• Title/Summary/Keyword: four point method

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An Intelligent Visual Servoing Method using Vanishing Point Features

  • Lee, Joon-Soo;Suh, Il-Hong
    • Journal of Electrical Engineering and information Science
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    • v.2 no.6
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    • pp.177-182
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    • 1997
  • A visual servoing method is proposed for a robot with a camera in hand. Specifically, vanishing point features are suggested by employing a viewing model of perspective projection to calculate the relative rolling, pitching and yawing angles between the object and the camera. To compensate dynamic characteristics of the robot, desired feature trajectories for the learning of visually guided line-of-sight robot motion are obtained by measuring features by the camera in hand not in the entire workspace, but on a single linear path along which the robot moves under the control of a commercially provided function of linear motion. And then, control actions of the camera are approximately found by fuzzy-neural networks to follow such desired feature trajectories. To show the validity of proposed algorithm, some experimental results are illustrated, where a four axis SCARA robot with a B/W CCD camera is used.

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Seismic response analysis of an oil storage tank using Lagrangian fluid elements

  • Nagashima, Toshio;Tsukuda, Takenari
    • Coupled systems mechanics
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    • v.2 no.4
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    • pp.389-410
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    • 2013
  • Three-dimensional Lagrangian fluid finite element is applied to seismic response analysis of an oil storage tank with a floating roof. The fluid element utilized in the present analysis is formulated based on the displacement finite element method considering only volumetric elasticity and its element stiffness matrix is derived by using one-point integration method in order to avoid volumetric locking. The method usually adds a rotational penalty stiffness to satisfy the irrotational condition for fluid motion and modifies element mass matrices through the projected mass method to suppress spurious hourglass-mode appeared in compensation for one-point integration. In the fluid element utilized in the present paper, a small hourglass stiffness is employed. The fluid and structure domains for the objective oil storage tank are modeled by eight-node solid elements and four-node shell elements, respectively, and the transient response of the floating roof structure or the free surface are evaluated by implicit direct time integration method. The results of seismic response analyses are compared with those by other method and the validation of the present analysis using three-dimensional Lagrangian fluid finite elements is shown.

High-dimensional change point detection using MOSUM-based sparse projection (MOSUM 성근 프로젝션을 이용한 고차원 시계열의 변화점 추정)

  • Kim, Moonjung;Baek, Changryong
    • The Korean Journal of Applied Statistics
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    • v.35 no.1
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    • pp.63-75
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    • 2022
  • This paper proposes the so-called MOSUM-based sparse projection method for change points detection in high-dimensional time series. Our method is inspired by Wang and Samworth (2018), however, our method improves their method in two ways. One is to find change points all at once, so it minimizes sequential error. The other is localized so that more robust to the mean changes offsetting each other. We also propose data-driven threshold selection using block wild bootstrap. A comprehensive simulation study shows that our method performs reasonably well in finite samples. We also illustrate our method to stock prices consisting of S&P 500 index, and found four change points in recent 6 years.

Measurement of Isochromatic Fringe Distribution of a TV Glass Panel by Use of Photoelastic 4-step Phase Shifting Method (광탄성 4단계 위상이동법을 이용한 TV유리패널의 등색프린지 분포측정)

  • Baek, Tae-Hyun;Kim, Myung-Soo;Cho, Seong-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.25 no.1
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    • pp.1-8
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    • 2005
  • This paper presents the experimental results measured by photoelastic 4-step phase shifting method for the isochromatic fringe distribution in a TV glass panel. In the conventional photoelastic method, the isochromatic fringe orders are measured manually point by point. The 4-step phase shifting method uses four images obtained from a circular polariscope by rotating the analyzer to $0^{\circ},\;45^{\circ},\;90^{\circ}$, and $135^{\circ}$. In order to use the 4-step phase shifting method, the elements of a polariscope should be aligned to isoclinic direction at a point and/or along a line where isochromatic fringe distribution is measured. Experimental results obtained from the 4-step phase shifting method are compared with those measured by the Senarmont compensation method. Both results are well agreed. Then, isochromatic fringe distributions in the TV glass panel that is heat-treated before and after are compared. Maximum and minimum isochromatic fringe orders in the TV glass panel with before- and after-heat treatment are changed approximately two times.

Study on the Forming and Springback Analyses of a Precision Metal Bellows (정밀 금속 벨로우즈 성형 및 스프링백 해석)

  • 이상욱
    • Transactions of Materials Processing
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    • v.11 no.3
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    • pp.231-237
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    • 2002
  • The manufacturing of a metal bellows consists of the four main forming processes; deep-drawing, ironing, tube bulging and folding. Among these, the bulging and folding processes are critically important because the quality of metal bellows is greatly influenced by the forming conditions of these processes. In the present study, the finite element analysis technique is applied to the bulging and folding processes. The springback analysis is also called out. From the analysis results, it has been revealed that around the crown point the stress state is in one-directional tension and one-directional bending mode. Meanwhile, around the inner point of metal bellows it is in two-directional bending mode. It has also revealed that the thickness of metal bellows around the crown point is nearly uniform.

