• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.188-191
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• 2011

본 논문에서는 시간적 움직임 벡터 성분 값을 절삭하여 시간적 움직임 벡터를 저장하는데 필요한 메모리 요구량을 감소하는 방법에 대해서 제안한다. HEVC 에서 시간적 움직임 벡터는 움직임 병합 모드와 향상된 움직임 벡터 예측 방법에서 부호화 효율 향상을 위해서 사용되고 있다. 하지만 부호화해야 할 원본 영상의 공간적 해상도 및 비트 심도가 증가함에 따라 메모리에 저장할 시간적 움직임 벡터의 데이터뿐만 아니라 메모리 접근 대역폭도 크게 증가한다. 따라서 본 논문에서는 시간적 움직임 벡터 성분의 비트 심도를 조절한 후 메모리에 저장하는 방법에 대해서 제안한다. 제안하는 방법을 HM 2.0 에 구현하고 HEVC 표준화에서 사용되는 임의접근 및 저지연 실험 조건에서 실험했을 때, 평균 0.2%의 비트율 손실을 보이지만, 필요한 메모리 요구량을 약 반 정도 줄일 수 있다.

• Journal of the Korean Wood Science and Technology
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• v.27 no.1
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• pp.56-63
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• 1999

Machinability of three Korean domestic bamboo species, Phyllostachys pubescens Mazel, Phyllostachys nigra var. henonis Stapf. and Phyllostachys bambusoides S. et Z., was studied to investigate the possibility of utilization of Korean domestic bamboo species as raw material for industry. Splitting force reached a maximum within the first inch of knife travel and diminished thereafter. Parallel-sided wedge-type knife with sharpness angle of 15 degree required the lowest maximum splitting force. Roughnesses of surfaces developed during planing and sawing of bamboo were lower than those of Pinus radiata D. Don and quality of ripped surface was better than that of cross-cut surface on bamboo. 62.5 hours were required to dry 12mm-thick Phyllostachys pubescens Mazel from moisture content of 60% to moisture content of 10% at $70^{\circ}C$.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.37-44
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• 2009

Currently the reasonability of threshold values for rutting and cracking does not clearly defined at the Pavement Rehabilitation Decision Tree on national highway PMS(Pavement Management System). The goal of this study is to provide the reasonable threshold values for the national highway asphalt concrete pavement rehabilitation. To achieve this goal, test section that represents typical asphalt concrete pavement of national highway was selected and pavement export were participated. Pavement condition survey has been conducted and pavement performance data at the selected roadway section were analyzed. From this study, reasonable threshold values of Pavement Rehabilitation Decision Tree were suggested based on the pavement expert's engineering judgement. In terms of crack repairs, the application of overlay after cutting is required to deteriorated area where existing crack ratio is over 35% and just overlay is required to where crack ratio is over 20%. On rutting, rut depth over 13mm is required to overlay after cutting and rut depth over 10mm is just needed to overlay.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.170-171
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• 2000

현재 사용하고 있는 디스플레이 장치에는 표면에 무반사(antireflection), 무정전(antistatic) 코팅이 되어 있다. 이것은 전기적으로 음극선관(CRT)에서 발생되는 전자에 의해 표면에 생기는 전하의 적층을 제거하여 정전기를 방지하고 인체에 유해한 전자기파를 차단하는 무정전 기능과, 광학적으로 디스플레이 장치 표면에서 외부의 조명등과 같은 빛의 반사를 줄여 내부에서 나오는 정보(빛)가 보다 더 눈에 선명하게 들어오도록 해준다. 무반사 무정전 코팅의 투과 전도층으로는 비저항값이 낮고 가시광선 영역에서 굴절률이 높고 흡수가 적어 투과율이 높은 indium tin oxide(ITO)가 널리 연구, 사용되어 왔다. 이러한 ITO 박막 대신에 TiN 박막을 사용하여 그 위에 유전체층을 증착하여 단 2층으로 무반사 무정전 코팅을 제작 할 수 있다. TiN 박막은 절삭공구 등의 표면에 마모방지용 코팅재료로서 사용되고 있고, 부착력이 우수하며 화학적 안정성이 뛰어나 수명이 긴 박막을 제작 할 수 있는 장점을 가지고 있다. 또한 가시광선 영역에서 흡수로 인해 투과율이 ITO에 비해 상대적으로 낮지만 이점이 오히려 명도대비(contrast)의 향상을 가져온다. (중략)

• 기계와재료
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• v.21 no.4
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• pp.106-128
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• 2010

