• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2198-2200
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• 1999

In this study, it is the purpose to study about design and manufacture of a pulse transformer for using in pulse generator and a pulse laser system. In this experiment, a ferite core in transformer instead of air core is used. The performance of the transformer is demonstrated by a voltage pulse waveform according to inductance of primary and secondary in transformer. As a result, the voltage pulse width is increased as increasement of inductance in transformer. And the voltage rate between primary and secondary is almost same with rate of inductance between primary and secondary.

• 한국대기환경학회지
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• 제21권2호
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• pp.243-257
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• 2005

The effects of Traffic Control Program (TCP) on the ambient urban air quality of SO$_{2}$, NO$_{2}$, O$_{3}$, and PM$_{10}$ were evaluated in Seoul metropolitan area by using the lower atmospheric vertical stability index and daily mean wind speeds. The vertical stability index; temperature lapse rate between 1000 hPa and 850 hPa geopotential height fields, were used to identify daily vertical stability index during the 2002 World Cup period where traffic amount was reportedly reduced to half the number of vehicles. The indicated air quality levels of TCP days were then compared with those of the cases observed with analogous vertical stability during the recent 3 years from 2000 to 2002. The result indicates that the effect of TCP on the primary air pollutants are found to be approximately 39$\%$, 23$\%$ and 20$\%$ lower for SO$_{2}$, NO$_{2}$ and PM$_{10}$, respectively. The secondary air pollutant; ozone, showed relatively smaller decreasing rate (13$\%$) of daily mean concentrations (even increased during the night time). The comparison of daily maximum or peak concentrations reveals that the pronounced decreasing effects of TCP on the ambient air quality for both primary and secondary air pollutants, suggesting that TCP is one of the effective strategies to control peak or higher concentrations for most urban scale air pollutants in and around the Seoul metropolitan area.

• Asian Journal of Atmospheric Environment
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• 제6권1호
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• pp.1-13
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• 2012

To identify the primary factor affected the decreased $PM_{10}$ concentration in Seoul which is the capital city of Korea, wind speed and emissions in 2003 and 2004 were analyzed. The level of air pollution is intense in Seoul and continually increased since the late 1990s. However the concentration of $PM_{10}$ has been greatly declined recently. In particular, the concentration of $PM_{10}$ decreased 14% in 2003 and 2004 excluding the Asian dust periods. It is suggested that the major factors for the decrease are differences in wind speed between the two years and the period of constant breeze. In 2003, intense Asian dust events happened frequently and it increased the concentration of total $PM_{10}$. The intense dust events were influence by the speed and duration of the wind. It is considered that the meteorological condition was the primary drive for the change of the concentration of $PM_{10}$. The decreased emissions seem to be the additional factor for the change in the concentration of $PM_{10}$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.371-384
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• 2019

Motion perception has been tremendously improved in neuroscience and computer vision. The baseline motion perception model is mediated by the dorsal visual pathway involving the cortex areas the primary visual cortex (V1) and the middle temporal (V5 or MT) visual area. However, few works have been done on the extension of neural models to improve the efficacy and robustness of motion perception of real sequences. To overcome shortcomings in situations, such as varying illumination and large displacement, an adaptive V1-MT motion perception (Ad-V1MTMP) algorithm enriched to deal with real sequences is proposed and analyzed. First, the total variation semi-norm model based on Gabor functions (TV-Gabor) for structure-texture decomposition is performed to manage the illumination and color changes. And then, we study the impact of image local context, which is processed in extra-striate visual areas II (V2), on spatial motion integration by MT neurons, and propose a V1-V2 method to extract the image contrast information at a given location. Furthermore, we take feedback inputs from V2 into account during the polling stage. To use the algorithm on natural scenes, finally, multi-scale approach has been used to handle the frequency range, and adaptive pyramidal decomposition and decomposed spatio-temporal filters have been used to diminish computational cost. Theoretical analysis and experimental results suggest the new Ad-V1MTMP algorithm which mimics human primary motion pathway has universal, effective and robust performance.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.127-137
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• 2021

