Computer Engineering Commons^™

Automated Scratchpad Mapping And Allocation For Embedded Processors, Yang Gao

Theses and Dissertations

Embedded system-on-chip processors such as the Texas Instruments C66 DSP and the IBM Cell provide the programmer with a software controlled on-chip memory to supplement a traditional but simple two-level cache. By decomposing data sets and their corresponding workload into small subsets that fit within this on-chip memory, the processor can potentially achieve equivalent or better performance, power efficiency, and area efficiency than with its sophisticated cache. However, program controlled on chip memory requires a shift in the responsibility for management and allocation from the hardware to the programmer. Specifically, this requires the explicit mapping of program arrays to specific …

Practical Concurrency Support For Web Service Transactions, Emad Alsuwat

Theses and Dissertations

Traditional database concurrency control methods use locking, timestampordering, and optimistic-ordering to achieve DB consistency. However, these approaches are not suitable for long-running Web Service Compositions (WSCs) due to associated performance degradation. Our hypothesis asserts that, using transactional semantic and ordering information, the execution time of a WSC can be reduced, thus allowing the use of traditional database concurrency control methods while avoiding unacceptable performance degradation. Our solution is based on the following approaches: § We model a WSC as WS-BPEL specification, i.e., a partial order of WS transactions. § We allow some of the WS transactions in the WSC to …

Automatic Loop Tuning And Memory Management For Stencil Computations, Fan Zhang

Theses and Dissertations

The Texas Instruments C66x Digital Signal Processor (DSP) is an embedded processor technology that is targeted at real time signal processing. It is also developed with a high potential to become the new generation of coprocessor technology for high performance embedded computing. Of particular interest is its performance for stencil computations, such as those found in signal processing and computer vision tasks. A stencil is a loop in which the output value is updated at each position of an array by taking a weighted function of its neighbors. Efficiently mapping stencil-based kernels to the C66x device presents two challenges. The …

Benefits Of Video Games In Multidisciplinary Scientific Research, Jeremiah Jeffrey Shepherd

Theses and Dissertations

In recent years, computer-based games have been shown to be effective both as a tool for conducting research in a variety of domains and for research on games itself. In this work, we show that implementing games that have a basis in theory and that are combined with the most recent gaming practices result in effective research tools. We demonstrate this via game implementations for three domains. The first implementation is based on new theories in speech pedagogy, and demonstrates the effectiveness of our approach. The second implementation shows that using a game that simulates therapeutic speech practices can aid …

Gammatone And Mfcc Features In Speaker Recognition, Wison Burgos

Theses and Dissertations

The feature analysis component of an Automated Speaker Recognition (ASR) system plays a crucial role in the overall performance of the system. There are many feature extraction techniques available, but ultimately we want to maximize the performance of these systems. From this point of view, the algorithms developed to compute feature components are analyzed. Current state-of-the-art ASR systems perform quite well in a controlled environment where the speech signal is noise free. The objective of this thesis investigates the results that can be obtained when you combine Mel-Frequency Cepstral Coefficients (MFCC) and Gammatone Frequency Cepstral Coefficients (GFCC) as feature components …

Lost In The Middle Kingdom: Teaching New Languages Using Serious Games And Language Learning Methodologies, Renaldo Justin Doe

Theses and Dissertations

This thesis focuses on the design and development of a serious video game for language learning entitled Lost in the Middle Kingdom. Our game utilizes several language learning methodologies including second language acquisition theory, content-based instruction, and task-based language teaching. This thesis examines previous language learning games and their drawbacks in order to create a more effective experience. Lost in the Middle Kingdom seeks to balance language learning with fun and intuitive gameplay in order to deliver a form of interactive media that is accepted by both the gaming and research communities. Our test data illustrates the strengths and weaknesses …

Vocab4me: A Tool That Provides Vocabulary Recommendations For Publishing Linked Data, Srikar Nadipally

Theses and Dissertations

The web before linked data was a database of html documents. These documents were meant for human consumption and it was hard for machines to make sense of data in html documents. The linked data was introduced with the aim of making the web a global database of data that is machine processable. Linked Data describes a method of publishing structured data so that it can be interlinked and become more useful. Realizing the promise of linked data a lot of people started publishing linked data. But the process of publishing the huge amount of existing data is cumbersome and …

Document Image Analysis Techniques For Handwritten Text Segmentation, Document Image Rectification And Digital Collation, Dhaval Salvi

Theses and Dissertations

Document image analysis comprises all the algorithms and techniques that are utilized to convert an image of a document to a computer readable description. In this work we focus on three such techniques, namely (1) Handwritten text segmentation (2) Document image rectification and (3) Digital Collation.

