• Title/Summary/Keyword: Shape description

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A Study on the Fast Method for Polygonal Approximation of Chain-Coded Plane Curves (이차원 곡선의 고속 다각형 근사화 방법에 관한 연구)

  • 조현철;박래홍;이상욱
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.1
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    • pp.56-62
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    • 1988
  • For shape description, a fast sequential method for polygonal approximation of chaincoded plane curves which are object boundaries is proposed. The proposed method performs polygonal approximation by use of the distance error from one point to a line, and its performance is enhanced by the smoothed slopes of lines. Furthermore, accumulated distance error and variable distance error threshold are proposed in order to consider and implement the visual characteristics of the human being.

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Multi-sensor based expert system for arc welding (다중 센서 정보에 의한 아크 용접 전문가 시스템)

  • 전의식;오재웅
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.797-800
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    • 1992
  • Much experience and knowledge is needed in welding because there are many working parameters and quantitative description is difficult. Therefore, introduction of expert system based on such data base has been required. In this study, welding heat and shape of bead was controlled by fuzzy inference with the welding condition, position error and voltage and current error of robot. For this, torch trajectory of robot was generated by modeling the working data with CAD and then welding was carried out through down loading to robot. And working error was controlled by on-line communication.

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Turbine Blade Surface Modeling of Point Data Fitting (측정 데이타를 이용한 터어빈 블레이드의 곡면설계)

  • Ryu, Gap-Sang;Park, Sam-Jin
    • 한국기계연구소 소보
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    • s.19
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    • pp.163-169
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    • 1989
  • Many computer programs are being developed to aid the design of physical models. These efforts highlight the importance of computer model of three dimensional object. In this paper a CAD application program is introduced which can be implemented to modeling some part that composed with 3 types of surface form ; free form surface, fillt surface, surface of revolution, and a geometry description language which can represent a shape efficiently is preseneted.

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Carniella coreana sp. nov., a new comb-footed spider (Araneae: Theridiidae) from Korea

  • Kim, Seung Tae;Yoo, Jung Sun
    • Journal of Species Research
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    • v.7 no.3
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    • pp.248-250
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    • 2018
  • A new species of Theridiidae, Carniella coreana sp. nov., is described and illustrated from Korea. The male of this newly described species is most similar to Carniella tsurui Ono, 2007 in the general shape of its palp, but can be distinguished by the winding structure of the embolus and broad tipped and twisted embolic apophysis. The genus Carniella Thaler & Steinberger, 1988 is newly recorded to Korean spider fauna.

Odontopera aurata (Lepidoptera: Geometridae), New to Korea

  • Shin, Bora;Kim, Sung-Soo;Choi, Sei-Woong
    • Animal Systematics, Evolution and Diversity
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    • v.38 no.2
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    • pp.103-107
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    • 2022
  • One ennomine species, Odontopera aurata (Prout, 1915) was newly recorded from Korea. Odontopera aurata, a species of Ennominae, is characterized by the dark yellowish forewing that shows centrally mottled with blackish dots, weakly slanted and blackish postmedial line, and undulating termen, and the yellowish hindwing with black postmedial line and short discal dot. Odontopera aurata is externally indistinguishable from O. arida but can be distinguished by the shape of furcal arm of the male genitalia. We provide diagnosis, description of adults and male genitalia, and DNA information.

AN ANALYSIS OF THE CHIMNEY WALL

  • Yang, Young-Kyun
    • Korean Journal of Mathematics
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    • v.7 no.1
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    • pp.27-35
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    • 1999
  • As seen from the ammonium chloride experiment (Chen & Chen [1], Roberts & Loper [11], the interface near chimneys has an up-rising shape and we observe thickening of mush next to chimney. We analyze the thermal boundary layer around chimney that forms as the mush is cooled locally by the fluid rising through the chimney. We obtain solutions of the temperature, the solid fraction, and the pressure in the chimney wall. Also, our expression of the pressure shows that the fluid flow can require a huge pressure in order to pass through the chimney wall if its permeability is very small. We present a simple analytic description of the up-rising shape near the exit of the chimney, due to the fact that the comparatively solute (i.e. $NH_4Cl$ in the case of the ammonium chloride experiment)-rich fluid near the chimney tends to crystallize as it is chilled by the rising jet of cold fluid in the chimney.

