• 전자공학회논문지 IE
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• v.44 no.4
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• pp.48-54
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• 2007

Due to the diverse utilization of multimedia, interests are increasing towards processing (saving, editing, searching, etc) three dimensional object data. This paper proposes and realizes a retrieval system for three dimensional objects using reflective symmetry. For the retrieval method, a reflective symmetric axis with a projector is used. The symmetric plane is calculated by the reflection symmetry, and the depth buffer is calculated for the symmetric plane. Then, by applying the Fourier Transform to the depth buffer, the feature vector for the object is generated and retrieved. For the sample of inquiry, the model of similar symmetry was extracted using the benchmark data from Konstantz University. Considering that most of the objects have symmetrical characteristics, the proposed method of retrieving three dimensional objects using a reflective symmetric surface is an outstanding retrieval system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.110-117
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• 2000

Vibration modes obtained from a modal analysis can be better explained from a screw theoretical standpoint. A vibration mode can be geometrically interpreted as a pure rotation about the vibration center in a plane and as the twisting motion on a screw in a three dimensional space. This paper, presents the method to diagonalize a spatial stiffness matrix by use of a parallel axis congruence transformation. It also describes that the stiffness matrix diagonalized by a congruence transformation, can have the planes of symmetry depending on the location of the center of elasticity. For a plane of symmetry, any vibration mode can be expressed by the axis of vibration. Analytical solutions for the axis of vibration has been derived.

• Korean Journal of Optics and Photonics
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• v.4 no.4
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• pp.390-396
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• 1993

When a one-dimensional telecentric paraxial holographic kinoform is used as a Fourier transform lens, we analyzed three surface-relief structures, i.e., plano-convex, convex-plano and biconvex shapes, employing exact raytracing method based on Snell's law. For the kinoform of E/8 and focal length of 15 mm, the number of zones, the thickness, and the slope of parabolic surfaces are varied by changing the refractive indicies of kinoform material and surrounding medium. It is found that biconvex shape gives the best results in general, although off-axis performance degrades in all cases as the slope of parabolic surfaces increases.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.19-26
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• 1991

The complete, fully-elliptic Reynolds-averaged Navier-Stokes equations have been solved using a two-layer model, in the $\kappa-\varepsilon$ turbulence model, for the axisymmetric body. Numerically generated boundary-fitted coordinate system and the finite analytic methods are used to solve the governing equations. Calculations are started after the middle body with given inlet conditions. The velocities and the turbulent quantities at the inlet section are specified by solving the boundary layer equations or by standard flat-plate boundary profiles. The effects of the inlet conditions on the solution are investigated.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.195.1-195.1
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.49-50
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• 2006

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.196-201
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• 2013

In this paper, a dual-mode balanced filter with symmetric coupled composite right/left-handed transmission line is introduced. Unlike the other symmetric structure, this configuration has the ability to operate under both common- and differential-mode excitation. These properties are achievable through providing physical short circuit by means of ground vias at the center of each unit-cell along the symmetry plane of the structure. Because the CRLH unit-cells are operated under both common- and differential-mode excitation, we implemented a balanced filter using these properties. To validity these features, a five-cell four port coupled CRLH-TL is simulated, fabricated and measured and the obtained performances agree with the simulation results under both common- and differential-mode excitation.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.453-460
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• 2010

This study was one of the caries pattern studies. The purpose was to investigate the degree of intraoral symmetry of dental caries in the primary dentition. The dmfs data from children aged 36 to 71 months were analyzed. Pearson correlation coefficients between right teeth and left teeth were from 0.558 (upper canines) to 0.847 (upper central incisors) and 0.905 in total (P<0.01). Differences between right teeth and left teeth were mostly not significant (P>0.05). Pearson correlation coefficients between upper teeth and lower teeth were from 0.150 (right lateral incisors) to 0.506 (right first molars) and 0.680 in total (P<0.01). Differences between upper teeth and lower teeth were mostly significant (P<0.05). Percentages of bilateral caries experience cases per cases having caries experience were from 34.0% (upper canines) to 80.1% (upper central incisors), and from 53.9% (distal) to 84.9% (mesial) in upper central incisors, from 34.1% (mesial) to 45.0% (occlusal) in upper first molars, from 20.7% (distal) to 48.0% (occlusal) in upper second molars, from 34.4% (buccal) to 58.1% (occlusal) in lower first molars, and from 29.7% (distal) to 61.4% (occlusal) in lower second molars, respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1255-1265
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• 1992

Under uniform heat flow, the thermal stress intensity factors for the interfacial crack on a rigid cusp-type inclusion are determined by Hilbert problem expressed with complex variable. The thermal stress intensity factors are expressed in terms of the periodic function of heat flow angle. When the tip of the interfacial crack meets that of the cusp crack, the thermal stress intensity factors have singularities. The thermal stress intensity factors at the interfacial crack tip located in the distance from the cusp crack tip vary with the location of the interfacial crack tip. From the results of the analysis, the complex potential functions and the thermal stress intensity factors for the cusp-type inclusion without the interfacial crack are derived under the cusp surface boundary conditions insulated or fixed to zero relative temperature.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.1
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• pp.63-71
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• 2011

Major type of facial asymmetry results from facial deformity and needs surgical correction. To diagnose facial asymmetry and set a treatment plane for patients, setting a sagittal reference plane is crucial. The purpose of this study is comparison of measurements of sagittal soft tissue reference point to three different sagittal planes. The subjects are 25 of asymmetry patients (M:15, F:10) and 19 of normal people. There are differences in point Gnathion and Stomion. Most of measurement of sagittal reference points showed within 1 mm difference from sagittal reference plane. Deviation of point Pronasale in Sa1 plane revealed significant difference among 3 reference planes. The deviation of Gnathion was proportional to the deviation of Stomion in all 3 reference planes.