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Lei, FeiranInjection Locked Synchronous Oscillators (SOs) and Reference Injected Phase-Locke Loops (PLL-RIs)
Doctor of Philosophy, The Ohio State University, 2017, Electrical and Computer Engineering
Synchronization plays an important and fundamental role as the timing basis in digital, analog, and RF integrated circuits (ICs), where Phase-Locked Loops (PLLs) find their versatile applications. The noise sources in a traditional PLL are mainly divided into two groups: noise before the low-pass loop filter such as the noise in the reference signal, Frequency Divider (FD), Phase Frequency Detector/Charge Pump (PFD/CP); and noise after the filter such as the Voltage Controlled Oscillator (VCO) noise and the loop filter noise. The output phase noise of the PLL is the combined contribution from these two equally important in-band and out-band noise sources. This research studies the effect of the synchronization in the PLL on the decoupling of the 3dB bandwidths for different noise sources to achieve an optimum phase noise and improved locking behavior with an attenuated reference signal injection (RI) into a ring-type delay-line Voltage Controlled Synchronous Oscillator (VCSO). This dissertation begins with the development of a generalized phase model for both LC-type and ring-type VCSOs. Next, the relationship between the device baseband noise (flicker and thermal noise) and a ring-type oscillator's phase noise is derived. In addition, noise shaping functions are introduced to describe signal injection into the VCSO to achieve suppression of the oscillator in-band phase noise. Then, the transient and steady-state behavior of a Charge-Pump PLL-RI are explained with nonlinear differential equations and the phase-plane method. The nonlinear phase equation is linearized for the small-signal condition and the s-domain noise transfer functions as well as noise bandwidths are derived for different noise sources in the major components of the PLL-RI. The effect of the loop parameters and the injection strength on the output phase noise, loop settling time, and lock in range is analyzed. The analysis is verified by the SPICE simulation and experimental results from a Charge-Pump PLL-RI using a 1GHz VCSO in GlobalFoundries 130nm standard CMOS technology. The designed VCSO occupies a core area of 0.005 mm$^2$, and operates from 0.5GHz to 1.7GHz. The PLL-RI, for first-harmonic locking applications, has a core area of 0.02 mm$^2$ and consumes 2.6mW power. When a 30dB attenuation is applied, phase noise at 1MHz and 10MHz offset are reduced from -118.8dBc/Hz (PLL) to -121.9dBc/Hz (PLL-RI), and -102.3dBc/Hz (PLL) to -128.3dBc/Hz (PLL-RI), respectively, with an integrated RMS jitter from 10KHz to 30MHz of 1.55ps. Finally, another application of the PLL-RI as an integer-N frequency synthesizer is studied and tested. The PLL-RI based frequency synthesizer with the ring-type VCSO achieves comparable noise performance with LC type PLLs, but uses a much smaller chip area and features lower power consumption. To summarize, this dissertation has throughly evaluated an oscillator and a PLL under small signal injection. Compared with the traditional PLL, the all-CMOS PLL-RI offers faster settling time, wider lock in range, and ability to decouple 3dB bandwidths for different noise sources to achieve an optimum noise performance. The applications of PLL-RIs can be extended to analog, digital, and RF systems for different timing schemes.

Committee:

Marvin White (Advisor); Waleed Khalil (Committee Member); Steven Bibyk (Committee Member)

Subjects:

Electrical Engineering

Keywords:

CMOS ICs; PLLs, Frequency Synthesizers, reference injection locking; phase noise suppression; jitter; low-frequency 1-f noise; thermal noise; RF measurements; device modeling parameter extraction; low power; adaptive tracking range; design and fabrication

Jamalzadeh, RezaMicrogrid Optimal Power Flow Based On Generalized Benders Decomposition
Doctor of Philosophy, Case Western Reserve University, 2018, EECS - System and Control Engineering
The future distribution system is envisioned to be a network of distributed energy resources (DER), being able to operate in both the grid connected and islanded modes. In essence, the future electrical distribution systems will operate as medium-voltage (MV) microgrids. This dissertation presents a study of the optimal power flow (OPF) based on generalized benders decomposition (GBD) for optimally scheduling DERs and managing voltage regulation device operations to enable the economic and secure operations of the future MV distribution systems. Key model considerations include multi-phase unbalanced distribution system network, conservation voltage reduction (CVR), and multi-interval energy scheduling. Further, the optimal operating decisions are studied when the MV microgrid is in different operational modes, such as the 1) grid-connected mode, 2) islanded mode, and 3) grid-connected to islanded mode transition. Excellent algorithm performance has been achieved on the IEEE test feeder models. The use of an external engine for solving the unbalanced power flow and obtaining the sensitivities for the decomposed sub-problems allows the OPF to handle scaled-up models with the increased number of decision variables, constraints, and network buses. To support solution of large-scale problems, parallel computational strategies are recommended in order to achieve solution performance required by operations. Among the output of the GBD-based OPF, the primal solution provides optimal operation set point decisions while the dual solution provides system marginal-cost based energy prices such as the locational marginal prices (LMP) for single-phase nodes. These important OPF outcomes can facilitate the economic electricity market design in the distribution system involving both DERs and end-use demands. In this dissertation, a new method based on the GBD-based OPF has also been proposed using the unbalanced power system model linearized around the near-optimal operational state to calculate LMPs for single-phase buses and support the economic market design of the distribution system. Also in this dissertation, the approximation of nodal voltage sensitivities is studied based on observations made about the radial distribution system. As a result, voltage sensitivities can be efficiently computed for all network nodes simply based on the power flow solution and topology searches. The results are validated on the IEEE test feeder models using the perturbation analysis. The proposed method can be applied to large unbalanced radial distribution systems for supporting distribution system planning and operation.

Committee:

Mingguo Hong, PhD (Advisor); Kenneth Loparo, PhD (Committee Member); Vira Chankong, PhD (Committee Member); Evren Gurkan-Cavusoglu, PhD (Committee Member)

Subjects:

Electrical Engineering; Energy

Keywords:

Active distribution system operation; conservation voltage reduction; distributed energy resources; generalized benders decomposition; locational marginal price; microgrid; optimal power flow; unbalanced distribution system; voltage sensitivity

Trombley, MichaelDesign of a Programmable Four-Preset Guitar Pedal
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
Many companies in the music industry offer programmable preset guitar pedals. Presets allow musicians to save time and focus on their act by recalling predetermined settings during a performance. A majority of the companies in the music industry offer up to hundreds of presets, but realistically the substantial amount of presets may have a negative effect on the musician’s performance due to time constraints. The main contribution of this thesis is to address the musician by reducing the amount of presets offered in a guitar pedal design. Combining two systems, a digital control and audio processing circuit, will produce a programmable four-preset guitar pedal. Cost and size are design constraints that will also be taken into consideration. The techniques observed in this thesis will benefit the music industry because they can be adapted into other guitar pedal designs. This thesis closes with an evaluation of the final design, feedback from musicians in the community, and suggestions for future improvements.

