Cognitive Radio 시스템을 위한 간섭온도 인지 기반의 적응전송 기법

홍민기,김재운,김현욱,신요안,Hong, Min-Ki,Kim, Jae-Woon,Kim, Hyun-Wook,Shin, Yo-An 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.9c

In this paper, we present an adaptive transmission system model to establish the baseline for wireless adaptive transmission using CR (Cognitive Radio) systems, and propose an adaptive transmission scheme based on IT (Interference Temperature) cognition for CR systems in the presented system environment. The proposed CR adaptive transmission scheme is the method that provides the CR user with the maximum transmit power in the range of not causing any interference to the incumbent user and guaranteeing the optimal throughput by applying CR-AMC (CR-Adaptive Modulation and Coding) in the given channel state. Simulation results show that in case of using the proposed CR adaptive transmission scheme, there is little degradation of BER performance, while causing no interference to the incumbent user. At the same time, the proposed scheme guarantees the optimal throughput to the CR user in the given channel state. 본 논문에서는 CR (Cognitive Radio) 시스템의 무선 적응전송에 대한 연구 기반을 마련하기 위해 CR 시스템 환경 및 시나리오 모델을 제시하고, 제시된 시스템 환경 모델에서 CR 시스템을 위한 간섭온도 인지 기반의 적응 전송 기법을 제안한다. 제안된 CR 적응전송 기법은 CR-APC (CR-Adaptive Power Control)를 사용하여 주 사용자에게 간섭 영향을 미치지 않는 범위 내에서 CR 사용자에게 최대 전송전력을 제공하고, CR-AMC (CR-Adaptive Modulation and Coding)를 적용하여 주어진 채널 상태에서 CR 사용자에게 최적의 전송률을 보장할 수 있는 방식이다. 모의실험 결과, 제안된 CR 적응전송 기법을 사용한 경우 주 사용자에게는 간섭 영향을 거의 미치지 않아 비트오율 성능 열화가 거의 없었으며, CR 사용자에게는 주어진 채널 상태에서 최적의 전송률을 보장할 수 있음을 확인할 수 있다.

WRF 기상자료의 토양수분 모형 적용을 통한 밭 토양수분 및 필요수량 산정

홍민기,이상현,최진용,이성학,이승재,Hong, Min-Ki,Lee, Sang-Hyun,Choi, Jin-Yong,Lee, Sung-Hack,Lee, Seung-Jae 한국농공학회 2015 한국농공학회논문집 Vol.57 No.6

The aim of this study was to develop a soil moisture simulation model equipped with meteorological data enhanced by WRF (Weather Research and Forecast) model, and this soil moisture model was applied for quantifying soil moisture content and irrigation requirement. The WRF model can provide grid based meteorological data at various resolutions. For applicability assessment, comparative analyses were conducted using WRF data and weather data obtained from weather station located close to test bed. Water balance of each upland grid was assessed for soils represented with four layers. The soil moisture contents simulated using the soil moisture model were compared with observed data to evaluate the capacity of the model qualitatively and quantitatively with performance statistics such as correlation coefficient (R), coefficient of determination (R2) and root mean squared error (RMSE). As a result, R is 0.76, $R^2$ is 0.58 and RMSE 5.45 mm in soil layer 1 and R 0.61, $R^2$ 0.37 and RMSE 6.73 mm in soil layer 2 and R 0.52, $R^2$ 0.27 and RMSE 8.64 mm in soil layer 3 and R 0.68, $R^2$ 0.45 and RMSE 5.29 mm in soil layer 4. The estimated soil moisture contents and irrigation requirements of each soil layer showed spatiotemporally varied distributions depending on weather and soil texture data incorporated. The estimated soil moisture contents using weather station data showed uniform distribution about all grids. However the estimated soil moisture contents from WRF data showed spatially varied distribution. Also, the estimated irrigation requirements applied WRF data showed spatial variabilities reflecting regional differences of weather conditions.

