• 대기
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• 제25권1호
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• pp.67-83
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• 2015

Predicting the location and intensity of precipitation still remains a main issue in numerical weather prediction (NWP). Resolution is a very important component of precipitation forecasts in NWP. Compared with a lower resolution model, a higher resolution model can predict small scale (i.e., storm scale) precipitation and depict convection structures more precisely. In addition, an ensemble technique can be used to improve the precipitation forecast because it can estimate uncertainties associated with forecasts. Therefore, NWP using both a higher resolution model and ensemble technique is expected to represent inherent uncertainties of convective scale motion better and lead to improved forecasts. In this study, the limited area ensemble prediction system for the convective-scale (i.e., high resolution) operational Unified Model (UM) in Korea Meteorological Administration (KMA) was developed and evaluated for the ensemble forecasts during August 2012. The model domain covers the limited area over the Korean Peninsula. The high resolution limited area ensemble prediction system developed showed good skill in predicting precipitation, wind, and temperature at the surface as well as meteorological variables at 500 and 850 hPa. To investigate which combination of horizontal resolution and ensemble member is most skillful, the system was run with three different horizontal resolutions (1.5, 2, and 3 km) and ensemble members (8, 12, and 16), and the forecasts from the experiments were evaluated. To assess the quantitative precipitation forecast (QPF) skill of the system, the precipitation forecasts for two heavy rainfall cases during the study period were analyzed using the Fractions Skill Score (FSS) and Probability Matching (PM) method. The PM method was effective in representing the intensity of precipitation and the FSS was effective in verifying the precipitation forecast for the high resolution limited area ensemble prediction system in KMA.

• 천문학회보
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• 제37권2호
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• pp.123.2-123.2
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• 2012

We investigate the solar flare occurrence rate and daily flare probability in terms of the sunspot classification supplemented with sunspot area and its changes. For this we use the NOAA active region data and GOES solar flare data for 15 years (from January 1996 to December 2010). We consider the most flare-productive eleven sunspot classes in the McIntosh sunspot group classification. Sunspot area and its changes can be a proxy of magnetic flux and its emergence/cancellation, respectively. We classify each sunspot group into two sub-groups by its area: "Large" and "Small". In addition, for each group, we classify it into three sub-groups according to sunspot area changes: "Decrease", "Steady", and "Increase". As a result, in the case of compact groups, their flare occurrence rates and daily flare probabilities noticeably increase with sunspot group area. We also find that the flare occurrence rates and daily flare probabilities for the "Increase" sub-groups are noticeably higher than those for the other sub-groups. In case of the (M+X)-class flares in the 'Dkc' group, the flare occurrence rate of the "Increase" sub-group is three times higher than that of the "Steady" sub-group. Our results statistically demonstrate that magnetic flux and its emergence enhance the occurrence of major solar flares.

• 한국정보시스템학회지:정보시스템연구
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• 제16권3호
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• pp.1-20
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• 2007

Most researches on the corporate credit rating are generally classified into the area of bankruptcy prediction and bond rating. The studies on bankruptcy prediction have focused on improving the performance in binary classification problem, since the criterion variable is categorical, bankrupt or non-bankrupt. The other studies on bond rating have predicted the credit ratings, which was already evaluated by bond rating experts. The financial institute, however, should perform effective loan evaluation and risk management by employing the corporate credit rating model, which is able to determine the credit of corporations. Therefore, this study presents a corporate credit rating method using business failure probability map(BFPM) and AHP(Analytic Hierarchy Process). The BFPM enables us to rate the credit of corporations according to business failure probability and data distribution or frequency on each credit rating level. Also, we developed AHP model for credit rating using non-financial information. For the purpose of completed credit rating model, we integrated the BFPM and the AHP model using both financial and non-financial information. Finally, the credit ratings of each firm are assigned by our proposed method. This method will be helpful for the loan evaluators of financial institutes to decide more objective and effective credit ratings.

