• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.221-232
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• 2012

The double-density discrete wavelet transform(DWT) is an improvement upon the critically sampled DWT with important additional properties. It employs one scaling function and two distinct wavelets, which are designed to be offset from one another by one half. And it is overcomplete by a factor of two. Also, this transformation is nearly shift-invariant. But there is room for improvement because not all of the wavelets are directional. That is, although the double-density DWT utilizes more wavelets, some lack a dominant spatial orientation, which prevents them from being able to isolate those directions. Proposed method is a DWT that combines the double-density DWT and quincunx sampling, each of which has its own characteristics and advantages. Especially, the quincunx sampling treats the different directions more homogeneously. As a result, since proposed method can generate sub-images of multiple degrees rotated versions, this method provides an improved performance in image processing fields.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.165.2-165.2
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• 2016

빗각 증착이란 입사 증기가 기판에 수직하게 입사하는 일반적인 공정과는 다르게 증기가 기판의 수직선과 $0^{\circ}$이상의 각을 갖는 증착 방법을 의미한다. 본 연구는 공정 압력이 비교적 높은 스퍼터링 공정에서 빗각 증착을 실시하여 코팅층의 구조제어가 가능한지를 확인하였다. 본 연구에서는 조직의 치밀도 향상을 통한 특성 향상을 위해 TiN 박막을 제조함에 있어서 빗각 증착 기술을 응용하여 단층 및 다층 피막을 제조하고 그 특성을 비교하였다. 스퍼터 소스에 장착된 타겟의 크기는 6"이며, 99.5% Ti 타겟을 사용하였고, Ar 가스 분위기에서 기판으로 사용된 Si(100) 위에 코팅하였다. 기판과 타겟 간의 거리는 10 cm이며, 기판은 알코올과 아세톤으로 초음파 세척을 실시한 후 진공챔버에 장착하고 < $2.0{\times}10-5Torr$ 까지 진공배기를 실시하였다. 진공챔버가 기본 압력까지 배기되면 Ar 가스를 주입한 후 RF 파워에 약 300V의 전압을 인가하여 글로우 방전을 발생시키고 약 30분간 청정을 실시하였다. 기판의 청정이 끝난 후 다시 < $2.0{\times}10-5Torr$까지 진공배기를 한 후 Ar 가스를 주입하여 TiN 코팅을 실시하였다. 빗각 증착을 위한 기판의 회전각은 $70^{\circ}$, $80^{\circ}$와 $-70^{\circ}$, $-80^{\circ}$이며, TiN 박막의 총 두께는 약 $3.5{\sim}4{\mu}m$로 유지하였다. 스퍼터링을 이용한 TiN 박막의 빗각 증착 코팅을 실시하였으며, 공정조건에 따라 주상정이 자라는 모습과 기울어진 각도가 다른 구조를 갖는 박막이 제조되는 것을 확인할 수 있었다. 빗각증착을 실시하는 중에 기판 홀더에 약 -100 V의 전압을 인가하면 인가하지 않은 막에 비해 치밀한 박막이 성장한다는 사실을 확인하였다. 박막의 성능향상을 위하여 스퍼터 시스템에서 빗각 증착을 이용한 TiN 박막 형성을 실시하였다. SEM 단면 이미지에서 확인해본 결과 주상정이 자라는 형상이 공정 압력이 5 mTorr에서 2 mTorr로 낮아짐에 따라 상대적으로 치밀하면서 일정한 형태로 성장하는 것을 확인하였다. 본 연구를 통해 스퍼터링을 이용한 빗각 증착의 Structure Engineering 이 가능함을 확인하였으며 박막의 성능을 향상시키는 기술로서 응용 가능할 것으로 보인다.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.364-375
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• 2009

The purpose of this study is to offer basic data for the fall prevention by analyzing the kinematic difference between the lower limb joints and the lower extremities in elderly people's walking given the lower-limb resistance exercises. For this, three-dimensional image analysis was carried out by selecting 7 elderly women from over 70s to under 80 years old. To obtain the three-dimensional location coordinates in the lower limb joints and the lower extremities, it shot with 100Hz/s by using MCU(Qualisys, Sweden) camera. The shot image gained raw data on the location coordinates by using QTM(Qualisys, Sweden). As a result of calculating three-dimensional angle by using program of Matlab 6.5, the following conclusions were obtained. Flexion and extension in the thigh and the lower-leg extremities were indicated to be big in motion of flexion after exercising at E5. Foot segment indicated statistical difference while showing eversion at E4. Knee joints showed flexion at E4 after exercising. Ankle joints showed statistical difference while indicating motion in inversion at E3 and in eversion at E4(p<.05).

• Journal of KIISE:Software and Applications
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• v.30 no.9
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• pp.885-893
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• 2003

In this paper, a new practical implementation of a person verification system using features of longitudinal section and transection and other facial, rotation compensated 3D face image, is proposed. The approach works by finding the nose tip that has a protrusion shape on the face. In feature recognition of 3D face image, one has to take into consideration the orientated frontal posture to normalize. Next, the special points in regions, such as nose, eyes and mouth are detected. The depth of nose, the area of nose and the volume of nose based both on the 3 longitudinal section and a transection are calculated. The eye interval and mouth width are also computed. Finally, the 12 features on the face were extracted. The Ll measure for comparing two feature vectors were used, because it is simple and robust. In the experimental results, proposed method achieves recognition rate of 95.5% for the longitudinal section and transection.

