알파/베타선 동시측정용 phoswich 검출기

김계홍,박찬희,이근우,정종헌,서범경,Kim, Gye-Hong,Park, Chan-Hee,Lee, Kune-Woo,Jung, Chong-Hun,Seo, Bum-Kyoung 한국방사성폐기물학회 2008 방사성폐기물학회지 Vol.6 No.2

The new type phoswich detector consisting of the ZnS(Ag) and plastic scintillator for alpha/beta-ray simultaneous counting was developed for monitoring radiological contamination inside pipes. The detection performance was estimated using the PSD (pulse shape discrimination) method as a function of distance between the scintillator and radioactive source. The attenuation of particles traveling through a thin film for preventing the detector from being contaminated was experimentally estimated. It is concluded from our investigation that the phoswich detector developed can provide a sufficient alpha/beta-ray discrimination. The application of a thin film for preventing the detector from being contaminated was proven to be feasible.

배관류 폐기물의 베타선 오염도 측정용 플라스틱 검출기 제작 및 특성평가

김계홍,오원진,이근우,서범경,Kim Gye-Hong,Oh Won-Zin,Lee Kune-Woo,Seo Bum-Kyoung 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.3

The characterization of radiological contamination inside pipes generated during the decommission of a nuclear facility is necessary before pipes can be recycled or disposed. But, existing direct measurements of radioactive contamination level using the survey-meter can not estimate the characteristic of contamination on a local area such as the pipe inside. Moreover, the measurement of surface contamination level using the indirect methods has many problems of an application because of the difficulty of collecting sample and contamination possibility of a worker when collecting sample. In this work, plastic scintillator was simulated by using Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. In addition, the problem of scintillator processing and transferring the detector into the pipe inside was considered when fabricating the plastic detector on the basis of simulation results. The characteristic of detector fabricated was also estimated. As a result, it was confirmed that detector capability was suitable for the measurement of contamination level. Also, the development of a detector for estimating the radiological characteristic of contamination on a local area such as the pipe inside was proven to be feasible.

변액연금의 가치산정 및 리스크 분석

엄영호 ( Young Ho Eom ),김계홍 ( Gye Hong Kim ) 韓國保險學會 2009 保險學會誌 Vol.84 No.-

상장 리츠시장의 효율성 점검

이태리 ( Taly I ),김계홍 ( Gye Hong Kim ),유승동 ( Seung Dong You ) 한국부동산분석학회 2016 不動産學硏究 Vol.22 No.2

We investigate market efficiency for Real Estate Investment Trusts (REITs) that are traded in the Korean stock market. The Korean REITs market has a history of more than 15 years; it is believed that the market has a big potential of growth and REITs can play role of an investment vehicle that induces investment capital into real estate markets. Market efficiency for REITs can be critical because in an efficient market, investors can achieve normal returns and they can not achieve more than above average-returns. Using daily market prices for four REITs stocks from 2012 and 2015, we test weak form of efficient market hypothesis. The methodologies for our empirical evidence include an ARIMA (Autoregressive Integrated Moving Average) model and both time-invariant and time-varying GARCH-M (Generalized AutoRegressive Conditional Heteroscedasticiy in Mean) Models. Our unique contribution to the literature is that with GARCH-M models our empirical evidence rejects the null hypothesis that Korean REIT stocks are efficient. We suggest that new REIT polices take account of the empirical evidence.

홈 서비스를 위한 영상 스트리밍 기술을 이용한 감시 및 제어 시스템

성경상 ( Kyung-sang Sung ),김현철 ( Hyun-chul Kim ),김계홍 ( Gye-hong Kim ),오해석 ( Hae-seok Oh ) 한국정보처리학회 2004 한국정보처리학회 학술대회논문집 Vol.11 No.2

