Electrical Engineering and Computer Science

Congratulations New ECE PhDs: 2015–2016

Electrical and Computer Engineering conferred 45 PhD degrees in the Fall 2015, Summer 2016, and Winter 2016 semesters. Congrats to all of our outstanding new graduates!


Berk Altin
Prof. Kira Barton (ME Dept.), Dr. Berk Altin, Prof. Galip Ulsoy (ME Dept.), Prof. Jessy Grizzle

Berk Altin

Relaxing Fundamental Assumptions in Iterative Learning Control
Co-Chairs: Jessy Grizzle and Kira Barton

Iterative learning control (ILC) is perhaps best described as an open loop feedforward control technique where the feedforward signal is learned through repetition of a single task. As the name suggests, given a dynamic system operating on a finite time horizon with the same desired trajectory, ILC aims to iteratively construct the inverse image (or its approximation) of the desired trajectory to improve transient tracking. This dissertation moves from the idea of learning through repetition to two dimensional systems, specifically repetitive processes, that appear in the modeling of engineering applications such as additive manufacturing, and sketch out future research directions for increased practicality. More info

People Powering Innovation in Control Theory

Applications in robotics, additive manufacturing, flight control


Elnaz Ansari
Prof. Zhengya Zhang, Prof. David Wentzloff, Dr. Elnaz Ansari, Doug Carmean (Microsoft Research)

Elnaz Ansari

Design Automation of Low Power Circuits in Nano-Scale CMOS and Beyond-CMOS Technologies
Chair: David Wentzloff

Today’s integrated system on chips (SoCs) usually consist of billions of transistors accounting for both digital and analog blocks. Integrating such massive blocks on a single chip involves several challenges, especially when transferring analog blocks from an older technology to newer ones. This dissertation focuses on automating the design process of analog designs in advanced CMOS technology nodes, as well as reciprocal quantum logic (RQL) superconducting circuits.

People Powering Innovation in Low Power Circuits

Applications in personalized medicine, IoT


Suyong Bang
Prof. Katsuo Kurabayashi (Mech. Eng.), Dr. Suyong Bang, Prof. Dennis Sylvester, Prof. Zhengya Zhang

Suyong Bang

Circuit Techniques for Power Management Unit and Switched Capacitor DC-DC Converter
Chair: Dennis Sylvester

Efficient power management unit, efficient power conversion and energy efficient processor design have become important in the era of the Internet of Things (IoT), more than in the past, to address limited battery lifetime issue, which is mainly attributed to volume constraints and untethered property of IoT devices. In this work, such challenges have been tackled with the following solutions: ultra-low-power power management unit, ambient energy harvesting unit, and fully-integrated voltage down-conversion via switched-capacitor (SC) DC-DC converters. More info

People Powering Innovation in Integrated Circuits

Applications in IoT devices, ultra-low-power wireless sensor nodes


Md Baten
Dr. Md Baten, Prof. Pallab Bhattacharya, Prof. Jay Guo, Prof. Jamie Phillips

Md Zunaid Baten

Electrically Injected Exciton-Polariton Lasers
Chair: Pallab Bhattacharya

Conventional semiconductor lasers operate on the principle of stimulated emission of radiation. In contrast, exciton-polaritons or polaritons, which are part-light, part-matter Bosonic quasiparticles, offer an entirely different physical principle for realizing a coherent light emitter. These relatively new solid-state devices are commonly known as polariton lasers, which emit coherent light by spontaneous emission without the need for population inversion or stimulated emission. This study presents GaAs- and GaN-based polariton laser diodes which can operate at 155K and 300K, respectively. More info

People Powering Innovation in Lasers

Scientific breakthrough with applications in nextgen electronics


Beil

Ian Burkley Beil

Fast-timescale Control Strategies for Demand Response in Power Systems
Chair: Ian Hiskens

Concerns over climate change have spurred an increase in the amount of wind and solar power generation on the grid. While these resources reduce carbon emissions, the physical phenomena that they rely on - wind and sunlight - are highly stochastic, making their generated power less controllable. Demand-side strategies, which modulate load in a controllable manner, have been proposed as a way to add flexibility to the grid. Resources with innate flexibility in their load profile are particularly suited to demand response (DR) applications. This work examines two such loads: heating, ventilation, and air conditioning (HVAC) systems, and plug-in electric vehicle (PEV) fleets. More info

People Powering Innovation in Power & Energy

Applications in solar and wind grid integration, sustainability


Hatim Bukhari
Prof. Jerome Lynch (Civil and Env. Eng., Dr. Hatim Bukhari, Prof. Kamal Sarabandi, Prof. Anthony Grbic, Prof. Eric Michielssen

