• Title/Summary/Keyword: Multi-beam sensor

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Study on Development of Side Scan Sonar Using Multi-beam Sensors (다중 빔 센서를 이용한 측면주사음탐기에 관한 연구)

  • Chang, Y.S.;Keh, J.E.;Park, S.S.;Lee, M.H.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.317-318
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    • 2006
  • The towfish oi a side scan sonar is an equipment that search images of the bottom surface of the sea in real time. It is a typical equipment that is related to a sea investigation such as a geological survey, seabed communication cable and power line cable placing repair investigation, fish breeding ground investigation, sea purification, relic and mineral investigation, and mine and submarine search. It used to find objects and Investigate on the seabed surface. But, recently, it is used to sea purification and geological survey that require information of the correct surface of the seabed. So, it needs various filtering technique and image processing techniques development to acquire high resolution image. Therefore, this research develops a side scan sonar using multi-beam sensors that supply various information with the fast scan speed and correct high resolution that is not a simple underwater investigation equipment.

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Simultaneous and Multi-frequency Driving System of Ultrasonic Sensor Array for Object Recognition

  • Park, S.C.;Choi, B.J.;Lee, Y.J.;Lee, S.R.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.582-587
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    • 2004
  • Ultrasonic sensors are widely used in mobile robot applications to recognize external environments, because they are cheap, easy to use, and robust under varying lighting conditions. However, the recognition of objects using a ultrasonic sensor is not so easy due to its characteristics such as narrow beam width and no reflected signal from a inclined object. As one of the alternatives to resolve these problems, use of multiple sensors has been studied. A sequential driving system needs a long measurement time and does not take advantage of multiple sensors. Simultaneous and pulse coding driving system of ultrasonic sensor array cannot measure short distance as the length of the code becomes long. This problem can be resolved by multi-frequency driving of ultrasonic sensors, which allows multi-sensors to be fired simultaneously and adjacent objects to be distinguished. Accordingly, this paper presents a simultaneous and multi-frequency driving system for an ultrasonic sensor array for object recognition. The proposed system is designed and implemented using a DSP and FPGA. A micro-controller board is made using a DSP, Polaroid 6500 ranging modules are modified for firing the multi-frequency signals, and a 5-channel frequency modulated signal generating board is made using a FPGA. To verify the proposed method, experiments were conducted in an environment with overlapping signals, and the flight distances for each sensor were obtained from filtering of the received overlapping signals and calculation of the time-of-flights.

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A Study on MBES Error Data Removing using Motion Sensor (Motion Sensor를 이용한 MBES 오측자료 제거 연구)

  • Kang, Moon-Kwon;Choi, Yun-Soo;Chang, Min-Chol;Yoon, Ha-Su
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.1
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    • pp.39-46
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    • 2010
  • Sounding data is the essential source for the safety of ships navigation system, and fundamental to the reasonable usage and maintenance of the ocean as well. As IT tech, positioning equipment such as GPS and INS, echo sounder are developed, recently, the precise submarine topography database bas been built by Multi-Beam Echo Sounder. However, MBES data includes some inevitable error caused by several factor, and some data have errors where the terrain is wobble. The error, which causes the $moir\acute{e}$ pattern error is the main factor hindering the accuracy of MBES data results, and therefore it is necessary to figure out the main cause of the error for the improvement of the accuracy by removing error data. On this research, the main cause of the error data is studied by analyzing motion sensor value of data including the $moir\acute{e}$ pattern error. Thus, as the result of examination, it turns out that the $moir\acute{e}$ pattern error is related to the standard deviation of Roll, and error data values are results of the non-correspondence between Swath data and Roll values caused by the drastic change of Roll values. Accordingly, the error data is removed by comparing between the gradient of Swath data and Roll values. Finally, as the result of removing error data, it is expected to be able to estimate the quality of MBES using the standard deviation of Motion sensor's Roll value, and calculate the additive error factor, which minimize non-corresponding data, and also this research must be contributed to improve the accuracy of sounding for small vessels with lots of motion in the bad circumstance for navigation.

