• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.419-424
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• 2002

주방연소기의 사용 부주의로 인한 화재는 일반주택 및 다량의 열원을 사용하는 음식점 등에서 발생가능성이 가장 높다. 한편, 화재발생으로 인한 사망자의 80％는 연소가스에 의한 질식으로 사망하게 된다. 주방에 설치된 연소기 상부에는 일반적으로 배열, 제습 및 그리스제거 목적으로 주방후드를 설치되고 있으나 화재를 대비한 복합기능설비로 고안되어 있지 않다.(중략)

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.71-72
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• 2012

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.163-175
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• 2017

In land seismic exploration, irregular surface topography and weathering layer in near surface distorts the reflected signals of data. Therefore, typical land seismic data should be compensated for this distortion by static correction. To perform the static correction, near-surface velocity is required, which can be obtained by seismic refraction survey. However, land seismic data is often acquired in a limited form of geometry depending on the equipment availability, accessibility condition, and permission for the survey site. In this situation, refraction analysis should be performed using reflection data because it is impossible to acquire refraction-oriented data due to limited source and receiver geometry. In this study, we aimed to analyze the reliability of the results obtained by refraction traveltime tomography when using reflection data with a limited number of sources and receivers from irregular surface topography. By comparing the inversion result from irregular topography with that from flat surface, we found that the surface topography affects the reliability of the inversion results to some degree. We also found that the number of sources has little effect on the inversion results unless the number of sources are very small. On the other hand, we observed that velocity distortion occurred in the overlapped part of receiver arrays when using a limited number of receivers, and therefore suggested the size of the least overlapping ratio to avoid the velocity distortion. Finally, we performed numerical tests for the model which simulates the surface topography and acquisition geometry of the survey region and verified the reliability analysis of inversion results. We identified reliable areas and suspicious area of the inverted velocity model by applying the analysis results to field data.

• Economic and Environmental Geology
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• v.21 no.1
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• pp.107-113
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• 1988

We present a precedure for interpreting dipole-dipole apparent resistivity data. The procedure is constructed by combining a forward two-dimensional finite element modeling and an inverse technique with Householder's transformation. In the interpretation, subsurface structure is divided into some blocks with constant resistivities. Our inversion technique is tested on synthetic and field data. We found that geologic constraint is required for successful interpretation.

• Journal of the KSME
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• v.30 no.2
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• pp.180-187
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• 1990

세라믹 복합재료의 크립 파괴거동의 근원이 되는 크립거동에 대한 해석은 현재까지 제시되어 있 는 것이 거의 전무하여, 세라믹 복합재료의 고온신뢰도는 실험에 의존되어 많은 시간과 노력이 소요된다. 여기서는 해석방법으로 advanced shear-lag 모델을 기본으로 세라믹 복합재료 특성을 고려하여 모델링 해석을 제시하였다. 여러 영향 인자들-보강섬유 형상비, 보강섬유 끝단의 간격, 계면에서의 미끄름계수, 단위 모델안의 보강섬유 배열이 크립거동에 미치는 효과에 대해 인자 변화효과(parametric study)를 관찰하여 실험에 의해 얻은 SiCw/A1$_{2}$O$_{3}$의 크립 결 과와 비교하였다. 모델링 해석을 통해 얻은 특정범위 내의 결과는 실험결과를 수용할 수 있으 므로 이 해석방법을 세라믹 복합재료 크립거동의 한방법으로 이용할 수 있으리라 사료된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1740-1746
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• 1997

In this paper, a waveguide-fed slot-coupled microstrip antenna is proposed as enhanced feeding structure of microstrip antenna and an analysis is presented. The presence of dielectric substrate between a stripand a slot is explicitly taken into account in this analysis. The evaluation of the antenna characteristics is carried out using the method of mements and the spectral domain approach in terms of the electric current distribution on the strip and the magnetic current distribution on the slot. From the results, we can conclude that the proposed structure is adequate for array antennas, due to ease of mass porduction and enhanced anteena performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1223-1232
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• 2008

In this paper, an analytic method is proposed to extract the reference slot admittance required for the design of a non-resonant waveguide edge slot array. A slot and two neighboring transmission line sections of the numerous alternately inclined slots with the identical inclination angle are modelled as a uniform lossy transmission line, and thus, the total ABCD matrix is easily calculated and compared with the simulated or measured one. From this procedure, the complex characteristic impedance and the complex propagation constant of the lossy transmission line are calculated and the normalized slot admittance is analytically obtained. In order to validate the proposed method, the admittance value of a reference slotted waveguide fabricated for designing the X-band edge slot array is extracted and it is compared with the one obtained by the other conventional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.999-1004
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• 2011

In this paper, calculation method of mutual inductance for two circular coils which are widely used in wireless power transfer system and analysis results using the method are proposed. Two circular coils are arranged in a perpendicular way. For calculation of the mutual inductance, an Rx coil placed perpendicularly with the other coil is uniformly subdivided into many unit cells and both magnetic flux density linked with the Rx coil at each unit cell and the total magnetic flux density of the Rx coil are obtained. Two circular coils are considered as a filamentary coil and uniform current density on each coil is assumed. For verification, helical and spiral coils are fabricated. As a result of measurement in 50 cm to 100 cm distance, theoretical mutual inductance is almost agreed with measured one.

• Journal of Energy Engineering
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• v.29 no.3
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• pp.7-17
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• 2020

Heat recovery steam generator(HRSG) generate steam using the high-temperature exhaust energy of gas turbines. Structures of HRSG are damaged by flow induced vibration of flue gas in some cases. In order to evaluate fatigue life to predict damage to a structure, a vibration analysis caused from flue gas should be used to derive the Power Spectral Density(PSD). However, it is very difficult to experimentally derive the vibrations generated by the exhaust gas form of gas turbines, which is very fast and complex. It was able to establish a way to identify vibration characteristics depending on the location of the structure by using high computing resources, large eddy simulation (LES). Random vibration analysis through these vibration characteristics(PSD) can evaluate the fatigue life of a structure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.2
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• pp.119-126
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• 2016

In this study we investigated the effects of symmetrically arranged heat sources on the heat release performances of extruded-type heat sinks through experiments and thermal fluid simulations. Also, based on the results we suggested a high-efficiency and cost-effective heat sink for a solar inverter cooling system. In this parametric study, the temperatures between heaters on the base plate and the heat release rates were investigated with respect to the arrangements of heat sources and amounts of heat input. Based on the results we believe that the use of both sides of the heat sink is the preferred method for releasing the heat from the heat source to the ambient environment rather than the use of a single side of the heat sink. Also from the results, it is believed that the symmetric arrangement of the heat sources is recommended to achieve a higher rate of heat transfer. From the results of the thermal fluid simulation, it was possible to confirm the qualitative agreement with the experimental results. Finally, quantitative comparison with respect to mass flow rates, heat inputs, and arrangements of the heat source was also performed.