• 한국군사과학기술학회지
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• 제9권1호
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• pp.99-108
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• 2006

In this paper, we analyzed the characteristics of emitter geolocation coverage area within which the emitter lies with a specified probability based on the LOBs(Line of Bearing) of sensors. Stansfield and MSD algorithms were applied to calculate BPE(Best Point Estimate), EEP(Elliptical Error Probable) and CEP(Circular Error Probable), They used the weighting factors composed of ${\sigma}_{Phi}$ (bearing error), QF(quality factor), $P_{e}$ (probability being inside) to optimize the performance. The characteristics of EEP was investigated in the change of them and those of CEP was analyzed based on the deployment of sensors.

• Journal of applied mathematics & informatics
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• 제13권1_2호
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• pp.501-508
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• 2003

Although the estimate of regression function is important, some have focused the variance estimation of error term in regression model. Different variance estimators perform well under different conditions. In many practical situations, it is rather hard to assess which conditions are approximately satisfied so as to identify the best variance estimator for the given data. In this article, we suggest SHM estimator compared to LS estimator, which is common estimator using in parametric multiple regression analysis. Moreover, a combined estimator of variance, VEM, is suggested. In the simulation study it is shown that VEM performs well in practice.

• International Journal of Reliability and Applications
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• 제7권2호
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• pp.187-201
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• 2006

In this paper, we derive recurrence relations for the single and product moments of progressively Type-II right censored order statistics from half logistic distribution. Next, we derive the maximum likelihood estimators (MLEs) of the location and scale parameters of the half logistic distribution. In addition, we use the setup proposed by Balakrishnan and Aggarwala (2000) to compute the approximate best linear unbiased estimates (ABLUEs) of the location and scale parameters. Finally, we point out a simulation study to compare between the efficiency of the techniques considered for the estimation.

• Nuclear Engineering and Technology
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• 제18권3호
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• pp.175-182
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• 1986

원자력 1호기의 설계 기준 사고인 외부 전원 상실 사고를 열, 수력학적 최적 계산용 코드인 RELAP5/MOD1/NSC를 사용하여 모의하였다. 본 분석은 최적 계산모델로 수행되었으나, 사고 전개 및 가정등 보수성을 갖는 평가 방법에 의거하였다. 해석결과중 노심평균온도, 증기발생기 및 가압기 수위 등의 중요한 열·수력학적 변수를 원자력 1호기의 최종 안전성 분석보고서의 결과와 비교하였다. 본 해석결과에서 노심평균온도와 가압기 수위는 보다 낮게, 증기발생기 수위는 보다 높게 나타남으로써 더 향상된 안전한계치를 확인하였다. 이것은 본 해석에서 최적 열·수력 모델을 사용하였을 뿐만 아니라 초기치로써 최적 값을 택하였기 때문에 얻어지는 결과이며, 또한 이와 같은 유형의 산고 (2차 계통의 열제거 능력 상실 사고)에서 원자력 1호기의 안전성을 더욱더 입증시켜 주는 것이다.

• International Journal of CAD/CAM
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• 제5권1호
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• pp.19-27
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• 2005

As three-dimensional range scanners make large point clouds a more common initial representation of real world objects, a need arises for algorithms that can efficiently process point sets. In this paper, we present a method for extracting smooth surfaces from dense point clouds. Given an unorganized set of points in space as input, our algorithm first uses principal component analysis to estimate the surface variation at each point. After defining conditions for determining the geometric compatibility of a point and a surface, we examine the points in order of increasing surface variation to find points whose neighborhoods can be closely approximated by a single surface. These neighborhoods become seed regions for region growing. The region growing step clusters points that are geometrically compatible with the approximating surface and refines the surface as the region grows to obtain the best approximation of the largest number of points. When no more points can be added to a region, the algorithm stores the extracted surface. Our algorithm works quickly with little user interaction and requires a fraction of the memory needed for a standard mesh data structure. To demonstrate its usefulness, we show results on large point clouds acquired from real-world objects.

