Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 30 of 30
Full-Text Articles in Engineering
Distributed And Optimal State Estimation For Heterogeneous Dynamic Systems Operating Within A Strongly Connected Network, Matthew Howard
Distributed And Optimal State Estimation For Heterogeneous Dynamic Systems Operating Within A Strongly Connected Network, Matthew Howard
Electronic Theses and Dissertations, 2020-
This dissertation is aimed at developing optimal and distributed state estimation algorithms for a team of cooperating nodes with the goal of improving accuracy through local sharing of relevant information. The nodes are assumed to be individually equipped with heterogeneous sensors for measuring a common target which can be dynamic and time-varying. Additionally, the nodes are assumed to be connected through a dynamically changing communication network modeled as a sequence of strongly connected digraphs allowing for local communication and distributed interactions. Using the data sharing afforded by the communication network, a weighted average state estimate consensus can be found across …
Directional Spectral Solar Energy For Building Performance: From Simulation To Cyber-Physical Prototype, Joseph Del Rocco
Directional Spectral Solar Energy For Building Performance: From Simulation To Cyber-Physical Prototype, Joseph Del Rocco
Electronic Theses and Dissertations, 2020-
The original research and development in this dissertation contributes to the field of building performance by actively harnessing a wider spectrum of directional solar radiation for use in buildings. Solar radiation (energy) is often grouped by wavelength measurement into the spectra ultraviolet (UV), visible (light), and short and long-wave infrared (heat) on the electromagnetic spectrum. While some of this energy is directly absorbed or deflected by our atmosphere, most of it passes through, scatters about, and collides with our planet. Modern building performance simulations, tools, and control systems often oversimplify this energy into scalar values for light and heat, when …
Spectral Dependence Of Deep Subwavelength Metallic Apertures In The Mid-Wave Infrared, Heath Gemar
Spectral Dependence Of Deep Subwavelength Metallic Apertures In The Mid-Wave Infrared, Heath Gemar
Electronic Theses and Dissertations, 2020-
For two decades, extraordinary optical transmission (EOT) has amplified exploration into subwavelength systems. Researchers have previously suggested exploiting the spectrally selective electromagnetic field confinement of subwavelength cavities for multispectral detectors. Utilizing the finite-difference frequency domain (FDFD) method, we examine electromagnetic field confinement in both 2-dimensional and 3-dimensional scenarios from 2.5 to 6 microns (i.e., mid-wave infrared or MWIR). We explore the trade space of deep subwavelength cavities and its impact on resonant enhancement of the electromagnetic field. The studies provide fundamental understanding of the coupling mechanisms allowing for prediction of resonant spectral behavior based on cavity geometry and material properties. …
Acoustoelectric Amplification In Piezoelectric-Silicon Micromachined Lamb Wave Devices, Hakhamanesh Mansoorzare
Acoustoelectric Amplification In Piezoelectric-Silicon Micromachined Lamb Wave Devices, Hakhamanesh Mansoorzare
Electronic Theses and Dissertations, 2020-
In this dissertation, heterostructured micro-acoustic devices are explored that leverage the interactions between acoustic phonons and electrons to enable radio frequency (RF) signal amplification or attenuation. Thin films of piezoelectric and semiconductor material are tailored into a heterostructure that allows for a strong acoustoelectric (AE) effect due to the combination of high electromechanical coupling and high electron drift velocity in said films respectively. In such devices, the relative electron drift and acoustic velocities could determine whether the RF signal undergoes AE gain or loss, rendering the device non-reciprocal. This is a highly sought-after property for building isolators and circulators which …
Study Of Mos2/High-K Interface And Implementation Of Mos2 Based Memristor For Neuromorphic Computing Applications, Durjoy Dev
Electronic Theses and Dissertations, 2020-
The scientific world is witnessing an unprecedented triumph of artificial neural network (ANN)- a computing system inspired by the biological neural network. With the enthralling quest for Internet of Everything (IoE), it is expected to have an unparalleled dominance of ANN in our day-to-day life. In recent times, memristor has come as an emerging candidate to realize ANN through emulating biological synapse and neuron behavior. Molybdenum disulfide (MoS2), one well-known two-dimensional (2D) transition metal dichalcogenides (TMDCs), has drawn interest for high speed, flexible, low power electronic devices since it has a tunable bandgap, reasonable carrier mobility, high Young's modulus, and …
