• Journal of the Korean Wood Science and Technology
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• 제52권3호
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• pp.276-288
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• 2024

This study was conducted to reproduce the woodworking process of Baekje wooden storage facilities. Green timber of Quercus spp. was processed using ancient woodworking tools, and the tool-trace formed in this process were compared with the tool-trace of actual excavated artifacts. In the tool-trace analysis, the length and shape of the tool-trace were objectively recorded using a 3D Scan, and that were difficult to confirm with photograph were confirmed through stereoscopic microscope. As a result, there were two types of adze's tool-trace. One of them is minute straight Blade-top trace line when trimming the wood surface and the other is Plucked trace that appear when strongly chop at the wood. When a chisel bat was not used, a long and wide continuous shape blade trace was produced. And when the chisel head was struck with the chisel bat, a straight blade-top trace was regularly observed. Saw-trace was identified in several layers with fine straight stripes. Through this, it was found that the tool-trace of the woodworking tools, which is estimated to have been used in each process, and the tool-trace remaining in the Baekje wooden storage facility coincide.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권1호
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• pp.39-50
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• 2010

유무선 데이터방송을 이용한 양방향광고 서비스는 시청자들로 하여금 시청 중인 프로그램에 능동적으로 참여할 수 있게 하고, 방송 매체와의 소통을 가능하게 만들어 그 파급효과가 매우 크다. 본 연구에서는 방송 컨텐츠 내용 중 특정 객체를 지정하고 객체의 연속되는 동적 영역정보를 추출한 후 이를 객체 형태의 양방향광고로 제작하는 시스템을 개발한다. 방송 컨텐츠 내용 중 광고객체의 선택은 광고제작자의 주관적인 판단에 따르고 선택된 객체는 TV 프로그램 진행에 따라 지속적으로 움직이며 출현과 사라짐을 반복한다. 그러므로 기존의 데이터방송용 저작도구로는 객체 형태의 양방향광고 생성이 쉽지 않다. 본 연구에서는 스케치 입력 인터페이스를 이용한 광고객체 추출 기법을 제안하고 평가 함수를 통해 입력 오류를 수정하거나 광고 효과를 높여줄 수 있는 기법을 제시한다. 또한 최종 광고객체의 시공간 영역정보를 MPEG-4 BIFS로 변환하여 디지털방송 양방향 광고로 생성하고 그 효과를 밝힌다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.292-299
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• 1998

Case hardening behavior of tool steel(SK5) was investigated after YAG laser irradiation. In the case of beam passes, martensite formed in the melt zone and in former pearlite regions of the austenization zone exhibited very high Vickers Hardness values. The molten depth and radius, micro structure, hardness were investigated as a function of defocusing distance, pulse width, and power density.

• Journal of Welding and Joining
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• 제29권2호
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• pp.80-87
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• 2011

In this study, the friction stir spot welding (FSSW) of Mg alloy sheets has been tried using an apparatus devised with a CNC milling machine to give the precise control of joining condition including tool speed. The probe tool used is made of hard metal and composed of cylindrical shoulder and pin parts. The variation of morphologies formed after the friction stir spot welding depending on the plunge speed of the tool were investigated at each rpm of tool. The history of the temperature distribution and the vertical load induced during the spot welding with friction time were measured by using an Infrared Thermal Imager (THERMA CAMTM SC2000) and a loadcell located below the specimen fixture, respectively. Tensile-shear tests were also performed to evaluate the fracture load of welded specimens. In order to characterize the friction stir spot welding of Mg alloy sheets, the variation of the fracture load was discussed on micrographic observations, temperature distribution during the FSSW according to the plunge speeds of tool.

• 소성∙가공
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• 제32권4호
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• pp.208-214
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• 2023

This paper discusses the deformation characteristics of a scaled-down automotive outer door panel with vacuum-assisted incremental sheet forming. The vacuum condition between the die and Al6052-H32 sheet with a thickness of 1.0 mm is reviewed with the goal of improving the geometrical accuracy of the target product. The material flow according to the forming tool path, including the multi-tool path and conventional contour tool path, is investigated considering the degradation of the pillow effect. To reduce friction between the tool and the sheet during incremental forming, automotive engine oil (5W-30) is used as a lubricant, and the strain field on the surface of the formed product is analyzed using ARGUS. By comparing the geometry and material flow characteristics of products under different test conditions, it is confirmed that the product surface quality can be significantly improved when the vacuum condition is employed in conjunction with a multi-tool path strategy.

