lithotripsy (ESWL) has come into wide use due to its non-invasive advantage. However, as for the shock wave propagation in human body in relation to practical lithotripsy, there are a few studies on numerical simulation based on models conforming to practical situations. In this paper we report a numerical method of finite difference time domain (FDTD) for analyzing ultrasonic...
This paper introduces a novel hearing aid named artificial ultrasonic bone conduction hearing device, which is different from the traditional hearing aid in two sides: 1) sound conduction manner, 2) human perceptive principles. We focus on discussing the structure of the hearing aid and the research of frequency transposition algorithm. In addition, we design algorithm experimental platform and some...
A kind of remote monitoring system on heart sound is constructed, which can tele-monitor ECG and PCG. The system integrates embedded Internet technology and wireless technology. As it can send ECG and PCG by Internet, it realizes real-time recording and monitoring of physiology parameter of patients at low cost and both at home and in hospital, and it also can be used for analysis for computer or...
In this paper, it is shown that the main source of mechanical energy of cardiovascular (CV) system i.e., rhythmic heart contraction is transformed to the oscillations of the CV walls and blood flow, and finally CV acoustical waves. These waves propagate through both blood flow (hemodynamical pathways) and tissues (viscoelastical pathways) toward the skin. Nonetheless, the CV walls could be assumed...
Several studies have shown differences in spectral parameters between simple snorers and patients with obstructive sleep apnea syndrome (OSAS). Most of them analyzed a reduced number of snores and/or only post-apneic snores were selected in OSAS patients. Previous findings suggest that snore parameters have a greater variability as the severity of OSAS increases. In this work we propose to analyze...
Heart beat is an unavoidable source of interference during lung sound recording. This disturbance is more significant at low and medium breathing flow rates. Removing heart sounds (HS) from lung sound recordings or vice versa is a challenging task but of great interest for respiratory specialists and cardiologists. In this study, to separate the two signals, a novel HS separation method based on independent...
Last year at the EMBC 2004 in San Francisco, we presented a paper entitled: "Digital Phonocardiography: a PDA-based Approach", which introduced the development of a PDA-based biomedical instrument capable of acquiring, processing, and analysis of heart sounds. In this paper we present a system, which is not only able to record and display the heart sounds in a pocket PC but also apply several...
MedScanSonics Inc. (MS2)'s CADSCANreg and acoustic ISOMACreg sensors combine state-of-the-art non-invasive acoustic sensing and proprietary wavelet transform algorithms with fast DSP core hardware to quickly detect and locate coronary arterial stenoses with near-pinpoint accuracy in real-time
A novel compact method for fetal home monitoring optimized for long data acquisition time and low communication costs is presented. The method incorporates the preprocessing of disturbed acoustic signal received on the maternal abdomen. The basic idea of the preprocessing is that the detection of the systolic and diastolic sounds takes place on two separated frequency bands with autocorrelation on...
With the increasing performance of computer, the virtual instrument technology has greatly advanced over the years, and then virtual medical instrument technology becomes available. This paper presents the virtual medical instrument, and then as an example, an application of a signal acquisition, processing and analysis system using LabVIEW is also given
In this study, average power of tracheal sound (Pave) was used to estimate flow by parametric method as well as adaptive filters as a nonparametric method. Based on some preliminary studies, an exponential model was used for describing the relationship between flow and Pave for parametric method. It was assumed that flow signal of at least one breath from each target flow is available for calibration...
A segmentation algorithm, which detects a single cardiac cycle (S 1-systole-S2-diastole) of phonocardiogram (PCG) signals using homomorphic filtering and K-means clustering and a three way classification of heart sounds into normal (N), systolic murmur (S) and diastolic murmur (D) using grow and learn (GAL) neural network, are presented. Homomorphic filtering converts a non-linear combination of signals...
The left-ventricle ejection fraction is an important cardiac-efficiency measure that is regularly used in cardiology. Standard estimations are based on time-consuming geometrical analysis and modelling, which requires experienced cardiologists. Alternative methods are very invasive due to the need for cardiac catheterization. In this paper we present and study a minimally-invasive indicator dilution...
This paper describes a method for extracting features from a phonocardiogram to be used by an expert system for diagnostic purposes. The key issue is to choose features which match with the doctor's (expert's) diagnostic approach. Only in that way can the knowledge of the expert be effectively coded into rules within an expert system
This paper presents an algorithm for accurate and improved detection of the first heart sound S1 for heart sound cardiac cycle segmentation under noisy environments. The proposed algorithm integrates an S1/S2 selection step and an S1 identification step. An adaptive sub-level tracking algorithm based on wavelet transform is proposed to separate the S1 and S2 from other components such as murmurs...
Noninvasive diagnosis method of coronary artery disease is proposed based on the instantaneous frequency estimate of diastolic murmurs and support vector machine(SVM) classifier. Hilbert-Huang transform is studied to analyze the instantaneous frequency of diastolic murmurs. The weighted instantaneous frequency is introduced. Using statistical quantities of weighted instantaneous frequency forms feature...
EMG-based VAD is proposed. It is generally known that EMG signals are not affected by acoustic noise and preceding voice. Robust but preceding detection of speech can be expected by using these features. The proposed method extracts one VAD parameter to judge speech or silence from among n EMG signal channels. Experiments are performed to confirm the effectiveness of the proposed method. The results...
The objective was to test the robustness of an acoustic method to estimate respiratory rates (RR) during treadmill test. The accuracy was assessed by the comparison with simultaneous estimates from a capnograph, using as a common reference a pneumotachometer. Eight subjects without any pulmonary disease were enrolled. Tracheal sounds were acquired using a contact piezoelectric sensor placed on the...
Respiratory sound analysis can offer important information related to pulmonary diseases. Wheezes have been reported as adventitious respiratory sounds in asthmatic or obstructive patients, during forced exhalation maneuvers. In this work, we propose a method for monitoring and analysis of respiratory sounds in frequency domain, during spontaneous ventilation. The database analyzed was acquired during...
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