Design Of Miniaturized Antipodal Vivaldi Antennas And A Microwave Head Imaging System For The Detection Of Blood Clots In The Brain, Farhana Parveen
Design Of Miniaturized Antipodal Vivaldi Antennas And A Microwave Head Imaging System For The Detection Of Blood Clots In The Brain, Farhana Parveen
Electronic Theses and Dissertations, 2020-
Traditional brain imaging modalities, for example, MRI, CT scan, X-ray, etc. can provide precise and high-resolution images of the brain for diagnosing lesions, tumors or clots inside the brain. However, these modalities require bulky and expensive test setups accessible only at specialized diagnostic centers, and hence may not be suitable or affordable to many patients. Furthermore, the inherent health risks limit the usability of these modalities for frequent monitoring. Microwave imaging is deemed a promising alternative due to its being cost-effective, portable, non-ionizing, non-intrusive. Therefore, this work aims to design an effective microwave head imaging system for the detection of …
Development Of Rf-Mems Based Passive Wireless Respiratory Monitoring Systems, Sina Moradian
Development Of Rf-Mems Based Passive Wireless Respiratory Monitoring Systems, Sina Moradian
Electronic Theses and Dissertations, 2020-
This dissertation explores the application of high frequency, low loss, high quality factor thin-film piezoelectric MEMS resonators as passive wireless respiratory monitoring sensors. In this work we build on advances in RF MEMS technology and wearables to develop a respiratory monitoring system capable of measuring respiration without any on-board circuitry and battery First, a wireless MEMS-based respiration sensor that operates without a battery or any on-board circuitry is presented. The sensing system is made up two major components, the wireless sensor and a base transceiver and computational unit. The sensor is only made of up of two RF-MEMS resonators and …
Robust And Scalable Data Representation And Analysis Leveraging Isometric Transformations And Sparsity, Alireza Zaeemzadeh
Robust And Scalable Data Representation And Analysis Leveraging Isometric Transformations And Sparsity, Alireza Zaeemzadeh
Electronic Theses and Dissertations, 2020-
The main focus of this doctoral thesis is to study the problem of robust and scalable data representation and analysis. The success of any machine learning and signal processing framework relies on how the data is represented and analyzed. Thus, in this work, we focus on three closely related problems: (i) supervised representation learning, (ii) unsupervised representation learning, and (iii) fault tolerant data analysis. For the first task, we put forward new theoretical results on why a certain family of neural networks can become extremely deep and how we can improve this scalability property in a mathematically sound manner. We …
Novel Liquid Crystal Photonic Devices Enabled By Liquid Crystal Alignment Engineering, Ziqian He
Novel Liquid Crystal Photonic Devices Enabled By Liquid Crystal Alignment Engineering, Ziqian He
Electronic Theses and Dissertations, 2020-
Liquid crystals (LCs) are self-assembled soft materials composed of certain anisotropic molecules with orientational orders. Their widespread applications include information displays and photonic devices, such as spatial light modulators for laser beam steering and tunable-focus lens, where achieving desired LC alignment is pivotal. In general, LC alignment is influenced by several factors, including chemical bonding, dipolar interactions, van der Waals interactions, surface topographies, and steric factors. Here, we focus on three alignment techniques for aligning rod-like LC molecules and highlights the photonic devices enabled by these techniques: 1) Two-photon polymerization direct-laser writing-induced alignment, 2) Weigert effect-based reversible photoalignment, and 3) …
Development Of Quantitative Intensity-Based Single-Molecule Assays, Benjamin Croop
Development Of Quantitative Intensity-Based Single-Molecule Assays, Benjamin Croop
Electronic Theses and Dissertations, 2020-
Fluorescence microscopy has emerged as a popular and powerful tool within biology research, owing to its exceptional signal contrast, specificity, and the versatility of the various microscope designs. Fluorescence microscopy has been used to study samples across orders of magnitude in physical scale ranging from tissues to cells, down to single-molecules, and as such has led to breakthroughs and new knowledge in a wide variety of research areas. In particular, single-molecule techniques are somewhat unique in their ability to study biomolecules in their native state, which enables the visualization of short-lived interactions and rare events which can be highly relevant …
