• Journal of Mechanical Science and Technology
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• v.19 no.7
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• pp.1503-1516
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• 2005

Mean flow and turbulence properties of developing turbulent flows in a 90 degree square bend with span-wise rotation are measured by a hot-wire anemometer. A slanted wire is rotated into 6 orientations and the voltage outputs from them are combined to obtain the mean velocity and the Reynolds stress components. Combined effects of the centrifugal and Coriolis forces due to the curvature and the rotation of the bend on the mean motion and turbulence structures are investigated experimentally. Results show that the two body forces can either enhance or counteract each other depending on the flow direction in the bend.

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.332-338
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• 2003

Content-based image retrieval is the research of images from database, that are visually similar to given image examples. Gabor functions and Gabor filters are regarded as excellent methods for feature extraction and texture segmentation. However, they have a disadvantage not to perform well in case of a rotated image because of its direction-oriented filter. This paper proposes a method of extracting local texture features from blocks with central interest points detected in an image and a rotation invariant Gabor wavelet filter. We also propose a method of comparing pattern histograms of features classified by VQ (Vector Quantization) among images.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.6
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• pp.547-552
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• 1999

Langasite$(La_{3}Ga_{5}SiO_{14})$ single crystal was successfully grown by Floating Zone (FZ) method and characterized. The growth rate was 1.5 mm/h and the rotation speed was 15 rpm for an upper rotation and 13 rpm for a lower rotation. The grown crystal was 12 mm in length and 6 mm in diameter. The grown crystal was dark orange color and it was grown along [001] direction. The composition of grown crystal and the structure were analyzed using XRD and WDS. The electrical properties of grown crystal at various frequencies and temperatures were discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.12
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• pp.1044-1050
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• 2001

This paper presents firstly the method of Euler angle matching designing the transfer alignment using the attitude matching. In this method, the observation directly uses Euler angle difference between MINS and SINS so it needs to describe the rotation vector error to the Euler angle error. The rotation vector error related to the Euler angle error is derive from the direction cosine matrix error equation. The feasibility of the Kalman filter designed for the transfer alignment by Euler angle matching is analyzed by the alignment error results with respect to the roll angle the pitch angle, and the yaw angle matching.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.1
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• pp.6-14
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• 2011

This paper presents a high-speed QR decomposition architecture for the multi-input-multi-output (MIMO) receiver based on Givens rotation. Under fast-varying channel, since the inverse matrix calculation has to be performed frequently in MIMO receiver, a high performance and low latency QR decomposition module is highly required. The proposed QR decomposition architecture is composed of Sign-Select Lookahead (SSL) coordinate rotation digital computer (CORDIC). In the SSL-CORDIC, the sign bits, which are computed ahead to select which direction to rotate, are used to select one of the last iteration results, therefore, the data dependencies on the previous iterations are efficiently removed. Our proposed QR decomposition module is implemented using TSMC 0.25 ${\mu}M$ CMOS process. Experimental results show that the proposed QR architecture achieves 34.83% speed-up over the Compact CORDIC based architecture for the 4 ${\times}$ 4 matrix decomposition.

• Journal of The Korean Astronomical Society
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• v.9 no.1
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• pp.9-14
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• 1976

Godel models of the universe filled with fluid are studied in the framework of the Einstein-Cartan theory of gravitation. It is assumed that the models admit a group of motions simply transitive on space-time. The combined effects of spin and rotation(vorticity) are studied with a particular attention to whether the held equations impose any restriction on alignement of spin direction (a polarized spin distribution). The solutions are found explicitly in a closed form, which show that spin components are vanishingly small except in the direction of z-axis (the compass of inertia) in which they can assume an arbitrary distribution.

• Journal of the Korean Society of Earth Science Education
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• v.5 no.1
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• pp.20-30
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• 2012

The purpose of this study is to find how elementary students who have different spatial ability affects their understandings on the concept of the rotation of the earth. In order to perform this study, four 5th grade students were picked out of 85 students in Seoul. They had the same conceptual achievement on the movement of celestial bodies but had different spatial abilities. The results of this study were as follows : Regardless of their spatial ability, they understand how day and night are performed, and understand the fact that diurnal motions of moon are related to the rotation of the earth. Also, the students who had higher spatial abilities showed better understanding on the concept of the rotation of the earth and understood the reconstructed concepts in stereoscopic space. But the students who had lower spatial abilities did not fully understand the concept of the rotation of the earth and just memorized them as fragmentary concepts. As for the gender differences, the boy students who had higher spatial ability explained the concept clearly and the others who had lower spatial ability had difficulty in understanding the rotation direction of the earth related with the diurnal movement of celestial bodies. In the same manner, the girl students who had higher spatial ability explained the concepts concretely and the others who had lower spatial ability had difficulty in explaining the concepts by operating them stereoscopically. Therefore, developing teaching methods and studying data and so on, for the girl students, they should be trained to operate the stereoscopic space directly, and for the boy students, they should learn to think over objects with multi-viewpoints. And then the spatial ability on the movement of celestial bodies would be expected to be improved.