Hatim Bukhari

Antenna Bandwidth and Radiation Control by Topology and use of Non-Conductive Materials
Chair: Kamal Sarabandi

Ultra-wide-band (UWB) antennas have become one of the hottest topics in the last decade in wireless communications and radars. There are many different applications such as ground penetrating radars (GPRs) and wireless communication systems where such antennas are highly recommended and desired. The size of the antenna is also a major factor and design considerations must take into account the antenna size as well as is radiation characteristics into account. In this dissertation, a new approach in design of a cavity-backed coupled sectorial loop antenna (CB-CSLA) with directional radiation pattern is presented. More info

People Powering Innovation in Antennas

Applications in wireless communications, ground penetrating radars


Lin Chen
Prof. Becky Peterson, Prof. Wei Lu, Dr. Lin Chen, Prof. Cagliyan Kurdak (Physics), Prof. Zhaohui Zhong

Lin Chen

Vertical Integration of Germanium Nanowires on Silicon Substrates for Nanoelectronics
Chair: Wei Lu

Rapid development of the semiconductor industry in recent years has been primarily driven by continuous scaling, which allows for manufacturing integrated circuits with higher computing power at a reduced cost. As the size of the transistors approaches tens of nanometers, we are now faced with new technological challenges brought by aggressive scaling. To this end, unconventional semiconductor material and novel device structure have attracted a lot of interests as promising candidates to replace MOSFET with Si channel and help extend the Moore’s law. In this dissertation, we focus on Vapor-Liquid-Solid (VLS) synthesized Germanium nanowires with nanoscale size, and investigate their potential as electronic devices. More info

People Powering Innovation in Nanoelectronics

Applications in nextgen computers


Yu-Hui Chen
Prof. Selim Esedoglu (Mathematics), Prof. Al Hero, Dr. Yu-Hui Chen, Prof. Laura Balzano, Prof. Jeff Fessler

Yu-Hui Chen

Multimodal Image Fusion and Its Applications
Chair: Al Hero

Image fusion integrates different modality images to provide comprehensive information of the image content, increasing interpretation capabilities and producing more reliable results. There are several advantages of combining multi-modal images, including improving geometric corrections, complementing data for improved classification, and enhancing features for analysis...etc. This thesis develops the image fusion idea in the context of two domains: material microscopy and biomedical imaging. More info

People Powering Innovation in Imaging

Applications in microscopy and biomedical imaging


Thomas Frost
Prof. Jamie Phillips, Prof. Pallab Bhattacharya, Dr. Thomas Frost, Prof. Rachel Goldman, Prof. P.C. Ku

Thomas Frost

Red-Emitting III-Nitride Self-Assembled Quantum Dot Lasers
Chair: Pallab Bhattacharya

Visible light sources have numerous applications in the fields of solid state lighting, optical data storage, plastic fiber communications, heads-up displays in automobiles, and in quantum cryptography and communications. Most research and development into such sources is being done using III-nitride materials where the emission can be tuned from the deep UV in AlN to the near infrared in InN. However due to material limitations including large strain, piezoelectric polarization, and the unavailability of cheap native substrates, most visible devices are restricted to emission near GaN at 365 nm up to around 530 nm. Self-assembled InGaN/GaN quantum dots (QDs) can be epitaxially grown in the Stranski-Krastanow growth mode and can overcome many of these limitations. The first red emitting InGaN/GaN quantum dot lasers, emitting at up to 630 nm have been realized in the present study. More info

People Powering Innovation in Lasers

Applications in medicine, information processing, communication systems, displays


Krishna Chaitanya Garikipati
Dr. Krishna Garikipati (2nd from left) and friends

Krishna Chaitanya Garikipati

Towards Scalable Design of Future Wireless Networks
Chair: Kang Shin

Wireless operators face an ever-growing challenge to meet the throughput and processing requirements of billions of devices that are getting connected. In current wireless networks, such as LTE and WiFi, these requirements are addressed by provisioning more resources: spectrum, transmitters, and baseband processors. However, this simple add-on approach to scale system performance is expensive and often results in resource underutilization. To provide a more efficient option, this thesis explores several potential designs: utilizing unlicensed spectrum to augment the bandwidth of a licensed network; coordinating transmitters to increase system throughput; and finally, centralizing wireless processing to reduce computing costs. More info

People Powering Innovation in Wireless Communication Networks

Applications in IoT and mobile devices


Brent Griffin
Art Kuo, Ram Vasudevan, Prof. Jessy Grizzle, Dr. Brent Griffin, C. David Remy, Prof. Shai Revzen

Brent Griffin

Nonholonomic Virtual Constraints and Gait Optimization for Robust Robot Walking Control
Chair: Jessy Grizzle

