• Title/Summary/Keyword: Singularities

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A Study on Underwater-Pipe Video Image Mosaicking using Digital Photogrammetry (수치사진측량을 이용한 수중 파이프 비디오 모자익 영상 제작에 관한 연구)

  • Kang, Jin-A;Kwon, Kwang-Seok;Kim, Byung-Guk;Oh, Yoon-Seuk
    • Journal of the Korean Association of Geographic Information Studies
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    • v.11 no.4
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    • pp.150-160
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    • 2008
  • The present domestic underwater and ocean facilities management depends on analysis with the naked eye. This study performs quantitative analysis to improve conventional methods, analyze spatial situation of underwater facilities. This research is divided into two steps; underwater image distortion correction and image mosaic step. First, underwater image distortion correction step is for the production of underwater target, calculates the correction parameters, and then developed the method that convert the original image point to whose distortion is corrected. Second step is for the obtaining pipe images installed in the underwater, corrects the distortion, and then transforms a coordinates of the correction pipe image. After coordinate transformation, we make the mosaic image using the singularities. As a result, when we measure the distance between pipe and underwater ground and compare with calculation value on mosaic image, it is showed that RMSE is 0.3cm.

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Influence of Stress Shape Function on Analysis of Contact Problem Using Hybrid Photoelasticity (광탄성 실험 하이브리드 법에 의한 접촉응력 해석시 응력형상함수의 영향)

  • Shin, Dong-Chul;Hawong, Jai-Sug
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.3
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    • pp.345-352
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    • 2013
  • In this research, a study on stress shape functions was conducted to analyze the contact stress problem by using a hybrid photoelasticity. Because the contact stress problem is generally solved as a half-plane problem, the relationship between two analytical stress functions, which are compositions of the Airy stress function, was similar to one of the crack problem. However, this relationship in itself could not be used to solve the contact stress problem (especially one with singular points). Therefore, to analyze the contact stress problem more correctly, stress shape functions based on the condition of two contact end points had to be considered in the form of these two analytical stress functions. The four types of stress shape functions were related to the stress singularities at the two contact end points. Among them, the primary two types used for the analysis of an O-ring were selected, and their validities were verified in this work.

Effective Fingerprint Classification using Subsumed One-Vs-All Support Vector Machines and Naive Bayes Classifiers (포섭구조 일대다 지지벡터기계와 Naive Bayes 분류기를 이용한 효과적인 지문분류)

  • Hong, Jin-Hyuk;Min, Jun-Ki;Cho, Ung-Keun;Cho, Sung-Bae
    • Journal of KIISE:Software and Applications
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    • v.33 no.10
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    • pp.886-895
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    • 2006
  • Fingerprint classification reduces the number of matches required in automated fingerprint identification systems by categorizing fingerprints into a predefined class. Support vector machines (SVMs), widely used in pattern classification, have produced a high accuracy rate when performing fingerprint classification. In order to effectively apply SVMs to multi-class fingerprint classification systems, we propose a novel method in which SVMs are generated with the one-vs-all (OVA) scheme and dynamically ordered with $na{\ddot{i}}ve$ Bayes classifiers. More specifically, it uses representative fingerprint features such as the FingerCode, singularities and pseudo ridges to train the OVA SVMs and $na{\ddot{i}}ve$ Bayes classifiers. The proposed method has been validated on the NIST-4 database and produced a classification accuracy of 90.8% for 5-class classification. Especially, it has effectively managed tie problems usually occurred in applying OVA SVMs to multi-class classification.

The Educational Meaning of Training : In the Works of Deleuze and Guattari (훈련과 교육의 재고찰)

  • Jeong, Chang Ho
    • Korean Educational Research Journal
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    • v.40 no.3
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    • pp.17-38
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    • 2019
  • Deleuze and Guattari revive the educational meaning of training. For them, "a violent training" always penetrates unconsciousness and consciousness. For example, we can float on water only by swimming. There is a complex historical exploration on the subject of training. Socrates distinguishes the training of spirit from that of the body, so he secures the independence of educational language. This heritage continues to us until today. However, Foucault argues that, since the modern era, humans have accepted an active obedience by "disciplinary training". Nowadays, the term "skill discipline" is also reduced to business language, and we should overcome this situation. Deleuze and Guattari suggest a "becoming-other" argument predicated on "pre-conscious singularities" on this point. The training of spirit evolves in relation to a body and other circumstance for them. Therefore, the traditional hierarchy between spirit and body is erased in their argument. Ironically, this argument displays "educational effectiveness" to success Socrates's heritage subverting to the modern thinking of it. In conclusion, we can now rethink the educational value of training based on this effectiveness. Kyudo training is an excellent example of education through body and spirit.

