• 천문학회보
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• 제42권2호
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• pp.52.3-53
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• 2017

Identification of gravitational wave (GW) sources in electromagnetic (EM) wave observations is important because it enables us to understand the property of the GW-emitting sources/mechanisms much better than the GW detection. For that reason, a large number of astronomers are working on observations to identify the position and the nature of GW sources. We give a short overview of the expected EM signals from GW sources and the current EM follow-up observations that have been undertaken in Korea and the world.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1012-1015
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• 2004

There have been several kinds of attempts to actively control the deflected noise behind the noise barrier. Omoto's work in 1993 would be one of the fundamental studies, where he placed the control sources uniformly parallel to the noise barrier. Following this study, Yang pointed that the average distance between the noise source and control sources is more important than the arrangement of control sources such as a straight line or an arc type distribution. In 2004, Baek tried to show optimal arrangement of control sources while keeping the average distance between the noise source and control sources. He used simulated annealing algorithm which is one of the natural algorithms for the selections of optimal control source positions, but the searching technique was a hybrid of the simulated annealing and the sequential searching to adapt to the vast amount of searching time. This study is about the performance comparison between the pure sequential searching and the hybrid one. The simulation results show very similar performance and a pure simulated annealing searching will be more beneficial for the noise reduction performance but at the cost of computing time.

• 한국환경복원기술학회지
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• 제2권1호
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• pp.29-37
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• 1999

Land cover classification is an essential basic information in natural environment management; however, land cover classification studies in Korea have not yet been proceeded to a sufficient level. At the present, only a limited number of the precedent studies that only cover definite city area has been conducted. Furthermore, there is almost no research conducted on the land cover classification schemes that could accurately classify the Korea's land cover conditions. This study primarily focuses on the land cover classification scheme which carries the most urgent priority in order to classify and to map out the Korean land cover conditions. In order to develop the most suitable land cover classification scheme, many foreign land cover classification cases and projects that are being carried out were reviewed in depth. The land cover classification scheme this study proposes comprises 3 levels : The first level consists of 7 different classes; the second level consists of 22 different classes; and the third level is made up of 50 classes. The land cover classification map will serve many important roles in natural environment management, such as the conjecture of natural habitats and estimation of oxygen production or carbon dioxide absorption capability of a forest. In water pollution modelling, the land cover classification data can be used to estimate and locate non-point sources of water pollution. If applied to a watershed, modelling it will allow to estimate the total amount of pollution from non-point sources of pollution in the water shed. The land cover classification data will also be good as a barometer data that determines defusion of air pollutants in air pollution modelling.

• 자원ㆍ환경경제연구
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• 제23권4호
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• pp.583-615
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• 2014

우리나라는 2011년 발생한 순환정전사태를 비롯하여 지난 5년간 급격한 전력소비 증가, 수요 예측 실패에 따른 전력 수급난을 겪고 있다. 또한 일본의 후쿠시마 원전사태와 국제 연료가격 상승, 기술 발전 및 적용 가능한 발전원 증가로 인해 발전 환경의 불확실성이 큰 폭으로 증가하였다. 이러한 대내외적 환경 변화로 인해 안정적 전력공급에 대한 정책적 검토가 필요하게 되었고 신규전원구성에 대한 다양한 논의가 이루어지게 되었다. 실제로 "민관 합동 워킹그룹" 에서는 에너지 기본계획 및 원전 비중 변화, 전원구성에 대한 시나리오 검토를 수행한 바 있다. 이러한 국내외 여건에 따라 본 연구에서는 제6차 전력수급기본계획과 정책 제안 그리고 우리나라의 전력 설비를 고려하여 포트폴리오 이론을 적용, 신규 전원구성 연구를 수행하였다. 본 연구의 전원 구성 결과에 따르면 향후 신재생 발전원의 비용하락과 화석 연료 발전원의 비용이 증가할 경우 신재생 발전원의 비중이 큰 폭으로 증가하며 발전믹스 내 발전원의 다양성이 증가 할 것이라는 결과가 도출되었다. 특히 위험수준(표준편차) 0.06~0.09 사이에서 가장 다양한 발전원을 보유한 효율적 전원구성이 나타남을 확인하였다. 이 밖에 기존 계획안은 효율적 곡선상에 위치하지 않기 때문에 비용-위험 기준에서 보다 개선될 수 있음을 확인하였으며 기존 방법론과 상호 보완적으로 본 연구의 방법론이 활용될 수 있음을 확인하였다. 마지막으로 본 연구 결과를 바탕으로 안정적이고 효율적인 전원믹스 운영을 위해서는 신재생 발전원의 확충과 더불어 전력저장시스템, 에너지관리시스템과 같은 전력 기술 개발 및 인프라 구축이 수반되어야 함을 확인하였다.

