In this thesis, we present semantic equivalence rules for an extension of the choice calculus and sound operations for an implementation of variational lists. The choice calculus is a calculus for describing variation and the formula choice calculus is an extension with formulas. We prove semantic equivalence rules for the...
Given k terminal pairs (s₁,t₁),(s₂,t₂),..., (s[subscript k],t[subscript k]) in an edge-weighted graph G, the k Shortest Vertex-Disjoint Paths problem is to find a collection P₁, P₂,..., P[subscript k] of vertex-disjoint paths with minimum total length, where P[subscript i] is an s[subscript i]-to-t[subscript i] path. As a special case of the...
This dissertation presents a phase domain in-loop-bandwidth spread-spectrum clock generation technique. In this proposed technique, a charge-based discrete-time loop filter is proposed to enable the phase domain in-loop-bandwidth spread-spectrum modulation without a delta-sigma modulator or time-to-digital converter. The in-loop-bandwidth modulation technique maximizes the loop bandwidth to improve phase noise suppression...
We model the popular board game of Clue as an MDP and evaluate Monte-Carlo policy rollout in a simulated environment pitting different agents and policies against each other. We describe the choices we made in the representation, along with some of the problems we encountered along the way. We find...
This project is a custom output stage for a two-channel signal source design project at Oregon State. Starting in January, I began leading a team tasked with the development of an arbitrary waveform generator via the CreateIT Collaboratory at OSU. Undergraduate students interview into the CreateIT Collaboratory and are assigned...
As scaling of silicon (Si) based devices approaches fundamental limits, thin film metal-insulator-metal (MIM) tunnel diodes are attracting interest due to their potential for high speed operation. Because operation of these devices is based on tunneling, electrode / interfacial roughness is critical. Recently, it was shown that combining ultra-smooth bottom...
Transparent conductive oxides (TCOs), primarily indium doped tin oxide, have been widely used in numerous fields since decades ago, such as solar cells, displays, OLEDs and ‘smart windows’ etc. Owing to the scarcity of indium, there is a great demand for new alternative materials. Metal/insulator/metal (MIM) diodes are a critical...
The Intel Xeon Phi is a relative newcomer to the scientific computing scene. In the recent years, GPUs have been used extensively for mathematical simulations. The Xeon Phi is Intel’s response to the use of these cards. Like the GPU, it is highly parallelizable but can be programmed like a...
In data-centers, running multiple isolated workloads while getting the most performance out of available hardware is key. For many years Virtual Machines (VMs) have been an enabler, but native containers which offer isolation similar to virtual machines while reducing overhead costs associated with emulating hardware resources have become an increasingly...
Branched covering spaces are a mathematical concept which originates from complex analysis and topology and has found applications in tensor field topology and geometry re-meshing. Given a manifold surface and an N-way rotational symmetry field, a branched covering space is a manifold surface that has an N-to-1 map to the...
Massive MIMO is a promising technique for future 5G communications due to its high spectrum and energy efficiency. To realize its potential performance gain, accurate channel state information at transmitter side (CSIT) is essential. Frequency division duplex (FDD) is widely employed by the most cellular systems today. However, it requires...
Recently, there has been peaked interest in developing high energy producing and optimized power take-off topologies for Wave Energy Converters (WEC). As large as the potential of the oceans may seem, harnessing that energy and effectively converting it to electricity in significant amounts is a challenge. Currently, there are no...
Software Defined Storage is a term for data storage software to manage policy-based provisioning and management of heterogeneous data storage system abstracting underlying hardware. CoprHD is a software defined storage controller and API platform which enables policy-based management and cloud automation of storage resources for block, object and file storage...
This work presents the design and implementation of a low power phased-array receiver frontend at 28 GHz in 65 nm CMOS. The frontend incorporates a low- power low-noise amplifier(LNA) and a passive reflection-type phase shifter (RTPS) capable of providing 360° phase shift with 5-bit phase resolution and low loss variation....