Committee:

Marian Kazimierczuk, Ph.D. (Advisor); Joe Tritschler, Ph.D. (Committee Member); Yan Zhuang, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Guitar; Music; Microcontroller; Programming; Audio; DSP; Digital Signal Processing; Audio Signal Processing;

Dalwadi, NeelNull Values and Null Vectors of Matrix Pencils and their Applications in Linear System Theory
Master of Science in Engineering (MSEgr), Wright State University, 2017, Electrical Engineering
Considerable literature exists in linear algebra to solve the generalized eigenvalue, eigenvector problem (F - λ G)v = 0 where F, G ∈ ℜ(s × s), are square matrices. However, a number of applications lend themselves to the case where F, G ∈ ℜ(s × t), and st. The existing methods cannot be used for such non-square cases. This research explores structural decomposition of a matrix pencil (F - λ G), s ≠ t to compute finite values of λ for which rank(F - λ G) < min(s,t). Moreover, from the decomposition of the matrix pencil, information about the order of λ at infinity, the Kronecker row and column indices of a matrix pencil can also be extracted. Equally important is the computation of non-zero vectors w ∈ ℜ(1 × s) and v ∈ ℜ(t × 1) corresponding to each finite value of λ, such that w(F - λ G) = 0 and (F - λ G)v = 0. Algorithms are developed for the computation of λ, w, and v using numerically efficient techniques. Proposed algorithms are applied to problems encountered in system theory and illustrated by means of numerical examples.

Committee:

Pradeep Misra, Ph.D. (Advisor); Xiaodong Zhang, Ph.D. (Committee Member); Luther Palmer III, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Mathematics

Keywords:

Null Values; Null Vectors; Eigenvalue; Eigenvector; Generalized Eigenvector; Non square; Matrix Pencil; Non square Matrix Pencil; values; vectors; Kronecker Canonical Form; Indices

Khalili, MohsenDistributed Adaptive Fault-Tolerant Control of Nonlinear Uncertain Multi-Agent Systems
Doctor of Philosophy (PhD), Wright State University, 2017, Engineering PhD
The research on distributed multi-agent systems has received increasing attention due to its broad applications in numerous areas, such as unmanned ground and aerial vehicles, smart grid, sensor networks, etc. Since such distributed multi-agent systems need to operate reliably at all time, despite the possible occurrence of faulty behaviors in some agents, the development of fault-tolerant control schemes is a crucial step in achieving reliable and safe operations. The objective of this research is to develop a distributed adaptive fault-tolerant control (FTC) scheme for nonlinear uncertain multi-agent systems under intercommunication graphs with asymmetric weights. Under suitable assumptions, the closed-loop system's stability and leader-follower cooperative tracking properties are rigorously established. First, a distributed adaptive fault-tolerant control method for nonlinear uncertain first-order multi-agent systems is developed. Second, this distributed FTC method is extended to nonlinear uncertain second-order multi-agent systems. Next, adaptive-approximation-based FTC algorithms are developed for two cases of high-order multi-agent systems, i.e., with full-state measurement and with only limited output measurement, respectively. Finally, the distributed adaptive fault-tolerant formation tracking algorithms for first-order multi-agent systems are implemented and demonstrated using Wright State's real-time indoor autonomous robots test environment. The experimental formation tracking results illustrate the effectiveness of the proposed methods.

Committee:

Xiaodong Zhang, Ph.D. (Advisor); Kuldip Rattan, Ph.D. (Committee Member); Pradeep Misra, Ph.D. (Committee Member); Yongcan Cao, Ph.D. (Committee Member); Raul Ordonez, Ph.D. (Committee Member); Mark Mears, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Engineering

Keywords:

Fault-Tolerant Control; Adaptive Control; Multi-Agent Systems; Nonlinear Uncertain Systems; Formation Control; Learning Systems; Cooperative Tracking; Leader-Follower Consensus; Asymmetric Communication Graphs; Fault Diagnosis; Mobile Robots

Imbulgoda Liyangahawatte, Gihan Janith MendisHardware Implementation and Applications of Deep Belief Networks
Master of Science in Engineering, University of Akron, 2016, Electrical Engineering
Deep learning is a subset of machine learning that contributes widely to the contemporary success of artificial intelligence. The essential idea of deep learning is to process complex data by abstracting hierarchical features via deep neural network structure. As one type of deep learning technique, deep belief network (DBN) has been widely used in various application fields. This thesis proposes an approximation based hardware realization of DBNs that requires low hardware complexity. This thesis also explores a set of novel applications of the DBN-based classifier that will benefit from a fast implementation of DBN. In my work, I have explored the application of DBN in the fields of automatic modulation classification method for cognitive radio, Doppler radar sensor for detection and classification of micro unmanned aerial systems, cyber security applications to detect false data injection (FDI) attacks and localize flooding attacks, and applications in social networking for prediction of link properties. The work in this thesis paves the way for further investigation and realization of deep learning techniques to address critical issues in various novel application fields.

Committee:

Jin Wei (Advisor); Arjuna Madanayaka (Committee Co-Chair); Subramaniya Hariharan (Committee Member)

Subjects:

Artificial Intelligence; Computer Engineering; Electrical Engineering; Engineering; Experiments; Information Technology

Keywords:

deep belief networks; multiplierless digital architecture; Xilinx FPGA implementations; low-complexity; applications of deep belief networks; spectral correlation function; modulation classification; drone detection; doppler radar; cyber security

Pyles, David T.Effects of the Kinematic Model on Forward-Model Based Spotlight SAR ECM
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
Spotlight synthetic aperture radar (SAR) provides a high-resolution remote image formation capability for airborne platforms. SAR image formation processes exploit the amplitude, time, and frequency shifts that occur in the transmitted waveform due to electromagnetic propagation and scattering. These shifts are predictable through the SAR forward model which is dependent on the waveform parameters and emitter flight path. The approach to develop an electronic countermeasure (ECM) system that is founded on the SAR forward model implies that the ECM system should alter the radar’s waveform in a manner that produces the same amplitude, time, and frequency shifts that a real scatterer would produce at a desired location. A collection of such scatterers would be capable of forming a larger collective energy distribution in the final image. However, since the forward model is dependent on the radar platform’s kinematic model, the jamming energy distribution created from a forward-model based ECM system will inherently have some level of sensitivity to kinematic error. This thesis discusses a forward-model based ECM modulation scheme and provides an assessment of its sensitivity through Monte Carlo simulations and an entropy-based image similarity distance.

