Engineering Commons^™

System Design And Implementation For Hybrid Network Function Virtualization, Xuzhi Zhang

Doctoral Dissertations

With the application of virtualization technology in computer networks, many new research areas and techniques have been explored, such as network function virtualization (NFV). A significant benefit of virtualization is that it reduces the cost of a network system and increases its flexibility. Due to the increasing complexity of the network environment and constantly improving network scale and bandwidth, it is imperative to aim for higher performance, extensibility, and flexibility in the future network systems. In this dissertation, hybrid NFV platforms applying virtualization technology are proposed. We further explore the techniques used to improve the performance, scalability and resilience of …

Design And Implementation Of An Isfet Sensor With Integration Of An On-Chip Processor, Shaghayegh Aslanzadeh

Doctoral Dissertations

Portable sensors are used in many applications. Among them, pH sensors are suitable for quantifying and identifying various analytes in real-time and doing so non-invasively. The analytes may have environmental impact such as in water quality monitoring. The analytes may also have biological impact such as monitoring cell culture or remote patient health assessment. CMOS based sensors are compact and enable low power consumption suitable for these portable applications.

This work reports on the development of a portable CMOS based pH sensor. The contributions of this dissertation are as follows. First, a differential pH sensor, with two different sized electrodes …

State Estimation For Vsc-Mtdc Power Systems Considering Droop Control And Operating Limits, Wei Feng

Doctoral Dissertations

Power systems with voltage source converter-based multi-terminal DC (VSC-MTDC) have received great interest in both the academic and industrial worlds in recent years. The introduction of VSC-MTDC systems into the power system industry brings not only significant benefits but also severe challenges due to the complex structures, different operating behaviors, and dynamic features of VSC-MTDC. State estimation (SE), an important function in the Energy Management System (EMS) for real-time monitoring, has become a challenging issue for VSC-MTDC systems. The traditional approach to dealing with this problem only considers the quasi-steady status of a VSC and ignores its dynamic features. Therefore, …

Arc Flash In Single-Phase Electrical Systems, John Francis Wade

Doctoral Dissertations

Arc flash and blast are hazards unique to electrical installations. Such events can start fires, destroy equipment, and severely injure or kill workers. NFPA 70E and IEEE 1584 are defining standards for arc flash hazard analysis used during system design, construction, and maintenance. Both focus on three-phase faults for calculations since three-phase power distribution is predominant in utility and industrial applications. However, discussion of arc flash in single-phase systems prevalent in residential and commercial facilities is excluded. Single-phase faults can also occur in a variety of industrial and utility circumstances.

This dissertation explores historic background and treatment of arc flash …

Synchronized Measurement Data Conditioning And Real-Time Applications, Xianda Deng

Doctoral Dissertations

Phasor measurement units (PMU), measuring voltage and current phasor with synchronized timestamps, is the fundamental component in wide-area monitoring systems (WAMS) and reveals complex dynamic behaviors of large power systems. The synchronized measurements collected from power grid may degrade due to many factors and impacts of the distorted synchronized measurement data are significant to WAMS. This dissertation focus on developing and improving applications with distorted synchronized measurements from power grid. The contributions of this dissertation are summarized below. In Chapter 2, synchronized frequency measurements of 13 power grids over the world, including both mainland and island systems, are retrieved from …

Stability Analysis And Control Of Nonlinear Power System Oscillations, Xin Xu

Doctoral Dissertations

This work investigates the nonlinear oscillatory behaviors of multi-machine power systems. New model-based and measurement-based approaches are proposed for stability analysis and control of nonlinear oscillations.