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Super-Cavitating Flow Problems about Two-Dimensional Symmetric Strut (2차원 대칭 스트럿 주위의 초월 공동 유동 문제의 해석)

  • Y.G.,Kim;C.S.,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.4
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    • pp.15-26
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    • 1990
  • This paper describes a potential-baoed panel method formulated for the analysis cf a supercavitating two-dimensional symmetri strut. The method employs normal dipoles and sources distributed on the foil and cavity surfaces to represent the potential flow around the cavitating hydrofoil. The kinematic boundary condition on the wetted portion of the foil surface is satisfied by requiring that the total potential vanish in the fictitious inner flow region of the foil, and the dynamic boundary condition on the cavity surface is satisfied by requiring that the potential vary linearly, i.e., the tangential velocity be constant. Green's theorem then results in a potential-based integral equation rather than the usual velocity-based formulation of Hess & Smith type, With the singularities distributed on the exact hydrofoil surface, the pressure distributions are predicted with improved accuracy compared to those of the linearized lifting surface theory, especially near the leading edge. The theory then predicts the cavity shape and cavitation number for an assumed cavity length. To improve the accuracy, the sources and dipoles on the cavity surface are moved to the newly computed cavity surface, where the boundary conditions are satisfied again. This iteration process is repeated until the results are converged.

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A Study on Restructuring of Learner-Centered Education Environment through Participatory Design - Focusing on the 'User-Integrated Platform Project' Case - (참여디자인을 통한 학습자중심교육환경 재구조화 방향연구 - '사용자-융합플랫폼 프로젝트' 사례를 중심으로 -)

  • Yoo, Myoung-Hee
    • Journal of the Korean Institute of Educational Facilities
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    • v.27 no.2
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    • pp.35-47
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    • 2020
  • The need for communication is emphasized in decision making, design methods and processes for the educational environment that contain new curricula and learning methods. In this study, we tried to find the direction and agenda of learner-centered environment restructuring through the 'user-integrated platform' in which various subjects related to school space environment understand each other's position and overcome the barriers and prejudices of each sector. The project was planned in a 'bottom-up process' method that uncovered the singularities of the previous stage and led the main contents of the next stage. The various subjects who participated in the project shared their own experiences and different positions regarding the school space. At the workshop, the topics of the participating teams were divided into two categories. The teams in the category of the 'school culture and space' insisted innovation of 'the school culture' as a premise for the restructuring of the 'school space', and proposed schools with different interpretations of 'authority and rules of school', 'the meaning of learning and play' and 'the main character of school. The teams in the category of the 'school borders and spaces' focused on 'communication' and proposed schools containing 'emotional care of students', 'borders between schools and villages', 'village community schools', and 'interspace and niche time'. After the workshop, we were able to derive the direction and architectural strategy of the school space restructuring by analyzing the works of the participants. Through this study, we confirmed the possibility of translating user's ideas into the professional domain through careful planning, preparation, facilitation, and analysis in Participatory Design.

Design of IoT System for 3D PRINTER Multi-Management (3D 프린터 다중 관리를 위한 IoT 시스템 설계)

  • Jang, Dae-Sung;Lee, Hyo-Seung;Oh, Jae-Chul
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.4
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    • pp.759-764
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    • 2020
  • As the paradigm of manufacturing and production is also changing in line with the fourth industrial revolution, the social demands and directions for Industry 4.0 cannot be reversed, and the scalability and universality of 3D printing technology are attracting attention. 3D printer is a technology developed for the purpose of reducing product development costs, and with the recent expiration of 3D printer technology patent, related technology has been revealed and various technologies applied are being researched and developed, and various singularities have been discovered and supplemented. Thus, to compensate for the inconvenience of the current output method, which requires direct offline adjustment of the machine in the use of 3D printers and 3D printing through direct input of modeling data, the design of the IoT system is proposed to perform real-time online output requests for multiple 3D printers, monitoring functions that can expect normal outputs, and online real-time remote management functions for multiple 3D printers.

