• Journal of IKEEE
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• v.20 no.4
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• pp.344-350
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• 2016

In this Paper, we propose an optimized method of hardware design based on Field Programmable Gate Array (FPGA) to detect rotated angle of high definition image about Extreme Contour Point (ECP) algorithm with moving video image could be not happened to translation motion, but also physical rotation motion. It was evaluated by XC7Z020 xc7z020-3clg400 FPGA board by using xilinx 14.2 tool. The much well-known method, the Coordinate Rotation Digital Integrated Computation (CORDIC) is an algorithm to estimate rotated angle between point and point. Through the result both ECP and CORDIC, our proposed design are confirmed to have similar operating speed of about 4ns with CORDIC. However, it is verified to have high performance result in terms of the hardware cost, is much better than CORDIC with cost reduction of registers and Look Up Tables (LUTs) of 108% and 91%, respectively.

• The KIPS Transactions:PartB
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• v.12B no.5 s.101
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• pp.527-534
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• 2005

Rotation and scale variations make it difficult to solve the problem of shape description and recognition because these variations change the location of points composing the shape. However, some geometric Invariant points and the relations among them are not changed by these variations. Therefore, if points in image space depicted with the r-y coordinates system can be transformed into a new coordinates system that are invariant to rotation and scale, the problem of shape description and recognition becomes easier. This paper presents a shape description method via transformation from the image space into the invariant feature space having two axes: representing relative distance from a centroid and contour segment curvature(CSC). The relative distance describes how far a point departs from the centroid, and the CSC represents the degree of fluctuation in a contour segment. After transformation, mesh features were used to describe the shape mapped onto the feature space. Experimental results show that the proposed method is robust to rotation and scale variations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.94-102
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• 2004

An experimental study on a rotating turbine is conducted with various incidence angles in order to find an optimum incidence angle. The incidence angle is an important design parameter in turbine blade design. however, most of experiments were conducted in a linear or annual cascade row. The suggested incidence angles from the experiments conducted in cascade rows could be unsuitable as a design parameter in the design of rotating parts. In this study, various incidence angles are applied and the turbine performance is measured in a rotating state. Experimental results show that the incidence on the rotor has a great influence on the turbine efficiency. The range of applicable incidence becomes narrow when the turbine operates at high input power. In the case of the tested rotor, the optimum incidence is about $-12^{\circ}$.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.748-754
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• 2010

To reduce the computational cost required for assembling vessel fragments using surface geometry, this paper proposes a fast axis estimation method. Using circular constraint of pottery and local planar patch assumption, it finds the axis of the symmetry. First, the circular constraint on each cylinder is used. A circular symmetric pot can be thought of unions of many cylinders with different radii. It selects one arbitrary point on the pot fragment surface and searches a path where a circumference exists on that point. The variance of curvature will be calculated along the path and the path with the minimum variance will be selected. The symmetric axis will pass through the center of that circle. Second, the planar patch assumption and profile curve is used. The surface of fragment is divided into small patches and each patch is assumed as plane. The surface normal of each patch will intersects the axis in 3D space since each planar patch faces the center of the pot. A histogram method and minimization of the profile curve error are utilized to find the probability distribution of the axis location. Experimental results demonstrate the improvement in speed and robustness of the algorithms.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.100-108
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• 2008

This paper proposes a method of adaptively generating a gait pattern of biped robot. The gait synthesis is based on human's gait pattern analysis. The proposed method can easily be applied to generate the natural and stable gait pattern of any biped robot. To analyze the human's gait pattern, sequential images of the human's gait on the sagittal plane are acquired from which the gait control values are extracted. The gait pattern of biped robot on the sagittal plane is adaptively generated by a genetic algorithm using the human's gait control values. However, galt trajectories of the biped robot on the sagittal Plane are not enough to construct the complete gait pattern because the bided robot moves on 3-dimension space. Therefore, the gait pattern on the frontal plane, generated from Zero Moment Point (ZMP), is added to the gait one acquired on the sagittal plane. Consequently, the natural and stable walking pattern for the biped robot is obtained.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.4
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• pp.48-55
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• 2008

In this paper, numerical analysis of the surface gas temperature on turbine blades has been performed to investigate the temperature profiles characteristics of a partial admission supersonic turbine driven by high temperature and pressure gas of pyro-starter with two different types of turbine blade edge shape. In order to examine the surface gas temperature on turbine blades at initial starting, computations tlave been carried out at several turbine rotational speeds in the range of $0{\sim}10,000$ rpm for each type of turbine edge shape. "Sharp" edge and "Round" edge types were taken as the turbine edge shape factor. As turbine rotational speed increased, the average temperature of turbine blades was further decreased. It was also found that the surface temperature of turbine blades with a sharp edge was lower than round-type edge turbine blades.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.463-463
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• 2010

