• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.538-541
• /
• 2002

Dynamic analysis and compensation design for an asymmetrical half bridge do-dc converter are presented. A small-signal model is developed using the averaging method. Based on the proposed small-signal average model, the open loop transfer functions of the power stage were obtained and used for the compensation design. All theoretical predictions are validated by experiments on a prototype converter.

• Journal of Power Electronics
• /
• v.16 no.2
• /
• pp.532-541
• /
• 2016

A single-phase asymmetrical cascaded multilevel inverter is introduced with the goal of increasing power quality with the reduction of power in insulated-gate bipolar transistor (IGBT) switches. In the present work, the proposed inverter topology is analyzed and generalized with respect to different proposed algorithms for choosing different voltage source values. To prove the advantages of the proposed inverter, a case study involving a 17-level inverter is conducted. The simulation and experimental results with reduced THD are also presented and compared with the MATLAB/SIMULINK simulation results. Finally, the proposed topology is compared with different multilevel inverter topologies available in the literature in terms of the number of IGBT switches required with respect to the number of levels generated in the output of inverter topologies.

• The Journal of Churna Manual Medicine for Spine and Nerves
• /
• v.6 no.1
• /
• pp.11-17
• /
• 2011

A 28-year-old woman presented with postpartum pelvic pain. The patient complained severe pain and couldn't walk at all a week after natal. Computed tomography and plain radiography of the pelvis didn't reveal abnormal condition except asymmetrical alignment. Chuna treatment isn't usually applicable to the patient after natal. But we tried Chuna treatment to adjust the asymmetrical alignment of pelvis by half degree of strength. The pelvic pain improved considerably after 2 weeks treatment, so we report this case to emphasize the role of Chuna treatment in the management of postpartum pelvic pain.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.277-282
• /
• 1996

An asymmetrical cross-coupled compensator to improve the contouring performance is proposed. This is a refinement of the structure suggested by Koren. The position loop is closed with a proportional controller as in the uncoupled system. An additional input term proportional to the component of the contour error along the corresponding axis Is included. The controller gains are chosen to give an appropriate frequency response and an optimum range for the damping ratio. The effectiveness of the proposed controller is studied by means of digital simulations of the dynamics of the drives and the controller for 3 types of command trajectories; straight line contour, cornering contour, circular contour. Substantial improvement in contouring performance is obtained for a range of contouring conditions.

• Proceedings of the KIEE Conference
• /
• 1998.07f
• /
• pp.1899-1901
• /
• 1998

A five-level VSI(Voltage Source Inverter) is introduced as a SVC(Static Var Compensator) like a large scale power source. The problems in using SVC are that the power device can easily be destroyed by voltage unbalance and accurate reactive power control is difficult because of voltage variation. A asymmetrical PAM(Pulse Amplitude Modulation) switching pattern is proposed to solve this problem and analyze both fundamental component and harmonic current in the system. Through experimental results of 3.5 kVA experimental test system. It is confirmed that DC capacitor voltage can be controlled by asymmetrical PAM switching pattern control.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.825-826
• /
• 2006

This paper describes the effects of air gap eccentricity in induction machines. Asymmetric electro-magnetic force caused by the frictional worn bearing, rotor misalignment and unbalanced rotor etc. generates an asymmetrical operation, vibration and electro-magnetic noise. In this paper, we focus on investigating the asymmetrical operation considering of unbalanced magnetic force in squirrel-cage induction motor with 380 [V], 7.5 [kW], 4P, 1,768 [rpm]. The effects of the rotor eccentricity, magnetic force are investigated by finite element method (FEM) and experiment. The results can be useful for on-line monitoring of an induction motor.

• Lingua Humanitatis
• /
• v.5
• /
• pp.93-106
• /
• 2003

Professor Daihyun Chung has recently presented an intriguing view of Ban-mal(non-honorific expressions) in Korean. He criticizes uses of Ban-mal, on the grounds that they presuppose the existence of hierarchical structures in human beings. Professor Chung also advocates ″a relational theory of Ban-mal″ according to which ascriptions of 'n-mal' should be relativized to the speaker-hearer relationship. He employs this view in showing that uses of Ban-mal indeed presuppose the existence of hierarchical structures in human beings I claim that Professor Chung has not shown the credibility of his relational theory of Ban-mal, and that this very view leads to an unintended and undesirable consequence. Moreover, 1 show that even if we assume that this view is true for the sake of an argument, he is not able to show that uses of Ban-mal indeed presuppose the existence of hierarchical structures. All he can show is rather that uses of 'Ban-mal'(a meta-linguistic expression) presuppose the existence of hierarchical structures. Finally, 1 conclude that what really presupposes the existence of hierarchical structures is the asymmetrical uses of Ban-mal and honorific expressions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.64-66
• /
• 2007

Asymmetric rolling, where circumferential velocities of the upper and lower rolls differ, can be one method to change texture of magnesium alloy sheet by introducing shear deformation throughout the thickness of a sheet. In this study, the texture, microstructure and mechanical properties of AZ31 Mg sheets has been investigated during the symmetrical rolling procedure and the asymmetric rolling procedures of different roll speeds with different roll diameters. Texture of Mg alloy sheets were evaluated by using X-ray diffraction and ODFs were calculated using ADC method. The major texture of rolled specimens can be expressed by ND//(0001) fiber texture. The major fiber texture changed according to the rolling processes and such a slight difference of texture changes the formability of sheets. The mechanical properties were enhanced during asymmetrical rolling.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.3
• /
• pp.161-167
• /
• 1998

A problem of frequency in the field of low-frequencies such as high-rise apartment building or construction vibration are often found. In this study, damage reason of a 25 stories apartment building was searched on the basis of actual damage. To find the damage reason, structural design procedure were reviewed and low-frequency vibration test was conducted. The results indicate that the main damage reason is not by the low-frequency vibration but the asymmetrical plan of that building.

• IE interfaces
• /
• v.16 no.spc
• /
• pp.39-44
• /
• 2003

As one of many design variables, the role of dimension tolerances is to restrict the amount of size variation in a manufactured feature while ensuring functionality. In this study, a nonlinear integer model has been modeled to allocate the optimal tolerance to each individual feature at a minimum manufacturing cost. While a normal distribution determines statistically worst tolerances with its symmetrical property in many previous tolerance allocation studies, a asymmetrical distribution is more realistic because its mean is not always coincident with a process center. A nonlinear integer model is modeled to allocate the optimal tolerance to a feature based on a beta distribution at a minimum total cost. The total cost as a function of tolerances is defined by machining cost and quality loss. After the convexity of manufacturing cost is checked by the Hessian matrix, the model is solved by the Complex Method. Finally, a numerical example is presented demonstrating successful model implementation for a nonlinear design case.