• 한국지능시스템학회논문지
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• 제22권2호
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• pp.253-260
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• 2012

원거리의 표적을 탐지하기 위한 IRST시스템에서 표적은 배경영역에 포함된 많은 클러터로 인하여 검출이 매우 어렵다. 특히 해상 환경에서 획득된 영상의 경우, 불균일한 해수면 온도 분포는 원거리에서 접근하는 소형 표적의 검출을 어렵게 하는 요인으로 작용한다. 이에 본 논문에서는 형태학적 연산을 기반으로 하는 불균일한 해수면 온도 분포를 추정하는 알고리즘을 제안한다. 정확한 해수면 온도 분포 추정을 위하여 상한 분포와 하한 분포로 나누어 추정하고, 추정된 결과의 평균값으로 최종 해수면 온도 분포를 도출한다. 또한 형태학적 연산을 적용함으로써 발생하는 서브샘플링 효과 문제를 해결하기 위하여 다양한 크기의 구조요소를 이용하는 다중 가중치(multi-weight) 기법을 적용한다. 제안 방법의 타당성을 검증하기 위하여 다양한 환경에서 획득된 해수면 영상에 대한 해수면 온도 분포 추정 결과를 기존 알고리즘과 비교 검증하였다.

• Journal of the Korean Data and Information Science Society
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• 제27권5호
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• pp.1155-1168
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• 2016

기상 자료의 경우 한 지역의 기후가 인접지역의 기후와 비슷한 양상을 띄고 각 지역의 확률 밀도 함수 (probability density function)가 잘 알려진 확률 모형을 따르지 않는다는 것이 알려져 있다. 본 논문에서는 이러한 특성을 고려하여 이상 기후 현상이 뚜렷히 나타나는 여름철 평균 극한 기온(extreme temperature)의 확률 밀도 함수를 추정하고자 한다. 이를 위하여 공간적 상관관계 (spatial correlation)를 고려하는 비모수 베이지안 (nonparametric Bayesian) 모형인 조건부 자기회귀 종추출 혼합모형 (mixtures of conditional autoregression species sampling model)을 이용하였다. 자료는 이스트앵글리아 대학교 (University of East Anglia)에서 제공하는 전 지구의 최대 기온과 최소 기온자료 중 우리나라에 해당하는 지역의 자료를 사용하였다.

• Journal of applied mathematics & informatics
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• 제9권2호
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• pp.771-785
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• 2002

Many industries like energy, utilities, ice cream and leisure sports are closely related to the weather. In order to hedge weather related risks, they invest their assets with portfolios like option, coupons, future, and other weather derivatives. Among weather related derivatives, CDD and HDD index options are mainly transacted between companies. In this paper, the autocorrelation system of temperature will be checked for several cities in Korea and the parameter estimation will be carried based on the maximum likelihood estimation. Since the log likelihood increase as the number of parameters increases, we adopt the Schwarz information criterion .

• 설비공학논문집
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• 제11권1호
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• pp.125-132
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• 1999

Studies are being done to replace conventional refrigerants with alternatives that have low or no ozone depletion and greenhouse warming Potentials, yet possess appropriate pro perties for a refrigeration cycle. To achieve this goal, a consistent set of thermodynamic properties of the working fluid is required. A common problem with the possible alternative refrigerants is that sufficient experimental data do not exist, thus making it difficult to develp complete equations of state that can predict properties in all regions including the vapor-liquid equilibrium. One solution is the use of the generalized equation of state correlations that can predict thermodynamic properties with a minimum number of characteristic parameters. Characteristic parameters required for the generalized equation of state are, in general, critical temperature, critical pressure, critical volume and normal boiling temperature. In this study, estimation of these characteristic parameters of refrigerants by group contribution method is developed.

