Physical Sciences and Mathematics Commons^™

The Performance Of Random Prototypes In Hierarchical Models Of Vision, Kendall Lee Stewart

Dissertations and Theses

I investigate properties of HMAX, a computational model of hierarchical processing in the primate visual cortex. High-level cortical neurons have been shown to respond highly to particular natural shapes, such as faces. HMAX models this property with a dictionary of natural shapes, called prototypes, that respond to the presence of those shapes. The resulting set of similarity measurements is an effective descriptor for classifying images. Curiously, prior work has shown that replacing the dictionary of natural shapes with entirely random prototypes has little impact on classification performance. This work explores that phenomenon by studying the performance of random prototypes on …

Evaluation Of Data-Path Topologies For Self-Timed Conditional Statements, Navaneeth Prasannakumar Jamadagni

Dissertations and Theses

This research presents a methodology to evaluate data path topologies that implement a conditional statement for an average-case performance that is better than the worst-case performance. A conditional statement executes one of many alternatives depending on how Boolean conditions evaluate to true or false. Alternatives with simple computations take less time to execute. The self-timed designs can exploit the faster executing alternatives and provide an average-case behavior, where the average depends on the frequency of simple and complex computations, and the difference in the completion times of simple and complex computations. The frequency of simple and complex computations depends on …

Tweakable Ciphers: Constructions And Applications, Robert Seth Terashima

Dissertations and Theses

Tweakable ciphers are a building block used to construct a variety of cryptographic algorithms. Typically, one proves (via a reduction) that a tweakable-cipher-based algorithm is about as secure as the underlying tweakable cipher. Hence improving the security or performance of tweakable ciphers immediately provides corresponding benefits to the wide array of cryptographic algorithms that employ them. We introduce new tweakable ciphers, some of which have better security and others of which have better performance than previous designs. Moreover, we demonstrate that tweakable ciphers can be used directly (as opposed to as a building block) to provide authenticated encryption with associated …

Scalable Equivalence Checking For Behavioral Synthesis, Zhenkun Yang

Dissertations and Theses

Behavioral synthesis is the process of compiling an Electronic System Level (ESL) design to a register-transfer level (RTL) implementation. ESL specifications define the design functionality at a high level of abstraction (e.g., with C/C++ or SystemC), and thus provide a promising approach to address the exacting demands to develop feature-rich, optimized, and complex hardware systems within aggressive time-to-market schedules. Behavioral synthesis entails application of complex and error-prone transformations during the compilation process. Therefore, the adoption of behavioral synthesis highly depends on our ability to ensure that the synthesized RTL conforms to the ESL description. This dissertation provides an end-to-end scalable …

Novel Cryptographic Primitives And Protocols For Censorship Resistance, Kevin Patrick Dyer

Dissertations and Theses

Internet users rely on the availability of websites and digital services to engage in political discussions, report on newsworthy events in real-time, watch videos, etc. However, sometimes those who control networks, such as governments, censor certain websites, block specific applications or throttle encrypted traffic. Understandably, when users are faced with egregious censorship, where certain websites or applications are banned, they seek reliable and efficient means to circumvent such blocks. This tension is evident in countries such as a Iran and China, where the Internet censorship infrastructure is pervasive and continues to increase in scope and effectiveness.

An arms race is …

Post-Silicon Functional Validation With Virtual Prototypes, Kai Cong

Dissertations and Theses

Post-silicon validation has become a critical stage in the system-on-chip (SoC) development cycle, driven by increasing design complexity, higher level of integration and decreasing time-to-market. According to recent reports, post-silicon validation effort comprises more than 50% of the overall development effort of an 65nm SoC. Though post-silicon validation covers many aspects ranging from electronic properties of hardware to performance and power consumption of whole systems, a central task remains validating functional correctness of both hardware and its integration with software. There are several key challenges to achieving accelerated and low-cost post-silicon functional validation. First, there is only limited silicon observability …

Hardware/Software Interface Assurance With Conformance Checking, Li Lei

Dissertations and Theses

Hardware/Software (HW/SW) interfaces are pervasive in modern computer systems. Most of HW/SW interfaces are implemented by devices and their device drivers. Unfortunately, HW/SW interfaces are unreliable and insecure due to their intrinsic complexity and error-prone nature. Moreover, assuring HW/SW interface reliability and security is challenging. First, at the post-silicon validation stage, HW/SW integration validation is largely an ad-hoc and time-consuming process. Second, at the system deployment stage, transient hardware failures and malicious attacks make HW/SW interfaces vulnerable even after intensive testing and validation. In this dissertation, we present a comprehensive solution for HW/SW interface assurance over the system life cycle. …

Novel Methods For Learning And Adaptation In Chemical Reaction Networks, Peter Banda

Dissertations and Theses

State-of-the-art biochemical systems for medical applications and chemical computing are application-specific and cannot be re-programmed or trained once fabricated. The implementation of adaptive biochemical systems that would offer flexibility through programmability and autonomous adaptation faces major challenges because of the large number of required chemical species as well as the timing-sensitive feedback loops required for learning. Currently, biochemistry lacks a systems vision on how the user-level programming interface and abstraction with a subsequent translation to chemistry should look like. By developing adaptation in chemistry, we could replace multiple hard-wired systems with a single programmable template that can be (re)trained to …

Intersections Of Critical Systems Thinking And Community Based Participatory Research In Developing A Web Site For Autistic Adults, Dora Madeline Raymaker

Dissertations and Theses

People with disabilities, including those on the autism spectrum, comprise the world's largest minority and experience significant inequities in Internet use. Existing standards for accessible web sites are necessary but not sufficient without the direct engagement of end users in identifying access needs. Yet little is known about methods for effective engagement, and there are no systematically derived Web accessibility guidelines for autistic end users. Here I explore a hybrid approach to direct engagement using critical systems thinking (CST) and community based participatory research (CBPR) during the co-development of a healthcare-focused web site by the Academic Autism Spectrum Partnership in …

Leveraging Contextual Relationships Between Objects For Localization, Clinton Leif Olson

Dissertations and Theses

Object localization is currently an active area of research in computer vision. The object localization task is to identify all locations of an object class within an image by drawing a bounding box around objects that are instances of that class. Object locations are typically found by computing a classification score over a small window at multiple locations in the image, based on some chosen criteria, and choosing the highest scoring windows as the object bounding-boxes. Localization methods vary widely, but there is a growing trend towards methods that are able to make localization more accurate and efficient through the …