• Title/Summary/Keyword: Field Study

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Time Domain Seismic Response Analysis of Nonlinear Soil-Pile-Structure Interaction System using Inverse FFT of Dynamic Fundamental Solution (동적기본해의 역FFT에 의한 비선형 지반-말뚝-구조계의 시간영역 지진응답 해석)

  • 김문겸;임윤묵;조석호;박종헌;정대희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.125-132
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    • 2002
  • In this study, a numerical method is developed for nonlinear analysis for soil-pile-structure interaction system in time domain. Finite elements considering material nonlinearity are used for the near field and boundary elements for the far field. In the near field, frame elements are used for modeling a pile and plane-strain elements for surrounding soil and superstructure. In. the far field, boundary element formulation using the dynamic fundamental solution is adopted and coupled with the near field. Transformation of stiffness matrices of boundary elements into time domain is performed by inverse FFT. Stiffness matrices in the near field and far field are coupled. Newmark direct time integration method is applied. Developed soil-pile-structure interaction analysis method is verified with available literature and commercial code. Also, parametric studies by developed numerical method are performed. And seismic response analysis is performed using actual earthquake records.

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A Study on the Current Detector with Non Contact Type (비접촉식 전류 검출 장치에 관한 연구)

  • Kim, Ki-Joon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.5
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    • pp.351-356
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    • 2018
  • Commonly, a live-line alarm can be used to measure the electric field strength of a high-voltage system to calculate its current, but it is hard to detect the electric field of shielded cables or concealed structures, such as underground distribution cables. Current sensors can detect the magnetic field in a single core wire, but they cannot determine the magnetic field about a double-core wire because the currents flow in opposite directions. Therefore, it is very difficult to detect certain current problems, such as a fault current in an extension line comprised of a double line. In this paper, to ultimately develop a sensor that can detect the current regardless of line conditions, we used a simulation to determine the concentration of the magnetic field dependent on the distribution of the external magnetic field and the path of each line's core.

A Study of Artificial Reef Subsidence in Unsteady Flow-Wave Field (비정상 흐름-파랑 공존장의 인공어초 침하특성에 관한 연구)

  • Yun, Sang Jun;Kim, Heon Tae
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.28-34
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    • 2001
  • The experimental studies for the artificial reef (AFR) subsidence characteristics in the unsteady flow field and in the unsteady flow-wave field were carried out. The difference of scou $r_sidence characteristics between in the steady flow field and in the unsteady flow field wad discussed and also the long-term subsidence characteristics in the unsteady flow field were investigated. AFR subsidence characteristics was discussed with Keulegan - Carpenter number(KC), Reynolds number (Re),. Shields number (Sn) and dimensionless time (t/Tt). And the difference of subsidence characteristics between in the unsteady flow and in the unsteady flow-wave field was discussed.ed.

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A Study of Artificial Reef Subsidence in Unsteady Flow-Wave Field (비정상 흐름-파랑 공존장의 인공어초 침하특성에 관한 연구)

  • Yun, Sang Jun;Kim, Heon Tae
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.29-29
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    • 2001
  • The experimental studies for the artificial reef (AFR) subsidence characteristics in the unsteady flow field and in the unsteady flow-wave field were carried out. The difference of scour/subsidence characteristics between in the steady flow field and in the unsteady flow field wad discussed and also the long-term subsidence characteristics in the unsteady flow field were investigated. AFR subsidence characteristics was discussed with Keulegan - Carpenter number(KC), Reynolds number (Re),. Shields number (Sn) and dimensionless time (t/Tt). And the difference of subsidence characteristics between in the unsteady flow and in the unsteady flow-wave field was discussed.

Development of Pre-training Program for Internship or Field Training for Engineering College Students (공과대학 학생들을 위한 인턴십 및 현장실습 사전교육 프로그램 개발)

  • Han, Jiyoung;Bang, Jae-hyun
    • Journal of Engineering Education Research
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    • v.18 no.4
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    • pp.3-12
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    • 2015
  • The purpose of this study was to develop a pre-training program of engineering college students for maximizing the effectiveness of internship or field training. To pursue this goal, literature review was conducted for data collection about college and corporate pre-training program for internship or field training and pre-training program(draft) was proposed. A questionnaire survey was conducted with engineering professors, students and graduates to identify the needs for pre-training program(draft) for internship or field training. Based on the results, the contents of pre-training program for internship or field training were composed of basic liberal arts, basic competency, real information related with corporation or job, and information exchange network. And key consideration for operating the pre-training program for internship or field training were proposed with the management department, regulation for the obligatory participation, meaningful organizing content, feedback of needs.

