• Title/Summary/Keyword: exact methods

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A Study on the Application of Workstation Modeling (워크스테이션 모델링 활용에 관한 연구)

  • 김낙권;김현성
    • Archives of design research
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    • v.13
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    • pp.83-91
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    • 1996
  • In this paper, proposed through the development process of a VCR the process of making exact three-dimensional modeling data using the Alias-one of the popular workstation in product design development process. At first, the features of the NURBS curve which is the basic curve in the modeling of Alias system and the methods of building surface are reviewed. The methods of rendering, lighting and textures are reviewed for application of realistic image presentation after building basic surfaces. The synthetic application methode of these factors necessary for the product design modeling is presented through the development process of a VCR.

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Modal Nodal Transport Analysis

  • Johnson, R.Douglas
    • Nuclear Engineering and Technology
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    • v.3 no.3
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    • pp.121-128
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    • 1971
  • A unified modal-nodal expansion of tile angular distribution of neutron flux in one spatial dimension is considered, following the proposal of Harms. Several standard nodal and/or modal methods of analysis are shown to be specializations of this technique. The modal-nodal moment from of the mono-energetic transport equation with isotropic sources and scattering is derived and the infinite medium eigenvalue problem solved. The technique is shown to yield results which approximate the exact value of the inverse diffusion length in non-multiplying media more accurately than standard methods of equal or somewhat greater computational complexity.

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Face Contour Detection by Using B-spline Snake for Creating Human Face Caricature

  • Lee, Jang-Hee;Woo, Jae-Kun;Hoon Kang
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.399-402
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    • 2003
  • This paper deals with the making avatar like a caricature from human face image which is made by web camera. Generally, the Image made by web camera is not low quality but also, there are always various lights and backgrounds. So, It is impossible to recognize a human face's contour by some methods which only find some feature points of a image. Therefore, In this paper, we propose a new method for overcoming defeat of that methods. First, we got the area of human face roughly by color information. And then, we could find the exact human face's contour by using B-spline Snake.

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Motion Detection using Adaptive Background Image and Pixel Space (적응적 배경영상과 픽셀 간격을 이용한 움직임 검출)

  • 지정규;이창수;오해석
    • Journal of Information Technology Applications and Management
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    • v.10 no.3
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    • pp.45-54
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    • 2003
  • Security system with web camera remarkably has been developed at an Internet era. Using transmitted images from remote camera, the system can recognize current situation and take a proper action through web. Existing motion detection methods use simply difference image, background image techniques or block matching algorithm which establish initial block by set search area and find similar block. But these methods are difficult to detect exact motion because of useless noise. In this paper, the proposed method is updating changed background image as much as $N{\times}M$pixel mask as time goes on after get a difference between imput image and first background image. And checking image pixel can efficiently detect motion by computing fixed distance pixel instead of operate all pixel.

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The Back-bead Prediction Comparison of Gas Metal Arc Welding (아크 용접의 이면비드 예측 비교)

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.3
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    • pp.81-87
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    • 2007
  • It is important to investigate the relationship between weld process parameters and weld bead geometry for adaptive arc robot welding. However, it is difficult to predict an exact back-bead owing to gap in process of butt welding. In this paper, the quantitative prediction system to specify the relationship external weld conditions and weld bead geometry was developed to get suitable back-bead in butt welding which is widely applied on industrial field. Multiple regression analysis and artificial neural network were used as the research methods. And, the results of two prediction methods were compared and analyzed.

An Edge Detection Method for Gray Scale Images Based on their Fuzzy System Representation

  • Moon, Byung-Soo;Lee, Hyun-Chul;Kim, Jang-Yeol
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.12a
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    • pp.283-286
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    • 2001
  • Based on a fuzzy system representation of gray scale images, we derive an edge detection algorithm whose convolution kernel is different from the known kernels such as those of Roberts', Prewitt's or Sobel's gradient. Our fuzzy system representation is an exact representation of the bicubic spline function which represents the gray scale image approximately. Hence the fuzzy system is a continuous function and it provides a natural way to define the gradient and the Laplacian operator. We show that the gradient at grid points can be evaluated by taking the convolution of the image with a 3 3 kernel. We also show that our gradient coupled with the approximate value of the continuous function generates an edge detection method which creates edge images clearer than those by other methods. A few examples of applying our methods are included.

