The Association between Obesity and Asthma in Children-A Systemic Literature Review

Pei-Ching Liu,Bih-Shy,Gau 한국간호과학회 2009 한국간호과학회 학술대회 Vol.2009 No.10

Improve the clinical communication skills of nurses and nursing students with the "Scaffolding Theory”: A pilot study

Pei-Ching Lu,Shr-Han Shie,Chia-Lun Lee 한국간호과학회 2019 한국간호과학회 학술대회 Vol.2019 No.10

Real-time hybrid simulation of smart base-isolated raised floor systems for high-tech industry

Pei-Ching Chen,Shiau-Ching Hsu,You-Jin Zhong,Shiang-Jung Wang 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.1

Adopting sloped rolling-type isolation devices underneath a raised floor system has been proved as one of the most effective approaches to mitigate seismic responses of the protected equipment installed above. However, pounding against surrounding walls or other obstructions may occur if such a base-isolated raised floor system is subjected to long-period excitation, leading to adverse effects or even more severe damage. In this study, real-time hybrid simulation (RTHS) is adopted to assess the control performance of a smart base-isolated raised floor system as it is an efficient and cost-effective experimental method. It is composed of multiple sloped rolling-type isolation devices, a rigid steel platen, four magnetorheological (MR) dampers, and protected high-tech equipment. One of the MR dampers is physically tested in the laboratory while the remainders are numerically simulated. In order to consider the effect of input excitation characteristics on the isolation performance, the smart base-isolated raised floor system is assumed to be located at the roof of a building and the ground level. Four control algorithms are designed for the MR dampers including passive-on, switching, modified switching, and fuzzy logic control. Six artificial spectrum-compatible input excitations and three slope angles of the isolation devices are considered in the RTHS. Experimental results demonstrate that the incorporation of semi-active control into a base-isolated raised floor system is effective and feasible in practice for high-tech industry.

Robust stability analysis of real-time hybrid simulation considering system uncertainty and delay compensation

Pei-Ching Chen,Po-Chang Chen 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.6

Real-time hybrid simulation (RTHS) which combines physical experiment with numerical simulation is an advanced method to investigate dynamic responses of structures subjected to earthquake excitation. The desired displacement computed from the numerical substructure is applied to the experimental substructure by a servo-hydraulic actuator in real time. However, the magnitude decay and phase delay resulted from the dynamics of the servo-hydraulic system affect the accuracy and stability of a RTHS. In this study, a robust stability analysis procedure for a general single-degree-of-freedom structure is proposed which considers the uncertainty of servo-hydraulic system dynamics. For discussion purposes, the experimental substructure is a portion of the entire structure in terms of a ratio of stiffness, mass, and damping, respectively. The dynamics of the servo-hydraulic system is represented by a multiplicative uncertainty model which is based on a nominal system and a weight function. The nominal system can be obtained by conducting system identification prior to the RTHS. A first-order weight function formulation is proposed which needs to cover the worst possible uncertainty envelope over the frequency range of interest. Then, the Nyquist plot of the perturbed system is adopted to determine the robust stability margin of the RTHS. In addition, three common delay compensation methods are applied to the RTHS loop to investigate the effect of delay compensation on the robust stability. Numerical simulation and experimental validation results indicate that the proposed procedure is able to obtain a robust stability margin in terms of mass, damping, and stiffness ratio which provides a simple and conservative approach to assess the stability of a RTHS before it is conducted.

Advanced Imaging of Nanometer-Scale Recorded Bits on Super-Resolution Near-Field Optical Disk

Pei Lin Yang,Din Ping Tsai,Cheng Wei Lin,Chih Ching Hsu,Pei Hsin Chang,Tsung Sheng Kao,Wei Chih Lin 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.1

An advanced imaging technique is demonstrated for fast, non-destructive and high resolution characterizations for nanometer-scale recorded bits on a super-resolution near-field optical disk (super-RENS). For the first time, an array of individual 100 nm recorded marks is imaged and studied by using the conductive-atomic force microscopy (C-AFM) method. Discussions also include comparisons of 300 nm, 200 nm and 100 nm recorded marks on both a super-RENS disk and a commercial DVD disk, and the image results are evidence of the high carrier-to-noise ratio (CNR) value on the super-RENS disk, even though the mark size has been shrunk to less than the diffraction limit.

