• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.365-368
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• 2022

본 논문에서는 가상 물체를 현실과 오차 없이 정확하게 증강 시켜야 하는 상황에서 특징 포인트를 이용하여 효율적으로 매칭하기 위한 실린더 기반의 각도 보간 기법을 제안한다. 증강현실에서 활용되는 대표적인 객체를 증강하는 방법은 특징 포인트들을 트래킹하여 찾아낸 후, RANSAC 알고리즘을 기반으로 포인트 셋에서 바닥, 벽과 같이 하나의 평면을 구성하고 그 위에 객체를 증강한다. 이 방법은 평면을 이용하기 때문에 계산량이 적지만, 증강 위치에 대한 오차가 존재하기 때문에 때때로 잘못된 위치에 객체가 배치되는 경우가 발생한다. 특히, 의료시설, 도로 공사에서 증강 현실을 사용했을 때에 증강된 가상물체의 위치, 크기 등이 현실에서 작은 오차라도 어긋날 경우 크게 사고가 발생할 수 있다. 본 논문에서는 평면 생성 없이 특징 포인트만을 이용하여 효율적으로 매칭 할 수 있는 실린더 기반의 각도 보간을 이용하여 정확하게 객체를 증강할 수 있는 결과를 보여준다.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.219-227
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• 2012

Daily solar radiation is essential for water resources planning and environmental impact assessment. However, radiation data is not commonly available in Korea other than in big cities, and there has been no direct measurement for rural areas where water resources planning and environmental impact assessment is usually most needed. In general, missing radiation data is estimated from nearby regional stations within a certain distance, and this study compared two dominant methods (modified Angstrom equation and transmittance interpolation method) at six stations in Nakdong River watershed area. Two methods shows a similar level of accuracy but the transmittance interpolation method is likely to be superior in that there is no need for any measurement element since the modified Angstrom equation require the sunshine hour measurement. This study will contribute to improve water resource and water quality management in Nakdong River watershed.

• Journal of Web Engineering
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• v.20 no.8
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• pp.2413-2432
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• 2021

Recently, the demand for high-quality video content has rapidly been increasing, led by the development of network technology and the growth in video streaming platforms. In particular, displays with a high refresh rate, such as 120 Hz, have become popular. However, the visual quality is only enhanced if the video stream is produced at the same high frame rate. For the high quality, conventional videos with a low frame rate should be converted into a high frame rate in real time. This paper introduces a bidirectional intermediate flow estimation method for real-time video frame interpolation. A bidirectional intermediate optical flow is directly estimated to predict an accurate intermediate frame. For real-time processing, multiple frames are interpolated with a single intermediate optical flow and parts of the network are implemented in 16-bit floating-point precision. Perceptual loss is also applied to improve the cognitive performance of the interpolated frames. The experimental results showed a high prediction accuracy of 35.54 dB on the Vimeo90K triplet benchmark dataset. The interpolation speed of 84 fps was achieved for 480p resolution.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.7-10
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• 2008

We present a technique for constructing a digital elevation model (DEM) from contours. The elevation of each ground point in DEM is computed by interpolating the heights of the two adjacent contours of the point. The technique decomposes each sub-domain between adjacent contours into a set of sub-regions. The decomposition is accomplished by constructing a medial axis of the sub-domain. Each sub-region in the decomposition is classified into a variety of terrain features like hillsides, valleys, ridges, etc. The elevations of points are interpolated with different methods according to terrain features they belong to. For a given point in hillside, an approximate gradient line passing through the point is determined and the elevation of the point is interpolated from the known elevations of the two adjacent contours along the approximate gradient line. The univariate monotone rational Hermite spline is used for the interpolation. The DEM constructed by the technique is to be used to orthorectify the high-resolution KOMPSAT3 imagery.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.473-485
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• 2019

In this study, we investigated the differences of graph constructed by middle school students in daily-life and scientific contexts according to the views on the nature of scientific measurement. A test consisting of three similar data sets regarding daily-life and scientific contexts was developed, and administered to 151 ninth graders. They were expected to construct proportional, inverse-proportional, and increasing and become constant form of graphs for each data set. Graphs constructed were analyzed in the aspects of constructing a trend line (types of a trend line, interpolation/extrapolation), selecting axes variables, scaling axes, and plotting points. Analyses of the results revealed that the students with set paradigm tended to construct a curved trend line, while those with point paradigm constructed a broken trend line in inverse-proportional graph questions. In the aspects of interpolation/extrapolation, most students with set paradigm performed both interpolation and extrapolation better than those with point paradigm in scientific context. Most students with set paradigm performed both interpolation and extrapolation regardless of contexts, while the proportion of interpolation of those with point paradigm was higher in scientific context than in daily-life context. In selecting axes variables, scaling axes, and plotting dots, there were no statistically significant differences between set and point paradigms. On the bases of the results, educational implications for improving graph construction skills of middle school students are discussed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.543-550
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• 2011

