• Physical Therapy Rehabilitation Science
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• v.5 no.2
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• pp.84-88
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• 2016

Objective: Generally, it is known that there is a correlation between excessive calcaneus eversion and a patient with low back pain and it also affects pelvic alignment. However, there are not enough studies that show calcaneal eversion having an effect on the alignment of the trunk. Design: Cross-sectional study. Methods: A 3-dimensional motion analysis system was used to assess the lower limbs, pelvic alignment, and trunk alignment with increased unilateral and bilateral calcaneal eversion in twenty-one subjects. All subjects were asked to maintain a static posture for seven seconds on a wedge three times per posture for measurement and analysis purposes. The wedge used in the process was a lateral wedge with a 10-degree tilt to the lateral direction. To unify all of the subjects' foot position, the front and inner side of the wedge were marked. The height of the tilted wedge's inner side and flat wedge were balanced equally in order to be able to maintain the lateral part of the foot to the same height when producing an increased calcaneal eversion. Results: Comparing the changes in trunk and pelvic alignment in accordance to calcaneal eversion for each posture, there was a significant different in the X and Y-axis for each posture, but not in the Z-axis (p<0.05). Thus, it can be confirmed that calcaneal eversion in the sagittal plane and frontal plane may have and effect on the pelvis and the trunk. Conclusions: Postures with increased bilateral and unilateral calcaneal eversion has an effect on pelvic alignment, but does not cause any changes in trunk alignment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2001.11b
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• pp.103-106
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• 2001

본 논문에서는 MPEG2비디오 스트림에서 직접 얻을 수 있는 정보들을 활용하여 카메라의 움직임을 추정하여 이를 기반으로 하여 움직이는 객체를 추정하고자 한다. 이를 위해, 먼저 MPEG2의 움직임 벡터는 압축의 효율성 때문에 움직임의 예측이 순서적이지 못한데, 예측 프레임들의 속성을 이용하여 이를 광 플로우(Optical Flow)를 갖는 움직임 벡터(Motion Vector)로 변환하였다. 그리고 이러한 벡터들을 이용하여 카메라의 기본적인 움직임인 팬(Fan), 틸트(Tilt). 줌(Zoom) 등을 정의하였다. 이를 위하여 팬, 틸트-줌 카메라 모델의 매개변수와 같은 의미의 $\Delta$x, $\Delta$y, $\alpha$값을 정의하고자 움직임 벡터 성분의 Hough변환을 이용하여 $\Delta$x, $\Delta$y, $\alpha$값들을 구하였다. 또한 이러한 카메라 움직임(Camera Operation)은 시간적으로 연속적으로 발생하는 특징을 이용하여 각 프레임마다 구한 카메라의 움직임을 보정하였다. 마지막으로 움직이는 객체의 추정은 우선 사용자가 원하는 객체를 바운딩박스 형태로 정의한 후 카메라 움직임이 보정된 객체의 움직임 벡터를 한 GOF(Group of Pictures) 단위로 면적 기여도에 따라 누적하여 객체를 추적하고 해석하였으며 DCT 질감 정보를 이용하여 객체의 영역을 재설정 하였다. 물론 압축된 MFEG2비디오에서 얻을 수 있는 정보들은 최대 블록 단위이므로 객체의 정의도 블록단위 이상의 객체로 제한하였다. 제안된 방법은 비디오 스트림에서 직접 정보를 얻음으로써 계산속도의 향상은 물론 카메라의 움직임특성과 움직이는 객체의 추적들을 활용하여 기존의 내용기반의 검색 및 분석에도 많이 응용될 수 있다. 이러한 개발 기술들은 압축된 데이터의 검색 및 분석에 유용하게 사용되리라고 기대되며 , 특히 검색 툴이나 비디오 편집 툴 또는 교통량 감시 시스템, 혹은 무인 감시시스템 등에서 압축된 영상의 저장과 빠른 분석을 요구시 필요하리라고 기대된다.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.3
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• pp.49-54
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• 2016

