• Journal of KIISE:Computer Systems and Theory
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• v.27 no.11
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• pp.890-898
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• 2000

본 논문에서는 단순 다각형을 대상으로 하는 형태 변환 알고리즘을 제안한다. 주어진 다각형을 삼각 분할하고 그 듀얼 트리로부터 구성된 듀얼 루트 트리를 이용하여 형태 변환을 유도하는 기하학적인 방법이다. 이 방법은 기존의 알고리즘이 수학적인 모델링을 기반으로 하기 때문에 감수해야했던 많은 양의 함수계산을 피할 수 있으며 다각형의 속성을 유지하는 삼각 분할을 사용함으로써 중간 단계에 생성된 다각형들이 언제나 적합한 형태의 다각형이 될 수 있다는 특징을 갖는다. 이러한 작업이 가능하도록 하기 위해서 본 논문에서는 유사 삼각 분할(similar triangulation)과 유사 트리의 개념을 이용하였다.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.10 no.6
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• pp.15-27
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• 1992

• Communications for Statistical Applications and Methods
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• v.15 no.4
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• pp.551-562
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• 2008

The loss reserve is defined as a provision for an insurer's liability for claims or an insurer's estimate of the amount an individual claim will ultimately cost. For the estimation of the loss reserve, the data which make up the claims in general is represented as run-off triangle. The chain ladder method has known as the most representative one in the estimation of loss reserves based on such run-off triangular data. However, this fails to capture change point in trend. In order to test of structural changes of development factors, we will present the test statistics and procedures. A real data analysis will also be provided.

• The KIPS Transactions:PartB
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• v.14B no.6
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• pp.413-422
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• 2007

This paper addresses a new technique for constructing surface model from a set of wire-frame contours. The most difficult problem of this technique, called contour triangulation, arises when there are many branches on the surface, and causes lots of ambiguities in surface definition process. In this paper, the branching problem is reduced as the surface reconstruction from a set of virtual belts and virtual canyons. To tile the virtual belts, a divide-and-conquer strategy based tiling technique, called the BPA algorithm, is adopted. The virtual canyons are covered naturally by an iterative convex removal algorithm with addition of a center vertex for each branching surface. Compared with most of the previous works reducing the multiple branching problem into a set of tiling problems between contours, our method can handle the problem more easily by transforming it into more simple topology, the virtual belt and the virtual canyon. Furthermore, the proposed method does not involve any set of complicated criteria, and provides a simple and robust algorithm for surface triangulation. The result shows that our method works well even though there are many complicated branches in the object.

• Journal of the Korea Computer Graphics Society
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• v.13 no.4
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• pp.21-27
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• 2007

The 3D Delaunay triangulation is the most widely used method for the mesh creation via the triangulation of a 3D point cloud. However, the method involves a heavy computational cost and, hence, in many interactive applications, it is not appropriate for surface triangulation. In this paper, we propose an efficient triangulation method to create a surface mesh from a 3D point cloud. We divide a set of object points into multiple subsets and apply the 2D Delaunay triangulation to each subset. A given 3D point cloud is cut into slices with respect to the OBB(Oriented Bounding Box) of the point set. The 2D Delaunay triangulation is applied to each subset producing a partial triangulation. The sum of the partial triangulations constitutes the global mesh. As a postprocessing process, we eliminate false edges introduced in the split steps of the triangulation and improve the results. The proposed method can be effectively applied to various image-based modeling applications.

• Communications of Mathematical Education
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• v.31 no.3
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• pp.257-277
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• 2017

The purpose of this research is divide into two kinds. First, develop the mathematical modeling program for mathematically gifted students focused on Voronoi diagram and Delaunay triangulation, and then gifted teachers can use it in the class. Voronoi diagram and Delaunay triangulation are Spatial partition theory use in engineering and geography field and improve gifted student's mathematical connections, problem solving competency and reasoning ability. Second, after applying the developed program to the class, I analyze gifted student's core competency. Applying the mathematical modeling program, the following findings were given. First, Voronoi diagram and Delaunay triangulation are received attention recently and suitable subject for mathematics gifted education. Second,, in third enrichment course(Student's Centered Mathematical Modeling Activity), gifted students conduct the problem presentation, division of roles, select and collect the information, draw conclusions by discussion. In process of achievement, high level mathematical competency and intellectual capacity are needed so synthetic thinking ability, problem solving, creativity and self-directed learning ability are appeared to gifted students. Third, in third enrichment course(Student's Centered Mathematical Modeling Activity), problem solving, mathematical connections, information processing competency are appeared.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.2
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• pp.87-93
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• 2014

