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Integrated Capacitive Power IC Solutions for Industrial Sensor Applications
No full textIntelligent sensor networks are incorporated in industrial automation systems to monitor
production environments in real time. The growth of sensor networks scales up power demands.
However, there are stringent size and cost constraints to industrial power solutions. It is imperative
to improve power density of power converters to facilitate this trend. Integrated circuits (ICs)
enable high-power-density designs by reducing solution sizes and bill of materials. Unlike
conventional power designs, industry-grade power converters must interface with a wide range of
voltage supplies and adapt to harsh environments. Therefore, it is challenging to implement
industrial power solutions on silicon. This dissertation focuses on addressing the design challenges
of chip-level power solutions for industrial applications. It provides system architectures, design
methodologies and circuit implementations to enhance power density and efficiency for fully-
integrated power designs.
Firstly, the dissertation presents a survey of existing DC-DC power converter topologies and
identifies the potential of the switched-capacitor topology for on-chip implementations. The
availability of high-density on-chip capacitors enables power converters to deliver large output
power and achieve high efficiency. But, there is a trade-off between the performance and the input
voltage range. A three-level switched-capacitor power converter is presented to mitigate this
challenge. Differing from the conventional structure, the proposed converter utilizes a tri-mode
operation. Not only does it reduce the number of required devices for large-conversion-ratio
operation, but also eases the voltage stress on each device. The power density of the proposed
structure is improved by using compact low-voltage devices. Meanwhile, based on the equivalent
model of switched-capacitor converters, the optimization to allocate area for flying capacitors
further enhances power density. On the circuit level, the power stage is implemented with all N-
type power switches and the bootstrapped driving scheme to minimize its size. To incorporate an
output capacitor on silicon, a three-phase system architecture is realized to suppress and balance
the output voltage ripple.
The galvanic isolation on the power path provides electrical protection for industrial applications.
The capacitive isolator is the only viable solution for monolithic integration. To enable power
delivery with low-density isolation capacitors, an isolated capacitive power transfer (ICPT) system
is presented. The ICPT system employs a resonant architecture. Inductors are used to cancel out
high impedance of isolation capacitors. The resonant effect not only increases power density, but
also eliminates power losses from switching bottom-plate parasitic capacitors. In addition, a sub-
harmonic operation scheme reduces the operating frequency for resonance and overcomes the
switching power loss. The power receiver is designed with a comparator-based active rectifier to
minimize the conduction loss while prevents shoot-through current. A digital isolated capacitive
feedback link is utilized to maintain power efficiency with a wide range of output power.
In this dissertation, all the proposed power converters have been fabricated and tested to
successfully demonstrate the proposed schemes, techniques, and circuits. The measurement results
successfully verify the effectiveness of the designs
Academic Advising Effects on First-generation Student Outcomes: an Evaluation Using Bourdieu’s Theory of Cultural Capital
No full textFirst-Generation students are often hindered by their limited understanding of how to
successfully navigate post-secondary institutions. They are also known to have limited access to
familial sources of support and guidance needed to succeed in completing a college degree.