Directional Link Management Using In-Band Full-Duplex Free Space Optical Transceivers For Aerial Nodes, A F M Saniul Haq
Directional Link Management Using In-Band Full-Duplex Free Space Optical Transceivers For Aerial Nodes, A F M Saniul Haq
Electronic Theses and Dissertations, 2020-
Free-space optical (FSO) communication has become very popular for wireless applications to complement and, in some cases, replace legacy radio-frequency for advantages like unlicensed band, spatial reuse, and enhanced security. Even though FSO can achieve very high bit-rate (tens of Gbps), range limitation due to high attenuation and weather dependency has always restricted its practical implementation to indoor application like data centers and outdoor application like Project Loon. Building-to-building communication, smart cars, and airborne drones are potential futuristic wireless communication sectors for mobile ad-hoc FSO networking. Increasing social media usage demands high-speed mobile connectivity for applications like video call and …
Fabrication Of High-Frequency Piezoelectric Resonant Micro-Accelerometers Based On Capacitive Loading Effect, Ankesh Todi
Fabrication Of High-Frequency Piezoelectric Resonant Micro-Accelerometers Based On Capacitive Loading Effect, Ankesh Todi
Electronic Theses and Dissertations, 2020-
In this thesis, a high-frequency resonant accelerometer is presented. This novel sensor was designed to operate in 10's of MHz frequency range utilizing an out-of-plane capacitive mechanism for acceleration sensing. The sensor is comprised of a 2-port RF MEMS piezoelectric resonator, operating at 27MHz, and a Capacitive Mass-spring structure. One of the resonator ports is electrically connected to the variable capacitor in the mass-spring structure. The acceleration is measured utilizing a piezoelectric stiffening mechanism, where a change in the termination impedance of a piezoelectric resonant body would result in a shift in the resonance frequency of the resonator. The acceleration …
Ultraviolet Solar Blind Ga2o3-Based Photodetectors, Isa Hatipoglu
Ultraviolet Solar Blind Ga2o3-Based Photodetectors, Isa Hatipoglu
Electronic Theses and Dissertations, 2020-
Detection within the deep ultraviolet (DUV) region (˜200-280 nm) offers unique fundamental advantages to probe certain optical traces. Therefore, many applications have emerged including flame and missile detection, and non-line of sight and space-to-space communication. Ga2O3 has become a natural choice for DUV detection owing to its intrinsic ultra-wide optical bandgap (˜4.85 eV), extrinsic n-type dopability, and excellent chemical and physical stability. However, Ga2O3 has no viable p-type doping to date, and fabricated photodetectors show only partial coverage of the entire solar-blind region (˜200-245nm). Furthermore, there is a limited understanding of how various growth parameters for ß-Ga2O3 and its alloys …
Secure And Trustworthy Hardware And Machine Learning Systems For Internet Of Things, Shayan Taheri
Secure And Trustworthy Hardware And Machine Learning Systems For Internet Of Things, Shayan Taheri
Electronic Theses and Dissertations, 2020-
The advancements on the Internet have enabled connecting more devices into this technology every day. This great connectivity has led to the introduction of the internet of things (IoTs) that is a great bed for engagement of all new technologies for computing devices and systems. Nowadays, the IoT devices and systems have applications in many sensitive areas including military systems. These challenges target hardware and software elements of IoT devices and systems. Integration of hardware and software elements leads to hardware systems and software systems in the IoT platforms, respectively. A recent trend for the hardware systems is making them …
Representative-Based Big Data Processing In Communications And Machine Learning, Mohsen Joneidi
Representative-Based Big Data Processing In Communications And Machine Learning, Mohsen Joneidi
Electronic Theses and Dissertations, 2020-
The present doctoral dissertation focuses on representative-based processing proper for a big set of high-dimensional data. Compression and subset selection are considered as two main effective methods for representing a big set of data by a much smaller set of variables. Compressive sensing, matrix singular value decomposition, and tensor decomposition are employed as powerful mathematical tools to analyze the original data in terms of their representatives. Spectrum sensing is an important application of the developed theoretical analysis. In a cognitive radio network (CRN), primary users (PUs) coexist with secondary users (SUs). However, the secondary network aims to characterize PUs in …
