• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.935-940
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• 2002

For robot navigation and visual reconstruction, structure from motion (SFM) is an active issue in computer vision community and its properties arc also becoming well understood. In this paper, when using stereo image sequence and direct method as a tool for SFM, we present a new method for overcoming bas-relief ambiguity. We first show that the direct methods, based on optical flow constraint equation, are also intrinsically exposed to such ambiguity although they introduce robust methods. Therefore, regarding the motion and depth estimation by the robust and direct method as approximated ones. we suggest a method that refines both stereo displacement and motion displacement with sub-pixel accuracy, which is the central process f3r improving its ambiguity. Experiments with real image sequences have been executed and we show that the proposed algorithm has improved the estimation accuracy.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.65-72
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• 2018

The purpose of this study was to assess the intra-tester and inter-tester reliability and validity of elbow flexion range of motion using a smart phone used by the general public. Thirty-one general people participated in this study. The range of motion in active elbow flexion was measured with a goniometer and smart phone over two times by two observers. The intra-taster and inter-tester reliability were evaluated using the intraclass correlation coefficient(ICC). The validity was measured by Pearson's correlation coefficient. The intra-observer reliability was good in all measured items ICC>0.900. The inter-observer reliability was high with ICC>0.806. All correlation coefficients of android app and goniometer were greater than 0.868 and showed a significant positive correlation (p<0.01). The range of motion measurement with a smart phone showed acceptable reliability. Therefore, using a smartphone to measure the range of motion of the elbow joint could provide convenience and economic benefits.

• Clinics in Shoulder and Elbow
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• v.7 no.1
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• pp.41-45
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• 2004

In adhesive capsulitis of the shoulder of no response to nonoperative treatment, an arthroscopic capsular release and manipulation improves range of motion and pain relief. We performed an arthroscopic examination in the stiff shoulder, of which she had no response to nonoperative treatment, after the conservative treatment of a clavicular shaft fracture by motorcycle-driver traffic accident. We found the intra-articular 'rotator interval bridging scar adhesion' between subscapularis tendon and antero-superior glenoid fossa under the rotator interval which was no adhesion and contracture itself. We performed the scar adhesion removal and synovectomy, maintaining the rotator interval. We recommended nonsteroidal anti-inflammatory drug for postoperative pain relief and continuous active and passive range of motion (ROM) exercise to gain motions. Preoperatively, active and passive range of motion were 70° for forward elevation, 60° for abduction and especially 0° for external rotation. After postoperative 2 months, active ROM were 150° for forward elevation, 130° for abduction and 80° for external rotation. After postoperative 6 months, passive and active ROM were full. UCLA score improved from preoperative 9 points to postoperative 29 points.

• Physical Therapy Korea
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• v.25 no.1
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• pp.47-52
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• 2018

Background: A limited hip rotational range of motion (ROM) has been considered to be one of characteristics of low back pain (LBP) in athletes. Although LBP frequently occurs in jiu-jitsu athletes, no previous has compared hip rotational ROM between jiu-jitsu athletes with and without LBP. Objects: The aim of the study was to compare ROM for hip internal rotation (IR) and external rotation (ER), and total hip rotation between jiu-jitsu athletes with and without LBP. Methods: Jiu-jitsu athletes were recruited for the LBP group ($n_1=15$) and control group without LBP ($n_2=15$). IR, ER, and total rotational range of hip joint were measured using a goniometer. Analysis of variance was used to compare the ROM between groups and sides. Results: The LBP group showed a significantly lower range of passive hip IR, passive total rotation, active IR, active ER, and active total rotation than the control group (p<.05). Dominant side of passive hip IR and active IR had a significantly lower ROM than non-dominant side (p<.05). In passive ER ROM, non-dominant side was significantly greater than dominant side (p<.05). Conclusion: Compared to jiu-jitsu athletes without LBP, athletes with LBP exhibit a loss of hip rotational ROM. Based on these results, clinicians and athletic trainers should measure hip rotational ROM when designing the management plan for jiu-jitsu athletes with LBP.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1333-1337
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• 2000

The flexural vibration of laminated composite beams with active and passive constrained-layer damping has been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated beams. The damping ratio and modal damping of the first bending mode are calculated by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations with active control.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.70-73
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• 2010

In order to provide theoretical analysis for the active roll stabilizer (ARS), the simulation model based on AMESim is developed in the paper. The simplified vehicle rolling motion model is derived firstly, and then the entire ARS control system model is constructed. Furthermore, the simulation is implemented to confirm the roll control effect. The simulation results show that the derived model can be used as theoretical analysis for developing components of ARS control system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.6
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• pp.408-414
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• 2004

In this paper, a disturbance observer based sliding mode control is proposed to attenuate disturbance responses in an active magnetic bearing system, which is subject to base motion. An algorithm which decouples disturbance observation dynamics from sliding mode dynamics is suggested. This algorithm preserves the robustness of the sliding mode control and satisfies reachability condition in the presence of external disturbance and parameter uncertainties. Along with experimental results, it is shown that the proposed control is effective in disturbance rejection without any additive disturbance measurement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.345-350
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• 1996

The suspension system plays an important role in vehicle performance. To improve suspension characteristics related to riding comfort and handling stability simultaneously, active suspension system is developed. In this study, a hybrid control scheme is proposed, the idea of which is that the sliding mode control is applied to nonlinear hydraulic system and the skyhook control is applied for controlling the motion of the suspension system. The performance of the proposed control method is evaluated by simulation and experiment of a half car active suspension system.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.73-82
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• 2010

The purpose of this study is to understand motion characteristics of older drivers during reaching seat belt compared to young drivers and to provide design guidelines in order to reduce discomfort for the elderly. The whole body kinematics of each subject was captured using 12-camera motion analysis system. Subjective ratings on discomfort levels were obtained simultaneously using a questionnaire. This paper first presents the result of motion characteristics of elderly drivers' reach motion to seat belt. Compared to young drivers, older drivers performed seat belt reach motions less efficiently and moved slower due to mostly the movement error. Older drivers also made use of reduced joint range of motion in cervical left rotation, lumbar left rotation and right shoulder adduction, which can be explained by their reduced active range of motions (AROMs). To compensate for their reduced joint range of motion, older drivers rotated pelvis more.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.314-323
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• 1999

This paper introduces a methodology of active calibration of a camera pose (orientation and position) using the images of cylindrical objects that are going to be manipulated. This active calibration method is different from the passive calibration where a specific pattern needs to be located at a certain position. In the active calibration, a camera attached on the robot captures images of objects that are going to be manipulated. That is, the prespecified position and orientation data of the cylindrical object are transformed into the camera pose through the two consecutive image frames. An ellipse can be extracted from each image frame, which is defined as a circular-feature matrix. Therefore, two circular-feature matrices and motion parameters between the two ellipses are enough for the active calibration process. This active calibration scheme is very effective for the precise control of a mobile/task robot that needs to be calibrated dynamically. To verify the effectiveness of active calibration, fundamental experiments are peformed.