Using Bourdieu’s theory of cultural capital, this study explores whether academic advising
contributes to their academic success. Current research on academic advising and cultural
capital theory suggests that institutional agents like academic advisors contribute to student
academic success by transmitting timely and relevant academic information, guidance, and
support. With the use of student-level data, this study explores the effects of academic advising
on the academic outcomes of First-Generation Students as measured by degree completion and
final cumulative GPA. This research expands the use of cultural capital theory to a higher
education setting within the context of the academic advising process. It also contributes to the
literature on educational attainment by providing support for academic advising as an
institutional factor that is associated with better educational outcomes of First-Generation
students. This study concludes with policy and program recommendations for more effective
academic advising programs aimed at First-Generation students, low-income, and traditional
minorities
Defect Tolerant Design: Improving Manufacturing Yield of Integrated Circuits
No full textThis dissertation presents a study on improving the manufacturing yield of integrated circuits
by advocating a defect-aware circuit design approach. In the latest technology nodes, there is
a growing concern regarding yield loss due to timing failures and delay degradation resulting
from manufacturing complexities. Largely, these manufacturing imperfections are fixed using
empirical methods such as Design for Manufacturability Guidelines (DFMGs) for the layout
and process fixes that are expensive and included during the final stages of the physical
design process. We propose a defect-tolerance framework for improving design yield by
taking advantage of existing Electronic Design Automation (EDA) tools to generate designs
with improved ability to withstand delay variations and process imperfections. By adopting
a defect tolerance approach during the early stages of the design cycle, we introduce defect-
awareness to Electronic Design Automation (EDA) tools for synthesizing robust netlists that
can withstand delays induced by manufacturing defects and process imperfections. These
defect tolerant designs, which are generated using a modified design (RTL2GDS) approach,
have intelligently chosen timing buffers that can tolerate delay variations introduced during
manufacturing, thereby introducing greater resilience to process variation and defectivity and
ensuring correct circuit operation at the target design frequency. Furthermore, we present
an evolutionary algorithm-based method to implement a multi-objective optimization of
design goals, which improves robustness of the design while minimizing the impact on power,
performance and area (PPA) of the design. This optimization method yields a pareto-optimal
front for the designer to select among a set of robust designs that seamlessly integrates defect
tolerance alongside PPA in the design space exploration, toward improving yield without
compromising the target design characteristics
Role of Importin and Ran in Nuclear Import of Histones
No full textHistones H2A, H2B, H3, and H4 are called the core histones and two copies of H2A-H2B dimers
and a copy of (H3-H4)2 tetramer make up the histone octamer. Histone proteins are important to
compact the genomic DNA. Like most proteins, histones are transcribed in the cytoplasm and need
to be imported into the nucleoplasm where they function. Import of cargo involves Importins, and
Rans. Importins transport cargo from the cytoplasm to the nucleus. When this binary complex
reaches the nucleus, it binds with RanGTP and this causes the release of cargo. It is not precisely
known how Importins and Rans import histones. The work of Padavannil et al. (2019) suggests
that the Importin and Ran import histones in a non-canonical way into the nucleus. When nuclear
import does not function correctly, it leads to various cancers and developmental disorders,
highlighting a need to understand the nuclear transport processes. Here, we aim to study these
proteins and uncover the mechanism behind the nuclear transport of H2A-H2B using hydrogen-
deuterium exchange mass spectrometry. We find that addition of Ran destabilizes two of the H2A-
H2B-binding surfaces on Imp9 and stabilizes one interface. This indicates that the N-terminal heat
repeats and acidic loop of Imp9 are responsible for the formation of the unconventional ternary
complex containing Imp9, H2A-H2B, and Ran
Catalytic Imine C–H Alkylation Methods and Novel Three-component Paths to Allylic Amines
No full textThe thesis describes development of C–H alkylation of imine-type compounds and three-
component assembly of allylic amines. First, a general and efficient method of C–H alkylation of
formaldoximes was developed. The protocol unifies light-induced hybrid palladium radical
chemistry with oxidative properties of palladium. As a result, this protocol allows for coupling of
primary, secondary and tertiary alkyl bromides or iodides with variety of terminal oximes under
very mild conditions. Second, the logic was further translated onto glyoxylate-derived
hydrazones, achieving C–H alkylation of the latter. In addition to alkyl halides, the method can
also engage redox-active esters. Mildness of the method, as well as mechanistic features enabled
synthesis of otherwise hard-to-access E isomers, and to approach unusual heterocycles. Next, a
protocol for homologative three-component synthesis of allylic amines was developed. Merging
of the light-induced alkyl-Heck reaction with the classical Tsuji-Trost chemistry enabled rapid
access to allylic amines of various structures. Method also features potential for the
stereoselective transformations
Active, Flexible Circuit Based on Indium-gallium-zinc-oxide Thin-film Transistors to Improve the Spatiotemporal Resolution of Neural Implants
No full textNeural interfaces have become an important tool in studying and treating neural disorders and
diseases. Due to the great interest in understanding the behavior of the nervous system, neural
interfaces have been evolving toward flexible and small devices with a high density of electrodes
to enhance selectivity, electrical performance, and chronic implantation. However, these
characteristics are still limited by the harsh environment of the body, the size of the electrodes,
and the number of individual wires that connect every single electrode to a pulse generator or
application-specific integrated circuit. The integration of soft and flexible polymers as mechanical
substrates minimizes the harsh environmental effects of the body on the neural device and
increases its useful lifetime. Furthermore, the use of active electronic circuits based on thin-film
transistor technology has demonstrated the potential to increase the number of electrodes without
significantly increasing the metallic interconnections. However, meeting the electrical
performance requirements for neural stimulation remains a difficult challenge. In this work, we
explore the use of a two-transistor, one-electrode (2T1E) circuit based on Indium Gallium Zinc
Oxide (InGaZnO4 or IGZO) thin-film transistors (TFTs) using a softening polymer as a mechanical
substrate for the development of a high-count electrode array for neural stimulation. The design,
microfabrication, and electrical performance of the 2T1E circuit and the IGZO TFTs are presented.
