• Title/Summary/Keyword: polygonal model

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Feature Extraction Algorithm from Polygonal Model using Implicit Surface Fitting (음함수 곡면 맞춤을 이용한 다각형 모델로부터 특징 추출 알고리즘)

  • Kim, Soo-Kyun
    • Journal of Korea Multimedia Society
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    • v.12 no.1
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    • pp.50-57
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    • 2009
  • This paper proposes a extraction of feature lines on a polygonal model using local implicit surface fitting technique. To extract feature lines on a polygonal model, the previous technique addressed to compute the curvature and their derivatives at mesh vertices via global implicit surface fitting. It needs a user-specified precision parameter for finding an accurate projection of the mesh vertices onto an approximating implicit surface and requires high-time consumption. But we use a local implicit surface fitting technique to estimate the local differential information near a vertex by means of an approximating surface. Feature vertices are easily detected as zero-crossings, and can then be connected along the direction of principal curvature. Our method, demonstrated on several large polygonal models, produces a good fit which leads to improved visualization.

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The elastoplastic formulation of polygonal element method based on triangular finite meshes

  • Cai, Yong-Chang;Zhu, He-Hua;Guo, Sheng-Yong
    • Structural Engineering and Mechanics
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    • v.30 no.1
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    • pp.119-129
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    • 2008
  • A small strain and elastoplastic formulation of Polygonal Element Method (PEM) is developed for efficient analysis of elastoplastic solids. In this work, the polygonal elements are constructed based on traditional triangular finite meshes. The construction method of polygonal mesh can directly utilize the sophisticated triangularization algorithm and reduce the difficulty in generating polygonal elements. The Wachspress rational finite element basis function is used to construct the approximations of polygonal elements. The incremental variational form and a von Mises type model are used for non-linear elastoplastic analysis. Several small strain elastoplastic numerical examples are presented to verify the advantages and the accuracy of the numerical formulation.

A Study on a Hit Probability Model for Polygonal Target (다각형 표적의 명중확률 산정모델의 연구)

  • 황흥석
    • Journal of the military operations research society of Korea
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    • v.25 no.1
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    • pp.160-168
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    • 1999
  • This research focussed on developing a hit probability model for polygonal target to increase the survivability of weapon systems by its shape design. First, we defined the delivery errors and derived functions for these errors based on the assumption of bivariate normal distribution, and the derived functions for probability of shot hitting of various shapes of polygonal target. Also, we developed computer program for computation of the probability of hitting a general n-sided polygon and we have shown a sample run output. The model could be used to improve the survivability from design phase by designing optimal polygonal shape of weapon system.

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Pose alignment control of robot using polygonal approximated gripper images (다각 근사화된 그리퍼 영상을 이용한 로봇의 위치 정렬)

  • Park, Kwang-Ho;Kim, Nam-Seong;Kee, Seok-Ho;Kee, Chang-Doo
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.559-563
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    • 2000
  • In this paper we describe a method for aligning a robot gripper using image information. The region of gripper is represented from HSI color model that has major advantage of brightness independence. In order to extract the feature points for vision based position control, we find the corners of gripper shape using polygonal approximation method which determines the segment size and curvature of each points. We apply the vision based scheme to the task of alignment of gripper to reach the desired position by 2 RGB cameras. Experiments are carried out to exhibit the effectiveness of vision based control using feature points from polygonal approximation of gripper.

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Polygonal Model Analysis on Occupational Exposure Record of Radiation Workers by Work Field (업종별 방사선작업종사자 피폭 기록 다각형 모델 분석 연구)

  • Je-Wan Park;Ji-Young Han;Yong-Min Kim
    • Journal of the Korean Society of Radiology
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    • v.17 no.2
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    • pp.277-284
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    • 2023
  • Since the radiological risk is different depending on the working environment, protection measures and policies must be developed through analysis of the field area environment. Evaluating the characteristics of the field area that uses radiation should be conducted through comparative analysis with other industries, not just the numerical value of the field area. In this study, evaluation factors were derived from exposure records by the department to compare radiation occupational exposure records by sector. And then, we developed a polygonal model for comparative analysis and applied them to eight work fields through ten evaluation factors. Based on the occupational exposure record in 2020, a polygonal model was applied to compare and evaluate the characteristics of the radiation work area. Through this, the usefulness of the polygonal model was confirmed, and protection policy measures for the industry were proposed.

