• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.909-913
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• 1998

Transient and static characteristics of HVDC inverter can be analyzed with various simulation tools. For the optimal filter design, various performance criteria are proposed. In this paper, performance index is calculated based on proposed per phase equivalent circuit. Voltage and harmonic and filter power loss are selected as criteria. Optimization procedure is performed to find optimal passive filter parameters. Dynamic characteristics is also analyzed with proposed equivalent circuit.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.197-203
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• 2001

In this paper, numerical analyses were undertaken to calculate the static and dynamic performances of step-pocket, inward pumping spiral grooved, outward pumping spiral grooved and herringbone grooved bearings. For each bearing, optimal values for various design parameters were obtained to maximize the load capacity and the stiffness and bearing performances were calculated. The optimized performances of these bearings were compared to conclude that the performance of step-pocket bearing is better than the other bearings.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.5
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• pp.531-539
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• 1991

We develop an analytical model of the static and the dynamic characteristics of amorphous silicon thin film transistors (a-Si TFTs) in order to incorporate into a widely used circuit simulator such as SPICE. The critical parameters considered in our analytical model of a-Si TFT are the power factor (XN) of saturation source-drain current and the effective channel length (L') at saturation region. The power factor, XN must not always obey so-called

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.269-276
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• 2001

Tubular structures are widely used for offshore platforms and truss type structures. In this paper, nonlinear finite element analysis is used to assess the static strength of stiffened tubular T-joints subjected to compressive brace loading. This joints was modelled with and without internal ring stiffener According to variation of ring geometries, the effect of ring stiffener for T-joints are investigated. Internal ring stiffener is found to be efficient improving ultimate strength of tubular joints. Relations of ring thickness and axial strength are observed considering geometric parameters of ring stiffeners.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.5
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• pp.355-360
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• 1991

A transmission-line discontinuities are analyzed by Finite Element Method. We use quasi-static approxmation to determine the circuit parameters of discontinuities. Delta formulation is introduced so that the cancellation error of potential calculation is reduced. To verify this method, capacitance of coaxial cable with discontinuous and coupling capacitances are calculated by modal expansion. This approach can be used for arbitrary discontinuous conducting patterns of microwave devices.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.664-669
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• 1991

In order to improve the reliability and the stability of static power conversion system, further to optimize the operational characteristics of the system, it is very important to investigate the effects (output and switching component characteristics) of each parameters in the system. Therefore this paper particualrly deals with the characteristics of a novel ZVS multi-resonant conversion system to duty cycle, resonant capacitance, resonant inductance, and output capacitance. The results show that resonant inductance and output capacitance are dominat factors in the system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1995.10b
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• pp.249-257
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• 1995

In this paper, we demeonstrate that neural networks can be used effectively for the control of nonlinear dynamical system. To adaptively control a plant, there are two distinct approach. these are direct control and indirect control. Both direct and Indirect adaptive control are trained using static back propagation. In indirect, using the resulting identification model, which contains neural networks and linear dynamical elements as subsystems, the parameters of the controller are adjusted.

• Journal of Aerospace System Engineering
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• v.5 no.2
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• pp.1-7
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• 2011

On this study, applicable aircraft pitot-static system airworthiness requirements and flight test techniques for PEC(Position Error Correction) to KAS Part 23 airworthiness standards are introduced. Also, pros and cons, applicable test conditions, test procedures and required test parameters of each flight test techniques are reviewed on this study.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.82-90
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• 2007

In order to analyse the strength problems for an unsaturated soil, it is required to examine closely the characteristics of the parameters of shear strength which was changed with the metric suction and void ratio. To this ends, a triaxial compression test was conducted on the three samples-granular soil, cohesive soil and silty soil. The specimen was made by pressing the static pressure on the mold filled soil and was controled the void ratio with the different compaction ratio. And the test was performed by using the modified apparatus of the triaxial compression tester. The range of matric suction was 0-90 kPa.The measured results for the deviator stress and parameters of shear strength were analysed with the void ratio and the compaction ratio, and they were examined closely the characteristics of the strength for an unsaturated soil.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.398-398
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• 2016

A triboelectric generator uses the principles of static electrification and electrostatic induction to convert mechanical energy into useful electrical energy. In this work we study a single degree of freedom (SDOF) vibration type triboelectric generator that is initiated by a vibrating source at its base. The system is modeled in Abaqus and the design parameters are systematically explored by their effect on the output. The relationships between the parameters: input force, input frequency, mass, spring stiffness and gap between the plates, are analyzed. Finally, based on initial experiments, and simulation results, a design methodology is formulated. The methodology will provide guidance for application specific design of reliable and effective vibration type triboelectric generators.