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 38 for “"signal loss"”.
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Mitigated Motion-Induced Signal Loss and Enabled Refractive Index Measurement in Optical Coherence Tomography
… Despite this ability, OCT is known to lose signal when measuring moving objects. Since laser welding is volatile and prone to sporadic motion, it is hypothesized that signal is lost when monitoring laser welding. Therefore, this thesis implements an augmented OCT configuration in the form of …
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Investigating escape of low MW siloxanes from PDMS matrix in aqueous solution
… group also found that the sensors experienced signal loss over time when stored in air. The purpose of this investigation was to explore the loss of signal over time of the sensor when stored in aqueous solution. The signal reduction over time in environments similar to the body could be …
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Understanding and measuring flow in aortic stenosis with MRI
… interrogate the error. It was determined that signal loss, due to intravoxel dephasing, decreased the reliability of the measured forward ow jet velocities. Extreme signal loss in the jet eventuated in salt and pepper noise, which, with a mean velocity of zero, resulted in the underestimation. …
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Strategies for Artifact Correction and Motion Monitoring in MRI Through Innovations in Radiofrequency Coil Design
… artifacts such as geometric distortions and signal loss. B_0 inhomogeneities can be corrected through a process called shimming, which generates magnetic field patterns that have a similar spatial distribution but are opposite in polarity. 2\nd order spherical harmonic shimming is used on …
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Characteristic Raman Bands of Amino Acids and Halophiles as Biomarkers in Planetary Exploration
… cycling resulted in a maximum of 20 % biomarker signal loss for AA. Halophilic microbes survived UV exposure up to 3.5 sols, though with a complete biomarker signal loss. However, cell counts and hence, survival in near surface, freeze-thaw conditions (indicative of RSL conditions) remained …
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Implementation Of Path Planning Methods To Detect And Avoid GPS Signal Degradation In Urban Environments
… these autonomous vehicles are prone to GPS signal loss in urban environments due to obstructions that cause scintillation, multi-path, and shadowing. These effects that decrease the GPS functionality can deteriorate the accuracy of GPS positioning causing losses in signal tracking leading to …
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Laboratory Electrical DC Resistivity of Serpentinite, Graphite, Oxide and Sulfide Minerals
… its inverse, resistivity) is related to radar signal loss. The samples were characterized by analyzing the hand specimens and by using a petrographic microscope. Semi quantitative chemical composition has been assessed by using a Scanning Electronic Microscope (SEM) attached to an Electron …
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Multimodality Imaging of Tumor Vasculature and Metabolism
… to be inhomogeneous across the tumors. Sparse signal loss was observed on the T2 weighted images after the administration of SPIO-PGN635. The signal loss fraction indicated significantly more increase in the irradiated tumor compared to the non-irradiated side. Prussian blue staining confirmed …
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Improvements to Enhance The Security and Reliability of Crowdsourced Spectrum Access Systems and Cognitive Radio Networks
… (RF-OOAI) method distinguishes environmental signal loss from intentional misreporting, preserving the reputation of honest users. These contributions collectively improve the accuracy, efficiency, and robustness of shared spectrum systems, advancing the design and reliability of CRNs and SASs …
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Predicting microwave diffraction in the shadows of buildings
… for accurate computer-based predictions of signal loss due to shadowing. This thesis is intended to fill a need for prediction methods that exploit a building database and consider the three-dimensional profile of the radio path. Models are presented that allow the application of …
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GIS and Satellite Visibility: Viewsheds from Space
… considering terrain or structures that block GPS signals, a major issue in mountainous and urban areas. This paper describes a new Geographic Information Systems (GIS) tool, a customization of ArcGIS named Satellite Viewsheds, which predicts satellite visibility for any place and time while …
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Substrate Impurity Incorporation Mitigation for Improved AlGaN/GaN-ON-Si RF Performance
… path dissipates the radio-frequency (RF) signal, which increases with operation frequency, in transistors manufactured on such a lossy Si substrate and large TDD AlN nucleation layer. As a result, they fail to deliver good RF amplifier performance at high frequency in terms of gain, power, …
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Design for ESD Reliability in High-Frequency Mixed-Signal Integrated Circuits
… performance. The ESD noise, defined as the loss introduced by ESD stress and protection network, can be caused by three mechanisms: I/O protection induced signal loss, mixed-signal coupling through power protection circuits, and latent damage. In this work, we have presented the …
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Conductive PEDOT:PSS fibres for modelling and assessing oligodendrocyte ensheathment
… thereby preventing ion leakage and minimising signal loss. The loss of the myelin sheath can lead to physical and mental health issues, including disabilities and depression. Consequently, there is a pressing need for in-vitro models to investigate oligodendrocyte ensheathment behaviour. …
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Multifocal Multiphoton Microscopy for Neurobiological Imaging
… Early MMM had very limited imaging depth due to signal-to-noise ratio (SNR) degradation resulting from the scattering of emission photons in highly turbid biological specimens. The development of descanned MMM with multianode photomultiplier tube has partly alleviated this problem, but it still …
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The Steered Auxiliary Beam Canceller for Interference Cancellation in a Phased Array
A common problem encountered in phased array signal processing is how to remove sources of interference from a desired signal. Two existing methods to accomplish this are the Linearly Constrained Minimum Variance (LCMV) beamformer and the Side-Lobe Canceller (SLC). LCMV provides better performance …
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Mechanical and optical behavior of a novel optical fiber crack sensor and an interferometric strain sensor
… sheet which induces fiber bending leading to signal loss. Monitoring the backscattered signal provides crack opening size and location. A theoretical model for optical fiber loss prediction is developed based on a combination of mechanical and optical analyses.
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Large-Signal Characterization of Piezoelectric Resonators for Power Conversion
… data to more completely characterize the losses in piezoelectric resonators owing to both mechanical and dielectric effects. To account for mechanical losses, the variation in resonator quality factor is examined across a range of drive levels for multiple resonator sizes, frequencies, and …
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Study of Lorentz Effect Imaging and Neuronal Current MRI Using Electromagnetohydrodynamic Models
… mapping.</p><p>EMHD is a good predictor of LEI signal loss. We can measure the underlying current strength and polarity in the phantom using LEI images. We can also use trends from the EMHD model results to predict the required current density for signal detection in future LEI experiments. We …
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Developing Telecom Band-Compatible Molecular Color Centers for Quantum Networking
… widespread use of quantum networking demands low signal loss and distortion over long distances. To achieve this, prospective materials for quantum networking must emit in fiber optics’ optical communications band defined as 1260 to 1625 nm, commonly known as the “telecom band.” Vanadium dopants …
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