• Journal of Korea Water Resources Association
• /
• v.39 no.6 s.167
• /
• pp.495-502
• /
• 2006

The importance of the bandwidth selection has been more emphasized than the kernel function selection for nonparametric frequency analysis since the interpolation is more reliable than the extrapolation method. However, when the extrapolation method is being applied(i.e. recurrence interval more than the length of data or extreme probabilities such as $200{\sim}500$ years), the selection of the kernel function is as important as the selection of the bandwidth. So far, the existing kernel functions have difficulties for extreme value estimations because the values extrapolated by kernel functions are either too small or too big. This paper suggests a Modified Cauchy kernel function that is suitable for both interpolation and extrapolation as an improvement.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.2
• /
• pp.29-35
• /
• 2011

The behaviors of combustion-induced internal flows of SRM equipped with fin-slot grain and submerged nozzle are very complex and diverse. Cold air-flow tests for 2D and 3D scale models of SRM have been done in order to specify the visualization method to analyze particular internal flow patterns such as roll-torque inducing flow. Swirl flow induced by asymmetric vortical tubes also has been visualized through employing various light source and recording directions.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.4
• /
• pp.343-350
• /
• 2006

For integrating and utilizing the statistical data, which is summarized by arbitrary areal unit such as demographics, with stellite imagery or other GIS data, areal unit of both data should be accorded. Dasymetric mapping is proposed as a useful method fur disaggregating the aggregated statistical data to finer areal unit or generating surface model from object data such as polygonal area. This research evaluate the effectiveness of dasymetric mapping by 1) summarizing the yellow page information by administrative district, 2) modeling the business density using dasymetric mapping, and 3) comparing the business densities of raw data and that of spatial interpolation result.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.181-185
• /
• 2010

The behavior of combustion-induced internal flow of SRM equipped with fin-slot grain and submerged nozzle is very complex and diverse. Cold air-flow test for 2D and 3D scale models of SRM has been done in order to specify the visualization method to analyze particular internal flow patterns such as roll-torque inducing flow. Swirl flow induced by asymmetric vortical tube also has been visualized through employing various light source and recording directions.

• The Korean Journal of Applied Statistics
• /
• v.5 no.2
• /
• pp.113-121
• /
• 1992

Statistical interpolation which uses past experience about the behaviour of the atmosphere(correlation function) to interpolate the observations irregularly distributed in space and time to regular grids is discussed. Correlation functions are computed in the Far East Asian region during the winter periods of December 1977 to February 1980. Results show from the computation of correlation functions that there exists a large difference in the autocorrelation functions by slowly decreasing geopotential height and temperature, and rapidly decreasing wind and mixing ratio with increasing data-correlation functions between geopotential height and wind are well corresponed to persistence of wintertime synoptic features.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.289-289
• /
• 2017

자연 현상을 연구 대상으로 하는 공학적인 접근법이나 과학적인 접근법에 있어서 컴퓨터를 활용한 수치모의는 이제 거의 모든 분야에서 활용되고 있으며, 복잡한 자연 현상을 해석하고 예측하기 위한 필수적인 하나의 도구로 자리매김하고 있다. 하지만, 컴퓨팅 기술의 눈부신 발전에도 불구하고, 과거에 개발되어 현재까지도 활용되고 있는 기술의 보완점은 항상 제기되고 있으며, 또한 필요성에 의한 새로운 기술들이 끊임없이 새롭게 개발되고 있다. 하천 또는 지하수 모의를 위해서 모형을 구축할 때 가장 기본적이며, 가장 중요한 준비 과정은 모의 영역에 대한 격자 형성이다. 연속성을 지닌 모의 대상을 수치적으로 접근하기 위해서는 연속성을 가정한 불연속적인 격자를 생성하는 과정이 반드시 필요하며, 연속성을 지닌 자료로부터 이산적인 자료를 얻어 내삽과정을 통해 격자점에 할당하게 된다. 모의준비 과정뿐만 아니라 모의 결과의 활용과정에서도 내삽이 필요할 수 있다. 따라서, 본 연구에서는 trend-surfaces법, 역거리 가중치법, spline법 등 기존에 알려진 공간자료 보간법들을 지형 자료 또는 지하수위 자료 등의 2차원 공간 자료에 적용하여 비교, 분석하며, 보다 효과적인 내삽기술에 대해서 알아보고자 한다.

• 한국해양학회지
• /
• v.29 no.3
• /
• pp.228-238
• /
• 1994

The change of sea-level is a good indicator of the change of climate during the Quaternary period. The sea-levels in the world have been changing very irregularly during that time. The pattern of the Quaternary sea-level change was assumed to be a stochastic fractal in this study. We measured fractal dimensions of the Holocene sea-levels of the Hudson river estuary and the Delaware coast. A box counting method gave almost the same values. i.e., D=1.358 for the Hudson sea-level changes and D+1.346 for the Delaware sea-level changes. the ability of the inverse method of fractal interposea-levels. IFIF reproduction the realistic sea-levels for the both of them. The delaware sea-level data made less statistical errors for the interpolation of IFIF than the Hudson and the Delaware sea-levels. IFIF reproduction the realistic sea-levels for the both of them. The Delaware sea-level data made less statistical errors for the interpolation of IFIF than the Hudson sea-level data. This suggests that the Delaware sea-level data are more reliable than the Hudson sea-level data was calculated from the fractal dimension of the Delaware sea-level data. Fractal interpolation functions (FIF) was used to reconstruct the peleosea-levels of the Korean coasts and the Atlantic Ocean coasts of the United States. The Korean Peleosea-level change generacted by FIF is different from the peleosea-level change of the eastern U.S.. The Korean peleosea-levels are much higher than the eastern U.S. Paleosea-levels, comparing to each other from the present to 8,000 BP.

• The Bulletin of The Korean Astronomical Society
• /
• v.25 no.2
• /
• pp.57-57
• /
• 2000

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1992.06a
• /
• pp.39-42
• /
• 1992

• Bulletin of the Korean Space Science Society
• /
• 2000.10a
• /
• pp.57-57
• /
• 2000