• Steel and Composite Structures
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• v.37 no.6
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• pp.663-678
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• 2020

This paper proposes a novel topology optimization method generating multiple materials for external linear plane crack structures based on the combination of IsoGeometric Analysis (IGA) and eXtended Finite Element Method (X-FEM). A so-called eXtended IsoGeometric Analysis (X-IGA) is derived for a mechanical description of a strong discontinuity state's continuous boundaries through the inherited special properties of X-FEM. In X-IGA, control points and patches play the same role with nodes and sub-domains in the finite element method. While being similar to X-FEM, enrichment functions are added to finite element approximation without any mesh generation. The geometry of structures based on basic functions of Non-Uniform Rational B-Splines (NURBS) provides accurate and reliable results. Moreover, the basis function to define the geometry becomes a systematic p-refinement to control the field approximation order without altering the geometry or its parameterization. The accuracy of analytical solutions of X-IGA for the crack problem, which is superior to a conventional X-FEM, guarantees the reliability of the optimal multi-material retrofitting against external cracks through using topology optimization. Topology optimization is applied to the minimal compliance design of two-dimensional plane linear cracked structures retrofitted by multiple distinct materials to prevent the propagation of the present crack pattern. The alternating active-phase algorithm with optimality criteria-based algorithms is employed to update design variables of element densities. Numerical results under different lengths, positions, and angles of given cracks verify the proposed method's efficiency and feasibility in using X-IGA compared to a conventional X-FEM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1652-1659
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• 2004

In this paper, we propose the algorithm that automatically measures the height of the object to move on the base plane by using the geometric information. To extract a moving object from real-time images creates the background image and each pixel is modeled by the three values. The extracted region is represented by cardboard model and calculates the coordinate center in the each part. The top and bottom point of an object are extracted by the calculated coordinate center and an iterative computation. The two points, top and bottom, are used for measuring the height. Given the vanishing line of the ground plane, the vertical vanishing point, and at least one reference height in the scene; then the height of any point from the ground may be computed by specifying the image of the point and the image of the vertical intersection with the ground plane at that point. Through a confidence valuation of the height to be measured, we confirmed similar actual height and result in the simulation experiment.

• Journal of the Korea Fashion and Costume Design Association
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• v.25 no.2
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• pp.97-110
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• 2023

The purpose of this study is to develop 3D pattern textile design of traditional Jogakbo motifs and fashion products using it. As a research method, first, through literature review, the three-dimensional representation of geometry on a plane with Jogakbo, design cases were examined. Second, through a survey, the purchase perception and design preference of Jogakbo cultural products was analyzed. Third, based on the results of the survey on color and print, the 3D pattern design for each type of Jogakbo is printed, and then textile fashion cultural products were developed. The results of this study are as follows. First, the reason why the public was not attracted to the purchase of cultural products was disatisfaction with practicality, unsuitable preference, price adequacy, aesthetics, and originality. Therefore, it was analyzed that quality, practicality, price, carry-on storage harmony and manageability, as well as aesthetic design were important factors for consumers. Second, the stereoscopic space on the plane expanded the two-dimensional plane space by forming a cube through the division and dissolution of geometry could be visualized using color expression of cubes of different brightness depending on the direction of light. Third, Jogakbo had eight types consisting of four detailed forms and three arrangement methods. The 3D pattern design could be developed through regular disolution and stereoscopic construction using Jogakbo's representative images for each type. In addition, it was found that it was easy to produce Jogakbo fashion products suitable for modern people through 3D pattern digital textile printing applying traditional colors.

• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.159-163
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• 2005

The propriety between suppliers and demanders in geometric design is very important. Although the final purpose of constructing roads is to concern about the driver s comfort, unfortunately, it has not been considered so far. We've considered the regularity and quickness in considering driver's comfort but there should be considered the safety for the accident as well. If drivers are appeared to be more speeding than designer's intention, there will be needed some supplements to increase the safety rate for the roads. Even if both an upward and downward section are supposed to exist at the same time for solid geometry of the roads like this, it is true that the recent design for the 3-D solid geometry section has been done as flat 2-D and the minimum plane curve radius and the maximum cant have been decided just by calculating without considering operating speed between an upward and downward section at the same point. In this investigation, thus, I'd like to calculate the safety of the cant by considering the speed features of the solid geometry for the first lane of four lane rural roads. To begin with, we investigated the driving speed of the car, which is not been influenced by a preceding car to analyze the influence of the geometrical structure by using Nc-97. Secondly, we statistically analyzed the driving features of the solid geometry after comparing the 6 sections, that is, measuring the driving speed feature at 12 points and combining the influence of the vertical geometry and plane geometry to the driving speed of the plane curve which was researched before. Finally, we estimated the value of cant which considers the driving speed not by using it which has applied uniformly without considering it properly, though there were some differences between a designed speed and driving speed through the result of the basic statistical analysis but by introducing the new safety rate rule, a notion of ${\alpha}$. As a result of the research, we could see the driving features of the car and suggest the safety rate which considers these. For considering the maximum cant, if we apply the safety rate, the result of this experiment, which considers 3-D solid geometry, there'll be the improvement of the driver's safety for designing roads. In addition, after collecting and analyzing the data for the road sections which have various geometrical structures by expanding this experiment it is considered that there should be developed the models which considers 3-D solid geometry.

