Browsing by Author "Liu, Chien-Sheng"

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Chaotic Phase Space Differential (CPSD) Algorithm for Real-Time Detection of VF, VT, and PVC ECG Signals
(2009)
Liu, Chien-Sheng
;
Lin, Yu-Chiun
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Chuang, Yueh-Hsun
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Hsiao, Tze-Chien
;
Lin, Chii-Wann
The continuous evolution of electrocardiography (ECG) recording has enabled the successful development of many significant applications of this vital signal for clinical diagnosis and monitoring. Recent trends in device miniaturization and wireless transmission have extended the uses of such a signal modality to telemedicine for home cares. However, it has posted new technical challenges for the scenarios of home users and associated business models. Among them, a smart algorithm for real time or early indication of critical cardiac conditions, e.g. ventricular fibrillation (VF), Ventricular Tachycardia (VT), are extremely important for sharing the work loads of remote side for proper responses and delivery of health care. It would be also rather critical to fit such a computation task into the wearable or mobile device for the requirement of low power consumption. In this paper, we report the development of a novel analysis algorithm based on Time-Delayed Phase Space Reconstruction (PSR) method to differentiate abnormal ECG segments from entire records. We used BIH-MIT arrhythmia database and CU database to verify our original ideas. According to our test results, this algorithm successfully identified the three heart diseases of PVC (Premature Ventricular Contraction), VF (Ventricular Fibrillation) and VT (Ventricular Tachycardia) immediately. We calculated the statistic parameters to estimate the efficiency: the average of sensitivity is 98.7% and the specificity reaches 96.2%. We also implemented this algorithm for wearable applications in a single-chip micro controller (MSP430, TI) for arrhythmia ECG data. The total code size is about a few hundred bytes and the execute time meets the order of sub-second. This new algorithm provides a powerful real-time index for clinical diagnosis and long-term home-care applications.
Education system integration in cross-disciplinary with colleges - Virtual biomedical instrument (VBI) for example
(2008-06-01)
Hsiao, Tzu-Chien
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Chang, Chia-Chi
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Liu, Chien-Sheng
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Lin, Chii-Wann
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Wang, Chih-Yu
Due to the rapid development of computer science, software, and biomedical engineering, many clinical diagnosis instruments and control system improved accordingly. The minimization and practicality of sensors, as well as the efficiency and stability of computers make simulation control system in medical instruments become the most important part of developing items. The relevant subject of course, virtual biomedical instrumentations (VBI), which combined with computer science, electrical engineering, and medical science, has become a major developing course in biomedical education. Cross-disciplinary research needs experts in different areas and most cross-disciplinary schools cannot afford it. So it requires integration and cooperation between schools. To address this issue, a graduated course has been designed to provide an opportunity for all professions in each field to discuss and share their resources on an e-learning platform. With the progress of the project, VBI course integrates biomedical education resources from north to south colleges to reduce the request of manpower for cross-disciplinary course of biomedical. In addition, VBI courses initiate the cooperation between academic community and industry.
Micro-magnetic suspension motor design for miniature optical drive
(2006-07-01)
Wang, Chien-Chang
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Yao, Yeong-Der
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Liu, Chien-Sheng
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Cheng, Lung-Yu
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交大名義發表
The main purpose of this study is to develop a low vibration micromotor applied in a miniature optical drive. To minimize the micromotor vibration, passive magnetic suspensidn technology has been used. The magnetic forces between the permanent magnets are estimated using the finite element method; the stable zone of operation of the motor developed was determined. A new micromotor with 62% of the radial vibration of the conventional micro-ball-bearing motor has been successfully developed. In addition, the new motor demonstrates lower friction torque loss.
The differential method of phase space matrix for AF/VF discrimination application
(2010-06-01)
Liu, Chien-Sheng
;
Tseng, Wei-Kung
;
Lee, Jen-Kuang
;
Hsiao, Tze-Chien
;
Lin, Chii-Wann
The advances in electrocardiographic (ECG) technology have facilitated the development of numerous successful clinical applications and commercial monitoring products for diagnosing disease and monitoring health. All of these demand the development of smart algorithms and computational resources for the real-time, early indication of critical cardiac conditions. This study presents the development of a Complex Phase Space Difference (CPSD) algorithm with differential method to analyze spatial and temporal changes in reconstructed phase space matrix, and derives an index for real-time monitoring. We used total of 5306 data segments from MIT-BIH, CU, and SCDH databases and clinical trial data to determine the optimal working parameters and verified the classification capability by using a quantitative index of this algorithm. With threshold values set to 2.0 and 6.0, this method can successfully differentiate normal sinus rhythm (NSR) signals (1.48 +/- 0.21), low risk of atrial fibrillation (AF) signals (3.71 +/- 0.99) and high risk of ventricular fibrillation (VF) signals (9.38 +/- 2.22). It is the first real-time algorithm that reports the best performance to distinguish AF and VF with sensitivity of 97.9% and specificity of 98.4%. With self-normalization, the algorithm is not subjected to the inter-variability or sampling size effects. Its computational scheme only requires matrices addition and subtraction, and thus significantly reduces the complexity for real-time implementation. It will be able to adopt in different scenarios of tele-healthcare and implantable applications. (C) 2010 IPEM. Published by Elsevier Ltd. All rights reserved.