Bipedal locomotion is well suited for mobile robotics because it promises to allow robots to traverse difficult terrain and work effectively in man-made environments. Despite this inherent advantage, however, no existing bipedal robot achieves human-level performance in multiple environments. A key challenge in robotic bipedal locomotion is the design of feedback controllers that function well in the presence of uncertainty, in both the robot and its environment. This dissertation addresses the design of feedback controllers and periodic gaits that function well in the presence of modest terrain variation, without reliance on perception or a priori knowledge of the environment. More info

People Powering Innovation in Control

Applications in Bipedal Robots


Michael Haines

Michael Haines

Ultrashort-Pulse Matter Interactions Using Compact Fiber CPA Technology
Chair: Almantas Galvanauskas

Chirped pulse amplification (CPA) was a breakthrough that allowed for high energy ultrashort pulses, leading to many technological and scientific discoveries. Many CPA systems relied on bulky, alignment-sensitive diffraction-grating based pulse stretchers and compressors, making them impractical for industrial applications. Chirped Bragg gratings (CBGs) have recently been demonstrated as compact, monolithic, and robust pulse stretchers and compressors, and so they are more practical for industrial applications. This thesis explores two key properties of CBGs: reciprocity and thermal loading. More info

People Powering Innovation in Ultrafast Lasers

Applications in biomedicine, industry, and material science



Xuejing He

Xuejing He

Energy Saving and Scavenging in Stand-alone and Large Scale Distributed Systems
Chair: Robert Dick

 This thesis focuses on energy management techniques for distributed systems such as hand-held mobile devices, sensor nodes, and data center servers. One of the major design problems in multiple application domains is the mismatch between workloads and resources. Sub-optimal assignment of workloads to resources can cause underloaded or overloaded resources, resulting in performance degradation or energy waste. This work specifically focuses on the heterogeneity in system hardware components and workloads. It includes energy management solutions for unregulated or batteryless embedded systems; and data center servers with heterogeneous workloads, machines, and processor wear states. More info

People Powering Innovation in Embedded Systems

Applications in mobile devices, sensor nodes, and data center servers


I-Ning Hu
Prof. Herb Winful, Prof. Alex Thomas (Nuclear Eng. and Rad. Sciences), Dr. I-Ning Hu, Prof. Almantas Galvanauskas, Dr. John Nees

I-Ning Hu

Study and Control of Nonlinearity in Large-Mode-Area Fibers
Chair: Almantas Galvanauskas

Practical advantages and high power of fiber lasers make them important in many scientific and industrial applications. However, relatively small mode-area and long propagation-length in an optical fiber also enhances the nonlinear interactions, posing certain limits on achievable average and peak powers in fiber lasers. In this dissertation, we explore such nonlinear effects and their control in CCC fibers, a practically important type of large-core effectively-single-mode fibers. More info

People Powering Innovation in Optics

Applications in fiber lasers for scientific and industrial applications


Wenbing Hu
Prof. Jamie Phillips, Prof. Wei Lu, Prof. Becky Peterson, Dr. Wenbing Hu, Prof. Emmanuelle Marquis (Materials Science and Eng.), Prof. Zhaohui Zhong

Wenbing Hu

Yttrium and Scandium in Solution-processed Oxide Electronic Materials
Chair: Becky Peterson

Large area electronics are critical for many novel applications such as smart windows, wearable electronics and Internet of Things. Among candidate materials, metal oxides have relatively good performance and stability and can be deposited by low‐cost solution processes. This thesis investigates the roles of rare‐earth elements yttrium and scandium as alloy components in a variety of solution‐processed metal oxide thin films. More info

People Powering Innovation in Devices and Nanotechnology

Applications in large-area electronics for smart windows, wearable electronics, IoT


Jaehun Jong
Dr. Jaehun Jeong, Prof. Michael Flynn

Jaehun Jeong

IF-Sampling Digital Beamforming with Bit-Stream Processing
Chair: Michael Flynn

An ADC-digital co-design approach to IF-sampling digital beamforming that combines continuous-time band-pass ΔΣ modulators (CTBPDSMs) and bit-stream processing (BSP) is presented. This approach enables power- and area- efficient DBF by removing the need for digital multipliers and multiple decimators. Digital down conversion and phase shifting are implemented with only multiplexers directly on the un- decimated CTBPDSM outputs. More info

People Powering Innovation in Integrated Circuits

Applications in antenna systems for radar, sonar, astronomy, acoustics, and wireless communications


Kim
Prof. Al Hero, Dr. Yelin Kim, Prof. Emily Mower Provost, Prof. Jason Corso, Prof. Honglak Lee