본고에서는 신흥개도국을 대표하는 BRICs에서의 일반기계산업 대일(對日) 교육 경쟁력을 수출 규모 및 경합도 추이를 통해 분석하였으며, 특히 해당 국가에서의 FTA 체결에 대한 품목별 관세율을 종합적으로 고려하여 시장 진출 확대를 꾀하기 위한 10대 전략품목을 도출하였다. 10대 전략품목은 내연기관(713), 건설광산기계(723), 섬유기계(724), 금속절삭공작기계(731), 금속가공공작기계(733), 기타 금속공작기계(737), 냉동공조기계(741), 기체 및 가스펌프(743), 운반하역기계(744), 동력전달장치(748)이며, 이들 품목에 대한 정보와 민간 차원의 협력을 통한 기술개발 및 시장 진출 전략을 제시하여 이머징 마켓에서의 일반기계산업의 수출경쟁력 향상을 꾀하고자 한다.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.1
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• pp.1-9
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• 2012

This paper explained about the sludge recycling system which retrieved the silicon and abrasive from solar cell wafer slicing. The basic process of the recycling system was multiple centrifuge and secondary processes of ultra sonic agitation, addition of alcohol-water solution and heating sludge was added for raising separation efficiency. The recycling rate was about 96% and 94% for 2N, 4N silicon respectively. The SiC abrasive recycling rate was about 80%. To retrieve the high purity of 4N silicon, the heat process in vacuum furnace was added to remove remaining impurity components.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.237-248
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• 2014

Linear cutting test is known to be very effective to determine machine parameters (i.e. thrust force and torque) and to estimate penetration rate of TBM and other operation conditions. Although the linear cutting test has significant advantages, the test is expensive and time-consuming because it requires large size specimen and high load capacity of the testing machine. Therefore, a few empirical prediction models (e.g. CSM, NTNU and QTBM) alternatively adopt laboratory index tests to estimate design parameters of TBM. This study discusses the estimation method of TBM machine parameters and disc cutter consumption using punch penetration test and Cerchar abrasion test of which the researches are rare. The cutter forces and cutter consumption can be estimated by the empirical models derived from the relationship between laboratory test result with field data and linear cutting test data. In addition, the estimation process was programmed through which the design parameters of TBM (e.g. thrust, torque, penetration rate, and cutter consumption) are automatically estimated using laboratory test results.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.231-239
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• 2013

Purpose: To design and fabricate the auto pattern maker for the development. Methods: we got the necessary data, needed in design, by using CAD. Based on the these data, we fabricated the trial product for the development of the auto pattern maker. Results: The auto pattern maker were composed with combinations of many elements; pattern making assembly, control panel, frame attachment and prober unit. The pattern making assembly was comprised of the cutter, the pattern holder, pattern remover and silence cover which could minimize the sound during the cutting process. The control panel was designed to be connected and operated with the main printed circuit board. The prober could get the eye shape data by scanning of 1.8 degrees around the groove of the frame through the encoding data according to the address. After starting, scanning was carried out in two passes, i.e. one right-handed and one left-handed. Communication connector could send the eye shape data from auto pattern maker to outer system with the RS232C transmission system. By using the one-way analysis of variance, we got the error rate of cut pattern size for ${\Phi}22mm$, ${\Phi}55mm$ and ${\Phi}62mm$. Because F-value was 0.510 and p-value was 0.601, no statistically significant differences were found. Also, the mean cutting error of the auto pattern maker was 0.0274 mm. Conclusions: we could succeed in making the trial product by applying it to the development of the auto pattern maker. The role of this auto pattern maker is to find a exact required size of lens to fit the frame by measuring the frame. The acquired data are transferred to outer system for grinding and finishing with patternless process. Also, the trial product can produce pattern to fit the frame. Therefore, it was confidently expected that the optometrists could handily produce pattern to fit the frame with this trial product and dispense the ophthalmic lens because of its efficiency and convenience compared to the past.

• Journal of Aerospace System Engineering
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• v.2 no.4
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• pp.1-6
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• 2008

In generally, the regression rate was expressed with average value and oxidizer mass flux in hybrid propulsion system. This can not represent the local value of regression rate along with oxidizer flow direction. In this study, experimental studies were performed with Separation method and Cutting method for measure local regression rate. In axial injection, the local regression rate decreases rapidly with axial location near entrance and increases with axial direction from the leading edge and the empirical formula for local regression rate with function of oxidizer mass flux and location was derived. Swirl injection regression rate has higher value at the leading edge of the fuel and comparatively uniform regression rate at the downstream. Overall regression rate of swirl injection is higher increased about 54 % than regression rate of axial injection.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.