Offline handwritten text recognition is a very challenging problem. Aside from the large variation of different handwriting styles, neighboring characters within a word are usually connected, and we may need to segment a word into individual characters for accurate character recognition. Many existing methods achieve text segmentation by evaluating the local stroke geometry and …

Ghosts Of The Horseshoe: A Mobilization Of A Critical Interactive, Richard Lee Walker

Theses and Dissertations

Critical Interactives (CIs) are designed to harness the voluntary, reality-bending excitement of discovery as afforded by play, but to do so in the context of rules that mobilize procedural rhetoric to instantiate critical awareness. Critical interactives are not just about improving lives through code or education; rather, they establish a methodology for generating more aesthetic and reflective interactive experiences. To grasp more fully the logic underpinning CIs, we need to understand the powerful nature of interactivity and outline how such interactivity involves a notion of ethics, i.e., a way of living, in and through media practice.

Ghosts of the Horseshoe …

Growth, Fabrication And Characterization Of Cu2Znsn(SXSe1-X)4 Photovoltaic Absorber And Thin-Film Heterojunction Solar Cells, Sandip Das

Theses and Dissertations

Current thin-film solar cell technologies based on CuIn_xGa1_-xSe₂ (CIGS) and CdTe photo-absorber materials use rare and expensive elements, such as In, Te, Ga, and toxic Cd which severely limit the mass production and deployment of these solar cells. Thus, a major research effort is focused toward the development of new photovoltaic (PV) absorber materials comprising of earth-abundant, low-cost, and environmentally benign constituent elements that can support terawatt (TW)-scale PV generation in the near future and be economically sustainable. Cu-based I₂-II-IV-VI₄ quaternary kesterite compound Cu₂ZnSn(S_xSe_1-x)4 (CZTSS_{e …}

Using Genetic Algorithm To Solve Median Problem And Phylogenetic Inference, Nan Gao

Theses and Dissertations

Genome rearrangement analysis has attracted a lot of attentions in phylogenetic com- putation and comparative genomics. Solving the median problems based on various distance definitions has been a focus as it provides the building blocks for maximum parsimony analysis of phylogeny and ancestral genomes. The Median Problem (MP) has been proved to be NP-hard and although there are several exact or heuristic al- gorithms available, these methods all are difficulty to compute distant three genomes containing high evolution events. Such as current approaches, MGR[1] and GRAPPA [2], are restricted on small collections of genomes and low-resolution gene order data of …

Memory Interface Synthesis For Fpga-Based Computing, Zheming Jin

Theses and Dissertations

This dissertation describes a methodology for the generation of a custom memory interface and associated direct memory access (DMA) controller for FPGA-based kernels that have a regular access pattern. The interface provides explicit support for the following features: (1) memory latency hiding, (2) static access scheduling, and (3) data reuse. The target platform is a multi-FPGA platform, the Convey HC-1, which has an advanced memory system that presents the user logic with three critical design challenges: the memory system itself does not perform caching or prefetching, memory operations are arbitrarily reordered, and the memory performance depends on the access order …

Research On Approximate Bayesian Computation, Jiting Xu

Theses and Dissertations

This thesis presents the development of a new numerical algorithm for statistical inference problems that require sampling from distributions which are intractable. We propose to develop our sampling algorithm based on a class of Monte Carlo methods, Approximate Bayesian Computation (ABC), which are specifically designed to deal with this type of likelihood-free inference. ABC has become a fundamental tool for the analysis of complex models when the likelihood function is computationally intractable or challenging to mathematically specify. The central theme of our approach is to enhance the current ABC algorithms by exploiting the structure of the mathematical models via derivative …

An Adaptive Educational Game To Help Students Learn How To Solve Systems Of Linear Equations, Wang Zhang

Theses and Dissertations

Educational games have been proven to be effective in developing problem solving skills in well-defined domain, such as Math and Physics. In this thesis, an educational game called Matrix was developed to foster problem solving skills in the domain of linear algebra, particularly solving a system of linear equations. Matrix is an adaptive educational game that uses intelligent tutoring modules to guide the student's learning process and provide feedback based on the student's performance. These modules are domain module, student module, pedagogical module and presentation module. The domain module contains all the concepts the student needs to learn and an …

The Differential Vector Phase-Locked Loop For Global Navigation Satellite System Signal Tracking, James J. Brewer

Theses and Dissertations

A novel differential vector phase-locked loop (DVPLL) is derived that takes GNSS code-phase and carrier-phase measurements from a base station and uses them to maintain an integer ambiguity resolved quality solution directly in the vector tracking loop of a rover receiver. The only state variables estimated and used to create the replica code and carrier signals from the base station measurements are three position and two clock states for a static test. Closing the individual loops solely through the navigation filter makes this a pure vector method. For short baselines, where differential atmospheric errors are small, the DVPLL can be …

Scalable System Design For Covert Mimo Communications, Jason R. Pennington

Theses and Dissertations

In modern communication systems, bandwidth is a limited commodity. Bandwidth efficient systems are needed to meet the demands of the ever-increasing amount of data that users share. Of particular interest is the U.S. Military, where high-resolution pictures and video are used and shared. In these environments, covert communications are necessary while still providing high data rates. The promise of multi-antenna systems providing higher data rates has been shown on a small scale, but limitations in hardware prevent large systems from being implemented.