Committee:

Michael A. Saville, Ph.D. (Committee Chair); Brian Rigling, Ph.D. (Committee Member); Steve Gorman, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

electrical engineering; spotlight synthetic aperture radar; SAR

Rafique, SubrinaGrowth, Characterization and Device Demonstration of Ultra-Wide Bandgap ß-Ga2O3 by Low Pressure Chemical Vapor Deposition
Doctor of Philosophy, Case Western Reserve University, EECS - Electrical Engineering

High power semiconductor device technology has significant impact on the society as they can directly contribute to worldwide energy conservation. The main market segments for high-power, high-frequency semiconductor devices are industrial motors, hybrid and electric vehicles, RF and power supply, wireless infrastructure and broadcast and communication satellites. Si-based technology has been serving the power electronics market till today. However, Si based power devices are approaching their theoretical performance limits from the viewpoint of material properties. Wide bandgap (WBG) semiconductors featured with higher breakdown electric field have tremendous advantages over existing Si based technology. They can operate at higher voltages, temperatures and switching frequencies with greater efficiencies resulting in less loss. They also enable significantly reduced system level volumes due to decreased cooling requirements and smaller passive components contributing to overall lower system costs. Once widely used, wide bandgap semiconductor based power electronics technologies can save over 25% of the worldwide annual energy consumption.

Ultra-wide bandgap (UWBG) semiconductor material gallium oxide (Ga2O3) with a room temperature bandgap of ~4.9 eV, much higher than GaN (Eg~3.4 eV) and SiC (Eg~3.2 eV), is a promising candidate for next generation power devices and deep ultraviolet (DUV) photodetectors (PDs). It possesses excellent material properties and outstanding chemical and thermal stability at elevated temperatures. Most attractively, Ga2O3 substrate can be produced by low cost and scalable melting based methods. In this dissertation, a new epitaxial method based on low pressure chemical vapor deposition (LPCVD) is developed and demonstrated for the first time to grow high quality Ga2O3 based thin films and nanomaterials with fast growth rate and controllable doping. For the LPCVD growth of Ga2O3, argon (Ar) is employed as carrier gas. High purity gallium pellets (Alfa Aesar, 99.99999%) are used as the group III precursor. Oxygen (O2) and Silicon Tetrachloride (SiCl4) are the group VI precursor and n-dopant source, respectively. Proof of concept prototypes of ß-Ga2O3 thin films based PDs and Schottky barrier diode (SBD) have been demonstrated using LPCVD grown Ga2O3 thin films. The maximum room temperature electron Hall mobility achieved for LPCVD heteroepitaxial Ga2O3 thin films is 106.6 cm2/V·s with an n-type carrier concentration of 4.83x1017 cm-3. The room temperature carrier concentrations achieved so far for the (010) and (001) LPCVD homoepitaxial thin films are ~1.4x1018 cm-3 and ~6.6x1017 cm-3 with mobilities of ~72 cm2/V. s and ~42 cm2/V. s respectively. Advancement of LPCVD growth of high quality ß-Ga2O3 will open up new opportunities for high performance power electronic and optoelectronic devices.

Committee:

Hongping Zhao (Advisor)

Subjects:

Electrical Engineering

Prasad, Anurag ShivamMAKING MILLIMETER WAVE COMMUNICATION POSSIBLE FOR NON-LINE-OF-SIGHT SCENARIOS: 5G
Master of Science, Miami University, 2017, Computational Science and Engineering
This thesis, provides for an enhanced version of the 5G Channel Simulator, NYUSIM, developed by NYU Wireless Lab for Millimeter Wave outdoor communications at New York University. This research is performed in the physical layer for Non-Line-of-Sight scenarios. Our goal is to increase the received signal power and establish a viable transmission link, reducing the degrading effects of multipath and atmospheric noise. To achieve this goal, a search algorithm is implemented to find the main spatial energy lobe with maximum power concentration and separate it from other spatial lobes that mostly contain noise. This will act as a reference point in order to perform adaptive beamforming needed for increasing the total received signal power and noise reduction.

Committee:

Donald Ucci (Advisor); Dmitriy Garmatyuk (Committee Member); Qihou Zhou (Committee Member)

Subjects:

Electrical Engineering; Engineering

Keywords:

5G;mmWaves;NYUSIM;Search Algorithm;Phased Array Antenna;Adaptive Beamforming

Johnson-Eusebio, Alejandro60 GHz 4-Bit Phase Shifter Design with VO2 Switches
Master of Science, The Ohio State University, 2018, Electrical and Computer Engineering
We present, for the first time, the design of a low-loss, 4-bit broadband switched-line phase shifter using vanadium dioxide (VO2) switches. The low-loss phase shifter exhibits average phase shift of 314 ° per dB of insertion loss and operates from 40 to 80 GHz. The dimensions of the 4-bit phase shifter is 0.75×1.35 mm2. This relatively small footprint, together with low losses, enables integration of the phase shifter with hybrid or passive electronically scanned arrays. Through full-wave simulation, the return loss was found to be better than 10 dB in all 16 states. Similarly, the minimum and maximum figure of merit for the phase shifter at 60 GHz were found to be 216 °/dB and 520 °/dB, respectively. Comparison of the simulated results for the designed phase shifter to experimental results reported in the literature, predicts that significant improvements can be expected from proposed phase shifters realized with VO2 switches.

Committee:

Nima Ghalichechian (Advisor); Patrick Roblin (Committee Member)

Subjects:

Electrical Engineering

Keywords:

mmW, vanadium dioxide, VO2, phase shifter, TTD

Wang, KaiHIGH PERFORMANCE SOLUTION-PROCESSED PEROVSKITE HYBRID SOLAR CELLS THROUGH DEVICE ENGINEERING AND NOVEL
Doctor of Philosophy, University of Akron, 2017, Polymer Engineering
ABSTRACT Efficiently and economically harnessing the solar energy via solar cell devices is one of promising solutions to address the global energy crisis. This thesis mainly focuses on a novel family of photoactive layer materials, namely organic-inorganic lead halide perovskite hybrids, and their corresponding solar cell devices, due to their potential for achieving outstanding power conversion efficiency and low-cost processibility. Specifically, the main research themes of this thesis are to achieve high performance perovskite hybrid solar cells through optimizing device structures, developing novel functional perovskite materials, and elucidating the underlying physics and mechanisms for guiding us to construct high performance solution-processed perovskite hybrid solar cells. This dissertation contains four parts and 10 chapters. In PART I, a broaden overview on both solar cell device and material is given, which specifically reviews the importance of solar energy and solar cells, comparison between previous-generation solar cells and perovskite hybrid solar cells, history of perovskite hybrid materials for solar cell application in Chapter 1 and describes the theoretical background of solar cell devices and material used for fabrication of solar cells in Chapter 2. PART II mainly includes the detailed projects on solar cell device engineering. Firstly, in Chapter 3, we employ a highly electrical conductive, polyethylene oxide (PEO)-doped poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as the hole extraction layer (HEL) for the planar heterojunction (PHJ) perovskite hybrid solar cells (pero-HSCs). The dramatically enhanced electrical conductivity of the PEO-doped PEDOT:PSS HEL provides an efficient pathway for the hole extraction, transport, and collection from the perovskite active layer to the anode. As a result, a significantly enhanced short-circuit current (JSC) of 23.42 mA cm-2, a slightly enlarged open-circuit voltage (VOC) of 0.88 V, an enhanced FF of 80.10% and a correspondingly dramatically enhanced power conversion efficiency (PCE) of 16.52%, which is a ~45% enhancement as compared with that from the PHJ pero-HSCs incorporated with the pristine PEDOT:PSS HEL, are observed. In Chapter 4, we utilize a solution-processed ultrathin layer of an ionomer, 4-lithium styrenesulfonic acid/styrene copolymer (LiSPS), to re-engineer the interface of methylammonium lead iodide (CH3NH3PbI3) in PHJ pero-HSCs. The ionomer can sufficiently modify the rough surface of the perovskite and optimize the charge extraction efficiency between perovskite photoactive layer and the charge transport layer. As a result, PHJ pero-HSCs with an increased photocurrent density of 20.90 mA cm-2, an enlarged ¿ll factor of 77.80%, a corresponding enhanced power conversion ef¿ciency of 13.83%, high reproducibility, and low photo-current hysteresis, are achieved. In Chapter 5, because one major limitation to increasing the efficiency of pero-HSCs is the fact that the diffusion length of the electrons is shorter than that of the holes, to facilitate the electron extraction efficiency in pero-HSCs and to make this efficiency comparable with that of the holes, we fabricated BHJ pero-HSCs by mixing perovskite materials with water-/alcohol soluble fullerene derivatives. The observed enhanced JSC and enlarged FFs were a result of the balance in the charge carrier extraction efficiency and the enlarged interfacial area between the perovskite materials and the fullerene derivatives. Significantly improved power conversion efficiencies were obtained for these BHJ pero-HSCs. A greater than 22% increase in power conversion efficiency was observed for the BHJ pero-HSCs compared with planar heterojunction pero-HSCs. A remarkable 86.7% FF, the highest reported value for pero-HSCs, was observed for the BHJ pero-HSCs. Our strategy of using a BHJ structure in pero-HSCs offers an efficient and simple way to further increase the performance of these devices. PART III mainly discusses the detailed projects on novel perovskite materials development. To fabricate homogeneous and high-quality perovskite thin ¿lms via low-temperature solution processing is always a challenge to realizing high-ef¿ciency pero-HSCs, in Chapter 6, we firstly report a development of an approach to realize smooth surface morphology of CH3NH3PbI3 perovskite thin ¿lms via using strong-polar ethanol solution rather than less-polar isopropanol solution, which was previously used as the solvent for preparing perovskite thin ¿lms. In comparison with the pero-HSCs processed from isopropanol solution, more than 40% enhanced ef¿ciency is observed from pero-HSCs processed from ethanol solution. The enhanced ef¿ciency is attributed to a homogeneous high-quality perovskite thin ¿lm with dramatically low root-mean-square roughness and completely conversion of lead (II) iodide (PbI2) to CH3NH3PbI3. In Chapter 7, we report the development and investigation of novel CH3NH3PbI3: x Nd3+(where x = 0, 0.1, 0.5, 1.0, and 5.0 mol%) perovskite hybrid materials, where Pb2+ is partially substituted by an inequivalent rare-earth metal cation, neodymium (Nd3+), which was never reported in previous studies. By conducting the charge carrier mobility measurements and film morphology studies, it is found that solution-processed CH3NH3PbI3: x Nd3+ thin films exhibit significantly improved and more balanced charge carrier mobilities, and superior film quality with dramatically reduced trap-states and pin-holes, as compared with pristine CH3NH3PbI3 thin film. As a result, a descent power conversion efficiency of 20.56% for solar cells and a superior photodetectivity of ~ 1014 cm Hz1/2 W-1 from 375 nm to 800 nm at room temperature for photodetector, are observed from solution-processed perovskite photovoltaics by novel CH3NH3PbI3: x Nd3+ thin films. All these results demonstrate that our method provides a simple and facial way to boost the device performance of perovskite photovoltaics. In Chapter 8, we report the utilization of polyethylene oxide additives to anchoring the ions in the perovskite lattice to suppress the formation of point defect or the migration of ions/vacancy, for simultaneously enhancing device efficiency, minimizing photocurrent hysteresis and enhancing device stability. Consequently, efficient solar cell devices with power conversion efficiency of 19.01% with extremely low hysteresis index of 0.001 and long-term device shelf half-life time of 504 hrs (without encapsulation, stored in 50% humidity air) have been achieved. Chemical, structural and morphological analysis show that the PEO additive acts as a crosslink between neighboring perovskite crystal domains via the strong hydrogen bonding of `-OH…I-’ and `O…H-NH2CH3+’ to the perovskite. In PART IV, a brief summerization on our works in terms of both device and material engineering is presented in Chapter 9, that is, for optimizing the device configuration as well as address critical issues in previously wide-applied hybrid perovskite thin films, we mainly developed novel ideas on: (i) modifying anode buffer layer for efficient hole extraction; (ii) modifying the interfacial electrical coherence on the i-n junction; (iii) developing a bulk heterojunction concept for efficient charge extraction; for novel materials part, we also focused on three major parts: (i) optimizing the thin film quality of perovskite; (ii) tuning the crystal lattice structure by inequivalent metal doping; (iii) anchoring the ion within the perovskite lattice for reducing hysteresis and improving device stability. Finally, an outlook is given in the Chapter 10 for guiding our future work.

