• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1155-1166
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• 2016

In this paper, we propose a new embedded video compression scheme which uses three-dimensional rate-distortion optimization based block coder. After the proposed scheme removes temporal redundancy by applying the motion compensated temporal filtering(MCTF) on input video frames, two dimensional discrete wavelet transform is applied on video frames to remove spatial redundancy. The three-dimensional wavelet coefficients generated in this way are sorted according to their expected rate-distortion slope and encoded by using the three-dimensional block partition coding method. The proposed scheme also uses both the effective color video coding method which maintains embedded features, and the efficient bit-rate control method. Experimental results demonstrate that the proposed scheme not only produces embedded bit-streams, but also outperforms existing video compression schemes.

• Physical Therapy Korea
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• v.13 no.2
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• pp.61-69
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• 2006

The purpose of this study was to compare the electromyography (EMG) activities of the lumbar extensor muscles during motion of trunk flexion-extension and compare range of motion (ROM) with a 3-dimensional motion analysis system of the lumbar region between subjects with chronic low back pain (CLBP) and healthy subjects during the trunk flexion-extension, trunk rotation and trunk lateral flexion cycle. Thirty CLBP subjects and thirty healthy subjects were included. We measured the root mean square (RMS) value of the lumbar extensor muscles from resting, standing, lumbar flexion and return position. The RMS ratio was normalized from maximal EMG activity of the lumbar extensor muscles during trunk motion. The results of this study showed that the RMS ratio of the lumbar extensor was significantly higher in CLBP subjects than healthy subjects during all of trunk motion (p<.05). The ratio of the highest RMS value during flexion and extension was higher in CLBP subjects than in healthy subjects (p<.05). The ROM of the lumbar region was significantly lower in CLBP subjects than healthy subjects during trunk flexion-extension, trunk rotation and lateral flexion cycle. The relationship between the RMS ratio for full lumbar flexion and the ROM of lumbar flexion was not correlated significantly. CLBP subjects have both decreased ROM of the lumbar region and higher muscle activities of the lumbar extensor muscle than healthy subjects.

• Clinics in Shoulder and Elbow
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• v.26 no.2
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• pp.148-155
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• 2023

Background: Although visual examination and palpation are used to assess shoulder motion in clinical practice, there is no consensus on shoulder motion under dynamic and static conditions. This study aimed to compare shoulder joint motion under dynamic and static conditions. Methods: The dominant arm of 14 healthy adult males was investigated. Electromagnetic sensors attached to the scapular, thorax, and humerus were used to measure three-dimensional shoulder joint motion under dynamic and static elevation conditions and compare scapular upward rotation and glenohumeral joint elevation in different elevation planes and angles. Results: At 120° of elevation in the scapular and coronal planes, the scapular upward rotation angle was higher in the static condition and the glenohumeral joint elevation angle was higher in the dynamic condition (P<0.05). In scapular plane and coronal plane elevation 90°-120°, the angular change in scapular upward rotation was higher in the static condition and the angular change in scapulohumeral joint elevation was higher in the dynamic condition (P<0.05). No differences were found in shoulder joint motion in the sagittal plane elevation between the dynamic and static conditions. No interaction effects were found between elevation condition and elevation angle in all elevation planes. Conclusions: Differences in shoulder joint motion should be noted when assessing shoulder joint motion in different dynamic and static conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.638-643
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• 1993

The three dimensional finite element models for the basic deflection of linear motion guides and ball screws were developed. Form the comparison of the results calculated by the finite element method with those by the experiment, it was proved that the modeling method might be applied to real machine tool structures. Form the structural analysis of the headstock of the machine tool, it was found that the static stiffness was calculated within 6.5% error

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.59-67
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• 2019

