• Journal of Korea Multimedia Society
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• v.3 no.1
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• pp.34-40
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• 2000

'[n this paper, we propose an efficient multi-view image coding algorithm which finds the optimal texture from a restricted number of multi-view image. The X-Y plane of the normalized object space is divided into the triangular patches. The depth of each node is determined by appling a block based disparity compensation method. Thereafter the texture of each patch is extracted by appling an affine transformation based disparity compensation method to the multi-view images. We reduced the number of images needed to determine the texture compared to traditional methods which use all the multi-view image in the texture extraction. The experimental results show that the SNR of images encoded by the proposed algorithm is better than that of images encoded by the traditional method by the approximately 0.2dB for the test sets of multi -view image called dragon, santa, city and kid. Image data recovered after encoding by the proposed method show a better visual results than after using traditional method.

• The korean journal of orthodontics
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• v.46 no.6
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• pp.345-355
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• 2016

Objective: The purpose of this study was to determine whether predicting maturation of the midpalatal suture is possible by classifying its morphology on cone-beam computed tomography (CBCT) images and to investigate relationships with other developmental age indices. Methods: The morphology of the midpalatal suture was assessed by using CBCT images of 99 patients. Axial plane images of the midpalatal suture were classified into five stages according to the classification scheme. To make the assessment more accurate, the morphology and fusion of the midpalatal suture were additionally investigated on coronal cross-sectional planar images and volume-rendered images. Bone age was evaluated using the hand and wrist method (HWM) and cervical vertebrae method (CVM); dental age (Hellman's index), sex, and chronological age were also assessed. To evaluate relationships among variables, Spearman's rho rank test was performed along with crosstabs using contingency coefficients. Results: The HWM and CVM showed strong correlations with the maturation stage of the midpalatal suture, while other indices showed relatively weak correlations (p < 0.01). Through crosstabs, the HWM and CVM showed high association values with CBCT stage; the HWM demonstrated slightly higher values (p < 0.0001). Based on the HWM, the midpalatal suture was not fused until stage 6 in both sexes. Conclusions: Among developmental age indices, the HWM and CVM showed strong correlations and high associations, suggesting that they can be useful in assessing maturation of the midpalatal suture.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.42-47
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• 2017

In the distribution of digital image, the median filtering is used for a forgery. This paper proposed the algorithm of a image forensics detection for the classification of median filtering. For the solution of this grave problem, the feature vector is composed of 42-Dim. The detected quantity 32, 64 and 128 of forgery image edges, respectively, which are processed by the Hough transform, then it extracted from the start-end point coordinates of the Hough Lines. Also, the Hough Peaks of the Angle-Distance plane are extracted. Subsequently, both of the feature vectors are composed of the proposed scheme. The defined 42-Dim. feature vector is trained in SVM (Support Vector Machine) classifier for the MF classification of the forged images. The experimental results of the proposed MF detection algorithm is compared between the 10-Dim. MFR and the 686-Dim. SPAM. It confirmed that the MF forensic classification ratio of the evaluated performance is 99% above with the whole test image types: the unaltered, the average filtering ($3{\times}3$), the JPEG (QF=90 and 70)) compression, the Gaussian filtered ($3{\times}3$ and $5{\times}5$) images, respectively.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.585-591
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• 2014

The primary objective of the current work is to predict speed performance of the medium patrol boat over $F_N=0.5$ employing experimental materials based on the CFD before model tests. In other words, the predicted brake powers according to ship speeds are assessed satisfying the main engine capacity. The subject ships are selected the two different stern hull forms. The flow computation are conducted considering free surface and dynamic trim using a commercial CFD code(STAR-CCM+). The resistances of the bare-hull are obtained from CFD. Wave patterns, pressures and limiting streamlines on the hull and velocity distribution in the propeller plane for the two hull forms are compared using CFD. The effective powers of the object ships are assessed based on CFD. Resistance increase according to the attached appendages and quasi-propulsive efficiency are employed the experimental datas. Speed performance prediction method concerning high speed vessels like a medium patrol boat is developed employing CFD and experimental data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.25-37
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• 1992

A nonlinear finite element formulation which has the capability of handling very large geometrical changes is presented. The formulation is based on an updated material reference frame and hence true stress-strain test can be directly applied to properly characterize properties of materials which are subjected to very large deformation. For the large deformation, a consistent formulation based on the continuum mechanics approach is derived. The kinematics is referred to an updated material frame. Body equilibrium is also established in an updated geometry and the second Piola-Kirchhoff stress and the updated Lagrangian strain tensor are used in the formulation. Numerical examples for very large deformation of framed structures and plane solids are analyzed for verification purposes. The numerical solutions are obtained by an incremental numerical procedure. The importance of handing material properties properly is also demonstrated.