• Archives of Pharmacal Research
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• 제24권6호
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• pp.473-484
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• 2001

There is clearly a need for novel breast cancer chemopreventive agents with enhanced potency and specificity with tittle or no side effects. To this end, several new chemical moieties have been synthesized or isolated from natural sources. In this reviewal we have described some agents currently in use or under development for treatment or prevention of breast cancer, as well as our own strategies for the discovery of natural product modulators of estrogen biosynthesis and function. In particulars bioassay-guided fractionation of active plant extracts is a unique method for identifying agents with novel mechanisms of action, some of which should be useful for prevention of human cancer. Further, with the advent of combinatorial chemistry and high throughput screening, even greater progress may now be expected with natural product leads.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.34-34
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• 2019

About 60% of the present drugs were developed from natural products with unique chemical diversity and biological activities. Hence, discovery of new bioactive compounds from natural products is still important for the drug development. On the other hand, breakthrough made in synthetic biology has also begun to supply us with many useful compounds through manipulation of biosynthetic gene for secondary metabolites. Theoretically, this approach can also be exploited to generate new unnatural compounds by intermixing genes from different biosynthetic pathway. Considering the potential, we are studying about bioactive compounds in natural sources, as well as the biosynthesis of natural products including engineering of the secondary metabolite enzymes to make new compounds in order to construct the methodological basis of the synthetic biology. In this symposium, engineering of secondary metabolite enzymes that are involved in the biosynthesis of plant polyketides to generate new compounds in our laboratory will be mainly introduced.

• 한국환경보건학회지
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• 제24권3호
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• pp.11-17
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• 1998

Chitin is known as biodegradable natural polymer. In spite of various application of chitin derivatives from waste marine sources, commercial use of chitin has been limited due to high resistance to chemicals and the absense of proper solvents. We chitin prepared through the decalcification, bleaching and deproteination from Protunus trituberculatus shells by change of Hackman's method. Also, Microcrystalline chitin made by hydrolysis that was reduce made of resistance solvents used by dilute hydrochloric acid, ultrasonic and hydrogen peroxide. Crosslinked chitin derivatives were preparaed from chitin with crosslink agents(epichlorohydrin, 1,3-dichloropropanol) follwed by crosslinkage at 6C position. The effects of these parameters on chitin dervatives were invastigated by IR, DSC, XRD, BET, PSA and SEM. SEM analysis showed that both chitin and crosslinked chitin had a particle shaped morphology.

• 한국소음진동공학회논문집
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• 제21권6호
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• pp.546-552
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• 2011

In this study, noise sources of a reducer which is combined a spiral bevel gear and a planocentric gear are identified by experimental method and the noise was reduced by the structure modification of the reducer. In order to identify the noise sources, noise and vibration signals were measured by microphone and accelerometer and these signals were analyzed with waterfall plot. In addition, the frequency response functions were obtained to prove the noise and vibration sources. It was found that the resonance was generated by the gear mesh frequencies and natural frequency of the reducer. The noise of the reducer could be reduced by structure modification.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.51-56
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• 2011

In this study, noise sources of a reducer which is combined a spiral bevel gear and a planocentric gear are identified by experimental method and the noise was reduced by the structure modification of the reducer. In order to identify the noise sources, noise and vibration signals were measured by microphone and accelerometer and these signals were analyzed with waterfall plot. In addition, the frequency response functions were obtained to prove the noise and vibration sources. It was found that the resonance was generated by the gear mesh frequencies and natural frequency of the reducer. The noise of the reducer could be reduced by structure modification.

• 한국환경보건학회지
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• 제19권3호
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• pp.41-45
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• 1993

To study the prevention of mycotoxin contamination, a large number of sample sources were collected, and Penicilliurn sp. were isolated. TLC and HPLC methods were applied to confirm the patulin producing abilities of isolated strains. From 321 sample sources such as fruit (46), rice (31), corn (19), barley (22) and soil (38), 203 strains of Penicilliurn sp. were isolated. By the result of TLC, 21 strains were assumed to be patulin producing strains, but as a result of HPLC, only 17 strains produced patulin. Among them, E-219 strain showed highest patulin level as 0.12 mg/ml broth.