PURPOSE: This study was implemented to measure the muscle activity of muscles surrounding shoulder during push-up exercise according to the slope angle. METHODS: This study has research subject consisting of 25 normal male adults without neurologic or musculoskeletal injury in shoulder part. EMG was used as a tool for measuring muscle activity and four muscles including upper trapezius (UT), middle trapezius (MT), Lower Trapezius (LT), and Serratus Anterior (SA) were chosen for measuring the muscle activity of muscles surrounding shoulder. Tilting table slope was set at $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$ and push-up motion was performed three time for each case to use the average value. The measured value was used after generalization process to create %RVC value where the measured value was standardized by using $0^{\circ}$ as a standard. RESULTS: There was a difference of muscle activity according to the tilting table slope during push-up exercise. In UT, MT, and SA, there was no significant $0^{\circ}$ and $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$. But there was significant $30^{\circ}$ and $45^{\circ}$. LT was significant difference between $45^{\circ}$ and $60^{\circ}$ (p<.05). CONCLUSION: There are cases where push-up exercise should be selectively implemented due to shoulder problems. According to this results between $0^{\circ}$ and $30^{\circ}$, push up will be able to more effectively exercise. Applying proper angle of tilting table for push-up to patients who have difficulties in performing motions along with physical consumption can deliver effective and easy exercise program.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.269-279
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• 2011

This study was analyzed the characteristics on the stability of posture while conducting a through two and half rotation technic of pench$\acute{e}$ in rhythmic gymnastics. Two rhythmical gymnastics player(LKH and SSJ) who is a member of the national team were selected, and for obtain the kinematic and kinetic variables were used a ProReflex MCU 240 infrared camera(Qualisys, Sweden) and a Type9286A force platform(Kistler, Switzerland). The mechanical factors were computed by using Visual3D program and Matlab R2009a. During the landing and rotation phase the results showed following characteristics; 1) In medial-lateral and horizontal displacement of the support foot, LKH showed smaller movement than SSJ, but SSJ showed smaller movement than LKH in swing foot. LKH showed bigger movement in medial-lateral axis of COP and vertical axis of COG, but SSJ showed bigger movement in horizontal axis of COP and medial-lateral axis of COG. 2) SSJ showed bigger maximum horizontal and vertical velocity at P1 and P2 than LKH. 3) In the inclination angle of COP and COG, SSJ showed smaller change than LKH, but within medial-lateral tilt of the shoulder, LKH performed rotation motion in horizontal position than SSJ. There was no differences in each force components during rotation, but on landing phase, the results showed a characteristic that SSJ exerted bigger breaking force and vertical force than LKH.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.11
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• pp.98-105
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• 2010

In this paper, double ball-bar is used to estimate the geometric errors of a rotary table, which includes one-axial motion, two-radial motions and two-tilt motions, except the angular positioning error. To simplify the measurement procedures, three measurement steps have been designed and developed. At each measurement step, one end of the double ball-bar is fixed at the nose of spindle and the other end is located on the rotary table. And specific circular test path is planned to keep the distance between two balls as constant at ideal case. The relationship including the geometric errors of a rotary table and the measured distance between two balls which is distorted by the geometric errors is defined by using ball-bar equation. Each geometric error is modeled as $4^{th}$ order polynomial considering $C^1$-continuity. Finally the coefficients of polynomial are calculated by least-square method. Simulation is done to check the validation of the suggested method considering set-up errors and measurement noise. Suggested method is applied to estimate geometric errors of a rotary table of a 5-axis machine tool.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1463-1471
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• 2012

In this study, a 3-axis camera system design is proposed for application to an existing 2-axis surveillance robot. A camera-image-based target-tracking algorithm for this robot has also been proposed. The algorithm has been validated using a virtual simulation. In the algorithm, the heading direction vector of the camera system in the mobile surveillance robot is obtained by the position error between the center of the view finder and the center of the object in the camera image. By using the heading direction vector of the camera system, the desired pan and tilt angles for target-tracking and the desired roll angle for the stabilization of the camera image are obtained through inverse kinematics. The algorithm has been validated using a virtual simulation model based on MATLAB and ADAMS by checking the corresponding movement of the robot to the target motion and the virtual image error of the view finder.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.165-172
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• 2006