• 한국환경복원기술학회지
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• 제22권6호
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• pp.77-87
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• 2019

The first grade zones in Ecology and Nature Map are important regions for the conservation of the ecosystem, but it would be degraded by various anthropogenic factors. This study analyzes the relationship between potential land cover change and degradation of the first grade zones using land cover transition probability. As a result, it was shown that most of the first grade zones with degraded were converted from forest to urban(5.1%), cropland(27.2%), barren(11.0%) and grass(27.5%) in Gangwon and forest to urban(18.0%), cropland(15.3%), grass(28.4%), barren(12.3%) in Gyeonggi. The result of the logistic regression analysis showed that the probability of degradation of first grade zone was higher in area where was expected the higher probability of urban, cropland, barren, grass transition. The barren transition probability was the most influential and grass was the next highest. There were regional differences in the probability of urban transition and cropland transition, and the urban transition probability was more influential in Gyeonggi-do. This is because development pressure such as housing site development is high in Gyeonggi-do. Due to the limitations of the Act on Mountain Districts Management, even in the first grade zones, the grade may be degraded. Therefore, if Ecology and Nature Map are used to prevent deforestation or conversion of mountainous districts, it may contribute to the preservation of the ecosystem.

• 한국컴퓨터정보학회논문지
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• 제17권11호
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• pp.107-116
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• 2012

본 논문에서는 과거 발생했던 범죄 빈도수가 적용된 해당 지역의 도시 공간 정보를 구성하고 있는 객체를 바탕으로 육안으로 판별이 가능한 특징들을 판독키로 정하고, 위험도를 계량화하였으며, 미래 예측 기법인 마코프 체인 방식을 적용하여 래스터 형태의 위험도 확률지도를 생성하는 기법을 제안한다. 이때 객체 판독키는 일정 크기의 셀로 나누어 셀에 해당하는 계량화된 위험지수를 적용하고, 여러 계층의 범죄 예측 확률지도를 통합하여 통합된 위험도 확률지도를 생성한다. 이는 정적인 정보가 아닌 시간에 따라 위험도 확률지도가 변화될 수 있고, 객체 판독키의 추가 적용에 따라 달라질 수 있는 위험도 확률지도를 생성하여 범죄의 예방에 적용될 수 있는 모델 구성 방법을 제시한 것으로, 순찰 경로 및 감시 장비의 최적 배치에 활용될 수 있을 것이다.

• 한국음향학회지
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• 제43권3호
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• pp.285-292
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• 2024

소나 탐지확률을 계산하는 경우, 수중음향 불확정성은 표준편차가 8 dB ~ 9 dB인 정규분포를 따르는 것으로 고려되고 있다. 하지만, 소나 탐지성능은 실험해역, 해양환경 변동성에 따라 크게 변화하기 때문에 해상실험 데이터 기반의 수중음향 불확정성을 반영한 탐지성능 예측이 필요하다. 본 논문에서는 동해 천해환경에서 측정된 중주파수(2.3 kHz, 3 kHz) 소음준위와 전달손실 자료 기반의 수중음향 불확정성이 산출되었다. 해상실험 데이터 기반의 수중음향 불확정성을 반영한 예상탐지확률을 산출한 후, 이를 기존의 탐지확률 결과, 레일리 분포의 불확정성과 음으로 치우친 분포의 불확정성을 반영한 예상탐지확률 결과와 비교하였다. 결과적으로 각각의 수중음향 불확정성에 따라 탐지영역의 차이가 발생하는 것을 확인할 수 있었다.

