• Journal of Energy Engineering
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• v.24 no.4
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• pp.24-32
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• 2015

National and international regulations on the exhaust gases of diesel engines are being strengthened, and a study of the combutsion engine and the post-porcessing system are in progress as a variety of ways. There are many techniques for the removal of nitrogen oxide like HC-SCR, LNT, Urea-SCR. And the technical development on the Urea-SCR owing to high conversion efficiency and fuel economy characteristics has being processed. This study investigated the physical/chemical properties of urea according to the change of the urea content, and were analysed the characteristic of exhaust gas. According to the increase of urea content, the contests of biuret aldehyde, phosphate content was increased and the changes of emission quantity of carbon monoxide, hydrocarbons and particulate matter in the exhaust gas was very slight. The emission quantity of NOx was decreased in accordance with increasing the urea content and it was shown to be more than 80 % in the urea solution having more than 30 wt%.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.655-655
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• 2013

그래핀은 높은 전자 이동도, 열전도도, 기계적 강도, 유연성 등의 고유한 특성으로 다양한 분야에 응용하기 위한 연구가 수행되고 있으며, 특히 전자 소자에의 적용에 관한 연구가 활발히 이루어지고 있다. 전자 소자에 적용하기 위해서는 성장 및 물성에 관한 규명, 응용 소자에 따른 특성 평가가 필요하다. 이러한 소자 특성은 그래핀 물성에 의한 영향이 기본적이지만 에칭, 전사 등의 공정 중 발생하는 오염, 표면 특성, 잔여물 등에 의한 물성 변화 또한 분석 및 제어에 관한 연구가 필요하다. 열화학증착법(thermal chemical vapor deposition)을 이용한 그래핀 합성은 구리 기판을 사용하며, 합성된 그래핀의 에칭, 박리 및 전사 공정이 있다. 이러한 공정 중 발생하는 오염 입자가 그래핀 표면에 흡착되거나, 제거되지 않은 PMMA 잔여물이 그래핀의 특성에 영향을 미치게 된다. 따라서 본 연구에서는 $CO_2$ 클러스터의 표면 충돌을 이용하여 이러한 오염 물질 및 잔여물을 제거하고 그래핀 표면을 평탄화하는 것에 관한 연구를 수행하였다. 가스 클러스터란 작동기체의 분자가 수십에서 수백 개 뭉쳐 있는 형태를 뜻하며 이렇게 형성된 클러스터는 수 nm 크기를 형성하게 된다. 그리고 짧은 시간의 응축에 의해 수십 nm 크기 까지 성장 하게 된다. 클러스터를 이용한 표면 처리는 충돌에 의한 제거에 기반 한다. 따라서 생성 및 가속되는 클러스터로부터 대상으로 전달되는 운동량의 정도가 세정 특성에 영향을 미치며 이는 생성되는 클러스터의 크기에 종속적이다. 생성 클러스터의 크기 분포는 분사거리, 유량, 분사 각도, 노즐 냉각 온도 등의 변수에 관한 함수이다. 본 연구에서는 이러한 변수들을 제어하여 클러스터를 이용한 그래핀 표면 처리 실험을 수행하였다. 평가는 클러스터 표면 처리 전과 후의 특성 비교에 기반 하였으며, 광학 현미경을 이용한 표면 형상 측정, 라만분광 분석, AFM을 이용한 표면 조도 측정, 그래핀 면저항 측정 결과를 비교하였다. 평가 결과를 통하여 표면 처리를 하지 않은 그래핀에 비하여 면저항과 표면 조도가 낮아지는 것을 확인 할 수 있었다. 또한 클러스터 세정은 300 mm 웨이퍼 크기 이상의 대면적을 짧은 시간에 건식으로 세정할 수 있다는 장점이 있어 향후 최적화를 통해 그래핀 양산 시 특성 향상을 위한 후처리 방법으로 사용될 수 있음을 확인하였다.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1598-1606
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• 1996

In order to achieve high accuracy of off-line character recognition(OCR) systems, the recognized text must be processed through a post-processing stage using contextual information. In this paper, we reclassify Korean word classes in terms of OCR word correction. And we collect combinations of Korean particles(approximately 900) linguistic verbal from(around 800). We aggregate 9 Korean irregular verbal phrases defined from a Korean linguistic point of view. Using these Korean word information and a Head-tail method, we can correct misrecognized words. A Korean character recognizer demonstrates 93.7% correct character recognition without a post-processing stage. The entire recognition rate of our system with a post-processing stage exceeds 97% correct character recognition.