Data-Driven Analysis For Integrated Transmission And Distribution Systems With High Penetration Of Distributed Energy Resources, Inalvis Alvarez-Fernandez
Data-Driven Analysis For Integrated Transmission And Distribution Systems With High Penetration Of Distributed Energy Resources, Inalvis Alvarez-Fernandez
Electronic Theses and Dissertations, 2020-
With the high penetration of inverter-based distributed energy resources (DERs), network situational awareness is a challenge for both transmission and distribution (T&D) system operators and planners. It is becoming increasingly important to equip transmission planners with the visibility of DER dynamic performance in distribution systems. Not having visibility of the disconnection of DERs with the occurrence of transmission events, could result in an erroneous view of the stability of bulk power system. The aggregated distributed energy resource (DER_A) model is able to model the aggregated dynamic response of inverter-based DERs in distribution circuits. The parameterization of DER_A model requires extensive …
Switchable Slot-Ring Antennas For Customizable Phased Array Applications, Junyi Huang
Switchable Slot-Ring Antennas For Customizable Phased Array Applications, Junyi Huang
Electronic Theses and Dissertations, 2020-
Switchable-band shared-aperture slot-ring antennas with wide bandwidth and polarization agility are explored in this article for phased array applications. A common antenna aperture can be reconfigured between S-band and C-band arrays using PIN diode switches. A new arraying technique is implemented herein to achieve reconfigurable polarization states. Within each array element, only one port is needed to realize reconfigurable polarization states by providing appropriate phases to each port. Compared with the state of the art, this arrangement can reduce the number of ports of a large phased array by half, therefore significantly reduce the cost and complexity, eliminate the isolation …
Parameter Calibration And Optimization In Smart Grid For Synchronous Generators And Converters, Seyyed Rashid Khazeiynasab
Parameter Calibration And Optimization In Smart Grid For Synchronous Generators And Converters, Seyyed Rashid Khazeiynasab
Electronic Theses and Dissertations, 2020-
In power systems, monitoring, protection, and control are usually model based; an accurate dynamic model for either synchronous generators or power electronic converters is essential. Besides, renewable energies, smart loads, energy storage, and new market behavior add new sources of uncertainty to power systems. Therefore, planning in real-time and developing high-quality models is crucial to adapt to uncertainties. In this thesis, we propose a framework for validating and calibrating power system models using novel methods. At the first step, we developed the nonlinear sensitivity-based method to find the critical parameters. Then, we propose an Approximate Bayesian Computation (ABC) based method …
Distributed Service Restoration In Active Distribution Networks, Nejad Reza Roofegari
Distributed Service Restoration In Active Distribution Networks, Nejad Reza Roofegari
Electronic Theses and Dissertations, 2020-
Despite tremendous efforts on increasing power system reliability, outages and blackouts are inevitable. These losses can be greatly reduced by fast and reliable restoration mechanisms. Largescale distribution networks and increasing penetration of distributed energy resources (DERs) make restoration one of the most challenging problems in power systems. The prevailing centralized restoration scheme is costly, limited by information privacy of entities, unreliable due to dependence on central units, and might suffer from single-point failures. In this dissertation, a fully distributed restoration framework based on the alternating direction method of multipliers (ADMM) is proposed to address these challenges. Accordingly, the restoration problem …
Multi-Functional Fluorescence Microscopy Via Psf Engineering For High-Throughput Super-Resolution Imaging, Jinhan Ren
Multi-Functional Fluorescence Microscopy Via Psf Engineering For High-Throughput Super-Resolution Imaging, Jinhan Ren
Electronic Theses and Dissertations, 2020-
Image-based single cell analysis is essential to study gene expression levels and subcellular functions with preserving the native spatial locations of biomolecules. However, its low throughput has prevented its wide use to fundamental biology and biomedical applications which require large cellular populations in a rapid and efficient fashion. Here, we report a 2.5D microcopy (2.5DM) that significantly improves the image acquisition rate while maintaining high-resolution and single molecule sensitivity. Unlike serial z-scanning in conventional approaches, volumetric information is simultaneously projected onto a 2D image plane in a single shot by engineering the fluorescence light using a novel phase pattern. The …