• Nuclear Engineering and Technology
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• 제39권5호
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• pp.591-602
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• 2007

The results of Reactivity-Initiated Accidents (RIA) experiments have been analysed and the main variables affecting the fuel failure propensity identified. Fuel burn-up aggravates the mechanical loading of the cladding, while corrosion, or better the hydrogen absorbed in the cladding as a consequence of corrosion, may under some conditions make the cladding brittle and more susceptible to failure. Experiments point out that corrosion impairs the fuel resistance for RIA transient occurring at cold conditions, whereas there is no evidence of important embrittlement effects at hot conditions, unless the cladding was degraded by oxide spalling. A fuel failure threshold correlation has been derived and compared with experimental data relevant for BWR and PWR fuel. The correlation can be applied to both cold and hot RIA transients, account taken for the lower ductility at cold conditions and for the different initial enthalpy. It can also be used for non-zero power transients, provided that a term accounting for the start-up power is incorporated. The proposed threshold is easy to use and reproduces the results obtained in the CABRI and NSRR tests in a rather satisfactory manner. The behaviour of advanced PWR alloys and of MOX fuel is discussed in light of the correlation predictions. Finally, a probabilistic approach has been developed in order to account for the small scatter of the failure predictions. This approach completes the RIA failure assessment in that after determining a best estimate failure threshold, a failure probability is inferred based on the spreading of data around the calculated best estimate value.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.51-54
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• 2000

We are concerned with processing methods of the measurement values of sensors in the control system. When some faults happen to sensor components, the measurement value of sensors cause the malfunction of the plant. So it is necessary to detect and reduce the influence of faults to control with reliability for the overall system. The sensor status must be always good for best demonstration of the controller performance. A self-validating sensor detects the sensor state from the measurement value, reconstruct a soft sensor and can improve reliability of the sensor. If sensor faults, the sensor is detected and reconstructed with the best estimate from its correlation to other sensors and historical data. It is applied to the control of a flexible link system with the sensor fault problems in the light sensor module for position to show the applicability. In this paper, we propose a digital controller which reduces deflection of the moving set-point by reconstructing output of a sensor when the sensor fault is detected.

• 환경영향평가
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• 제23권2호
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• pp.88-100
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• 2014

This study analyzed runoff characteristics of non-point sources pollutant and evaluated removal of pollution by BMP(Best Management Practice) using BASINS/WinHSPF model. Hourly meterological data including input data was provided from 2010 to 2011 year to run HSPF model in Miho stream watershed. As the results of calibration and validation of the model, the model could be successfully performed to simulate the flow and water quality parameters. The apprehensive area of non-point source pollution was chosen by non-point source pollution per area of a tributary to the Miho stream and applied constructed wetland in area chosen. Three scenarios were based on installation area of an constructed wetland and HSPF model would be applied to estimate the pollutant removals through the constructed wetland. The removal rates of pollutants through the constructed wetland were estimated with the runoff and water quality parameters by the comparisons of before and after the constructed wetland application.

• 한국컴퓨터산업학회논문지
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• 제4권12호
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• pp.1043-1052
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• 2003

본 논문에서는 비디오코딩의 움직임 추정을 위한 빠른 움직임 추정알고리즘을 제안하였다. 제안된 알고리즘은 다단계 연속제거 알고리즘과 효율적인 다단계 연속제거 알고리즘에 기초하고 있다. 제안된 알고리즘은 계층적으로 탐색점을 추출하여 매우 많은 연산량을 필요로 하는 정합 연산량을 감소시키면서 최상의 움직임벡터를 얻을 수 있다. 실험을 통하여 제안된 알고리즘의 효율성을 확인하였다.

• 환경영향평가
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• 제18권1호
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• pp.31-39
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• 2009

A lot of data which are used in environment analysis of air pollution have characteristics that are distributed continuously in space. In this point, the collected data value such as precipitation, temperature, altitude, pollution density, PM10 have spatial aspect. When geostatistical data analysis are needed, acquisition of the value in every point is the best way, however, it is impossible because of the costs and time. Therefore, it is necessary to estimate the unknown values at unsampled locations based on observations. In this study, spatial interpolation method such as local trend surface model, IDW(inverse distance weighted), RBF(radial basis function), Kriging were applied to PM10 annual average concentration of Seoul in 2005 and the accuracy was evaluated. For evaluation of interpolation accuracy, range of estimated value, RMSE, average error were analyzed with observation data. The Kriging and RBF methods had the higher accuracy than others.