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 42 for “"System Noise"”.
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Optimisation of computed radiography chest imaging utilising a novel simulation technique derived from real patient computed tomography data sets
To optimise any medical digital imaging system for chest radiography, it is vital that the images used for optimisation contain projected anatomy, or in other words, anatomical noise. In this thesis, a method to produce and validate a digitally reconstructed radiograph (DRR) computer algorithm that …
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Breast Tomosynthesis: Aspects on detection and perception of simulated lesions
… The first study concerned the effect of system noise on the detection of masses and microcalcification clusters in DM images using a free-response task. System noise has an impact on image quality and is related to the dose level. It was found to have a substantial impact on the detection …
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Load Balancing Regular Meshes on SMPS with MPI
… strategies often do not consider the inherent system noise which can hinder MPI application scalability to emerging peta-scale machines with 10000+ nodes. In this work, we suggest a solution that uses a tunable hybrid static/dynamic scheduling strategy that can be incorporated into current MPI …
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Optimal fault detection and resolution during maneuvering for Autonomous Underwater Vehicles
… autonomous vehicles must detect debilitating system control faults. Prior model-based observer design for 21UUV was analyzed using actual vehicle sensor data. It was shown, based on experimental response, that residual generation during maneuvering was too excessive to detect manually …
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Characterization Of Critical Network Components Of Coupled Oscillators
… of the components of the network, and system noise is investigated.
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Modulation Technique for Magneto -Optic Imaging of Weak Magnetic Fields With Rare-Earth Iron Garnet Films
… of a room-temperature magnetic field detection system capable of measuring fields as low as 1 nT and with 500 mum spatial resolution. Such an instrument is of interest for biomagnetic imaging, including magnetocardiography for diagnosis of cardiac anomalies and imaging of magnetic nanoparticles …
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Attitude Determination and Control of Nano-Satellites
… to be accomplished on this bus. To complete the system, an accurate attitude determination system needs to be developed. Several methods for determining the attitude state as well as mitigating system noise are explored. In particular, an extended Kalman lter is developed to obtain accurate …
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Phase-locking terahertz quantum cascade lasers for high dynamic range heterodyne imaging
… necessitate the development of an imaging system capable of extracting small terahertz signals from the background noise. This can be achieved using a combination of heterodyne detection and a phase-locked loop to selectively lower the system noise floor while preserving signal power. In …
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Estimation of nonlinear systems using Jump Matrix Technique
An estimator for Nonlinear system estimation using Jump Matrix Technique is developed. The idea of the Jump Matrix Technique is to break up the nonlinear system into linear and nonlinear subsystems. The linear subsystem projection, during the sampling interval, is on the basis of the transition …
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Development of Methodology for Achieving Reliable GPS Performance In 3G Handset Noisy Environments
<p>The co-existence of Global Positioning System services (GPS) with cellular, other services and features in mobile handset, presents challenges to GPS performance. Particularly challenging is the over-the-air (OTA) interface to the GPS receiver that results from carriers like the Global System …
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A photophonic instrument concept to measure atmospheric aerosol absorption
… had sufficient sensitivity and low enough system noise to measure an absorption coefficient of about 10⁻⁶/meter. Methods of signal improvement and noise reduction were discussed and tested. The results showed the instrument could measure absorption coefficients within the range expected by …
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ISM S-band CubeSat Radio Designed for the PolySat System Board
… CubeSat leads to the conclusion that this system will require a large deployable CubeSat antenna, large earth station satellite dish, and a fine-pointing attitude control system. Noise floor measurements of a CubeSat ground station demonstrate that terrestrial ISM interference can be …
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Reducing synchronization in distributed parallel programs
… and applications for distributed-memory parallel systems face many challenges to attaining high performance. These challenges include communication latency, critical path delay, suboptimal scheduling, load imbalance, and system noise. These challenges are often defined and measured relative to …
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Adaptation of an unused paraboloidal reflector for L-band drift scan observations
… a focal ratio of 0.34, in an L-band radiometer system targeting observations of the neutral hydrogen 21cm line. A coaxial cavity feed horn was implemented using cost-effective manufacturing techniques. The horn is comprised of sheet metal sections and standard aluminum pipe. The antenna’s …
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Self-Calibrated Interferometric/Intensity-Based Fiber Optic Pressure Sensors
… (SCIIB) pressure sensor system. By self-referencing its two channels outputs, for the first time to our knowledge, the developed SCIIB technology can fully compensate for the fluctuation of source power and the variations of fiber losses. Based on the SCIIB principle, both …
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Algorithmic Optimization of Sensor Placement on Civil Structures for Fault Detection and Isolation
… the anomaly is a structural damage, or is due to system noise, sensor failure, or another non-structural event. Having confirmed the presence of a structural anomaly, the second part of the problem, damage isolation, is to determine where that anomaly has occurred.,/p><p>The principles of DDI have …
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RadioSTAR (Radio Spacecraft for Telecommunications Assessment and Risk-reduction): A 3U CubeSat for validation of ground stations and link budgets
… simulate nearly any upcoming spacecraft’s radio system, thus qualifying a ground station’s readiness for on-orbit operations. Furthermore, this spacecraft can be used for refining the link budget design, eliminating uncertainties like proper values to use for system noise temperature. Additional …
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Islanding Detection and Cybersecurity in Inverter-Based Microgrids Under a High-Noise Environment
… the point of common coupling (PCC) under a high-noise environment, focusing on decreasing detection period, zero power mismatch nondetection zone, and power quality degradation. Unlike existing methods, which overlook the noise effect, this study mitigates noise impact on islanding detection. …
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Propulsion system concepts for silent aircraft
The noise emitted by commercial aircraft is a major inhibitor of the growth of commercial air transport and is a critical environmental issue in air transportation. A functionally-silent aircraft is envisioned to achieve a step change in airframe and propulsion system noise reduction (30 EPNdB). …
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Development of novel low noise switch-mode power supply designs for high fidelity audio power amplifiers.
… limit to the reduction of weight in audio power systems. In order to overcome these problems, Switch-mode Power Supplies (SMPS) incorporate high speed switching transistors that allow for much smaller power conversion and energy storage components to be employed. In addition the low power …
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