Reliability And Failure Analysis Of Gan-On-Si Power Devices, Wen Yang
Reliability And Failure Analysis Of Gan-On-Si Power Devices, Wen Yang
Electronic Theses and Dissertations, 2020-
Wide bandgap power semiconductor devices, especially Gallium Nitride (GaN) high electron mobility transistors (HEMTs), have gained a lot of attention for high power applications due to their low on-resistance and high switching speed compared to their silicon counterparts. However, the reliability and failure issues related to dynamic performance, gate reliability, and electrostatic discharge have limited the wide applications of GaN power devices. This dissertation presents a systematic study of reliability and failure analysis of GaN-on-Si power devices. Firstly, the correlation between the physical trap mechanisms and the dynamic on-resistance (Ron) degradation has been investigated using a multi-frequency C-V measurement during …
Performance Enhancement Of Rf/Microwave Devices Using Filter Synthesis Techniques, Ricardo Lovato
Performance Enhancement Of Rf/Microwave Devices Using Filter Synthesis Techniques, Ricardo Lovato
Electronic Theses and Dissertations, 2020-
This dissertation shows that filter synthesis techniques can be used to design and enhance the performance of several discrete components of the RF front-end. Throughout this work, a block diagram of a typical receiver is used to illustrate each component separately. Four main areas are covered: (1) filter/antenna integration, (2) frequency-tunable filter/antenna integration with control of the bandwidth characteristics, (3) antenna arrays designed based on integrated cavity resonators, and (4) novel low-loss phase shifters using band-pass and band-stop filters. The filter/antenna designed using two cavity resonators with a slot antenna in the second cavity. The slot antenna excites two modes …
High-Density Neurochemical Microelectrode Array To Monitor Neurotransmitter Secretion, Kevin White
High-Density Neurochemical Microelectrode Array To Monitor Neurotransmitter Secretion, Kevin White
Electronic Theses and Dissertations, 2020-
Neuronal exocytosis facilitates the propagation of information through the nervous system pertaining to bodily function, memory, and emotions. Using amperometry, an electrochemical technique that directly detects electroactive molecules, the sub-millisecond dynamics of exocytosis are revealed and the modulation of neurotransmitter secretion due to neurodegenerative diseases or pharmacological treatments can be studied. The method of detection using amperometry is the exchange of electrons due to a redox reaction at an electrochemically sensitive electrode. As electroactive molecules, such as dopamine, undergo oxidation, electrons are released from the molecule to the electrode and an oxidation current is generated and recorded. Despite the significance …
Reliable And Efficient Cognitive Radio Communications Using Directional Antennas, Hassan Yazdani
Reliable And Efficient Cognitive Radio Communications Using Directional Antennas, Hassan Yazdani
Electronic Theses and Dissertations, 2020-
Cognitive Radio (CR) is a promising solution that enhances spectrum utilization by allowing an unlicensed or Secondary User (SU) to access licensed bands in a such way that its imposed interference on a license holder Primary User (PU) is limited, and hence fills the spectrum holes in time and/or frequency domains. Resource allocation, which involves scheduling of available time and transmit power, represents a crucial problem for the performance evaluation of CR systems. In this dissertation, we study the spectral efficiency maximization problem in an opportunistic CR system. Specifically, in the first part of the dissertation, we consider an opportunistic …
Periodicity Estimation Using Representations In Nested Periodic Dictionaries With Applications In Neural Engineering, Pouria Saidi
Periodicity Estimation Using Representations In Nested Periodic Dictionaries With Applications In Neural Engineering, Pouria Saidi
Electronic Theses and Dissertations, 2020-
In this dissertation, we investigate periodicity estimation with nested periodic dictionaries (NPDs), a newly introduced family of matrices that can capture periodicity in the data. We address two main problems. First, we study the detection of periodic signals using their representations in NPDs. To this end, the detection problem is posed as a composite hypothesis testing problem, where the signals are assumed to admit sparse representations in a Ramanujan Periodicity Transform (RPT) dictionary as an instance of NPDs. For the binary case, we develop a generalized likelihood ratio detector and obtain exact distributions of the test statistics in terms of …
