Modern day digital systems employ frequency
synthesizers to provide a common clock to the system.
They are undergoing large scale integration due to which, mitigation
of the effect of noise on power supply has become a major design consideration
in clocking circuits. Rapid scaling of CMOS technology mandates the
design...
This dissertation presents an incremental analog-to-digital converter (ADC) with digital digital-to-analog converter (DAC) mismatch correction. A theoretical time-domain analysis technique was developed to predict the noise performance of the incremental ADC, and a new optimization technique was proposed to minimize the output noise.
In the calibration mode, the incremental ADC...
The objective of this thesis is to provide an initial demonstration of two-terminal and three-terminal electronic devices employing amorphous multi-component metallic film
(AMMF) electrodes. Such a demonstration is successfully achieved in the fabrication of metal-insulator-metal (MIM) diode and hot electron transistor (HETs) structures employing ZrCuAlNi AMMF electrodes. The ultra-smooth surface...
A relatively new model of error control is the limited magnitude error over high radix channels. In this error model, the error magnitude does not exceed a certain limit known beforehand. In this dissertation, we study systematic error control codes for common channels under the assumption that the maximum error...
This paper provides a measurement-based performance evaluation of the Optimized Link State Routing (OLSR) protocol. Two versions of OLSR, OLSR-ETX and OLSR-ETT, are implemented and evaluated on a mesh network that we built from off-the-shelf commercial components. OLSR-ETX uses the Expected Transmission Count (ETX) metric whereas, OLSR-ETT uses the Expected...
Various applications like wireless UWB communication, fast data acquisition systems and digital storage oscilloscopes needs ADCs with instantaneous input signal bandwidth from 0.1-40 GigaHertz range with 6-10 bits of resolution -- a challenging task and an impressive goal to achieve. Flash ADCs have been conventionally employed to achieve these goals...
Work on individually constructed devices has demonstrated that nanowires (NWs) offer great promise for applications such as sensing and optoelectronics. Despite this work, reliable large scale alignment and integration of these individual nanostructures into a lithographically defined process remains a challenge.
Dielectrophoresis (DEP) is a promising alignment method in which...
In recent years quantum random walks have garnered much interest among quantum information researchers. Part of the reason is the prospect that many hard problems can be solved efficiently by employing algorithms based on quantum random walks, in the same way that classical random walks have played a central role...
Magnetically programmable surface acoustic wave (MP SAW) devices were designed, fabricated and characterized in this thesis using integrated giant magnetoresistive (GMR) bits with interdigital reflectors. This provides a proof of concept of a novel storage element on radio frequency identification tags. Interdigital transducers (IDTs) on a piezoelectric substrate are used...
This thesis presents two new approaches for the broadband, time-domain modeling of lossy transmission lines. Each approach is based on an alternative derivation of delay extraction in order to separate the line's linear phase from its
attenuation and dispersion. Augmentation networks represent the derived attenuation networks as rational function approximations....
In wireless sensor network applications, low-power operation of the wireless receiver is critical. To address this need an ultra-low power Binary Frequency Shift Keying (BFSK) receiver using the super-regenerative architecture is developed.
A prototype receiver is built and tested for operation in the 900 MHz ISM band. Lab measurements show...
Error correction codes (ECCs) have been widely used in communication systems and storage devices. Nowadays, the rapid development of integrated circuit technologies makes feasible the implementation of powerful ECCs such as turbo code and low-density parity-check (LDPC) code. However, these high-performance codes require complex decoding algorithms, resulting in large hardware...
This research explores the viability and effectiveness of using an inertial navigation system (INS) to control a beamforming array of microstrip patch antennas with the aim of reducing users' exposure to electromagnetic radiation. The system reduces radiated power directed toward a cellular phone user to below 10% of the total...
Recent advances in wireless technologies have helped the proliferation of wireless devices, ranging from hand-held devices such as cellular phones to more powerful mobile computing platforms as such laptops [1]. Along with that, the end users’
applications running on these devices, ranging from text message to multimedia applications such as...
Multiple-input multiple-output wireless systems promise significant capacity gain
and/or diversity gain over single antenna systems. If channel state information (CSI)
is available at both the transmitter and the receiver, the performance can be further
improved. In this thesis, first, we study binary index feedback problem in beamforming
systems when the...
Visual information presented in diagrams promotes information processing both in an individual and in collaborative work. Previous literature has identified the role of diagrams in
understanding information processing in a variety of disciplines. In software engineering, diagrams are a prevalent method involved in process development: diagrams are used for system...
Amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) constitute the central theme of this thesis. Within this theme, three primary areas of focus are pursued.
The first focus is the realization of a transparent three-stage ring oscillator with buffered output and an output frequency in the megahertz range. This leads to...
Medical imaging technologies play a vital role in early diagnosis of disease by providing internal images of the human body to medical professionals. Computed Tomography (CT) is currently the most commonly used medical imaging technology because it is easy to use, detectors and scanners are constantly improving, and more importantly,...
Engineering students spend a significant amount of their undergraduate careers focused on technical theory and practice. This intensive student prepares them for their technical challenges in the future. This training is so intense that often the more 'soft skills' such as communication, leadership, design, and troubleshooting are left out or...
This thesis describes the transport properties observed in thermally treated graphite oxide (GO), which holds promise as an economical route to obtaining graphene. Graphene is a material consisting of a single atomic plane of carbon atoms and was first isolated as recently as 2004. Several isolation techniques have been investigated,...
Monte-Carlo planning algorithms such as UCT make decisions at each step by
intelligently expanding a single search tree given the available time and then
selecting the best root action. Recent work has provided evidence that it can be
advantageous to instead construct an ensemble of search trees and make a...
Recent developments in computing technology have generated a demand for more streamlined and effective test systems. By replacing traditional in-chassis wired interconnects with a broadcast wireless system, fault detection and error susceptibility will drastically improve, input/output capabilities will expand, and routing complexity will decrease. Ultra-wideband impulse radio's (UWB-IR) characteristic multipath-immunity...
Continual growth of the world's energy consumption and the demand for long-term clean renewable energy resources has led to the development of ocean-based wave energy technologies. Emerging technologies are advancing potential solutions to the complex problem of energy generation in the harsh and corrosive ocean environment. To develop these technologies,...
While there are many ways to evaluate a user interface design, the user's mental workload and situation awareness (SA) are particularly important considerations in the supervisory control of safety-critical systems. Typically, operators of these systems must monitor high-volume, time-sensitive status information. Interface design for this domain can be challenging and...
With increasing transistor operating frequencies, interconnects and passive devices are becoming performance limiters in integrated circuit (IC) designs. To combat this, the interconnect layers above the active silicon are trending toward low-κ dielectrics and Cu metallization. The use of these new materials has popularized chemical mechanical polishing (CMP) to planarize...
One of the key challenges in downlink multiuser multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is the mitigation of the multi-access interference when different users share the same subcarriers. In this work, the block diagonalization (BD) algorithm for inter-user interference pre-cancelation is extended to MIMO-OFDM systems. However, in...
Asymmetric tensor fields are useful for understanding fluid flow and solid deformation. They present new challenges, however, for traditional tensor field visualization techniques such as hyperstreamline placement and glyph packing. This is because the physical behavior of tensors inside real domains where eigenvalues are real is fundamentally different from the...
3D object recognition is a very difficult and important problem in computer vision, arising in a wide range of applications. Typically in 3D object recognition, interest points are extracted from images and then matched. A shortcoming of this approach is that points only carry local visual information. Therefore, there
could...
In text classification, labeling features is often less time consuming than labeling entire documents. In situations where very little labeled training data is available, feature relevance feedback has the potential to dramatically increase classification performance. We review previous work on incorporating feature relevance feedback in the form of labeled features...
This dissertation explores algorithms for learning ranking functions to efficiently solve search problems, with application to automated planning. Specifically, we consider the frameworks of beam search, greedy search, and randomized search, which all aim to maintain tractability at the cost of not guaranteeing completeness nor optimality. Our learning objective for...
High speed and high resolution analog-to-digital converter is a key building block for broadband wireless communications, high definition video applications, medical images and so on. By leveraging the down scaling of the latest CMOS technology and the noise shaping properties, delta-sigma (ΔΣ) ADCs are able to achieve wide-band operation and...
Trends in wireless networks are increasingly pointing towards a future with multi-hop
networks deployed in multi-channel environments. In this thesis, we present the design
for iMAC—a protocol targeted at medium access control in such environments. iMAC
uses control packets on a common control channel to faciliate a three-way handshake
between...
Pulsed ultra-wideband (UWB) radio uses extremely short pulses to transmit information. Such pulses provide very fine timing information, which has led to technological advances in high-precision localization. This thesis investigates UWB localization strategies with a focus on receiver synchronization algorithms for time-difference-of-arrival localization to achieve centimeter accuracies in a 3-dimensional...
