• Title/Summary/Keyword: Height sensor

Search Result 354, Processing Time 0.035 seconds

Design of Distributed Fiber Optic Sensor Net for the Detection of External Sound Frequency (외부 음향 주파수 탐지를 위한 분포형 광섬유 센서망 설계)

  • 이종길
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2003.11a
    • /
    • pp.792-796
    • /
    • 2003
  • In this paper, to detect external sound frequency on the latticed structure, fiber optic sensor net using Sagnac interferometer was fabricated and tested. The latticed structure fabricated with dimension of 50cm in width and 50cm in height, the optical fiber, 50m in length, distributed and fixed on the latticed structure. Single mode fiber, a laser with 1,550nm in wavelength, 2${\times}$2 coupler were used. External sound signal applied to the fiber optic sensor net and the detected optical signals were compared and analyzed to the detected microphone signals against time and frequency domain. Based on the experimental results, fiber optic sensor net using Sagnac interferometer detected external sound frequency, effectively. This system can be expanded to the structural health monitoring system.

  • PDF

Detection of External Sound Frequency by Using the Distributed Fiber Optic Sensor Net (분포형 광섬유 센서망을 이용한 외부 음향 주파수 탐지)

  • 이종길
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.14 no.7
    • /
    • pp.569-576
    • /
    • 2004
  • In this paper, to detect external sound frequencies on the latticed structure, fiber optic sensor net using Sagnac interferometer was fabricated and tested. The latticed structure was fabricated with a dimension of 50 cm in width and 50 cm in height. The optical fiber of 50m in length was distributed and fixed on the surface of the latticed structure. Single mode fiber, a laser with 1,550 nm in wavelength, 2 ${\times}$ 2 coupler were used. External sound signal, 240 Hz, 495 Hz, 1.445 kHz, 2k Hz, applied to the fiber optic sensor net and the detected optical signals were compared to the detected microphone signals against time and frequency domains. Based on the experimental results, fiber optic sensor net using Sagnac interferometer detected external sound frequency, effectively. This system can be expanded to the structural health monitoring system.

TROPICAL TREE MORPHOLOGY USING AIRBORNE LIDAR DATA

  • JANG, Jae-Dong;Yoon, Hong-Joo
    • Proceedings of the KSRS Conference
    • /
    • v.2
    • /
    • pp.676-679
    • /
    • 2006
  • Mangrove crowns were delineated using active sensor LIDAR (LIght Detection And Ranging) data by a crown delineating model developed in this study. LIDAR data were acquired from airborne survey by a helicopter for the estuary of Macouria in the northeast coast of French Guiana. The canopy height image was derived from LIDAR vector data by calculating the difference between ground and non-ground data. The mangrove site in the study area was classified to three sectors by the time of mangrove settlement; Mangrove 1986, 2002 and 2003. The estimated crown of Mangrove 1986 was reliable defined for their size, number and volume because of larger crown size and bigger variation of crown height. The tree crown size of Mangrove 2002 and 2003 by the model was overestimated and the number of trees was much underestimated. The estimated crown was not for single crown but a crown group due to homogenous crown height and spatial resolution of LIDAR data. However the canopy height image derived from LIDAR data provided three-dimensional information of mangroves.

  • PDF

Analysis of Ground Height from Automatic Correlation Matching Result Considering Density Measure of Tree (수목차폐율을 고려한 자동상관매칭 수치고도 결과 분석)

  • Eo, Yang-Dam
    • Spatial Information Research
    • /
    • v.15 no.2
    • /
    • pp.181-187
    • /
    • 2007
  • To make digital terrain data, automatic correlation matching by stereo airborne/satellite images has been researched. The result of automatic correlation matching has a limit on extracting exact ground height because of angle of sensor, tree of height. Therefore, the amount of editing works depend on the distribution of spatial feature in images as well as image quality. This paper shows that the automatic correlation matching result was affected by density and height of tree.

  • PDF

Compact Doppler Sensor Using Oscillator Type Active Antenna (능동 발진 안테나를 이용한 소형 도플러 센서)

  • Yun, Gi-Ho
    • Journal of IKEEE
    • /
    • v.15 no.1
    • /
    • pp.49-56
    • /
    • 2011
  • In this paper, a compact doppler sensor with oscillator type active antenna operating at 2.4GHz frequency band is proposed to measure the distance or speed of a moving object. The active antenna has been realized by oscillator using radiator, patch antenna, as its resonator. The oscillation frequency is shifted depending on approaching of the object, and a detection circuit discriminates the frequency deviation. The oscillator type active antenna has been designed and simulated. The prototype fabricated has a very small circular disk type of diameter 30mm and height 4.2mm. As for antenna performance, broadside radiation pattern with beamwidth of $130^{\circ}$ and oscillation frequency of 2.373GHz has been measured. Test results as a doppler sensor shows that doppler signal voltage of about 190mV has been obtained for conducting plate moving 1 meter away from the sensor. And, doppler signal voltage has been linearly increased to the ground from 4.5m height by free-falling the sensor.