The rapid scaling of network bandwidth and data center throughput has motivated the wide adoption of high speed transceivers. Silicon photonics (Si-Photonic) is one of the most promising techniques to realize tightly integrated optical transceivers for next-generation high speed I O standards. This dissertation focuses on the design techniques of...
The National Conference of State Legislatures NCSL declares that 29 states have
been active in adopting and increasing renewable portfolio standards. Present
renewable portfolio standards require utilities to increase integration of renewable
energy sources such as photovoltaic (PV). The increased penetration of PV systems
is expected to destabilize the power...
Recent opportunities for new hydropower generation in the United States have often been in non-powered dams and run-of-river type flows occurring in low-impact natural areas and unregulated conduits. At the same time, a changing water resource paradigm is challenging some existing generation in drought stricken areas where supply reservoirs behind...
Deep learning has greatly improved visual recognition in recent years. However, recent research has shown that there exist many adversarial examples that can negatively impact the performance of such an architecture. Different from previous perspectives that focus on improving the classifiers to detect the adversarial examples, this work focuses on...
The outsourcing of data storage and related infrastructure to third-party services in the cloud is a trend that has gained considerable momentum in the last decade due to the savings it affords companies in both capital and operational costs. Although encryption can alleviate some of the privacy concerns associated with...
Disaster response robots need to be simultaneously able to survive extreme environment and complete the mission efficiently and robustly. One of the determinants is the performance of the actuators in each joint, which drive the robot to the desired motion accurately. In robotics society, people usually build their robots directly...
The current state of research on gossip techniques for wireless broadcasting is very limited because past research efforts have mostly focused on using gossip techniques for multicast communication. On the other hand, those research efforts that have focused on using gossip techniques for wireless broadcast communications ignore energy efficiency and...
Energy consumption has become a great deal for cloud service providers due to financial as well as environmental concerns. Studies show that cloud servers operate, most of the time, at only between 10% and 50% of their maximal utilizations. These same studies also show that servers that are kept ON...
In the current education environment, many instructors make use of some type of software, such as Visual Studio or a software library like OpenGL, in the classroom. Incorrect setup and configuration on an individual’s own system is a common problem when using these software tools. This thesis explores the difficulty...
Software testing is a very important task during software development and it can be used to improve the quality and reliability of the software system. One potential way to reduce the cost and increase the efficiency of software testing is to generate test data automatically. Search-based approaches successfully generate unit...
Advances in low-power digital integration and microelectro-mechanical systems (MEMS) have paved the way for micro-sensors. These sensors are equipped with data processing capabilities along with sensory circuits. Sensor data are processed on these individual sensors and transmitted to the target (sink). Lowcost integration and small sizes of these sensors have...
An important impact of the genome technology revolution will be the elucidation of mechanisms of cancer pathogenesis, leading to improvements in the diagnosis of cancer and the selection of cancer treatment. Integrated with current well-studied massive knowledge and findings about the role of protein-coding mutations in cancer, demystifying the functional...
Electric grid is a critical cyber-physical infrastructure that serves as lifeline for modern society. With the increasing trend of cyber-attacks, electric grid security has become a significant concern. Electric grid operators are working hard to reduce the risk of these attacks towards the system. Having security metrics for monitoring the...
Diabetes is a pandemic that affects nearly 29.1 million Americans and the fourth leading cause of mortality in the US. Type 1 diabetes is a chronic condition which occurs due to little to no production of insulin by the pancreas. This form of diabetes requires constant monitoring of blood glucose...
Debugging, an integral part of software development, is difficult for end-user programmers, especially in the case of complex programs. The process of isolating errors is time consuming without the help of debugging support provided by the tool. For example, the visual programming tool LondonTube supports creation of custom mobile-cloud-web applications,...
Modern variable speed machine drive (VSMD) systems are used for a variety of purposes including generation, propulsion, pumps and compressors. They employ high switching frequency power electronics to drive the electric machine. The machine is subject to large voltage overshoot if long power cables, are used, called Reflected Wave Phenomena...
The ability to create reproducible cryptographically secure keys from temporal environments (e.g., images) has the potential to be a contributor to effective cryptographic mechanisms. Due to the noisy nature of these environments, achieving this goal in a user friendly fashion is a very challenging task, especially since there exists a...
