Hybrid automatic repeat request (HARQ) schemes combine packet retransmission with forward error correction to ensure a reliable communications. In multiple-input multiple output (MIMO) systems, interference cancellation (IC) detection is widely used where the detection and cancellation steps of the simultaneously transmitted data streams occur. In principle, the signal stream estimated...
This thesis focuses on two aspects of transparent electronics, SnO₂ transparent thin-film transistors (TTFTs) and transparent circuits. Both depletion- and enhancement-mode SnO₂ TTFTs are realized. The maximum effective mobility for the depletion- and enhancement-mode devices are 2 cm²V⁻¹s⁻¹ and 0.8 cm²V⁻¹s⁻¹, respectively. A variety of techniques to decrease the carrier...
People like going on trips with friends and tend to plan their trips well in advance to have the best possible experience of a destination and get the most out of the places they visit and/or the activities they plan to partake in. Right now, the Internet provides a wealth...
The project team surveyed and interviewed forty identified experts within the diverse tsunami community. The survey revealed that this community is a sophisticated user of Internet search engines and tools and is very familiar with existing information. The sites mentioned most frequently as being helpful were those of the National...
Emergence of highly accurate Convolutional Neural Networks (CNNs) with the capability to process large datasets, has led to their popularity in many applications, including safety/security-sensitive (e.g. disease recognition, self-driving cars). Despite the high accuracy of convolutional neural networks, they have been found to be susceptible to adversarial noise added to...
Ensuring correctness of real-world software applications is a challenging task. Testing can be used to find many bugs, but is typically not sufficient for proving correctness or even eliminating entire classes of bugs. However, formal proof and verification techniques tend to be very heavy weight and are simply not available...
We consider the problem of tactical assault planning in real-time strategy games where a team of friendly agents must launch an assault on an enemy. This problem offers many challenges including a highly dynamic and uncertain environment, multiple agents, durative actions, numeric attributes, and different optimization objectives. While the dynamics...
In Radio Frequency Integrated Circuits (RFIC) or high frequency digital
ICs, there is a demand to probe the internal nodes for testing. The ultra low
capacitance RFIC probe presented in his work is a flexible tool for these
applications. The probe utilizes the coupling between a tungsten needle and the...
Silicon photonics has become the most promising platform for future large-scale optical interconnect and optical computing systems due to its inherent CMOS compatibility, which brings exclusive advantages in bandwidth density, energy efficiency, and cost effectiveness. Parallel optical interconnects based on photonic integrated circuits (PICs) have the capacity to meet the...
This thesis presents a low-energy application specific digital controller for a battery-free 2.4 GHz wireless sensor network (WSN) node. The digital controller has been designed and fabricated in a standard 0.13 μm CMOS and implements a simple protocol for WSNs. Techniques such as supply voltage reduction and power gating have...
Low energy design techniques for digital circuits are examined to determine their suitability for use in a digital logic controller for wireless sensor network nodes. Transistor level simulations are used to evaluate the techniques and those demonstrating an energy reduction are used to implement a digital logic controller. The digital...
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...
As the number of autonomous data collection applications keep increasing, the demand for wireless sensor networks (WSNs) has seen explosive growth. In this dissertation, an ultra-low-energy WSN transmitter is developed to reduce the energy consumption of sensor nodes in WSNs. With an ultra-low-energy transceiver, it is possible to eliminate the...
Indoor localization systems have a variety of applications such as tracking of assets, indoor robot navigation, and monitoring of people (e.g. patients) in hospitals or at home. Global positioning system (GPS) offers location accuracy of several meters and is mainly used for outdoor location-based applications as its accuracy degrades significantly...
This paper proposes a novel means of using analog correlators to improve upon existing Ultra-Wideband receiver architectures. Current architectures aim for an all-digital design for the sake of ease of implementation and conceptual simplicity. This causes some notable design challenges including an ultra-high sampling rate, and difficulty capturing multipath energy....
Impulse-radio ultra-wide-band (IR-UWB) signaling is a promising technique
for high-speed, short-range relay communications networks. Depending on how
the relay node retransmits the signal, there are two main relay schemes: conventional
one-directional (one-way) relay model, and bi-directional (two-way) relay
model. In bi-directional relay communications, wireless network coding (WNC),
also called physical-layer...