• Journal of Preventive Veterinary Medicine
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• 제42권4호
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• pp.163-170
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• 2018

The cost-effectiveness of foot-and-mouth disease (FMD) control strategies was evaluated using a simulation model fitted to the 2010/11 FMD epidemic in the city of Andong, Republic of Korea. Seven FMD-control strategies were evaluated with respect to the direct cost of a FMD-control strategy, such as slaughtering, movement restriction, and vaccination. All the strategies included pre-emptive slaughtering, movement restriction, and vaccination, but the levels of each control option were different. The simulated median cost of the baseline FMD-control strategy (three kilometers of pre-emptive slaughtering area, 100 days of movement restriction and vaccination of all FMD-susceptible animals in the study area) was estimated to be USD 99.7 million. When a five kilometer vaccination area was applied (with the other control measures being the same as the baseline strategy), the simulated median cost was reduced to USD 81.1 million from USD 99.7. The simulated median costs were USD 107.6 million for a five kilometer radius slaughtering area and USD 168.8 million for 60 days of movement restriction. The FMD-control strategy cost decreased with increasing number of farms depopulated per day. The probability of passive surveillance being effective or the probability of the successful implementation of movement restrictions were increased. Cost-effectiveness analysis is a suitable tool for evaluating the financial consequences of FMD-control strategies by comparing the cost of control strategies for a specific area.

• 정보처리학회논문지D
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• 제9D권6호
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• pp.1119-1126
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• 2002

이 논문에서는 공간적 통계기법에 근거한 예측적 공간 데이터 마이닝 방법을 제안하고, 산불위험지역을 예측하는데 적용하였다. 제안된 방법은 조건부 확률과 우도비를 이용한 방법으로 과거 산불발생지역에 대해 산불과 관련된 공간데이터 집합들 사이의 정량적 관계에 의존적인 예측 모델이다. 두 가지 방법을 이용하여 산불위험지역 예측도를 만들고, 각 모델의 예측력을 평가하기 위해 산불위험율(FHR : Forest Fire Hazard Rate)과 예측률곡선(PRC : Prediction Rate Curve)을 이용하였다. 제안된 두 가지 예측모델의 예측력 비교분석 결과, 우도비 방법이 조건부 확률 방법보다 더 우수한 것으로 나타났다. 이 논문에서 제안된 산불위험지역 예측모델을 이용하여 작성된 산불위험지역 예측도는 산불예방과 산불감시장비 및 인력의 효율적인, 배치 등 산불관리의 효율성을 높이는데 많은 도움을 줄 것으로 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.498-500
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• 2009

When we urgently need to develop and supply an alternative energy, wind power is growing with much interest because it has relative low cost for generating power and small area for wind turbine. To estimate the wind power resource, it is necessary to make an observation first. Although the large wind farm and resources are near coast and mountain area, the wind energy in urban area has the strong thing of direct access to power generator. In this study, we estimate the probability of wind energy in urban mountain area using A2C (Atmospheric to CFD) model, which is used for horizontally urban scale phenomena. In the steady state results, the site C is most suitable for wind power in the point of the only wind speed. But, estimating the TKE and vertical wind shear, the site B is showing the better results than the site C.

• 한국ITS학회 논문지
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• 제9권1호
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• pp.91-100
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• 2010

최근 항공교통량의 증가에 따라 보다 효율적인 항공교통흐름제어가 요구되고 있다. 이에 본 논문에서는 효율적인 항공교통흐름제어를 위한 알고리즘을 제안하였다. 항공통신 환경은 일반 통신 환경과는 다르게 스테이션(항공기) 사이에 직접적인 통신 기능이 필요하며, 안전성을 위한 메시지의 우선순위가 매우 엄격하게 요구된다. 게다가 넓은 서비스 지역은 높은 전파지연을 발생시킨다. 본 논문에서는 기존의 CSMA/CA 매체접속제어(MAC) 프로토콜을 사용하여 항공교통상황(혼잡 공항 지역, 접근관제구역, En route구역, 대양 항행)에 따라 메시지 우선순위를 설정하고, 이러한 우선순위가 높은 메시지가 보다 더 높은 접속 확률을 갖고 데이터를 전송하도록 하였다. 항공기 대수에 따른 시뮬레이션 결과, 교통량이 증가할수록 기존 방식보다 더 높은 채널 사용 효율 및 전송확률을 가짐을 확인하였다.