• 한국기계가공학회지
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• 제15권4호
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• pp.109-117
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• 2016

For efficient deburring of burrs that form inside mechanical parts after drilling, new special deburring tool was developed specifically for the burr found at intersecting holes. In this paper, the process for finding ideal cutting conditions has been carried out to identify the efficient performance of deburring using a new tool. The burrs at the entrance and exit surface were analyzed for efficient removal. The surface roughness after deburring was also reviewed for better performance. In addition, the influence of the feed rate on deburring quality was analyzed for improved productivity. Through this process, a new deburring tool can be applied effectively to remove burrs formed at intersecting holes.

• Design & Manufacturing
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• 제14권2호
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• pp.56-61
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• 2020

Recently, research for machining next-generation micro semiconductor processes and micro patterns has been actively conducted. In particular, it is applied to various industrial fields depending on the machining method in the case of FIB (Focused ion beam) milling. In this study, intends to deal with FIB milling machining technology for ultra-precision diamond tool fabrication technology. Ultra-precision diamond tools require nano-scale precision, and FIB milling is a useful method for nano-scale precision machining. However, FIB milling has a problem of Gaussian characteristics that are differently formed according to the beam current due to the input of an ion beam source, and there are process conditions to be considered, such as a side clearance angle problem of a diamond tool that is differently formed according to the tilting angle. A series of process steps for fabrication a ultra-precision diamond tool were studied and analyzed for each process. It was confirmed that the effect on the fabrication process was large depending on the spot size of the beam and the current of the beam as a result of the experimental analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1285-1288
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• 2005

Screw rotors, the key parts of screw compressors, are used in compressing air and refrigerant due to their high productivity, compact size, low noise and maintenance. In general, a screw compressor is composed of a pair of rotors of complex geometric shape. The manufacturing cost of the screw rotors is high because the complicated helical shapes of the screw rotors are manufactured usually by the dedicated machine tools. In this study, rotor profile is divided into three parts for the efficient machining. The formed tools are designed and shared for the respective split region. By cutting the screw rotor using the formed tools, this method is more efficient than the end mill in machining rotor. Experimental results show that 4-axis machining using formed tools needs less time and has the accuracy.

• 한국주조공학회지
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• 제25권4호
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• pp.161-167
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• 2005

The experiment of hot dip interaction tests was carried out in order to study the formation behavior of interfacial reaction layer between as-received STD61 hot work tool steel and a commercial pure aluminum melt, Al-xwt.%Fe(x=0.2, 0.5, 0.8 and 1.1) alloys melt and Al-xwt.%Si(x=1.0, 4.0, 7.0 and 10.0) alloys melt, respectively. The results show that the reaction layer, over 300 ${\mu}m$ in thickness, is easily formed by the dissolution of silicon from as-received tool steel. When the iron content in the aluminum alloy is higher than 1.1 wt.%, the thickness of reaction layer decreases below 180 ${\mu}m$ by preventing iron dissolution from the tool steel. The silicon dissolved from tool steel acts as a strong promoter on the formation of reaction layer, but the alloyed silicon in molten aluminum alloys acts as an inhibitor on the formation of reaction layer.

• 중환자간호학회지
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• 제8권1호
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• pp.50-61
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• 2015

Purpose: The purpose of this study was to develop a valid tool for measuring the work environment of Korean nurses and test the validity and reliability of the instrument. Methods: This is a methodological study for developing and testing a measurement tool. The conceptual framework for the tool was formed through a literature review and in-depth interviews with clinical nurses. 260 meaningful statements were derived through this process, and 59 of the primary items were generated out of these statements. On the basis of the content validity test, 41 items were selected for the preliminary tool. A total of 350 nurses from 7 hospitals responded to the preliminary questionnaire in October 2011. Results: After the item analysis and the principal component analysis using varimax rotation methods, 11 items were deleted. Considering the conceptual framework and the scree plot, we extracted 4 factors from the final 30 items. These factors were organizational support, head nurse's leadership, support system, and relationship with coworkers, and their total variance was 54.4%. The value of Cronbach's ${\alpha}$ of the final tool was 0.92. Conclusion: The above findings revealed that the Korean Nursing Work Environment Scale (K-NWES) is an appropriate, valid, and reliable tool for evaluating the work environment of Korean nurses. Further research to perform a criterion validity test of the K-NWES is needed.