천남성(天南星)음독에 의한 구강과 인두의 충혈과 통증 및 부종의 1례

홍민기,박주옥,왕순주,Hong, Min-Ki,Park, Ju-Ok,Wang, Soon-Joo 대한임상독성학회 2003 대한임상독성학회지 Vol.1 No.1

Korean people use a lot of herbal agents for medical purposes, such as curing diseases, improving health state, but some of the herbal agents have toxic side effects. In terms of toxicology, herbal agents classified into 3 categories generally nontoxic, potentially toxic and toxic. But, there are few studies about the mechanisms and clinical features of intoxication of herbal agents. So detoxification or initial treatment of these agents is very difficult to clinicians in hospital. Authors experienced an uncommon case of intoxication after Arisaematis Rhizoma Ingestion. We report this case with review of Arisaematis Rhizoma.

Colloidal Silica를 이용한 Silylated Waterborne Polyurethane/Silica Nanocomposite의 제조

홍민기 ( Min Gi Hong ),신용탁 ( Yong Tak Shin ),최진주 ( Jin Joo Choi ),이원기 ( Won Ki Lee ),이경배 ( Gyoung Bae Lee ),유병원 ( Byung Won Yoo ),이명구 ( Myung Goo Lee ),송기창 ( Ki Chang Song ) 한국화학공학회 2010 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.48 No.5

Halbach Array와 Same Direction Skew를 통한 Axial Flux Motor의 성능 향상에 관한 연구

홍민기(Min-Ki Hong),표현조(Hyun-Jo Pyo),이예서(Ye-Seo Lee),최도현(Do-Hyeon Choi),김원호(Won-Ho Kim) 대한전기학회 2023 대한전기학회 학술대회 논문집 Vol.2023 No.7

최상위 소득 비중의 장기 추세 (1958∼2013년)

홍민기(Hong Min ki) 한국경제발전학회 2015 경제발전연구 Vol.21 No.4

This paper provides a homogeneous series of top incomes in Korea from 1958 to 2013 using tax return data. The top incomes sharply increased in 1960s and 1970s, stagnated in 1980's, and surged again since 2000. Korea had a very fair distribution of wealth and income in 1950s. Compressive growth in Korea generates compressive development of income concentration. While individuals in top percentile were overwhelmingly rentiers deriving most of their income from wealth holding before World War Ⅱ in many developed countries, individuals in top percentile rely mostly on labor income from 1950s on in Korea. During late 1980s in which the union density sparked highly, the top wage share dropped until 1995 when a new government began to introduce labor market policies against workers. After 1997, the top wage and income shares increased while the bargaining power of workers was decreasing. Also, the polarization of business income played a great role of the concentration of income distribution after 2000.

최상위 임금 비중의 장기 추세 (1958-2013)

홍민기 ( Min Ki Hong ) 한국산업노동학회 2015 산업노동연구 Vol.21 No.1

This paper studies the top wage shares from 1958 to 2013 in Korea using tax return data. In addition, this paper examines the occupational composition of the top wage group. The results are summarized as follows. First, the top 10% share has increased from 1958 to 1978 and then showed U shaped trend. In the 1960’s and 1970’s, the wage inequality increased along with rapid economic growth. In the 1980``s and the first half of 1990’s, the wage inequality decreased despite of moderate economic growth. The top wage share increased sharply from the year of 1996. Second, the increase of the top 5% share is the main source of the increase of the top 10% wage share in Korea, meanwhile the top 1% share leaded the wage inequality in the U.S. Third, the top 1% wage group is mainly composed of the managers and the professional such as doctors, pharmacists, financial dealer and traders. The recent trend shows that the white collar workers with high wages replace the mangers in the top 1% group.

비정규노동 : 정규-비정규근로의 임금격차 추정에 대한 논의

홍민기 ( Min Ki Hong ) 한국산업노동학회 2010 산업노동연구 Vol.16 No.2

This paper studies sore issues on the estimation of wage differentials between non-regular and regular works. Because the worked hours are not the choice variable in Korea, one needs to be careful to include the part-time or daily workers whose worked hours are very short. Also, there is a problem of selection of dependent variable: wage or hourly wage. Controlling for tenure and gender generate overcontrolling problem in the estimation. Previous studies controlled for many characteristics and hence in fact measure the degree of discrimination instead of differentials. Panel fixed effects estimators suffer from the attenuation bias due to measurement errors. Results show that taking account for the unobserved heterogeneity results in a little change in the wage differentials.

