• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.687-696
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• 2014

This paper presents a semantic object extraction method using user's stroke input, color, and depth information. It is supposed that a semantically meaningful object is surrounded with a few strokes from a user, and has similar depths all over the object. In the proposed method, deciding the region of interest (ROI) is based on the stroke input, and the semantically meaningful object is extracted by using color and depth information. Specifically, the proposed method consists of two steps. The first step is over-segmentation inside the ROI using color and depth information. The second step is semantically meaningful object extraction where over-segmented regions are classified into the object region and the background region according to the depth of each region. In the over-segmentation step, we propose a new marker extraction method where there are two propositions, i.e. an adaptive thresholding scheme to maximize the number of the segmented regions and an adaptive weighting scheme for color and depth components in computation of the morphological gradients that is required in the marker extraction. In the semantically meaningful object extraction, we classify over-segmented regions into the object region and the background region in order of the boundary regions to the inner regions, the average depth of each region being compared to the average depth of all regions classified into the object region. In experimental results, we demonstrate that the proposed method yields reasonable object extraction results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.797-800
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• 2008

Online signature verification system is widely used in banking account, credit card and so on, because system for online signature verification is easy to implementation and inexpensive. Therefore there are a lot of study on online signature verification. However there is little research about online signature is safe or not. This paper shows a way of online signature estimation using various information of signature. This paper make a experiment about relation sorority grade of online signature and 2-D information of online signature like the number of strokes and cross points, density of points, standard deviation of direction, velocity and acceleration, lengths of signature and convex hull etc. Finally, this paper presents several features of safe online signature.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.143-153
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• 2005

J.Y. CHOI,S. J. KIM, E. L. LEE. Change of plantar pressure Distribution of Open Stance during Forehand Strke in Tennis. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, PP. 143-153, 2005. Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and close stance and it is very important to know the patterns of plantar pressure distribution for the better understanding of forehand stroke. Therefore, the purpose of this study was to investigate the change of plantar pressure distribution in open stance during forehand stroke in tennis. Three high school tennis players were recruited for the study and required to perform forehand stroke five consecutive trials in the condition of open stance. The forehand strokes were filmed with two digital video cameras and measured with pedar system for plantar pressure. The plantar regions under the foot were divided into 3 regions, which were forefoot, midfoot, and rear foot. In conclusion, The plantar pressure of open stance during forehand stroke was distributed more largely to the right foot. The plantar pressure of open stance during forehand stroke was distributed more weight loads on forefoot of right than heel of right

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.122-123
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• 2007

고전압 가스 차단기에서는 긴 스트로크 동안 가스반발력을 극복하고 빠르게 차단할 수 있는 액추에이터가 필요하다 기존에는 공압식, 유압식, 스프링 액추에이터와 같은 기계적인 장치가 사용되었다. 그러나 기존 액추에이터에서는 소음, 에너지 손실, 고가적의 단점이 있어, 근래에 들어 PMA, 모터와 같은 전기적 장치도 사용되고 있다. 전기 액추에이터는 간단한 구조로 되어 있어 기계적 손실을 줄일 수 있고 소음이 적은 장점이 있다. 전자석 조작기의 연구 필요성에 따라 새로운 형태의 전자석 조작기 Electro Magnetic Force driving Actuator(EMFA)가 개발되어 고전압 가스 차단기에 적합하다고 분석되었다. EMFA의 동특성을 얻기 위한 과도상태 해석에서는 2차원 유한요소법을 이용하여 얻은 전자기적 해석을 회로, 운동방정식과 연계하여 시간차분법을 사용하여 해석하였다. 하지만 2차원과 3차원의 전자기 해석은 차이를 보인다는 것을 확인하였고 정확한 전자기 해석을 위해 3차원 동특성 해석을 수행하여 실험결과와 비교하였다.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.147-152
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• 2006

