• 천문학논총
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• 제32권3호
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• pp.381-405
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• 2017

We give a detailed description of the installation and operation of a double-station meteor detection system which formed part of a research & education project between Korea Astronomy Space Science Institute (KASI) and Daejeon Science Highschool. A similar system is currently not existing in South Korea. A total of six light-sensitive CCD cameras were installed with three cameras at SOAO and three cameras at BOAO observatory. A double-station observation of a meteor event enables the determination of the three-dimensional heliocentric orbit in space. This project was initiated in response to the Jinju fireball event in March 2014. The cameras were installed in October/November 2014. The two stations are identical in hardware as well as software. Each station employes sensitive "Watec-902H2" cameras in combination with relatively fast f/1.2 lenses. Various fields of views were used for measuring differences in detection rates of meteor events. We employed the SonotaCo UFO software suite for meteor detection and their subsequent analysis. The system setup as well as installation/operation experience is described and first results are presented. We also give a brief overview of historic as well as recent meteor (fall) detections in South Korea. For more information please consult http://meteor.kasi.re.kr.

• Corrosion Science and Technology
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• 제7권6호
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• pp.350-361
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• 2008

Canada's oil sands contain one of the largest reserves of oil in the world. According to recent estimates, there are nearly 180 billion barrels of oil in the Canadian oil sands trapped in a complex mixture of sand, water and clay. More than 40 companies have been currently operating or developing oil sands facilities since the first production in 1967. The process of oil sands upgrading is similar with down stream refinery, but the corrosion environment in upgrading refinery is often more severe than in the refinery because of high chlorides, mineral contents, carbonic acid, heavy viscosity and fouling, higher naphthenic acid [$NA-R(CH_{2})nCOOH$], and greater sulfur contents. Naphthenic acid corrosion (NAC) which is one of the most critical corrosion issues in up & downstream refinery plants was observed for the first time in 1920's in refinery distillation processes of Rumania, Azerbaizan (Baku), Venezuela, and California. As a first API report, the 11th annual meeting stated sources and mechanism of NAC in early 1930's. API has been developing the risk base standards, such as API RP580, 571, and Publication 581 which are based on the worst NAC damage in the world since 2000. Nevertheless not only the NAC phenomena and control in Canadian sands oil process are not much widely known but also there are still no engineering guidances for the Canadian sands oil in API standards. This paper will give NAC phenomina and materials selection guidance against NA environment in Canadian oil sands upgrading processes.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.453-454
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• 2003

Most research materials (data), which are used for the study of digital mapping and digital elevation model (DEM) in the field of Remote Sensing and Aerial Photogrammetry are aerial photographs and satellite images. Additionally, they are also used for National land mapping, National land management, environment management, military purposes, resource exploration and Earth surface analysis etc. Although aerial photographs have high resolution, the data, which they contain, are not used for environment exploration that requires continuous observation because of problems caused by its coastline, as well as single - spectral and long-term periodic image. In addition to this, they are difficult to interpret precisely because Satellite Images are influenced by atmospheric phenomena at the time of photographing, and have by far much lower resolution than existing aerial photographs, while they have a great practical usability because they are mulitispectral images. The PKNU 2 is an aerial photographing system that is made to compensate with the weak points of existing aerial photograph and satellite images. It is able to take pictures of very high resolution using a color digital camera with 6 million pixels and a color infrared camera, and can take perpendicular photographs because PKNU 2 system has equipment that makes the cameras stay level. Moreover, it is very cheap to take pictures by using super light aircraft as a platform. It has much higher resolution than exiting aerial photographs and satellite images because it flies at a low altitude about 800m. The PKNU 2 can obtain multispectral images of visible to near infrared band so that it is good to manage environment and to make a classified diagram of vegetation.