Secure And Reliable Wireless Communication Through End-To-End-Based Solution, Hossen Asiful Mustafa

Theses and Dissertations

In the past few decades, network architectures and protocols are often designed to achieve a high throughput and a low latency. Security was rarely considered during the initial design phases. As a result, many network systems are insecure by design. Once they are widely deployed, the inherent vulnerabilities may be difficult to eliminate due to the prohibitive update cost. In this dissertation, we examine such types of vulnerabilities in various networks and design end-to-end-based solutions that allow end systems to address such loopholes.

The end-to-end argument was originally proposed to let end hosts implement application-specific functions rather than letting intermediate …

A Multiagent Approach Towards Solving Complex Problems Of Sociotechnical Systems, Hongying Du

Theses and Dissertations

Complex resource allocation problems arise due to complex human societies and scarce resources to be distributed. Scarce resources could be food, water, and energy. Meanwhile, the size of the problem, the intersection of different areas, and possible global consequences all add to the complexity of the problems, which makes it difficult for humans to solve the problems by themselves.

For all these reasons, humans need technical help to tackle complex problems. Since humans participating in the problems usually own part of the information about the problems, and no one may see the whole picture of the problems, it is natural …

Passive Mimo Radar Detection, Daniel E. Hack

Theses and Dissertations

Passive multiple-input multiple-output (MIMO) radar is a sensor network comprised of multiple distributed receivers that detects and localizes targets using the emissions from multiple non-cooperative radio frequency transmitters. This dissertation advances the theory of centralized passive MIMO radar (PMR) detection by proposing two novel generalized likelihood ratio test (GLRT) detectors. The first addresses detection in PMR networks without direct-path signals. The second addresses detection in PMR networks with direct-path signals. The probability distributions of both test statistics are investigated using recent results from random matrix theory. Equivalence is established between PMR networks without direct-path signals and passive source localization (PSL) …

Radio Frequency Based Programmable Logic Controller Anomaly Detection, Samuel J. Stone

Theses and Dissertations

The research goal involved developing improved methods for securing Programmable Logic Controller (PLC) devices against unauthorized entry and mitigating the risk of Supervisory Control and Data Acquisition (SCADA) attack by detecting malicious software and/or trojan hardware. A Correlation Based Anomaly Detection (CBAD) process was developed to enable 1) software anomaly detection discriminating between various operating conditions to detect malfunctioning or malicious software, firmware, etc., and 2) hardware component discrimination discriminating between various hardware components to detect malfunctioning or counterfeit, trojan, etc., components.

Enhancing Electromagnetic Side-Channel Analysis In An Operational Environment, David P. Montminy

Theses and Dissertations

Side-channel attacks exploit the unintentional emissions from cryptographic devices to determine the secret encryption key. This research identifies methods to make attacks demonstrated in an academic environment more operationally relevant. Algebraic cryptanalysis is used to reconcile redundant information extracted from side-channel attacks on the AES key schedule. A novel thresholding technique is used to select key byte guesses for a satisfiability solver resulting in a 97.5% success rate despite failing for 100% of attacks using standard methods. Two techniques are developed to compensate for differences in emissions from training and test devices dramatically improving the effectiveness of cross device template …

Development Of The In Vivo Multicolor Photoacoustic Flow Cytometer, Mustafa Sarimollaoglu

Theses and Dissertations

Flow cytometry is a powerful tool for analysis of cells in artificial flow. This highly accurate technology, using multicolor fluorescent probes and lasers with different wavelengths, provides fast multiparameter quantification of the biological properties of cells. Invasive extraction of cells from an organism, however, leads to changes in cell properties and low sensitivity, and prevents studying cells in their native environment. Challenges to advances in in vivo flow cytometry include fluorescent probe toxicity, strong background, and number of colors, as well as assessment of small vessels. To overcome these limitations, photoacoustic flow cytometry (PAFC) was introduced. PAFC is based on …

Evaluation Of Cyber Sensors For Enhancing Situational Awareness In The Ics Environment, Jeremy R. Otis