• Tunnel and Underground Space
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• v.22 no.6
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• pp.393-402
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• 2012

A behavior of ridge-cut rock slope had been monitored by installing inclinometers and regional slope movement toward rear side of cut face was detected. To delineate the governing factors of slope behavior, especially backward slip of ridge-cut slope, petrographic characteristics of rock cores obtained from four drilled boreholes had been examined. BIPS images inside boreholes had been acquired and structural characteristics of slope rock had been studied. Mechanical properties of discontinuity planes distributed in the drilled core had been measured and the shear strength of coal seam imbedded-discontinuity planes also had been obtained by performing the direct shear test. Monitoring results of slope behavior had been analyzed by comprehensibly considering both the mechanical and structural characteristics of slope rock and coal seam-imbedded discontinuity planes, and the potential governance of coal seam and clay minerals embedded in the joint plane on the regional slope behavior has been also identified.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.741-750
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• 2008

The aim of this study was to analyze the aerodynamic properties of the composite cable-stayed bridge by conducting three-dimensional wind tunnel tests. Focusing on the improved section of the bridge in the two-dimensional wind tunnel tests, the bridge's aerodynamic stability was estimated based on the angles of attack and the wind angles. The aerodynamic properties of vertical galloping, torsion galloping,and torsion flutter were also estimated based on the design wind velocity, and because much of the cable-stayed bridge was constructed using FCM, it was not sufficiently stiff during the bridge's construction. Therefore,the experience progressed by stages: from the full stage to the tow stage, and until the bridge became a single tower. Since the original plane was designed to be a steel box girder, the aerodynamic properties of the steel-box-type and composite-type girder could be compared. The results of this study can be utilized as basic data regarding the aerodynamic properties of medium-length and short composite cable-stayed bridges.

• Geotechnical Engineering
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• v.6 no.3
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• pp.65-76
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• 1990

A series of consolidated drained and untrained cubical triaxial tests were performed to investigate three dimensional strength characteristics of compressible sand. All specimens, which are formed by deposisting a fine sand loosely, were used. Failure strength in terms of effective stress analysis was greatly influenced by the variation of intermediate principal stress and so was failure criterion The adjusted effective frictional angles obtained by the stress state projected on the same octahedral plane showed almost same value, while the measured effective frictional angles showed considerable difference depending on the drainage conditions. Results of total stress analysis in undrained test turned out to fit Tresca's failure criterion well, but results of effective stress analysis turned out to fit Lade's failure criterion well.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.305-314
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• 2007

In this paper, we suggested a CPW-fed UWB antenna with uni-planar sectoral structure. The area where radiation device face ground is designed to have the shape of tapered slot based on exponential function. We modified a rectangular bow-tie dipole structure antenna and thus formed a multi-resonant mode. From this, we expanded the impedance bandwidth and made a feature satisfying VSWR of less than 2 between $3.1\sim10.6GHz$. The test result showed that the return loss less than -10 dB was met in the full-band UWB system and maximum gain of $0.9\sim3.1dB$ was made with the half-power beamwidth of $40.1\sim89.9^{\circ}$ on XY plane(Theta, $Phi=90^{\circ}$) and the full band. By using CPW-fed structure with no ground on the back of the substrate, the suggested antenna is easy to design and its miniaturization is also possible.

• Journal of the Korean Magnetics Society
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• v.6 no.5
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• pp.298-304
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• 1996

We have manufactured FMR spectrometer over wide range(2-35 GHz). In order to test FMR spectrometer, res¬onance absorption has been measured of the standard sample DPPH. The Q vaules of absorption line are 189-1096. As a result, We noticed that FMR spectrometer has been manufactured well. FMR studies of MgFez04 single crystal have been performed at S, J, K-band. The resonance lines have been observed for the each orientation of (100) plane at 300 K. The values of the magnetic anisotropy constant $K_{1}$ and the spectroscopic spli tting g valule have been calculated from the ferromagnetic resonance curve, $-2.9{\times}10^{4}erg/cm^{3}$, 2.02 at 23.89 GHz, $-2.2{\times}10^{4}erg/cm^{3}$, 1.89 at 5.3 GHz and $-2.8{\times}10^{4}erg/cm^{3}$, 2.01 at 3.6 GHz.