• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.733-736
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• 2002

The inside configuration of intake nozzle of vacuum cleaner greatly affects the dust-collection efficiency and acoustic-noise effect generated from flow separation Interaction between high-speed flow and internal structure. In order to improve the performance of the vacuum cleaner, flow fields inside the intake nozzles were investigated using flow visualization and FIV (Particle Image Vetocimetry) technique. The measurement to aerodynamic power, suction efficiency and noise level were also carried out. Valuable information was obtained from the experiments, revealing how to modify the intake nozzle. In this paper, the results of visualization, velocity distribution of flow fields, aerodynamic power, suction efficiency and noise level are discussed.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권6호
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• pp.346-353
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• 2000

In this paper, we developed 3 dimensional Surface Charge Method which could calculate electric fields inside GIS with a small void in solid insulator or with a metal impurity. We find a metal impurity makes much more non-uniform electric field distribution inside GIS than a small void. We also find electric field is much more increased when a metal impurity is close to solid insulator surface at high voltage conductor.

• Carbon letters
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• 제28권
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• pp.60-65
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• 2018

Linear carbon chains (LCCs) encapsulated inside the hollow cores of carbon nanotubes (CNTs) have been experimentally synthesized and structurally characterized by Raman spectroscopy and transmission electron microscopy. However, in terms of electronic conductivity, their transportation mechanism has not been investigated theoretically or experimentally. In this study, the density of states and quantum conductance spectra were simulated through density functional theory combined with the non-equilibrium Green function method. The encapsulated LCCs inside (5,5), (6,4), and (9,0) single-walled carbon nanotubes (SWCNTs) exhibited a drastic change from metallic to semiconducting or from semiconducting to metallic due to the strong charge transfer between them. On the other hand, the electronic change in the conductance value of LCCs encapsulated inside the (7,4) SWCNT were in good agreement with the superposition of the individual SWCNTs and the isolated LCCs owing to the weak charge transfer.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.612-617
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• 2007

Water meter frost in winter is a nuisance to the water administration and citizen as well. It causes stop of water supply, possibility of accident due to leakage freezing, and additional official work to change frost water meters. This study was carried out to give some basic information of water meter frost condition, to verify the effect of frost protection devices such as lagging vinyl cover, electric heater, and meter pit using subterranean heat. Nearly half of the number of the water meter frost happens in old apartment house with outer corridor, and temperature of the meter box was measured in that kind of apartment house, comparing with atmosphere temperature. The capability of three kinds of lagging vinyl cover was investigated by measuring the inside temperature of the insulated box. Also the capability of existing meter pits and new meter pits using subterranean heat was compared by measuring the inside temperature of the pits. One of the result is that the inside temperature of meter pits using subterranean heat was higher than that of the existing ones, and deeper pit causes higher inside temperature in case of using subterranean heat.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2006년도 추계학술대회 논문집
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• pp.92-95
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• 2006

The global environment is deteriorating at an alarming rate despite of enhanced international environmental regulation. Many studies have been performed to reduce pollutants. Recently, phytoremediation, plant-based technology for the removal of toxic contaminants from soil, water, and air, has been receiving large attention. Arsenic-contaminated soil is one of the major pollutant sources fur drinking water. The fern brake (Pteris erotica) has been reported as a hyper-accumulate arsenic from soils. In this study, we investigated the arsenic absorption effect on sap flow inside xylem vessels of a fern brake. The synchrotron X-ray micro-imaging technique was employed to monitor flow inside the plant non-invasively. The captured phase-contrast X-ray images show both anatomy and transport of water inside the fern brake. The refilling process of water containing arsenic inside the xylem vessels of fern brake's leaves and stems was clearly observed. These results would provide important information needed fur understanding the mechanisms of accumulation, translocation, and transformation of toxic materials in plants.