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A New Species of the Genus Caminus (Astroporida: Geodiidae) from Korea

  • Shim, Eun-Jung;Sim, Chung-Ja
    • Animal Systematics, Evolution and Diversity
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    • v.28 no.3
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    • pp.208-211
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    • 2012
  • Caminus jejuensis n. sp was collected from depth of 20 m at Geomeunyeo, Seogwipo, Jejudo Island by a SCUBA diving from April 2004 to December 2008. This new species is similar to C. chinensis from China in the composition of spicules except for the spherasters and they differ in spicule size and growth form. This species has longer orthotriaenes and spherules, smaller sterrasters and oxyasters than those of C. chinensis. This species also has many spherasters in choanosome, but C. chinensis lacks. Morever, the new species is a massive shape with wrinkles, whereas C. chinensis is a club shape with smooth surface. Description and figures of the new species are provided.

Octree model based fast three-dimensional object recognition (Octree 모델에 근거한 고속 3차원 물체 인식)

  • 이영재;박영태
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.9
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    • pp.84-101
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    • 1997
  • Inferring and recognizing 3D objects form a 2D occuluded image has been an important research area of computer vision. The octree model, a hierarchical volume description of 3D objects, may be utilized to generate projected images from arbitrary viewing directions, thereby providing an efficient means of the data base for 3D object recognition. We present a fast algorithm of finding the 4 pairs of feature points to estimate the viewing direction. The method is based on matching the object contour to the reference occuluded shapes of 49 viewing directions. The initially best matched viewing direction is calibrated by searching for the 4 pairs of feature points between the input image and the image projected along the estimated viewing direction. Then the input shape is recognized by matching to the projectd shape. The computational complexity of the proposed method is shown to be O(n$^{2}$) in the worst case, and that of the simple combinatorial method is O(m$^{4}$.n$^{4}$) where m and n denote the number of feature points of the 3D model object and the 2D object respectively.

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Shock Graph for Representation and Modeling of Posture

  • Tahir, Nooritawati Md.;Hussain, Aini;Abdul Samad, Salina;Husain, Hafizah
    • ETRI Journal
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    • v.29 no.4
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    • pp.507-515
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    • 2007
  • Skeleton transform of which the medial axis transform is the most popular has been proposed as a useful shape abstraction tool for the representation and modeling of human posture. This paper explains this proposition with a description of the areas in which skeletons could serve to enable the representation of shapes. We present algorithms for two-dimensional posture modeling using the developed simplified shock graph (SSG). The efficacy of SSG extracted feature vectors as shape descriptors are also evaluated using three different classifiers, namely, decision tree, multilayer perceptron, and support vector machine. The paper concludes with a discussion of the issues involved in using shock graphs to model and classify human postures.

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A Study on Shape Determination of Cable-Net Structures with Restrained Conditions (제한조건을 갖는 케이블-네트 구조물의 형상결정에 관한 연구)

  • 이장복;권택진;하창우
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.325-332
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    • 1999
  • As part of the conceptual disign of cable and membrane structures, the adequate shape is decisive with respect to load bearing behaviour and aesthetic expression of the structure. The force densities which are the force-length ratio are very useful parameters for the description of equilibrium state of any general cable-net structures. Because equilibrium states are obtained by solving linear equations the force desity method has a advantage compared with other solution strategies. But if there are futher restrainted conditions in force density the linear method will be extended to nonlinear one. The numeriacl methods are based upon least square and general inverse method for sieving nonlinear eqations. In this paper, the results from two methods is compared through several examples.

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