The ability to extract uncertainties from predictions is crucial for the adoption of deep learning systems to safety-critical applications. Uncertainty estimates can be used as a failure signal, which is necessary for automating complex tasks where safety is a concern. Furthermore, current deep learning systems do not provide uncertainty estimates,...
End users' programs are fraught with errors, costing companies millions of dollars. One reason may be that researchers and tool designers have not yet focused on end-user debugging strategies. To investigate this possibility, this dissertation presents eight empirical studies and a new strategy-based end-user debugging tool for Excel, called StratCel....
A bad software development process leads to wasted effort and inferior products. In order to improve a software process, it must be first understood. In this work I focus on understanding software processes.
The first process we seek to understand is Continuous Integration (CI). CI systems automate the compilation, building,...
Enabled by a rich ecosystem of Machine Learning (ML) libraries, programming using learned models, i.e., Software-2.0, has gained substantial adoption. However, we do not know what challenges developers encounter when they use ML libraries. With this knowledge gap, researchers miss opportunities to contribute to new research directions, tool builders do...
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...
Software maintenance accounts for a large portion of the software development cost, particularly the process of updating programs either to adapt for requirement change or to enhance design or efficiency. Currently, program updates are generally performed manually by programmers using text editors. This is an unreliable
method because syntax and...
A Mobile Ad-hoc NETwork (MANET) is collection of wireless mobile nodes without a network infrastructure or centralized administration. Although MANETs can be used in many applications, such as mobile Internet, military communication, and disaster relief networks, a number of challenges remain. These include routing, medium access control, security, scalability, energy...
Scientists and engineers have to analyze and query multiple large databases. Analysis over databases created by phasor measurement units can provide insight into the health of the grid, thereby improving control over operations. Realizing this data-driven control, however, requires validating, processing and storing massive amounts of PMU data efficiently, which...
Continuous integration (CI) systems automate the compilation, building, and testing of software. Despite CI rising as a big success story in automated software engineering, it has received almost no attention from the research community. For example, how widely is CI used in practice, and what are some costs and benefits...
Over the last decade, wind penetration in the Pacific Northwest has increased rapidly. The variable nature of this massive new resource has increased stress on the hydropower resource to the point where system limits are currently being reached. In order to cultivate continued growth of the wind energy industry both...
Streaming media and interactive television viewing experiences are becoming more commonplace with the introduction of services such as Netflix Streaming, the Apple TV, and Google TV aided by the increase adoption of broadband internet. As these services make their way into the living room, and developers struggle to accommodate more...
Apple launched their first “tap-and-pay” mobile payment solution called “ApplePay” in October 2014 in the United States. Quickly catching up with the popularity of Apple Pay, Google launched their own mobile “tap-and-pay” paymentsolution called “Android Pay”. Both the companies claim that their tap-and-paysolutions are more convenient and more secure than...
Appropriate representations of variational software simplify the analysis of their properties.This thesis proposes tailored representations of two kinds variational softwares: difference files of merge commits in Git and feature models. For the former, we use the Choice Edit Model, which is based on the choice calculus, to represent changes introduced...
In the field of Human-Computer Interaction, provenance refers to the complete history and genealogy of a document. Provenance can be useful in identifying related resources, such as different versions of the same document or resources used in the creation of a new document. Though methods of provenance collection and applications...
Air traffic flow management over the U.S. airpsace is a difficult problem. Current management approaches lead to hundreds of thousands of hours of delay, costing billions of dollars annually. Weather and airport conditions may instigate this delay, but routing decisions balancing delay with congestion contribute significantly to the propagation of...
Desktop widget engines have emerged as an alternative for completing simple tasks without the need for a full-blown application or constant user interaction. Widgets can simply display data in a compact and visually appealing manner (such as stock tickers, weather forecasts, and news notifications), or go so far as to...
Real time indoor positioning awareness systems aim to add localization capabilities to upcoming wireless technologies that are quickly becoming an important feature for indoor environment. RF-based impulse-radio ultra-wideband (IR-UWB) is a promising technology for in-door positioning systems due to obstacle penetration capabilities, immunity to multi-path and fading, and high resolution....