Low-Profile Wireless Passive Temperature Sensors, Ectis Velazquez
Low-Profile Wireless Passive Temperature Sensors, Ectis Velazquez
Electronic Theses and Dissertations, 2020-
This thesis explores design challenges and promising solutions for temperature sensors for high temperature environments such as combustion turbines. To survive this high temperature environment of over 1000 °C the sensors are required to be robust in their electrical and mechanical properties. Wire connections for these high temperature environments are a complex problem due to the physical limitations of most materials at those high temperatures. In this thesis, robust ceramic sensors based on microwave resonators are demonstrated for high temperature environments, with some studies into optimizing the techniques used to measure them, as well as the distance at which their …
The Effect Of Annealing Temperatures And Inert/Reactive Gasses On Optical Properties Of Cu2o And Cuo Thin Films, Radu Bunea
Electronic Theses and Dissertations, 2020-
The Cu2O and CuO thin films were synthesized by using RF sputtering technique. Comparisons were made with films created by deposition at room temperature followed by thermal annealing between 1000C and 4000C and using different gases, oxygen (O2) (oxidizing and reactive gas) and nitrogen (N2) (inert gas), besides air. The thickness of the thin films were kept constant, around 2000 Å (Angstrom). In addition, the RF power and pressure deposition were kept constant, as well. The thin films were evaluated for a range of wavelengths between 200 nm and 400 nm (Ultra Violet spectrum), …
Atomically Thin Platinum-Based Dichalcogenide Materials For Multifunctional Photo-Sensitive Applications, Mashiyat Sumaiya Shawkat
Atomically Thin Platinum-Based Dichalcogenide Materials For Multifunctional Photo-Sensitive Applications, Mashiyat Sumaiya Shawkat
Electronic Theses and Dissertations, 2020-
Two-dimensional (2D) transition metal dichalcogenides (TMDs) are a distinct class of atomically thin materials assembled by weak van der Waals bonding. They exhibit 2D layer number-dependent bandgap tunability promising exciting applications in electronics and optoelectronics. Among them, there is a surge of interest in Platinum-based dichalcogenides (e.g., PtSe2 and PtTe2). 2D PtSe2 has a theoretically predicted carrier mobility of > 1000 cm2/(Vs), at room temperature, which is higher than that of most 2D TMDs. Additionally, 2D PtSe2 exhibits a semiconducting to metallic transition with an increasing number of layers. 2D PtTe2 is highly metallic in its few- layer form and exhibits …
Characterization Of Hydrogenated Boron Carbide And Boron Carbon Nitride Thin Films And Applications, Shraddha Dhanraj Nehate
Characterization Of Hydrogenated Boron Carbide And Boron Carbon Nitride Thin Films And Applications, Shraddha Dhanraj Nehate
Electronic Theses and Dissertations, 2020-
Dimension scaling has been the driving force for improved performance of semiconductor integrated circuits (ICs) for the past few decades. While the semiconductor industry continues to achieve returns on Moore's law, the resistance-capacitance (RC) delay remains a critical bottleneck towards further performance improvement. To support advanced computing performance, the development and integration of new low dielectric (low-k) materials to reduce the capacitance of interconnects are crucial. Apart from the low dielectric constant value, one of the other vital parameters to replace the current dielectric material is mechanical stability. Materials in the boron, carbon, and nitrogen ternary triangle have emerged promising …
Mechanically Reconfigurable Materials And Devices Based On Two-Dimensional Transition Metal Dichalcogenide Layers, Emmanuel Okogbue
Mechanically Reconfigurable Materials And Devices Based On Two-Dimensional Transition Metal Dichalcogenide Layers, Emmanuel Okogbue
Electronic Theses and Dissertations, 2020-
The recent advances in electronic technologies are geared towards a combination of continued miniaturization in device components and their integration onto unconventional platforms. These efforts are aimed towards achieving electronic devices with various form factors and novel functionalities which are unattainable from traditional devices. Among these envisioned 'futuristic' technologies, electronic devices which are mechanically reconfigurable and operable under harsh operational conditions in the form of stretching, twisting and folding offer tremendous amount of unparalleled opportunities. This dissertation studies two-dimensional (2D) transition metal dichalcogenide (TMDs), a distinct class of materials with peculiar optical, electrical and mechanical properties for mechanically reconfigurable electronics. …