• Proceedings of the Korean Information Science Society Conference
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• 2008.06b
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• pp.588-591
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• 2008

본 논문은 Data mining에서 선호도 분석 등에 사용되는 Skyline Query[2] 중 자료의 속성에 spatial한 성질이 있을 때 사용할 수 있는 Spatial Skyline Query[3] 문제에 대해 연구한다. 우선 Spatial Skyline 집합을 추출하기 위한 기존의 알고리즘의 문제점을 짚어보고 보다 개선된 알고리즘을 제시한다. 또한 전체 Spatial Skyline 집합이 아닌 그 중 더 의미 있을 수 있는 부분 집합을 좀 더 빠른 시간 복잡도에 구하는 방법 또한 제시한다.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.137-143
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• 2004

다양한 지형공간과 시설물이 공존하는 대학캠퍼스를 입체적으로 보여주고 그 시설물을 관리하기 위해서는 2차원 평면적 요소와 결합된 3차원 이상의 공간정보의 생성은 매우 중요한 캠퍼스 관리의 선택요소로 등장하고 있다. 이를 위하여 현재 사용가능한 지형도와 시설도 및 영상자료를 정확한 위치정보로 추출 또는 변환하여 지형공간 내에 존재하는 도로, 건물, 기타 시설물을 입체적으로 중첩함으로서 3차원 이상의 입체적 효과는 물론 부분적으로는 이동접근이 가능한 시뮬레이션 작업을 적용하였다.

• Journal of Korea Water Resources Association
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• v.43 no.8
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• pp.733-745
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• 2010

Seasonality of hydrologic extreme variable is a significant element from a water resources managemental point of view. It is closely related with various fields such as dam operation, flood control, irrigation water management, and so on. Hydrological frequency analysis conjunction with partial duration series rather than block maxima, offers benefits that include data expansion, analysis of seasonality and occurrence. In this study, nonstationary frequency analysis based on the Bayesian model has been suggested which effectively linked with advantage of POT (peaks over threshold) analysis that contains seasonality information. A selected threshold that the value of upper 98% among the 24 hours duration rainfall was applied to extract POT series at Seoul station, and goodness-fit-test of selected GEV distribution has been examined through graphical representation. Seasonal variation of location and scale parameter ($\mu$ and $\sigma$) of GEV distribution were represented by Fourier series, and the posterior distributions were estimated by Bayesian Markov Chain Monte Carlo simulation. The design rainfall estimated by GEV quantile function and derived posterior distribution for the Fourier coefficients, were illustrated with a wide range of return periods. The nonstationary frequency analysis considering seasonality can reasonably reproduce underlying extreme distribution and simultaneously provide a full annual cycle of the design rainfall as well.

• Journal of Information Technology Application
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• v.1 no.3_4
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• pp.69-90
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• 1999

본 논문은 시계열자료의 ARMA 모형화를 위해 계층적(Hierarchical) 문제해결 방식인 인공신경망 기초 의상결정트리분류기상의 인공신경망 구조를 개선하여 지역문제(Local Problem)를 해결하는 복수개의 인공신경망 결과를 Dempster's rule of combination을 이용하여 종합하는 병행적인 (Parallel) ARMA 모형활르 위한 방법론을 제시함으로써 의사결정트리분류기에 근거한 방법론의 단점을 보완하였다. 본 논문에서 제시한 ARMA 모형화를 위한 방법론은 세 단계로 구성되어 있다: 1) ESACF 특성 벡터 추출단계; 2) 개별 인공신경망에 의한 부분적 모델링 단계; 3) Conflict Resolution 단계, 제시한 방법론을 검증하기 위해 모의실험용 자료와 실제 시계열자료를 이용하여 제시된 방법론을 검증하였으며 실험결과 기존 연구에 비해 ARMA 모형화와 정확도가 높은 것으로 나타났다.

• Journal of Digital Contents Society
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• v.7 no.1
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• pp.53-58
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• 2006

In this paper, We proposed extraction method using EZW a specific character and then add watermark significant coefficient of image. After wavelet transform in image, the significant coefficient value add to watermark information image. In this method, the locations of nonzero wavelet coefficients are encoded with a tree structure, called zerotree, which can exploit the self-similarity of the pyramid decomposition across different scales. The simulation shows that this method provides a superior performance over conventional method and can be successfully applied to the application areas that requires of progressive transmission and search for image data.