• Physical Therapy Korea
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• v.17 no.1
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• pp.1-8
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• 2010

The purpose of this study was to compare EMG activity for pectoralis major muscle during shoulder movement with various abduction angle and rotation position in supine position. Fifteen healthy subjects were recruited for this study. All subjects performed shoulder horizontal adduction holding a 2 kg dumbbell in shoulder abduction $40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$ with shoulder neutral, internal rotation (IR), and external rotation (ER). Surface EMG activity was recorded from pectoralis major clavicle part and pectoralis major sternum part for 5 seconds and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). Dependent variables were examined with 3 (Neutral, IR, ER) ${\times}$ 5 ($40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$) analysis of variance with repeated measures. The EMG activity of pectoralis major muscle was significantly different between shoulder abduction angles and between shoulder rotation positions (p<.05). The highest value of EMG activity of pectoralis major clavicle part among shoulder abduction angles was in $70^{\circ}C$ and, $90^{\circ}C$ in that order. The highest value of EMG activity of pectoralis major sternum part among shoulder abduction angles was in $130^{\circ}C$ and, $90^{\circ}C$ in that order. According to the rotation degree, shoulder ER showed the highest value and IR showed the lowest value in both muscle parts. These results suggest that shoulder abduction $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$ will be effective during manual muscle testing (MMT) and strengthening exercise for pectoralis major muscle. It is also supposed that shoulder ER is the efficient posture for strengthening of pectoralis major muscle.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1091-1097
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• 2012

Nowadays, some movie theaters provide additional sensory information in 3D movies to enhance visually induced motion perception. However, no studies have investigated how motion perception increases. Thus, in this study, we examined the effect of visual coherent sensory information on visually induced motion perception and quantification of sensory information. A visual stimulus rotated sinusoidally and visual coherent sensory information were applied as vibrations to a subject's foot. We measured the sway of the subject's body by using a force plate and somatosensory bar rotation that represents the subject's perception of the horizon using an encoder. By using this data, we obtained the weight of the sensory information using a Kalman filter. As a result, it was found that subjects rotated the somatosensory bar more when visual coherent vibrations were applied. The weight of vision also increased when visual coherent vibrations were applied. Thus, we can conclude that visual coherent sensory information tends to enhance visually induced motion perception and weight of vision.

• The Journal of Korean Physical Therapy
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• v.24 no.5
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• pp.334-339
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• 2012

Purpose: This study was conducted in order to compare the ability to control postural sway during perturbation when stroke patients received postural sway induced by head rotation. Methods: This study included 15 stroke patients and 15 healthy adults. Each group was measured by 3D motion analysis for determination of the angle of the neck in static position and by balance performance monitor for estimation of swaying angle in both neutral posture and head rotation position. These results were then analyzed in order to compare the healthy control group and the stroke patients group. Results: In both static posture ($60.7{\pm}4.81$) and dynamic posture ($51.46{\pm}6.87$, $70.8{\pm}6.55$), significant decreases were observed in the angle of head rotation of the patient group, compared to the healthy group (p<0.05), and significant decreases were observed in the sway angle of the patient group when in the neutral position ($3.62{\pm}7$, $24{\pm}0.60$) and head rotation ($3.04{\pm}0.80$, $51.46{\pm}6.87$), compared to the healthy group (p<0.05). Conclusion: According to these findings, patients with stroke tend to restrict the ROM of head rotation and swaying angle in dynamic posture and maintain their posture instability using limitation of head movement relative to the trunk and sway angle of area which is larger than that of affected side in unaffected side.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.473-483
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• 2015

This paper reports the single-input-single-output cascade control by using 1-axis attitude control test-bench for quad-rotor UAV. The test-bench was designed as a see-saw shape using 2 motors and propellers, and to enable changing the center of gravity with the center of gyration using ballast. The experiment was carried out by constructing a PID-PID controller having a cascade structure with the test-bench. The SIMC based PID gain tuning process, which makes PID gain tuning easy, was grafted to cascade control. To graft SIMC method, the system parameter estimation result was conducted with second order time delay model by using Matlab-Simulink. Gain tuning was conducted by simulating with estimated system parameter. In this paper, the conventional application of SIMC was conducted and improved application was proposed for improving stability at tuning process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2381-2387
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• 2013

This paper deals with an optimal angle error reduction method of magnetic hall sensor using hall effect elements with yoke. The magnetic position sensor is required to generate ideal sine and cosine waveforms from its hall effect elements according to rotation angle for precise angle information. However, the output signals are easy to include harmonics due to uneven magnetic field distribution from disturbance in the vicinity of hall effect elements. Thus, The paper studies a way which makes sine and cosine waveforms robust in disturbance and reduces harmonics by installing a yoke around Hall effect elements. The angle detection simulation for the magnetic hall sensor is performed by 3 dimensional finite element method and Taguchi method, one of the design of experiments. For the Taguchi method, three design parameters related to position of hall effect elements and shape of hall effect element yoke are selected.

• Korean Journal of Remote Sensing
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• v.27 no.1
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• pp.25-31
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• 2011

Precise control of antenna position is very critical in ArcSAR system which uses an arc-rail as a platform for the antenna movement instead of linear rail. In order to minimize the antenna positional error, we improved the motion driving system and applied a newly developed motion control S/W which utilizes the real time antenna position information from magnetic linear scale and encoder. The experimental results showed that the rotational RMS error was reduced to $0.0062^{\circ}$ from $0.0432^{\circ}$. In terms of antenna positional RMS error for the arm length of 3m, it was reduced to 0.324mm from 2.262mm. It is expected that the ArcSAR system can be used to monitor the sub-millimetric displacement of terrain and structural targets.