Mathematical model for assessment of the safety of over three-span steel beams based on average strains from long gage optic sensor (평균변형률을 이용한 3경간 이상 연속 철골보의 안전성 평가 기법)

  • Jung Seong-Moon;Lee Hong-Min;Park Hyo-Seon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.159-166
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    • 2006
  • Although the strain distribution along the length of a beam in buildings or infrastructures is non-uniform, most fiber optic sensors are point sensors that can measure the strain only at a local point of a beam. Long gage fiber optic sensors that measure integrated strain over a relatively long length can consider strain variation. This type of sensor was found to be efficient and useful for monitoring large-scale structures. On the other hand, the maximum strain or stress in a beam can not be measured with long gage optic sensors. However, for the assessment of the safety of multi-span steel beams subjected to various vertical loads, the maximum strain or stress measured during monitoring is required for comparison with the allowable stress of the beam calculated by a design code. Therefore, in this paper, mathematical models are presented for determination of the maximum values of strains in more three-span steel beams based on the average strains measured by long gage optic sensors.

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Electrode Shape Optimization of Piezo Sensors Using Genetic Algorithm (유전 알고리듬을 이용한 압전센서의 전극형상 최적화)

  • Lee Ki-Moon;Park Hyun-Chul;Park Chul-Hue
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.6 s.249
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    • pp.698-704
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    • 2006
  • This paper presents an electrode shape design method for the multi-mode sensors that could deteict the selected structural multiple modes. The structure used for this study is an isotropic cantilever beam type with a PVDF (polyvinylidene fluoride) which is bonded onto the structure as a sensor. The shape optimization problem is solved by using Genetic Algorithm (GA) with an appropriate objective function. The performance of analytical optimal shape sensor is compared with that of experimental work. The results show that the, obtained electrode shape sensors have good performance to detect the multiple vibration modes simultaneously.

The Development of the Beam Rotating Actuator Based on the Bimorph Piezo Material (Bimorph 피에조 소자를 이용한 빔 회전 구동기의 개발)

  • 이정현;한창수;김수현;곽윤근
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.450-453
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    • 1995
  • The beam rotating actuator, which can be utilized to improve the data transfer rate for the optical disk systems, has been developed. It can employ a newly developed laser beam rotating actuator for putting multi-beam spots on more than one track on the optical disk simultaneously. Therefore, It has to maintain up to .+-.0.01 .deg. resolution and high bandwidth performance. In this these, the Dove prism is used for the beam rotating actuator based on bimorph piezo material. The performance of the beam rotating actuator is verified since the dynamics ferquency performance is measured using the dynamic analyzer and the attached stain gage sensor. the beam rotating angle performance is also examined since the long range beam reflection character is utilized.

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An Experimental Study of Injection Molding for Multi-beam Sensing Lens Using The Change of Gate Geometry (금형 게이트 크기 변화에 따른 멀티빔 센서용 렌즈 사출성형성 향상에 관한 연구)

  • Cho, S.W.;Kim, J.S.;Yoon, K.H.;Kim, J.D.
    • Transactions of Materials Processing
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    • v.20 no.5
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    • pp.333-338
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    • 2011
  • Rapidly developing IT technologies in recent years have raised the demands for high-precision optical lenses used for sensors, digital cameras, cell phones and optical storage media. Many techniques are required to manufacturing high-precision optical lenses, including multi-beam sensing lenses investigated in the current study. In the case of injection molding for thick lenses, a shrinkage phenomenon often occurs during the process. This shrinkage is known to be the main reason for the lower optical quality of the lenses. In the present work, a CAE analysis was conducted simultaneously with experiments to understand and minimize this phenomenon. In particular, the sectional area of a gate was varied in order to understand the effects of packing and cooling processes on the final shrinkage pattern. As a result of this study, it was demonstrated that a dramatic reduction of the shrinkage could be obtained by increasing the width of the gate.