• 대한원격탐사학회지
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• 제19권5호
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• pp.341-349
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• 2003

The so-called B-method, a simplified surface energy budget, permits calculation of daily actual evapotranspiration (ET) using remotely sensed data, such as NOAA-AVHRR. Even if the use of satellite data allows estimation of the albedo and surface temperature, this model requires meteorological data measured at ground-level to obtain the other inputs. In addition, a difficulty may be occurred by the difference of temporal scales between the net radiation in daily scale and instantaneous measurement at midday of the surface and air temperatures because the data covered whole day are necessary to obtain accumulated daily net radiation. In order to solve these problems, this study attempted a modification of B-method through an extension of hourly ET value calculated using a complete instantaneous inputs. The estimation of the daily apparent ET from newly proposed system showed a root mean square error of 0.26 mm/day as compared the output obtained from the classical model. It is evident that this may offer more rapid estimation and reduced data volume.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.934-939
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• 1998

This study discusses the results of adiabatic temperature rise tests which were performed considering various parameters, such as cement type, water-cement ratio, unit cement weigh, admixtures and placing temperature, which influence the temperature rise(K) and reaction velocity ($\alpha$). Theadiabatic temperature rise models obtained from this study are similar to those of Japan Concrete Institute. The models to calculate temperature rise and reaction velocity could be used the analysis f concrete thermal stress.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2003년도 공동 춘계학술대회 논문집
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• pp.291-296
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• 2003

This study estimated surface temperature by using split-window technique and NOAA/AVHRR data was used. For surface monitoring, cloud masking procedure was carried out using threshold algorithm. The daily maximum air temperature is estimated by multiple regression method using independent variables such as satellite-derived surface temperature, EDD, and latitude. When the EDD data added, the highest correlation shown. This indicates that EDD data is the necessary element for estimation of the daily maximum air temperature. We derived correlation and experience equation by three approaching method to estimate daily maximum air temperature. 1) non-considering landcover method as season, 2) considering landcover method as season, and 3) just method as landcover. The last approaching method shows the highest correlation. So cross-validation procedure was used in third method for validation of the estimated value. For all landcover type 5, the results using the cross-validation procedure show reasonable agreement with measured values(slope=0.97, intercept=-0.30, R$^2$=0.84, RMSE=4.24$^{\circ}C$). Also, for all landcover type 7, the results using the cross-validation procedure show reasonable agreement with measured values(slope=0.993, Intercept=0.062, R$^2$=0.84, RMSE=4.43$^{\circ}C$).

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.47-51
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• 2005

Using satellite images, an optimal solution to water motion has been presented in this study. Since temperature patterns are suitable tracers in water motion, Sea Surface Temperature (SST) images of Caspian Sea taken by MODIS sensor on board Terra satellite have been used in this study. Two daily SST images with 24 hours time interval are used as input data. Computation of templates correspondence between pairs of images is crucial within motion algorithms using non-rigid body objects. Image matching methods have been applied to estimate water body motion within the two SST images. The least squares matching technique, as a flexible technique for most data matching problems, offers an optimal spatial solution for the motion estimation. The algorithm allows for simultaneous local radiometric correction and local geometrical image orientation estimation. Actually, the correspondence between the two image templates is modeled both geometrically and radiometrically. Geometric component of the model includes six geometric transformation parameters and radiometric component of the model includes two radiometric transformation parameters. Using the algorithm, the parameters are automatically corrected, optimized and assessed iteratively by the least squares algorithm. The method used in this study, has presented more efficient and robust solution compared to the traditional motion estimation schemes.

• 한국환경과학회지
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• 제5권5호
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• pp.657-662
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• 1996

여름과 겨울철에 준건조 유역들 (Lucky Hills and Kendall)로부터 측정되어진 기상학적 그리고 flux data를 이용하여 증발산 산정을 위한 변수들의 민감도를 연구하였다. 상대적 민감도 분석을 이용하여 Pen농an의 잠재증발산 산정에 필요한 네 가지 기상학적 그리고 flux변수(순방사, 풍속, 공기온도 그리고 상대습도)들의 중요도가 검증되어졌다. 두 다른 유역으로부터의 연구 결과에 의하면, 여름철에 Pen-mim의 잠재증발산략의 변화는 공기 온도와 순방사에 의해서 지배되어지고, 겨울철에는 상대습도와 공기온도에 의해서 지배되어지는 것으로 나타났다.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.215-221
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• 2010

This paper introduces development of location estimation and navigation system of mobile robots using USN and LEGO Mindstorms NXT. Developed system includes location estimation, location and navigation information display and navigation control parts. It used ZigBee based USN which was built with CC2431 chip to locate blind node and implemented fuzzy model to improve ability of calculation of distances from reference nodes and location of mobile robots. This paper proposed combination method of location estimation using USN and encoder which is built in motors of mobile robots. Experimental results showed proposed method is superior to the method which used USN only in location estimation and navigating robots. Developed system can locate current position of mobile robots and monitor information from sensor nodes like temperature, humidity and send control signal to mobile robot to move.