• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.82-88
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• 2002

A simple beam subjected to a uniformly distributed tangential follower force and the successive two moving spring-mass systems upon it constitute this vibration system. The influences of the velocities of the moving spring-mass system, the distance between the successive two moving spring-mass systems and the uniformly distributed tangential follower force have been studied on the dynamic behavior of a simple beam by numerical method. The uniformly distributed tangential follower force is considered within its critical value of a simple beam without the successive two moving spring-mass systems, and three kinds of constant velocities and constant distance of the successive two moving spring-mass systems are also chosen. Their coupling effects on the transverse vibration of the simple beam are inspected too.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.2
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• pp.145-153
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• 2006

An optimal capturing trajectory for a moving object is proposed in this paper based on the observation that a single-curvature path is more accurate than double-or triple-curvature paths. Moving distance, moving time, and trajectory error are major factors considered in deciding an optimal path for capturing the moving object. That is, the moving time and distance are minimized while the trajectory error is maintained as small as possible. The three major factors are compared for the single and the double curvature trajectories to show superiority of the single curvature trajectory. Based upon the single curvature trajectory, a kinematics model of a mobile robot is proposed to follow and capture the moving object, in this paper. A capturing scenario can be summarized as follows: 1. Motion of the moving object has been captured by a CCD camera., 2. Position of the moving object has been estimated using the image frames, and 3. The mobile robot tries to follow the moving object along the single curvature trajectory which matches positions and orientations of the moving object and the mobile robot at the final moment. Effectiveness of the single curvature trajectory modeling and capturing algorithm has been proved, through simulations and real experiments using a 2-DOF wheel-based mobile robot.

• Spatial Information Research
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• v.20 no.5
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• pp.77-89
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• 2012

Walking is the most basic personal mobility and its importance and concern is ever increasing with the highlighting of a new paradigm, such as transit oriented development, sustainable development and revitalization of green transport. The existing analytical research on pedestrian network is using a pedestrian's moving distance to a destination and integration in space syntax theory as its representative accessibility factors. However, the uniplanar network moving distance fails to reflect topographic characteristics, so the moving distance could show a similar result value in case of the regions for analysis that have a similar network structure to each other. Accordingly, the aim of this study is to suggest a new analytical methodology on pedestrian network accessibility in consideration of the grade in pedestrian sections and a pedestrian's size. this study, in its analysis of a uniplanar pedestrian network moving distance, analyzed the pedestrian network moving distance in consideration of the grade in pedestrian sections, and even the pedestrian network moving distance in consideration of a pedestrian's size, and suggested the methodology on pedestrian network accessibility analysis in consideration of a more substantive pedestrian's characteristics. It is hoped that the methodology used by this study will be used as the methodology on pedestrian network analysis which can reflect topographic characteristics in the pedestrian network analysis, and take a more substantive pedestrian's movement into account.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.45-53
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• 2006

This paper proposes a method for an effective intelligent route decision for automatic moving robots(AMR) using a 2D spatial map of a stereo camera system. In this method, information about depth and disparity map are detected in the inputting images of a parallel stereo camera. The distance between the automatic moving robot and the obstacle is detected, and a 2D spatial map is obtained from the location coordinates. Then the relative distances between the obstacle and other objects are deduced. The robot move automatically by effective and intelligent route decision using the obtained 2D spatial map. From experiments on robot driving with 240 frames of stereo images, it was found that the error ratio of the calculated distance to the measured distance between objects was very low, 1.52[%] on average.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1508-1512
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• 2005

A real time tracking and matching of the screen cursor corresponding to the iris moving by measuring distance between vertical movement and horizontal movement of iris is presented in this paper. The screen cursor is tracked and matched with the distance md direction moving the center-positioned coordinate of iris. The experimental result shows that the moving of iris and screen cursor are accord with distance and size of screen and the optimal tolerance is reduced the tracking error.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.637-642
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• 2011

