• 제목/요약/키워드: Field measurement

검색결과 5,083건 처리시간 0.038초

Simulated Indoor Pass-by 시스템에서의 최적 Microphone Array 형태와 검증

  • 유윤선
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2009년도 추계학술대회 논문집
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    • pp.225-228
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    • 2009
  • The simulated indoor pass-by noise measurement system is the tool to measure and evaluate the pass-by noise at the test laboratory, without doing measurement at the field. This measurement system can realize the precision measurement under the specific condition and overcome the limitations of the field measurement, i.e. weather conditions, repeatability, .. This measurement system is done in time domain process using the array techniques, which synchronizes the time signals. The reliability of the obtained result depends on the array shapes, which can generate the moving source effect. In this paper, the validations are checked focusing the time domain synchronization of the signals with the optimum microphone array shape.

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마이크로 레이저 평면빔을 이용한 마이크로채널 내에서의 Micro-LIF 측정 (Micro-LIF Measurement in a Micro-channel Using an Micro Laser Light Sheet)

  • 윤상열;김재민;김수헌;김경천
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1540-1545
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    • 2004
  • Measurement of concentration fields in a micro-channel is the crucial technology in the area of Lab-on-a-chip to be used for various bio-chemical applications. It is wel-known that the only possible way to measure the concentration field in the micro-channel is using micro-LIF(Laser Induced Fluorescence) method. However, an accurate concentration field at a given cross plane in a micro-channel has not been made so far due to the limit of light illumination. The present study demonstrates a novel method to provide an ultra thin laser sheet beam having 5 microns thickness by a micro focus laser line generator. Nile Blue A was used as fluorescent dye for LIF measurement. The laser sheet beam illuminates an exact plane of concentration measurement in the micro-channel to increase the signal to noise ratio and reduce the depth uncertainty considerably.

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Measurement Allocation by Shapley Value in Wireless Sensor Networks

  • Byun, Sang-Seon
    • Journal of information and communication convergence engineering
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    • 제16권1호
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    • pp.38-42
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    • 2018
  • In this paper, we consider measurement allocation problem in a spatially correlated sensor field. Our goal is to determine the probability of each sensor's being measured based on its contribution to the estimation reliability; it is desirable that a sensor improving the estimation reliability is measured more frequently. We consider a spatial correlation model of a sensor field reflecting transmission power limit, noise in measurement and transmission channel, and channel attenuation. Then the estimation reliability is defined distortion error between event source and its estimation at sink. Motivated by the correlation nature, we model the measurement allocation problem into a cooperative game, and then quantify each sensor's contribution using Shapley value. Against the intractability in the computation of exact Shapley value, we deploy a randomized method that enables to compute the approximate Shapley value within a reasonable time. Besides, we envisage a measurement scheduling achieving the balance between network lifetime and estimation reliability.

Simultaneous Temperature and Velocity Fields Measurements near the Boiling Point

  • Doh, Deog-Hee;Hwang, Tae-Gyu;Koo, Bon-Young;Kim, Seok-Ro
    • Journal of Advanced Marine Engineering and Technology
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    • 제31권5호
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    • pp.531-542
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    • 2007
  • Simultaneous measurement technique for temperature and velocity fields near a heated solid body has been constructed. The measurement system consists of a 3-late CCD color camera, a color image grabber, a 1ighting system, a host computer and a software for the whole quantification process. Thermo Chromic Liquid Crystals (TCLC) was used as temperature sensors. A neural network was used to get a calibration curve between the temperature and the color change of the TCLC in order to enhance the dynamic range of temperature measurement. The velocity field measurement was attained by the use of the fray-level images taken for the flow field, and by introducing the cross-correlation technique. The temperature and the velocity fields of the forced and the natural convective flows neat the surface of a cartridge heater were measured simultaneously with the constructed measurement system.

신체 치수 측정기술 특허 동향 분석 (Analysis of Patent Trends for Body Size Measurement Technology)