Yelin Kim

Automatic Emotion Recognition: Quantifying Dynamics and Structure in Human Behavior
Chair: Emily Mower Provost

Emotion is a central part of human interaction that has a huge influence on its overall tone and outcome. Today’s human-centered interactive technology can greatly benefit from automatic emotion recognition, as the extracted affective information can be used to measure, transmit, and respond to user needs. However, developing such systems is challenging since emotional expressions are complex and dynamic in terms of the inherent multimodality between audio and visual expressions, as well as the mixed factors of modulation that arise when a person speaks. To overcome this challenge, this dissertation presents data-driven approaches that can quantify the underlying dynamics and structure in audio-visual affective behavior. More info

People Powering Innovation in Human-Centered Computing


Phil Knag
Prof. Chris Ruf (Climate and Space Sci. and Eng.), Prof. Michael Flynn, Dr. Phil Knag, Prof. Zhengya Zhang

Phil C. Knag

Hardware Considerations for Signal Processing Systems: A Step Toward the Unconventional
Chair: Zhengya Zhang

Signal processing algorithms are becoming more computationally intensive and power hungry while the desire for mobile products and low power devices is also increasing. An integrated ASIC solution is one of the primary ways chip developers can improve performance and add functionality while keeping the power budget low. In this talk, Phil discusses ASIC hardware considerations for both conventional and unconventional signal processing systems, and how integration, error resilience, emerging devices, and new algorithms can be leveraged by signal processing systems to further improve performance and enable new applications.

People Powering Innovation in Integrated Circuits

Applications in signal processing systems, mobile and low-power computing


Heng Kuang

Heng Kuang

Concurrent Design of Assembly Plans and Supply Chains: Models, Algorithms, and Strategies
Co-Chairs: Jack Hu and Joenghan Ko

The outcome of this research are threefold: (1) it establishes a foundation for the research on integrated designs of assembly plans and supply chains as well as other concurrent design problems; (2) it offers a tool for integrated assembly plan and supply chain designs using which manufacturers can shorten the product development time, lower the product cost, and increase the responsiveness to fluctuations in supply chains; and (3) it provides a measure of the impact of product variety on inventory and insightful strategies to manage complicated assembly supply chains. More info

People Powering Innovation in Operations and Manufacturing

Applications in assembly plans and supply chains in manufacturing


Seungku Lee
Prof. Jerome Lynch (Civil and Env. Eng.), Prof. Anthony Grbic, Prof. Kamal Sarabandi, Dr. Seungku Lee, Prof. Amir Mortazawi

Seungku Lee

Design and Modeling of Ferroelectric BST FBARs for Switchable RF Bulk Acoustic Wave Filters
Chair: Amir Mortazawi

Multi-standard smartphones have become ubiquitous in everyday life. Such systems operate under different communication standards (2G, 3G, 4G-LTE, WLAN, GPS, Bluetooth, etc.) at different frequencies. Compact and high-performance filters are indispensable for RF front-ends in mobile phones, and RF bulk acoustic wave (BAW) filters, based on piezoelectric film bulk acoustic resonators (FBARs), have become prevalent. This dissertation presents one of the new promising technologies, known as intrinsically-switchable BAW filters employing newly-investigated electrostrictive effect in BST thin films. More info

People Powering Innovation in Electromagnetics

Applications in radios for mobile communications


Yang Liu
Prof. Vijay Subramanian, Prof. Al Hero, Dr. Yang Liu, Prof. Mingyan Liu, Prof. Grant Schoenebck (CSE)

Yang Liu

Harnessing the Power of Multi-Source Data: an Exploration of Diversity and Similarity
Chair: Mingyan Liu

This dissertation studies a sequence of problems concerning the collection and utilization of data from disparate sources, e.g., that arising in a crowd-sourcing system. It aims at developing learning methods to enhance the quality of decision-making and learning task performance by exploiting a multitude of diversity, similarity and interdependency inherent in a crowd-sourcing system and among disparate data sources. More info

People Powering Innovation in Data Science

Applications in network security and company risk policies


Yue Liu
Prof. Mingyan Liu, Dr. Yue Liu, Prof. Robert Dick, Prof. Vijay Subramanian

Yue Liu

Supporting Large Scale Communication Systems on Infrastructureless Networks Composed of Commodity Mobile Devices: Practicality, Scalability, and Security
Chair: Robert Dick

Infrastructureless networks composed of commodity mobile devices have the potential to support communication applications resistant to blocking and censorship, as well as certain types of surveillance.  We analyze the performance and energy consumption of such networks, and consider the impact of random and targeted denial-of-service and censorship attacks. More info

People Powering Innovation in Embedded Systems

Applications in mobile computing networks


Kevin Moon
Prof. Long Nguyen (Statistics), Prof. Al Hero, Dr. Kevin Moon, Prof. Clay Scott, Prof. Raj Nadakuditi

