• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.15-18
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• 2007

이 논문에서는 Encoder, Gyro, 다수의 IR센서를 이용한 실내용 이동로봇의 자기위치 추정에 관한 방법 중 첫 번째 실험으로 다수의 IR센서로부터 획득한 거리데이터를 이용하여 작성한 환경지도에서 모서리를 검출하고, 이를 바탕으로 각 센서에서 측정된 데이터를 병합하도록 하였다. 마지막으로 얻어진 환경지도와 실제 환경을 비교하여 그 성능을 평가하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.45-58
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• 1997

본 논문에서는 중요한 정보의 형태 중 하나인 영상 정보를 빠르고 정확하게 송수신하기 위하여 사용되는 영상 압축 방법 중 간단하면서도 좋은 성능을 가진 기존의 Block Truncation Coding(BTC)을 기반으로 하여 더욱 발전된 성능의 BTC를 구현하기 위한 방법을 제안한다. 인간의 시각적인 특성을 이용하여 각 블록을 명암에 따라 판단하여 차별된 양자화기를 사용함으로써 높은 압축에도 시각적인 측면뿐만 아니라 수치적인 측면에서 더욱 개선된 영상을 얻을 수 있었다. 또한, 모서리 부분의 특성이 잘 보존되도록 한 블록 안의 평균과 로그평균의 차를 이용하여 블록 안의 임계값을 결정하는 새로운 형태의 적응성 BTC 구현을 제안하여 BTC의 상반된 두 가지 특성인 압축률과 오차율을 개선시켰다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.547-549
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• 2001

본 논문에서는 MC의 알고리즘을 이용하여 등가면 추출시간을 단축할 수 있는 방법을 제안한다. 각 복셀 꼭지점의 밀도값을 비교하여 등가면이 형성될 수 있는 셀을 선택한다. 등가면이 형성되지 않는 빈 셀은 알고리즘을 진행하지 않고, 선택된 셀에 대해서만 등가면을 형성하기 위한 연산을 수행한다. 이때, 등가면 형성을 위한 꼭지점은 해당 모서리상에서 중앙점 보간으로 찾는다. 이러한 방법으로 형성된 등가면의 정보를 저장하는 객인 테이블을 효과적인 탐색이 가능하도록 개선함으로써 기존의 연구되다 빠르게 등가면을 추출하고 형성할 수 있다.

• Journal of the Microelectronics and Packaging Society
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• v.4 no.2
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• pp.17-24
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• 1997

Spacer가 없는 Field Emission Display 정보표시소자의 진공 패키징시 패널 유리 두 께에 따른 패널 유리가 받는 응력과 패널의 중앙 부위에서의 변위를 계산하였다. 판의 각 모서리가 고정된 상태에서 일정한 압력을 받는 경우의 bending moment로부터 우리가 받는 압력을 계산하였으며 3.7"와 5.7"크기의 두가지 경우를 실험하여 계산값과 파괴양상 및 중앙 에서의 변위를 비교하였다.변위를 비교하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.148-155
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• 1998

A trapexoidal cup of corner angles, 72。 and 102。 has been drawn to 45mm in depth. Strains on the corner flange with an acute corner angle have been compared with those on the corner flange of a square cup and those on the corner flange with an obtuse corner angle respectively. The result has shown that the strains of an acute corner angle have been relieved more than those of a square cup in case of the same conditions except of the corner angles.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.397-400
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• 2010

The interfacial hydrodynamic issues in the screen printing are experimentally investigated by using model inks that are prepared by dispersing alumina nanoparticles in water. The printing patterns of the inks that are passed through differing geometrical shapes of screen on solid surfaces with differing wettability are not solely determined by the pattern on the screen. The dynamic contact angle cannot solely explain the physics of the problem, either. The difference between the screen and printing patterns was not the same for concave and convex corners. Especially the elasticity of ink affects the edge shape.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.23-31
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• 1989

The electromagnetic diffraction problem for the incidence of E-polarized planewave on both interfaces of an arbitrary-angled dielectrc wedge is solved in conjunction with the edge condition near the tip of dielectric wedge in the static limit. The diffraction coefficients obtained by the tip of the wedge, the diffraction coefficients presented in this paper approach more closely to the exact pattem of a perfectly conducting wedge as the relative dielectric constants of the dielectric wedge increase.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.589-596
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• 2015

The occurrence of an inclined edge crack in transversely piezoelectric material is analyzed. Concentrated antiplane mechanical and inplane electrical loads are applied at the boundary and crack surface, respectively. The crack surfaces are assumed to be impermeable to the electric field. Using the Mellin transform with the introduction of a generalized displacement vector, the problem is formulated, and the Wiener-Hopf equation is derived. By solving the equation, the solution is obtained in a closed form. The intensity factors of the stress, the electric displacement, and the energy release rate are obtained for any crack length and inclination angle. These solutions can be used as fundamental solutions and can be superimposed to represent any arbitrary electromechanical loading.

• Journal of Powder Materials
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• v.14 no.1 s.60
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• pp.26-31
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• 2007

Manufacturing bulk nanostructured materials with least grain growth from initial powders is challenging because of the bottle neck of bottom-up methods using the conventional powder metallurgy of compaction and sintering. In this study, bottom-up type powder metallurgy processing and top-down type SPD (Severe Plastic Deformation) approaches were combined in order to achieve both real density and grain refinement of metallic powders. ECAP (Equal Channel Angular Pressing), one of the most promising processes in SPD, was used for the powder consolidation method. For understanding the ECAP process, investigating the powder density as well as internal stress, strain distribution is crucial. We investigated the consolidation and plastic deformation of the metallic powders during ECAP using the finite element simulations. Almost independent behavior of powder densification in the entry channel and shear deformation in the main deformation zone was found by the finite element method. Effects of processing parameters on densification and density distributions were investigated.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.1
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• pp.10-16
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• 1995

The E-polarized scattering problems by a perfect conductor strip grating are analyzed by the method of moments. For an E-polarization the induced surface current density is expected to blow up at the strip both edges. Then the induced surface current density on the strip is expanded in a series of multiplication of Ultraspherical ploynomials with zeroth order and functions with appropriate edge boundary condition. The numerical results for current density and reflection cofficient are compared with other functions, it is shown that numerical results better improves the convergence of the moment method soulutions with general incident angles than the existing several other functions. The sharp variation points in the magnitude of geometric-optical reflection coefficient can be moved by varying the incident angle, strip width, and strip spacing.