  • 전영주;소지호
    • 한국인터넷방송통신학회논문지
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    • 제21권5호
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    • pp.209-213
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    • 2021
  • 인체의 체형정보 중 신체 치수 측정기술은 줄자나 영상 분석을 이용한 체형 측정 방법들이 활용되고 있으나, 간편하면서도 측정 정확도나 재현성이 높은 방법에 대한 수요는 꾸준한 상황이다. 본 논문에서는 신체 치수 측정기술과 관련한 국내외 특허 조사를 수행하여 관련 기술의 개발 동향을 파악하였다. WISDOMAIN DB를 이용하여 한국, 미국, 일본 및 유럽에 공개된 특허를 대상으로 검색하였으며, 대분류, 중분류 기술체계와 소분류의 기술범위를 정의하여 유효 특허를 도출하였다. 도출된 특허에 대해 연도별 특허 동향, 국가별 주요 출원인과 기술 분야 현황을 분석하였다. 신체 치수 측정기술 분야는 한국의 특허출원 비중이 높아 이 분야에서 한국이 특허 출원을 주도하는 것으로 나타났다. 센서형 측정기술 분야의 특허 출원 건수 자체가 많지는 않았지만, 측정 간편성 부분에 장점이 있으므로 관련 기술개발은 체성분 분석 관련 측정 정확도 향상에 기여가 가능할 것으로 판단된다.

Laser Diagnostic in a Plasma Display Panel Discharge Cell

  • Choi, Young-Wook
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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    • pp.21-22
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    • 2000
  • Laser diagnostic method in a plasma display discharge cell was introduced. The information of electric field, potential and electron temperature et al. in the surface of plasma display panel can be measured using laser induced fluorescence spectroscopy. However, because of the very small discharge dimension of ${\sim}$ 100 ${\mu}m$, the measurement attempt has almost not been performed. In this paper, the direct measurement possibility of the parameters and the recent work of electric field measurement are demonstrated in the plasma display panel.

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Field monitoring of wind effects on a super-tall building during typhoons

  • Zhi, Lunhai;Li, Q.S.;Wu, J.R.;Li, Z.N.
    • Wind and Structures
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    • 제14권3호
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    • pp.253-283
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    • 2011
  • This paper presents the field measurement results of wind effects on a super-tall building (CITIC Plaza, 391 m high) located in Guangzhou. The field data such as wind speed, wind direction and acceleration responses were simultaneously and continuously recorded from the tall building by a wind and vibration monitoring system during two typhoons. The typhoon-generated wind characteristics including turbulence intensity, gust factor, peak factor, turbulence integral length scale and power spectral density of fluctuating wind speed were presented and discussed. The dynamic characteristics of the tall building were determined based on the field measurements and compared with those calculated from a 3D finite element model of the building. The measured natural frequencies of the two fundamental sway modes of the building were found to be larger than those calculated. The damping ratios of the building were evaluated by the random decrement technique, which demonstrated amplitude-dependent characteristics. The field measured acceleration responses were compared with wind tunnel test results, which were found to be consistent with the model test data. Finally, the serviceability performance of the super-tall building was assessed based on the field measurement results.

Hall probe를 이용한 비접촉 임계전류 측정 (Non-contact critical current measurement using hall probe)

  • 김호섭;이남진;하동우;백승규;김태형;고락길;하홍수;오상수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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    • pp.7-8
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    • 2009
  • Non-contact critical current measurement apparatus was developed using hall probe which measures the magnetic field distribution across the width of superconducting tape. The hall probe consists of 7 independent hall sensors which lie in a line 600 ${\mu}m$. The difference between maximum and minimum magnetic field in the magnetic filed distribution is a main parameter to determine the critical current. As preliminary research, we calculated the magnetic field intensity at the middle sensor, which is a minimum magnetic field and generated by the circular shielding current modeled by Bean model. We confirmed that there are some parameters that affect on the minimum magnetic field; the distance between superconducting layer and hall sensor, the width of superconducting tape, and the critical current distribution across the width of superconducting tape. Among these parameters, the distance between superconducting layer and hall sensor highly influences on the minimum magnetic field.

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Field Measurements of the New CCTV Tower in Beijing

  • Xu, Y.L.;Zhan, S.;Xia, H.;Xia, Y.;Zhang, N.
    • 국제초고층학회논문집
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    • 제2권3호
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    • pp.171-178
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    • 2013
  • The emergence of a growing number of tall buildings, often with unusual shapes and innovative structural systems, has led to the realization of the need for and the importance of field measurements. The new China Central Television (CCTV) Tower in Beijing is one of tall buildings with a highly unusual shape and a complex structural system, requiring field measurements to identify its dynamic characteristics for the subsequent dynamic analysis of the tower under wind excitation, seismic-induced ground motion and traffic-induced ground motion. The structural system and the finite element model of the CCTV Tower are first introduced in this paper. The computed natural frequencies and mode shapes are then presented as a reference for the field measurement. After introducing the arrangement of the ambient vibration measurement, the field measured natural frequencies and damping ratios of the CCTV Tower are presented and the measured natural frequencies are finally compared with the computed ones. It was found that the structural damping ratios of the CCTV Tower are small and the computed natural frequencies are smaller than the measured ones by about 12~17%.