• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.177-182
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• 1998

In this paper, we propose a lossless motion video coding method using motion compensation. For realtime coding and transmission, we developed a lossless video codec based on the proposed method. It was confirmed the codec functions normally in an experiment involving coding and transmitting through an actual ATM network. Furthermore, we proposed a lossless coding method with bit-plane expansion under a constant bitrate. Two approaches, a closed bit-plane approach and a merged bit-plane approach, are considered and characteristics of their compression efficiency are estimated. Simulation results show that the proposed method is suitable for lossless video coding with bitrate control.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.36-36
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• 2002

To Establish of standard technique of length measurent in 2D plane, we develope AFM system. The XY scanner scans the sample only in XY plane, while the Z scanner scans the specimen only in Z-direction. Cantilever tip is controlled to has constant height relative to speciman surface by feedback of PSPD signal. To acquire high accuracy, Z-axis measuring sensor will be added.(COXI or others). In this paper we design XYZ stage suitable for this AEM system. For XY stage, single module parallel-kinnematic flexure stage is used which has high orthogonality and minimum out-of-plane motion. To obtain best performance optimal design is performed. For XY stage, to be robust about parasitic motion optimal design of maximizing Z and tilt stiffness is performed under the constraint of motion range and stage size. And for Z stage, optimal design of maximizing 1st resonant frequency is performed. Because if resonant frequency is get higher, scan speed is improved. So it makes reduce the error by sensor drift. Resultly XYZ stage each have 1st natural frequency of 115㎐, 201㎐, 2.66㎑ and range 109㎛, 110㎛, 12㎛.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.193-202
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• 2004

This paper presents a computer method for the dynamic analysis of a system of rigid bodies in plane motion. The formulation rests upon the idea of replacing a rigid body by a dynamically equivalent constrained system of particles. Newton's second law is applied to study the motion of the resulting system of particles without introducing any rotational coordinates. A velocity transformation is used to transform the equations of motion to a reduced set. For an open-chain, this process automatically eliminates all of the non-working constraint forces and leads to an efficient integration of the equations of motion. For a closed-chain, suitable joints should be cut and few cut-joints constraint equations should be included. An example of a closed-chain is used to demonstrate the generality and efficiency of the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.836-839
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• 2005

The in-plane vibration response of a clamped circular plate should be predicted in many applications. Up to now, papers on the in-plane vibration of rectangular plate are published. However, analytical derivation on the in-plane vibration of the clamped circular plate is not carried out. Therefore, the in-plane vibration of the clamped circular plate is the concern of this paper. In order to derive the equations of motion for the clamped circular plate in the cylindrical coordinate, the kinetic energy and potential energy for the in-plane behavior are obtained by us ing the stress-strain-displacement expressions. Application of Hamilton's principle leads to two sets of differential equations. These displacement equations were highly coupled. It is possible to obtain a simpler set of equations by introducing Helmholtz decomposition. Substituting them into the coupled differential equations, we obtain the uncoupled equations of motion. In order to solve them, we assume that the solutions are harmonic. Then, they lead to the wave equations. Using the separation of variable, we obtain the general solutions for the equations. Based on the solutions, the displacements for r and $\theta$ direction are assumed. Finally we obtain the frequency equation for the clamped circular plate by the application of boundary conditions. The derived equation is compared with the finite element analysis for validation by using the some numerical examples.

• Structural Engineering and Mechanics
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• v.42 no.4
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• pp.589-608
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• 2012

In this study, the effect of in-plane deformations on the dynamic behavior of laminated plates is investigated. For this purpose, the displacement-time and strain-time histories obtained from the large deflection analysis of laminated plates are compared for the cases with and without including in-plane deformations. For the first one, in-plane stiffness and inertia effects are considered when formulating the dynamic response of the laminated composite plate subjected to the blast loading. Then, the problem is solved without considering the in-plane deformations. The geometric nonlinearity effects are taken into account by using the von Karman large deflection theory of thin plates and transverse shear stresses are ignored for both cases. The equations of motion for the plate are derived by the use of the virtual work principle. Approximate solution functions are assumed for the space domain and substituted into the equations of motion. Then, the Galerkin method is used to obtain the nonlinear algebraic differential equations in the time domain. The effects of the magnitude of the blast load, the thickness of the plate and boundary conditions on the in-plane deformations are investigated.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.347-358
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• 2009