본 논문에서는 유비퀴터스 컴퓨팅 환경에서 다양한 어플리케이션 서비스를 개발하기 위한 필수적인 요소인 멀티미디어를 바탕으로 하는 단일화 된 어플리케이션 모델을 제안한다. 제안하는 모델의 유용성을 보이기 위해, 우리는 개발되어진 어플리케이션을 테스트하기 위해 유비퀴터스 네트워크가 가능한 ubihome을 구성하여 테스트를 실시하였다. 실험 결과에 따르면 우리의 실생활에 있어 다양한 멀티미디어 어플리케이션을 확장할 수 있다는 신뢰성을 주는데 무리가 없었다. 이것은 디바이스에 대한 독립적 신뢰성을 부여하여 보다 다양한 위치에서도 어플리케이션을 적용할 수 있다는 보여주기도 한다. 제안하는 시스템을 기반으로 원격지에서도 실시간 시스템을 통하여 위험한 지역에 있어서의 제어 및 감시에 도움을 줄 뿐만 아니라, 산업에 적용하여 산업재해를 미연에 방지할 수 있는 효과도 클 것으로 기대한다.

주택연금 보증료와 월지급금에 대한 연구: 이자율위험과 장수위험 모형의 적용

장운욱 ( Woon Wook Jang ),엄영호 ( Young Ho Eom ),김계홍 ( Gye Hong Kim ) 한국보험학회 2011 保險學會誌 Vol.89 No.-

주택금융공사에서는 2007년부터 고령자들의 노후복지를 위하여 공적보증 주택연금제도를 시작하였다. 이러한 주택연금제도의 안정적 운영을 위해서는 주택연금 월지급금 및 보증료 산정 시 미래의 위험 요소들을 적절히 반영할 수 있어야 한다. 이에 본 연구에서는 주택연금 가치평가에 이자율 위험과 장수위험을 고려하기 위해 3요인 선형 이자율 기간구조모형과 Lee-Carter 사망률 모형을 각각 적용하였다. 실증분석결과에 의하면, 이자율 위험만을 고려하였을 경우, 최근 글로벌 금융위기 시기의 낮은 수준의 금리가 반영되어 높은 수준의 월지급금이 산출되었다. 반면, 장수위험 만을 고려하였을 경우에는 점차 감소하는 사망률 추세가 반영되어 현 수준보다 낮은 수준의 월지급금이 계산되었다. 이자율 위험과 장수위험을 동시에 고려하였을 경우, 감소하는 사망률 추세보다는 최근의 낮은 이자율의 영향이 주택연금 가치평가에 더 큰 영향을 주어 현 수준보다 다소 높은 월지급금이 산출되었다. 이러한 결과는 주택가격 상승률이 미래에 3.5%로 유지될 경우 현 연보증료율 0.5%가 다소 보수적으로 산정되어 있음을 보여주고 있다. 하지만 월지급금 및 보증료율은 주택가격 상승률 가정에 민감하게 반응하므로 보다 명확한 결론을 위해서는 주택가격 모형을 포함한 추가 연구가 필요할 것으로 판단된다. The Korea Housing Finance Corporation (KHFC) has provided the government guaranteed reverse mortgage loans since July of 2007 for the welfare of senior citizens. For the stable operation of this new system, the future risk factors must be considered properly when calculating the guarantee fee and monthly payments of the reverse mortgage loans. In this paper, we use 3-factor affine term structure model and Lee-Carter longevity risk model, respectively, to consider the interest rate risk and longevity risk. Considering the interest rate risk only, a high level of monthly payments is computed, which could be interpreted as a consequence of low level of interest rates during the global financial crisis. On the other hand, calculation when applying only longevity risk results in a low level of monthly payments due to diminishing trend of mortality rates. If we consider both risk factors simultaneously to the computation on the monthly payments of reverse mortgage loans, we get slightly higher numbers than the current level, which shows the interest rate risk factor is dominating the longevity risk factor. As a conclusion, this study shows the current guarantee fee determined by KHFC is computed conservatively in case the growth rate of the housing price remains in 3.5 percent in the future. However, the monthly payments values are very sensitive to the parameters of house price process, so we need further study for the concrete results.