The purpose of this study was to determine effects of 12-week wearing of unstable shoe on the standing posture and gait mechanics. Nine healthy men were asked to wear the unstable shoes for 12-week and walk for 30 minute everyday. Their standing posture and gait mechanics were measured before and after treatment. Standing posture was measured for each side(anterior, posterior, lateral) for standing position. And gait analysis was measured joint angle of a right lower limb between first right heel contact and second right heel contact. Kinematic data were collected using video camera at 30 frame per seconds. Statistical analysis was paired t-test(p<.05) to compare before training with after that. A head tilt angle was significantly decreased for posterior side(p<.05). The angle of between center of line and surface was significantly decreased at midstance and take off during walking(p<.05). Ankle dorsiflexion significantly increased at heel contact2(p<.05) and ankle plantarflexion significantly increased at midstance and midswing(p<.05). The increase of ankle dorsiflexion showed that our results consisted with previous study. In conclusion, there was not large significant difference in static standing posture but joint angle of lower limb represented many changes with increasing of ankle motion during walking. These were of benefit to body by increasing leg muscle activity but it was necessary for man having a ankle problem to consider. Further studies concerning optimum outsole angle of unstable shoes are necessary.

• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.51-61
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• 2020

Objective: The purpose of this study is to analyse and comparison the differences of kinematic variables for Fente skill in Fencing. Method: For this, 15 people were selected as 5 beginners with less than 2 years of experience, 5 intermediate-class people with more than 2 years and less than 4 years, and 5 experts-class people with more than 4 years. Through the comparison of Marche Fente motion according to proficiency, for the necessary time, travel distance, the kinematical factor of joint angle, oneway ANOVA was performed in order to identify differences according to variables by phase. Results: The time required for each phase was shown to be shorter for all phases experts than for beginners and intermediates. At the horizontal displacement of the foot, the right foot left out the last phase and the experts appeared long. The left foot showed short beginners in all phases. The angle of forward lean showed that the angle of forward lean was tilted forward by the experts of all phases. There was a difference between the left and right joint angles of the lower limb, both of the ankle, knee and hip joints. Conclusion: In overall, Beginners should quickly widen the distance of their feet when they make a Fente movement. The beginner shall tilt the upper body forward in order to increase the angle of forward lean. The beginner shall, in the last phase, have a smaller angle on the hip joint.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1202-1205
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• 2005

This paper describes a method for vision-based person identification that can detect, track, and recognize person from video using multiple cues: height and dressing colors. The method does not require constrained target's pose or fully frontal face image to identify the person. First, the system, which is connected to a pan-tilt-zoom camera, detects target using motion detection and human cardboard model. The system keeps tracking the moving target while it is trying to identify whether it is a human and identify who it is among the registered persons in the database. To segment the moving target from the background scene, we employ a version of background subtraction technique and some spatial filtering. Once the target is segmented, we then align the target with the generic human cardboard model to verify whether the detected target is a human. If the target is identified as a human, the card board model is also used to segment the body parts to obtain some salient features such as head, torso, and legs. The whole body silhouette is also analyzed to obtain the target's shape information such as height and slimness. We then use these multiple cues (at present, we uses shirt color, trousers color, and body height) to recognize the target using a supervised self-organization process. We preliminary tested the system on a set of 5 subjects with multiple clothes. The recognition rate is 100% if the person is wearing the clothes that were learned before. In case a person wears new dresses the system fail to identify. This means height is not enough to classify persons. We plan to extend the work by adding more cues such as skin color, and face recognition by utilizing the zoom capability of the camera to obtain high resolution view of face; then, evaluate the system with more subjects.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.139-147
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• 1999

In this paper, we present the new angular velocity pick-off method for DTG (dynamically tuned gyroscope) which is widely used in various inertial navigation systems and motion control systems. In case of the external angular velocity input, the proposed scheme can make a smaller tilt-angle rather than that of conventional PI method in the transient and steady state because it has an additional inner rebalance loop with a mathematical model of the real gyroscope. So, without any mechanical redesign of the DTG, its dynamic range can be enlarged by the proposed method. The theoretical analysis and simulation model of DTG with the proposed scheme are given. Finally, the proposed scheme is verified.