• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.211-219
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• 2018

This paper designs a nonlinear PI-type controller for the robust control of a boost DC-DC converter using a particle swarm optimization (PSO) algorithm. Based on the common knowledge that the transient responses can be improved if the P and I gains increase when the transient error is big, a nonlinear PI-type control design method is developed. A design procedure to autotune the nonlinear P and I gains is given based on a PSO algorithm. The proposed nonlinear PI-type controller is implemented in real time on a Texas Instruments TMS320F28335 floating-point DSP. Simulation and experimental results are given to demonstrate the effectiveness and practicality of the proposed method.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.3
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• pp.257-265
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• 2014

This paper proposes a simple compensation method for switches of the unclamped voltage in the three-level NPC inverter. Voltages of inner-switches can be unclamped in the three-level NPC (neutral point clamped) inverter. It can cause the problem of the switch fault accident. By adding a capacitor, switches of the unclamped voltage can be clamped. Through the analysis of the circuit, the reason behind switches being unclamped was verified which leads to the solution method that designs a compensation capacitor. The proposed method was validated through the simulation and experimental results.

• Journal of Power Electronics
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• v.14 no.4
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• pp.678-686
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• 2014

A novel auxiliary resonant commutated pole (ARCP) link for three-phase PWM voltage-fed converter is presented. The ARCP link consists of two auxiliary switches, one resonant inductance, and six diodes, which is simpler than the conventional ARCP designs. Based on the phase and amplitude control, the proposed converter can take a minimum switching times PWM method, which results in reduced losses and a simplified control. In addition, the zero-voltage resonance modes are analyzed. Finally, simulation and experimental results show that the system can realize zero-voltage switching with a unity power factor.

• Journal of Power Electronics
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• v.13 no.3
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• pp.437-446
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• 2013

This paper proposes a design scheme for an LCL-filter used for the three-parallel operation of the power converters in high-capacity wind turbines. The designs of the power devices and grid connected filter are difficult due to the high level voltages and currents in huge-capacity wind turbines. To solve these problem, this paper presents three-parallel operation and LCL-filter design techniques optimized by parallel operation. Furthermore, the design of an inverter side inductance of the LCL-filter is discussed in detail considering the switching modulation method. Simulation and experimental results demonstrate the validity of the designed filter and wind turbines.

• Genomics & Informatics
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• v.13 no.2
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• pp.40-44
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• 2015

DNA microarray and next-generation sequencing provide data that can be used for the genetic analysis of multiple quantitative traits such as gene expression levels, transcription factor binding profiles, and epigenetic signatures. In particular, chromatin opening is tightly coupled with gene transcription. To understand how these two processes are genetically regulated and associated with each other, we examined the changes of chromatin accessibility and gene expression in response to genetic variation by means of quantitative trait loci mapping. Regulatory patterns commonly observed in yeast and human across different technical platforms and experimental designs suggest a higher genetic complexity of transcription regulation in contrast to a more robust genetic architecture of chromatin regulation.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.80-85
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• 2006

HSS (high strength steel) is widely applied to reduce the weight but improve the strength in automobiles. This research has been peformed to secure a methodology to accurately predict the springback of HSS for successful tool and process designs in sheet stamping operations. We first peformed U-draw bending test to evaluate the springback characteristic. We then evaluated forming and springback processes using the 1-row model of the finite element method. Based on the peformance measure and parameters selected, extensive analyses of the factor effects on the springback have been made using experimental design concepts. We specifically selected Taguchi's orthogonal array, $L_{18}(2^1{\times}3^7)$, and the optimal level combination of the factors have been drawn from the analysis.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.249-256
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• 2009

The cooling technology of power conversion semiconductors in the propulsion system for the HEMU(High Electrical Multi Unit) are applied in water cooling method and phase change method such as the immersed type and the heat pipe type. This research designs and manufactures the water cooling system that could cool about heat load Q=2kW and performance tests to apply it by an electric power conversion semiconductors(IGBT) cooling technology. Experimental condition made change of a flow rate, an air velocity and a heat load to confirm operation characteristics of water cooling device, and when is heat load 2kW, air velocity 20 m/s, and water flow rate 7kg/s, it is about $80^{\circ}C$ to temperature of cooling plate.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.295-302
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• 2021

As glucocorticoids are well-known as important regulators of stress and the immune system, their function and clinical use have elicited substantial interest in the field of reproduction. In particular, the effect of glucocorticoid therapy on endometrial receptivity during assisted reproduction, including in vitro fertilization (IVF) cycles, has led to a great deal of interest and controversy. However, previous studies have not been able to provide consistent and reliable evidence due to their small, non-controlled designs and use of different criteria. Considering the potential risk of exposure to glucocorticoids for mothers and fetuses in early pregnancy, the use of glucocorticoids in IVF cycles should be carefully evaluated, including the balance between risk and benefit. To date, there is no conclusive evidence that the use of glucocorticoids improves the pregnancy rate in IVF cycles with unselected subjects, and a further investigation should be considered with a proper study design.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.611-615
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• 1994

In this paper, the sensitivity, linearity and temperature drift characteristics of various capacitive force sensors are evaluated and compared using new experimental methods. In particular, two designs were employed to reduce temperature drift. Both types of sensor use high-sensitivity Al coated PET film, and their externals are miniaturized. The first has a layered design consisting of two dielectric substances with different temperature characteristics. The prototype of this design had a temperature drift of only 0.1% of the sensor's capacity in the 20-80.deg. C range. The second type uses both a dummy sensor ind an active sensor with the same characteristics. The temperature drift of the prototype was one-fifth the temperature drift of a single sensor.

• Advances in Computational Design
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• v.8 no.1
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• pp.61-76
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• 2023

Fiber reinforced polymer (FRP) columns are increasingly being used in various engineering fields due to its high strength to weight ratio and corrosion resistance. Being a thin-walled structure, their designs are often governed by buckling.Buckling strength depends on state of stress of elements which is greatly influence by stacking sequence and various inaccuracies such as geometric imperfections and imperfections due to eccentricity of compressive load and non-uniform boundary conditions. In the present work, influence of load eccentricity on buckling strength of FRP column has been investigated by conducting parametric study. Numerical analyses were carried out by using finite element software ABAQUS. The finite element (FE) model was validated using experimental results from the literature, which demonstrated good agreement in terms of failure loads and deformed shapes.The influence of load eccentricity on buckling behavior is discussed with the help of developed graphs.