Kevin Moon

Nonparametric Estimation of Distributional Functionals and Applications
Chair: Alfred Hero

The large growth of digital technology and devices in recent years has led to an explosion in the availability of signals and data. This increase in data corresponds to increased research opportunities and challenges in signal processing and machine learning. One such challenge is the increased risk of overfitting in machine learning problems due to increased dimensionality. Large dimensional data can provide a very high resolution description of the objects being analyzed. However, with this high resolution comes the "curse of dimensionality" which requires a rapidly increasing amount of data samples as dimension increases to analyze the data without over?fitting. Two approaches to reducing the risk of overfitting are considered in this thesis. More info

People Powering Innovation in Signal Processing and Machine Learning

Applications in information theory and Big Data


Parinaz Naghizadeh Ardabili
Dr. Naghizadeh Ardabili (center, in black) and friends

Naghizadeh Ardabili

On the Provision of Public Goods on Networks: Incentives, Exit Equilibrium, and Applications to Cyber
Chair: Mingyan Liu

Attempts to improve the state of cyber security have been on the rise over the past years. The importance of incentivizing better security decisions by users is two-fold: it not only helps users protect themselves against attacks, but it further provides positive externalities to others interacting with them, as a protected user is less likely to become compromised and used to propagate attacks against other entities. As a result, security can be viewed as a public good. We take a game-theoretic approach to understanding users' incentives in the provision of public goods, and in particular, cyber security. More info

People Powering Innovation in Cyber Security

Applications in cyer security and economic incentives


Ugo Otuonye
Prof. Wei Lu, Dr. Ugo Otuonye

Ugo Otuonye

Nanoscale Photodetector and Optical Modulator for Future Optical Interconnect Systems
Chair: Wei Lu

As the demand for cheaper and faster computing continues to increase, the semiconductor industry has relied on transistor scaling to meet this demand. With transistor size approaching the atomic limit, there needs to be a fundamental change from the traditional improvement methods employed in the past. Switching to optical interconnects will eliminate most of the parasitic effects experienced with metal interconnects and will provide an immediate improvement in computing speed. To implement an optical interconnect system, nanoscale photodetectors and modulators will be required. We have demonstrated a single 20nm diameter germanium nanowire photodetector. More info

People Powering Innovation in Devices, Materials, and Nanotechnology

Applications in nextgen computing


Tai-Chuan Ou

Tai-Chuan Ou

Scalable Energy-Recovery Architectures
Chair: Marios Papaefthymiou

Energy efficiency is a critical challenge for today’s integrated circuits, especially for high-end digital signal processing and communications that require both high throughput and low energy dissipation for extended battery life. Charge-recovery logic recovers and reuses charge using inductive elements and has the potential to achieve order-of-magnitude improvement in energy efficiency while maintaining high performance. However, the lack of large-scale high-speed silicon demonstrations and inductor area overheads are two major concerns. This dissertation focuses on scalable charge-recovery designs, presenting a semi-automated design flow to enable the design of large-scale charge-recovery chips. More info

People Powering Innovation in Computer Architecture

Applications in energy-efficient computing


Yi Ouyang

Yi Ouyang

On the Interaction of Information and Decisions in Dynamic Networked Systems
Chair: Demos Teneketzis

Efficient operation of dynamic networked systems can significantly improve our quality of life. The operation of a dynamic networked system involves decision making processes by many decision makers (DMs) who may or may not have the same information, and may or may not share the same objective. The quality of each DM’s decision depends on the quality of information available for decision-making. Since the network is dynamic, the available information is a dynamic process that depends on the DMs’ decision rules. Information affects decisions, and decisions influence information. Research on the interaction between information and decisions plays a key role in determining efficient designs of modern social-technological systems. We study the impact of the information-decision interaction on system performance within the context of: (i) centralized stochastic control; (ii) decentralized stochastic control; and (iii) stochastic dynamic games with asymmetric information. More info

People Powering Innovation in Networked Systems

Applications in communication systems, power systems, surveillance systems


Paul Ozog
Dr. Paul Ozog, Prof. Ryan Eustice (Naval and Marine Eng.), Prof. Shai Revzen, Prof. Jason Corso, Prof.  Matthew Johnson-Roberson (Naval and Marine Eng.)