Purpose : The purpose of this study was to analyze the dynamic range of motion (ROM) of pelvic and translation of center of mass (COM) when wearing different shoe insole lifts according to leg length discrepancy (LLD) during free speed gait. Methods : Thirty-five healthy adults were participated in this study. Kinematic data were collected using a Vicon motion capture system. Reflective and cluster 40 markers attached to participants lower extremities and were asked to walk in a 6 m gait way under three different shoe lift conditions (without any insole, 1 cm insole, and 2 cm insole). The pelvic ROM and COM translation in three planes were sorted using a Nexus software, and a Visual3D motion analysis software was used to coordinate all kinematic data. Results : There were significantly increased maximal pelvic elevation and total pelvic range in coronal plane when wearing a standard shoe with 2 cm insole lift during gait (p<.05). When wearing a standard shoe with 2 cm insole lift, the total range of the pelvic segment were significantly different in all three motion planes (p<.05). Conclusion : Although LLD of less than 2 cm develops abnormal movement pattern of the pelvis and may cause of musculoskeletal diseases such as low back pain, hip and knee joint osteoarthritis, therefore intensive various physical therapy interventions for LLD are needed.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.132-142
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• 1999

A three-dimensional linearised potential theory is presented for the prediction of motions and dynamic structural responses of twin-hull ships travelling with forward speed in regular waves. Comparisons between theoretical and experimental results are shown for the motion responses and lateral wave loads of an ASR(anti-submarine rescue) catamaran. In general, good agreement between theory and experiment is found except for some discrepancies that are believed to be caused by neglect of forward speed effects on free surface.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.85-89
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• 1997

We used a three-dimensional motion capture method to measure the grasping reach of Korean. This method was applied well to the grasping reach measurement with low measurement error and high efficiency. We measured the grasping reach of 29 males and 21 females at the different height from seat reference level; -10, 0, 30, 60, and 90cm. The grasping reach data were summarized at each 15 .deg. in polar corrdinates to compare with the former researches. If the number of subjects increases in the supplement research, the grasping reach data will be used in the ergonomic design of the driver's cabin or workstations in industry.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.1-9
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• 2006

This paper presents the modeling and multivariable feedback control of a novel high-precision multi-dimensional positioning stage. This integrated 6-degree-of-freedom. (DOF) motion stage is levitated by three aerostatic bearings and actuated by 3 three-phase synchronous permanent-magnet planar motors (SPMPMs). It can generate all 6-DOF motions with only a single moving part. With the DQ decomposition theory, this positioning stage is modeled as a multi-input multi-output (MIMO) electromechanical system with six inputs (currents) and six outputs (displacements). To achieve high-precision positioning capability, discrete-time integrator-augmented linear-quadratic-regulator (LQR) and reduced-order linearquadratic-Gaussian (LQG) control methodologies are applied. Digital multivariable controllers are designed and implemented on the positioning system, and experimental results are also presented in this paper to demonstrate the stage's dynamic performance.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.246-247
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• 2003

Large Eddy Simulation(LES) of turbulent spray combustion flow was conducted. An experimental database for the laboratory spray combustor is chosen to validate the present numerical simulation. The governing equations for the gas phases are discretized in three-dimensional curvilinear boundary-fitted coordinate system, and the fuel droplet motion equations are described in Lagrangian representation. The numerical results are compared with the experiment for the gas-phase mean velocities and its fluctuation in cold flow condition. Three dimensional vortical structures are well visualized and droplet motion is well predicted.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.191-192
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• 2003

A numerical method for a wave diffraction problem in three-dimensional channels is developed. The physical models are various shapes of channel connected to the open sea. When a ship or an offshore structure is moored in various configurations of channel connected to an open sea, the prediction of the hydrodynamic force exerting on the moored ship could be important for the prediction of its motion. It is assumed that the fluid is inviscid and incompressible and its motion is irrotational. From the continuity equation, the Laplace equation can be obtained as the governing equation. The surface tension at free surface is neglected, and wave amplitude is assumed to be small compared to the wave length. Then the free surface condition can be linearized. The numerical method used here is the localized finite element method based on a variational formulation