Performance comparison of application signalling protocol on B-ISDN bearer connection types (B-ISDN 베어러 연결 형태에 따른 응용 신호 프로토콜의 성능 비교)

  • 이성근;유상신;김덕진
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.5
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    • pp.44-54
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    • 1996
  • Various types of B-ISDN bearer connection can take place according to access types of endpoint equipments in call and number of connectio between endpoints. In this paper, performance of application signalling protocol on three basic facilities of B-ISDN CS-2 signalling system, such as connection of point-to-point, point-to-multipoint and multiconnection call, is evaluated and compared. For performacne evaluation, experimental model of B-ISDN application signalling protocol is implemented and respective message processing time of each process is measured. By applying message processing time to local exchange system, cal processing capacity of application signalling protocol on three basic connection types is evaluated by simulation method. In this paper, local exchange system is considered to have two ATM NNI links and four ATM UNI links.

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Analytical solutions to magneto-electro-elastic beams

  • Jiang, Aimin;Ding, Haojiang
    • Structural Engineering and Mechanics
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    • v.18 no.2
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    • pp.195-209
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    • 2004
  • By means of the two-dimensional basic equations of transversely isotropic magneto-electro-elastic media and the strict differential operator theorem, the general solution in the case of distinct eigenvalues is derived, in which all mechanical, electric and magnetic quantities are expressed in four harmonic displacement functions. Based on this general solution in the case of distinct eigenvalues, a series of problems is solved by the trial-and-error method, including magneto-electro-elastic rectangular beam under uniform tension, electric displacement and magnetic induction, pure shearing and pure bending, cantilever beam with point force, point charge or point current at free end, and cantilever beam subjected to uniformly distributed loads. Analytical solutions to various problems are obtained.

Types of Attitudes toward a Successful Life of Korean Nursing Students: A Q-Methodological Approach (한국 간호대 학생의 성공적 삶에 관한 태도 유형: Q방법론적 접근)

  • Jo, Kae-Hwa
    • Journal of Korean Academy of Nursing
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    • v.38 no.1
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    • pp.111-121
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    • 2008
  • Purpose: The purpose of this study was to analyze attitudes toward a successful life of students majoring in nursing science. Method: The Q-methodology which provides a method of analyzing the subjectivity of each items was used. The 32 selected Q-statements from each of 36 subjects were classified into a shape of normal distribution using a 9 point scale. The collected data was analyzed using a QUANL PC program. Result: Four types of successful life attitudes for research subjects in nursing science were identified. Type I is purpose achievement type, Type II is calling fullness type, Type III is balance maintenance type, and Type IV is happiness eagerness type. Conclusion: The results of the study indicate that different approaches to nursing professional education programs are recommended based on the four types of successful life attitudes.

Analysis of Sensibility Image According to Preference of Woman′s Golfwear (여성 골프웨어의 선호도에 따른 이미지 분석)

  • 구희경
    • Journal of the Korea Fashion and Costume Design Association
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    • v.3 no.2
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    • pp.87-106
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    • 2001
  • This study is to measure and evaluate the sensibility image for textile color and pattern design of woman's golfwear. Four-group colors and four patterns classified by a pracical survey on the market are presented. A questionnaire has 14 sensibility related words scaled by 7 point semantic differential method. The practical research is performed for 150 women screened by sensibility test for individual preference analysis based on the ages. Each subject is answered by a face-to-face interview method to improve survey's accuracy. For statistical results there are significant differences in treatment means of sensibility measurements according to the ages. Sensibility image for textile color and pattern design is significantly different according to individual character based on ages. In summary, this paper has proposed the sensibility image scale for textile color and pattern design of women's golfwears to satisfy individual sensibility according to ages. The results of this study can be effectively applied to develop textile color and pattern design based on human sensibility.

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A Study On the Comparison of the Geometric Invariance From A Single-View Image (단일 시각방향 영상에서의 기하 불변량의 특성 비교에 관한 연구)

  • 이영재;박영태
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.639-642
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    • 1999
  • There exist geometrically invariant relations in single-view images under a specific geometrical structure. This invariance may be utilized for 3D object recognition. Two types of invariants are compared in terms of the robustness to the variation of the feature points. Deviation of the invariant relations are measured by adding random noise to the feature point location. Zhu’s invariant requires six points on adjacent planes having two sets of four coplanar points, whereas the Kaist method requires four coplanar points and two non-coplanar points. Experimental results show that the latter method has the advantage in choosing feature points while suffering from weak robustness to the noise.

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