• International Journal of CAD/CAM
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• v.6 no.1
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• pp.59-64
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• 2006

A new method to obtain explicit re-parameterization that preserves the curve degree and parametric domain is presented in this paper. The re-parameterization brings a curve very close to the arc length parameterization under $L_2$ norm but with less segmentation. The re-parameterization functions we used are $C^1$ continuous piecewise rational linear functions, which provide more flexibility and can be easily identified by solving a quadratic equation. Based on the outstanding performance of Mobius transformation on modifying pieces with monotonic parametric speed, we first create a partition of the original curve, in which the parametric speed of each segment is of monotonic variation. The values of new parameters corresponding to the subdivision points are specified a priori as the ratio of its cumulative arc length and its total arc length. $C^1$ continuity conditions are imposed to each segment, thus, with respect to the new parameters, the objective function is linear and admits a closed-form optimization. Illustrative examples are also given to assess the performance of our new method.

• Journal of Information Technology Services
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• v.18 no.4
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• pp.151-170
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• 2019

This study conducted an empirical analysis through the Kaplan-Meier method, which is mainly used for clinical experiment analysis, on the survival rate and the survival duration of small and medium-sized enterprises using B2B e-commerce guarantee provided by credit guarantee institutions for activating B2B e-commerce transactions. The variables presented in this study are analyzed by the subdivision of the survival characteristics of enterprises using B2B e-commerce guaranteee by year, enterprises attribute, representative attribute, and guarantee use amount based on the variables tested through previous studies. According to the empirical analysis, SMEs using B2B e-commerce guarantees have a higher survival rate compared to general enterprises Simply by year and have a variety of survival characteristics, and most of the variables have a significant effect except for some variables. The implication of this study is that the researches conducted on enterprises participating in B2B e-commerce for a long period of time to support the establishment of stable business environment of SMEs and the results of empirical analysis on the survival characteristics are useful information to the stakeholders of B2B e-commerce And it can contribute to enhance the survival rate of related enterprises.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.587-595
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• 2001

Precomputation and materialization of parts. commonly called views of a data cube is a common technique in data warehouses The view is defined as the result of a query which is defined through aggregate functions In this paper we introduce the concept of fine granule view. The fine granule view is the result of a query defined through aggregate functions and the range on each dimension, where the subdivision of each dimension is based on queries access patterns. For the representation and selection of fine granule views to materialize, we define the ANO-OR cube graph and AND-OR minimum cost graph. With these structures, we propose a fine granule view materialization method. And through experiments, we evaluate the performance of the proposed method.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.157-157
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• 2017

To minimize the damage by wild birds and acquire the benefits such as protection against weeds and maintenance of water content in soil, the mulching black color vinyl after seeding should be carried out. Non-contact and non-destructive methods that can continuously determine the locations are necessary. In this study, a crop position detection method was studied that uses infrared thermal image sensor to determine the cotyledon position under vinyl mulch. The moving system for acquiring image arrays has been developed for continuously detecting crop locations under plastic mulching on the field. A sliding mechanical device was developed to move the sensor, which were arranged in the form of a linear array, perpendicular to the array using a micro-controller integrated with a stepping motor. The experiments were conducted while moving 4.00 cm/s speed of the IR sensor by the rotational speed of the stepping motor based on a digital pulse width modulation signal from the micro-controller. The acquired images were calibrated with the spatial image correlation. The collected data were processed using moving averaging on interpolation to determine the frame where the variance was the smallest in resolution units of 1.02 cm. Non-linear integral interpolation was one of method for analyzing the frequency using the normalization image and then arbitrarily increasing the limited data value of $16{\times}4pixels$ in one frame. It was a method to relatively reduce the size of overlapping pixels by arbitrarily increasing the limited data value. The splitted frames into 0.1 units instead of 1 pixel can propose more than 10 times more accurate and original method than the existing correction method. The non-integral calibration method was conducted by applying the subdivision method to the pixels to find the optimal correction resolution based on the first reversed frequency. In order to find a correct resolution, the expected location of the first crop was indicated on near pixel 4 in the inversion frequency. For the most optimized resolution, the pixel was divided by 0.4 pixel instead of one pixel to find out where the lowest frequency exists.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.3
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• pp.95-104
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• 1989

This paper presents a new shadow testing acceleration scheme for ray tracing called Hybrid Shadow Testing (HST) based on a conditional switching between the conventinal shadow testing method and Crow's shadow volume method, where the shadow polygons as well as the object polygons are registered onto the corresponding cells under the 3-D space subdivision environment. Despite the preprocessing time for the generation and registration of the shadow polygons, the total shadow testing time of the proposed algorithm, HST was approximately 50% of that of the conventional shadow testing method for several examples while the total ray tracing time was typically reduced by 30% from the conventional approach. This due to the selective use of the shadow volume method with a compromise between the maximal utilisation of shadow's spatial coherency and minimising the computational overhead for checking ray intersections with the shadow polygons. A parameter, $N_{th}$ denoting the critical number of shadow polygons between successive reflection points was used as a guideline for switching the shadow testing scheme between the conventional method and shadow volume method. A method for calculating $N_{th}$ from such statistical data as the number of object polygons, average polygon size average peripheral length of the polygons was proposed, resulting in good agreement with the experimental results.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.5
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• pp.24-32
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• 2010