• PNF and Movement
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• v.18 no.2
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• pp.255-263
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• 2020

Purpose: The purpose of this study was to investigate the effect of proprioceptive neuromuscular facilitation (PNF) lower extremity pattern on the dominant leg on muscle activity of the lower extremity supported by the ground. Methods: The subjects were 20 healthy males living in Busan. All subjects performed four direction PNF lower extremity patterns, and data were collected by surface electromyography from the gluteus medius (GM), tensor fascia latae (TFL), vastus medialis oblique (VMO), vastus lateralis oblique (VLO), and semitendinosus (STD) muscles of the opposite lower extremity during PNF lower extremity pattern. The PNF lower extremity pattern applied to the dominant leg was (1) flexion/adduction/external rotation with knee flexion; (2) extension/abduction/internal rotation with knee extension; (3) flexion/abduction/internal rotation with knee flexion; and (4) extension/adduction/external rotation with knee extension pattern, repeated 3 times per pattern and using the average value of the collected results. Collected muscle activity values were analyzed by one-way ANOVA, and post-hoc Tukey testing was performed to check between-group differences. The statistical significance level was set at α = 0.05. Results: GM and TFL flexion/abduction/internal rotation pattern with knee flexion was significantly higher than other patterns. VMO and VLO extension/adduction/external rotation pattern with knee extension was significantly higher than other patterns. STD flexion/adduction/external rotation pattern with knee flexion was significantly higher than other patterns. Conclusion: The study confirms differences in lower extremity muscle activity for the PNF lower extremity pattern, indicating that selective muscle contraction induction is possible using a pattern appropriate to the purpose of treatment.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.85-95
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• 2005

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle during One Hand Backhand Stroke and Two Hand Backhand in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head direction were defined. 1. In three dimensional maximum linear velocity of racket head the X axis and Y axis(horizontal direction) showed $-11.04{\pm}2.69m/sec$, $-9.31{\pm}0.49m/sec$ before impact, the z axis(vertical direction) maximum linear velocity of racket head did not show at impact but after impact this will resulted influence upon hitting ball. It could be suggest that Y axis velocity of racket head influence on ball direction and z axis velocity influence on ball spin after impact. The stance distance between right foot and left foot was mean $75.4{\pm}5.86cm$ during one hand backhand stroke and $72.6{\pm}4.67cm$ during two hand backhand stroke. 2. The three dimensional anatomical angular displacement of trunk in interna rotation-external rotation showed most important role in backhand stroke. and is follwed by flexion-extension. the three dimensional anatomical angular displacement of trunk did not show significant difference between one hand backhand stroke and two hand backhand stroke but the three dimensional anatomical angular displacement of trunk was bigger than one hand backhand stroke. 3. while backhand stroke, the flexion-extension and adduction-abduction of right shoulder joint showed significant different between one hand backhand stroke and two hand backhand stroke. the three dimensional anatomical angular displacement of right shoulder joint showed more flex and abduct in one hand backhand stroke. 4. The three dimensional anatomical angular displacement of left shoulder showed flexion, adduction, and external rotation at impact. after impact, The angular displacement as adduction-abduction of left shoulder changed motion direction as abduction. angular displacement of left shoulder as flexion-extension showed bigger than the right shoulder.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.540-545
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• 2016

Many golf balls have wrong rotation axis owing to bad production and scratch. A flying golf ball makes sliced or curved motion mainly to owing the wrong rotation axis of golf ball. Dimples of golf ball make a golf ball higher and more straight flying. When we hit a golf ball by driver or iron club, the dimpled ball flies straight and rotates as well. While the ball flying, the rotating axis of the ball convergence. And this makes the ball motion curved. If we hit a golf ball in direction of the rotation axis, the flying ball makes straight motion. In this paper, we develop a control system to detect convergence axis and time of flying golf ball based on vision system. To show validity of the developed system, We experimented several case for dimpled golf balls.