• 천문학회지
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• 제52권4호
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• pp.109-119
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• 2019

While the reverberation mapping technique is the best available method for measuring black hole mass in active galactic nuclei (AGNs) beyond the local volume, this method has been mainly applied to relatively low-to-moderate luminosity AGNs at low redshift. We present the strategy of the Seoul National University AGN Monitoring Project, which aims at measuring the time delay of the $H{\beta}$ line emission with respect to AGN continuum, using a sample of relatively high luminosity AGNs out to redshift z ~ 0.5. We present simulated cross correlation results based on a number of mock light curves, in order to optimally determine monitoring duration and cadence. We describe our campaign strategy based on the simulation results and the availability of observing facilities. We present the sample selection, and the properties of the selected 100 AGNs, including the optical luminosity, expected time lag, black hole mass, and Eddington ratio.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.257-264
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• 2019

본 논문에서는 픽셀 기반 joint BDCP (bright and dark channel prior)와 계층적 양방향 필터를 적용하여 저 복잡도를 갖는 단일 영상 기반 안개 제거 기법을 제안한다. 픽셀 기반 joint BDCP는 기존의 패치 기반 DCP에 비해 연산량을 감소시키고, 픽셀 단위의 안개값 예측을 가능하게 하여 전달량 추정의 정확성을 높인다. 또한 에지를 보존하면서 평탄화 성능이 우수한 양방향 필터를 사용하여 전달량을 정련함으로써 후광 효과(halo effect)를 줄이고, 에지 성분에 대한 계층적 적용을 통해 반복 적용에 의한 연산량의 증가를 방지한다. 안개 성분이 포함된 다양한 영상에 대해 수행한 실험 결과는 제안하는 기법이 기존의 기법에 비해 우수한 안개 제거 성능을 보이면서 저 복잡도로 실행되어 다양한 분야에 응용될 수 있음을 나타낸다.

• 천문학회보
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• 제46권1호
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• pp.54.4-55
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• 2021

The Seoul National University AGN Monitoring Project (SAMP) is a welldesigned long-term AGN reverberation mapping project. SAMP focuses on the luminous AGNs out to z~0.5 with relative long time lags between AGN continuum and broad emission lines and aims to probe the high-end of the AGN broad line region (BLR) size-luminosity (R-L) relation. The pilot observations started in October 2015 for 100 AGNs to confirm the variability and the H and [O III] emission line strengths. Based on the initial variability test, 48 quasars has been continued spectroscopic monitoring since Feb. 2016 with Lick 3m and MDM 2.4m telescopes with a cadence of ~20 days. Supporting photometric monitoring in B and V band was conducted at multiple facilities including the MDM 1.3m, LOAO, and DOAO telescopes with a cadence of ~10 days. By the time of Feb. 2021, we have obtained five years spectroscopic and photometric data. More than 30 AGNs shows significant variability in five-year baseline and 16 of them show well detected lags between B-band and H. Here, we report some examples of SAMP light curves and lag detections using the first five-year data as well as the location of our 16 targets in the AGN BLR R-L relation. These measurements are consistent with the existing R-L relation and located at the high-end. With the coming data, SAMP are hopefully to report more AGNs with well detected lags. Our results demonstrate the general feasibility and potential of long-term reverberation project with medium cadence for luminous AGNs.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.38.1-38.1
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• 2009

In this paper we present the first results of summer-time F region irregularities during low solar condition observed using the Gadanki MST radar. Echoes were observed on all 20 nights of radar observations and were mostly confined to the post-midnight hours. Echo morphology is very different from the equinoxial post-sunset plume-like features reported earlier from Gadanki. Echo SNRs are lower by 25 dB than their equinoxial post-sunset counterpart, and are quite comparable to the equinoxial irregularities in the post-midnight hours, which are essentially the decaying post-sunset irregularities. The Doppler velocities, which lie in the range of $\pm$ 100 m s-1, show upward/northward motion of the irregularities during the initial phase in contrast to the observed predominant downward/southward velocities associated with the decaying equinoxial post-midnight F region irregularities. Spectral widths of the summer echoes, which are well below 50 m s-1 and are very similar to those of the decaying equinoxial irregularities, represent the presence of weak plasma turbulence. Simultaneous observations made using a collocated ionosonde show no ionogram trace during 2200-0530 LT except for a few occasions. Weak frequency type spread F observed during midnight hours occurred without prior occurrence of range spread F. Concurrent ionosonde observations made from magnetic equatorial location Trivandrum also show very similar result and thus no height rise of the F layer during the midnight hours could be monitored. The preliminary analysis suggests that the post-midnight irregularities reported here are mostly freshly generated ones. The observations are discussed in the light of other observational results reported earlier and the current under standing on the post-midnight occurrence F region irregularities in summer.