For stability analysis, a recently proposed model-based nonlinear oscillation analysis method, nonlinear modal decoupling (NMD), is investigated on its ability in capturing the stability information of a multi-machine power system. From the differential-equation model of the power system, the NMD inversely constructs a set of 1-degree-of-freedom nonlinear oscillators, referred to as decoupled oscillators or subsystems, with each one corresponding to an oscillation mode of the original system. It is shown that retaining high order …

Development Of A Robust Wideband Gnss Rf Frontend With Resilient Interference Blocking, Farshid Tamjid

Doctoral Dissertations

Recently, there has been an increasing demand for GNSS systems’ use for numerous applications such as public security, disaster relief, weather forecast, transportation, hydrologic monitoring, aviation, navigation positions and so on. Such systems must have a wideband performance (1.16 GHz to 1.61 GHz), high quality reception (which requires antenna with low AR, high RHCP gain, high F/B ratio, and high RL), portable size, and low cost. Our efforts here are geared towards the receiving side of such communication. The antennas are the first stage of the long receiver chain. Development of such wideband high quality antennas is challenging as most …

Approaches To Studying Bacterial Biofilms In The Bioeconomy With Nanofabrication Techniques And Engineered Platforms., Michelle Caroline Halsted

Doctoral Dissertations

Studies that estimate more than 90% of bacteria subsist in a biofilm state to survive environmental stressors. These biofilms persist on man-made and natural surfaces, and examples of the rich biofilm diversity extends from the roots of bioenergy crops to electroactive biofilms in bioelectrochemical reactors. Efforts to optimize microbial systems in the bioeconomy will benefit from an improved fundamental understanding of bacterial biofilms. An understanding of these microbial systems shows promise to increase crop yields with precision agriculture (e.g. biosynthetic fertilizer, microbial pesticides, and soil remediation) and increase commodity production yields in bioreactors. Yet conventional laboratory methods investigate these micron-scale …

Robust And Sustainable Energy Pathways To Reach Mexico’S Climate Goals, Rodrigo Mercado Fernandez

Doctoral Dissertations

As countries set climate change goals for adaptation and mitigation efforts, there are many questions regarding to how to reach these targets. These efforts will necessitate the transition of our electricity infrastructure from relying on conventional electricity generation technologies including natural gas, coal and oil, to clean energy generation with renewables. Through the three essays presented in this dissertation, we explore various pathways of development for the electricity system to reach long term climate change goals. We are interested in identifying: Is there a unique optimal development option or are there various? How do different mixes of electricity generation technologies …

Design And Implementation Of A Multi-Modal Sensor With On-Chip Security, Ava Hedayatipour

Doctoral Dissertations

With the advancement of technology, wearable devices for fitness tracking, patient monitoring, diagnosis, and disease prevention are finding ways to be woven into modern world reality. CMOS sensors are known to be compact, with low power consumption, making them an inseparable part of wireless medical applications and Internet of Things (IoT). Digital/semi-digital output, by the translation of transmitting data into the frequency domain, takes advantages of both the analog and digital world. However, one of the most critical measures of communication, security, is ignored and not considered for fabrication of an integrated chip. With the advancement of Moore's law and …

Modeling And Optimization Algorithm For Sic-Based Three-Phase Motor Drive System, Ren Ren

Doctoral Dissertations

More electric aircraft (MEA) and electrified aircraft propulsion (EAP) becomes the important topics in the area of transportation electrifications, expecting remarkable environmental and economic benefits. However, they bring the urgent challenges for the power electronics design since the new power architecture in the electrified aircraft requires many benchmark designs and comparisons. Also, a large number of power electronics converter designs with different specifications and system-level configurations need to be conducted in MEA and EAP, which demands huge design efforts and costs. Moreover, the long debugging and testing process increases the time to market because of gaps between the paper design …

Leveraging Conventional Internet Routing Protocol Behavior To Defeat Ddos And Adverse Networking Conditions, Jared M. Smith

Doctoral Dissertations

The Internet is a cornerstone of modern society. Yet increasingly devastating attacks against the Internet threaten to undermine the Internet's success at connecting the unconnected. Of all the adversarial campaigns waged against the Internet and the organizations that rely on it, distributed denial of service, or DDoS, tops the list of the most volatile attacks. In recent years, DDoS attacks have been responsible for large swaths of the Internet blacking out, while other attacks have completely overwhelmed key Internet services and websites. Core to the Internet's functionality is the way in which traffic on the Internet gets from one destination …

Ultra-Wideband True-Time-Delay Beamforming Networks In A Compact Package, Chris Merola