미세먼지 전구체인 질소산화물(NOx)에 대한 대기배출부과금 제도가 2020년부터 국내에 도입 및 시행됨에 따라 이를 저감하기 위한 경제적인 연소기술 개발은 매우 시급한 실정이다. 본 연구에서는 해외 우드펠릿 대체재로서 REC(Renewable Energy Certificates) 확보가 가능한 국내 미이용 산림 바이오매스를 연료로 하여 0.1 MWth급 순환유동층 연소 설비에서 NOx 저감을 위한 air-staging 효과를 고찰하였다. 운전 변수로는 air-staging 적용 유무, 3차 공기 공급 높이(6.4 m, 8.1 m, 9.4 m) 그리고 air-staging 비율(1차 공기:2차 공기:3차 공기=91%:9%:0%, 82%:9%:9%, 73%:9%:18%) 변화이며 운전 변수에 대한 배기가스 내 NO와 CO 농도, 연소로 높이별 온도와 압력 프로파일, 포집된 비산재(fly ash) 내 미연탄소 함량과 연소효율을 분석하였다. 3차 공기를 가장 높은 9.4 m에서 공급한 air-staging 운전 시 NO 농도는 100.7 ppm으로 air-staging을 적용하지 않은 운전 조건(148.8 ppm)보다 32.3% 감소하지만 CO 농도는 오히려 52.2 ppm에서 99.8 ppm으로 91% 증가하였다. 더불어, NO 농도의 저감을 위한 환원영역과 CO 농도의 저감을 위한 산화영역 확보를 위해 3차 공기 공급 높이를 6.4 m로 유지하며 3차 공기 공급량을 늘리고 1차 공기 공급량을 낮춘 air-staging 운전 조건(73%:9%:18%)에서는 NO와 CO 농도가 각각 90.8 ppm과 66.1 ppm으로 air-staging 적용 조건 중 가장 감소되는 것을 확인하였다. 이러한 최적 운전 조건에서 연소효율 역시, air-staging을 적용하지 않은 운전 조건의 연소효율(98.3%) 보다 높은 99.3%임을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.743-749
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• 2010

자동 부침식 가두리 시설을 개발하기 위해 가두리 시설을 구형 부자로 단순화하여 이것의 자동 침하 및 상승 관련 제어 알고리즘 및 프로그램을 개발하였고 실내 수조 실험을 통해 그 유용성을 확인하였다. 또한 기존 연구 결과의 수치와도 비교 분석함으로써 기존 연구의 수치 모델 결과의 유용성을 재확인하게 되었다. 그리고 실물 실험에 대한 선행 연구로써 많은 변수들과 부력에 대한 비선형적인 메커니즘을 제어를 통해 극복하였으며, 이는 실물 실험에 있어 중요한 요소로 작용될 것이다.

• 한국대기환경학회지
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• 제29권4호
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• pp.390-406
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• 2013

In Korea, photochemical air pollution has drawn public attention as one of the major environmental issues since 1990s. To abate ozone and air pollution, new legislation was enacted and regulation was reinforced in conjunction with basic researches. As a result, the air quality has been much improved in terms of primary pollutant such as CO and the occurrence of extremely high ozone concentration. In Seoul, on the other hand, concentrations of ozone and exeedance hours of its national standard have increased since 2005, which is intimately coupled with $NO_2$ variations. It indicates the need for further research at long-term bases to improve our understanding on complex processes determining ozone concentrations. In this paper, the characteristics of ozone variation was analyzed with 13-year measurement data obtained in Seoul. In addition, the previous studies and their main results were summarized that have been performed in association with photochemical air pollution in Korea over the last three decades.