General-purpose Graphics Processing Units (GPGPUs) have become a critical component in high-performance computing (HPC) systems in executing modern computational workloads. The high thread level parallelism (TLP) and programmable shader cores allow thousands of threads to execute in Parallel. The fast-scaling of GPGPUs have increased the demand for performance optimizations on...
Empirical studies have shown that programmers spend up to one-third of their time navigating through code during debugging. Although researchers have conducted empirical studies to understand programmers’ navigation difficulties and developed tools to address those difficulties, the resulting findings tend to be loosely connected to each other. To address this...
Cognitive radio technology emerges as a promising solution for overcoming shortage and inefficient use of spectrum resources. In cognitive radio networks, secondary users, which are users equipped with cognitive radios, can opportunistically access spectrum assigned to primary users, the spectrum license holders. Although it improves spectrum utilization efficiency, this opportunistic...
The grid company enforces high penalties for the peak power demands of cloud data centers. These high penalties result in high electricity bills that can be avoided by relying on the servers' Uninterruptible Power Supply (UPS) as a source of energy during peak load periods. This thesis proposes a management...
Social media sources such as Twitter represent a massively distributed social sensor over diverse topics ranging from social and political events to entertainment and sports news. However, due to the overwhelming volume of content, it can be difficult to identify novel and significant content within a broad topic in a...
Maintaining the sustainability of the earth’s ecosystems has attracted much attention as these ecosystems are facing more and more pressure from human activities. Machine learning can play an important role in promoting sustainability as a large amount of data is being collected from ecosystems. There are at least three important...
The design of programming tools is slow and costly. To ease this process, we have developed a design pattern catalog aimed at providing guidance about how to design tools for developers. This guidance is grounded in Information Foraging Theory (IFT), which empirical studies have shown to be useful for understanding...
It has been estimated that data traffic from the different mobile devices that range from smartphones to machine-to-machine (M2M) devices will exceed 15.9 exabyte per month by the year 2018. With this immense data growth, the current wireless communication systems suffer from the scarcity of the radio spectrum and eventually...
As the price of broadband access service becomes more affordable, the number of homes with WiFi and public WiFi hotspots in the US are projected to increase significantly in the next few years. However, limited capacity of existing WiFi networks fail to provide adequate bandwidth for densely populated areas. Therefore,...
Magnetic thin films have potential to improve devices such as on-chip inductors, and enable new technologies such as magnetic random access memory (MRAM).
The use of magnetic cores in on-chip inductors is typically limited to applications well under 1 GHz. At higher frequencies, the performance of the magnetic core is...
In wireless communication, channel state information (CSI) is essential for data detection. Fast fading coefficients estimation is important in order to acquire accurate CSI. Kalman filters (KF) are widely used for real time parameter estimation and can be used to estimate the fast fading coefficients of a mobile communication channel....
We demonstrated a sensitive biosensor based on plasmonic metal composite nanostructures. The device can be fabricated and duplicated with ease using a novel nanoprinting technology which allows precise transfer of metal nanostructures without complicated lithography processes. The design featured by its unique material composition and sub-wavelength structures maximizes the exposure...
Despite significant advantages in terms of portability and cost, near-infrared (NIR) gas sensing still remains a great challenge due to its relatively weak overtone absorption from the fundamental vibrational bond absorption at the mid-IR frequency. In this paper, we demonstrated ultra-sensitive NIR gas sensing for carbon dioxide (CO₂) at 1.57...
In this work, we study network coding technique, its relation to random matrices, and their applications to communication systems. The dissertation consists of three main contributions. First, we propose efficient algorithms for data synchronization via a broadcast channel using random network coding. Second, we study the resiliency of network coding...
The design of mobile wireless devices has always focused on reducing power, area, and cost. This dissertation proposes two techniques that are leveraged to save power and area and therefore cost. The first techniques reduces the noise in the receiver and results in a relaxed power requirement. The second technique...