• Journal of the Korean Geotechnical Society
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• v.30 no.5
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• pp.37-46
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• 2014

Geotechnical structures have been analyzed and constructed in various geometry conditions to maintain their stability in accordance with the characteristics of construction design. Shear strengths are generally obtained from triaxial test to apply to design analysis. Geotechnical structures under strip loading, such as earth dam, embankment, and retaining wall, have the strain in a direction, and plane strain condition. Thus, an approximate shear strengths should be applied for stability analysis suitable to ground condition. When applying shear strengths obtained from triaxial tests for slope stability analysis, the evaluation of it may underestimate the factor of safety because the implementation is not suitable for geometry condition. The paper compares shear strengths obtained from triaxial test and plane strain test based on various relative densities using weathered granite soils. Additionally, yield stress is determined by maximum axial strain 15% in triaxial test because of continuous kinematic hardening, but plane strain test can determine a failure point in critical state to evaluate the shear strengths of soils at the second plastic hardening step. This study proposes to perform an appropriate test for many geotechnical problems with plane strain condition.

• Tunnel and Underground Space
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• v.14 no.2
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• pp.142-153
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• 2004

To investigate the influence of the rock mass inhomogeneity caused by layer geometry on the regional stress distribution the cuboid models considering a homogenous rock mass, inhomogeneous rock mass with plane layers and with uneven layers were analyzed and discussed. It was confirmed that the structure and existence of layers in rock mass affected the regional stress distribution. An approach based on an inverse analysis of the measured local stresses and the 3D finite element analysis was suggested, and used to estimate the regional stress field of the homogeneous and inhomogeneous models, which consist of the surface geometry of ground and both the surface and layer geometry respectively. Additionally, the approach of the regional stress considering the layer geometry in the rock mass was verified to estimate the regional stress field for a site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3856-3863
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• 2012

A 3D reconstruction technique from stereo images that requires minimal intervention from the user has been developed. The reconstruction problem consists of three steps of estimating specific geometry groups. The first step is estimating the epipolar geometry that exists between the stereo image pairs which includes feature matching in both images. The second is estimating the affine geometry, a process to find a special plane in the projective space by means of vanishing points. The third step, which includes camera self-calibration, is obtaining a metric geometry from which a 3D model of the scene could be obtained. The major advantage of this method is that the stereo images do not need to be calibrated for reconstruction. The results of camera calibration and reconstruction have shown the possibility of obtaining a 3D model directly from features in the images.

• Journal for History of Mathematics
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• v.24 no.1
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• pp.15-29
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• 2011

This study was carrying out research on the geometry of Sulbas${\={u}}$tras as parts of looking for historical roots of oriental mathematics, The Sulbas${\={u}}$tras(rope's rules), a collection of Hindu religious documents, was written between Vedic period(BC 1500~600). The geometry of Sulbas${\={u}}$tras in ancient India was studied to construct or design for sacrificial rite and fire altars. The Sulbas${\={u}}$tras contains not only geometrical contents such as simple statement of plane figures, geometrical constructions for combination and transformation of areas, but also algebraic contents such as Pythagoras theorem and Pythagorean triples, irrational number, simultaneous indeterminate equation and so on. This paper examined the key features of the geometry of Sulbas${\={u}}$tras and the geometry of Sulbas${\={u}}$tras for the construction of the sacrificial rite and the fire altars. Also, in this study we compared geometry developments in ancient India with one of the other ancient civilizations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.236-242
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• 2019

Recently, scanning projects have been carried out in various construction and construction fields for maintenance purposes. The point cloud generated by the scan results is composed of a number of points representing the object to be scanned. The process of extracting the necessary information, including dimensions, from such scan data is called paradox. The reverse engineering process of modeling a point cloud as BIM involves considerable manual work. Owing to the time-consuming reverse engineering nature of the work, the costs increase exponentially when rework requests are made, such as design changes. Reverse engineering automation technology can help improve these problems. On the other hand, the reverse design product is variable depending on the use, and the kind and detail level of the product may be different. This paper proposes the G2BM (Geometry-to-BIM mapping) rule definition method that automatically maps a BIM object from a primitive geometry to a BIM object. G2BM proposes a process definition and a customization method for reverse engineering BIM objects that consider the use case variability.

• ETRI Journal
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• v.40 no.2
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• pp.275-282
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• 2018

Flash reduction of graphene oxide is an efficient method for producing high quality reduced graphene oxide under room temperature ambient conditions without the use of hazardous reducing agents (such as hydrazine and hydrogen iodide). The entire process is fast, low-cost, and suitable for large-scale fabrication, which makes it an attractive process for industrial manufacturing. Herein, we present a simple fabrication method for a flexible in-plane graphene micro-supercapacitor using flash light irradiation. All carbon-based, monolithic supercapacitors with in-plane geometry can be fabricated with simple flash irradiation, which occurs in only a few milliseconds. The thinness of the fabricated device makes it highly flexible and thus useful for a variety of applications, including portable and wearable electronics. The rapid flash reduction process creates a porous graphene structure with high surface area and good electrical conductivity, which ultimately results in high specific capacitance ($36.90mF\;cm^{-2}$) and good cyclic stability up to 8,000 cycles.