• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.837-848
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• 2018

Monitoring technology of machining has a long history since unmanned machining was introduced. Despite the long history, many researchers have presented new approaches continuously in this area. Sound based machine fault diagnosis is the process consisting of detecting automatically the damages that affect the machines by analyzing the sounds they produce during their operating time. The collected sound is corrupted by the surrounding work environment. Therefore, the most important part of the diagnosis is to find hidden elements inside the data that can represent the error pattern. This paper presents a feature extraction methodology that combines various digital signal processing and pattern recognition methods for the analysis of the sounds produced by tools. The magnitude spectrum of the sound is extracted using the Fourier analysis and the band-pass filter is applied to further characterize the data. Statistical functions are also used as input to the nonlinear classifier for the final response. The results prove that the proposed feature extraction method accurately captures the hidden patterns of the sound generated by the tool, unlike the conventional features. Therefore, it is shown that the proposed method can be applied to a sound based automatic diagnosis system.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.384-391
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• 2005

Three dimensional finite difference elastic wave model was developed to estimate the feasibility of surface wave applications in geotechnical problems. The wave motions calculated by the developed program in this study shows good agreement with well known analytic solutions. The surface wave motions calculated from layered dam type structure can be interpreted as a infinite layer structure using dispersion curve but it is need a special source of which high energy in frequency band lower than 10 Hz to get information of physical properties in few tens meter deep. The source which has high energy in the low frequency band, however, can give defect on dam and this will make some limitation in real field applications. The dispersion curves calculated from the surface wave motion of homogeneous and center core type dam models will give rise to fatal errors if the conventional infinite layer structure used in their interpretation because the surrounding materials and boundaries of dam make some distortion in dispersion curve of surface wave. So it is strongly recommended to use three dimensional inversion model for correct interpretation and estimation of physical properties of dam materials.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.197-206
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• 2010

Recently, developed countries have continuously been trying to recognize many issues about heat island in urban area and to make up countermeasures for them. This research is designed to extract change of land cover in the area under condition of land development with satellite images and to analyze its effect on the heat change in there. Heat change upon change of land cover in daejeon was analyzed with the four Landsat satellite images taken in April 1985, August 1994, May 2001, and May 2009. In order to measure the temperature on the surface in the city, the land surface temperature was produced with Landsat TM Band 6. Heat change is to detected with it. As a result, The urban area has been increased up to 23.59 percent. On the other hand, the forest area has been decreased up to 27.91%. Due to the urbanization, the temperature on the surface in urban center was higher than surrounding area. In that case, the temperature of urban center area was higher 2.4 to $5.7^{\circ}C$ compared with the forest area.

• Korean Journal of Remote Sensing
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• v.20 no.6
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• pp.397-408
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• 2004

In this study, surface temperature which was extracted from Landsat TM band 6 was compared and analyzed with the AWS(Automatic Weather System) observation data for studying urban heat environment properties with possibility of remote sensing data application. In order to verification of the distribution properties of urban surface temperature, correlation analysis between surface temperature and NDVI, the distribution properties of urban surface temperature by land use/cover patterns were carried out by GIS spatial analysis techniques. The results presented that the spatial distribution of urban surface temperature was very different depending on various land use/cover patterns of surrounding areas. Also there was the reverse linear relationship between surface temperature and NDVI. These results will be worked as one of the major factors for environmentally sustainable urban planning considering the characteristics of weather environments in the near future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.175-179
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• 2009

this paper proposes a filter design that makes to be satisfied EMC spec. in reliability test of analogue switch for electronic equipment and air conditioning load unit. A designed electromagnetic wave filter was applied to minimize an mutual interference and surrounding environment and improve the product's quality being satisfied to EMC standard. By simulation, using a spectrum analyzer at the 30MHz~1GHz band, ISO/JASO standard frequency range, and simplified EMI chamber, energy distribution of a specific frequency band was analyzed and the capacity of the element which composed the filter was determined in order to implement the most suitable electromagnetic wave filter.In fact, it was certificated that noise decrease by filter addition to the analogue switch for electronic equipment and air conditioning load unit in Certification Authority, and confirmed that the unit is carried out a normal action without electromagnetic wave interference.