Compact Range Detection Sensor by Oscillation Frequency Deviation of an Active Antenna (능동안테나의 발진주파수 편이에 의한 소형 거리 센서)

  • Yun, Gi-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.15 no.3
    • /
    • pp.528-535
    • /
    • 2011
  • In this paper, a compact doppler sensor with oscillator type active antenna operating at 2.4GHz frequency band is proposed to measure the distance to a moving object. The oscillation frequency is shifted depending on approaching of the object, and a detection circuit discriminates the frequency deviation. The active antenna has been designed and simulated. The prototype fabricated has a small circular disk type of diameter 30mm and height 4.2mm. As for antenna performance, broadside radiation pattern with beamwidth of $120^{\circ}$ and oscillation frequency of 2.35GHz has been measured. Test results as a range sensor shows that signal voltage of about 240mV has been obtained for conducting plate moving 1 meter away from the sensor. And, signal voltage has been linearly increased to the ground from 5m height by free-falling the sensor.

The Study of Applicability to Fixed-field Sensor for Normalized Difference Vegetation Index (NDVI) Monitoring in Cultivation Area

  • Lee, Kyung-Do;Na, Sang-Il;Baek, Shin-Chul;Jung, Byung-Joon;Hong, Suk-Young
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.48 no.6
    • /
    • pp.593-601
    • /
    • 2015
  • The NDVI (Normalized difference vegetation index) is used as indicators of crop growth situation in remote sensing. To measure or validate the NDVI, reliable NDVI sensors have been needed. We tested new fixed-field NDVI sensor, "SRS (Spectral Reflectance Sensor)" developed by Decagon Devices, during Kimchi cabbage growing season at the cultivation area located in Gochang, Gangneung and Taebaek in Korea from 2014 to 2015. The diurnal variation of NDVI measured by SRS (SRS NDVI) showed a slight ${\cap}$-profile shape and was affected by water on the sensor surface. This means that SRS NDVI around noontime is resonable, except rainy day. Comparisons were made between the SRS NDVI and NDVI of used widely mobile sensor (Cropcircle NDVI). The comparisons indicate that SRS NDVI are close to Cropcircle NDVI (R=0.99). SRS NDVI time series displayed change of the plant height and leaf width of Kimchi cabbage. An obvious exponential relationship is found between SRS NDVI and the plant height ($R^2{\geq}0.92$) and leaf width ($R^2{\geq}0.92$) of Kimchi cabbage. Thus, SRS NDVI will be used as indicator of crop growth situation and a very powerful tool for evaluation of remote sensing NDVI estimates and associated corrections.

Study of Failure Examples of Automotive Electronic Control Suspension System Including Cases with Wiring Disconnection and Air Leakage (배선 단선과 에어 누설에 관련된 자동차 ECS 시스템의 고장사례 고찰)

  • Lee, Il Kwon;Park, Jong Geon;Shin, Myung Shin;Jang, Joo Sup
    • Tribology and Lubricants
    • /
    • v.29 no.3
    • /
    • pp.180-185
    • /
    • 2013
  • The purpose of this study was to analyze the tribological characteristics of the Electronic control suspension System in a car. In the first example, the cilp used to attach the front electronic control suspension(ECS) system's control actuator was fastened very tightly. Thus, the wire was cut because of continual rotation of the shock-up shover piston rod used to adjust the height of the car. This verified the disconnection phenomenon where wire damaged makes it impossible for the ECS system to send signal to the actuator. The second example, involved a minute hole that allowed gas to leak from the ECS system. As a result, the height of the car verified the down phenomenon. In the third example, the resistance of a wire measured at $0.21{\Omega}$, when the G sensor was disconnected from the system. This verified the system shutdown and lighting of the ECS warning lamp because of body interference caused by a slight pressure on the battery cover. Therefore, quality control is always necessary to ensure safety and durability of a car.

A study on waveforms with press conditions of Harness terminal (단자(Terminal) 압착조건에 따른 파형의 고찰)

  • Shin, Young-Lok;Yang, Yun-Suk;Kim, Chul-Han;SaGong, Geon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2000.04b
    • /
    • pp.172-175
    • /
    • 2000
  • The crimping connection is a permanent connection that maintains mechanical and electrical property for a long time by crimping two conductors. In this paper, we have done a basic study to decide normal or abnormal condition depending on crimping. Using PZT piezo-sensor, we have analyzed crimping waveforms according to the crimping height. And hence the normal or abnormal condition of crimping connections in real time could be decided by comparison of crimping waveforms in the cases of normal crimping, over crimping, under crimping and core omitting.

  • PDF

$CH_4$ Gas Sensor Utilizing Pd-SiC Schottky Diode (Pd-SiC 쇼트키 다이오드를 이용한 $CH_4$ 가스센서)

  • 김창교;이주헌;이영환
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1998.11a
    • /
    • pp.163-166
    • /
    • 1998
  • The mechanism of methane sensing by Pd-SiC diode was investigated over the temperature range of 400~$600^{\circ}C$. The effects or methane gas reaction on the parameters such as barrier height, initial rate of methane gas reaction are investigated. The methane gas reaction kinetics on the device are also discussed. The physical and chemical mechanism responsible for methane detection are proposed. Analysis of steady-state reaction kinetics using I-V method confirmed that methane gas reaction processes are responsible for the barrier height change in the diode.

  • PDF