• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.66-71
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• 2003

Electronic equipments made from integrated circuits and small-sized semiconductors is protected by surge protective devices(SPDs) such as ZnO varistors, Zener diode and gas discharge tube from lightning overvoltages. However the clamping voltage of SPDs is greatly influenced by the method of installing the SPDs. In this paper, the protective effects of SPDs according to types of system groundings were experimentally investigated. The separate grounding is a particularly undesirable way to install SPDs. The effectiveness of the common grounding point for ZnO varistors is more pronounced than that for gas discharge tubes. The common grounding at the terminal of SPDs is recommended as a best method of installing SPDs.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.76-80
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• 1997

Acoustic resonance characteristics were analyzed and their effect on the refrigerating capability were experimentally verified on a fabricated Hofler-type thermoacoustic refrigerating system. Factors governing the overall resonance are the resonator composed of a cavity and two pipes, the loudspeaker driving the resonator, and rear side impedance characteristics of speaker housing. All these are coupled with electric constants of the speaker to exhibit electric resonance. Also the 'wall-effect' within the resonator causes attenuation to reduce the sharpness of the resonance. Analysis and experiments showed housing and the wall-effect of the resonator reduce the sharpness of resonance. Maintaining the accuracy of the resonance is, therefore, very important for efficient refrigeration.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.63-74
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• 2006

During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the full-scaled field test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM. From the full-scaled test in field, the use of in-situ CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the ground surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was the smaller than the other cases, and the absolute value was almost zero. Judging from the full-scaled field test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing the failure of the underground pipes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.4
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• pp.81-90
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• 2020

A textile and capillary tube composite panel(TCP) was developed to simultaneously retrofit the seismic performance and the energy efficiency (e.g. heating or insulation performance) of existing unreinforced masonry (URM) buildings. TCP is a light-weight mortar panel in which carbon textile reinforcements and capillary tubes are embedded. Textile reinforcements plays a role of seismic retrofit and capillary tubes that hot water circulates contribute to the energy retrofit. In this paper, the static cyclic loading tests were performed on the masonry walls with/without TCP to understand the seismic retrofit effect of TCP retrofit and the results were summarized. The results of the test showed that the TCP contributed to increase the capacity of the Shear strength and ductility of the URM walls. In addition, the deformation of the wall after cracking was substantially controlled by the carbon textile.

• Journal of the Korean Geotechnical Society
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• v.20 no.3
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• pp.129-139
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• 2004

During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the small-scaled model test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM.. From the model test in the lab, it was found out that the use of CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the gound surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was smaller than those in the other cases, and the absolute value was almost zero. Judging from the small-scaled model test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing failure of the underground pipes.

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.857-863
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• 1994

The absorption and fluorescence spectroscopic studies on the interaction between thionine (TH) and sodium dodecyl sulfate (SDS) have been carried out. The absorption and fluorescence spectral changes of TH with the changes of concentration of SDS are interpreted in terms of i) the aggregation of TH-SDS complex, ii) the stacking process of dye molecules by the association of the TH-SDS complex, iii) breakdown of the stacking due to the formation of dye-rich induced micelles, iv) redistribution of dye molecules in the surface of SDS micelles.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.8
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• pp.374-383
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• 2001

A reciprocating compressor unit with variable rotating speed driven by BLDC motor is mounted Inside hermetic chamber on an internal suspension composed of 4 roil springs and a discharge pipe. A method for predicting the dynamic behavior of compressor body is required for a reduction of transmitted vibrations. The mechanical characteristics of spring and discharge pipe stiffness properties have been obtained from experimental tests and mass moment of inertia of the compressor body iron CAD. To confirm the vibration model for the compressor body, free vibration analyses are performed with theoretical and experimental methods. results for analytical investigations on the dynamic behavior of the compressor body and the transmitted forces to the hermetic chamber through the suspension elements are Presented.

• Proceedings of the Korean Information Science Society Conference
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• 2010.11a
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• pp.21-22
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• 2010

Brain-Computer Interface (BCI) 는 뇌 신호를 이용하여 생각으로 기계 및 컴퓨터를 제어 할 수 있는 기술이다. 뇌전도(Electroencephalography, EEG) 를 이용한 본 연구는 왼쪽/오른쪽 손 상상 움직임 실험에 대해서 특징 추출 (feature extraction)에 관�� 연구로 총 9명의 피험자로부터 얻어진 뇌 전도 데이터를 이용하여 전통적인 방법 (Common Spatial Pattern, CSP 및 Fisher Linear Discriminant, FLDA)을 이용해 구한 분류 정확도와 본 논문에서 사용 된 Symbolic transfer entropy (STE)을 통해 얻어진 특징에 대한 결과를 보여 준다. 본 연구를 통하여 STE를 통한 특징 추출 방법이 의미가 있다고 생각한다.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.89-90
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• 2017

본 논문에서는 일사량 데이터를 이용한 태양광 부스트 컨버터의 MPPT 성능분석에 대한 연구를 제안한다. 실외 실험을 통해 일사계(Pyranometer)로 측정한 일사량 데이터와 그에 따른 태양광 패널의 출력 데이터를 검토하여 부스트 컨버터의 MPPT 성능을 테스트 하였으며, 측정한 일사량 데이터를 토대로 수행한 시뮬레이션과 실험결과를 비교 분석하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2001.02a
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• pp.52-52
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• 2001