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Semi-automatic method for surface smoothing

  • Lee, Chong-Sun;Lee, Chong-Won;Park, Se-Hyung
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.249-254
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    • 1987
  • This paper presents a new method for generating smooth free-form surface by local correction. B-spline surface is used for its convenience of local correction, and the direction of surface correction is fixed to the average-surface-normal direction. The surface to be corrected is approximated into a uniform cubic B-spline surface. Then, the smoothness (curvature arrows, iso-parametric lines) of the approximated surface is displayed with B-spline control points. When a control point near the region that needs correction is selected, a new point 1 mm higher than the original control point in the direction of the average surface normal is displayed. And the surface is corrected by giving the amount of control point movement interactively. Since the direction of correction is given by the program and the amount of correction is selected by the user, the method is called semiautomatic. sufficiently smooth surface can be obtained by this method. Examples are given to illustrate the method.

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The Charateristics of Flash-over Voltage by Humidity Variation for 22.9 kV Live Part (22.9 kV 노출충전부의 습도변화에 따른 섬락전압 변동 특성)

  • Han, Ki-Boong;Lee, Dae-Jong;Han, Woon-Ki
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1856-1858
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    • 2002
  • As the statistical data, the most of electrical shock accidents have been caused by human errors including those of mistake, carelessness, and so on during normal condition. But, there are currently no international standards for the determination of withstand distance to ensure safety of personnel form 22.9 kV electrical power facilities during their normal operation. Therefore, this paper describes the characteristics of flash-over voltage by moisture variation to establish the distance clearances in terms of electrical safety.

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Efficient Circular Object Pose Determination

  • Kim, Sungbok;Kim, Byungho
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.276-276
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    • 2000
  • This paper presents the efficient algorithms for the pose determination of a circular object with and without a priori knowledge of the object radius. The developed algorithms valid for a circular object are the result of the elaboration of Ma's work [2], which determines the pose of a conic object from two perspective views. First, the geometric constraint of a circular object and its projection on the image plane of a camera is described. The number of perspective views required for the object pose determination with and without a priori knowledge of the object radius is also discussed. Second, with a priori knowledge of the object radius, the pose of a circular object is determined from a single perspective view. The object pose information, expressed by two surface normal vectors and one position vector, is given in a closed form and with no ambiguity. Third, without a priori knowledge of the object radius, the pose of a circular object is determined from two perspective views. While the surface normal vectors are obtained from the first view, the position vector is obtained from the two views.

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Study of Behaviors of Teachers' Evaluation Based on Algebra Classrooms

  • Ye, Lijun;Yu, Ping
    • Research in Mathematical Education
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    • v.16 no.4
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    • pp.207-216
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    • 2012
  • Through quantitative video analysis of four algebra classes and statistical analysis of various types of teacher evaluation behavior in the classroom teaching, we get: (1) Teacher evaluation behavior in classroom is close to take 1/5 of the total time of the classroom teaching, and it appears most frequently in class exercises and take the longest time; (2) There are many forms of teacher evaluation behavior in classroom, and most of the behaviors are positive assessment; (3) Recognition evaluation is relatively conservative in a single form without losing fairness; (4) Classroom assessments of teachers' behaviors are primarily concerned about students' knowledge and skills mastery, and it is less involved in student feelings, attitudes and behaviors; (5) The correct teacher evaluation behavior in classroom will inspire students to create internal motivations; and (6) The correct teacher evaluation behavior in classroom can stimulate the potential of students.

Derivation of the Critical Minimum Values of the Multiple Correlation Coefficient for Augmenting Hydrologic Samples (수문자료 확충을 위한 다중상관계수의 한계최소치 유도)

  • 허준행
    • Water for future
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    • v.27 no.1
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    • pp.133-140
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    • 1994
  • The augmenting hydrologic data using a correlation procedue has been used to improve the estimates of the mean and variance at the site of interest with short record when one or more nearby sites with longer records are available. The variance of the unbiased maximum likelihood estimator of ${{\sigma}_v}^2$ derived by Moran based on the multivariate normal distribution is modified into the form of Matalas and jacobs for the bivariate normal distribution to get the critical minimum values of the multiple correlation coefficient which give the improvement for estimation the variance at the site of interest. Those values are tabulated for various lengths of records and the number of sites.