Doctoral Dissertations

The push for commercial technologies such as 5G Massive MIMO, and consumer broadband internet via low-earth-orbit satellite, drive a need for low cost phased array antenna technologies. A major obstacle in bringing this technology to market is the cost and complexity of the phased array antenna aperture and the required beamforming or multi-beamforming network. This dissertation presents an efficient, reliable, low-cost and mass-manufacturable multi-beamforming network solution. In accomplishing this, a new class of cavity-based, true-time delay multi-beamformer was devised and investigated. Rotman lens optics are implemented for broadband and low phase-error response. The presented topology offers reduction in size and …

Formal Verification Of Divider And Square-Root Arithmetic Circuits Using Computer Algebra Methods, Atif Yasin

Doctoral Dissertations

A considerable progress has been made in recent years in verification of arithmetic circuits such as multipliers, fused multiply-adders, multiply-accumulate, and other components of arithmetic datapaths, both in integer and finite field domain. However, the verification of hardware dividers and square-root functions have received only a limited attention from the verification community, with a notable exception for theorem provers and other inductive, non-automated systems. Division, square root, and transcendental functions are all tied to the basic Intel architecture and proving correctness of such algorithms is of grave importance. Although belonging to the same iterative-subtract class of architectures, they widely differ …

Information-Theoretic Limits On Statistical Matching With Applications To Privacy, Nazanin Takbiri

Doctoral Dissertations

Modern applications significantly enhance the user experience by adapting to each user's individual condition and/or preferences. While this adaptation can greatly improve a user's experience or be essential for the application to work, the exposure of user data to the application presents a significant privacy threat to the users- even when the traces are anonymized (since the statistical matching of an anonymized trace to prior user behavior can identify a user and their habits). Because of the current and growing algorithmic and computational capabilities of adversaries, provable privacy guarantees as a function of the degree of anonymization and obfuscation of …

Analysis And Verification Of Arithmetic Circuits Using Computer Algebra Approach, Tiankai Su

Doctoral Dissertations

Despite a considerable progress in verification of random and control logic, advances in formal verification of arithmetic designs have been lagging. This can be attributed mostly to the difficulty of efficient modeling of arithmetic circuits and data paths without resorting to computationally expensive Boolean methods, such as Binary Decision Diagrams (BDDs) and Boolean Satisfiability (SAT) that require ``bit blasting'', i.e., flattening the design to a bit-level netlist. Similarly, approaches that rely on computer algebra and Satisfiability Modulo Theories (SMT) methods are either too abstract to handle the bit-level complexity of arithmetic designs or require solving computationally expensive decision or satisfiability …

Trustworthy Systems And Protocols For The Internet Of Things, Arman Pouraghily

Doctoral Dissertations

Processor-based embedded systems are integrated into many aspects of everyday life such as industrial control, automotive systems, healthcare, the Internet of Things, etc. As Moore’s law progresses, these embedded systems have moved from simple microcontrollers to full-scale embedded computing systems with multiple processor cores and operating systems support. At the same time, the security of these devices has also become a key concern. Our main focus in this work is the security and privacy of the embedded systems used in IoT systems. In the first part of this work, we take a look at the security of embedded systems from …

Anti-Jam Gps Controlled Reception Pattern Antennas For Man-Portable Applications, Jeffrey A. Maloney

Doctoral Dissertations

Military GPS receivers provide crucial information to soldiers in the field, however, the performance of these devices is degraded by in band RF interference, making GPS susceptible to jamming. Anti-jam techniques for aircraft and vehicular platforms have been developed, but at present there is no system for dismounted soldiers. There is a need for an anti-jam system which meets the demands of a dismounted soldier and conforms to the size, weight, and power requirements of a portable device. A controlled reception pattern antenna, or CRPA, is a potential solution for jammer mitigation. These devices work by steering reception pattern nulls …

Design Of Hardware With Quantifiable Security Against Reverse Engineering, Shahrzad Keshavarz

