• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.880-885
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• 2017

Radiation from a cavity-backed circular aperture surrounded by concentric corrugations is studied. An electromagnetic boundary-value problem of the cavity-backed circular aperture surrounded by concentric corrugations is solved by using the Green's function, Hankel transform, and mode matching method. The radiated fields are computed in terms of corrugation geometry to illustrate radiation behaviors and measured to validate our computation. The effects of the corrugation geometries on the radiation are discussed.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.315-316
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• 2016

This paper proposes an enhanced distributed generation (DG) unit with an adaptive virtual impedance control approachin order to address the inaccurate reactive power sharing problems. The proposed method can adaptively regulate the DG unit thanks to the equivalent impedance, andthe effect of the mismatch in feeder impedance is compensatedto share the reactive power accurately.The proposed control strategy can be implemented directly without any requirement of pre-knowledge of the feeder impedances. Simulations are performed to validate the effectiveness of the proposed control approach.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.397-402
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• 2002

Six Sigma is one of the most active subjects in quality management. This study deals with some existing weaknesses that may arise in implementing Six Sigma in real world situations. The main weaknesses discussed here include the lack of understanding of cultural aspects on the nations and industries, the poor linkage between quality, finance and accounting from the bottom line point of view, and the difficult development process of metrics for all improvement results to validate the effect of Six Sigma. Finally, the key success characteristics for a good Six Sigma project are presented.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.519-524
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• 2009

This work presents a simple technique to determine the Poisson's ratio of homogeneous solid material using a pair of low cost PVDF ultrasonic transducers. It is based on transducer's property of generating longitudinal and transversal waves depending on the excitation frequency. Mechanical tests were conducted to validate the proposed method, resulting in a good agreement between ultrasonic and mechanical techniques.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.684-686
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• 2004

This paper is concerned with the DC motor speed control using distributed control system. We design CAN nodes which can transmit control and monitoring data through CAN bus and apply these to distributed networked control system. The results of the experiment validate effectiveness of our distributed networked control system.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.224-227
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• 2001

Adaptive analysis of multilayered composite and sandwich plates is carried out. The adaptive analysis is based on a finite element error form, which measures the difference between the through-the-thickness distribution of finite element displacement and the actual displacement. The region where the error-measure exceeds the prescribed admitted error value, the finite element mesh locally refined in the thickness direction using the mesh superposition technique. Several numerical tests are conducted to validate the effectiveness of the current approach for adaptive analysis of laminated plates.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.58-76
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• 2000

An analytical solution method capable of determining the geometric configuration and developed tensile forces of mooring lines associated with fixed plate/pile or drag anchors is presented. The solution method, satisfying complete equilibrium conditions, is capable of analyzing multi-segmented mooring lines that can consist of either chains, cables, or wires embedded in layered seafloor soils. Centrifuge model tests and full -scale field tests were used to calibrate and validate the analytical solution.

• Journal of electromagnetic engineering and science
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• v.4 no.3
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• pp.102-106
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• 2004

A novel Genetic Algorithm(GA)-based method is suggested to transform a coupling matrix to another, without the procedure of Matrix Rotation. This can remove tedious work like pivoting and deciding rotation angles needed for each of the iterations. The error function for the GA is simply formed and used as part of error minimization for obtaining the solution. An 8th order dual-mode elliptic integral function response filter is taken as an example to validate the present method.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.104-109
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• 1997

A robust controller design to corrdinate a robot manipulator under unknown system parameters and bounded disturbance inputs is presented in this paper. Generally, robust controllers require high input torque so that they may face input saturation in actual application due to the power limitation of the actuator. To solve this problem, an improved robust controller with saturated input torque using a fuzzy logic control is proposed. Numerical examples are shown to validate the proposed controller using two degree-of-freedom planar arm.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.359-365
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• 1998

A global optimization method known as the Shuffled Complex Evolution method from the University of Arizona(SCE-UA) was used for calibrating a Tank model. The model was calibrated with error-free synthetic data, and the SCE-UA method was found to effectively search optimal parameters. Historical data from an agricultural watershed was used to calibrate and validate the model parameters. The simulated results were in good agreement with the observed.