• Journal of the Korean Statistical Society
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• v.28 no.1
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• pp.1-19
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• 1999

In this paper we establish some limit theorems for a two-parameter fractional Levy Brownian motion on rectangles in the Euclidean plane via estimating upper bounds of large deviation probabilities on suprema of the two-parameter fractional Levy Brownian motion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1471-1481
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• 1998

In this paper, we propose a new digital image stabilization scheme based on the bit-plane matching. In the proposed algorithm, the conventional motion estimation algorithms are applied to the binary images extracted from the bit-plane images. It is shown that the computational complexity of the proposed algorithm can be significantly reduced by replacing the arithmetic calculations with the binary Boolean functions, while the accuracy of motion estimation is maintained. Furthermore, an adaptive algorithm for selecting a bit-plane in consideration of changes in external illumination can provide the robustness of the proposed algorithm. We compared the proposed algorithm with existing algorithms using root mean square error (RMSE) on the basis of the brute-force method, and proved experimentally that the proposed method detects the camera motion more accurately than existing algorithms. In addition, the proposed algorithm performs digital image stabilization with less computation.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.309-312
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• 2000

In this work, a new algorithm for canceling MRI artifact due to translational motion in image plane is described. In the previous approach, the motions in the x direction and the y direction are estimated simultaneously. By analyzing their features, each x and y directional motion is canceled by different algorithms in two steps. First, it is noticed that the x directional motion corresponds to a shift of the x directional spectrum of the MRI signal. Next, the y directional motion is canceled by using a new constraint condition. This algorithm is shown to be effective by using a phantom image with simulated motion.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.1
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• pp.49-57
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• 2000

In this study, a new algorithm for canceling a MRI artifact due to the translational motion In the image plane is described. Unlike the conventional iterative phase retrieval algorithm, in which there is no guarantee for the convergence, a direct method for estimating the motion is presented. In previous approaches, the motions in the x(read out) direction and the y(phase encoding) direction were estimated simultaneously. However, the feature of x and y directional motions are different from each other. By analyzing their features, each x and y directional motion is canceled by the different algorithms in two steps. First, it is noticed that the x directional motion corresponds to a shift of the x directional spectrum of the MRI signal, and the non-zero area of the spectrum just corresponds to the projected area of the density function on the x axis. So the motion is estimated by tracing the edges between non-zero area and zero area of the spectrum, and the x directional motion is canceled by shifting the spectrum in an reverse direction. Next, the y directional motion is canceled by using a new constraint condition, with which the motion component and the true image component can be separated. This algorithm is shown to be effective by using a phantom image with simulated motion.

• The Journal of the Acoustical Society of Korea
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• v.17 no.2E
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• pp.47-52
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• 1998

An analysis of dynamic responses is carried out on monoclinic anisotropic system due to a buried harmonic line source. The load is in the form of a normal stress acting along an arbitrary axis on the plane of symmetry within the orthotropic materials: In case that the line load is acting along the symmetry axis normal to the plane of symmetry, plane wave equation is coupled with verital shear wave and longitudinal wave. However, if the line load is acting along an arbitrary axis normal to the plane of symmetry, plane wave equation is coupled with vertical shear wave, longitudinal wave and horizontal shear wave. We first considered the equation of motion in a reference coordinate system, where the line load is coincident with a symmetry axis of the orthotropic material. Then the equation of motion is transformed into one with respect to general coordinate system with azimuthal angle by using transformation tensor. Plane wave solutions of monoclinic systems are derived for infinite media. Finally complete solutions for the plane harmonic wave are obtained by calculating the inverse of the integral transforms, in which bulk wave poles are avoided by deforming the contour of the integration to the complex plane. Numerical results for examples of orthotropic material belonging to monoclinic symmetry are demonstrated.

• 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㎛.

• The Journal of Korean Medicine
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• v.38 no.1
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• pp.56-71
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• 2017

Objectives: The purpose of this study was to review the article using an IMU(Inertial Measurement Unit) for measuring the cervical range of motion and to evaluate the feasibility of using an IMU for measuring the cervical range of motion. Method: Scopus was used to search for the articles relating to the inclusion criteria. Which is measuring the cervical range of motion using an IMU. A total of 15 articles were selected through discussion. Degree and the reliability of the cervical range of motion and the validity of the data within the articles were extracted. Results: The measurement of the cervical range of motion using an IMU were $92.25^{\circ}$ to $138.2^{\circ}$, $122.4^{\circ}$ to $154.9^{\circ}$, $73.75^{\circ}$ to $93.1^{\circ}$ on the sagittal plane, transverse plane, and coronal plane respectively. 38 of the 43 values showed good reliability. They were larger than 0.75. 5 of the 43 values showed reliability less than 0.75. They were measured by smart phone. 16 of the 21 values showed good validity. The remaining 5 were measured by smart phone. The lower reliability and validity of smart phone were related to the protocol. The IMU can measure the coupling motion and may be used in various situations. Conclusion: The IMU may become a gold standard for measuring the cervical range of motion. The IMU measured not only the cervical range of motion but also the coupling motion. Furthermore, IMU may be used in various situations. Therefore, IMU must be considered a valuable measurement device.

• 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.

• 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.