Numerical modelling of a shear-thickening fluid damper using optimal transit parameters

Pei-Ching Chen,Chung-Han Yu,Yohanes K. Surjanto,Shen-Kai Peng,Kuo-Chun Chang 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.30 No.5

The viscosity of a shear-thickening fluid damper (STFD) can increase dramatically when the STFD undergoes highrate of excitation. Therefore, accurate numerical modelling of the STFD has been considered difficult due to this distinct feature. This study aims to develop a numerical model to accurately simulate the response of the STFD. First, a STFD is designed, fabricated, and installed in the laboratory. Then, performance tests are conducted in which sine waves with nine frequencies at three amplitude levels are adopted as the displacement excitations to the STFD. A novel numerical model which contains two parameter sets of the discrete Bouc-Wen model as well as two parameters for transiting the two parameter sets. Therefore, a total number of eighteen parameters need to be identified in the damper model. The symbiotic organisms search is applied to optimize the parameters. Numerical simulation results demonstrate that the proposed STFD model with transit parameter sets outperforms the conventional discrete Bouc-Wen model. The proposed STFD model can be applied to analyses of structures in which STFDs are installed in the future.

Correlation of Aortic Valve Calcification Volume Using Cardiac-Gated Contrast-Enhanced CT with Aortic Stenosis Severity Using Echocardiographic Indices

Pei Ing Ngam,Ching Ching Ong,Edgar Lik Wui Tay,Jimmy Kim Fatt Hon,Chongri Liang,Lynette Li San Teo 아시아심장혈관영상의학회 2021 Cardiovascular Imaging Asia Vol.5 No.3

Objective: The aim of the study is to assess feasibility of using aortic valve calcification volume (AVCV) as a surrogate marker for aortic stenosis (AS) by studying the correlation between AVCV on contrast enhanced CT (CECT) and severity of AS using echocardiographic indices. Materials and Methods: Ninety-four patients with AS, who underwent CECT and echocardiography as part of pre-transcatheter aortic valve implantation assessment were analysed. AVC was quantified on CECT using methodology validated by Bischoff et al. Severity of AS was categorized by echocardiography indices [transaortic jet velocity, mean pressure gradient, aortic valve area (AVA) by continuity and planimetry equations, indexed AVA to body surface area and dimensionless index (DI)]. Results: Moderate to strong correlation was found between AVCV with transaortic jet velocity (rs=0.397, p<0.001), peak pressure gradient (rs=0.410, p<0.001) and mean pressure gradient (rs=0.381, p<0.001). There was statistically significant correlation between AVCV with indexed AVA (rs=-0.225, p<0.001) and DI (rs=-0.644 p<0.001) but not with AVA by continuity equation (rs=-0.024, p<0.826) and by planimetry (rs=-0.185, p<0.158). Although not statistically significant, patients with higher degree of AS were noted to have higher AVCV burden on CECT. Conclusion: Quantification of AVCV using CECT is a potential complementary marker for grading of AS severity. AVCV has additive value when there is discrepancy between clinical and echocardiography examinations or discordant echocardiographic indices due to variation in techniques of imaging and small body size in Asian population.