Additionally, the electrical resilience, stability, and frequency response of the active device are
discussed and evaluated. Moreover, electrochemical measurements are presented to determine the
potential of the 2T1E circuit to achieve the electrical performance required for neural stimulation.
In this work, the ability to control the On/Off state of an electrode and send biphasic stimulation
pulses through the IGZO channel was demonstrated. Overall, this work can pave the way for a
new generation of high-channel-count electrode arrays with a high spatiotemporal resolution to
enable new paradigms for neural stimulation in harsh, aggressive biological environments
Iraqi Women’s War Memoirs: From Traumatic Experiences Towards Healing and Empowerment
No full textThe literary Iraqi war narrative replicates the trauma and oppression that Iraqi people have
suffered across three decades of war. Many scholars have won acclaim by writing about the
political situation and war in Iraq, conveying the country’s wounds to the world. However,
academic literary research about the effect of trauma on individuals is limited because most
scholars emphasize catastrophic events occurring during the recurring periods of conflict and
instability. While Iraqi literature has historically highlighted more work written by men than
women, this study focuses on the few Iraqi women who have written about their real traumatic
personal experiences and the impact on society. This dissertation examines non-fictional war
memoirs of three contemporary Iraqi women: Haifa Zangana’s Dreaming of Baghdad (2009),
Zainab Salbi’s Between Two Worlds (2006) and Nadia Murad’s The Last Girl (2017). The study
explores textual representation of traumatic experiences of Iraqi women and their stylistic
narrative techniques in presenting political oppression. The thesis uses trauma theory by Judith
Herman, Sigmund Freud, and Cathy Carruth to offer an interpretative dynamic about shattered
lives of these three Iraqi memoirists. These Iraqi women experienced hardship and have utilized
their writing as a means of catharsis and healing their despair. In response to the trauma suffered
after decades of war in Iraq, I have focused on the cathartic effect of writing to assist in healing
and to serve as a means of resistance after reading and analyzing the literary work of these Iraqi
women war memoirists. Despite their political oppression, these Iraqi women war memoirists
endured harsh periods of war and have become active agents of change through writing and have
carved out space and opportunities for crafting a new identity rooted in activism
Global Stability of SIR Model With Heterogeneous Transmission Rate Modeled by the Preisach Operator
No full textIn recent years, classical epidemic models, which assume stationary behavior of individuals,
have been extended to include an adaptive heterogeneous response of the population to
the current state of the epidemic. However, it is widely accepted that human behavior can
exhibit history dependence as a consequence of learned experiences. This history-dependence
is similar to hysteresis effects that have been well-studied in control theory. To illustrate the
importance of history-dependence for epidemic theory, we study the dynamics of a variant
of the SIR model where individuals exhibit lazy-switch responses to prevalence dynamics.