Committee:

Xiong Gong (Advisor); Matthew Becker (Committee Member); Alamgir Karim (Committee Member); Nicole Zacharia (Committee Chair); Jie Zheng (Committee Member)

Subjects:

Electrical Engineering; Energy; Nanoscience; Physics; Polymers

Keywords:

Energy Conversion; Photovoltaics; Lead Halide Perovskite; High Performance; Device Physics; Material Science

Pusapati, A. V. Rama RajuA Robust Low Power Static Random Access Memory Cell Design
Master of Science in Electrical Engineering (MSEE), Wright State University, 2018, Electrical Engineering
Stability of a Static Random Access Memory (SRAM) cell is an important factor when considering an SRAM cell for any application. The Static Noise Margin (SNM) of a cell, which determines the stability, varies under different operating conditions. Based on the performance of three existing SRAM cell designs, 6T, 8T and 10T, a 10 Transistor SRAM cell is proposed which has good stability and has the advantage of reduced read power when compared to 6T and 8T SRAM cells. The proposed 10T SRAM cell has a single-ended read circuit which improves SNM over the 6T cell. The proposed 10T cell doesn’t require a pre-charge circuit and this in-turn improves read power and also reduces the read time since there is no need to pre-charge the bit-line before reading it. The Read SNM and Hold SNM of the proposed cell at a VDD of 1V and at 25°C is 254mV. The measured RSNM, HSNM and Write SNM at temperatures 0°C, 40°C, 80°C and 120°C and also at supply voltages 1V, 0.8V and 0.6V show the design is robust. The Write SNM of the proposed cell at a VDD of 1V and Pull-up Ratio of 1 is 275mV. Finally, a 32-byte memory array is built using the proposed 10T SRAM cell and the read, write times are 149ps and 21.6ps, respectively. The average power consumed by the 32-byte array over a 12ns period is 13.8uW. All the designs are done in the 32nm FinFET technology.

Committee:

Saiyu Ren, Ph.D. (Advisor); Ray Siferd, Ph.D. (Committee Member); Marian K. Kazimierczuk, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Static RAM; SRAM; Memory

Herbert, JosephThermal Analysis of a Permanent Magnet Assisted Synchronous Reluctance Motor Using Lumped Parameter Thermal Modeling
Master of Science, University of Akron, 2017, Electrical Engineering
With the advent of high power density motors in applications such as electric vehicles, the need for an effective thermal analysis of motors is further warranted to ensure their efficient and reliable operation. While existing Lumped Parameter Thermal Models (LPTMs) provide a convenient method for the thermal evaluation of motor designs, they provide a single, average temperature of the various regions of the motor without data on the temperature variation in the axial direction. LPTMs are a convenient reduced finite-element method to analyze the thermal performance of electric motors based on their design parameters and operating conditions. In this thesis the thermal analysis of a Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) is conducted by proposing two LPTMs: 1. Radial Lumped Parameter Thermal Model (R-LPTM). 2. Axial Lumped Parameter Thermal Model (A-LPTM). The R-LPTM adopts an existing approach considered for the thermal modeling of interior rotor configurations with the key contribution being the modeling of the unique rotor con figuration of the PMa-SynRM under study. In this approach, the individual geometries of the motor are modeled as single nodes, the voltages of which correspond to the average temperature for the respective machine part. The A-LPTM introduces a novel thermal model by employing the Finite Volume Method (FVM). While the R-LPTM models heat flow only in the radial direction due to the lamination structure of the stator and the rotor regions, the extension of this approach to the axially thermally shorted conductor coil sides, the magnets and the shaft results in a relative oversimpli cation of the heat transfer in these regions. While equivalent lumped thermal resistances model axial heat flow in these regions in the R-LPTM, by employing the FVM in the A-LPTM a higher resolution of axial temperature data is determined by providing a more accurate method of radial and axial heat flow modeling in these regions. In this model, the conductors, magnet and shaft nodes are evaluated as a function of the position along the axial length of the machine to determine their corresponding axial temperature variation. The results of both the thermal models formed in this thesis have been evaluated and the results were compared with both experimental and Finite Element Analysis (FEA) data. The experimental data was determined using temperature sensors mounted at various points in the machine. For the temperature measurement of the magnet an innovative Printed Circuit Board (PCB) integrated with sensors and wireless data transmission capabilities was mounted on the rotor for real time axial temperature measurement of the magnets. An analysis comparing the data from the R-LPTM and the A-LPTM shows the advantages of the A-LPTM. Additionally, plots of the accuracy of data obtained from both the models clearly highlights their respective accuracy when compared to the experimentally measured values. Lastly, a sensitivity analysis of both models was determined as a function of the thermal resistance values to establish the dependency of the accuracy of the thermal resistance determination on system.

Committee:

Seungdeog Choi (Advisor); Guo-Xiang Wang (Committee Member); Malik Elbuluk (Committee Member); Jin Kocsis (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Lumped Parameter Thermal Model; PMa-SynRM; Permanent Magnet Assisted Synchronous Reluctance Motor

Handagala, Suranga MSpecial Relativistic Array Multi-Port Circuits with Spacetime Noise-Shaping
Master of Science in Engineering, University of Akron, 2017, Electrical Engineering
The dramatic growth in mobile data services and increased demand of subscribers will pose tremendous challenges for the design of future communication systems. The ever increasing need for communication bandwidth and multiple access has made current 4G technologies approach their limits. Extensive research is currently underway to develop communication systems to achieve both capacity and multiple access for an exponentially increasing number of connections. The future of wireless communication will employ millimeter wave (mmW) technologies that have a broad underutilized spectrum. Design of such devices and networks will bring challenges in terms of metrics such as chip area, complexity and power consumption. Inspired by recent trends in mmW technologies, this thesis introduces novel architectures for improving power efficiency, linearity and fabrication cost for receiver-end electronics used in array processing radio receivers. We introduce the concept of delta-sigma noise shaping in the spatial dimension, an approach that pushes undesirable noise and non-linearities of receiver-end devices towards higher spatial frequencies. This method will enable the design of highly compact, fast, power efficient devices which will make future communication systems achieve exponential performance gains.

Committee:

Arjuna Madanayake (Advisor); Ryan Toonen (Committee Member); Kye-Shin Lee (Committee Member); Joan Carletta (Committee Member)

Subjects:

Electrical Engineering

Miller, William HAnalog Implementation of DVM and Farrow Filter Based Beamforming Algorithms for Audio Frequencies
Master of Science in Engineering, University of Akron, 2018, Electrical Engineering
Beamforming is a signal processing technique that is utilized in many communications and signal processing applications. Beamformers help to improve signal quality and enhance the performance of sensor networks and communications arrays. Current digital design methods may require the use of an FPGA or ASIC to perform signal processing. These implementations can be very expensive in terms of design cost and production cost. For this reason, it is worth investigating analog design approaches which can be implemented efficiently and inexpensively using analog design techniques. This thesis explores the recent developments in method and algorithm, and demonstrates applicability to analog beamforming. Two algorithms are investigated and tested: the Delay Vandermonde Matrix (DVM) and a novel analog implementation of the Farrow filter. The DVM design implements a five-beam multi-beam beamformer while the analog Farrow filter implements a single beam which is steerable in the range of 0º to 60º. These two algorithms are analyzed in the analog domain and prototype designs were developed, built, and tested in the laboratory. The prototype designs implemented audio beam-forming using analog electronic components for a four-element array of miniature speaker drivers. A 64-element array of miniature speaker drivers was also analyzed and tested using the same prototype designs. The results from these prototype designs were analyzed and show that a 10dB to 15dB beam intensity can be achieved with the speaker arrays. The results demonstrate that the analog design approach can be a viable and cost effective alternative to typical digital design approaches. This research may have specific applications to teleconference, home theater, virtual reality, and other audio applications.