The gravity anomaly is a basic geophysical data applied in various fields such as geophysics, geodesy and national defense. In general, the gravity anomaly is used through a interpolation process based on the constructed database. The gravity variation, however, is appeared in various shapes depending on the topography and the density of the underground structures. Therefore, the interpolation could lead to a large differences if the gravity fields do not satisfy the assumptions on the signal behavior like linear or a certain degree polynomials. Furthermore, the interpolation does not reflect the physical characteristics of the gravity such as the harmonic condition. In this study, the gravity modeling using the plane Fourier series and radial basis functions are performed to overcome the problems in the usual interpolation. The results of the modeling is analyzed for the case of the gravity referenced navigation focused on the signal characteristics. Based on the study, it was found that the results from modeling are not much different to that from the interpolation in a smoothly varied area. In case of the highly varied area, however, a large differences are appeared among the three methods. Especially, the Fourier series shows the most smooth variations in the modeled gravity values while the highest variations appeared in the interpolation. Applying to the gravity referenced navigation, it was found that the modeling is more effective in calculation cost. It is considered that the results from this study provides a basis on effective modeling of the gravity fields in terms of the signal characteristics and resolution for various application fields.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3690-3713
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• 2019

According to the main group key management schemes logical key hierarchy (LKH), exclusion basis systems (EBS) and other group key schemes are limited in network structure, collusion attack, high energy consumption, and the single point of failure, this paper presents a group key management scheme for wireless sensor networks based on Lagrange interpolation polynomial characteristic (AGKMS). That Chinese remainder theorem is turned into a Lagrange interpolation polynomial based on the function property of Chinese remainder theorem firstly. And then the base station (BS) generates a Lagrange interpolation polynomial function f(x) and turns it to be a mix-function f(x)' based on the key information m(i) of node i. In the end, node i can obtain the group key K by receiving the message f(m(i))' from the cluster head node j. The analysis results of safety performance show that AGKMS has good network security, key independence, anti-capture, low storage cost, low computation cost, and good scalability.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.8
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• pp.251-260
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• 2014

3D point data is utilized in various industry domains for its high accuracy to the surface information of an object. It is substantially utilized in geography for terrain scanning and analysis. Generally, 3D point data need to be changed by Gridding which produces a regularly spaced array of z values from irregularly spaced xyz data. But it requires long processing time and high resource cost to interpolate grid coordination. Kriging interpolation in Gridding has attracted because Kriging interpolation has more accuracy than other methods. However it haven't been used frequently since a processing is complex and slow. In this paper, we presented a parallel Gridding algorithm which contains Kriging and an application of grid data structure to fit MapReduce paradigm to this algorithm. Experiment was conducted for 1.6 and 4.3 billions of points from Airborne LiDAR files using our proposed MapReduce structure and the results show that the total execution time is decreased more than three times to the convention sequential program on three heterogenous clusters.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.2
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• pp.94-104
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• 2002

As a part of scientific data visualization automatic generation algorithms for a contour map have been investigated mainly on data which are defined at every lattice point. But in actual situation like weather data measurement. it is impossible to get data defined at every lattice point This is because the exact value on every lattice point can not be obtained due to characteristics in sampling devices or sampling methods. In order to define data on every lattice point where data were not sampled an interpolation method. was applied to the sample data to assign approximate values for some lattice type data but by using the non-lattice type of sample data sets. A triangle data link was defined by using non lattice points directly based on actually sample data set, not by using the pre-processed rectangle lattice points. The suggested algorithm generates a contour map a contour map only by using sample data set which are much smaller than old one without data interpolation and there is no skew on data any more since it does not need any interpolation to get the values of the defined lattice points.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.427-427
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• 2015

The storm water management and drainage relation are the key variable that plays a vital role on hydrological design and risk analysis. These require knowledge about spatial variability over a specified area. Generally, design rainfall values are expressed from the fixed point rainfall, which is depth at a specific location. Concurrently, determine the areal rainfall amount is also very important. Therefore, a spatial rainfall interpolation (point rainfall converting to areal rainfall) can be solved by areal reduction factor (ARF) estimation. In mainland of South Korea, for dam design and its operation, public safety, other surface water projects concerned about ARF for extreme hydrological events. In spite of the long term average rainfall (2,061 mm) and increasing extreme rainfall events, ARF estimation is also essential for Jeju Island's water control structures. To meet up this purpose, five fixed rainfall stations of automatic weather stations (AWS) near the "Hancheon Stream Watershed" area has been considered and more than 50 years of high quality rainfall data have been analyzed for estimating design rainfall. The relationship approach for the 24 hour design storm is assessed based on ARF. Furthermore, this presentation will provide an outline of ARF standards that can be used to assist the decision makers and water resources engineers for other streams of Jeju Island.