고휘도 고효율 백색 LED (lighting emitting diode)가 차세대 조명광원으로 급부상하고 있다. 백색 LED를 생산하기 위한 공정에서 MOCVD (유기금속화학증착)장비를 이용한 Epi wafer공정은 에피층과 기판의 격자상수 차이와 열팽창계수차이로 인하여 생성되는 에피결함의 제거를 위하여 기판과 GaN 박막층 사이에 완충작용을 해줄 수 있는 버퍼층 (Buffer layer)을 만들고 그 위에 InGaN/GaN MQW (Multi Quantum Well)공정을 하여 고휘도 고효율 백색 LED를 구현할 수 있다. 이 공정에서 기판의 온도가 불균일해지면 wafer 파장 균일도가 나빠지므로 백색 LED의 yield가 떨어진다. 균일한 기판 온도를 갖기 위한 조건으로 기판과 induction heater의 간격, 가스의 흐름, 기판의 회전, 유도가열코일의 디자인 등이 장비의 설계 요소이다. 코일에 교류전류를 흘려주면 이 코일 안 또는 근처에 있는 도전체에 와전류가 유도되어 가열되는 유도가열 방식은 가열 효율이 높아 경제적이고, 온도에 대한 신속한 응답성으로 인하여 열 손실을 줄일 수 있으며, 출력 온도 제어의 용이성 및 배출 가스 등의 오염 없다는 장점이 있다. 본 연구에서는 유도가열방식의 induction heater를 이용하여 회전에 의한 기판의 온도 균일도 측정을 하였다. 기초 실험으로 저항 가열 히터를 통하여 대류에 의한 온도 균일도를 평가하였다. 그 결과 gap이 3 mm일 때, 평균 온도 $166.5^{\circ}C$ 에서 불균일도 6.5 %를 얻었으며 이를 바탕으로 induction heater와 graphite susceptor의 간격이 3 mm일 때, 회전에 의한 온도 균일도를 측정을 하였다. 가열원은 induction heater (viewtong, VT-180C2)를 사용하였고, 가열된 graphite 표면의 온도를 2차원적으로 평가하기 위하여 적외선 열화상 카메라(Fluke, Ti-10)을 이용하여 온도를 측정하였다. 기판을 회전하면서 표면 온도의 평균과 표준 편차를 측정한 결과 2.5 RPM일 때 평균온도 $163^{\circ}C$ 에서 가장 좋은 5.5 %의 불균일도를 확인할 수 있었고, 이를 상용화 전산 유체 역학 코드인 CFD-ACE+의 모델링 결과와 비교 분석 하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.137-142
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• 2021

In recent years, permanent magnets such as IPM (Interior Permanent Magnet) motors or SPM (Surface Permanent Magnet) motors that can obtain high efficiency and power density by inserting rare earth permanent magnets into the rotor are used. Research on the used electric motor is being actively conducted. Since it uses a permanent magnet, it has the advantage of high efficiency and high power density compared to reluctance motors and induction motors, but by inserting a permanent magnet into the rotor, it operates at high speeds and decreases reliability due to demagnetization of the permanent magnets, and increases the cost of rare earth metals. In this paper, in accordance with the development of future technology that can replace rare-earth permanent magnet motors and technological preoccupation of rare-earth reduction type motors and de-rare-earth motors, switched reluctance motors that do not require permanent magnets (Switched Reluvtance Motors) Motor, SRM) to drive driving control. Using the 3-phase SRM library provided by the PSIM simulation program, we will study the driving and control system modeling of SRM using the rotor position information sensor.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.423-432
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• 2018

The purpose of this study was to investigate the differences in upper and lower strengths and symmetry between upper body injury group, lower body injury group and non-injury group of bowling athletes. The subjects were the upper body injury group (UG), n = 16, the low body injury group (LG), n = 8, the non injury group, [NG], n = 15). The isometric strength of the bowler was measured using Manual Muscle Tester 01165 (Lafayette Instrument Company, USA) and the symmetry index (SI) was calculated. The results were as follow. The symmetry index of hip extension strength and hip external rotation strength was statistically larger in NG than LG (p <.05). The above results suggest that lower body strength and bilateral symmetry was closely related to injuries of the lower body. In order to prevent injury of the bowler, strengthening of lower body strength and symmetrical training are needed.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.90-95
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• 2008

Purpose: We wanted to assess the accuracy of ultrasound for detecting abnormality of the long head of the biceps tendon in patients with rotator cuff disorders. Materials and Methods: Between January 2006 and March 2007, we reviewed the arthroscopic findings of biceps tendons in 67 patients with rotator cuff disorder and who underwent ultrasonography pre-operatively. The patients' average age was 58 years and there were 41 males and 26 females. The statuses of the biceps tendons were described as 'normal', 'dislocation', 'subluxation', 'partial or complete tears', and 'tendinopathy'. We investigated the correspondence between the arthroscopic and ultrasonographic findings. Results: On ultrasonography, the biceps tendons were 'normal' in 37 patients and 'abnormal' in 30 patients. On arthroscopy, 5 biceps tendons turned out to have partial tears, which were 'normal' on ultrasonography. On the other hand, 8 biceps tendons were 'normal' which were 'abnormal' on ultrasonography. Three dislocations and 4 complete tears of biceps tendons were identified on arthroscopy, and all of them were detected by ultrasonography. Of the 20 cases of 'tendinopathy' seen on ultrasonography, 15 patients had partial tears and the remaining 5 patients were normal on arthroscopy. Conclusion: Ultrasonography is accurate for detecting some biceps pathologies, such as dislocation or complete tear, but it is not accurate for the detection of partial tear.