• 영어영문학
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• 제57권3호
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• pp.515-527
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• 2011

Miss Pettigrew Lives for a Day, Winifred Watson's novel of 1938, is a fairytale in novel form. Set in London of 1938, the story revolves around a one-day adventure of an ill-starred but truthful governess who is granted a second chance. This light-hearted comedy of manners was turned into a film by director Bharat Nalluri in 2008. An Anglo-American collaboration, co-scripted by Simon Beaufoy and David McGee, the film converts Watson's quaint novel into an edged heritage piece that encapsulates the 1930s, the problematic decade between the two World Wars. The film, while sustaining the narrative core of Watson's Cinderella story, attempts to place it firmly within a wider current of the novel's setting or London in 1938, tapping into the major concerns of the interwar years that engage with characters in one way or another. Stylistically, the film presents Art Deco as a main visual idiom to convey the prevailing mood of nihilism and decadence of the day. The setting here takes on significance in that it offers a telling counterpoint to the giddy superficial world of the novel. The 1930s was a highly charged decade under the threat of fascism and the Great Depression, fraught with economic and socio-political tensions and apprehensions. The film makes an explicit reference to the dismal context which is suppressed in the original text. The thirties is, therefore, portrayed as a decade of contradiction. It features gay buoyant festivity, rampant consumerism, and shifting morals and attitudes towards love, marriage and sexuality. Yet lurking beneath the surface glamour are the symptoms of crises and the deep-seated anxieties on the eve of World War II. In this way, Watson's novel of manners has been recreated into a defining film on the 1930s with its period feel propped by the atmospheric lighting, the exuberant Jazz score, and the splendid Art Deco costume and production design.

• 한국농림기상학회지
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• 제5권2호
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• pp.70-80
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• 2003

본 연구에서는 KoFlux네트워크 타워 관측소의 하나인 광릉 낙엽 활엽수림에서 최초로 직접 관측된 이산화탄소 플럭스를 보고한다. 2002년 6월부터 8월까지 에디 공분산 시스템을 다른 기상 관측 기기들과 함께 30 m 타워에 설치하였다. 관측 장소가 계곡과 같은 경사지에 위치해 있음에도 불구하고 관측된 난류 특성이, 제한된 풍향(즉, 90$\pm$45$^{\circ}$)의 경우, 평평하고 균질한 이상적인 장소에서 관측된 것들과 크게 다르지 않았다. 관측 자료 회수율은 비록 낮았으나, 분석된 예비 결과는 고무적이고, 연구해야 할 가치가 있는 것으로 나타났다. 이류 항을 무시하면, 생태계의 순 $CO_2$ 교환(NEE)은 6월에서 8월까지 약 -1.2에서 0.7 mg m$^{-2}$ s$^{-1}$의 범위를 보였다. 약한 난류가 야간 NEE에 미치는 효과를 마찰 속도(u*)및 저류 항의 산출과 관련하여 살펴보았다. 낮은 u*가 NEE에 미치는 영향은 약 0.2 m s$^{-1}$의 문턱 값을 기점으로 뚜렷하게 나타났다. 야간 NEE에 미치는 저류 항의 역할은 거의 나타나지 않았는데, 이는 밤 동안 산림 내에 축적된 $CO_2$가 경사면을 따라 배수류로 빠져나갔기 때문인 것으로 사료된다. 이는 또한 저류 항을 한 높이에서만 관측된 농도 자료를 사용함으로 생긴 오차로 인한 인위적인 결과일 수도 있다. 쌍곡선 광 반응식을 적용한 결과, 관측된 NEE 변화의 80% 이상이 설명되어, 이 산림 지역의 $CO_2$ 교환이 주로 빛에 의해 조절됨을 보여주었다. 이러한 관계식은 계절에 걸쳐 빠진 자료를 채워 넣는 자료 처리 과정에 효과적으로 사용될 수 있다. 마지막으로, 선형류 모형에 근거한 간단한 규모 분석에 의하면, 이류항의 효과가 NEE산출에 큰 영향을 미칠 수 있는 것으로 나타났다.

