• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.31-33
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• 1989

In this paper, a short primary-short secondary single-sided LIM which is used as a driving source for automatic conveyor system, is selected as a analysis model. And with a method for analyzing eddy current distribution and thrust force which are produced according to the relative position of primary and secondary, FEM in which current vector potential is introduced is adopted. Also, analysis results are compared with experimental results, so propriety of this at study is proved.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.4 no.2
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• pp.1-6
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• 2008

Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation. The VHTR can produce hydrogen from heat and water by using a thermo-chemical process or from heat, water, and natural gas by steam reformer technology. A co-axial double-tube primary hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the VHTR. In this study, a preliminary design analysis for the primary HGD of the nuclear hydrogen system was carried out. These preliminary design activities include a determination of the size, a strength evaluation and an appropriate material selection. The determination of the size was undertaken based on various engineering concepts, such as a constant flow velocity model, a constant flow rate model, a constant hydraulic head model, and finally a heat balanced model.

• Journal of Communications and Networks
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• v.17 no.3
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• pp.265-266
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• 2015

In a recent paper [1], the authors investigated the maximum stable throughput region of a network composed of a rechargeable primary user and a secondary user plugged to a reliable power supply. The authors studied the cases of an infinite and a finite energy queue at the primary transmitter. However, the results of the finite case are incorrect. We show that under the proposed energy queue model (a decoupled M/D/1 queueing system with Bernoulli arrivals and the consumption of one energy packet per time slot), the energy queue capacity does not affect the stability region of the network.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.5
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• pp.453-461
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• 1990

In this paper, a short primary-short secondary single-sided linear induction motor which is used as the driving source for an automatic conveyor system, is selected as an analysis model. The finite element method in which the current vector potential is introduced is adopted to analyze the eddy current distribution and thrust force which are produced according to the relative position of the primary and the secondary. Also, the analysis results are compared with experimental ones, to show the propriety of this model.

• Proceedings of the KIEE Conference
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• summer
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• pp.797-799
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• 2004

The discontinuous primary linear synchronous motor is proposed as a driving source in the middle-distance transportation systems in factories and facilities. This paper describes the examination about the acceleration characteristics and a synchronizing method when the secondary mover overlaps with the primary from the inertia travel motion section in the whole of the re-acceleration part.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.155-156
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• 2015

This paper proposes a high efficiency wireless power transfer system with an asymmetric 4-coil resonator. It presents a theoretical analysis, an optimal design method, and experimental results. In the proposed asymmetric 4-coil system, the primary side consists of a source coil and two transmitter coils which are called intermediate coils, and in the secondary side, a load coil serves as a receiver coil. In the primary side, two intermediate coils boost the apparent coupling coefficient at around the operating frequency. Because of this double boosting effect, the system with an asymmetric 4-coil resonator has a higher efficiency than the conventional symmetric 4-coil system. The prototype operates at 90 kHz ofswitching frequency and has 200 mm of the power transmission distance between the primary side and the secondary side. An AC-DC overall system efficiency of 96.56% has been achieved at 3.3 kW of output power.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.4
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• pp.223-231
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• 2015

Enclosures are widely used to alleviate the contribution of machinery noise. It has been long concerned with the noise transmission through the access openings of the enclosures. In this study, we investigate active noise control technology for reduction of the transmission. A numerical model based on the acoustic boundary element method is first established. Using the numerical model, the acoustic transfer functions of the field points over the opening to the primary source at arbitrary locations are estimated. The feedforward control to minimize the acoustic power through the opening is then numerically implemented. The controller drives the secondary source to destructively interfere the noise transmission through the opening. Finally, a parametric study is conducted to evaluate the effects of the location and the number of the microphones on the control performance. Furthermore, the effects of the location of the secondary source on the performance of active noise control are investigated. It is followed that the control system implemented in this study leads to a significant reduction of about 31.5 dB in the sound power through the opening using only one secondary source located at the optimized position.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.562-573
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• 2008

Concentrations of volatile organic compounds (VOCs) measured from the local industrial sources in Wanju industrial complex during June $2007{\sim}January$ 2008. The samples were collected from the primary sources (6 emission points) in 4 major factories in Wanju industrial complex as well as two general sources in Wanju County to elucidate the abundances of speciated VOCs and their spacial and temporal distributions depending on source bases. Industrial sources are as follows; fabricated metal manufacture, motor vehicle manufacture, rubber and plastic manufacture, and chemical manufacture factories. Two general source samples were collected from gasoline gas station and dry cleaning shop in urban area. In order to understand the near source influence at receptor, samples from the two receptor sites (one is at center of the industrial complex and the other site is at distance residential area downwind from the center) were collected with sample canister, and analyzed by using GC/MSD. The concentrations from different sources were compared and discussed. The mass contributions of the speciated VOCs to total VOCs measured from industrial sources and ambient ai r at two receptors were presented and discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.796-802
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• 2013

In this study, we investigates active control technology to reduce the noise transmitted to the outside through the opening of enclosures. A numerical model based on acoustic boundary element method is first established. Using the numerical model, the acoustic transfer functions of the field points over the opening to the primary source at arbitrary locations are estimated. The feedforward control to minimize the acoustic power through the opening is then numerically implemented. The controller generates the secondary source to destructively interfere the noise transmission through the opening. Finally, a parametric study is conducted to evaluate the effects of the location and the number of the microphones on the control performance. Furthermore, the effects of the location of the secondary source on the performance of active noise control are investigated. It is followed that the control system implemented in this study leads to a significant reduction of about 35dB in sound power through the open using only on secondary source located at the optimized position.

• Korean Journal of Child Studies
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• v.31 no.4
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• pp.179-197
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• 2010

The present study investigated how mothers with infants and toddlers obtain information about parenting and examined the nature of maternal parenting knowledge in order to evaluate the quality of the information. The mothers' age and educational level were included in the analysis as a influential factor on parenting knowledge. Four hundred and twenty-nine mothers with infants and toddlers completed the questionnaires issued regarding the source and content of parenting information and parenting knowledge. The results indicated that the mothers with only one child preferred to utilize their friends and relatives as their primary source of information and the mothers with more than one child acquired parenting information from their own previous experience. Second, the subjects were most interested in acquiring information related to physical development and medical problems. Third, the main effects of all independent variables were found. In addition, the interactional effects between the educational level and source of parenting information for the mother with only one child and the interactional effects between age and source of parenting information for the mother with more than one child were determined as a result of this study. These results indicate that there are some high-risk groups when it comes to the acquisition of parenting knowledge and we suggest providing valid and reliable information to these most vulnerable groups.