Committee:

Arjuna Madanayake, PhD (Advisor); Hamid Bahrami, PhD (Committee Member); Kye-Shin Lee, PhD (Committee Member)

Subjects:

Acoustics; Computer Engineering; Electrical Engineering; Engineering

Keywords:

beamformer; delay vandermonde matrix; farrow filter; all-pass filter; audio beamformer; directional loudspeaker; analog audio; audio beamforming; array loudspeaker; array speaker; directional speaker array; multi-beam beamforming

Yang, ZhaoyuanAdversarial Reinforcement Learning for Control System Design: A Deep Reinforcement Learning Approach
Master of Science, The Ohio State University, 2018, Electrical and Computer Engineering
We adapt idea of adversarial reinforcement learning to numerical state inputs of controllers. We propose an idea of generating adversarial noises for inputs of controllers using deep reinforcement learning. We also propose an idea of using reinforcement learning agent as observer and using observer to reduce effect of adversarial noise. Idea of using reinforcement learning as observer may be helpful for adapting knowledge from simulation to real world. We performed a sequence of analyses about adversarial reinforcement learning and deep reinforcement learning. Through analysis, we discover deep reinforcement learning agent learnt in ideal environment is not robust to adversarial noise and learning in adversarial environment will make agent robust in both adversarial and non-adversarial environment. We make several conjectures about phenomena we observe, and propose an idea of how to let deep reinforcement learning agent better use state information. We also propose an idea of how to use neural network to find policies optimize cost objective automatically. In the end, we discuss possible works could be done in the future.

Committee:

Abhishek Gupta (Advisor); Wei Zhang (Committee Member)

Subjects:

Artificial Intelligence; Computer Science; Electrical Engineering; Engineering

Keywords:

deep reinforcement learning; control system; adversarial reinforcement learning; machine learning

Casto, Matthew JamesMulti-Attribute Design for Authentication and Reliability (MADAR)
Doctor of Philosophy, The Ohio State University, 2018, Electrical and Computer Engineering
Increased globalization of design, production, and independent distribution of integrated circuits (ICs) has provided adversarial and criminal opportunity for strategic, malicious, and monetary gain through counterfeiting, cloning, and tampering, producing a supply chain vulnerable to malicious or improper function and degraded reliability. Military, commercial avionics, medical, banking, and automotive systems rely on components providing high security, high reliability operation, and the impact can be large in terms of safety, readiness, mission success, and overall lifecycle cost when tampered parts find their way into the supply chain. Likewise, commodity platforms, such as the Internet of Things (IoT), rely on each networked component providing trustworthy authentication and identification, which has proven to be extremely vulnerable to cloning and spoofing when implemented through software or firmware solutions. Across these platforms, major effort has been focused on enhancing hardware assurance through intrinsic and unique physical hardware traits. Previous hardware authentication and identification techniques have targeted digital solutions that require increased logic overhead in order to obtain adequate uniqueness, have a limited number of implementation architectures, and suffer from significant environmental instabilities. In this work, the process-induced variation response of analog mixed-signal (AMS) circuits is investigated to yield foundational anti-counterfeiting, anti-cloning, design and characterization techniques. It explores unique behaviors termed Process Specific Functions (PSFs) to identify and group circuits of the same pedigree and provide traits for authentication, individual chip identification, and reliability monitoring. PSFs are demonstrated through the expansion of fundamental quantization sampling theory to produce a statistically bounded digital to analog converter model as implemented within a transmitter architecture. Simulation capabilities showed predictable circuit traits, including random process variations for authentication and unique ID. The model showed 90% Probability of Detection (PoD) with less than a 10% false alarm rate for an individual process specific cloning scenario, demonstrating foundational design capability for AMS counterfeit prevention and identification. The work makes significant progress towards quantifying design specific authentication behavior for the first time in analog ICs. A parameter space of harmonic amplitude responses is correlated to random and systematic process variations to produce challenge driven non-linear quantifiable and measurable distribution responses. These unique authenticity and reliability characteristics are related to physical process models in a low power 90nm CMOS, and are expanded for unique identification in a 130nm SiGe process technology. Collectively, this work provides an in-situ novel and foundational analog integrated circuit (IC) supply chain risk management (SCRM) and hardware security design framework.

Committee:

Waleed Khalil (Advisor)

Subjects:

Electrical Engineering

Keywords:

Authentication; Unique ID; Hardware Security; Analog Mixed-Signal; Supply chain risk management; trusted electronics; digital to analog converter; Reliability

Mao, DavinBistatic SAR Polar Format Image Formation: Distortion Correction and Scene Size Limits
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
The polar format algorithm (PFA) for bistatic synthetic aperture radar (SAR) image formation offers the compromise between image quality and computational complexity afforded by PFA, while enabling the geometric flexibility of a bistatic collection scenario. The use of the far-field approximation (FFA), which enables the use of the two-dimensional (2D) fast Fourier transform (FFT) in PFA, introduces spatially-varying distortion and defocus effects causing geometric warping and blurring in the resulting image. In this thesis, the residual phase errors due to the FFA are analyzed by decomposing the residual phase errors in the time dimension into their constant, linear, and quadratic Taylor series components. Based on the analysis, a 2D interpolation-based distortion correction technique is developed, and accurate scene size limits are derived for the corrected image to mitigate the effects of defocus. The phase error analysis is conducted with respect to arbitrary transmitter and receiver trajectories, and examples are demonstrated for both the ideal linear and ideal circular flight geometries using a point target scene simulation.