Aerodynamic Analysis of an Arbitrary Three-Dimensional Blended Wing Body Aircraft using Panel Method (패널법을 이용한 임의의 3차원 BWB 형상 항공기에 대한 공력해석)

  • Lee, Sea-Wook;Yang, Jin-Yeol;Cho, Jin-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.11
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    • pp.1066-1072
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    • 2009
  • A panel method based on potential flow theory is developed for the steady/unsteady aerodynamic analysis of arbitrary three-dimensional Blended Wing Body aircraft. The panel method uses the piecewise constant source and doublet singularities as a solution. This potential based panel method is founded on the Dirichlet boundary condition and coupled with the time-stepping method. The present method uses the time-stepping loop to simulate the unsteady motion of the aircraft. The present method can solve the three-dimensional flow over the complex bodies with less computing time and provide various aerodynamic derivatives to secure the stability of Blended Wing Body aircraft. That will do much for practical applications such as aerodynamic designs and analysis of aircraft configurations and flight simulation.

A Study on the Fatigue Strength Evaluation for Fillet Weldment including Stress Singularity using Structural Stress with Virtual Node Method (응력 특이점을 갖는 필릿 용접구조물의 피로해석을 위한 가상절점법을 이용한 구조응력 계산 기법 고찰)

  • Ha Chung-In;Kang Sung-Won;Kim Myung-Hyun;Kim Man-Soo;Sohn Sang-Yong;Heo Joo-Ho
    • Journal of Welding and Joining
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    • v.24 no.3
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    • pp.27-33
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    • 2006
  • Structural stress approach is well known as a mesh-size insensitive fatigue assessment method by using finite element analyses. It is, however, difficult to estimate the structural stress (SS) at weld end points due to stress singularities when shell elements are used. In this study, fatigue evaluations with longitudinal load carrying box fillet weldment under out-of-plane bending load have been performed by using virtual node method (VNM) in order to avoid the problem, which is called the weld end effect. Various combinations of virtual node parameters, such as reference point and virtual node locations, are investigated for the estimation of proper structural stress values applying VNM in a systematic manner. The appropriate guidance of virtual node parameter has been offered for the fillet weldment considered in the study. The structural stress values obtained by VNM have also been validated by comparing the result with finite element model including weld bead. Moreover, the fatigue strength of the fillet weldment based on the equivalent structural stress is shown to be consistent with the master S-N curve.

Investigation of the behavior of a crack between two half-planes of functionally graded materials by using the Schmidt method

  • Zhou, Zhen-Gong;Wang, Biao;Wu, Lin-Zhi
    • Structural Engineering and Mechanics
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    • v.19 no.4
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    • pp.425-440
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    • 2005
  • In this paper, the behavior of a crack between two half-planes of functionally graded materials subjected to arbitrary tractions is resolved using a somewhat different approach, named the Schmidt method. To make the analysis tractable, it is assumed that the Poisson's ratios of the mediums are constants and the shear modulus vary exponentially with coordinate parallel to the crack. By use of the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations in which the unknown variables are the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the jumps of the displacements across the crack surfaces are expanded in a series of Jacobi polynomials. This process is quite different from those adopted in previous works. Numerical examples are provided to show the effect of the crack length and the parameters describing the functionally graded materials upon the stress intensity factor of the crack. It can be shown that the results of the present paper are the same as ones of the same problem that was solved by the singular integral equation method. As a special case, when the material properties are not continuous through the crack line, an approximate solution of the interface crack problem is also given under the assumption that the effect of the crack surface interference very near the crack tips is negligible. It is found that the stress singularities of the present interface crack solution are the same as ones of the ordinary crack in homogenous materials.