• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.414-421
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• 2015

This paper presents a new method to decompose a duplicated ECG signal, which is measured from two people, to two individual ECG signals. In paper, it is shown that the duplicated ECG signal can be decomposed, provided that their SAECG signals are known. As the SAECG signal is the average of a ECG signal, it is a feature to identify individual ECG signals from the duplicated signal. Since the ECG signal is nearly periodic, so-called heart-rate, the period of each ECG signal can be found by using the autocorrelation of the duplicated signal, That is, the autocorrelation has high peaks at the multiple instants of heart-rate of each person. With the heart-rate of each person obtained by some processing, all R-peaks are identified by the SAECG signals. To be concrete, the SAECG signal of each person is repeatedly placed at the R-peak instants with his heart-rate, and the weight of each SAECG signal is computed by LMSE optimization. Finally, as adding the error signal in the LMSE optimization processing to the weighted SAECG signal, each individual ECG signal is obtained. In experimental results, we demonstrate that the duplicated ECG signal is successfully decomposed into two ECG signals.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.3
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• pp.147-153
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• 2013

There exist various types of the WEC (Wave Energy Converter), and among them, the point absorber is the most popularly investigated type. However, it is difficult to find examples of systematically measured data analysis for the design of the point absorber type of power buoy in the world. The study investigates the wave load acting on the point absorber type resonance power buoy wave energy extraction system proposed by Kweon et al. (2010). This study analyzes the time series spectra with respect to the three-year wave data (2002.05.01~2005.03.29) measured using the pressure type wave gage at the seaside of north breakwater of Hupo harbor located in the east coast of the Korean peninsula. From the analysis results, it could be deduced that monthly wave period and wave height variations were apparent and that monthly wave powers were unevenly distributed annually. The average wave steepness of the usual wave was 0.01, lower than that of the wind wave range of 0.02-0.04. The mode of the average wave period has the value of 5.31 sec, while mode of the wave height of the applicable period has the value of 0.29 m. The occurrence probability of the peak period is a bi-modal type, with a mode value between 4.47 sec and 6.78 sec. The design wave period can be selected from the above four values of 0.01, 5.31, 4.47, 6.78. About 95% of measured wave heights are below 1 m. Through this study, it was found that a resonance power buoy system is necessary in coastal areas with low wave energy and that the optimal design for overcoming the uneven monthly distribution of wave power is a major task in the development of a WEF (Wave Energy Farm). Finding it impossible to express the average spectrum of the usual wave in terms of the standard spectrum equation, this study proposes a new spectrum equation with three parameters, with which basic data for the prediction of the power production using wave power buoy and the fatigue analysis of the system can be given.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.953-956
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• 2009

본 연구는 농업용저수지유역을 대상으로 분포형 강우-유출모형을 적용해 봄으로서 차후 본 연구대상유역의 분포형 강우유출모형을 이용한 설계홍수량 산정에 활용해 보기 위한 사전연구이다. 농업용저수지유역을 대상으로 모의하기 위하여 자동수위계를 통하여 저수지 수위자료가 주기적으로 기록되고 있는 계룡저수지 유역($15.4km^2$)을 선정하였으며, 주요 공간매개변수는 30m 격자해상도로 구축하였다. 관측유량자료는 수위-내용적-방류량 관계곡선에 의하여 수위변화에 따른 내용적 변화량을 유입량으로 가정하여 환산토록 하였으며, 곡선의 진동이 다소 작고 상태가 양호한 3개 강우사상을 대상으로 분석하였다. 대상유역의 2개 강우관측소(복룡, 반포)의 강우량을 IDW 방법에 의해 공간분포시켜 적용하였으며, 모형의 분석결과, 결정계수($R^2$)는 평균0.88, 용적보존지수(VCI)는 평균 0.14, 첨두유량의 상대오차 ($EQ_p$)는 평균 $0.11m^3/s$로 분석되었다.

• Publications of The Korean Astronomical Society
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• v.5 no.1
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• pp.26-39
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• 1990

20cm 태양망원경이 소백산 천문대에서 대덕 천문우주과학연구소로 이전 설치된 후, 1987년 6월 19일 부터 1990년 11월 30일까지 흑점관측을 수행하여 343개의 흑점관측자료를 얻었다. 본 관측기간중 일일 평균 흑점상대수는 83.4로, 매일 평균 5개의 흑점군과 30개의 흑점이 관측되었다. 관측된 월평균 흑점상대수를 분석한 결과에 의하면 1986년 9월에 시작한 제22 태양활동 주기의 극대기는 1989년 9월경으로 밝혀졌다. 국제 흑점 상대수와 비교 가능한 292개의 관측 자료를 사용하여 대덕 태양망원경의 규격화 상수 K를 결정하였으며, 그 간은 소백산 천문대의 규격화 산수 0.87보다 큰 1.08로 밝혀진다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.241-247
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• 1995

A time mean surface velocity field was estimated from AVHRR/SST in the Korea Strait. Time duration of SST data set was not different from tidal period and tidal elimination was investigated. The velocity field was estimated by inverse method and compared with results of ADCP observation and results of Odamaki(1989). In accordance with results. tidal component was eliminated partially in case that there were a little difference between total time interval of 557 data set and tidal period.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1401-1405
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• 2009