Committee:

Brian Rigling, Ph.D. (Advisor); Michael Saville, Ph.D. (Committee Member); Joshua Ash, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Remote Sensing

Keywords:

bistatic radar, synthetic aperture radar, polar format algorithm, distortion, defocus, scene size limits

Bhattarai, SmrityDigital Architecture for real-time face detection for deep video packet inspection systems
Master of Science, University of Akron, 2017, Electrical Engineering
Face detection and optional recognition is a highly researched area in digital image processing. Face detection allows gathering of statistical data from video sequences, with applications in a variety of areas such as bio-metrics, information security, and video surveillance. The growing abundance of video sensors that are connected to the internet require high-throughput real-time processing of a multitude of digital video feeds, where each feed provides independent real-time statistics of the number of persons shown in the feed. Typical applications include pedestrian counting, public transit monitoring, crowd control, and sporting events. Video surveillance and security applications in particular can benefit from real-time algorithms that can process large amounts of data. Thousands of video sources must be monitored for extracting situational awareness information for homeland security and public safety applications, and the manual monitoring of such a vast amount of data is nearly impossible. Algorithms for both face detection [1–4] and recognition [3, 5–7] take two main approaches involving the local detection of facial features based on a geometric model of the human face [8] and a holistic based feature recognition, where the image data is treated as an entity without isolating different regions of the face. The main challenge in feature based facial detection is identification and location of human faces regardless of their pose, facial expression, orientation, imaging condition or presence of structural components [9]. Some advanced image-based pattern recognition techniques have been developed to handle difficult scenarios like multiple faces, faces of different sizes, and even detection in heavily cluttered backgrounds. [8] In this thesis, we explore how hardware computing architecture for detection of an image, as a face or non-face, is designed. The computing architecture is first designed, modeled, and tested in MATLAB simulink using Xilinx blockset. Images were later tested using a Virtex-6 FPGA ML605 Evaluation Kit. A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a user or a designer after manufacturing. The system uses the features of a face and non-face, which were previously extracted by training the set of face and non-face patterns. The system is fully feature based and does not require any assumptions for processing. In this approach, all the images are treated in the same way. They are not separated into different categories before processing them. The system is basically a combination of different modules like convolution, sub-sampling, bias add, scaling, neuron and decision combined in a specific format to classify the images as a face or non-face on the basis of the output. The algorithm is simple without any need for preprocessing of the image. The performance trade-off exists between the computational precision, chip area, clock speed, and power consumption.

Committee:

Dr. Arjuna Madanayake (Advisor); Dr. Ryan C Toonen (Committee Member); Dr. Kye-Shin Lee (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Face detection, Convolutional Neural Network, Image processing

Abdelfattah, MoatazSwitched-Capacitor DC-DC Converters for Near-Threshold Design
Doctor of Philosophy, The Ohio State University, 2017, Electrical and Computer Engineering
With the increasing power and thermal limits in the computing industry, energy-efficient computing has become an urging necessity. Therefore, a surge of interest has been recently given to the concept of Near-Threshold Computing (NTC) as a potential candidate to realize energy-efficiency in computations. By operating at supply voltages near the transistor’s threshold voltage, NTC promises significant energy savings with moderate performance loss, which can be compensated for through parallelism. However, NTC faces a few challenges that hinder its wide adoption. On top of these challenges are the harsh specifications required for the power management and delivery units. Specifically, a power converter in an NTC system is required to achieve high efficiency at high current densities and low output voltages while seamlessly integrated on-chip, which are all contradicting specifications. To tackle the problem of energy-efficient computing, this research work addresses the challenges of NTC, with focus on power delivery. To do so, first, the target application of NTC is investigated to acquire the basic understanding of its challenges, opening doors for innovations and solutions for these challenges. Based on this understanding, which reveals the importance of power delivery for NTC and defines the requirements on power converters, most of the work in this thesis will focus on Switched-Capacitor (SC) power converters, which are found to be the most suitable type of converters for NTC. Therefore, a detailed study and literature review of SC converters is carried out. This study provides an in-depth understanding of SC converters operation, mechanisms, and challenges. Specifically, it is demonstrated that the most advantageous characteristic of SC converters is their compatibility with CMOS integration, while the most challenging aspect is their limited current density. Consequently, this thesis sets forth to address this challenge and proposes two solutions to boost the current density of SC converters, and thus, offering feasible power converter architectures for NTC. The first solution proposed in this thesis focuses on the control loop of SC converters. Unlike regular control loops, which often utilize frequency, capacitance, or conductance modulation, the proposed technique combines all three control knobs. The combination of these parameters allows for ripple reduction without sacrificing current density, and thus, effectively increases the converter’s density. Furthermore, this combination of parameters maintains the efficiency near its peak across a wide range of load currents, which is another relevant feature for NTC. The second solution introduces the concept of resonant gate drivers to SC converters, increasing the converter efficiency with no impact on current density. This solution is implemented in 45 nm SOI technology and fabricated for validation. The measurement results demonstrate a 70% efficiency at 1 A/mm2 current density and 0.4 V output voltage, which is a new efficiency/current-density record in the near-threshold range. In summary, as a potential solution to the problem of energy-efficiency in computations, NTC and its challenges are investigated. To address its most critical challenge of power delivery, SC converters are studied and circuit techniques are proposed to boost their current density and offer a feasible power delivery for NTC applications.

Committee:

Waleed Khalil (Advisor)

Subjects:

Electrical Engineering

Keywords:

DC-DC Converter, Switched-Capacitor, Power Management, Fully-integrated, Near-Threshold Design, Near-Threshold Computing, Integrated Voltage Regulator

Rohit , Akanksha Optimization and Characterization of a Capillary Contact Micro-Plotter for Printed Electronic Devices
Master of Science (MS), Ohio University, 2017, Electrical Engineering & Computer Science (Engineering and Technology)
Printed electronics is emerging as an integral part of the electronic industry due to its low cost fabrication and flexibility of devices against the rigid and expensive technology using silicon. Various methods for printing have existed for a long time with inkjet printing being the most common method used for electronic devices. This thesis explores a new and innovative printed technology using a capillary based microplotting approach implemented via Sonoplot Microplotter II. Unlike the inkjet printing technique which prints in overlapping spots with resolution between 30µm-100µm, the Microplotting approach helps to prints continuous features with a higher resolution as low as 5 ¿¿. Capillary action is used to fill picoliter amount of ink into a micropipette which is used for printing. Thus, the focus of this thesis is the optimization of this new printing technology under various conductions using different conductive inks and on a broad range of substrates and different tip diameters. In addition, passive resistive, capacitive and inductive components were printed to characterize the printing process and operation of electrical devices under different conditions. The applications of this Microplotter was further demonstrated by printing a flexible resistive strain sensor. The procedures involved for the fabrication of micropipettes using a glass puller for different diameter tips attached to the dispenser head is also explained in this thesis.