Doctoral Dissertations

Semiconductors are a 412 billion dollar industry and integrated circuits take on important roles in human life, from everyday use in smart-devices to critical applications like healthcare and aviation. Saving today's hardware systems from attackers can be a huge concern considering the budget spent on designing these chips and the sensitive information they may contain. In particular, after fabrication, the chip can be subject to a malicious reverse engineer that tries to invasively figure out the function of the chip or other sensitive data. Subsequent to an attack, a system can be subject to cloning, counterfeiting, or IP theft. This …

Efficient Hardware Primitives For Securing Lightweight Systems, Siva Nishok Dhanuskodi

Doctoral Dissertations

In the era of IoT and ubiquitous computing, the collection and communication of sensitive data is increasingly being handled by lightweight Integrated Circuits. Efficient hardware implementations of crytographic primitives for resource constrained applications have become critical, especially block ciphers which perform fundamental operations such as encryption, decryption, and even hashing. We study the efficiency of block ciphers under different implementation styles. For low latency applications that use unrolled block cipher implementations, we design a glitch filter to reduce energy consumption. For lightweight applications, we design a novel architecture for the widely used AES cipher. The design eliminates inefficiencies in data …

Molecular Design Of Organic Semiconductors For Interfacial And Emissive Material Applications, Marcus David Cole

Doctoral Dissertations

This dissertation describes the synthesis and characterization of functional optoelectronically active materials. Synthetic techniques were used to prepare polymers containing perylene diimide (PDI) or tetraphenylethylene (TPE) moieties in the polymer backbone. PDI-based structures were prepared with embedded cationic or zwitterionic moieties intended to tailor organic/inorganic interfaces in thin film photovoltaic devices. The aggregation-induced emission (AIE)-active TPE polymers were synthesized to study how AIE properties evolve in π-conjugated polymers. The syntheses discussed here focused on modulation of molecular architecture to give rise to materials with tailored optoelectronic properties. Chapter 1 provides a brief overview of the field of organic electronics and …

Bandwidth Bounds Of Infinite Planar Array Elements, Hsieh-Chi Chang

Doctoral Dissertations

For elements of an infinite planar phased array in free space and an infinite conductor-backed free standing planar phased array, fundamental bandwidth bounds are derived from the optical theorem for periodic scatterers. The bounds are based on Gustafsson’s theory of fundamental bandwidth limits for electrically small antennas of arbitrary shape, but extended to periodic configurations. The element bandwidth bound is found to be a function of the strengths of the induced static dipole moments in constant background fields as well as the unit-cell dimensions and the scan angle. Explicit bandwidth bound expressions are found for narrowband and ultrawideband array cases. …

System Efficient Esd Design Concept For Soft Failures, Giorgi Maghlakelidze

Doctoral Dissertations

"This research covers the topic of developing a systematic methodology of studying electrostatic discharge (ESD)-induced soft failures. ESD-induced soft failures (SF) are non-destructive disruptions of the functionality of an electronic system. The soft failure robustness of a USB3 Gen 1 interface is investigated, modeled, and improved. The injection is performed directly using transmission line pulser (TLP) with varying: pulse width, amplitude, polarity. Characterization provides data for failure thresholds and a SPICE circuit model that describes the transient voltage and current at the victim. Using the injected current, the likelihood of a SF is predicted. ESD protection by transient voltage suppressor …

An Emi Characterization And Modeling Study For Consumer Electronics And Integrated Circuits, Chunyu Wu

Doctoral Dissertations

“As internet-of-things (IoT) applications surge, wireless connectivity becomes an essential part of the network. Smart home, one of the most promising application scenarios of IoT, will improve our life quality enormously. However, electromagnetic interference (EMI) to the receiving antenna, either from another electronic product or from a module/an integrated circuit(IC) inside the same wireless device, will degrade the performance of wireless connectivity, thus influencing the user experience. Characterization and modeling of the EMI become increasingly important.