• The KIPS Transactions:PartB
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• v.15B no.3
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• pp.245-252
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• 2008

We present a classification algorithm based on ant colony system(ACS) for classifying digital images. The ACS has been recently emerged as a useful tool for the pattern recognition, image extraction, and edge detection. The classification algorithm of digital images is very important in the application areas of digital image coding, image analysis, and image recognition because it significantly influences the quality of images. The conventional procedures usually classify digital images with the fixed value for the associated parameters and it requires postprocessing. However, the proposed algorithm utilizing randomness of ants yields the stable and enhanced images even for processing the rapidly changing images. It is also expected that, due to this stability and flexibility of the present procedure, the digital images are stably classified for processing images with various noises and error signals arising from processing of the drastically fast moving images could be automatically compensated and minimized.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.575-580
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• 2017

Because moire artifacts overlap with fine lesions and frequency bands, image processing software that removes moire artifacts can lead to loss of micro lesions. In this study, microscopic lesions such as microcalcification and microfracture were randomly formed on SD (Sprague Dawley) rats and image and optimized grid images were compared and analyzed using reference image and grid suppression software. The images were read by two consecutive radiologists using a McNemar's test. Among the 73 microcalcifications, in the 13 cases after grid suppression, the image of the optimized grid shows the loss of image in 3 cases, and the image after grid suppression shows statistically significant image loss (p=0.021). In all 53 fracture lines, there were 19 cases of image loss after the grid suppression, and only one case of the optimized grid showed no image loss. Therefore, the use of grid suppression software to remove moire artifacts should be carefully considered in the diagnosis of micro lesions.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.1-10
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• 2018

An experimental study was performed for the behavior of the burner flame which results from burning of the liquid hydrocarbon fuel atomized by an ultrasonic transducer. Configurations of the flame and combustion-field were caught by both high-speed camera and thermo-graphic camera, and those images were analyzed in detail through a image post-processing. As a result, the combustion-field grew and reaction-temperature rose due to the strengthening of combustion reaction with the increasing flow-rate of carrier-gas. In addition, a phenomenon of flame flickering was discussed through the comparative analysis of the variational behavior between the visible flame and IR (Infrared) flame-field. Also, the flickering frequency of the flame was confirmed through FFT (Fast Fourier Transform) analysis employing the flame area.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.412-417
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• 2022

In this paper, multi-GNSS network RTK MAC correction generation software developed based on MATLAB GUI is introduced. The software was developed as a post-processing software based on simulation data to evaluate the feasibility of an algorithm for generating correction for multi-GNSS including GPS, GLONASS, and Galileo. As a result of software operation, network RTK correction for each system of multi-GNSS is output in MATLAB file format. In this paper, to evaluate the performance of the developed software, the residual error was analyzed after applying the correction generated through the software to the user. As a result of the analysis, it was confirmed that effective network RTK correction could be generated by confirming that the residual errors of users were maintained at 10 cm or less.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.76-83
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• 2024

In the semiconductor manufacturing process, the Diffusion process generates various reactive by-products. These by-products are deposited inside the pipes of post-processing and exhaust treatment systems, posing a potential risk of substantial dust explosions. In this study, three methods material verification, selection of analysis samples, and risk analysis were employed to address the substances produced during the Diffusion process. Among the materials handled in the Diffusion process, ZrO₂, TEOD, and E-DEOS were identified as raw material capable of generating by-product dust. Test for Minimum Ignition Energy and dust explosion were conducted on the by-products collected from each processing facility. The results indicated that, in the case of MIE, none of the by-products ignited. However, the dust explosion test revealed that ZrO₂ exhibited a maximum pressure of 7.6 bar and K_st value of 73.3 bar·m/s, its explosive hazard. Consequently, to mitigate such risks in semiconductor processes, it is excessive buildup.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.34-45
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• 2004

Existing Semangeum's water balance analysis simplifies whole basin to single basin and achieved volume of effluence that produce by Kajiyama way to foundation. But Semangeum is complicated and various rice-wine strainer supply system. And there is difficulty to apply as elastic when water balance element is changed at free point. Divided to unit possession station for suitable water balance analysis model application to Semangeum in this study. And developed basin water balance model of GIS base that can do details analysis is bite about development and transfer of an appropriation in the budget of basin water resources. Achieved study including abstraction and concept design that use UML (unified modeling language) diagram for details analysis, stream network composition for rice-wine strainer supply system application, preprocessing of GIS base and postprocessing module development, model revision and verification etc. Support of this water balance analysis model is available to establish efficient water resources administration plan through outward flow process analysis of water resources. And support is considered to be possible in more convenient and, reasonable water resources administration way establishment by minimizing manual processing in systematic water resources government official to user and support diversified analysis system.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.2
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• pp.15-29
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• 2016

This study investigated the environmental and economical assessment for sewage sludge treatment options including biogasification, incineration, carbonization, drying, and solidification. Considering B/C ratio for an anaerobic digestion treatment, for $270,000m^3/d$ (over $1,150m^3/day$), B/C was 1, as the moisture content increased to 95 %, B/C was 1 for $100000m^3/d$ (capacity of $400m^3/day$). Anaerobic digestion+solidification was the most economically feasible, then Anaerobic digestion+incineration and anaerobic digestion+drying were the next economically feasible and then anaerobic digestion+carbonization was the least economically feasible. If anaerobic digestion efficiency was improved to 45%, the treatment costs for anaerobic digestion+carbonization, anaerobic digestion+incineration and anaerobic digestion+drying were decreased to 3,000~5,000 won/t and the costs for anaerobic digestion+solidification was decreased to 2,000~3,000 won/t due to increasing of the beneficial cost of the biogas production.