• Journal of Fashion Business
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• v.23 no.2
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• pp.156-169
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• 2019

The objective of this study was to develop lightweight, stretchable, tight-fit smart sportswear using the conductive yarns into the garment and demonstrating its usefulness. Sportswears with the ability to control LEDs with respect to lighting of the surrounding were developed by applying embroidery with conductive yarns to 2 types of men's T-shirts and 2 types of women's leggings pants for outdoor activities and exercise purposes. LEDs were applied to the front and back of men's T-shirts and to the rear of the waist of women's leggings. Men's T-shirts were printed where the LEDs were to be applied, and inside, they were embroidered with conductive threads on the hot-melt fabric to be attached, and then connected with LED. Women's pants were embroidered on the elastic band, in the form of a sine wave that gives it ability to stretch, and finally the elastic band was hidden inside the waistband. The operation of the light sensor in the dark provided the ability to protect joggers from night drivers or cyclists. LEDs were activated when the wearer turns on the fashionable device on his/her shoulder by pressing it. It was able to reduce the risk of accidents by giving recognizability to vehicles, bicycles, and athletes approaching or passing by at night, and securing safe distance from vehicles, etc. Internal embroidery technology had the same flexible and lightweight functions as ordinary clothing products, making it possible to apply to tight-fit smart T-shirts or leggings pants designs.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1963-1966
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• 2004

An ultra wide band ultra-high frequency (UHF) signal processing module was designed for on-line UHF partial discharge (PD) monitoring systems for gas-insulated switchgears (GIS). Major advantage of the unit is an improved PD detection sensitivity through minimizing the effect of surrounding interference signals. The detection sensitivity of the unit was <-60 dBm that is sufficient to detect UHF PD signals as low as 1 pC. Precise detection of PD occurred in the GIS, due to internal defects, is possible by using the signal processing unit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.17-20
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• 2006

Korean traditional houses have been developed in sympathy with natural environment and formed comfortable indoor condition by properly using surrounding natural resources including building layout, space construction and material our traditional wooden windows adjusting ambient temperature and humidity have both the functions of window and door, although they are clearly divided in the West. While window paper is attached from the outside in China and Japan, it is attached from the inside in Korea. The opening and closing mode of windows is similar and their dimensions are shown not to he standardized but diverse in terms of the characteristic of wooden furniture and that of components placed between columns. Thus this study is to look into the performance of band-lattice door of a typical traditional one by observing changes in sound absorption characteristics according to difference in thickness and finishing method of window paper and those in sound absorption characteristics with the changed thickness of air layer in traditional windows and doors.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.44-49
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• 2002

In recent years, diagnostic techniques have been investigated to detect a partial discharge(PD) in a high voltage electrical equipment. Because PD signal is very sensitive and difficult to suppress strong noises such as narrow-band radio frequency noise and random noise, the accuracy and credibility of PD measurement might be influenced by surrounding interference. Using the technique of PD detection by electromagnetic wave, we have studied the characteristics of both PD and substation-in interference signal. Also, we propose a wavelet packet transform based technique to perform a feature extraction from the interference and PD signal and a classification of the extracted features. The results show that time-frequency characteristics between PD and interference can be obviously distinguished. It is helpful for the development of the insulation diagnosis technique.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1147-1150
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• 2007

Korean traditional houses have been developed in sympathy with natural environment and formed comfortable indoor condition by properly using surrounding natural resources including building layout, space construction and material. Or traditional wooden windows adjusting ambient temperature and humidity have both the functions of window and door, although they are clearly divided in the West. While window paper is attached from the outside in China and Japan, it is attached from the inside in Korea. The opening and closing mode of windows is similar and their dimensions are shown not to be standardized but diverse in terms of the characteristic of wooden furniture and that of components placed between columns. Thus this study is to look into the performance of band-lattice door of a typical traditional one by observing changes in sound insulation characteristics according to difference in thickness and finishing method of window paper and those in sound insulation characteristics with the changed thickness of air layer in traditional windows and doors.