Committee:

Savas Kaya (Advisor); Chris Bartone (Committee Member); Jeffrey Dill (Committee Member); Eric Stinaff (Committee Member)

Subjects:

Electrical Engineering; Nanotechnology

Keywords:

Printed Electronics; Microplotter; Capacitive; Indictive; Resistive; Micropipettes

Rodriguez, DuncanDEVELOPMENT OF A STANDARD FORM FOR CREATION OF AND CONVERSION TO GRIDLAB-D MODELS
Master of Sciences (Engineering), Case Western Reserve University, 2018, EECS - Electrical Engineering
Many software packages are available for power systems network simulation, some of which are freely available. GridLAB-D Is a popular open source choice for smart grid research and allows users to have complete control over the production of the network via C++ style object based programming of the model file. A lack of GUI restricts the use of the software to small hand written systems but lends itself to script based creation of large network models. To allow new users an easy way to learn how data is structured in GLD without having to immediately learn the language and to provide better tools for conversion into GLD models, a standard data format is created. This standard can be used to manually format data and have model data automatically converted to. Data in this form can then be converted into a GLD model using a MATLAB script

Committee:

Kenneth Loparo (Committee Chair); Marija Prica (Committee Member); Vira Chankong (Committee Member)

Subjects:

Electrical Engineering; Energy

Keywords:

GridLAB; GridLAB-D; electric; energy; distribution; analysis; simulation

Khalili, FatemehDesign and Simulation of Coded-Modulation Using Turbo Trellis Coding and Multi- Layer Modulations
Doctor of Philosophy (PhD), Ohio University, 2017, Electrical Engineering & Computer Science (Engineering and Technology)
For modern wireless communication systems bandwidth efficiency and energy efficiency are the vital requirements for reasonable performance. Bandwidth determined by the rate at which information can be sent via the channel and the maximum rate at which error free information can be communicated is introduced as channel capacity by Shannon. Bandwidth efficiency or spectral efficiency is often satisfied by exploiting appropriate modulation scheme. Energy efficiency or power efficiency depends on the amount of power that a system uses which is a critical issue for wireless and cellular communications. It also shows the system tolerance against the environment noise. Energy efficiency can be improved by applying error correcting codes that produces lower error probability at the receiver for a fixed signal to noise ratio. In order to achieve both requirements, the idea of coded modulation technique which combines QPSK and OFDM modulation with a low rate, short block systematic turbo code, is proposed. We aim to achieve exceptional energy efficiency in extremely noisy environments, where moderate data rates and short messages are required. For this proposed model, the performance improvement is produced by a unique mapping of trellis structure error correcting code and spectral efficiency is achieved by exploiting OFDM modulation. The designed OFDM distributes systematic and parity symbols along all sub-channels symmetrically and adjusts their power distinctively to achieve superior bit error performance. Further, we utilize four-dimensional M-ary Quadrature Amplitude Modulation (4D-MQAM) for parity symbols which effectively increases the overall rate of the system while maintaining the same level of energy efficiency. Moreover, we apply puncturing for parity symbols to increase overall rate of the system and improve bandwidth efficiency. Also, we applied non-systematic coding structure to increase coding rate with less puncturing rate while maintaining the error rate as low as possible. The resulting performance of our designed system compared with the theoretical sphere packing lower bound indicates a very small gap (less than 0.5 dB) which means a substantially close approach to the Shannon limit.

Committee:

Jeffrey Dill, Dr (Advisor)

Subjects:

Electrical Engineering

Keywords:

Coded Modulation; Turbo Trellis Coding; Multi-Layer Modulation; Sphere Packing Bound

Li, MaoSpatial-temporal classification enhancement via 3-D iterative filtering for multi-temporal Very-High-Resolution satellite images
Master of Science, The Ohio State University, 2018, Electrical and Computer Engineering
It has been widely studied utilizing spatial-temporal remote sensing images to interpret ground objects. Due to the spectral ambiguities caused by inevitable factors like meteorological conditions, sunlight illumination, sensor radiation performance and earth objects reflectance, the interpretation accuracy of multi-class classification using a single temporal image is unsatisfactory. Under the hypothesis that earth objects have the temporal consistency, this thesis proposes a classification accuracy enhancement approach that utilizes 3-D temporal very-high-resolution images, where the digital surface model is generated through stereo dense matching. In the first place, the probability distribution of images’ coverage areas is derived from the supervised Random Forest Classifier. Then, the proposed method iteratively filters the probability maps with a 3-D bilateral filter which is built upon the domain of spectrum, spatial and height information of surface. Compared with single filtering enhancement studied before, continuously message passing from data in different dates can be achieved by iteratively filtering until the probability converge. It is conducted that each of the three experiments on 8 temporal consistent images presents convincing different types of city layout in Port-au-Prince, the capital of Haiti, including open grounds, dense residential and educational areas. After classification enhancement, the overall classification accuracy is increased by 2%~6%. The presenting results illustrate that although the study areas experienced a devastating earthquake leading to significant changes in the city landscape, the constraint on surface height effectively eliminates pre-enhancing classification errors. Furthermore, although the first filtering contributes the most on classification accuracy enhancement, this approach is manifested to consistently enhance the classification performance for similar earth objects like road and ground, permanent shelters and buildings through further iterations.

Committee:

Rongjun Qin, Dr. (Advisor); Desheng Liu, Dr. (Committee Co-Chair)

Subjects:

Computer Engineering; Computer Science; Electrical Engineering; Geographic Information Science; Geography; Remote Sensing

Keywords:

Image Enhance; Spatiotemporal probability bilateral filter; Random Forest, Classification

Alanazi, Turki Mohammed J.Electronic Protection Using Two Non-Coherent Marine Radars
Doctor of Philosophy (Ph.D.), University of Dayton, 2018, Electrical and Computer Engineering
The goal of this research is to develop a method that allows for the processing of bistatic modified non-coherent marine radar’s signals coherently, for the purpose of the warfare and electronic protection. Since the marine radar transmit signal is a non-coherent signal, it makes it difficult for the jammer to deceive the radar. Each marine radar is physically modified to work coherently and then configured to form bistatic radar. In this work, a method is presented for coherent processing of signals from a bistatic magnetron oscillator based marine radar. The feasibility of this approach was previously demonstrated for a monostatic radar through a hardware modification that allowed for capture of data and processing in PC. It is demonstrated here that operating two radars in this manner and combining their resulting signals allows for an improvement in overall detection and tracking. Our approach works by sampling the transmitted and received signals at each radar. Cross-correlations between all four combinations of transmitted and received signals are used to demonstrate the limits due to mutual interference in a bistatic/multistatic system of radars. This processing is successfully demonstrated in software, showing the potential for coherency between two marine radars. In general, bistatic coherent radars are very expensive, and this work provides a method for achieving the equivalent coherent performance using two modified non-coherent radar systems.

Committee:

Michael Wicks, PhD (Advisor)

Subjects:

Electrical Engineering

Keywords:

DRFM; electronic protection; non-coherent radar; bistatic radar; radar detection and tracking; cross-correlation

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