• 제목/요약/키워드: imperfections

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장애학생을 위한 대학캠퍼스 옥외매개시설의 실태에 관한 조사 분석 (The Survey Analysis on the Exterior Connection Facility Conditions of University Campuses for Handicapped Students)

  • 최장순
    • 한국농촌건축학회논문집
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    • 제14권1호
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    • pp.21-28
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    • 2012
  • Campus facilities were recently remodeled to provide the substantial learning rights of handicapped students in many campus to embody the dignity and value as man. So this study aims to identify the exterior connection facilities for handicapped students of S and D campuses. The summaries of this research are as follows. Installations of even crossing area(1.5mx1.5m) per 50m and even rest area(1.5mx1.5m) per 30m in walking or access ramp. Improving in accordance with exterior connection facility repairing master plan in S campus. Bringing down an angle degrees of the inclined walking or access ramp in D campus. Installation of exterior braille guide sign for blind students. All handicapped students must be guaranteed the same learning rights as normal men to remove obstacles as the upper mentioned imperfections in using exterior campus facilities.

Single-Pass Induction Motor Parameter Identification Method Taking Into Account Saturation and Rotor Parameter Variations

  • McKinnon, Douglas J.;Grantham, Colin
    • Journal of international Conference on Electrical Machines and Systems
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    • 제1권2호
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    • pp.3-9
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    • 2012
  • The paper describes a novel technique for on line parameter identification of three-phase induction motors from a single, run up to speed test. Data is sampled during this test with the normal locked rotor and synchronous speed data captured on the way to reaching the motor's rated speed. Rotor parameter variations with frequency due to skin and proximity effects and other non-linear imperfections such as heating and main flux path saturation are taken into account. This method is ideal for determining and/or verifying parameters used in high performance drives.

Spline function solution for the ultimate strength of member structures

  • Zhang, Qi-Lin;Shen, Zu-Yan
    • Structural Engineering and Mechanics
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    • 제2권2호
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    • pp.185-196
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    • 1994
  • In this paper a spline function solution for the ultimate strength of steel members and member structures is derived based on total Lagrangian formulation. The displacements of members along longitudinal and transverse directions are interpolated by one-order B spline functions and three-order hybrid spline functions respectively. Equilibrium equations are established according to the principle of virtual work. All initial imperfections of members and effects of loading, unloading and reloading of material are taken into account. The influence of the instability of members on structural behavior can be included in analyses. Numerical examples show that the method of this paper can satisfactorily analyze the elasto-plastic large deflection problems of planar steel member and member structures.

Nonlinear behavior of R/C cooling tower shells

  • Hara, Takashi;Kato, Shiro;Ohya, Makoto
    • Structural Engineering and Mechanics
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    • 제5권5호
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    • pp.541-552
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    • 1997
  • In this paper the ultimate strength of the R/C cooling towers, which have initial imperfection and pre-cracked elements, is analyzed. The initial geometric imperfections arise from the unavoidable inaccuracies under the construction and the pre-cracks are assumed to be produced by the temperature stress gradients or cyclic loading under wind pressure and/or earthquake load. Both effects are strongly influenced on the strength of the R/C cooling tower shell structures. The reinforcing ratio is also the important factor to evaluate the ultimate strength of the R/C cooling tower shells. However we could not analyze these structures experimentally because of their large, analyses are the powerful schemes to evaluate the safety and reliability of these structures. The analyzed model is Port Gibson cooling tower shell. In the numerical analysis the geometric and material nonlinearities are taken into account.

Ti/Au 이중층을 이용한 초전도 상전이 센서 제작 (Fabrication of Superconducting Transition Edge Sensors based on Ti/Au Bilayer Formation)

  • 이영화;김용함
    • 한국전기전자재료학회논문지
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    • 제21권10호
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    • pp.943-949
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    • 2008
  • We report on the development of transition edge sensors for x-ray detection. The sensor technology was based on the fabrication of a superconducting film on a thin membrane. A bilayer of a superconductor, Ti, and a noble metal, Au, was e-beam evaporated on a micromachined SiNx. Another Au layer was evaporated on the two side edges of the bilayer in order not to be affected by structural imperfections at the boundaries. With the method described in the present report, the superconducting transition temperature of the device was consistently achieved to near 80 mK with a sharp transition. The energy spectrum ueasured with the device provided 37 eV FWHM for 5.9 x-rays. We also discuss the design and fabrication considerations as well as the performance of the device in detail.

