• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.551-556
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• 2008

Possibility of the remote eavesdropping through window glass is investigated using a laser sensor. Various thicknesses and types of glass windows are excited by maximum length sequency (MLS) signal and the vibration sound is detected by a laser doppler vibrometer. Intelligibility of the detected sound is evaluated using the speech transmission index (STI), which is based on the modulation transfer function (MTF). In order to identify the disturbing effect, different level of disturbing wave is generated by an outside speaker and a window shaker attached on the glass window. On the different thickness of glass windows, decrease effect of the speech intelligibility is analysed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.888-894
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• 2007

The speech sound is detected by the vibration measurement of the window glass. In this study, we investigate the effect of the disturbing waves by background noise and window shaker excitation on the speech intelligibility of the detected sound. Based upon Modulation Transfer Function(MTF), speech intelligibility of the sound is objectively estimated by Speech Transmission Index(STI) As the level of the disturbing wave varies, variation of the speech intelligibility is examined. Experimental result reveals how STI is influenced by the level and frequency characteristics of the disturbing wave. By using a customized window shaker for disturbing sound, we evaluate the efficiency and the frequency characteristics of the anti-eavesdropping system. The purpose of the study is to provide useful information to prevent the eavesdropping through the window glass.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.55-60
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• 2007

Possibility of the eavesdropping is investigated on a conference room-glass window coupled system. Speech intelligibility analysis is performed on the eavesdropping sound of the glass window. Using MLS(Maximum Length Sequency) signal as a sound source, acceleration and velocity responses of the glass window are measured by accelerometer and laser doppler vibrometer. MTF(Modulation Transfer Function) is used to identify the speech transmission characteristics of the room and window system. STI(Speech Transmission Index) is calculated by using MTF and speech intelligibility of the vibration sound is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.138-139
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• 2018

The purpose of this study is to analyze the work of the existing manpower dependent cleaning method by investigating the window cleaning site. In this study, detailed work contents were confirmed by on-site investigation and interview with experts, and the relationship, procedure, repetition work, and time required for each work were analyzed. The future analysis results will be used as a basic data for comparative analysis of productivity and economical efficiency with the window cleaning device to be developed.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.1-10
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• 2016

To improve the sound insulation performance of laminated glass in high speed trains, it is beneficial to study the relationship between the characteristics of interlayer films and the acoustical performance. In addition to those of conventional PVB (polyvinyl butyral), the dynamic mechanical properties of PVB derivatives and PC (polycarbonate), which are candidates for interlayer films, were analyzed. We assumed that PVB-HEMU, which has a glass transition temperature ($T_g$) around room temperature and a large tan ${\delta}$ (loss tangent) value, can be made to damp efficiently. The damping capability was tested utilizing sound transmission loss measurement and simulation under the identical structure of laminated glass in high speed trains. We also built a database for analysis of relations between interlayer film characteristics and acoustical performance; this was followed by the determination of sound transmission loss using the intensity technique and FEA.

• The Science & Technology
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• v.35 no.5 s.396
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• pp.24-25
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• 2002

1998년 설립된 벤처기업 (주)디엠디스플레이는 리모콘을 누르면 테라스의 유리창이 TV스크린으로 바뀌는 스마트 유리를 순수 국내기술로 개발하여 상용화해 화제를 모으고 있다. 이미 양산체제로 들어간 이 회사는 2001년 산업자원부로부터 '세계 일류상품' 생산기업으로 지정받았다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.447-451
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• 1997

주변에 소음 유발 기기가 많아 소음 레벨이 열악한 태안화력 1,2호기 사이의 사무실을 제어 대상으로 하여 여러 형태의 유리창에 대한 투과 손실을 이론적으로 예측하였으며, 기존 형태를 대체하여 현장에 적용시의 삽입 손실을 추정하였다.

• The Science & Technology
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• v.28 no.9 s.316
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• pp.68-71
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• 1995

지난 7월25일 오후7시경 서해 백령도 부근에서 규모4.0의 지진이 발생했다. 비록 50초간의 별 피해없는 약진이었지만 백령도에서는 물론 서울을 비롯한 경기 서부북 일대에서도 건물 유리창이 흔들릴 정도의 수준이었다. 이에따라 한반도 지진발생현황을 살펴보고 우리 원전의 안전성을 점검해본다

• Journal of the Korean housing association
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• v.17 no.4
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• pp.101-109
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• 2006

The purpose of this study was to suggest ways on reducing the cooling and heating energy cost of the officetel building with the multiple glazing windows according to Life Cycle Costing. This study consisted of an hour-by hour energy simulation program and further data from the EnergyPlus V1-2-2 to the four pane type windows that were applied with 2 low-e polyester film and krypton gas to the officetel model building. It was determined that the four panes type windows that had 2 low-e polyester film and krypton gas applied to, them showed a cooling and heating cost reduction over traditional double glazed windows that were filled with air. According to this study, as well as the information from chart 4.5 and the LCC it was determined that the present value of the four panes of windows that had 2 low-e polyester film and krypton gas applied to them showed. a 11.4% reduction in heating and cooling in comparison to the traditional double glazed windows that were filled with air.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.18-23
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• 1998

Development of an automobile antenna printed on-glass for FM radio receptions was discussed in this study. NEC-2 code was used as the design tool in this research. An omnidirectional radiation pattern and reception power level of the newly designed antenna were compared with those of the conventional pole antenna for the evaluation of its performance. The test sites for the reception power level measurement were chosen by their signal enbironmental condition, such as multipath fading, and strong field effect area.