• 한국산학기술학회논문지
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• 제11권11호
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• pp.4635-4642
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• 2010

라텍스로 개질된 콘크리트는 높은 휨강도 뿐만아니라 부착강도 및 투수저항성이 좋은 재료특성을 제공한다. 이러한 이점을 활용한 초속경 라텍스개질 콘크리트(VES-LMC)에 관련된 연구결과는 재료에 관한 것이 대부분으로, VES-LMC로 덧씌우기 보강된 RC 보의 부착 경계면 거동특성에 대한 체계적인 연구는 미진하다. 따라서 본 논문에서는 VES-LMC로 보강된 철근콘크리트 보의 비선형 휨 거동에 대한 특성을 알아보고자 ABAQUS를 매개변수 연구를 수행한 결과 다음과 같은 결과를 얻을 수 있었다. 비선형 휨 해석을 위하여 본 논문에 적용된 모델의 적합성 여부를 확인한 결과 실험값과 비교적 유사한 경향을 보이는 것을 확인 할 수 있었다. 두께가 증가함에 따라 최대 저항강도가 증가하는 경향을 보여주었으며, 또한 강성 이 증가하여 내하력이 증진되는 결과를 확인할 수 있었다. 부착강도를 변수로 해석한 결과, 전단강도가 증가함에 따라 휨 저항능력이 향상되는 결과를 확인 하였으며, 두 이질재료의 부착능력이 구조물의 내하력에 지배적인 인자로 작용하는 것을 알 수 있었다.

• 헤리티지:역사와 과학
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• 제56권4호
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• pp.216-228
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• 2023

본 연구는 대형불화 현장 조사에 비파괴 조사장비 중 하나인 휴대용 라만 분광기를 적용하고 그 결과를 HH-XRF 데이터와 상호 비교하여 장곡사 미륵불 괘불탱에 사용된 채색 재료를 동정하였다. 대형불화에 사용된 채색 재료 분석시, 현장에서 주로 휴대용 현미경과 HH-XRF를 이용한다. 하지만 채색 재료가 경원소로 구성되어 있거나 여러 안료가 중첩 또는 혼합 채색된 경우, 비파괴 분석 데이터만으로는 해석에 한계가 있다. 또한 문화유산이라는 특성상 수습할 수 있는 시료의 양은 제한적이어서 XRD, SEM-EDS 및 라만 분광을 이용한 정밀 분석을 수행하는데 어려움이 있다. 따라서 현장 조사 시 HH-XRF 분석 데이터를 보완할 분석기술이 필요하다. 장곡사 미륵불 괘불탱을 대상으로 백색, 적색, 황색, 녹색, 청색 색상별 채색 재료에 대하여 HH-XRF로 성분을 분석하고 휴대용 라만 분광기를 적용하여 분자구조를 확인하였다. 분석결과, 백색은 연백, 적색은 진사, 석간주, 황색은 등황, 석황, 녹색은 염화동, 청색은 쪽이 사용된 것을 확인할 수 있었다. 휴대용 라만 분광기를 적용함으로써 데이터에 대한 교차검증뿐 아니라 HH-XRF로 확인이 어려웠던 혼합 채색된 안료에 대한 식별과 유기안료에 대한 정보를 획득하는데 도움이 되었다. 또한 대형불화 등 회화문화유산의 비파괴 현장 조사에 휴대용 라만이 다양하게 활용될 수 있을 것으로 판단된다.

• 제어로봇시스템학회논문지
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• 제12권4호
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• pp.389-394
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• 2006

Inaccurate localization exposes a robot to many dangerous conditions. It could make a robot be moved to wrong direction or damaged by collision with surrounding obstacles. There are numerous approaches to self-localization, and there are different modalities as well (vision, laser range finders, ultrasonic sonars). Since sensor information is generally uncertain and contains noise, there are many researches to reduce the noise. But, the correctness is limited because most researches are based on statistical approach. The goal of our research is to measure more exact robot location by matching between built VRML 3D model and real vision image. To determine the position of mobile robot, landmark-localization technique has been applied. Landmarks are any detectable structure in the physical environment. Some use vertical lines, others use specially designed markers, In this paper, specially designed markers are used as landmarks. Given known focal length and a single image of three landmarks it is possible to compute the angular separation between the lines of sight of the landmarks. The image-processing and neural network pattern matching techniques are employed to recognize landmarks placed in a robot working environment. After self-localization, the 2D scene of the vision is overlaid with the VRML scene.

• 동력기계공학회지
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• 제8권3호
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• pp.30-35
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• 2004

In the steel making industries, the continuous casting process has been applied to the number of company because of its economical benefit. Casting rolls are utilized for frictional drive and transport of solidifying slap. Dimensional tolerances, mechanical stability and surface condition of the cast roll can affect both the surface and internal quality of the product being cast. To overcome these problems, the industry is accelerating on the rate of technology improvements. Samples were overlaid on the S45C steel by submerged arc welding process. And the hardness, wear, electrochemical corrosion and oxidation tests were carried out. Test results were that all these materials were satisfying basic requirements of caster rolls. By these results, the addition of 0.1%Nb and 0.15%V increase mechanical properties and tempering resistance by its superior carbide forming characteristics in low carbon $12{\sim}13%Cr$ martensitic stainless steels.

