• Title/Summary/Keyword: single-pass

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Measurements and Evaluations of a Maglev Train Noise (자기부상열차 소음 측정 및 평가)

  • Kim, Hyun-Sil;Kim, Sang-Ryul;Kim, Bong-Ki
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.763-766
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    • 2006
  • The principal of a Maglev train is that floats on a magnetic field and is propelled by a linear induction motor. One of advantages is that it generates less noise compared to the wheel-on-rail train, because there are no wheels running along the rail. However, noises due to aero-dynamic disturbance and electrical system such as VVVF inverter and SLIM still occur. In this study, the Maglev cabin noises are measured during running and zero speed conditions. Pass-by noise measurements are performed to obtain outside noise during the operation of the train on the test tract. Data include a single microphone measurement as well as microphone array measurements. The array data are useful for sound source localization and more detailed noise reduction planning.

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The Application of the Welding Joint Tracking System (용접 이음 추적시스템의 응용)

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.2
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    • pp.92-99
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    • 2007
  • Welding fabrication invariantly involves three district sequential steps: preparation, actual process execution and post-weld inspection. One of the major problems in automating these steps and developing autonomous welding systems, is the lack of proper sensing strategies. Conventionally, machine vision is used in robotic arc welding only for the correction of pre-taught welding paths in single pass. In this paper, novel presented, developed vision processing techniques are detailed, and their application in welding fabrication is covered. The software for joint tracking system is finally proposed.

차세대 SAR 활용을 위한 이중 채널 항공기 SAR 시스템 구축 및 간섭기법 연구

  • Kim, Deok-Jin;Jeong, Jeong-Gyo;Kim, Seung-Hui
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.2
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    • pp.10-20
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    • 2014
  • 지금까지 대부분의 인공위성 또는 항공기 SAR 시스템은 하나의 위상 배열 안테나를 이용하며, 단 영상을 생성하고 판독하는데 주로 사용되었지만, 차세대 SAR 시스템은 다중 편파 관측이 가능하거나 이중 채널 또는 위상 배열 안테나의 분리 모드(split-antenna mode)를 통해 간섭기법의 적용이 가능한 시스템으로 발전이 이루어지고 있다. 이러한 측면에서 이 논문은 차세대 SAR 인공위성의 새로운 분석 기법 연구와 활용 증진을 위해, 유사한 기능을 보일 수 있는 이중 채널 항공기 SAR 시스템을 구축하고, 이로부터 단일 패스 간섭기법(single-pass interferometry)을 연구한 논문이다. 공간적으로 서로 다른 위치에 있는 두 개의 SAR 채널에서 동시에 수신된 레이다 신호를 간섭적으로 처리하여, 지형의 고도 정보를 추출하거나 이동하는 물체의 속도를 탐지할 수 있도록 알고리즘을 구현하였고, 새로운 활용 분야를 모색하고자 하였다.

Analysis and Design of Filter at AC Source of Sigle Phase PWM Converter (단상 PWM 컨버터의 전원측 필터의 해석 및 설계)

  • Kim, Hong-Sung;Lee, Seung-Yo;Kim, Han-Sung;Yu, Gwon-Jong;Song, Jin-Soo
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.447-449
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    • 1994
  • This paper deals with the static characteristics of filters at the AC source in single phase PWM converter using hysterisis current control method. The filters are needed to reduce the current harmonics. In general, there are two kinds of filters which can be used for current controlled PWM converter. One is the low pass filter, the other is the resonant filter for a frequency. This paper designs these filters by analysing the characteristics. And these filters are compared through performance index such as harmonic reduction factor and the value of components which make up filters.

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Evolution of stokes pulses of stimulated Raman scattering in a CeO$_2$-doped multimode fiber (GeO$_2$ 첨가 다중모드 광파이버에서 유도라만산란에 의한 스토크스 펄스 발생)

  • Yi, Yong-Woo;Hwang, In-Duck
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.7
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    • pp.1095-1099
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    • 2002
  • We experimentally investigate the evolution of nanosecond Stokes pulses in a single-pass Raman laser pumped by a Q-switched Nd:YAG laser at 1064 na As a Raman medium, a GeO2-doped graded-index multimode fiber ot 220 m long Is used. We demonstrate that efficient generation of several Stokes components with 1.5∼2.7 nanosecond pulsewidth is obtained by varying the input pump energy.