졸업정원제와 대졸-고졸 임금격차

홍민기 ( Min Ki Hong ),조가원 ( Ka Wnon Cho ) 한국경제통상학회 2011 경제연구 Vol.29 No.3

This paper empirically studies effects of the graduation quota system on wage differentials between college and high school graduates. We estimate a semiparamteric model that includes nonparametric interaction terms of cohort and education. Results show that (1) the significant drops in college premium occurred with a lag and lasted for the younger generation, and (2) underemployment of college graduates, decreased wage differentials of low-skilled jobs, and decreased skill premiums of high school graduates are the main causes of the drops in college premium. They suggest that the effects of the graduation quota system have centered around the low-waged workers.

WRF 기상자료를 활용한 밭 토양수분 및 필요수량의 산정

홍민기 ( Min-ki Hong ),이상현 ( Sang-hyun Lee ),이승재 ( Seung-jae Lee ),이성학 ( Sung-hack Lee ),최진용 ( Jin-yong Choi ) 한국농공학회 2015 한국농공학회 학술대회초록집 Vol.2015 No.-

밭의 작물 재배를 위한 적정 관개 계획 수립을 위해서는 토양의 수분 상태에 대한 정확한 파악이 필요하다. 본 연구에서는 밭 지역을 격자 형태로 분할하여 작물의 증발산량, 토양수분 그리고 관개 필요수량을 산정할 수 있는 격자 기반 토양 물수지 모형을 개발하였다. 본 모형은 개념적 물수지 모형으로써 밭 지역의 토층을 4개 구간으로 분할하고 토층별 토양수분소비형(Soil Moisture Extract Pattern)을 고려하여 작물 소비수량 및 토층별 토양수분을 산정하였다. 또한 산정된 소비수량 및 토양수분 정보를 이용하여 작부기간 중 필요한 관개수량을 제시하였다. 본 연구에서 사용된 WRF(Weather Research and Forecasting) 모형은 복사, 온도, 바람, 강수 및 상대습도 등의 기상정보를 고해상도의 격자 형태로 제공하는 것이 가능한 중단기 기상예측모형이다. 본 연구에서는 국가농림기상센터(National Center of Agro-Meteorology)에서 제공한 WRF 기상자료를 토양 물수지 모형에 적용하여 작물 증발산량 및 토양수분 산정을 실시하였으며 WRF 기상자료의 적용 효과를 분석하기 위해 지배 관측소의 기상 자료를 적용하였을 경우와 WRF 기상자료 적용 시의 토양 물수지 분석 결과를 비교하였다. 본 연구는 경기도 여주시 점동면에 위치한 청미천 부근의 밭 지역을 시범 지역으로 하였으며 모의기간은 2014년 9월 10일부터 2014년 9월 29일로 하였다. 밭 지역에 해당하는 토지이용도, 토성도 및 작물지도는 가로 및 세로가 모두 90m인 격자로 분할되어 입력 자료로 활용되었다. WRF 기상자료 역시 격자로 생성되며 본 연구에서는 가로 및 세로의 크기가 모두 270m(d04), 810m(d05)인 경우의 자료를 적용하였다. 연구 결과 각 격자의 작물 증발산량, 토양수분 및 관개 필요수량(Potential Irrigation Water Requirement)을 일별 산정하여 시계열 형태로 분석하였으며 작부기간 동안의 누적 증발산량 및 잠재적 필요수량의 지역적 분포도 분석도 실시하였다. 더불어 기상자료의 해상도 차이에 따른 밭 지역 물수지 계산 결과의 차이를 비교함으로써 WRF 기상자료의 적용을 통한 물수지 분석 결과의 특징을 고찰하였다. 토양수분 및 증발산량을 실측하고 본 모형의 모의 결과와 비교함으로써 물수지 모의 성능을 검정하는 것을 향후 연구 계획으로 한다.