Browsing by Author "Chen, Ya-Chen"

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Abdominal Breathing by Using an Intelligent Tutoring System
(2015-01-01)
Chen, Ya-Chen
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Hsiao, Tzu-Chien
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資訊工程學系
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Department of Computer Science
With the growing number of aging population, abdominal breathing (AB) as a health-promoting exercise has claimed wide human interest. Especially in Asia, AB becomes a friendly practice in traditional medicine, for instance, a gentle spiritual exercise of Tai Chi Chuan (), a combination of breathing exercise, relaxation and meditation of Chi Kung (), and different yoga-type breathing patterns. Most of experienced mentors advise learners memorizing AB step by step. However, it is hard to retrieve for learners to practice AB by themselves. Within this paper, we present an iso-volume maneuver (IVM) tutoring system based on learning by doing for subjects to learn AB. During the IVM, subjects focus on the abdominal wall movement, and remember the AB pattern by observing respiratory signals in this system. The IVM tutoring system also measures the respiratory signals by respiratory inductive plethysmography and calculates the energy proportion of abdominal wall movement signals (E-awm) to evaluate the performance of AB learning. The higher E-awm represents the more correct practicing AB. A 50 subjects\' experiment which divided subjects into IVM and non-IVM groups (learning AB with step by step instructions) is introduced in this study. Results indicate that IVM group has significant higher E-awm (59.5 +/- 6.0%) than the non-IVM group (51.6 +/- 10.4%). Therefore, the IVM group performs better AB than the non-IVM group. We conclude that the IVM tutoring system is efficient for individual to learn AB.
Better Thoracoabdominal Synchrony in Abdominal Breathing: Evidence From Complementary Ensemble Empirical Mode Decomposition-Based Lissajous Figure Analysis
(2015-04-01)
Chen, Ya-Chen
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Hsiao, Tzu-Chien
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Chen, Jin-Long
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分子醫學與生物工程研究所
;
資訊工程學系
Abdominal breathing (AB) is believed to be a healthier pattern of breathing than thoracic breathing (TB). However, the objective evidence is scanty. Thoracoabdominal synchrony could be evaluated by calculating the phase angle between rib cage and abdomen motion in the Lissajous figure. A lesser phase angle indicates a better thoracoabdominal synchrony. Complementary ensemble empirical mode decomposition (CEEMD) was recently developed to extract the main component in the nonlinear and non-stationary signals. This study was designed to compare the thoracoabdominal synchrony between AB and TB via a CEEMD-based Lissajous figure analysis. Twenty-nine healthy subjects [24 males and 5 females; age 22 (21-23) years, median (interquartile range)] were recruited to receive simultaneous respiratory inductive plethysmography recording of rib cage and abdomen motion during AB and TB respectively. The main components of rib cage and abdomen motion were extracted by CEEMD. These main components were used to plot the Lissajous figure and calculate the phase angle. Compared with TB, AB revealed a significant decrease (P < 0.001) in phase angle [AB 12.13 (8.70-15.76)degrees vs. TB 22.56 (17.59-26.35)degrees]. In conclusion, AB assumes a better thoracoabdominal synchrony than TB. This finding might help to explain why AB is a healthier pattern of breathing. In addition, the CEEMD-based Lissajous figure analysis could be an effective method for the evaluation of thoracoabdominal synchrony.
Development of LabVIEW Based Micro Computed Tomography System on Vertical Rotary Gantry
(2015-01-01)
Tu, Shih-Huan
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Chen, Ya-Chen
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Hsiao, Tzu-Chien
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Jin, Shih-Chun
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Chen, Jyh-Cheng
Construction of a micro computed tomography (micro-CT) system has been proposed and developed in recent years. For the need of exploring and investigating a novel computed tomography (CT) image reconstruction method, custom-built micro-CT system offers a corresponding laboratory research environment. To develop a controllable program capable of incorporating with different devices efficiently, we use Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW), a graphical programming language, as our programming environment to implement micro-CT system on vertical rotary gantry. We scanned and reconstructed the 360 projections derived from full 360 degrees scan with angular stepping of 1 degrees. Total scan time is about 9.1 minutes. We will combine micro fluorescence tomography (micro-FT) and micro-CT on uni-platform in the future.
Development of Limited-Angle Iterative Reconstruction Algorithms with Context Encoder-Based Sinogram Completion for Micro-CT Applications
(2018-12-01)
Jin, Shih-Chun
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Hsieh, Chia-Jui
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Chen, Jyh-Cheng
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Tu, Shih-Huan
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Chen, Ya-Chen
Limited-angle iterative reconstruction (LAIR) reduces the radiation dose required for computed tomography (CT) imaging by decreasing the range of the projection angle. We developed an image-quality-based stopping-criteria method with a flexible and innovative instrument design that, when combined with LAIR, provides the image quality of a conventional CT system. This study describes the construction of different scan acquisition protocols for micro-CT system applications. Fully-sampled Feldkamp (FDK)-reconstructed images were used as references for comparison to assess the image quality produced by these tested protocols. The insufficient portions of a sinogram were inpainted by applying a context encoder (CE), a type of generative adversarial network, to the LAIR process. The context image was passed through an encoder to identify features that were connected to the decoder using a channel-wise fully-connected layer. Our results evidence the excellent performance of this novel approach. Even when we reduce the radiation dose by 1/4, the iterative-based LAIR improved the full-width half-maximum, contrast-to-noise and signal-to-noise ratios by 20% to 40% compared to a fully-sampled FDK-based reconstruction. Our data support that this CE-based sinogram completion method enhances the efficacy and efficiency of LAIR and that would allow feasibility of limited angle reconstruction.