현재 하천기본계획은 10년 주기로 수립되고 있다. 일반적으로 실무에서는 과거에 계산된 홍수량과 최근에 계산된 홍수량을 비교하여 큰 값을 설계홍수량으로 채택하는 경향이 있다. 동일한 유역에 대해서는 도시화와 산업화로 인하여 과거에 계산된 홍수량보다 최근에 계산된 홍수량이 대부분 클 것으로 예측되었으나, 실제로는 증가뿐만 아니라 감소하는 결과도 발견되고 있다. 따라서 본 연구에서는 이 증감의 원인을 분석하여 합리적인 설계홍수량의 채택에 기초자료를 제공하고자 한다. 이를 위하여 경기도 중 소하천 6개 유역을 대상으로하여 수립된 하천기본계획 보고서를 기초자료로 강우자료의 채택방법(임의시간), 면적감소계수(ARF) 적용, 강우의 시간분포형 변화(Huff 4분위법), 유출곡선지수(CN) 변화, 도달시간공식의 변화, 임계지속시간의 적용에 따른 홍수량의 변화를 분석하였다. 분석 결과 홍수량 산정 시 임계지속시간 적용은 평균 60%, 유출곡선지수(CN)의 증가는 평균 10%, 강우자료 임의시간 채택은 평균 21%정도 홍수량을 증가시키는 것으로 나타났다. 반면에 홍수량을 감소시키는 인자는 강우의 시간분포형을 Huff의 4분위법으로 하였을 때 평균 62%, ARF를 적용 했을 경우 평균 5%정도 감소하는 것으로 분석되었다. 도달시간의 변화는 홍수량 증감에 큰 영향이 없는 것으로 나타났다. 홍수량 증가에 가장 크게 영향을 미치는 인자는 임계지속시간의 적용여부였고, 가장 큰 감소원인으로는 강우 시간분포형의 변화였다.

• Journal of the Korean Data and Information Science Society
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• v.27 no.5
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• pp.1241-1251
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• 2016

We consider a correlated discrete-time random walk in which the current jump size depends on the previous jump size and a noncorrelated discrete-time random walk where the jump size is determined independently. By using the strong law of large numbers of Markov chains we derive the formula for the asymptotic means of the random mixture and the periodic pattern of these two random walks and then we show that there exists Parrondo's paradox where each random walk has mean 0 but their random mixture and periodic pattern have negative or positive means. We describe the parameter sets at which Parrondo's paradox holds in each case.

• Korean Journal of Construction Engineering and Management
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• v.17 no.3
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• pp.52-60
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• 2016

This study investigates and analyzes the total amount of energy consumption and $CO_2$ emission during the material manufacturing, transportation, construction, operation, and disposal phases of eight elementary school buildings in South Korea. Toward this ends, the hybrid LCA model is proposed. The life cycle energy consumption and $CO_2$ emission of eight case buildings are assessed using the hybrid LCA model with an assumption that the operation period is 40 years. As a result, the embodied(sum of the energy consumption in the material manufacturing, transportation and construction phases), operational and disposal energy were 2,279, 11,182, $228Mcal/m^2$, respectively, on average. The average embodied, operational, and disposal $CO_2$ emission were 604, 2,708, 60 kg-$CO_2/m^2$, respectively, on average. This result indicates that about 17% of life cycle energy (or $CO_2$ emission) is consumed in the material manufacturing, transportation and construction phases. Thus, it is necessary to consider the embodied energy and $CO_2$ emission to reduce the life cycle energy and $CO_2$ emission of school buildings. In addition, while the insulation standard of building have been provided based on the climate zone, energy consumption in operation phase still varied depending on the regions in this study. Thus, the insulation standard of building needs to be improved through considering the climate of regions in detail.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.557-565
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• 1984

The year-to-year fluctuations of seasonal variation of sea surface temperatures (SST) in the Korea Strait are studied based on monthly SST data for more than 50 years at Mitsushima ana Okinoshima in the strait. The frequency distribution of SST has two peaks at temperatures below and above the multi-year average, but that of SST anomalies has only one peak at the zero anomaly. More than $95\%$ of the anomalies are in the range of ${\pm}2^{\circ}C$. The harmonic constansts of seasonal SST variation vary from year to year. The standard deviations of annual means, annual amplitudes, ana semi-annual amplitudes are less than $1^{\circ}C$, and those of the annual ana semi-annual phases are about $5^{\circ}$ and less than $50^{\circ}$, respectively. The SST in the Korea Strait have a tendency to decrease their amplitudes as the annual means increase. Physical mechanisms responsible for the analyzed results are discussed in this paper.

• Environmental and Resource Economics Review
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• v.21 no.3
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• pp.465-491
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• 2012

Climate change, a result of increasing global warming, has been receiving more public attention due to its serious impact upon many industries. In this study we consider sustainable- (Green-) Growth and Green-Finance, and in particular temperature derivatives, as appropriately active responses to the world's significant climate change trends. We characterize the daily average temperatures in Seoul, South Korea with their seasonal properties and cycles of error terms. We form forecasting models and perform Monte Carlo simulations, and find that the risk-neutral values for CDD call-options and HDD put-options have risen since 1960s, which implies that the trend of temperature increase can be quantified in the financial markets. Contrary to the existing models, the Vasicek model with the explicit consideration of cycles in the error terms suggests that the significant option-values for the CDD call -options above certain exercise prices, implying that there is the possibility of explicit hedging against the considerable and stable increase in temperature.