• Korean journal of applied entomology
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• v.54 no.3
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• pp.159-167
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• 2015

In order to establish B. tabaci control in paprika greenhouses a fixed-precision-level sampling plan was developed. The sampling plan consisted of spatial distribution analysis, a sampling stop line, and decision making. Sampling was conducted simultaneously in two independent greenhouses (GH 1, GH 2). GH 1 and 2 were surveyed every week for 22 consecutive weeks, using 19 sampling locations in GH 1 and 9 sampling locations in GH 2. The plant in both greenhouses were divided into top (180-220 cm from the ground), middle (80-120 cm from the ground) and bottom (30-70 cm from the ground) sections and B. tabaci adults and pupae were observed on three paprika leaves at each position and recorded separately. GH 2 data were used to validate the fixed-precision sampling plan, which was developed using GH 1 data. In this study, spatial distribution analysis was performed using Taylor's power law with the pooled data of the top and bottom position (B. tabaci adults), and the middle and bottom positions (B. tabaci pupae), based on a 1-leaf sampling unit. Decision making was undertaken using the maximum of action threshold in accordance with previously published method, and the value was decided by the price of the plants. Using the results obtained in the greenhouse, simulated validation of the developed sampling plan by RVSP (Resampling Validation for Sampling Plan) indicated a reasonable level of precision.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.274-277
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• 2011

기후변화는 전 세계적으로 많은 관심을 얻고 있으며 그로 인한 재산과 인명피해의 증가가 우려되고 있다. 기후변화에 대해 가장 취약한 부분은 수자원분야이며 수자원 활용의 극대화를 위하여 여러 예측방법이 활용되고 있다. 본 연구에서는 기상변화의 예측 및 모델링 기법 중 하나와 수문모델의 융합 기법을 활용하였다. 선행 연구에서는 레이더 강우자료와 지상 우량계의 강우자료로 여유추정시간에 대한 단기 예측만이 가능하게 하였는데 이 방법은 조금 더 여유 추정시간을 증가 시키는 장점이 있다. 이 연구에서는 여유추정시간의 증가에 대한 정확성을 검증하기 위하여 청미천 유역을 대상으로 연구를 실시하였다. 연구 방법으로는 ArcGIS와 Arc-View을 사용하여 대상유역의 Curve Number (CN) 값을 추출하고, 강우예측모형인 Weather Research Forecast (WRF) - Advanced Research WRF (ARW) 결과자료와 과거 강우자료의 비교 검증을 통하여 모형의 적용성을 평가하였다. 두 자료는 HEC-HMS의 입력자료가 되며, 이를 바탕으로 지역 유출량 산정 및 지표면 유출 모의를 통한 강우-유출현상을 검토 자료로 활용할 수 있다. 본 연구를 바탕으로 청미천 유역 지표면에서의 강우-유출모의를 개선하여 대상유역의 현상을 보다 유사하게 나타내고자 하였으며, 이와 함께 WRF-ARW 모형을 통하여 여유추정시간의 증가를 모색하고 지역강우 모형이 대한민국 지형의 잘 어울리는 최적화된 매개변수들의 조합을 알아내고 그의 적용현실성을 평가하고자 한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.593-599
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• 2011

With increasing user applicability of geospatial data, user demand for manifold and accurate information has increased. The usefulness of these services derives from their combination of the advantages of as-built geospatial data in making new content. There is a spatial inconsistency and shape disagreement in fusing heterogeneous data. Conflation, defined as the combining of information from diverse sources so as to reconcile spatial inconsistencies and shape disagreement, is possible solution to the problem. In this research, we developed the technique for removing shape disagreement between aerial image and road map removed spatial inconsistency in advanced research. The process includes four processes: producing of a road candidate image, extraction of vertices, and generation of a graph by connecting the vertices. We could remove the shape disagreement using the extracted road that was derived from finding the road possible path.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.2 s.29
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• pp.61-66
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• 2004

By the advent of the high-resolution Satellite imagery, there are increasing needs in image mosaicking technology which can be applied to various application fields such as GIS(Geographic Information system). To mosaic images, various methods such as image matching and histogram modification are needed. In this study, automated image mosaicking is performed using image matching method based on the multi-resolution wavelet analysis(MWA). Specifically, both area based and feature based matching method are embedded in the multi-resolution wavelet analysis to construct seam line.; seam points are extracted then polygon clipping method are applied to define overlapped area of two adjoining images. Before mosaicking, radiometric correction is proceeded by using histogram matching method. As a result, mosaicking area is automatically extracted by using polygon clipping method. Also, seamless image is acquired using multi-resolution wavelet analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.535-540
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• 2006

This paper presented an effective strategy to extract the buildings and to reconstruct 3-D buildings using high-resolution multispectral stereo satellite images. Proposed scheme contained three major steps: building enhancement and segmentation using both BDT (Background Discriminant Transformation) and ISODATA algorithm, conjugate building identification using the object matching with Hausdorff distance and color indexing, and 3-D building reconstruction using photogrammetric techniques. IKONOS multispectral stereo images were used to evaluate the scheme. As a result, the BDT technique was verified as an effective tool for enhancing building areas since BDT suppressed the dominance of background to enhance the building as a non-background. In building recognition, color information itself was not enough to identify the conjugate building pairs since most buildings are composed of similar materials such as concrete. When both Hausdorff distance for edge information and color indexing for color information were combined, most segmented buildings in the stereo images were correctly identified. Finally, 3-D building models were successfully generated using the space intersection by the forward RFM (Rational Function Model).