• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.1-10
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• 2013

This paper proposes a method to detect vanishing points of an indoor scene using line segment classification. Two-stage vanishing points detection is carried out to detect vanishing point in indoor scene efficiently. In the first stage, the method examines whether the image composition is a one-point perspective projection or a two-point one. If it is a two-point perspective projection, a horizontal line through the detected vanishing point is found for line segment classification. In the second stage, the method detects two vanishing points exactly using line segment classification. The method is evaluated by synthetic images and an image DB. In the synthetic image which some noise is added in, vanishing point detection error is under 16 pixels until the percent of the noise to the image becomes 60%. Vanishing points detection ratio by A.Quattoni and A.Torralba's image DB is over 87%.

• Journal of IKEEE
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• v.13 no.2
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• pp.181-185
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• 2009

In this paper, we are concerned with a 3D line segment extraction method by area-based stereo matching technique. The main idea is based on line fitting of elevation data on 2D line coordinates of ortho-image. Elevation data and ortho-image can be obtained by well-known area-based stereo matching technique. In order to use elevation in line fitting, the elevation itself should be reliable. To measure the reliability of elevation, in this paper, we employ the concept of self-consistency. We test the effectiveness of the proposed method with a quantitative accuracy analysis using synthetic images generated from Avenches data set of Ascona aerial images. Experimental results indicate that our method generates 3D line segments almost 7.5 times more accurate than raw elevations obtained by area-based method.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1430-1441
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• 2012

In this paper, we present an algorithm that quickly and effectively estimates orthogonal vanishing points in equirectangular images of urban environment. Our algorithm is based on the RANSAC (RANdom SAmple Consensus) algorithm and on the characteristics of the line segment in the spherical panorama image of the $360^{\circ}$ longitude and $180^{\circ}$ latitude field of view. These characteristics can be used to reduce the geometric ambiguity in the line segment classification as well as to improve the robustness of vanishing point estimation. The proposed algorithm is validated experimentally on a wide set of images. The results show that our algorithm provides excellent levels of accuracy for the vanishing point estimation as well as line segment classification.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.176-180
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• 2003

The paper presents an efficient method of extracting line segment in a local map of a robot's surroundings. The local map is composed of 2-D grids that have both the occupancy and orientation probabilities using sonar sensors. To find the shape of an object in a local map from orientation information, the orientations are clustered into several groups according to their values. The line segment is , then, extracted from the clusters based on Hough transform. The proposed technique is illustrated by experiments in an indoor environment.

• The Mathematical Education
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• v.50 no.1
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• pp.27-40
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• 2011

The purpose of this paper is to analyze and discuss the viewpoint dealing with the fundamental figures-point, line segment, and angle-of elementary school teachers. In fact, our main subjects in this article are as follows; how do elementary school teachers deal with the fundamental figures?, what is the general notion about the fundamental figures of elementary school teachers? Our such subjects come from the survey results about the 'fundamental figures in J. A. Ko(2009); the elementary school students have a tendency to regard the fundamental figures as not mathematical figures. In this article, we discuss mainly the meta-cognitive shift in the transform of notion, for example, from 'congruent' concept to 'equal' concept, about the fundamental figures.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.601-607
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• 2005

In this paper, we aggregate multi-links information between boundary nodes using the line segment scheme that aggregates topology information within PG referring bandwidth and delay parameter. To do this, we propose a modified line segment algorithm using two line segment method that represents two points which consist of delay-bandwidth pair to reduce topology information and provide a flexibility to the multiple-links aggregation. And we apply it to current star topology aggregation. Through the simulation result analysis, the proposed star topology aggregation scheme presents the better performance than existing scheme.

• The KIPS Transactions:PartB
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• v.9B no.3
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• pp.375-382
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• 2002

Handwritten character recognition is classified into on-line handwritten character recognition and off-line handwritten character recognition. On-line handwritten character recognition has made a remarkable outcome compared to off-line hacdwritten character recognition. This method can acquire the dynamic written information such as the writing order and the position of a stroke by means of pen-based electronic input device such as a tablet board. On the contrary, Any dynamic information can not be acquired in off-line handwritten character recognition since there are extreme overlapping between consonants and vowels, and heavily noisy images between strokes, which change the recognition performance with the result of the preprocessing. This paper proposes a method that effectively extracts the stroke including dynamic information of characters for off-line Korean handwritten character recognition. First of all, this method makes improvement and binarization of input handwritten character image as preprocessing procedure using watershed algorithm. The next procedure is extraction of skeleton by using the transformed Lu and Wang's thinning: algorithm, and segment pixel array is extracted by abstracting the feature point of the characters. Then, the vectorization is executed with a maximum permission error method. In the case that a few strokes are bound in a segment, a segment pixel array is divided with two or more segment vectors. In order to reconstruct the extracted segment vector with a complete stroke, the directional component of the vector is mortified by using right-hand writing coordinate system. With combination of segment vectors which are adjacent and can be combined, the reconstruction of complete stroke is made out which is suitable for character recognition. As experimentation, it is verified that the proposed method is suitable for handwritten Korean character recognition.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.132-151
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• 2022

Vehicle localization is one of the core technologies for autonomous driving. Image-based localization provides location information efficiently, and various related studies have been conducted. However, the image-based localization methods using feature points or lane information has a limitation that positioning accuracy may be greatly affected by road and driving environments. In this study, we propose a line segment matching framework for accurate vehicle localization. The proposed framework consists of four steps: line segment extraction, merging, overlap area detection, and MSLD-based segment matching. The proposed framework stably performed line segment matching at a sufficient level for vehicle positioning regardless of vehicle speed, driving method, and surrounding environment.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.305-315
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• 2019

Extremely long-span transmission tower-line system is an indispensable portion of an electricity transmission system, and its failures or collapse can impact on the entire electricity grid, affect the modern life, and cause great economic losses. It is therefore imperative to investigate the failure and safety of the transmission tower subjected to ground motions. In the present study, a detailed finite element (FE) model of a representative extremely long-span transmission tower-line system is established. A segmental damage indicator (SDI) is proposed to quantitatively assess the damage level of each segment of the transmission tower under earthquakes. Additionally, parametric studies are conducted to investigate the influence of different ground motions and incident angles on the ultimate capacity and weakest segment of the transmission tower. Finally, the collapse fragility curve in terms of the maximum SDI value and PGA is plotted for the exampled transmission tower. The results show that the proposed SDI can quantitatively assess the damage level of the segments, and thus determine the ultimate capacity and weakest segment of the transmission tower. Moreover, the different ground motions and incident angles have a significant influence on the SDI values of the transmission tower, and the collapse fragility curve is utilized to evaluate the collapse resistant capacity of the transmission tower subjected to ground motions.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.6
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• pp.461-469
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• 2017

A segment of the wave board has been expressed as a submerged line segment in the two dimensional wave flume. The lower end of the line segment could be extended to the bottom of the wave flume and the other opposite upper end of the board could be extended to the free surface. It is assumed that the motion of the wave board could be defined by the sinusoidal motion in horizontal direction on either end of the wave board. When the amplitude of sinusoidal motion of the wave board on lower and upper end are equal, the wave board motion could express the horizontally oscillating submerged segment of piston type wave generator. The submerged segment of flap type wave generator also could be expressed by taking the motion amplitude differently for the either end of the board. The pivot point of the segment motion could play a role of hinge point of the flap type wave generator. Simplified analytic solution of oscillating submerged wave board segment in water of finite depth has been derived through the first order perturbation method at two dimensional domain. The case study of the analytic solution has been carried out and it is found out that the solution could be utilized for the design of wave generator with arbitrary shape by linear superposition.