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Elastic Stability of Thin-Walled Arches subjected to Uniform Bending - Linear Bending Normal Strain Distribution -

  • Ryu, Hyo-Jin;Lim, Nam-Hyoung;Lee, Chin-Ok
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.2
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    • pp.11-15
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    • 2009
  • This paper is concerned with the elastic buckling of thin-walled arches that are subjected to uniform bending. Nonlinear strain-displacement relations with the initial curvature are substituted into the second variation of the total potential energy to obtain the energy equation including initial curvature effects. The approximation for initial curvature effects that the bending normal strain distribution is linear across the cross section is applied consistently in the derivation process. The closed form solution is obtained for flexural-torsional buckling of arches under uniform bending and, it is compared with the previous theoretical results.

Robust Bayesian analysis for autoregressive models

  • Ryu, Hyunnam;Kim, Dal Ho
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.2
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    • pp.487-493
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    • 2015
  • Time series data sometimes show violation of normal assumptions. For cases where the assumption of normality is untenable, more exible models can be adopted to accommodate heavy tails. The exponential power distribution (EPD) is considered as possible candidate for errors of time series model that may show violation of normal assumption. Besides, the use of exible models for errors like EPD might be able to conduct the robust analysis. In this paper, we especially consider EPD as the exible distribution for errors of autoregressive models. Also, we represent this distribution as scale mixture of uniform and this form enables efficient Bayesian estimation via Markov chain Monte Carlo (MCMC) methods.

An efficient high-order warping theory for laminated plates

  • Deng, Zhongmin;Huang, Chuanyue
    • Structural Engineering and Mechanics
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    • v.22 no.5
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    • pp.599-611
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    • 2006
  • The theory with hierarchical warping functions had been used to analyze composite thin-walled structure, laminated beam and had good results. In the present paper, a series of hierarchical warping functions are developed to analyze the cylindrical bending problems of composite lamina. These warping functions which refine through-the-thickness variation of displacements were composed of basic and corrective functions by taking into account of anisotropic, material discontinues, and transverse shear and normal strain. Then the hierarchical finite element method was used to form a numerical algorithm. The distribution of the displacements, in-plane stresses, transverse shear stresses and transverse normal stress for composite laminate were analyzed with the present model. The results show that the present model has precise mechanical response compared with the first deformation transverse theory and the corrective order affects the accuracy of result.

Moving load response on the stresses produced in an irregular microstretch substrate

  • Kaur, Tanupreet;Sharma, Satish Kumar;Singh, Abhishek Kumar;Chaki, Mriganka Shekhar
    • Structural Engineering and Mechanics
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    • v.60 no.2
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    • pp.175-191
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    • 2016
  • The present article is aimed at an investigation of stresses produced in a microstretch elastic half-space due to a moving load. The expressions of normal stress, shear stress and tangential couple stress produced in this case have been obtained in closed form. To find the displacement fields the perturbation method is applied. Significant effect of moving load on variation of stresses developed at different depths below the surface due to the depth of substrate and frictional coefficient of the rough surface of the medium has been observed. The effects of different shapes of irregularity and depth of irregularity on normal, shear and tangential couple stresses have been discussed. Some particular cases have also been deduced from the present investigation. Finally, the analytical developments have been illustrated numerically for aluminium-epoxy-like material substrate under the action of moving load.

Termination of Antennal Receptor Cells in Subesophageal Ganglion of Cabbage Butterfly Pieris rapae (Insecta, Lepidoptera) (배추횐나비 식도하신경절에 종지하는 촉각 지각신경세포에 관하여)

  • 전무진;이봉희
    • The Korean Journal of Zoology
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    • v.35 no.2
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    • pp.194-202
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    • 1992
  • This study has been performed to investigate normal synaptic organizations in the subesophageal ganglion and terminaiion of antennal receptor cells in the ipsilateral subesophageal gan91ion of Pieris rapae. The various normal synaptic organizations in subesophageal ganglion could be differentiated into the five types. The proximal removal of a left antenna resulted in the weakly-dark, semidark and dark degenerations in the type I bostons of the ipsilateral subesophageal ganglion. Therefore, it was concluded that the axon terminals of the receptor cells projecting from the antenna into the brain form the type 1 synapses together with the dendrites in the ipsilateral subesophageal ganglion.

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