• Journal of Welding and Joining
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• 제13권1호
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• pp.103-114
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• 1995

Plasma Transferred arc(PTA) hard facing process has been developed to obtain an overlay weld metal having excellent wear resistance. The effect of Ti, TiSi$_{2}$ and TiC powders addition on the surface of Aluminum alloy 5083 has been investigated with PTA process. This paper describes the result of test the performance of the overlay weld metal. The result can be summarized as follows 1. Intermetallic compound is formed on surface of base metal in Ti or TiSi$_{2}$ powder but the reaction with surface of base metal is little seen in TiC powder. 2. In formation of composite layer on aluminum alloy surface by plasma transferred arc welding process, high melting ceramics like TiC powder is excellent. 3. The multipass welding process is available for formation of high density of powder. But the more number of pass, the less effect of powder, it is considered, and limits of number of pass. 4. By increasing area fraction of TiC powder on Al alloy surface, in especially TiC powder the hardness increase more than 40% area fraction and 88% shows about Hv 700.

• 한국가구학회지
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• 제25권4호
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• pp.288-296
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• 2014

The approach of using the structure of the Joseon Dynasty Zen tradition we design a piece of table for outdoor camping is a necessity in modern culture as continuing to develop this research. Analyzing outdoor and camping equipment according to the time change, we focus on the study table for outdoor camping can apply the structure of the elbow. Outdoor supply is also overlaid with the change, while changing in the picnic and camping camp sensibility that was taking advantage of the individuality of each of the general camp. However, it is a surface camp that Korean culture is not to build up the camp culture that has been fixed camp culture of the world in the only development, following the camp trend of European and American. In an attempt to adhere to the trend of Korea currently camped, camping outdoor products that apply the beauty of Korea with a combination of new modern representation tradition and our culture has designed research. I have designed the camp outdoor table based on the contents mentioned above. For the design of this time, it is now possible to use appropriately in accordance with the outdoor environment conditions that are designed to upright seat sharing table in the market tables for camping and to be divided into the seat and upright.

• 한국가구학회지
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• 제21권4호
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• pp.284-292
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• 2010

This research was carried out to examine the properties of fancy cherry veneer overlaid on the PF resin bonded Meranti plywood floor, which 2.5% green tea leaf powder was applied in the UV varnishes and the adhesives for scavenging the volatile organic compounds. The results were as follows: 1. The various properties of the treated samples, such as density, moisture content, thickness swelling, bending strength(MOR), adhesion shear strength, surface abrasion, curling, cyclic delamination test with boiling water, boiling property, cold-resistance and heat resistance, acid resistance and alkali resistance, and anti-contamination property showed no significant difference between the properties of the control samples. 2.5% green tea leaf powder treated floor gave a little better results than the control for surface scratch test. 2. In case of QUV and weathering test, no difference between the treated sample and control was found. 3. The floor was discolored by adding 10% green tea leaf powder to UV coating, and the floor was also discolored to light green during by the soaking test. The color of floor was not changed up to 5% addition level.

• Asian Journal of Atmospheric Environment
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• 제12권3호
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• pp.244-254
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• 2018

Ulaanbaatar, the capital of Mongolia, is subject to high levels of atmospheric pollution during winter, which severely threatens the health of the population. By analyzing surface meteorological data, ground-based LIDAR data, and radiosonde data collected from 2008 to 2016, we studied seasonal variations in particulate matter (PM) concentration, visibility, relative humidity, temperature inversion layer thickness, and temperature inversion intensity. PM concentrations started to exceed the 24-h average standard ($50{\mu}g/m^3$) in mid-October and peaked from December to January. Visibility showed a significant negative correlation with PM concentration. Relative humidity was within the range of 60-80% when there were high PM concentrations. Both temperature inversion layer thickness and intensity reached maxima in January and showed similar seasonal variations with respect to PM concentration. The monthly average temperature inversion intensity showed a strong positive correlation with the monthly average $PM_{2.5}$ concentration. Furthermore, the temperature inversion layer thickness exceeded 500 m in midwinter and overlaid the weak mixed layer during daytime. Radiative cooling enhanced by the basin-like terrain led to a stable urban atmosphere, which strengthened particulate air pollution.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.70-77
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• 2010

In this paper, a case study of drivability and bearing capacity of large diameter steel pipe piles at PTT LNG site in Thailand is introduced. The LNG facilities were designed to be founded on steel pipe pile foundations driven into the weathered rock formation overlaid by sand layers. The drivability analyses of open ended pipe piles were carried out using GRL WEAP program and the bearing capacities of the piles were estimated. Dynamic load tests were performed to evaluate end bearing resistance, and it is shown that the measured end bearing resistance is smaller than the calculated end bearing because the plugging does not develop sufficiently in case of large diameter pipe piles.

• 한국통신학회논문지
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• 제30권7A호
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• pp.620-627
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• 2005

OFDMA 하향링크 시스템에서 단말의 불균등한 위치 분포와 다양한 QoS 요구사항의 변화에 따라 시스템에 끼치는 부정적인 영향을 줄이기 위한 적응적 hot-spot 운용 기법에 대해 제안하였다. 매크로셀의 기지국은 셀 내 피고셀의 운용을 조절하며, 예측된 user outage probability와 AHOS 이득 파라미터 값에 의해 피코셀을 켜고 끄게된다. 제안된 AHOS 기법은 다양한 시스템 환경에서 QoS outage probability를 유지하면서 시스템의 throughput을 최대화 시키는 이득을 보였다.