This thesis describes circuit architectures and techniques that facilitate the
automatic synthesis and fabrication of analog-to-digital converters (ADCs). Since
automated synthesis already exists for digital circuits and is part of the digital
circuit design flow, this work demonstrates the feasibility of ADC synthesis with
little or no modification to presently...
As interest grows in developing devices to harvest energy from ocean waves, tidal currents, and offshore wind, concerns over possible environmental effects from such devices also grow. One such concern is over the induced electric fields and the generated magnetic fields from generators and their associated submarine power cables in...
The term Citizen Science refers to scientific research in which volunteers from the community participate in scientific studies as field assistants. Since citizen scientists can collect data cheaply, they enable research to be performed at much larger spatial and temporal scales than trained scientists can cover. Species distribution modeling which...
Advances in process technologies have led to the development of low-power high speed digital signal processing blocks that occupy small areas. These advances are critical in the development of portable electronic devices with small feature size and long battery life. However, the design of analog and mixed-signal
building blocks, especially...
With the recent interest in increasing the penetration of renewable energy sources onto the power grid, there has been an unprecedented rapid deployment of wind generation, especially in the US Pacific Northwest. While wind farm developers have continued to expand their operations, power system operators are left to deal with...
Delta-sigma analog-to-digital converters (ADCs) are suitable for many applications due to several advantages such as relaxed anti-aliasing filter, high signal-to noise and distortion ratio (SNDR) and most important of all, reduced sensitivity to
analog imperfections.This thesis introduces several structures to overcome loop imperfections and stability issues in delta-sigma modulators. First,...
Keeping FOSS developers motivated is a challenging problem, and their motivation levels can affect the team's productivity and satisfaction, leading to higher or lower productivity. Using reputation systems as a motivator has become the de-facto standard for many online communities, rewarding user's activity through badges of honor or achievement levels....
Powerline communication (PLC), is becoming a more commonplace method for data transmission, however it is still a very new medium for data transmission, and international standards for powerline communication are still in the process of being developed and established. PLC can provide a means of simplifying the device connectivity to...
The enormous success of wireless technology has recently led to an explosive demand for, and hence a shortage of, bandwidth resources. This expected shortage problem is reported to be primarily due to the inefficient, static nature of current spectrum allocation methods. As an initial step towards solving this shortage problem,...
Ocean wave energy shows great potential as a developing form of renewable energy. However, challenges arise in maturing this technology to achieve cost-effective energy conversion. Development and testing of wave energy converters can be problematic due to the harsh environment in which they are operated. To promote development of this...
Phase-Locked Loops (PLLs) are essential building blocks in many communication systems. Designing high performance analog PLLs in the presence of technology imposed constraints such as leakage, poor analog transistor behavior, process variability, and low supply voltage is a challenging task. To overcome these drawbacks, digital PLLs (DPLLs) have recently emerged...
The gradient of a velocity vector field is an asymmetric tensor field which can provide critical insight that is difficult to infer from traditional trajectory-based vector field visualization techniques. I describe the structures in the eigenvalue and eigenvector fields of the gradient tensor and how these structures can be used...
Ultra-wideband (UWB) radio has become an attractive alternative for wireless communications due to the robustness to multipath fading, low power transmission, mostly-digital implementation, and low cost. Furthermore, short-range, high data-rates applications are possible with UWB radios due to the wide spectral
allocations at 3.1 - 10.6 GHz.
This thesis presents...
Supply noise is one of the major considerations in almost all analog building blocks. In the past, adequate supply rejection is usually achieved with circuit isolation or excess capacitive coupling. However, this brute force method requires large silicon area and degrades feedback bandwidth. In this study, a method of enhancing...
As more features are being integrated into mobile platforms, the demand for
long battery life during standby mode has been increasing. Light load efficiency
becomes one of essential features in today's DC-DC converter. The most effective
method to improve light load efficiency is to operate the DC-DC converter under
pulse-frequency-modulation...
We investigate a number of techniques for increasing throughput and quality of media applications over wireless networks. A typical media communication application such as video streaming imposes strict requirements on the delay and throughout of its packets, which unfortunately, cannot be guaranteed by the underlying wireless network due inherently to...
This study introduces a layered model for rendering human teeth. Human teeth exhibit complex light interaction due to their layered structure. While the lighting responses of teeth have been studied in the dental industry for the production of realistic looking dentures, to our knowledge this is the first study of...