Cadastral parcel objects as polygons are fundamental dataset which represent land administration and management of the real world. Thus it is necessary to assure topological seamlessness of cadastral datasets which means no overlaps or gaps between adjacent parcels. However, the problem of overlaps or gaps are frequently found due to non-coinciding edges between adjacent parcels. These erroneous edges are called uncertain edges, and polygons containing at least one uncertain edge are called uncertain polygons. In this paper, we proposed a new algorithm to efficiently search parcels of uncertain polygons between two adjacent cadastral datasets. The algorithm first selects points and polylines around adjacent datasets. Then the Constrained Delaunay Triangulation (CDT) is applied to extract triangles. These triangles are tagged by the number of the original cadastral datasets which intersected with the triangles. If the tagging value is zero, the area of triangles mean gaps, meanwhile, the value is two, the area means overlaps. Merging these triangles with the same tagging values according to adjacency analysis, uncertain edges and uncertain polygons could be found. We have performed experimental application of this automated derivation of partitioned boundary from a real land-cadastral dataset.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.123-134
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• 2000

This paper addresses a new triangulation method for constructing surface model from a set of wire-frame contours. The most important problem of contour triangulation is the branching problem, and we provide a new solution for the double branching problem, which occurs frequently in real data. The multiple branching problem is treated as a set of double branchings and an algorithm based on contour merging is developed. Our double branching algorithm is based on partitioning of root contour by Toussiant's polygon triangulation algorithml[14]. Our double branching algorithm produces quite natural surface model even if the branch contours are very complicate in shape. We treat the multiple branching problem as a problem of coarse section sampling in z-direction, and provide a new multiple branching algorithm which iteratively merge a pair of branch contours using imaginary interpolating contours. Our method is a natural and systematic solution for the general branching problem of contour triangulation. The result shows that our method works well even though there are many complicated branches in the object.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.191-201
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• 1998

지리 정보 시스템에서 수치지도 보정(rubber sheeting)이란 물리적으로 동일 지역을 나타내고 있지만 일치하지 않는 두 지도사이의 불일치한 부분이 일치되도록 보정해 주는 것을 말한다. 불일치 종류는 수치지도를 생성하는 방법과 과정 등에서 발생할 수 있으며 또한 시간의 흐름에 따라 변화는 지리 정보의 특성으로 인해 발생하기도 한다. 본 논문에서는 지리 정보 시스템의 성능을 저하시키는 중요한 원인인 불일치 문제를 해결하기 위한 새로운 수치지도 보정 알고리즘을 제시한다. 제시한 방법은 다각형 커널의 무게 중심을 이용하여 다각형을 삼각분할한 후 삼각형 매핑을 적용하는 것이다. 다각형 외부에 위치한 시설물에 대해서도 동일한 방법을 적용하기 위해 제한된 딜로니(Delaunay)삼각분할을 이용하여 외부 영역을 다각형의 집합으로 만들어 주는 방법을 제시한다. 또한 본 논문에서는 수치지도 보정 결과를 평가하기 위한 측정 함수를 제시하였다. 측정 함수는 지리 정보의 특성을 구분짓는 세 가지 중요한 요소인 방향적(directional), 위상적(topological), 측량적(metrical)특성을 이용한다. 그리고 수치지도와 다양한 테스트 데이터를 이용하여 제시한 기법의 성능을 실험하고 그 결과를 측정 함수로 분석하여 제시한 기법이 불일치 해결에 좋은 결과를 보여 줌을 밝힌다.

• Clinics in Shoulder and Elbow
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• v.16 no.1
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• pp.17-26
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• 2013

Purpose: A comparison of the radiographic and the clinical outcomes between two different surgical approaches-Deltoid splitting and Delto-pectoral interval-on the proximal humerus fractures treated by locking compressive plate (LCP), is done. Materials and Methods: Medical records and pre- and postoperative radiographs were reviewed retrospectively for 75 adult patients who underwent surgical fixations with locking compressive plates from May 2005 to December 2011. Patients were divided into two groups according to the surgical methods. Differences in the neck-shaft angle between immediate postoperative period and final follow-up were compared between the two groups. Differences in constant score and Korean shoulder score (KSS) between affected arms and contralateral arms at final follow-up were also compared. Results: The differences in the neck-shaft angle between immediate postoperative period and at final follow-up was 12.04 degrees on average in Deltoid splitting approach and 10.20 degrees in Delto-pectoral interval approach, which was not statistically significant. Differences in constant score/KSS between the affected arm and the contralateral arm were 13.78/22.74 points in deltoid-splitting approach on average and 19.41/31.13 points in Delto-pectoral interval approach, showing that deltoid-splitting approach is significantly superior. Conclusion: Deltoid-splitting approach showed better functional outcomes in the fracture reduction and internal fixation using LCP for the treatment of unstable proximal humerus fractures.