Performance-based optimization of LQR for active mass damper using symbiotic organisms search

Pei-Ching Chen,Bryan J. Sugiarto,Kai-Yi Chien 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.4

The linear-quadratic regulator (LQR) has been applied to structural vibration control for decades; however, selection of the weighting matrices of an LQR mostly depends on trial and error. In this study, a novel metaheuristic optimization method named as symbiotic organisms search (SOS) algorithm is applied to tuning LQR weighting matrices for active mass damper (AMD) control systems. A 10-story shear building with an active mass damper installed at the top is adopted as a benchmark for numerical simulation in order to realize the optimization performance considering three objective functions for mitigation of structural acceleration. Two common optimization methods including genetic algorithm (GA), and particle swarm optimization (PSO) are also applied to this benchmark for comparison purposes. Numerical simulation results indicate that SOS is superior to GA and PSO on searching the minimized solution of the three objective functions. Meanwhile, minimizing the square root of the sum of the squares of peak modal acceleration achieves the best control performance of structural acceleration among the three objective functions. In addition, force saturation is proposed and applied in the optimization process such that the control force level is close to the force capacity of AMD under specified earthquake intensity. Furthermore, the control performance of the optimized LQR is compared with that of the LQR designed by applying three common weighting selection methods when the 10-story building is subjected to various earthquake excitations. Simulation results demonstrate that the optimized LQR significantly outperforms the three LQRs on structural acceleration responses as expected and reduces story drift slightly better than the three LQRs. Finally, the performance-based optimized LQR is experimentally validated by conducting shake table testing in the laboratory. The experimental results and structural control performance are discussed and summarized thoroughly.

Servo control strategy for uni-axial shake tables using long short-term memory networks

Pei-Ching Chen,Kui-Xing Lai 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.32 No.6

Servo-motor driven uniaxial shake tables have been widely used for education and research purposes in earthquake engineering. These shake tables are mostly displacement-controlled by a digital proportional-integral-derivative (PID) controller; however, accurate reproduction of acceleration time histories is not guaranteed. In this study, a control strategy is proposed and verified for uniaxial shake tables driven by a servo-motor. This strategy incorporates a deep-learning algorithm named Long Short-Term Memory (LSTM) network into a displacement PID feedback controller. The LSTM controller is trained by using a large number of experimental data of a self-made servo-motor driven uniaxial shake table. After the training is completed, the LSTM controller is implemented for directly generating the command voltage for the servo motor to drive the shake table. Meanwhile, a displacement PID controller is tuned and implemented close to the LSTM controller to prevent the shake table from permanent drift. The control strategy is named the LSTM-PID control scheme. Experimental results demonstrate that the proposed LSTM-PID improves the acceleration tracking performance of the uniaxial shake table for both bare condition and loaded condition with a slender specimen.

Gastrodia elata Bl. Attenuated Learning Deficits Induced by Forced-Swimming Stress in the Inhibitory Avoidance Task and Morris Water Maze

Pei-Ju Chen,Keng-Chen Liang,Hui-Chen Lin,Ching-Liang Hsieh,Kuan-Pin Su,Mei-Chu Hung,Lee-Yan Sheen 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.6

This study adopted the forced-swimming paradigm to induce depressive symptoms in rats and evaluated the effects on learning and memory processing. Furthermore, the effects of the water extract of Gastrodia elata Bl., a well-known Chinese traditional medicine, on amnesia in rats subjected to the forced-swimming procedure were studied. Rats were subjected to the forced-swimming procedure, and the inhibitory avoidance task and Morris water maze were used to assess learning and memory performance. The acquisition of the two tasks was mostly impaired after the 15-minute forced-swimming procedure. Administration of the water extract of G. elata Bl. for 21 consecutive days at a dosage of 0.5 or 1.0 g/kg of body weight significantly improved retention in the inhibitory avoidance test, and the lower dose showed a better effect than the higher one and the antidepressant fluoxetine (18 mg/kg of body weight). In the Morris water maze, the lower dose of the water extract of G. elata Bl. significantly improved retention by shortening escape latency in the first test session and increasing the time in searching the target zone during the probe test. These findings suggest that water extracts of G. elata Bl. ameliorate the learning and memory deficits induced by forced swimming.