Design and embodiment of variableness band style magnetic field nerve stimulation system that apply $1^{trigger}$ $2^{mode}$ magnetic field treatment Probe for disease treatment

  • Kim, Whi-Young;Park, Sung-Joon
    • Journal of information and communication convergence engineering
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    • v.6 no.4
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    • pp.411-416
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    • 2008
  • When compose magnetic field curer by belt and band style and need by magnetic field ripple last month, produce self-discipline roof. Bred in muscle disease (lumbago, backbone disease, corpulence) back. Result that study, manufactured various variableness band style - magnetic field probe firstly. Can establish self-discipline treatment pulse price by disease secondly. Could seek correct variableness band punishment, - magnetic field probe relationship implementation and property in waist, and so on, shoulder, neck, arm, leg, ankle, wrist etc. by third. Could find variableness band style energy value that need in-magnetic field Probe's treatment by fourth. This research could design pulse of self-discipline in band form and apply each according to disease.

Study on Analysis Method for Ship's Ferromagnetic Signature using Magnetic Mock-up Model (축소 모델을 이용한 함정 자기장 신호 해석 기법 연구)

  • Yang, Chang-Seob;Chung, Hyun-Ju
    • Journal of the Korea Institute of Military Science and Technology
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    • v.10 no.4
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    • pp.38-51
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    • 2007
  • This paper describes research results for the measurement and analysis method of magnetic signatures generated from the ship's magnetic mock-up model. In this paper, we present the theoretical and experimental techniques for the separation of the permanent and the induced magnetic field from the measured magnetic signature of the mock-up model. Also, we describe the prediction method of the induced magnetic field generated from mock-up model using the Magnet s/w, one of the FEM analysis tools for the electro-magnetic field and the magnetic dipole modelling method based on the least square techniques. The proposed modelling and analysis methods can be used for the prediction and the analysis of the static magnetic field generated from the real naval ship as well as the mock-up model.

A study on the A.C. arc movement in a transverse A.C. magnetic field at atmospheric pressure (황축교류자계에 의한 대기중에서의 교류 아아크의 이동에 관한 연구)

  • 전춘생;엄기환
    • 전기의세계
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    • v.24 no.6
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    • pp.77-84
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    • 1975
  • This paper treats A.C. arc movement in a transverse A.C. magnetic field at atmospheric pressure with the purpose of selecting electrode materials and obtaining detailed data for design of A.C. air circuit breaker, plasma accelerator and plasma jet. Arc velocities in transverse magnetic field are measured by varying arc current, arc voltage, gap length, magnetic flux density and the erosion of electrode surface, which influence arc velocities. The main results are; 1)Arc velocities in transverse magnetic field have different values according to electrodes of various materials and decrease in a descending order of cold cathode, medium cathode and hot cathode. 2)Arc velocities in transverse magnetic field increases with arc current, arc voltage, gap length and magnetic flux densith and on the other hand decrease with the increase of electrode surface erosion. 3)D.C.arc velocity in D.C. magnetic field is higher than A.C. arc velocity in A.C. magnetic field of the same value.

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A Study on the Teaching Plan of Geologic Field Trip in the Earth Science Ecucation, High School (고등학교 지구 과학에서 야외 지질 조사의 지도 방법)

  • Oh, Mihn-Soo
    • Journal of The Korean Association For Science Education
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    • v.1 no.1
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    • pp.45-52
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    • 1978
  • In order to normalized the Earth Science Education, experiments and geologic field trainings are very important. But it have not carried out on account of many difficulties in current High School of Korea. These difficulties are lack of time, many problems of the text book, heavy teaching load, shortage of facilities and experimental equipments, and poor quality of teacher etc. The practical training of geologic field trip is very important in Earth Science Education. Finally, wirter propose a new teaching plan of geologic field training as follows: 1. The teacher must prepare the guide paper of field geologic training. 2. Subjects of practical training must simplify. 3. The teacher must take a pre-field investigation in order to get the teaching plan and the preparation of practical field training. 4. Let students observe for themselves on this guide, as if they were geologists. 5. The teacher must conclude about practical training after the working.

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2-D Field Analysis of Flat-type Motor (평판형 전동기의 2차원 자계 해석에 관한 연구)

  • Kim, Pill-Soo
    • Journal of IKEEE
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    • v.2 no.1 s.2
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    • pp.160-165
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    • 1998
  • This paper describes a method for field analysis inside the flat-type brushless DC motor using 2-D field simulator. Rigorous field analysis entail 3-D analysis. However, this analysis is not often appropriate for system designs because of the time and cost involved. For field analysis in this study, the 3-D problem is reduced to a 2-D boundary value problem by introducing a cylindrical cutting plane at the mean radius of the magnets. Independent of sizes and shapes of systems, the exact 2-D field results can be obtained with reasonable predictability.

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