• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.228-230
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• 2004

Samples of the aluminum alloy 3103 sheets were repeatedly deformed by ECAR up to twelve passes. Shear textures developed after the first passage of ECAR. However, the intensity of shear texture components decreased with increasing number of ECAR passages. Observations by TEM and EBSD revealed that the degree of misorientations within the deformed grains increased with increasing number of ECAR passes. Changes in textures and microstructures were hardly observed during recrystallization anneal. Upon subsequent annealing, the samples deformed by a large number of ECAR passes displayed a continuous grain growth. A higher deformation by ECAR resulted in a slower softening, which reflects the stability of ultra-fine grains against the grain growth.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.222-225
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• 2006

The effect of lubrication on the development of textures and Microstructure was studied by different lubricating condition during hot rolling of AA1050 aluminum alloy. Hot rolling without lubrication led to the evolution of the pronounced through-thickness texture gradients, whereas hot rolling with lubrication gave rise to the formation of uniform rolling texture in the whole thickness layer. The variation of texture and microstructure according to hot rolling condition are investigated by X-ray diffractometer (XRD) and Electron Back-Scattered Diffraction (EBSD). The experimental results were discussed base on the finite element method (FEM) simulation. FEM calculation reveals that a larger friction between roll and sheet causes the deviated strain state from a plane strain leading to the formation of shear textures in the thickness layers close to the surface.

• Transactions of Materials Processing
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• v.21 no.2
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• pp.126-130
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• 2012

Accurate optical texturing of light guide plate over the entire surface area is an important technical issue in LCD TV industry. Injection molding process has the potential to produce large light guide plates having highly efficient optical textures such as micro-prism array. This study is focused on the effect of the degree of replication of the micro texture of the 40" injection molded light guide plates on the overall optical performance of the display panel. Measured replication ratios of the micro-textures formed with three different types of injection molding process were considered in the modeling of prismatic micro segment array. Optical simulation was conducted and results were discussed.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.1-11
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• 1999

surface texture denotes set of tiny repetitive geometric features on an object surface. 3D Printing can readily create a surface of controlled macro-textures of high geometric complexity. Designing surface textures for 3D Printing, however, is difficult due to complex macro-structure of the tiny texture geometry since it needs to be compatible with the non-traditioal manufacturing method. In this paper we propose a visual simulation technique involving development of a virtual model-an intermediate geometric model-of the surface texture design prior to fabricating the physical model. Careful examination of the virtual model before the actual fabrication can help minimize unwanted design iterations. The proposed technique demonstrated visualization capability by comparing the virtual model with the physical model for several test cases.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.19-24
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• 2004

Symmetrical and asymmetrical rolling was performed in AA 1050 sheets. Asymmetrical rolling was carried out by using different roll velocities of upper and lower rolls. The effect of the reduction per rolling pass on the formation of textures and microstructures during symmetrical and asymmetrical rolling was studied. In order to intensify the shear deformation, symmetrical and asymmetrical rolling was carried out without lubrication. The strain states associated with rolling were investigated by simulations with the finite element method (FEM). A fairly homogeneous residual shear strain throughout the sheet thickness was observed after asymmetrical rolling. Symmetrical rolling with a high friction gave rise to a strong net shear strain gradient in the sheet thickness.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.352-359
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• 2003

Portland cement concrete (PCC) pavements are more durable and have superior surface friction compared to most dense-graded asphalt. However, data collected to date generally show PCC pavements to create more noise than asphaltic surfaces. Recent research has shown that some of the new concrete pavement textures are worthy of further examination. One of these, exposed aggregate surfaces, appear to provide better noise quality characteristics as well as good frictional characteristics and durability. In this paper, we considered the relationship between noise level and various textures of exposed aggregate concrete (EAC) pavement by tire impact noise measurement. As the results of that, it was suggested that optimum surface texture and manufacturing condition of EAC in order to reduce tire and pavement interaction noise. Conclusively, we would like to recommend optimum condition of EAC pavement at the respects of materials and treatment. Furthermore, Frequency spectrum as well as A-weighted noise level was also evaluated to analyze properties of noise between PCC and EAC.

• The Journal of the Acoustical Society of Korea
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• v.27 no.3E
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• pp.77-83
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• 2008

In the process of the sonar image textures produced, the orientation and scale factors are very significant. However, most of the related methods ignore the directional information and scale invariance or just pay attention to one of them. To overcome this problem, we apply Gabor wavelet to extract the features of sonar images, which combine the advantages of both the Gabor filter and traditional wavelet function. The mother wavelet is designed with constrained parameters and the optimal parameters will be selected at each orientation, with the help of bandwidth parameters based on the Fisher criterion. The Gabor wavelet can have the properties of both multi-scale and multi-orientation. Based on our experiment, this method is more appropriate than traditional wavelet or single Gabor filter as it provides the better discrimination of the textures and improves the recognition rate effectively. Meanwhile, comparing with other fusion methods, it can reduce the complexity and improve the calculation efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4556-4572
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• 2015

Dynamic texture (DT) recognition is a challenging problem in numerous applications. In this study, we propose a new algorithm for DT recognition based on group sparsity structure in conjunction with chaotic feature vector. Bag-of-words model is used to represent each video as a histogram of the chaotic feature vector, which is proposed to capture self-similarity property of the pixel intensity series. The recognition problem is then cast to a group sparsity model, which can be efficiently optimized through alternating direction method of multiplier algorithm. Experimental results show that the proposed method exhibited the best performance among several well-known DT modeling techniques.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.71-77
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• 1996

Considering that polycrystalline silicon, a structural material of the micromachining, is affected by a sacrificial oxide layer, the poly-oxide obtained by the thermal oxidation of polycrystalline silicon is newly proposed and estimated as the sacrificial oxide layer. The grain size of the polycrystalline silicon grown on the poly-oxide is larger than that of poly crystalline silicon grown on the conventional sacrificial oxide layer. As a result of XRD, increase of (111) textures and formation of additional (220) textures are observed on the polycrystaIline silicon deposited on the poly-oxide. Also, the polycrystalline silicon grown on the poly-oxide represents small and uniform stress.

• Transactions of Materials Processing
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• v.9 no.2
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• pp.193-202
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• 2000

The influence of rolling draughts on the formation of through-thickness textures in aluminum 5000X sheet was investigated by X-ray texture measurements and microstructure observations. In order to intensify the deformation inhomogeneities, cold rolling was performed without lubrication. Applying a large draught gave rise to the formation of the shear texture at the surface, whereas a normal plane strain testure formed at the surface after deformation with a small draught. The orientation density along the $\beta$-fiber orientations which developed in the center layer of the rolled specimen was also dependent on the strain gradients in a roll gap. Upon annealing, the deformed substructure of sample surfaces was transformed into a fine grained recrystallized microsturcture through extended recovery reaction. However, coarse grains developed after the discontinuous recrystallization which gave rise to the development of the Cube-texture.