The Rolling Behavior of a Small Regular Polygonal Part on an Inclined Plane (경사면 위에서 작은 정다각형 부품의 구름 거동)

  • Han, In-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.11 s.254
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    • pp.1461-1471
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    • 2006
  • This paper presents the mathematical model for rolling behaviors of a small regular polygonal part on an inclined plane. Throughout the numerical analysis performed with the simulation program which has been experimentally validated, it is shown that the number of edges of the rolling polygonal part can be a measure for the energy dissipation rather than the coefficient of friction. The appropriate slope angle has been found to be around 20 degree for roughness-separation as well as shape-separation of polygonal parts which have small number of edges. In additions, the vibratory motion applied to the inclined plane is able to cause mixed parts to be separated more effectively according to the shape or the roughness. Finally, a couple of parts separation methods based on the analysis results are presented, and are validated through the numerical simulation.

Data Partitioning for Error Resilience and Incremental Rendering of 3D Model (삼차원 모델의 점진적인 렌더링과 오류 강인을 위한 효율적인 데이터 분할 방법 (CODAP))

  • 송문섭;안정환;김성진;한만진;호요성
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.1089-1092
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    • 1999
  • Applications using 3D models are increasing recently. Since 3D polygonal models are structured by a triangular mesh, the coding of polygonal models in strips of triangles is an efficient way of representing the data. These strips may be very long, and may take a long time to render or transmit. If the triangle strips are partitioned, it may be possible to perform more efficient data transmission in an error-prone environment and to display the 3D model progressively. In this paper, we devised the Component Based Data Partitioning (CODAP) which is based on Topological Surgery (TS). In order to support the error resilience and the progressively build-up rendering, we partition the connectivity, geometry, and properties of a 3D polygonal model. Each partitioned component is independently encoded and resynchronization between partitioned components is done.

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Accurate Stitching for Polygonal Surfaces

  • Zhu, Lifeng;Li, Shengren;Wang, Guoping
    • International Journal of CAD/CAM
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    • v.9 no.1
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    • pp.71-77
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    • 2010
  • Various applications, such as mesh composition and model repair, ask for a natural stitching for polygonal surfaces. Unlike the existing algorithms, we make full use of the information from the two feature lines to be stitched up, and present an accurate stitching method for polygonal surfaces, which minimizes the error between the feature lines. Given two directional polylines as the feature lines on polygonal surfaces, we modify the general placement method for points matching and arrive at a closed-form solution for optimal rotation and translation between the polylines. Following calculating out the stitching line, a local surface optimization method is designed and employed for postprocess in order to gain a natural blending of the stitching region.

Behavior of polygonal concrete-filled steel tubular stub columns under axial loading

  • Zhang, Tao;Ding, Fa-xing;Wang, Liping;Liu, Xue-mei;Jiang, Guo-shuai
    • Steel and Composite Structures
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    • v.28 no.5
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    • pp.573-588
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    • 2018
  • The objective of this paper is to investigate the mechanical performances of polygonal concrete-filled circular steel tubular (CFT) stub columns under axial loading through combined experimental and numerical study. A total of 32 specimens were designed to investigate the effect of the concrete strength and steel ratio on the compressive behavior of polygonal CFT stub columns. The ultimate bearing capacity, ductility and confinement effect were analyzed based on the experimental results and the failure modes were discussed in detail. Besides, ABAQUS was adopted to establish the three dimensional FE model. The composite action between the core concrete and steel tube was further discussed and clarified. It was found that the behavior of CFT stub column changes with the change of the cross-section, and the change is continuous. Finally, based on both experimental and numerical results, a unified formula was developed to estimate the ultimate bearing capacity of polygonal CFT stub columns according to the superposition principle with rational simplification. The predicted results showed satisfactory agreement with both experimental and FE results.

Local Parameterization of Polygonal Models Using Projection Level Set (투영 등위 집합을 이용한 다면체 모델의 부분 매개 변수화)

  • Lee, Yeon-Joo;Cha, Deuk-Hyun;Chang, Byung-Joon;Ihm, In-Sung
    • Journal of KIISE:Computer Systems and Theory
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    • v.34 no.12
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    • pp.641-655
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    • 2007
  • Parameterization has been one of very important research subjects in several application areas including computer graphics. In the parameterization research, the problem of mapping 3D polygonal model to 2D plane has been studied frequently, but the previous methods often fail to handle complicated shapes of polygonal surfaces effectively as well as entail distortion between the 3D and 2D spaces. Several attempts have been made especially to reduce such distortion, but they often suffer from the problem when an arbitrary rectangular surface region on 3D model is locally parameterized. In this paper, we propose a new local parameterization scheme based on the projection level set method. This technique generates a series of equi-distanced curves on the surface region of interest, which are then used to generate effective local parameterization information. In this paper, we explain the new technique in detail and show its effectiveness by demonstrating experimental results.