• Applied Biological Chemistry
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• 제23권1호
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• pp.31-44
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• 1980

토마토 상종(商種) 중(中) "강력미수(强力米壽)"를 노지(露地) 재배(栽培)한 것을 mature green stage에서 수확하여 상온(常溫) 감압하(減壓下)에서 처리(處理)하였을 때의 저장 생리(生理)와 관련(關聯)하는 주요성분(主要成分) 및 호흡량(呼吸量), 숙도(熟度), chlorophyll, 지질(脂質)등의 변화(變化)를 조사(調査)한 바, 1. 과실(果實)의 climacteric rise의 발현(發現)은 감압구(減壓區) 보다 10 일(日)이상 지연되었으며, 2, 처리기간(處理期間) 중(中) 숙도(熟度)의 변화(變化)는 감압정도(減壓程度)에 따라 차(差)가 있어, 대체(大體)로 감압도(減壓度)가 높을수록 지연되었다. 이 관계(關係)는 climacteric rise와도 밀접(密接)한 관계가 있었으며 처리구(處理區)에 관계(關係)없이 dark pink stage와 climacteric maximum는 일치(一致)하였다. 3. 과실(果實)의 색상(色相)과 관계(關係)가 깊은 chlorophyll의 감소(減少)도 상압구(常壓區)가 감압구(減壓區)보다 현저하였다. 4. 과실(果實)의 함유지질(含有脂質)은 중성지질(中性脂質), 인지질(燐脂質). 당지질(糖脂質)이었으며 그중(中) 중성지질(中性脂質)이 46%, 인지질(燐脂質)이 32%, 당지질(糖脂質)이 13%이였다. 중성지질(中性脂質)의 구성(構成)은 sterol ester, triglyc ericle, free fatty acid, 1.3 diglyceride, 1.2 diglyceride, sterol, monoglyceride 의 7종(種)이었으며, 이중(中) triglyceride가 49.3%로서 가장 함량(含量)이 많았다. 인지질(燐脂質)은 phosphatidic acid, cardiolipin, phosphatidyl choline, phosphatidyl ethanolamine, phos phatidyl glycerol, phosphatidyl inositol phosphatidyl serine의 7종(種)으로 구성(構成)되며 이중(中) phosphatidyl choline 및 phosphatidyl ethanol amine이 가장 많이 함유되고 있었다. 5. 저장중(貯藏中) 총지질(總脂質)은 시일(時日)이 경과함에 따라 점차(漸次) 감소(減少)하는 경향(傾向)이었는데 상압구(常壓區)에 비하여 감압구(減壓區)의 변화(變化)가 적었다. 중성지질(中性脂質)은 climacteric rise 및 숙도(熟度)와 관련하여 변화(變化)하였으며 climacteric onset기(期)에. 가장 많이 감소(減少)하다가 다시 상승(上昇)하는 경향(傾向)이었다. 중성지질(中性脂質) 중(中) climacteric rise 및 숙도(熟度)와 관련하여 변화(變化)한 것은 diglyceride 및 sterol ester의 2종(種)이었으며 glyceride가 중성지질(中性脂質) 전량(全量)의 변화(變化)와 동일(同一)한 경향(傾向)인데 반(反)하여 sterol ester은 climactric onset까지 증가(增加)하다가 기후(其後) 감소(減少)하였다. 인지질(燐脂質)도 저장기간(貯藏期間) 중(中) 처리구(處理區)에 관계(關係)없이 다같이 감소(減少)되었는데, 그 정도(程度)는 상압구(常壓區)에 비(比)하여 감압구(減壓區)의 변화(變化)가 적었다. 인지질(燐脂質) 중(中) ph. choline과 ph. ethanlamine은 climacteric rise및 숙도(熟度)와 관련하여 변화(變化)하였다. 중성지질(中性脂質) diglyceride 및 sterol ester와 인지질(燐脂質)의 ph. choline 과 ph. ethanol amine은 climacteric rise와 관련하여 변화(變化)하였다.