The purpose of this study was to develop the experimental machine for the putting strokes. This experimental machine is called Pendulum Putting Machine(PPM). The height of PPM is 75cm and the mass is 10kg. To make the frame of this machine, 24 and 20 diameters of iron pipes were used. Bottom of the frame(bottom girdle) was made with circle shape and top of the frame(top girdle) was made with rectangular shape. Above the top girdle, iron plate($12{\times}17{\times}0.5cm$) was placed to connect the ball bearing. At the top of the frame two ball bearings with axis were placed for the diverse lies of putters and irons. To verify usefulness of this machine, experiments were executed with the PPM. Two major experimental conditions were hitting points(sweet spot, toe side, heel side) and hitting places(bottom, 3cm before bottom, 3cm after bottom). Eleven different cases were tested. The results showed that the diversity of the ball placement(distance and direction) was acceptable(distance range, 2.70-5.87 standard deviation; direction range, 1.71-4.65 standard deviation). Overall the Pendulum Putting Machine is very useful for the study of putting and driving strokes.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.85-94
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• 2006

The purpose of this study was to analyze the kinematics variables of during forehand stroke by stance patterns. Eight high school tennis players were chosen for the study, who have never been injured for last six months, in Busan. They performed horizontal swing and vertical swing that it was done each five consecutive trial in the condition of square, open and semi-open stance. It was filmed by 6 video camera and used with 3-dimensional motion analyzer system. The following kinematic variables were analyzed in relation to angle of segment( shoulder, hip and knee joint). The conclusion were as follow: 1. The angle of hip joint represented at impact that horizontal swing was not significant difference by stance patterns but vertical swing was increased in open stance than square and semi-open stance. 2. The angle of both knee was not significant difference between all stance types and swing patterns. 3. The angle of shoulder, hip and knee joint rotation showed that open stance was increased than square and semi-open stance in all swing types and event.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.119-126
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• 1996

A hydraulic type active control system has been developed for the purpose of vibration suppression of ship superstructrures. The active mass of the developed system weighs about three tons and is designed to have ${\pm}5mm$ stroke below 10Hz. Thus maximum control force of the system is about 60kN. Performance test of the developed system has been carried out on a 4,400TEU contrainer carrier built in Samsung Heavy Industry Co., LTD. Through the exciter tests, it has been confirmed that the vibration levels of the superstructure can be reduced to about 20% of the uncontrolled levels near resonant frequency.

• Journal of the Korea Computer Graphics Society
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• v.16 no.2
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• pp.19-28
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• 2010

In this paper, we proposes a method that analyzes the characteristics and patterns of color juxtaposition based on the color wheel used by pointillism painter and an algorithm that generates pointillistic images by applying obtained analysis data. In order to analyze color juxtaposition of pointillism, we extract the stroke colors of real painting and find the most similar probability density functions(PDFs) through applying good-of-fit tests for the probabilistic distribution of stroke colors. By performing the juxtaposition of color based on the found PDFs, we can convert input image to pointillistic image effectively. It can be seen that this study shows reliability in the use of data obtained from actual paintings and that leads to perform a reasonable work.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.39-46
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• 2011

The purpose of this study was to examine differences between players who bend the left elbow and those who stretch it during the forward swing from BST to BC in a 2-handed backhand stroke among outstanding high school tennis players, and to assess the detailed 3D rotational kinematic characteristics of the shoulder and the hip. Statistically significant differences were observed between groups in the longitudinal axis rotation angle of the shoulder and the angle between the shoulder and the arm at BST, and in the side to side movement of the shoulder, the up and down movement of the hip, the side tilt angular velocity of the shoulder, the side tilt angular velocity of the hip, and the front tilt angular velocity of the hip at BC. The difference in the longitudinal axis rotation angle of the shoulder between the 2 groups suggests a difference in the flexibility of the joint in the shoulder arm racquet system. The longitudinal axis rotation angular velocity of the shoulder reached its peak at 75 % of the duration of the analyzed segment and then decreased little by little until BC. This time is considered the stage for increasing the angular velocity of the upper arm, the forearm, the hand and then the racquet, which are more distal segments than the shoulder.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.158-168
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• 2012

This paper deals with TVC nozzle stroke verification test and corresponding analysis techniques related to kick motor TVC system of KSLV-I second stage. It is shown that the relationship between TVC stroke and potentiometer voltage is revealed via the open-loop stroke verification test, and other major operational parameters including nozzle alignment error, actuation error, neutral position, radius of nozzle rotation, location of nozzle rotation center, angle conversion coefficients, etc. are analyzed via the closed-loop stroke verification test. The TVC stroke verification test results for the first and second flight model of KSLV-I show that all TVC operational parameters of KSLV-I second stage were normally setup for the first and second flight tests.