In the first part, an improved method to extract equivalent dipoles from magnitude- only electromagnetic-field data based on the genetic algorithm and back-and-forth iteration …

Improved Attenuation And Crosstalk Modeling Techniques For High-Speed Channels, Shaohui Yong

Doctoral Dissertations

”As digital systems are moving in the direction of faster data transmission rate and higher density of circuits, the problem of the far-end crosstalk (FEXT) and frequency-dependent attenuation are becoming the major factors that limit signal integrity performance. This research is focusing on providing several more comprehensive and accurate modeling approaches for striplines on fabricated printed circuit board (PCB). By characterizing the dielectric permittivity of prepreg and core, dielectric loss tangent, and copper foil surface roughness using measurement data, a better agreement between the stripline model and measurement is achieved. First, a method is proposed to extract dielectric loss tangent …

Analysis And Modeling Of Power Supply Induced Jitter For High Speed Driver And Low Dropout Voltage Regulator, Yin Sun

Doctoral Dissertations

”With the scaling of power supply voltage levels and improving trans-conductance of drivers, the sensitivity of drivers to power supply induced delays has increased. The power supply induced jitter (PSIJ) has become one of the major concerns for high-speed system. In this work, the PSIJ analysis and modeling method are proposed for high speed drivers and the system with on-die low dropout (LDO) voltage regulator. In addition, a jitter-aware target impedance concept is proposed for power distribution network (PDN) design to correlate the PSIJ with PDN parasitic.

The proposed PSIJ analysis model is based on the driver power supply rejection …

Design And Fabrication Of Field-Effect Iii-V Schottky Junction Solar Cells, Amirhossein Ghods

Doctoral Dissertations

“A new concept of field-effect photovoltaic devices with a focus on design and fabrication of single and multi-junction solar cells using III-V materials has been shown and proved. Schottky solar cells based on metal-(insulator)-semiconductor (M-I-S) structure have been designed and fabricated using various wide bandgap semiconductors, such as GaAs and Al_0.3Ga_0.7As. A secondary bias layer has been introduced to the device structure, in which it creates additional band bending and subsequently depletion region at the flat band regions on the top surface of the device. It should be mentioned that the bias layer is designed to …

System Si/Pi Modeling And Analysis, Biyao Zhao

Doctoral Dissertations

"A physics-based circuit modeling methodology for 3D IC/packages is proposed here. The method is based on partial element equivalent circuit (PEEC) and layered Green's function (LGF). The LGFs are calculated from discrete complex image method (DCIM) with three terms, direct coupling, complex images, and surface wave, extracted to analyze the wave behavior. The dominate terms for LGFs are analyzed for four stack-ups in 3D IC/packages. Analytical formulas that include the contribution of complex images are proposed for partial capacitance calculation, with the complex image extracted from LGFs. A chip PDN geometry is used to illustrate the use of LGF in …

Operation And Analysis Of High-Voltage-Gain Dc-Dc Converters With Voltage Multipliers, Mohammad Rashed M. Altimania

Doctoral Dissertations

"This research analyzes and investigates the steady-state operations of four different high-voltage-gain step-up dc- dc converters to achieve a high gain. These topologies consist of a two-phase interleaved boost stage with three various voltage multiplier (VM) stages. The first stage of the first three topologies is the same, which is a two-phase interleaved boost stage implemented by using inductors. The first family used in this research is based on a modified Dickson charge pump voltage multiplier stage, and this family has been studied in discontinuous conduction mode (DCM). The second family relies on a non-inverting or inverting diode-capacitors voltage multiplier …

Strengthening Qc Relaxations Of Optimal Power Flow Problems By Exploiting Various Coordinate Changes, Mohammad Rasoul Narimani

Doctoral Dissertations

"Motivated by the potential for improvements in electric power system economics, this dissertation studies the AC optimal power flow (AC OPF) problem. An AC OPF problem optimizes a specified objective function subject to constraints imposed by both the non-linear power flow equations and engineering limits. The difficulty of an AC OPF problem is strongly connected to its feasible space's characteristics. This dissertation first investigates causes of nonconvexities in AC OPF problems. Understanding typical causes of nonconvexities is helpful for improving AC OPF solution methodologies.

This dissertation next focuses on solution methods for AC OPF problems that are based on convex …