Paul Ozog

Advances in Simultaneous Localization and Mapping in Confined Underwater Environments Using Sonar and Optical Imaging
Chair: Ryan Eustice

This thesis reports on the incorporation of surface information into a probabilistic simultaneous localization and mapping (SLAM) framework used on an autonomous underwater vehicle (AUV) designed for underwater inspection. AUVs operating in cluttered underwater environments, such as ship hulls or dams, are commonly equipped with Doppler-based sensors, which—in addition to navigation—provide a sparse representation of the environment in the form of a three-dimensional (3D) point cloud. The goal of this thesis is to develop perceptual algorithms that take full advantage of these sparse observations for correcting navigational drift and building a model of the environment. More info

People Powering Innovation in Naval and Marine Engineering

Applications in underwater imaging


Sung-Yun Park

Sung-Yun Park

Area- and Energy- Efficient Modular Circuit Architecture for 1,024-Channel Parallel Neural Recording Microsystem
Chair: Euisik Yoon

In the past few decades, there has been significant progress in the development of neural recording systems as with fast advances in electronics and micro-electro-mechanical-systems (MEMS) technologies. The number of simultaneous recorded neurons has been doubled at every 7 years, following a trend similar to Moore’s law, although much slower. This research focuses on developing a system architecture and associated electronic circuit implementation for a modular, massive-parallel neural recording system capable of recording 1,024 channels simultaneously as a next-generation neuroscience research tool.

People Powering Innovation in MEMS and Microsystems

Applications in healthcare and neuroscience


Venkatram Pepakayala

Venkatram Pepakayala

Micromachined Magnetoelastic Sensors and Actuators for Biomedical Devices and Other Applications
Chair: Yogesh Gianchandani

Magnetoelastic materials exhibit coupling between material strain and magnetization. This coupling allows the interaction of the material with an external magnetic field, opening the door to the development of wireless transduction devices. Completely wireless and passive operation, and simplicity of design make this technology a worthy competitor to more mainstream transduction philosophies. Such features of magnetoelastic materials are of particular interest for development of novel applications in the field of implantable biomedical devices. More info

People Powering Innovation in MEMS and Microsystems

Applications in biomedical sensing devices


Matthew Prelee

Matthew Prelee

Manhattan Cutset Sampling and Sensor Networks
Chair: David Neuhoff

Cutset sampling is a new approach to acquiring two-dimensional data, i.e. images, where values are recorded densely along straight lines.  This type of sampling is motivated by physical scenarios where data must be taken along straight paths, such as a boat taking water samples.  Additionally, it may be possible to better reconstruct image edges by using the dense amount of data collected on straight lines.  Finally, an advantage of cutset sampling is in the design of wireless sensor networks.  If battery-powered sensors are placed densely along straight lines, then the transmission energy required for communication between sensors can be reduced, thereby extending the lifetime of the network. A special case of cutset sampling is Manhattan sampling, where data is recorded along evenly-spaced rows and columns.  This thesis primarily examines Manhattan sampling in three projects. More info

People Powering Innovation in Communications and Signal Processing

Applications in imaging and wireless sensor network design


David Reed

David Reed

Identification and Adaptive Control for High-performance AC Drive Systems
Chair: Heath Hofmann and Jing Sun

High-performance AC machinery and drive systems are used in a variety of applications ranging from robotics to vehicle propulsion. Such applications typically require high-bandwidth and tight regulation of position, speed and/or torque over a wide range of operating conditions. However, machine parameters can vary significantly, degrading the performance of the drive system. While adaptive control techniques can be used to estimate machine parameters online, parameter identification and control are typically conflicting objectives. In this dissertation, we present research into the development generalizable design methodologies for Simultaneous Identification and Control (SIC) of overactuated systems via case studies with Permanent Magnet Synchronous Machines (PMSMs). More info

People Powering Innovation in Power and Energy

Applications in robotics, motion control, vehicle propulsion


Patrick Sheridan

Patrick Sheridan

Neuromorphic Computing with Resistive Switching Devices
Chair: Wei Lu

Resistive switches, commonly referred to as resistive memory (RRAM) devices and modeled as memristors, are an emerging nanoscale technology that can revolutionize data storage and computing approaches. Enabled by the advancement of nanoscale semiconductor fabrication and detailed understanding of the physical and chemical processes occurring at the atomic scale, resistive switches offer high speed, low-power, and extremely dense nonvolatile data storage. This dissertation presents the investigation of tungsten oxide based resistive switching devices for use in neuromorphic computing applications.