Optical wireless communication (OWC) is an alternative to radio frequency (RF)communication with a signi cantly larger and unregulated spectrum. In OWC systems, optical orthogonal frequency division multiplexing (O-OFDM) with intensity modulation and direct detection (IM/DD) is commonly used. There are two common signal structures in most OWC systems based on...
Spintronics is an emerging field of research wherein the electron spin instead of, or along with, the conventional electron charge may be utilized in developing next generation logic devices. One of the most promising aspects of spintronics is that information transfer may be achieved by spin waves in logic devices,...
Machine learning models for natural language processing have traditionally relied on large numbers of discrete features, built up from atomic categories such as word forms and part-of-speech labels, which are considered completely distinct from each other. Recently however, the advent of dense feature representations coupled with deep learning techniques has...
Incremental ADCs (IADCs) have found wide applications in sensor interface circuitry since, compared to ∆Σ ADCs, they provide low-latency high-accuracy conversion and easy multiplexing among multiple channels. On the other hand, continuous-time ∆Σ ADCs (CTDSM) have been receiving more and more attention as a power-efficient solution in targeting medium to...
Inkjet printing offers a cost effective, highly customizable method for rapid manufacturing of functional devices with minimal material waste. Although this method has been used for a variety of composites, little work has been done in the area of 3D printing magnetic composites. Presented here is a process for inkjet...
We demonstrated a low-cost and high-sensitivity DNA detection method using quantum dot-fullerene based molecular beacons (MBs) and magnetic nanoparticles. The MB tethered magnetic nanoparticles can be well dispersed in analytes for efficient DNA capture and concentrated by an external magnetic field for enhanced fluorescence signal detection. The detection requires only...
Modeling tire-snow interaction is important in designing effective snow tires, which directly affects road safety during wintry weather. Unfortunately, tires have complex tread designs and the physical properties of snow have not been characterized. We employ the Material Point Method (MPM) for simulating a material that mimics the fracturing and...
RNA secondary structure prediction maps a RNA sequence to its secondary structure (set of AU, CG, and GU pairs). It is an important problem in computational biology be-cause such structures reveals crucial information about the RNAs function, which is useful in many applications ranging from noncoding RNA detection to folding...
Recognizing human actions in videos is a long-standing problem in computer vision with a wide range of applications including video surveillance, content retrieval, and sports analysis. This thesis focuses on addressing efficiency and robustness of video classification in unconstrained real-world settings. The thesis work can be broadly divided into four...
CoprHD is an open source software defined storage controller platform. It holds an inventory of all storage devices in the data center and understands their connectivity. It is an operating system for a storage cloud. It is designed with two key goals in mind:
• Make an enterprise or a...
In bioacoustics, automatic animal voice detection and recognition from audio recordings is an emerging topic for animal preservation. Our research focuses on bird bioacoustics, where the goal is to segment bird syllables from the recording and predict the bird species for the syllables. Traditional methods for this task addresses the...
This dissertation focuses on the development of ultra-compact optical devices for free-space modulation. We propose a surface-normal modulator using metallic photonic crystals for free-space optical interconnects. The active control of light intensity is achieved by engineering the Fano resonances in metallic photonic crystals. Both thermo-optic modulation and electro-optic modulation of...
Hop (Humulus lupulus L. var lupulus) is a plant of great cultural significance, used as a medicinal herb for thousands of years, and for flavor and as a preservative in brewing beer. Studies of the medicinal effects of the unique compounds produced by hop have led to interest from the...
Threshold-based time of arrival (TOA) estimation is a technique for high-precision indoor localization. Existing threshold selection methods, such as xed thresh- old and normalized threshold methods, do not consider the signal-to-noise radio (SNR) value at the receiver. This is not desired for high-precision positioning. A proper threshold value depends on...
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...
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...
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...
Graphics hardware in mobile devices has become more powerful, allowing rendering techniques such as ray-cast volume rendering to be done at interactive rates. This increase of performance provides desktop capabilities combined with the portability of a tablet. Volumes can demand a high amount of memory in order to be loaded...