When the term renewable energy is mentioned in a conversation, wind, solar, and hydro energy typically come to mind. However, there is one major resource that has remained mostly untapped: wave energy. Wind and solar power technologies are well established around the world but they cannot generate electricity all the...
In networked control systems (NCS) information or packets usually flow from a
sensor or a set of sensors to a remotely located controller. Then the controller
processes the received information and sends a series of control commands to the
actuators through a communication network which could be either wireless or...
With the development of technologies in genome sequencing and variant detection, a huge number of variants are detected. To further analyze the variants, it requires an efficient tool to annotate the functional effect of variants. This project managed to develop an efficient program to annotate the functional effect of variants...
Over the last two decades, satisfiability and satisfiability-modulo theory (SAT/SMT) solvers have grown powerful enough to be general purpose reasoning engines throughout software engineering and computer science. However, most practical use cases of SAT/SMT solvers require not just solving a single SAT/SMT problem, but solving sets of related SAT/SMT problems....
The study of variational typing originated from the problem of type inference for variational programs, which encode numerous different but related plain programs. In this dissertation, I present a sound and complete type inference algorithm for inferring types of all plain programs encoded in variational programs. The proposed algorithm runs...
Information Foraging Theory (IFT) has successfully explained how people seek information in various domains, in turn, informing the design of several tools and information-intensive environments. However, prior research has not explored foraging in the presence of several, very similar variants of the same artifact. Such variants are commonplace in several...
Software history and version control systems (VCS) are an important source of information for developers. This entails the need for a principled understanding of developers’ information seeking in VCS, both for improving existing tools as well as understanding requirements for new tools. However, it is only recently that researchers have...
With an increasing number of wireless applications at microwave frequencies, the frequency spectrum is becoming quite crowded. Due to this congestion, the current state of technology is leading towards upper microwave and millimeter wave spectra as they also offer other distinct advantages such as larger bandwidth and smaller component footprint....
This thesis consists of two major components. The first part is concerned with video object instance segmentation (VOS), which is the task of assigning per-pixel labels perframe of a video sequence to indicate foreground object instance membership, given the first frame ground truth mask. VOS has myriad applications, from video...
This report presents an efficient method for semi-supervised video object segmentation – the problem of identifying foreground pixels occupied by a target object. The target is specified by the ground-truth mask in the first video frame. While the state of the art achieves a segmentation accuracy greater than 80%, it...
With the increase in demand for streaming media capabilities across the Internet, the focus has shifted from traditional client-server to peer-to-peer approaches. Content Distribution Networks (CDNs) have also recently moved from web acceleration to media streaming. P2P CDNs can be used both as a delivery mechanism and as an independent...
While individual portfolio diversity analysis is a well-studied problem in visualization, the visual analysis of individual or groups of portfolios, over time, has received little attention. Such analysis, however, is important to researchers who are interested in better understanding portfolio management behavior of experts as well as novices. We conducted...
Learning to recognize objects is a fundamental and essential step in human perception and understanding of the world. Accordingly, research of object discovery across diverse modalities plays a pivotal role in the context of computer vision. This field not only contributes significantly to enhancing our understanding of visual information but...
Cold air pools are spatiotemporal phenomena that occur when cold air from higher elevations roll down the slope to accumulate in lower elevations. Behaviors like this lead to microclimate anomalies such as the city of Corvallis (Oregon) experiencing persistent cold weather even on a sunny day. We analyze multivariate temperature...
Transportation infrastructure provides a vital service for the functionality of a
city. The efficient design of road networks poses an interesting topic in computer
science for digital content developers. For civil engineers, the visualization of
analysis results on infrastructure both efficiently and intuitively is crucial. The
following contributions are made...
N-ary relationships, which relate N entities where N is not necessarily two, are omnipresent in real life. In this thesis, we develop a visualization technique for N-ary relationships.
First, we propose a visual metaphor that utilizes vertices and polygons to represent entities and N-ary relationships. Based on this visual metaphor,...
Open Source software gives users the freedom to copy, modify and redistribute source code without legal entanglements. The evolution of these software communities usually depend a lot on how the participating developers and users interact and co-operate with each other. Over the past few years, open source software have become...