Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"Acoustic sensor"”.
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An acoustic sensor for measuring traffic variables
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.
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Efficient Communication Protocols for Underwater Acoustic Sensor Networks
Underwater sensor networks find applications in oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation, tactical surveillance, and mine reconnaissance. The enabling technology for these applications is acoustic wireless networking. …
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Development of acoustic sensor and signal processing technique.
… the development of low-cost, rapidly deployable acoustic base sensor that will be able to survey live sewer pipes. The sensor emits short coded acoustic signals which are reflected from any defects of the wall of the underground pipes and recorded for future processing. The processing algorithms …
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Unattended acoustic sensor systems for noise monitoring in national parks
Detection and classification of transient acoustic signals is a difficult problem. The problem is often complicated by factors such as the variety of sources that may be encountered, the presence of strong interference and substantial variations in the acoustic environment. Furthermore, for most …
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Fiber inline pressure and acoustic sensor fabricated with femtosecond laser
"Pressure and acoustic measurements are required in many industrial applications such as down-hole oil well monitoring, structural heath monitoring, engine monitoring, study of aerodynamics, etc. Conventional sensors are difficult to apply due to the high temperature, electromagnetic-interference …
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Partial Discharge Detection and Localization in High Voltage Transformers Using an Optical Acoustic Sensor
… observable signals including electric and acoustic pulses and is currently detected using a host of exterior measurement techniques. These techniques include electrical lead tapping and piezoelectric transducer (PZT) based acoustic detection. Many modern systems use a combination of these …
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Development of Ionic Polymer Metallic Composites as sensors
… in engineering or biomedical applications as sensors or actuators. Most commonly they are used for mechanical actuation, as they have the ability to generate large bending strains and moderate stress under low applied voltages. Although the actuation capabilities of IPTs have been extensively …
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Design and implementation of a non-contact microwave level measument instrument
… transceiver had to be designed to replace an acoustic sensor on an existing 4-20 mA loop powered ultrasonic instrument and had to be compatible with its on-board acoustic signal processing hardware. Specifications are developed for a pulsed radar architecture operating at 5.8 GHz with a …
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Underwater Direction-of-Arrival Finding: Maximum Likelihood Estimation and Performance Analysis
… of direction-of-arrival: DOA) finding using acoustic sensor arrays in underwater scenarios, and develop novel signal models, maximum likelihood: ML) estimation methods, and performance analysis results. We first examine the underwater scenarios where the noise on sensor arrays are spatially …
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Development of Novel Optical Fiber Interferometric Sensors with High Sensitivity for Acoustic Emission Detection
… new highly-sensitive and reliable fiber optical acoustic sensor capable of real-time on-line detection of acoustic emissions in power transformers, this dissertation presents the comprehensive research work on the theory, modeling, design, instrumentation, noise analysis, and performance …
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Fiber-Optic Michelson Interferometer with Faraday Mirrors for Acoustic Sensing using a 3 × 3 Coupler and Symmetric Demodulation Scheme
For the past 40 years, acoustic sensing has been a major avenue for the growth of interfero- metric fiber-optic sensors. Fiber-optic acoustic sensors have found uses in military, commer- cial, and medical applications. An interferometric fiber-optic acoustic sensor is presented utilizing the …
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Advanced Time Domain Sensing For Active Structural Acoustic Control
… in the past decade. In Active Structural Acoustic Control (ASAC), the minimization of sound radiation is achieved by modifying the response of the structure through structural inputs rather than by exciting the acoustic medium (Active Noise Control, ANC). The ASAC technique often produces …
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Evaluation of an acoustic detection algorithm for reactive collision avoidance in underwater applications
… a vehicle detection algorithm based on a passive acoustic sensor, intended for autonomous collision avoidance in Unmanned Underwater Vehicles. By placing a hydrophone at a safe distance from a dock, it was possible to record the acoustic signature generated by a small motor boat as it navigated …
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Design and characterization of a smart bit for in-situ force measurement, using capacitive load cells and acoustic spectra analysis to determine rock type and tool wear in rock excavation process
… interface to do so. Vibration frequencies, acoustic emissions, and cutting forces are all known to vary with rock type and tool wear conditions, and this work captures those changes with varied cutting test conditions. Three different sensor designs were tested: a capacitive load cell with …
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DATA FUSION ARCHITECTURES FOR UNDERSEA WARFARE WITH AUTONOMOUS UNDERWATER VEHICLES
… of combining mobile and stationary underwater sensors into a coherent, distributive network. This project presents a baseline architecture for a data fusion system that facilitates the near real-time exchange of information from disparate sources. This architecture, in turn, provides a basis …
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INCREASED SPEED AND ENDURANCE OF ADVANCED MULTI-COPTERS THROUGH THE USE OF SIDE THRUSTERS
… designed to float on the ocean, deploying an acoustic sensor at depth, in support of anti-submarine warfare operations, filling the same role as a sonobuoy but with added air mobility. It uses a solar array for power production to gain energy independence, but the array degrades cruise flight …
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Acoustic wireless sensing for environmental monitoring
… its existence. In this research, an electronic sensor has been developed in order to detect the presence of EHB larvae in timber. Only an accurate detection can allow for selective treatment, which is required in order to eliminate the pest. In the past no reliable detection methods were …
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Bio-inspired acoustic sensors and systems - from biology to engineering exploiting feedback computation
In order to design sensors and systems that can be sensitive to small signal levels even when immersed by background noise, may require out-of-the-box thinking. Biology can provide inspiration to achieve that, allowing the engineering landscape to borrow interesting ideas with the aim to solve …
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Robot design for leak detection in water-pipe systems
… robotic platform that carries the necessary sensor and travels inside the water pipe systems. To begin with, experiments were carried out to investigate the suitability of using acoustic sensor to detect the leaks and favorable results were obtained. Then design specification of the mobile …
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