Design and Fabrication of SiO2/TiO2 Multi Layer Thin Films on Silicon Encapsulation of LED Deposited by E-beam Evaporation for NIR Narrow Band Pass Filter Application (NIR 협대역 투과 필터 응용을 위한 LED 실리콘 봉지재 위에 직접 E-beam으로 증착 된 SiO2/TiO2 다층 박막 설계 및 제작)

  • Kim, Dong Pyo;Kim, Kyung-Seob;Kim, Goo-Cheol;Jeong, Jung-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.2
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    • pp.165-171
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    • 2022
  • The SiO2/TiO2 multilayer thin films used for narrow band pass filter were fabricated using E-beam evaporation method. The narrow band pass filter was used to enhance the resolution of spectroscopy and sensor applications with near infrared (NIR) light source. The narrow band pass filter with multilayer thin films were designed with Essential Macleod program. The multilayers of SiO2/TiO2 with 32 layers were deposited on the silicon encapsulation of IR with peak wavelength (λp) of 660 nm and NIR LEDs with λp of 830 nm, 880 nm, and 955 nm. After NIR light passed through the narrow band pass filter, the full width of half maximum of 33.4~48.6 nm became narrow to 20~24 nm owing to the absorption of photons with short or long wavelength of designed band of 20 nm. The SiO2/TiO2 band pass filter fabricated in this study can be used for sensor, optoelectronics, and NIR spectroscopy applications.

Active Vibration Control of Fixed-Fixed Beam Using Piezoelectric Sensor and Actuator (압전 감지기와 작동기를 이용한 양단 고정보의 능동 진동 제어)

  • 한상보;곽문규;최이호;윤신일
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.260-265
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    • 1996
  • Active control of forced vibration response of a fixed-fixed beam implementing PZT sensor/actuator was conducted. Among various control scheme, PPF control was chosen due to its amenability and natural robustness. For a single frequency excitation, the PPF control provided reasonable controllability with the appropriate damping ratio of the compensator. Without increasing actuator voltage, best controllability can be obtained by the exact tuning between the natural frequency of the structure and the cut-off frequency of the compensator. Even the multi-frequency excitation, the PPF provided good vibration suppression for corresponding mode of interest, even though residual modes should be controlled with independent compensators for each mode.

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Experimental validation of a multi-level damage localization technique with distributed computation

  • Yan, Guirong;Guo, Weijun;Dyke, Shirley J.;Hackmann, Gregory;Lu, Chenyang
    • Smart Structures and Systems
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    • v.6 no.5_6
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    • pp.561-578
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    • 2010
  • This study proposes a multi-level damage localization strategy to achieve an effective damage detection system for civil infrastructure systems based on wireless sensors. The proposed system is designed for use of distributed computation in a wireless sensor network (WSN). Modal identification is achieved using the frequency-domain decomposition (FDD) method and the peak-picking technique. The ASH (angle-between-string-and-horizon) and AS (axial strain) flexibility-based methods are employed for identifying and localizing damage. Fundamentally, the multi-level damage localization strategy does not activate all of the sensor nodes in the network at once. Instead, relatively few sensors are used to perform coarse-grained damage localization; if damage is detected, only those sensors in the potentially damaged regions are incrementally added to the network to perform finer-grained damage localization. In this way, many nodes are able to remain asleep for part or all of the multi-level interrogations, and thus the total energy cost is reduced considerably. In addition, a novel distributed computing strategy is also proposed to reduce the energy consumed in a sensor node, which distributes modal identification and damage detection tasks across a WSN and only allows small amount of useful intermediate results to be transmitted wirelessly. Computations are first performed on each leaf node independently, and the aggregated information is transmitted to one cluster head in each cluster. A second stage of computations are performed on each cluster head, and the identified operational deflection shapes and natural frequencies are transmitted to the base station of the WSN. The damage indicators are extracted at the base station. The proposed strategy yields a WSN-based SHM system which can effectively and automatically identify and localize damage, and is efficient in energy usage. The proposed strategy is validated using two illustrative numerical simulations and experimental validation is performed using a cantilevered beam.