• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.721-723
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• 2002

본 논문은 한 장의 사진으로부터 선분과 선분의 중점을 이용한 원시기하모델의 3차원 재구성 시스템을 제안한다. 이 시스템은 선분과 중점을 추출할 수 있는 미리 정의된 다면체를 원시기하모델로 사용하며 그 원시기하모델의 각 점을 사용자가 사진에 매핑 시키는 것으로서 3차원 재구성이 수행된다. 미리 정의된 원시기하모델의 사용은 사용자에게 기존의 소실점 입력 방식보다 직관적인 3차원 재구성을 가능하게 한다. 사진에 매핑된 원시기하모델이 포함하고 있는 2차원상의 선분과 선분의 중점으로부터 원시기하모델을 3차인 재구성한다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.4
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• pp.168-176
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• 2005

We propose a method for 3-dimensionally reconstructing an object using a line that includes the midpoint information from a single image. A pre-defined polygon is used as the primitive and the recovery is processed from a single image. The 3D reconstruction is processed by mapping the correspondence point of the primitive model onto the photo. In the recent work, the reconstructions of camera parameters or error minimizing methods through iterations were used for model-based 3D reconstruction. However, we proposed a method for the 3D reconstruction of primitive that consists of the segments and the center points of the segments for the reconstruction process. This method enables the reconstruction of the primitive model to be processed using only the focal length of various camera parameters during the segment reconstruction process.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.705-713
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• 2021

The modulation transfer function (MTF) is calculated to analyze the resolution of the spatial frequency of the image acquired from the x-ray imaging system. In general, the response function of the detector acquires a line spread function (LSF) using a slit-camera, and derives a modulation transfer function through a Fourier transform. Because of the fact that the x-ray must always be incident on the center of the slit-camera, the tilt of the detector and slit-camera caused by the experimenter will affect the detector performance. In addition, if the tilt increases, the performance evaluation of the x-ray image system will be problematic. In this study, we analyzed the experimental and analytical models in the modulation transfer function, ie, the Fourier domain, based on the experimental error and analyzed the effect on the spatial frequency. Furthermore, performance evaluation is being carried out for various x-ray imaging systems, and experimental errors are indispensable, and the extent to which they can be tolerated should be reviewed.

• The Journal of Korean Association of Computer Education
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• v.6 no.4
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• pp.61-69
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• 2003

RG(Railway Graph), which is a connected graph structure with the concepts of internal and external edges, is a data structure for representing railway assignments in a track network. In RG, it is possible to represent railway connectivities considering it's forward direction which is impossible in a digraph representation. But with RC, we can not still represent an othogonoal railway crossing in a track network. In this paper, we extend RG using the concept of dummy edge. Using ERG(Extended Railway Graph), we describe a method to consistently represent track network including othogonoal railway crossings, data structure for our ERG, and path allocation algorithm in ERG.

• The KIPS Transactions:PartB
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• v.12B no.5 s.101
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• pp.567-576
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• 2005

This paper proposes an image-based modeling method which recovers 3D models using projected line segments in multiple images. Using the method, a user obtains accurate 3D model data via several steps of simple manual works. The embedded nonlinear minimization technique in the model parameter estimation stage is based on the distances between the user provided image line segments and the projected line segments of primitives. We define an error using a finite line segment and thus increase accuracy in the model parameter estimation. The error is defined as the sum of differences between the observed image line segments provided by the user and the predicted image line segments which are computed using the current model parameters and camera parameters. The method is robust in a sense that it recovers 3D structures even from partially occluded objects and it does not be seriously affected by small measurement errors in the reconstruction process. This paper also describesexperimental results from real images and difficulties and tricks that are found while implementing the image-based modeler.