The resulting model, which includes the Preisach hysteresis operator, possesses a continuum
of endemic equilibrium states characterized by different proportions of susceptible, infected,
and recovered populations. We discuss the stability properties of the endemic equilibrium set
and relate them to the degree of heterogeneity of the adaptive response. In particular, our
results suggest that heterogeneity promotes the convergence of the epidemic trajectory to an
equilibrium state. Heterogeneity can be achieved by selective intervention policies targeting
specific population groups. On the other hand, heterogeneous responses can lead to a higher
peak of infection during the epidemic and a higher prevalence at the endemic equilibrium after
the epidemic. These results support the argument that public health responses during the
emergence of a new disease have long-term consequences for subsequent management efforts.
The main contribution of this work is a new method of global stability analysis, which uses a
family of Lyapunov functions corresponding to different branches of the hysteresis operator.
It is well known that instability can result from switching from one flow to another even
though each flow is stable (if the flows have different Lyapunov functions). We provide
sufficient conditions for the convergence of trajectories to the equilibrium set for switched
systems with the Preisach hysteresis operator
0.3 THz CMOS Transceiver Pixels for Reflection Mode Active Imaging
No full textElectromagnetic waves at frequencies ranging from 0.1 to 10THz, commonly referred to as THz
waves have a wide variety of medical, security and industrial imaging applications. However,
generation and detection of signals at these frequencies are quite challenging. The complementary
metal-oxide semiconductor (CMOS) technology which is widely used in most of the modern
consumer electronic devices is an affordable means for generation and detection of THz signals.
Near-millimeter-wave and terahertz imagers are expected to complement visible light, IR, Radar
and Light Detection and Ranging (LiDAR) imaging by providing a unique combination of angular
resolution and a capability to image in visibly impaired conditions such as fog, rain and dust as
well as for imaging through other materials. This research aims at the design of concurrent
transceiver pixels operating at frequencies around 300GHz for reflection mode active imaging
using a CMOS process technology.
A 7-element array of 287-GHz CMOS transceiver pixels with pixel area smaller than (λ/2)2 housed
in a QFN package is demonstrated. Each pixel concurrently performs transmission and coherent
detection using a push-push VCO, that functions as a 287-GHz transmitter, a 143-GHz LO, and a
sub-harmonic mixer at the same time. An effective isotropic radiated power (EIRP) of −2.5dBm
and sensitivity of −88dBm for 1-kHz noise bandwidth are achieved. Link budget analyses suggest
that it should be possible to perform reflection-mode active imaging at 10 m using the array, and
a reflector with a diameter of 15-cm and a simulated near-field gain of 44.6dB. The packaged array
exhibits a 2.5-dB higher EIRP and a 3-dB lower noise figure than the array without QFN packaging
due to the antenna performance enhancement. This demonstrates that it is possible to package 300-
GHz integrated circuits with an on-chip patch antenna using a low-cost technique.
Lens-less short-range reflection-mode imaging through cardboard is demonstrated at 275GHz
using a pair of concurrent CMOS transceiver pixels separated by ~5mm on a PCB. An isolation
study employing EM simulations is performed to quantify the unwanted coupling. This is first
such demonstration at frequencies above 100GHz. The separation between the imaged object and
pixels is ~1cm and the operation at 275GHz allows the lateral resolution to be reduced to ~2mm
due to a smaller wavelength. This pixel achieves an EIRP of -18.9dBm and a double-sided noise
figure (NFDSB) of ~51dB in an area of 0.45×0.49 mm2.
An 1x3 array of 296-GHz CMOS concurrent transceiver pixels incorporating circuits for baseband
signal extraction in addition to the RF section in an area of (λ/2)2 is demonstrated. The EIRP of
array is ~-6dBm and NFDSB is ~48dB. An E-shaped patch antenna to broaden the antenna
bandwidth is used. Using a pair of these arrays, lens-less short-range reflection-mode imaging of
a target ~1cm away through a cardboard is demonstrated. More importantly, use of the arrays
improves isolation between the pair by ~10 dB to ~70 dB compared to that when single pixels are
used. This work points to a path for incorporation of millimeter and sub-millimeter wave imaging
capabilities in a handheld device
Ergodic Properties of Generalized Billiards
No full textWe consider the generalization of the classical billiard map via different reflection laws. We
study several dynamical properties of the resulting dynamical systems with the emphasis on
the ergodic properties of the dynamic