Ultimate Strength Analysis of Ring-stiffened Cylinders with Initial Imperfections(I)

  • Park, Chi-Mo;Park, Dong-Min
    • International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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    • 제6권1호
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    • pp.51-59
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    • 2003
  • This paper has developed an efficient nonlinear finite element method that covers both initial deformations and initial stresses of general distribution in calculating the ultimate strength of ring-stiffened cylinders. The developed method and two widely-used commercial codes (NASTRAN and ABAQUS) were simultaneously applied to the same analysis model within the extent of those commercial codes' coverage to check the validity of the present method. After the validity check, it was used for parametric studies for more general cases of initial stress distribution, which produced some useful information about the imperfection sensitivity of the ultimate strength of ring-stiffened cylinders.

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Self Learning Fuzzy Sliding Mode Controller for Nonlinear System

  • Seo, Sam-Jun;Kim, Dong-Sik
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2002년도 ICCAS
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    • pp.103.1-103
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    • 2002
  • In variable structure control algorithms, The control law used to realized the desired sliding mode dynamics is discontinuous on the switching manifold. However, due to imperfections in switching, such as time delays, the system trajectory chatters instead of sliding along the switching manifold. This chattering is undesirable because it may excite unmodeled high frequency dynamics in the physical system. In this paper, to overcome this drawback a self-organizing fuzzy sliding mode control algorithm using gradient descent method is proposed. The proposed method has the characteristics which are viewed in conventional VSC, e.g. insensitivity to a class of disturbance, parameter variations and uncertainties ill the sliding mode. To demonstrate its performance, the proposed control algorithm is applied to an inverted pendulum system. The results show that both alleviation of chattering and performance are achieved.

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Recent applications of force/torque sensors

  • Morris, Keith A.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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    • pp.790-793
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    • 1988
  • It has become clear that through the use of force/torque sensing many previously uneconomical or unsuccessful applications can now be performed successfully. The earlier-anticipated boom of robots dominating factory production has not yet occured. Many robot installations have not met the initial expectations of users or have failed completely, souring the prospects of future robotic applications. Yet the reason many of these earlier applications have failed is very basic, that is that the robot was expected to blindly perform a task perfectly in an imperfect environment. There must be an additional level of feedback so that the robot may adapt to these imperfections, thus ensuring the ultimate success of the application. This additional level of real-world sensing is provided by force/torque sensors and their continued use will ensure the eventual proliferation of factory robots.

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비틀림 및 횡압럭을 받고 있는 복합재 원통쉘의 좌굴 (Buckling of Composite Cylindrical Shells Sugjected ot Torsion of Lateral Pressure)

  • 한병기;이성희;유택인
    • 대한기계학회논문집A
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    • 제20권5호
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    • pp.1436-1444
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    • 1996
  • The problem ofinstability of laminated circular cylindrical shell under the action of torsio or lateral pressure is investigated. The analysis is based on the Sander's theory for finite deformations of thin shell. The buckling is elastic for thin compoisite shell nad the geometry is assumed to be free of initial imperfections. The equilibrium equations are obrained by usitn the p[erturbation technique. Solution procedure is based on the Galerkin mehtod. The computer program for numerical results is made for several stacking sequence, length-to-radius ratio, and radius-to-thickness ratio. The numerical results of buckling load are present.

리니어 모터의 위치 정밀도 향상에 관한 연구 (A Study on Enhancement of the Position Accuracy of a Linear Motor)

  • 민경석;오준모;최우천
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.1828-1831
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    • 2003
  • There are various sources causing a position error in a linear motor. This paper focuses on error sources from rotational motions of a table and friction. Rotational errors occur due to imperfections during manufacturing and/or assembly of guide ways, and cause a position error at locations of interest. Friction is another factor deteriorating the position error due to its highly nonlinear behavior. The position error of the linear motor was about 20∼30$\mu\textrm{m}$. After compensating the position errors due to rotational error motions and friction. the remaining errors become about 6~8$\mu\textrm{m}$ and 2~3$\mu\textrm{m}$, respectively. It is shown that the positional accuracy of a linear can be greatly improved by compensating the two error sources.

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