In this paper, a new technique to estimate the distances between a vanishing point and moving objects is proposed. A vanishing point for an input image is estimated and it use to extract distance form the vanishing point to a moving object. Using the obtained distances, moving objects is extracted. In simulation results, several performances for a test image sequnce is shown.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.935-942
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• 2021

Involuntary movement of internal organs by respiration is a factor that greatly affects the results of radiotherapy and diagnosis. In this study, a moving phantom was fabricated to simulate the movement of an organ or a tumor according to respiration, and ¹⁸F-FDG PET/CT scan images were acquired under various respiratory simulating conditions to analyze the movement range of the tumor movement by respiration, the level of artifacts according to the size of the tumor and the maximum standardized uptake value (SUVmax). Based on Windows CE 6.0 as the operating system, using electric actuator, electric actuator positioning driver, and programmable logic controller (PLC), the position and speed control module was operated normally at a moving distance of 0-5 cm and 10, 15, and 20 reciprocations. For sphere diameters of 10, 13, 17, 22, 28, and 37 mm at a delay time of 100 minutes, 80.4%, 99.5%, 107.9%, 113.1%, 128.0%, and 124.8%, respectively were measured. When the moving distance was the same, the difference according to the respiratory rate was insignificant. When the number of breaths is 20 and the moving distance is 1 cm, 2 cm, 3 cm, and 5 cm, as the moving distance increased at the sphere diameters of 10, 13, 17, 22, 28, and 37 mm, the ability to distinguish images from smaller spheres deteriorated. When the moving distance is 5 cm compared to the still image, the maximum values of the standard intake coefficient were 18.0%, 23.7%, 29.3%, 38.4%, 49.0%, and 67.4% for sphere diameters of 10, 13, 17, 22, 28, and 37 mm, respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.599-604
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• 2013

Path planning of mobile robots has a purpose to design an optimal path from an initial position to a target point. Minimum driving time, minimum driving distance and minimum driving error might be considered in choosing the optimal path and are correlated to each other. In this paper, an efficient driving trajectory is planned in a real situation where a mobile robot follows a moving object. Position and distance of the moving object are obtained using a web camera, and the rotation angular and linear velocities are estimated using Kalman filters to predict the trajectory of the moving object. Finally, the mobile robot follows the moving object using a single curvature trajectory by estimating the trajectory of the moving object. Using the estimation by Kalman filters and the single curvature in the trajectory planning, the total tracking distance and time saved amounts to about 7%. The effectiveness of the proposed algorithm has been verified through real tracking experiments.

• Journal of Korea Game Society
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• v.17 no.4
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• pp.55-62
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• 2017

In this study, motion simulation of Walk-through was evaluated with HMD(Head Mounted Display). More Specifically, we examined the changes of the degree of object density placed around virtual space on psychological moving distance, moving speed, and moving time. The results were as follows. First, the difference between the experimental conditions(low density, Medium density, High density) was significant. Second, as the density of the surrounding objects increased, the average point of moving time, moving speed, and moving distance rose compared to the basic conditions. Third, it was found that the surrounding objects improved the sense of time, speed and distance in motion simulation in virtual space.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.88-93
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• 1998

This paper presents a new solution approach to moving obstacle avoidance problem for a mobile robot. A new concept avoidability measure(AVM) is defined to describe the state of a pair of a robot and an obstacle regarding the collision between them. As an AVM, virtual distance function(VDF) is derived as a function of the distance from the obstacle to the robot and outward speed of the obstacle relative to the robot. By keeping the virtual distance above some positive limit value, the robot avoids the obstacle. In terns of the VDF, an artificial potential field is constructed to repel the robot away from the obstacle and to attract the robot toward a goal location. At every sampling time, the artificial potential field is updated and the force driving the robot is derived form the gradient of the artificial potential field. The suggested algorithm drives the robot to avoid moving obstacles in real time. Since the algorithm considers the mobility of the obstacle as well as the distance, it is effective for moving obstacle avoidance. Some simulation studies show the effectiveness of the proposed approach.