• 상하수도학회지
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• 제27권1호
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• pp.59-67
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• 2013

The odor occurring in the sewage system induces the displeasure, the disgust such as the headache, the vomit, etc. and increases the spiritual stress and disturbs the pleasant life of residents. These odors occur mainly in the area of combined sewage system treatment, being created in the personal sewage treatment plant such as septic tank and are incoming to sewage pipes and emitted to the outside through the manhole and the receiver, etc.; and this causes odors to the people. The Hydrogen Sulfide, the Methyl Mercaptan, the Ammonia, etc. are materials causing the odor, the more serious issue of odor is occurring since the septic tank of degradation process is being applied. The primary cause of odor is the decomposition of human feces in the septic tanks and sewage disposal facilities. The purpose of this study is reduction of hydrogen sulfide using air supplying and SOB(Sulfur-Oxidizing Bacteria). As a result of this study of the air supply system and the SOB media equipment by air supply, in case the air is injected to SOB media compared to the injection of air only, the removal efficiency the hydrogen sulfide was average 3.4 times higher.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1955-1961
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• 2008

A lot of researches on a linear induction motor(LIM) have been advanced to realize a traction system with high efficiency and performance for railway transit for a long time. However, most of them are limited in design of a LIM part such as Primary and Secondary. At a LIM which is traveling, the change of an air-gap(It occurs by a construction tolerance of a secondary reaction plate) becomes the cause which decreases a smoother ride and the efficiency of railway transit system. Therefore, uniform air-gap operation of LIM is important issue to improve the system efficiency. However, the researches which control the air-gap length of the LIM with technical and high-cost problem have been not advanced a lot. Therefore, in this research, it is introduced an air-gap control system for performance test machine of a scale-downed LIM which is able to control the air-gap length of the LIM and monitor a variety of performance changes of the propulsion system, and conducted a research on feasibility of the system based on characteristic analysis.

• Journal of Chest Surgery
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• 제42권3호
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• pp.344-349
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• 2009

배경: 기흉 환자에 있어서 임상양상은 기흉의 양과 폐의 상태에 많은 영향을 받는다. 따라서 기존 폐질환이 없는 일차성 자연 기흉에서의 대량 기흉은 증상이 심할 수 있으므로 적극적인 치료가 필요할 것이다. 그러나 대량 기흉에 있어서의 치료 방침이 병원마다 다양하다. 따라서 외과적 치료를 시행한 일차성 자연기흉 환자의 임상소견을 분석하여 향후 치료의 지표로 삼고자 한다. 대상 및 방법: 2004년 8월부터 2007년 12월까지 일차성 자연기흉으로 치료를 시행한 348명의 환자 중 대량 기흉 환자 58명을 대상으로 후향적 조사를 통하여 흉강경소견 및 치료 결과를 분석하였다. 긴장성 기흉을 포함하여 흉부엑스선상 기흉의 양이 80% 이상인 경우를 대량 기흉으로 분류하였다. 이들 모두에게 12 F 흉관을 이용한 흉관삽입술을 먼저 시행하였다. 재발성, 지속적인 공기누출, 반대편 기흉의 과거력이 있는 경우에는 수술적 치료를 시행하였고, 초발인 경우에는 흉부단층촬영 소견상 1 cm 이상의 폐기 포가 관찰되었을 때 흉강내시경을 이용한 수술적 치료를 시행하였다. 결과: 대상환자는 남자 50명, 여자 8명 이었고, 평균 연령은 28.2세$(14\sim54)$였다. 평균 입원기간은 5.3일$(2\sim10)$이었다. 49예에서 흉강내시경 수술을 시행하였고 총판치료만 시행한 경우는 9예였다. 추적기간은 평균 27.8개월$(10\sim58)$ 이었다. 술 장에서의 공기누출은 35예(71.4%)에서 관찰되었으며, 공기누출에 영향을 주는 인자를 분석한 결과 흉막유착과 유의한 상관관계를 보였다(p=0.005). 술 전 공기누출이 있는 경우 술 장에서 공기누출이 발견된 경우가 많았으나 통계적 유의성은 없었다(p=0.066). 재발율은 흉관 삽입치료를 시행한 9예 중 1예(11.1%), 수술을 시행한 49예 중 1예(2.0%)였다. 결론: 대량 일차성 자연기흉은 조기 진단 및 조기 치료가 필요하다. 흉강내시경 수술이 대량 기흉의 치료 후 재발을 방지하는데 많은 도움이 될 것이다.