• The KIPS Transactions:PartA
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• v.18A no.5
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• pp.215-224
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• 2011

In this paper, a mechanism connecting all weighted migration routes with minimum cost with EGOSST is proposed. Weighted migration routes may be converted to weighted input edges considered as not only traces but also traffics or trip frequencies of moving object on communication lines, roads or railroads. Proposed mechanism can be used in more wide and practical area than mechanisms considering only moving object traces. In our experiments, edge number, maximum weight for input edges, and detail level for grid are used as input parameters. The mechanism made connection cost decrease average 1.07% and 0.43% comparing with the method using weight minimum spanning tree and weight steiner minimum tree respectively. When grid detail level is 0.1 and 0.001, while each execution time for a connecting solution increases average 97.02% and 2843.87% comparing with the method using weight minimum spanning tree, connecting cost decreases 0.86% and 1.13% respectively. This shows that by adjusting grid detail level, proposed mechanism might be well applied to the applications where designer must grant priority to reducing connecting cost or shortening execution time as well as that it can provide good solutions of connecting migration routes with weights.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.610-612
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• 2003

일상 생활에서 자동차의 수가 증가함에 따라 최근 자동차 번호판을 자동으로 인식하는 시스템이 다양한 곳에서 이용되고 있다. 일례로 공항이나 아파트 단지에서 자동으로 문을 개폐해주는 시스템을 도입하고 있다. 기존에 주차권을 통한 개폐기와의 차이점 달려오던 자동차가 일정 속도만 유지하면 자동으로 번호를 인식하는 점이다. 또한 번호판을 통해 정확한 자동차에 대한 정확한 정보를 관리할 수 있다. 이러한 시스템을 위해서 자동차 번호판 영역의 정확한 추출이 필요하다. 본 논문은 자동차 번호판 영역을 RGB영역으로 인식하던 시스템에 수직, 수평 선분을 포함하여 기존에 RGB영역으로 인식하던 시스템의 단점을 보완하고 더 나은 인식시스템 구현하고 실험 하였다.

• Journal of the Korean School Mathematics Society
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• v.10 no.3
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• pp.341-351
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• 2007

The primary purpose of this treatise is to suggest the solutions as follows for the errors concerning the triangle determination and congruence in every Korean mathematics textbook for 7th graders: showing that SsA, along with SSS, SAS, ASA, should also be included as the condition for triangle determination, congruence and similarity; proving that contrary to what has been believed, minimality applies only to congruence and similarity but not to determination; examining related Euclidean propositions; discussing the confusion about the characteristics of determination and congruence; and considering the negative effects of giving definite figures in construction education. The secondary purpose is to analyze the significance of triangle determinant that is not dealt with in either Euclid's Elements or the text books in the U.S. or Japan, and suggest a way to effectively deal with triangle determination and congruence in education.

• Journal of the Korean School Mathematics Society
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• v.24 no.2
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• pp.173-190
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• 2021

This study analyzed the proof of the inverse square law, which is said to be the core of Newton's , in relation to the geometric limit. Newton, conscious of the debate over infinitely small, solved the dynamics problem with the traditional Euclid geometry. Newton reduced mechanics to a problem of geometry by expressing force, time, and the degree of inertia orbital deviation as a geometric line segment. Newton was able to take Euclid's geometry to a new level encompassing dynamics, especially by introducing geometric limits such as parabolic approximation, polygon approximation, and the limit of the ratio of the line segments. Based on this analysis, we proposed to use Newton's geometric limit as a tool to show the usefulness of mathematics, and to use it as a means to break the conventional notion that the area of the curve can only be obtained using the definite integral. In addition, to help the desirable use of geometric limits in school mathematics, we suggested the following efforts are required. It is necessary to emphasize the expansion of equivalence in the micro-world, use some questions that lead to use as heuristics, and help to recognize that the approach of ratio is useful for grasping the equivalence of line segments in the micro-world.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.879-888
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• 2006

Recently many researchers have focused on management of Historical trajectories of moving objects in Euclidean spaces due to numerous sizes of accumulated data over time. However, the movement of moving objects in real applications generally has some constraints, for example vehicles on roads can only travel along connected road networks. In this paper, we propose an indexing method for trajectories of moving objects on road networks in order to process the network-based spatiotemporal range query. Our method contains the connect information of road networks to use the network distance for query processing, deals with trajectories which are represented by road segments in road networks, and manages them using multiple R-trees assigned per each road segment. Furthermore, it has a structure to be able to share R-tree among several road segments in large road networks. Consequently, we show that our method takes about 30% less in node accesses for the network-based spatiotemporal range query processing than other methods based on the Euclidean distance by experiments.