Instantaneous phase difference analysis between thoracic and abdominal movement signals based on complementary ensemble empirical mode decomposition
(2016-10-06)
Chen, Ya-Chen
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Hsiao, Tzu-Chien
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分子醫學與生物工程研究所
;
資訊工程學系
;
生醫電子轉譯研究中心
Background: Thoracoabdominal asynchrony is often adopted to discriminate respiratory diseases in clinics. Conventionally, Lissajous figure analysis is the most frequently used estimation of the phase difference in thoracoabdominal asynchrony. However, the temporal resolution of the produced results is low and the estimation error increases when the signals are not sinusoidal. Other previous studies have reported time-domain procedures with the use of band-pass filters for phase-angle estimation. Nevertheless, the band-pass filters need calibration for phase delay elimination. Methods: To improve the estimation, we propose a novel method (named as instantaneous phase difference) that is based on complementary ensemble empirical mode decomposition for estimating the instantaneous phase relation between measured thoracic wall movement and abdominal wall movement. To validate the proposed method, experiments on simulated time series and human-subject respiratory data with two breathing types (i.e., thoracic breathing and abdominal breathing) were conducted. Latest version of Lissajous figure analysis and automatic phase estimation procedure were compared. Results: The simulation results show that the standard deviations of the proposed method were lower than those of two other conventional methods. The proposed method performed more accurately than the two conventional methods. For the human-subject respiratory data, the results of the proposed method are in line with those in the literature, and the correlation analysis result reveals that they were positively correlated with the results generated by the two conventional methods. Furthermore, the standard deviation of the proposed method was also the smallest. Conclusions: To summarize, this study proposes a novel method for estimating instantaneous phase differences. According to the findings from both the simulation and human-subject data, our approach was demonstrated to be effective. The method offers the following advantages: (1) improves the temporal resolution, (2) does not introduce a phase delay, (3) works with non-sinusoidal signals, (4) provides quantitative phase estimation without estimating the embedded frequency of breathing signals, and (5) works without calibrated measurements. The results demonstrate a higher temporal resolution of the phase difference estimation for the evaluation of thoracoabdominal asynchrony.
Physiological Responses to Different CO2 Levels in Poor Ventilation Room
(2015-01-01)
Chen, Ya-Chen
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Hsiao, Tzu-Chien
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資訊工程學系
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Department of Computer Science
According to ventilation of acceptable indoor air quality (IAQ), the air carbon dioxide concentration (C-CO2) and air temperature (T-a) increase with human in poor ventilation. The main source of CO2 pollution indoor is human respiration. This study simulates a poor ventilation condition and 10 volunteers participate with non-mask method to study the physiological responses in three C-CO2 levels. Facial temperature (T-f), saturation of percentage oxygen (SpO(2)), and electrocardiography (HR) were spontaneously acquired while subjects were inside an airtight room. Analytical results indicate SpO(2) decreased as C-CO2 increased. Those results further demonstrate a positive correlation between C-CO2/HR and C-CO2/T-f, implying that the central-chemoreflex can stimulate the respiratory system since SpO(2) variance and increased HR can promote pulmonary gas exchange. Notably, temperature difference in T-f and T-a increased under low C-CO2 and then reversed and stabilized inference the antagonistic pattern accelerated rapidly initially and decelerated finally stabilized. These findings also imply that the internal body responded to changes in the external environment rapidly, attempted to homeostasis, and reached equilibrium slowly. Variations of C-CO2 and T-a can be modeled by equations. Results of this study prove that IAQ affects physiological responses in the symbiotic relationship between the human body and surrounding environment.
Recognizing Thoracic Breathing by Ensemble Empirical Mode Decomposition
(2013-01-01)
Chen, Jin-Long
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Chen, Ya-Chen
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Hsiao, Tzu-Chien
;
資訊工程學系
;
Department of Computer Science
Recognizing breathing pattern is important in many fields of medicine. Ensemble empirical mode decomposition (an adaptive algorithm) was used to investigate breathing pattern, including thoracic breathing (TB) and abdominal breathing (AB). This study recognizes TB and AB by correlation coefficient and power proportion. Results indicate that the recognition accuracy of TB by correlation coefficient and power proportion are 85.2% and 93.3% respectively, and that of AB by correlation coefficient and power proportion are 54.3% and 56.2% respectively. The TB can be well defined and recognized in complex time variation. These results can be used as references to develop the real time breathing evaluation system in the future.
Towards estimation of respiratory muscle effort with respiratory inductance plethysmography signals and complementary ensemble empirical mode decomposition
(2018-07-01)
Chen, Ya-Chen
;
Hsiao, Tzu-Chien
;
分子醫學與生物工程研究所
;
資訊工程學系
;
生醫電子轉譯研究中心
Respiratory inductance plethysmography (RIP) sensor is an inexpensive, non-invasive, easy-to-use transducer for collecting respiratory movement data. Studies have reported that the RIP signal's amplitude and frequency can be used to discriminate respiratory diseases. However, with the conventional approach of RIP data analysis, respiratory muscle effort cannot be estimated. In this paper, the estimation of the respiratory muscle effort through RIP signal was proposed. A complementary ensemble empirical mode decomposition method was used, to extract hidden signals from the RIP signals based on the frequency bands of the activities of different respiratory muscles. To validate the proposed method, an experiment to collect subjects' RIP signal under thoracic breathing (TB) and abdominal breathing (AB) was conducted. The experimental results for both the TB and AB indicate that the proposed method can be used to loosely estimate the activities of thoracic muscles, abdominal muscles, and diaphragm.