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회전체 진동감소를 위한 마그네틱 댐퍼 설계 및 응용

  • 이봉기;김영배
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.769-772
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    • 1995
  • Most turbo machines, which operate at high speeds, such as gas turbines, jet engines, pumps, and compressors are prone to perrturbing vibrations. The best vibration control method for rotors is to eliminate destabilizing factors. Careful balancing application of "more stable" oil-lubricated bearing, such as tilting pad bearings or use of anti-swirl devices in seals, are examplse of passive vibration control methods. the use of magnetic bearing is an active control method. An obvious advantage of active control is that it provides damping (or modifies system stiffness or other parameters) only when there is a need for that, i.e., in emergency states, while not affecting the rotor normal operational conditions. Moreover, active control methods provide exact position control through on-line control. In this study, a magnetic actuator, digital contrliier using DSP, and bipolar operational power supply/amplifiers were developed to show the effectiveness of reducing robot vibration. Also the curve fitting procedure to obtain the transfer function of frequency dependent component was developed. Results presented in this dissertation will provide a well-defined technical parameters in designing magnetic damper system.er system.

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SUPERCONVERGENCE OF FINITE ELEMENT METHODS FOR LINEAR QUASI-PARABOLIC INTEGRO-DIFFERENTIAL EQUATIONS

  • Li, Qian;Shen, Wanfang;Jian, Jinfeng
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.8 no.2
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    • pp.23-38
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    • 2004
  • We consider finite element methods applied to a class of quasi parabolic integro-differential equations in $R^d$. Global strong superconvergence, which only requires that partitions are quasi-uniform, is investigated for the error between the approximate solution and the Sobolev-Volterra projection of the exact solution. Two order superconvergence results are demonstrated in $W^{1,p}(\Omega)\;and\;L_p(\Omega)$, for $2\;{\leq}p\;<\;{\infty}$.

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3D buckling analysis of FGM sandwich plates under bi-axial compressive loads

  • Wu, Chih-Ping;Liu, Wei-Lun
    • Smart Structures and Systems
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    • v.13 no.1
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    • pp.111-135
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    • 2014
  • Based on the Reissner mixed variational theorem (RMVT), finite rectangular layer methods (FRLMs) are developed for the three-dimensional (3D) linear buckling analysis of simply-supported, fiber-reinforced composite material (FRCM) and functionally graded material (FGM) sandwich plates subjected to bi-axial compressive loads. In this work, the material properties of the FGM layers are assumed to obey the power-law distributions of the volume fractions of the constituents through the thickness, and the plate is divided into a number of finite rectangular layers, in which the trigonometric functions and Lagrange polynomials are used to interpolate the in- and out-of-plane variations of the field variables of each individual layer, respectively, and an h-refinement process is adopted to yield the convergent solutions. The accuracy and convergence of the RMVT-based FRLMs with various orders used for expansions of each field variables through the thickness are assessed by comparing their solutions with the exact 3D and accurate two-dimensional ones available in the literature.

Techniques in teaching English as a foreign language in the elementary school (초등학교 영어교육을 위한 기법에 관한 소고)

  • Cha, Ho-Soon
    • English Language & Literature Teaching
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    • no.4
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    • pp.117-130
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    • 1998
  • It is simply not true that anyone who can speak English can teach it. Language teaching is both a science and an art; its methods are based on a theoretical foundation and implemented by techniques. However, at a time like the present, when the scientific justification for our methods seems to be uncertain, we should concern ourselves less with theory and more with developing techniques that work with our students. The success of language teaching must be evaluated by the effectiveness of the techniques used. The purpose of the present study is to suggest some useful techniques that the teacher can utilize in teaching English as a foreign language in the elementary school. The techniques suggested are based on the investigation of the characteristics peculiar to children. The investigation takes into account cognitive, affective, and linguistic factors affecting specific techniques. The goal of language teaching is communication and all techniques should move toward this end. The resourceful teacher will provide techniques which exact more and more from the students and less and less from the teacher.

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