• 인터넷정보학회논문지
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• 제20권1호
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• pp.39-46
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• 2019

This paper investigates the importance of various environmental factors that have a strong influence on strawberry yields grown in greenhouse using the pattern recognition methods. The environmental factors influencing the production of strawberries were six factors such as average inside temperature, average inside humidity, average $CO_2$ level, average soil temperature, cumulative solar radiation, and average illumination. The results of analyzing the observed data using Dynamic Time Warping (DTW) showed that the most significant factor influencing the strawberry production was average soil temperature, average inside humidity, and cumulative solar radiation. Second, the results of analyzing the observed data using Multidimensional Scaling (MDS) showed that the most influential factors on the strawberry yields, such as average $CO_2$ level, average inside humidity, and average illumination were differently given for each farms. However, these results are based on the distance in 3D space and can be deduced from the fact that there is not a large difference between these distances. Therefore, in order to increase the harvest of strawberries cultivated in the farms, it is necessary to manage the environmental factors such as thoroughly controlling the humidity and maintaining the concentration of $CO_2$ constantly by ventilation of the greenhouse.

• 한국재료학회지
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• 제19권1호
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• pp.33-36
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• 2009

Inorganic-organic composite thin-film-transistors (TFTs) of ZnO nanowire/Poly(3-hexylthiophene) (P3HT) were investigated by changing the nanowire densities inside the composites. Crystalline ZnO nanowires were synthesized via an aqueous solution method at a low temperature, and the nanowire densities inside the composites were controlled by changing the ultrasonifiaction time. The channel layers were prepared with composites by spin-coating at 2000 rpm, which was followed by annealing in a vacuum at $100^{\circ}C$ for 10 hours. Au/inorganic-organic composite layer/$SiO_2$ structures were fabricated and the mobility, $I_{on}/I_{off}$ ratio, and threshold voltage were then measured to analyze the electrical characteristics of the channel layer. Compared with a P3HT TFT, the electrical properties of TFT were found to be improved after increasing the nanowire density inside the composites. The mobility of the P3HT TFT was approximately $10^{-4}cm^2/V{\cdot}s$. However, the mobility of the ZnO nanowire/P3HT composite TFT was increased by two orders compared to that of the P3HT TFT. In terms of the $I_{on}/I_{off}$ ratio, the composite device showed a two-fold increase compared to that of the P3HT TFT.

• 한국정보통신학회논문지
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• 제16권6호
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• pp.1167-1172
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• 2012

현재 우리나라에서는 일반 자동차 부품처럼 보급되고 있는 자동차 블랙박스는 하드웨어 기반의 장비로, 추후 애로사항 수정 및 추가기능 업데이트가 불가능하다. 또한 여러 가지 물리적 문제로 인하여 많은 운전자들이 불편을 겪고 있다. 현재 출시된 블랙박스는 GPS와 영상정보만 수집하여 추후 저장된 사고기록을 바탕으로 사고원인의 규명 할 때 신뢰성이 낮은 결과가 나올 수 있다. 본 논문에서는 앞에서 서술한 기존 자동차 블랙박스의 문제점을 해결하고자 기존의 블랙박스에서 취급하는 정보 이외에 OBD프로토콜을 통해 수집되는 자동차 내부정보를 다루는 안드로이드 OS용 자동차 블랙박스 어플리케이션을 개발하고자 한다.

• Journal of the Korean Data and Information Science Society
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• 제19권3호
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• pp.913-924
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• 2008

The purpose of this study is to categorize Program Provider(PP) outside and inside of the country systematically under the notion that the categorization system of the strategy group for PP is not properly organized. In this paper, not only Commercial PP but also Public PP and Homeshopping PP are also included and PP Company is consistently classified and reorganized as a strategy group in the level of contents, because existing positive study does not entirely deliberate over the characteristics of the PP contents industry inside the country. According to this frame, it is classified into 6 contents group-oriented PP strategy groups using 14 variables including vertical integration, horizontal integration, the sales, advertising revenue, license revenue, total net revenue, the number of employees and history.

• 한국정보통신학회논문지
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• 제10권8호
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• pp.1347-1351
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• 2006

초고주파 방사파 측정(microwave radiometry) 기술은 인체내부를 뚫지 않고 인체내부의 온도를 측정할 수 있는 기술로서 인체 내부의 질병이나 비정상을 조기에 진단할 수 있는 기술이다. 본 논문에서는 인체 방사파 신호를 측정하는 안테나로서 원형루프를 가진 다이폴형 안테나를 시뮬레이션하고 측정했다. 측정 결과는 $S11\leq-10dB$에 대해 $130%(0.8\sim3.8GHz)$의 초광대역 특성을 가짐으로써 다양한 질병을 가지는 인체조직의 위치와 크기를 검출하는데 적합하다고 할 수 있다.