In this study, we have proposed a pre-processing algorithm newly developed for improving the tracking efficiency of the optical flow method. The developed pre-processing algorithm consists of a median filter, binarization, morphology, canny edge, contour detecting and an approximation method. In order to evaluate whether the optical flow tracking capacity increases, this study applied the pre-processing algorithm to the Lucas-Kanade(LK) optical flow algorithm, and comparatively analyzed its images and tracking results with those of optical flow without the pre-processing algorithm and with the existing pre-processing algorithm(composed of median filter and histogram equalization). As a result, it was observed that the tracking performance derived from the LK optical flow algorithm with the pre-processing algorithm, shows better tracking accuracy, compared to the one without the pre-processing algorithm and the one with the existing pre-processing algorithm. It seems to have resulted by successful segmentation for characteristic areas and subdivision into inner and outer contour lines.

• Journal of the Korea Computer Graphics Society
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• v.7 no.2
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• pp.11-19
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• 2001

This paper proposes a colored paper mosaic rendering technique based on image segmentation that can automatically generate torn and tagged colored paper mosaic effect. and 3D effect that come about in human-made mosaic work can be represented by generating shadow using difference of paper thickness. Previous method did not produce satisfactory results due to the ineffectiveness of having to use pieces of the same size. The proposed two methods for determination of paper shape and location that are based on segmentation can subdivide image area by considering characteristics of image. The first method is to generate Voronoi polygon after subdividing the segmented image again using quad tree. And the second method is to apply the Voronoi diagram on each segmentation layer. Through these methods, the characteristic of the image is expressed in more detail than previous colored paper mosaic rendering method and these methods enable to produce image that is closer to human-made mosaic work.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.1
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• pp.85-94
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• 2002

In this study an adaptive node generation procedure in the Element-free Galerkin (EFG) method using bubble-meshing technique is Proposed. Since we construct the initial configuration of nodes by subdivision of background cell, abrupt changes of inter-nodal distance between higher and lower error regions are unavoidable. This unpreferable nodal spacing induces additional errors. To obtain the smooth nodal configuration the nodal configurations are regenerated by bubble-meshing technique. This bubble meshing technique was originally developed to generate a set of well-shaped triangles and tetrahedra. In odder to evaluate the effect of abrupt changes of nodal spacing, one-dimensional problems with various nodal configurations mere investigated. To demonstrate the performance of proposed scheme, the sequences of making optimal nodal configuration with bubble meshing technique are investigated for several problems.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.527-536
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• 2007

This paper proposes a 3D fashion design system that generates a 3D clothes model by using 2D patterns of clothes and drapes the 3D clothes model on a 3D human model. In the proposed system, 2D patterns of clothes are designed by selecting comer points of 2D mesh. After designing 2D patterns, a 3D clothes model is designed by describing the control points to be connected between 2D patterns. The proposed system reads a 3D human body model file and the designed 3D clothes model and creates a 3D human model putting on the clothes by using the mass-spring model based physical simulation. It calculates collision and reaction between the triangles of human body model and those of clothes for realistic simulation. Because the number of triangles is very large, the collision and reaction processing need a lot of time. To solve this problem, the proposed system decreases the number of collision and reaction processing by using the Octree space subdivision technique. It took a few seconds for generating a 3D human model putting on the designed 3D clothes.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.7_8
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• pp.408-416
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• 2003

An electronic cash system has to provide the security, to prevent the double spending and to support the divisibility of electronic cash for the easy of use. Divisible electronic cash system allows an electronic cash to be divided into subdivisions. Each subdivision is worth any desired value, but all values must add up to the original cash value. Divisible scheme brings some advantages. It reduces to make the change and also there is no necessity that a customer must withdraw a cash of the desired value whenever transactions occur. In this paper, we present an electronic cash protocol which provides the divisibility based on the double hash chain technique. Electronic cash is constructed in the form of coins. Coins, generated by the double hush chain, have different denominations. The divisibility based on the double hash chain technique. Electronic cash is constructed in the form of coins. Coins, generated by the double hash chain, have different denominations. The divisibility of an electronic cash is satisfied by the payment certificate, which is a pair of bank´s proxy signature received from the bank. When a customer pays the coin of subdivision, the fairness of that coin is certified by a customer´s signing instead of a bank. Although the proposed method does not guarantee user´s anonymity, it generates coins which cannot be forged, and the customer can use an electronic cash conveniently and efficiently with its divisibility.