People Powering Innovation in Devices and Nanotechnology

Applications in data storage and computing


Aaron Stein

Aaron Stein

The Design and Effect Power Electronics on Vibration-Based Energy Harvesting Methods
Chair: Heath Hoffman

Recent advancements in low-power sensor nodes have led to data acquisition systems for applications such as heart monitoring, and building environmental controls. Often these systems are in locations characterized by limited access to electrical power, yet are in the presence of ambient mechanical vibrations. Therefore, energy harvesting from mechanical vibrations is proposed as a solution for powering these wireless sensor nodes. This dissertation focuses on the power electronic interface between vibration energy harvesting devices and electrical energy storage elements for piezoelectric and variable-capacitance energy harvesting systems. More info

People Powering Innovation in Power and Energy

Applications in Energy Harvesting


Chu-Hsiagn Teng

Chu-Hsiang Teng

Strain Engineering of InGaN/GaN Nanopillars for Optoelectronic Applications
Chair: PC Ku and Hui Deng

Indium gallium nitride (InGaN)/gallium nitride (GaN) material system is critical for optoelectronic applications in LEDs and lasers because it has direct band gap and large oscillator strength, and the emission wavelength covers the entire visible spectrum. Due to the large lattice mismatch between InGaN and GaN, a large built-in strain exists in the InGaN layer. It is known that nanostructures have large surface-to-volume ratio and could help relax strain via free surfaces. In this work, I will present top-down InGaN/GaN nanostructures as an effective way to manipulate the strain and how we harness the strain effect to create more functionalities of optoelectronics devices. More info

People Powering Innovation in Optoelectronics

Applications in LEDs, lasers, quantum information, electronic devices


Alan Teran

Alan Teran

Spectrum-Dependent Photovoltaic Energy Harvesting
Chair: Jamie Phillips

Traditional photovoltaic research has been mostly focused on improving the efficiency and reducing the cost of solar cells. These efforts have been tailored towards large-scale applications in order to increase the deployment of solar energy technology and further reduce our dependence on non-renewable sources of energy. The improvements in traditional solar photovoltaics have opened the door to new, unique, applications that require their own research and development efforts. One of these applications is the need for high efficiency photovoltaics deployed in unconventional environments and requiring unique form factors. In this work, studies of n-ZnSe/p-ZnTe heterojunction solar cells grown by molecular beam epitaxy will be reported. More info

People Powering Innovation in Devices, Materials, and Nanotechnology

Applications in indoor energy harvesting, IoT


Brian Tierney
Prof. Anthony Grbic, Dr. Brian Tierney

Brian Tierney

Advances in Emerging Electromagnetics Topics: Metamaterials and Wireless Power Transfer
Chair: Anthony Grbic

Since their introduction 15 years ago, metamaterials have enabled the design of various new and exotic electromagnetic devices. These devices have included polarization convertors, beam refractors, absorbers, wave collimators, and many others. However, unlocking the full potential of metamaterials requires improving existing design methods. In this thesis, new techniques are proposed and demonstrated to overcome the deficiencies of current metamaterial design methods. More info

People Powering Innovation in Electromagnetics

Applications in metamaterials and wireless power transfer


Robert Vandermeulen
Prof. Raj Nadakuditi, Prof. Clay Scott, Dr. Robert Vandermeulen, Prof. Ambuj Tewari (Statistics), Prof. Al Hero

Robert Vandermeulen

Functional Analytic Perspectives on Nonparametric Density Estimation
Chair: Clay Scott

Nonparametric density estimation is a classic problem in statistics. In the standard estimation setting, when one has access to iid samples from an unknown distribution, there exist several established and well-studied nonparametric density estimators. Yet there remains interesting alternative settings which are less well-studied. This work considers two such settings. First we consider the case where the data contains some contamination, i.e. a portion of the data is not distributed according to the density we would like to estimate. Next we introduce a new robust kernel density estimator based on scaling and projection in Hilbert space. Finally we consider a different sort of setting which can be thought of as nonparametric mixture modelling. More info

People Powering Innovation in Signal Processing

Applications in Statistics and Data Science


Deepanshu Vasal
Prof. Mingyan Liu, Prof. Vijay Subramanian, Dr. Deepanshu Vasal, Prof. Achilleas Anastasopoulos, , Prof. Grant Schoenebck (CSE)

Deepanshu Vasal

Dynamic Decision Problems with Cooperative and Strategic Agents and Asymmetric Information
Chair: Achilleas Anastasopoulos

There exist many real world situations involving multiple decision makers with asymmetric information, such as in communication systems, social networks, economic markets and many others. In this dissertation, we attempt to enhance the conceptual understanding of such systems and provide analytical tools to characterize the optimum or equilibrium behavior. Specifically, we study four discrete time, decentralized decision problems in stochastic dynamical systems with cooperative and strategic agents. More info

People Powering Innovation in Dynamical Systems

Applications in communication systems, social networks, economic markets


Ning Wang
Prof. Mona Jarrahi, Dr. Ning Wang, Prof. Hui Deng

Ning Wang

High Sensitivity Terahertz Receivers Based on Plasmonic Photoconductors
Chair: Jay Guo and Mona Jarrahi

