• PNF and Movement
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• v.14 no.2
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• pp.131-137
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• 2016

Purpose: The purpose of this study was to compare muscle activities in the frontal plane and scapular plane of the middle fiber and lower fiber of the trapezius muscle at different shoulder abduction angles. Methods: Twenty male and female students in their 20s participated in this study. Each subject maintained shoulder abduction at $75^{\circ}$, $90^{\circ}$, $125^{\circ}$, and $160^{\circ}$ in a standing position and repeated motions three times each in the frontal plane and the scapular plane. While maintaining the motions for 10 seconds in each posture, surface electromyography (EMG) was used to measure muscle activity of the middle fiber and lower fiber of the trapezius muscle. The collected EMG data were normalized using maximal voluntary isometric contraction (MVIC). Differences in muscle activity of the middle fiber and lower fiber of the trapezius muscles according to the angles at each plane were statistically processed using repeated measured analysis of variance, and an independent t-test was used to examine the differences between the two planes at each angle. Results: Muscle activity of the middle and lower trapezius during shoulder abduction in the frontal plane and scapular plane significantly increased as the angles increased (p<.05). However, muscle activity of the middle trapezius was significantly lower in the scapular plane than in the frontal plane for all shoulder abduction angles (p<.05). Conclusion: The results of this study suggest that during shoulder abduction, angles should be different according to the goals, and for training during an acute phase or early phase for functional recovery, it is more efficient to perform the training in the scapular plane than in the frontal plane.

• Journal of computational fluids engineering
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• v.13 no.3
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• pp.44-50
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• 2008

The present study is carried out in order to investigate the effect of the periodic acceleration in the stenosed and bifurcated blood vessels. The blood flow and wall shear stress are changed under body movement or acceleration variation. Numerical studies are performed for various periodic acceleration phase angles, bifurcation angles and section area ratios of inlet and outlet. It is found that blood flow and wall shear stress are changed about ${\pm}20%$ and ${\pm}24%$ as acceleration phase angle variation with the same periodic frequency. also wall shear stress and blood flow rate are decreased as bifurcation angle increased.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1682-1691
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• 2015

In this paper, a real time implementation of selective harmonic elimination pulse width modulation (SHEPWM) using Real Coded Genetic Algorithm (RGA), Particle Swarm Optimization technique (PSO) and a new technique known as Linearization Method (LM) for Single Phase Matrix Converter (SPMC) is designed and discussed. In the proposed technique, the switching frequency is fixed and the optimum switching angles are obtained using simple mathematical calculations. A MATLAB simulation was carried out, and FFT analysis of the simulated output voltage waveform confirms the effectiveness of the proposed method. An experimental setup was also developed, and the switching angles and firing pulses are generated using Field Programmable Gate Array (FPGA) processor. The proposed method proves that it is much applicable in the industrial applications by virtue of its suitability in real time applications.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.06a
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• pp.718-721
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• 1998

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.80-80
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• 2006

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.571-580
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• 2003

Tomography has been investigated to observe bubble behaviors in two-phase flows. A bubbly flow and an annular flow have been reconstructed by tomography methods such as an algebraic reconstruction technique (ART) and a multiplicative algebraic reconstruction technique (MART) . Computer synthesized phantom fields have been used to calculate asymmetric density distributions for limited cases of 3, 5, and 7 projection angles. As a result of comparison of two tomography methods, the MART method has shown a significant improvement in the reconstruction accuracy for analysis of the two-phase flows.

• Journal of Mechanical Science and Technology
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• v.17 no.8
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• pp.1234-1245
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• 2003

An experimental study was carried out to investigate the reduced frequency effect on the near-wake of an elliptic airfoil oscillating in pitch. The airfoil was sinusoidally pitched around the center of the chord between -5$^{\circ}$and ＋25$^{\circ}$angles of attack at an airspeed of 3.4 m/s. The chord Reynolds number and reduced frequencies were 3.3 ${\times}$10$^4$, and 0.1, 0.7, respectively Phase-averaged axial velocity and turbulent intensity profiles are presented to show the reduced frequency effects on the near-wake behind the airfoil oscillating In pitch. Axial velocity defects in the near-wake region have a tendency to increase in response to a reduced frequency during pitch up motion, whereas it tends to decrease during pitch down motion at a positive angle of attack. Turbulent intensity at positive angles of attack during the pitch up motion decreased in response to a reduced frequency, whereas turbulent intensity during the pitch down motion varies considerably with downstream stations. Although the true instantaneous angle of attack compensated for a phase-lag is large, the wake thickness of an oscillating airfoil is not always large because of laminar or turbulent separation.

• Korean Journal of Optics and Photonics
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• v.3 no.2
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• pp.105-110
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• 1992

In order to measure fine rotation angles by magneto-optic effects of magneto-optical recording thin films, a polarization modulation method is used. In the experiment, the polarization of laser (He-Ne laser) beam is modulated by a Faraday rotator and the amplified modulated signals are selectively detected by phase sensitive detector. The magnetic Kerr rotation and Faraday rotation hysteresis loops are investigated by this method for thermally evaporated amorphous TbFeCo thin films and RF sputtered garnet thin films. Rotation angles about $0.25^{\circ}$ are measured easily from TaFeCo thin films. In the case of longitudinal Kerr rotation, very small rotation angle of $2.5\times10^{-3^\circ}$ is measured with good accuracy of the measurement (about $1\times10^{-3^\circ}$). And it is found that each thin films have the hysteresis curves of high coercivity and good squareness.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1528-1538
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• 2018

In this paper, configuration of $1-{\phi}$ seven-level boost DC-link cascade based reversing voltage multilevel inverter (BDCLCRV MLI) is proposed for uninterrupted power supply (UPS) applications. It consists of three level boost converter, level generation unit and full bridge circuit for polarity generation. When compared with conventional boost cascaded H-bridge MLI configurations, the proposed system results in reduction of DC sources, reduced power switches and gate drive requirements. Inverter switching is accomplished by providing appropriate switching angles that is generated by any optimization switching angle techniques. Here, round modulation control (RMC) method is taken as the optimization method and switching angles are derived and the same is compared with various switching angles methods i.e., equal-phase (EP) method, and half-equal-phase (HEP) method which results in improved quality of obtained AC power with lowest total harmonic distortion (THD). Reduction in DC sources and switch count makes the system more cost effective. A simulation and prototype model of $1-{\phi}$ seven-level BDCLCRV MLI system is developed and its performance is analyzed for various operating conditions.

• Journal of IKEEE
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• v.28 no.3
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• pp.432-439
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• 2024

This paper introduces an enhanced Selective Harmonic Elimination (SHE) technique of a single-phase Cascaded H-Bridge (CHB) Multilevel Inverter (MLI) for improving the reliability and power quality of a second life battery energy storage system (ESS). The technique involves solving non-linear transcendental equations derived from Fourier series offline to determine the optimal switching angles for the proposed SHE-PWM implementation. These angles are then applied in real-time via a Look-Up Table (LUT). The Levenberg-Marquardt algorithm, an iterative method, is employed in MATLAB to solve the equations and obtain the switching angles. The effectiveness of the proposed method is validated using PLECS simulation software and is compared with other conventional PWM techniques for MLIs.