In this thesis, we develop a vision based hand motion recognition system using a camera with two rotational motors. Existing systems were implemented using a range camera or multiple cameras and have a limited working area. In contrast, we use an uncalibrated camera and get more wide working area by pan-tilt motion. Given an image sequence provided by the pan-tilt camera, color and pattern information are integrated into a tracking system in order to find the 2D position and direction of the hand. With these pose information, we estimate 3D motion plane on which the gesture motion trajectory from approximately forms. The 3D trajectory of the moving finger tip is projected into the motion plane, so that the resolving power of the linear gesture patterns is enhanced. We have tested the proposed approach in terms of the accuracy of trace angle and the dimension of the working volume.

• PNF and Movement
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• v.20 no.3
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• pp.371-381
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• 2022

Purpose: Forward head posture (FHP) is known to cause pain, limit range of motion, and reduce quality of life. Joint mobilization is commonly used to correct FHP. However, no study has compared cervical, thoracic, and combined cervical and thoracic joint mobilization for FHP. The aim of this study was to investigate and compare the effects of each mobilization technique on range of motion in the sagittal plane and pain in patients with FHP. Methods: Forty-five patients were recruited and randomly divided into three groups: the mobilization group (CM; n = 15), the cervical and thoracic mobilization group (CTM; n = 15), and the thoracic mobilization group (TM; n = 15). Each intervention was performed in sets of three and repeated six times. Range of motion and pain were assessed pre- and post-intervention. The cervical range of motion was evaluated using a goniometer, and pain was evaluated using a visual analogue scale and pain thresholds of the suboccipital and upper trapezius muscles. Results: All groups showed an increase in range of motion post-intervention, but the increase in the CTM group was significantly greater than in the CM and TM groups (p < 0.05). Pain measured using the visual analogue scale decreased in all groups, but the decreases in the CM and CTM groups were significantly greater than in the TM group (p < 0.05). The pain thresholds of the suboccipital and upper trapezius muscles increased in all groups, but the increase in the CTM group was significantly greater than in the CM and TM groups (p < 0.05). Conclusion: Overall, our findings suggest that CTM may be more effective than CM or TM for improving cervical range of motion in the sagittal plane and pain in patients with FHP.

• 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.

• Wind and Structures
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• v.26 no.3
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• pp.179-190
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• 2018

Translation of tornadoes is an important feature in replicating the near-ground tornado flow field which has been simulated in previous studies based on Ward-type tornado simulators using relative motion of the ground plane. In this laboratory investigation, effects of translation on the near-ground tornado flow field were studied using the ISU Tornado Simulator that can physically translate over a ground plane. Two translation speeds, 0.15 m/s and 0.50 m/s, that scale up to those corresponding to slowly-moving tornadoes in the field were selected for this study. Compared with the flow field of a stationary tornado, the simulated tornado with translation had an influence on the spatial distribution and magnitude of the horizontal velocities, early reversal of the radial inflow, and expansion of the core radius. Maximum horizontal velocities were observed to occur behind the center of the translating tornado and on the right side of its mean path. An increase in translation speed, resulted in reduction of maximum horizontal velocities at all heights. Comparison of the results with previous studies that used relative motion of the ground plane for simulating translating tornadoes, showed that translation has similar effects on the flow field at smaller radial distances (~2 core radius), but different effects at larger radial distances (~4 core radius). Further, it showed that the effect of translation on velocity profiles is noticeable at and above an elevation of ~0.6 core radius, unlike those in studies based on the relative motion of the ground plane.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.1-6
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• 2004

Measurements of circular motion accuracy of NC lathe have achieved with ball bar systems proposed by Bryan, but the ball bar systems have ifluenced on the measuring data by way of the accuracy of the balls and the contacts of balls and bar seats. Therefore in this study, error data during of circular motion of ATC(Automatic Tool Changer) of NC lathe will be acquired by reading zx plane coordinates using two optical linear scales. Two optical linear scales of measuring unit are fixed on z-x plane of NC lathe, and the moving part is fixed to ATC and then is made to receive data of coordinates of the ATC at constant time intervals using tick pulses comming out from computer. And then, error data files of radial direction of circular motion are calculated with the data read, and the aspect of circular motion are modeled to plots, and are analysed by means of statistical treatments of circularity, means, standard deviations etc.