• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1690-1704
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• 2013

An affine invariant descriptor is proposed, which is able to well represent the affine covariant regions. Estimating main orientation is still problematic in many existing method, such as SIFT (scale invariant feature transform) and SURF (speeded up robust features). Instead of aligning the estimated main orientation, in this paper ellipse orientation is directly used. According to ellipse orientation, affine covariant regions are firstly divided into 4 sub-regions with equal angles. Since affine covariant regions are divided from the ellipse orientation, the divided sub-regions are rotation invariant regardless the rotation, if any, of ellipse. Meanwhile, the affine covariant regions are normalized into a circular region. In the end, the gradients of pixels in the circular region are calculated and the partition-based descriptor is created by using the gradients. Compared with the existing descriptors including MROGH, SIFT, GLOH, PCA-SIFT and spin images, the proposed descriptor demonstrates superior performance according to extensive experiments.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3833-3839
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• 1975

The object of this experiment is to find out some flow characteristics of water through sand layer, to prevent moving sands in the filters of the fill Dam, infiltration gallery, well and Deversion Weir. This experiment was accomplished with different particle Sizes of Six Samples and different hydraulic gradient. The results obtained are Summarized as follows. 1. The critical hydraulic gradients for laminar flow was found to be between 1 and 2 when the sand used had the effective diameter, D10 of between 0.18cm and 0.45cm. 2. The critical hydraulic gradients for different particle sizes of sands were varied considerably. 3. There was a negative correlation between critical hydraulic gradient and critical Velocity, and between effective particle diameter D10 and critical hydraulic gradient respectively. 4. In spite of relatively small variation of void ratio of sands used, the values of the coefficient of permeability varied considerably. There was a negative correlation between coefficient of permeability and void ratio.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3971-3975
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• 2013

This paper introduces an Augmented Reality system recognizing hand gestures and shows results of the evaluation. The system's user can interact with artificial objects and manipulate their position and motions simply by his hand gestures. Hand gesture recognition is based on Histograms of Oriented Gradients (HOG). Salient features of human hand appearance are detected by HOG blocks. Blocks of different sizes are tested to define the most suitable configuration. To select the most informative blocks for classification multiclass AdaBoostSVM algorithm is applied. Evaluated recognition rate of the algorithm is 94.0%.

• Journal of Multimedia Information System
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• v.1 no.1
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• pp.45-53
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• 2014

This article describes a two wheelers detection system riding on people based on modified histogram of oriented gradients (HOG) for vision based intelligent vehicles. These features used correlation coefficient parameter are able to classify variable and complicated shapes of a two wheelers according to different viewpoints as well as human appearance. Also our system maintains the simplicity of evaluation of traditional formulation while being more discriminative. In this paper, we propose an evolutionary method trained part-based models to classify multiple view-based detection: frontal, rear and side view (within $60^{\circ}C$). Our experimental results show that a two wheelers riding on people detection system based on proposed approach leads to higher detection accuracy rate than traditional features.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.5
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• pp.365-375
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• 1991

Confined natural convection due to lateral temperature difference in rectangular enclosures was studied numerically and experimentally for the insulated and the constant temperature enclosures. In the case of insulated enclosure, the flow pattern and heat transfer modes are rather simple depending mainly upon Rayleigh number. In the case of isothermal enclosure, however, the phenomena of flow and heat transfer are somewhat complex and interesting due to the stable thermal gradients and various circumstances resulted from four wall temperature conditions. As a dimensionless variable, to describe properly the flow and heat transfer phenomena in the isothermal enclosure, temperature difference ratio ${\Delta}T_v/{\Delta}T_H$ is newly introduced and this parameter seems to be appropriate in the analysis of results on the effect of stabilizing thermal gradient.

• Transactions of Materials Processing
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• v.12 no.3
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• pp.244-250
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• 2003

Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed with a roll speed ratio of 1.5/l.0. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.225-227
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• 2004

Recrystallization textures of ferritic stainless steel sheets of STS 430 were varied by means of different cold rolling procedures. The conventional normal rolling led to the evolution of strong through-thickness texture gradients in the final recrystallization texture, while the cross-rolling led to a decrease in texture gradients. Micro-texture observation by EBSD revealed that the formation of band-like orientation colonies formed close to the center layer was responsible for ridging. Modification of the recrystallization texture and microstructure by cross-rolling destroyed band-like orientation colonies and consequently reduced the ridging height.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1507-1517
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• 1989

Singular values and their gradients have been used to analyze the stability and sensitivity of continuous multiloop systems. But this method has been limited to the discrete systems. This method is extended in this paper to analyze discrete systems directly in discrete domain. To do this, derived is the relationship in the disrete system between the stability margins and the minimum singular value of the return differene matrix, and also implemented is a method which computes singular value gradients. This method is applied to the lateralattitude control loop of a remotely piloted vehide both in continuous case and discrete case for verification of its utility.

• The Korean Journal of Ecology
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• v.21 no.4
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• pp.321-328
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• 1998

To describe the major environmental factors operating in coastal wetland and to characterize the distribution of the plant species over the wetland in relation to the major environmental gradients, 12 soil physical and chemical properties were determined. The gradient of water and osmotic potential of soil, electrical conductivity, sodium and chloride content and soil texture alsong the three habitat types of salt marshes, salt swamp and sand dune were occurred. The 24 coastal plant communities from principal component analysis (PCA) on the 12 variables were at designated as a gradient for soil texture and water potential related with salinity by Axis I and as a gradient for soil moisture and total nitrogen gradient by Axis II On Axis I were divided into 3 groups (1) 9 salt marsh communities including Salicornia herbacea communities (2) 5 salt swamp communities including Scirpus fluviatilis communities and (3) 10 sand dune communities including Jmperata cylindrica communities on Axis II were divided into 2 groups (1) salt marsh and sand dune communities, and (2) 3 salt swamp communities. The results could account for the zonation of plant communities on coastal wetland observed alsong envionmental gradients.

• Journal of the Korean Ceramic Society
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• v.47 no.1
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• pp.8-18
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• 2010

When metal oxides are exposed to chemical potential gradients, ions are driven to diffusive mass transport. During this transport process, the divergence of ionic fluxes offers the formation/annihilation of oxides. Therefore, the divergence of ionic flux may play an important role in the void formation in oxides. Kinetic equations were derived for describing chemical potential distribution, ionic fluxes and their divergence in oxides. The divergence was found to be the measure of void formation. Defect chemistry in scales is directly related to the sign of divergence and gives an indication of the void formation behavior. The quantitative estimation on the void formation was successfully applied to a growing magnetite scale in high temperature oxidation of iron at 823 K.