Controller Design and By-Pass Structure for the Two-Stage Grid-Connected Photovoltaic Power Conditioning System

  • Lee, Seong-Jun;Bae, Hyun-Su;Cho, B.H.
    • Proceedings of the KIPE Conference
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    • 2009.11a
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    • pp.206-208
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    • 2009
  • In this paper, a systematical controller design method for a twostage grid-connected photovoltaic power conditioning system is proposed. For a pre-stage boost converter to achieve the stable operation in the entire region of solar array, the digital resistive current mode controller is used. This algorithm is very simple to implement with a digital controller and there is no power stage parameter dependency in the controller design. For a post-stage single-phase full-bridge inverter, a PI controller with a feedforward compensation for the inner current control is employed. Furthermore, in case that the operating point of the solar array under varying environmental conditions is higher than the required voltage for the inverter current control, the bypass mode for the boost converter is possible for the more efficient operation. The proposed control scheme is validated through the experiment of the prototype two-stage power conditioning system hardware with a 200W solar array.

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Multi-Channel Single-Pass Connected Components Labeler (다채널 동작이 가능한 단일-스캔 연결 성분 라벨러)

  • Jeong, Jae-Won;Shin, Youn-Chul;Park, Joo-Heon;Lee, Myeong-Jin
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2013.06a
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    • pp.87-89
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    • 2013
  • 기존의 영상 라벨러는 이중 스캔 연결 성분 라벨링 방식이 주로 사용되어 왔다. 그러나, 이중 스캔 연결 성분 라벨링 방식은 별도의 라벨 병합 구간 때문에 실시간 처리와 다채널 처리가 어렵다. 최근 단일 스캔 연결 성분 라벨링 방법들이 제안되었지만, 이들 역시 스캔 횟수는 줄일 수 있으나 별도의 라벨 병합 구간을 제거하지는 못하였다. 본 논문에서는 별도의 라벨 병합 구간을 갖지 않는 단일 스캔 연결 성분 라벨러 구조를 제안한다. 제안하는 구조는 라인 스캔과 동시에 라벨 병합이 이루어지기 때문에 고속 동작하고, 예상 가능한 프레임 처리율을 가지며, 다채널 처리가 가능하다. 제안하는 라벨러 구조는 FPGA로 설계되었고 동작이 검증되었으며, 성능 실험을 통해 고속 동작과 다채널 영상 처리에 적합함을 확인하였다.

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A New Method of Phase Transformation (새로운 위상변성 방법)

  • Sang Se Oh
    • 전기의세계
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    • v.13 no.3
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    • pp.38-41
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    • 1964
  • This thesis is aimed to obtain efficiently economically any desired phases and single phase transformer without unbalance by using only a new transformer, applying the theory of rotating magnetic field. The brief construction and principle is as floow: two pieces of similar ring cores, triangular cores or polygonal cores are located on the upper and lower sides with equidistance. And the some number of similar leg cores, shaped a square-pillar or a sylinder, are arranged at equidistant of the core section. Ring windings or polyphase windings of AC machines are adopted as a winding method on the upper and lower cores. Three phase AC is applied to the primary windings on these cores so that the rotating magnetic field is induced on the cores and this magnetic fluxes pass through each of the secondary windings on the leg-cores with some difference in time.

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APPLYING LASER-ARC HYBRID WELDING TECHNOLOGY FOR LAND PIPELINES

  • Booth, G-S;Howse, D-S;Woloszyn, A-C;Howard, R-D
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.169-175
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    • 2002
  • World demand for natural gas has generated the need for many new land transmission pipelines to be installed in the next decade or so. Although mechanized gas metal arc welding is well developed, there are opportunities for cost savings by using alternative welding processes. Hybrid Nd:YAG laser - gas metal arc welding enables fibre optic delivery of the laser energy to a robotic welding head to be combined with the addition of extra energy and a consumable to produce good quality, deep penetration welds in a single pass. The present paper describes initial procedure development to optimize the laser and gas metal arc welding parameters for making joints in pipeline steel. Satisfactory joint quality was obtained and it is intended to develop the process to prototype field trials.

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A Novel High Speed Frequency Sweeping Signal Generator in X-band Based on Tunable Optoelectronic Oscillator

  • Sun, Mingming;Chen, Han;Sun, Xiaohan
    • Current Optics and Photonics
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    • v.2 no.1
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    • pp.53-58
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    • 2018
  • A novel X-band high speed frequency sweep signal generator based on a tunable optoelectronic oscillator (OEO) incorporating a frequency-swept laser is presented and the theoretical fundamentals of the design are explained. A prototype of the generator with tuning range from 8.8552 GHz to 10.3992 GHz and a fine step about 8 MHz is achieved. The generated radiofrequency signal with a single sideband (SSB) phase noise lower than -100 dBc/Hz@10KHz is experimentally demonstrated within the whole tunable range, without any narrow RF band-pass filters in the loop. And the tuning speed of the frequency sweep signal generator can reach to over 1 GHz/s benefiting from applying a novel dispersion compensation modular instead of several tens of kilometers of optical fiber delay line in the system.