Theses and Dissertations

Industrial Control Systems (ICS) monitor and control operations associated with the national critical infrastructure (e.g., electric power grid, oil and gas pipelines and water treatment facilities). These systems rely on technologies and architectures that were designed for system reliability and availability. Security associated with ICS was never an inherent concern, primarily due to the protections afforded by network isolation. However, a trend in ICS operations is to migrate to commercial networks via TCP/IP in order to leverage commodity benefits and cost savings. As a result, system vulnerabilities are now exposed to the online community. Indeed, recent research has demonstrated that …

Dynamic Network Topologies, Heather A. Lingg

Theses and Dissertations

Demand for effective network defense capabilities continues to increase as cyber attacks occur more and more frequently and gain more and more prominence in the media. Current security practices stop after data encryption and network address filtering. Security at the lowest level of network infrastructure allows for greater control of how the network traffic flows around the network. This research details two methods for extending security practices to the physical layer of a network by modifying the network infrastructure. The first method adapts the Advanced Encryption Standard while the second method uses a Steiner tree. After the network connections are …

Classification Of Encrypted Web Traffic Using Machine Learning Algorithms, William C. Barto

Theses and Dissertations

The increasing usage of web services and encrypted network communication makes the network analysis of encrypted web traffic of utmost importance. This research evaluates the feasibility of using ML algorithms to classify web services within encrypted TLS flows. The ML algorithms are compared primarily based on classification accuracy. The runtimes of the classifiers are also considered, as classifiers must be able determine labels quickly in order to be used in near realtime network protection devices. Five ML algorithms are initially considered when analyzing only the first 12 packets: Naive Bayes, NBTree, LibSVM, J4.8, and AdaBoost+J4.8. AdaBoost+J4.8 and J4.8 produce the …

Applied Hypergame Theory For Network Defense, Alan S. Gibson

Theses and Dissertations

Cyber operations are the most important aspect of military conflicts in the 21st century, but unfortunately they are also among the least understood. The continual battle for network dominance between attackers and defenders is considered to be a complex game. Hypergame theory is an extension of game theory that addresses the kind of games where misperception exists, as is often the case in military engagements. Hypergame theory, like game theory, uses a game model to determine strategy selection, but goes beyond game theory by examining subgames that exist within the full game. The inclusion of misperception and misinformation in the …

Evaluating The Effectiveness Of Ip Hopping Via An Address Routing Gateway, Ryan A . Morehart

Theses and Dissertations

This thesis explores the viability of using Internet Protocol (IP) address hopping in front of a network as a defensive measure. This research presents a custom gateway-based IP hopping solution called Address Routing Gateway (ARG) that acts as a transparent IP address hopping gateway. This thesis tests the overall stability of ARG, the accuracy of its classifications, the maximum throughput it can support, and the maximum rate at which it can change IPs and still communicate reliably. This research is accomplished on a physical test network with nodes representing the types of hosts found on a typical, corporate-style network. Direct …

Modeling Cyber Situational Awareness Through Data Fusion, Evan L. Raulerson

Theses and Dissertations

Cyber attacks are compromising networks faster than administrators can respond. Network defenders are unable to become oriented with these attacks, determine the potential impacts, and assess the damages in a timely manner. Since the observations of network sensors are normally disjointed, analysis of the data is overwhelming and time is not spent efficiently. Automation in defending cyber networks requires a level of reasoning for adequate response. Current automated systems are mostly limited to scripted responses. Better defense tools are required. This research develops a framework that aggregates data from heterogeneous network sensors. The collected data is correlated into a single …

A Multi Agent System For Flow-Based Intrusion Detection, David A . Ryan

Theses and Dissertations

The detection and elimination of threats to cyber security is essential for system functionality, protection of valuable information, and preventing costly destruction of assets. This thesis presents a Mobile Multi-Agent Flow-Based IDS called MFIREv3 that provides network anomaly detection of intrusions and automated defense. This version of the MFIRE system includes the development and testing of a Multi-Objective Evolutionary Algorithm (MOEA) for feature selection that provides agents with the optimal set of features for classifying the state of the network. Feature selection provides separable data points for the selected attacks: Worm, Distributed Denial of Service, Man-in-the-Middle, Scan, and Trojan. This …

Characterization And Dynamic Analysis Of Long-Cavity Multi-Section Gain-Levered Quantum-Dot Lasers, John R. Schmidt

Theses and Dissertations

This research investigates the impact of different device architectures on the frequency response of long-cavity multi-section quantum-dot lasers. This work focused on a novel 8.3-mm multi-section quantum-dot device which possessed the flexibility to be configured either as a single- or multi-section device having gain-to-modulation section ratios of 14:2 and 15:1. The long-cavity device design facilitated the testing of increased gain-to-modulation section length ratios previously unexplored in the context of the gain-lever effect. The investigation of the gain-lever effect showed improvements to both the modulation efficiency and modulation bandwidth of the device under test. The modulation efficiency and modulation bandwidth were …