알파 및 베타선 동시측정용 ZnS(Ag)/플라스틱 이중섬광체 검출센서 개발

서범경(Bum-Kyoung Seo),우주희(Zu-Hee Woo),김계홍(Gye-Hong Kim),이근우(Kune-Woo Lee),이동규(Dong-Gyu Lee),정종헌(Chong-Hun Jung) 한국분석과학회 2008 분석과학 Vol.21 No.2

얇은 필름 형태의 알파선 측정용 ZnS(Ag) 섬광 검출소재 제조 연구

서범경(Bum-Kyoung Seo),정연희(Yeon-Hee Jung),김계홍(Gye-Hong Kim),이근우(Kune-Woo Lee),정종헌(Chong-Hun Jung),한명진(Myeong-Jin Han) 한국분석과학회 2006 분석과학 Vol.19 No.5

부동산펀드의 효율성 점검 : 국내투자 공모펀드를 중심으로

유승동(Seung-Dong You),이태리(Ta-Ly I),김계홍(Gye-Hong Kim) 한국주택학회 2017 주택연구 Vol.25 No.3

본 논문에서는 최근 빠르게 성장하고 있는 부동산 간접투자상품인 부동산펀드의 (약형) 효율성을 분석하였다. 공모 부동산펀드의 효율성을 점검하기 위해 국내 부동산에 투자하고 있는 공모부동산 펀드의 전수를 대상으로 시간경과에 따른 시장상황과 변동성을 동시에 고려하는 효율성 점검을 위해 시변불변 및 시변가변 GARCH-M모형을 활용했다. 실증분석결과, 일부 부동산펀드의 경우 일별 시장가격이 효율적이라는 귀무가설을 기각했지만, 일부 부동산펀드의 경우 귀무가설을 기각할 수 없었으며, 모형에 따라 상이한 결과가 도출되기도 했다. 특히 시변가변 GARCH-M모형을 이용한 펀드의 효율성 점검에서는 결과의 차이점을 확인할 수 있었다. We investigate a weak form of market efficiency for Korean Real Estate Funds (REFs), the market size of which has been expanding rapidly. In particular, we focus on REFs, the underlying assets of which are composed of domestic real estate. We investigate all the traded REFs, which invest in Korean real estate markets, Due to their similar trends, nonetheless, we restricted our attention to eight; two of them invest in rental assets and six of them invest in real estate bond or mortgage. We adopt both time-invariant and time-varying GARCH-M(Generalized autoregressive conditional heteroscedasticiy in mean) models. Using daily returns of the traded REF, we fail to reject the null hypothesis that daily prices are efficient for all the REFs. With the time-varying GARCH-M model, our empirical evidence shows that six out of eight Korean REFs are of market efficiency.

여수국가산단 및 주변지역 악취발생 원인조사

송승리 ( Seung-ri Song ),오길영 ( Gil-young Oh ),서윤규 ( Yun-gyu Seo ),김계홍 ( Gye-hong Kim ),김현재 ( Hyun-jae Kim ),김인열 ( In-yeol Kim ),임항선 ( Hang-seon Lim ),안양준 ( Yang-jun An ),박귀환 ( Gwi-hwan Park ),박종수 ( Jong- 한국환경기술학회 2021 한국환경기술학회지 Vol.22 No.6

The purpose of this study is to understand the current status and cause of the distribution of odor substances in the Yeosu National Industrial Complex and its surrounding areas. Samples were analyzed by collecting 90 samples at dawn, daytime and night from a total of 15 points, 9 points in the management area, 2 points in the boundary area, and 4 points in the affected area. The analysis items include 5 meteorological factors, complex odor, 22 types of the designated odors and other Volatile Organic Compounds (VOCs). At the MA3 (Fig. 1) point in the management area, the strict emission allowance standard for complex odors was exceeded three times, Ammonia, two types of sulfur compounds, two types of aldehydes, and six types of VOCs were detected, but they were within the standard. As a result of by calculating the odor contribution, the contribution of 74.9 % or more was found at the point where butyraldehyde was detected. Therefore, in order to prevent odors at the Yeosu Industrial Complex, measures to reduce aldehydes with high odor contribution should be prioritized, and it is necessary to simultaneously investigate through real-time harmful atmospheric measurement vehicles. Based on the contents presented in this study, if the system and policies reflecting the results of the odor occurrence survey of Yeosu National Industrial Complex and surrounding areas are supplemented, the odor environment of Yeosu National Industrial Complex will be sufficiently improved.