• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.73-79
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• 2023

This paper describes a level of detail (LOD) based bending spring structure and damping technique that can reliably represent strain-based dynamics (SBD) on a triangular mesh. SBD models elastic energy using strain instead of energy based on the edge length of a triangular mesh. However, when a large external force occurs, the process of calculating the elastic energy based on edges results in a degenerate triangle, which stretches in the wrong direction because it calculates an unstable strain. In this paper, we introduce an LOD-based bending spring generation and energy calculation method that can efficiently handle this problem. As a result, the technique proposed in this paper can reliably and efficiently handle SBD based on bending springs, which can provide a stable representation of cloth simulation.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.84-93
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• 2011

Levee line mapping is critical to the protection of environments in river zones, the prevention of river flood and the development of river zones. Use of the remote sensing data such as LiDAR and aerial orthoimage is efficient for river mapping due to their accessibility and higher accuracy in horizontal and vertical direction. Airborne laser scanning (LiDAR) has been used for river zone mapping due to its ability to penetrate shallow water and its high vertical accuracy. Use of image source is also efficient for extraction of features by analysis of its image source. Therefore, aerial orthoimage also have been used for river zone mapping tasks due to its image source and its higher accuracy in horizontal direction. Due to these advantages, in this paper, research on three dimensional levee line mapping is implemented using LiDAR and aerial orthoimage separately. Accuracy measurement is implemented for both extracted lines generated by each data using the ground truths and statistical comparison is implemented between two measurement results. Statistical results show that the generated 3D levee line using LiDAR data has higher accuracy than the generated 3D levee line using aerial orthoimage in horizontal direction and vertical direction.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.189-196
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• 2006

The ABS method which is modeling the shape-design helps designers concentrate upon the design intuitively, using the modeling method based on the geometrical characteristics, the property information (a point. a curve. slopes. etc.). For the multi-sided patches, the ABS Modeling attempts the modeling with the uniform domain like a right triangle and a regular square. The mentioned method can reduce the speed of modeling but it can cause the difference from a designer's intention in the process of interpolation between the attributes for object modeling. Therefore, in this paper. we propose ABS modeling based on the Chordlength domain method to minimize such differences. The Chordlength, one of the methods generating irregular domain. is the technique transforming the domain in accordance with the length and form of attributes which a shape consists of. The Chordlength domain method is performed using MEL.

• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.4-19
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• 2014

In Joseon dynasty, Gongsin-Gyoseo(Royal Edicts rewarding meritorious vassals) was issued for the reward of the contribution to the specific event of the nation. The family decided as vassals succeeded this Gongsin-Gyoseo as the family treasure to later generations. When one happened to lose this caused by an unavoidable situation such as war in this process, there were a few cases of reissuing of Gongsin-gyoseo by the nation. The confirmative reissued Gongsin-gyoseo among Gongsin-gyoseo that descended down by now are three pieces which is Park dongnyang Hoseong Gongsin-Gyoseo, Gu goeng Jeongsa Gongsin-Gyoseo, and Park jung Jeongsa Gongsin-Gyoseo. This research considered the form and mounting about these three pieces. It was indicated that the reissued Gongsin-Gyoseo was produced following the same form with the original Gongsin-Gyoseo, that is pyeongchul(moving to next lines) and daedu (writing one or two letters ahead compared to the first letter) and so on. But, it was indicated that the change of the position of the vassals in the reissued time was reflected compared to position of the original Gongsin-Gyoseo. In case of Jeonsa Gongsin-Gyoseo, it was indicated that it was 'Wonjongdaewang-whi' since the original Gongsin-Gyoseo was 'Jeongwongun-bu' and the reissued time he became the father of King Injo. Also, it was confirmed that the case of deprivation because of conspiracy such as 'Kim jajeom, Kim ryeon, Sim kiwon, Sim kisung' was produced as the original document and deleted with black ink stick. It was newly confirmed while the original Gongsin-Gyoseo was produced by a designated writer from the nation, the reissuance was written by a writer from the family of the vassals. Since the mounting of Gongsin-Gyoseo could be changed according to the favor and technique of the craftsman participated in the practical production such as Baezeopjang and economical situation of the country supplying the material, the mounting of these three Gongsin-Gyoseo should be different from the original mounting, especially because of the loss of the original by the Manchu war of 1636. The comparison result of Gongsin-Gyoseo produced in the same period with the original issued one in the record of the related Uigwe (a collection of documents from the Joseon Dynasty), the reissued one seems to be larger in the form or ratio of the mounting compared to the first issued one. First of all, the width of Byunah was expanded as twice bigger, center and both side Hoejang also was bigger as over 2cm, and the below Hoejang was expanded as 10cm, and the ratio of the upper Hoejang and the below Hoejang was wider as 1.5 times and the reissuance was 1:1 ratio. The bisect of upper shaft in Park dongnyang Hoseong Gongsin-Gyoseo is assumed as the form of an equilateral triangle, not a half-moon shape of the present, and Gu goeng and Park jung Jeongsa Gongsin-Gyoseo will be the form whose bisection form is same but the size is smaller. Chuksu is confirmed that the size is not changed significantly. Osaekdahoe can be assumed that the width was smaller compared to the first issued one. The 3 pieces of the reissued versions provide the clue of the verification for the form of the mounting of Bosa Gongsin-Gyoseo in the same production period. In the situation that the mounting of the production time was not confirmed among the currently descended Bosa Gongsin-Gyoseo, they can be very important materials.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.4
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• pp.293-308
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• 2012

The shear behavior at the particle/surface interface such as rock joint can determine the mechanical behavior of whole structure. Therefore, a fundamental understanding of the mechanisms governing its behavior and accurately estimation of the interface strength is essential. In this paper, PFC, a numerical analysis program of discrete element method was used to investigate the effects of the surface roughness on interface strength. The surface roughness was characterized by smooth, intermediate, and rough surface, respectively. In order to investigate the effects of particle shape and crushing on particle/surface interface behavior, one ball, clump, and cluster models were created and their results were compared. The shape of particle was characterized by circle, triangle, square, and rectangle, respectively. The results showed that as the surface roughness increases, interface strength and friction angle increase and the void ratio increases. The one ball model with smooth surface shows lower interface strength and friction angle than the clump model with irregular surface. In addition, a cluster model has less interface strength and friction angle than the clump model. The failure envelope of the cluster model shows non-linear characteristic. From these findings, it is verified that the surface roughness and particle shape effect on the particle/surface interface shear behavior.