Terahertz radiation can offer unique functionalities in a wide range of applications including medical imaging, biosensing, industrial quality control, and security screening, etc. However, high power terahertz transmitters and high sensitivity terahertz receivers are necessary for practical feasibility of these applications. This PhD work is focused on new types of high sensitivity terahertz receivers based on plasmonic photoconductors. More info

People Powering Innovation in Terahertz Receivers

Applications in medical imaging, biosensing, industrial quality control, security screening


Xiaoyu Wang
Prof. Jerome Lynch (Civil and Env. Eng.), Prof. Heath Hofmann, Dr. Xiaoyu Wang, Prof. Amir Mortazawi, Prof. Anthony Grbic

Xiaoyu Wang

High Efficiency and High Sensitivity Wireless Power Transfer and Wireless Power Harvesting Systems
Chair: Amir Mortazawi

In this research, several approaches are described which improve the efficiency, sensitivity, and tolerance of wireless power transfer and wireless power harvesting systems. These include a nonlinear resonance circuit, a high sensitivity wireless power harvester, and a rectifier array circuit with an adaptive power distribution method. More info

People Powering Innovation in RF Circuits

Applications in wireless power transfer, wireless power harvesting systems, structural health monitoring systems


Jiangfeng Wu

Jiangfeng Wu

Radar Sub-surface Sensing for Mapping the Extent of Hydraulic Fractures and for Monitoring Lake Ice and Design of Some Novel Antennas
Chair: Kamal Sarabandi

Hydraulic fracturing, which is a fast-developing well-stimulation technique, has greatly expanded oil and natural gas production in the United States. As the use of hydraulic fracturing has grown, concerns about its environmental impacts have also increased. A sub-surface imaging radar that can detect the extent of hydraulic fractures is highly demanded, but existing radar designs cannot meet the requirement of penetration range on the order of kilometers due to the exorbitant propagation loss in the ground. In the thesis, a medium frequency (MF) band sub-surface radar sensing system is proposed to extend the detectable range to kilometers in rock layers. Also investigated is the application of imaging radars for sub-surface sensing frozen lakes at Arctic regions, and the design of high-performance antennas for the aforementioned radar remote sensing systems. More info

People Powering Innovation in Radar Remote Sensing

Applications in detection of hydraulic fractures, sub-surface sensing in the Artic


Yu Xiang
Prof. Al Hero, Dr. Yu Xiang, Prof. Jason Corso

Yu Xiang

3D Object Representations for Recognition
Chair: Al Hero and Sylvio Savarese

Object recognition from images is a longstanding and challenging problem in computer vision. The main challenge is that the appearance of objects in images is affected by a number of factors, such as illumination, scale, camera viewpoint, intra-class variability, occlusion, truncation, and so on. How to handle all these factors in object recognition is still an open problem. This dissertation presents efforts in building 3D object representations for object recognition. Compared to 2D appearance based object representations, 3D object representations can capture the 3D nature of objects and better handle viewpoint variation, occlusion and truncation in object recognition. More info

People Powering Innovation in Computer Vision

Applications in representing 3D objects


Shang Hua Yang
Prof. Herb Winful, Prof. Mona Jarrahi, Dr. Shang Hua Yang

Shang Hua Yang

Advanced Plasmonic Photoconductive Sources for Pulsed and Continuous-wave Terahertz Generation
Chair: Herb Winful and Mona Jarrahi

Terahertz technology has attracted extensive attention because of its unique applications in environmental monitoring, space explorations, chemical identification, security screening, medical imaging, and biological sensing. In the meantime, the practical feasibility of many terahertz systems is still limited by the relatively low power, low efficiency, and bulky nature of existing terahertz sources. This dissertation presents some of our recent results on achieving high-performance terahertz sources to mitigate performance limitations of existing terahertz systems. More info

People Powering Innovation in Terahertz Technology

Applications in environmental monitoring, space exploration, chemical identification, medical imaging, biological sensing


Cheng Zhang
Prof. Ted Norris, Prof. Jay Guo, Dr. Cheng Zhang, Prof. Anthony Grbic, Prof. Xiaogan Liang (Mech. Eng.)

Cheng Zhang

Optical Properties and Optoelectronic Applications of Nano-size Metallic Films and Metamaterials
Chair: Jay Guo

Future optical and optoelectronic devices are desired to have compact sizes, high efficiencies, robust performance and low manufacturing costs. All these advances call for developments both in their constituent materials and design concepts. This PhD thesis presents some of the recent developments of the above aspects. These include a new kind of silver, called doped silver, and a large-area, printed metasurface.

People Powering Innovation in Devices, Materials, and Nanotechnology

Applications in nextgen optical and optoelectronic devices