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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Making Radios with GReasy: GNU Radio With FPGAs Made Easy

Marlow, Ryan Lane 29 August 2014 (has links)
Radio technology is rapidly evolving and as processing capabilities and algorithms become more complex, the need for alternative compilation and user interface abstraction increases. Field Programmable Gate Array (FPGA) technology introduces unique reconfigurable hardware architectures that can aid in software defined radio (SDR) design. FPGAs have greater processing capability than traditional general purpose processors (GPP) found in desktop workstations. This work builds on an ongoing project, GReasy, that augments a Linux based open source SDR development platform, GNU Radio, with FPGA processing capabilities. By delegating processing intensive portions of a radio design to the Xilinx Zynq FPGA architecture, the domain of deployable radios by GNU Radio can be broadened. Xilinx Zynq, integrates the FPGA fabric and CPU onto a single chip, which eliminates the need for a controlling host computer; thus, providing a single, portable, low-power, embedded platform. This thesis presents a Zynq capable version of GNU Radio -- an open-source rapid radio deployment tool -- with an enhanced flow that utilizes the processing capability of FPGAs. This work features TFlow -- an FPGA back-end compilation accelerator for instant FPGA assembly. GReasy generates a description of the hardware components that are used by TFlow for the instant FPGA assembly. Once the FPGA is programmed with a design based on the description generated by GReasy, modules and the target hardware can be parameterized to realize an even larger class of applications and further solidify the concept of rapid assembly of software defined radios. / Master of Science
282

Exploits in Concurrency for Boolean Satisfiability

Sohanghpurwala, Ali Asgar Ali Akbar 14 December 2018 (has links)
Boolean Satisfiability (SAT) is a problem that holds great theoretical significance along with effective formulations that benefit many real-world applications. While the general problem is NP-complete, advanced solver algorithms and heuristics allow for fast solutions to many large industrial problems. In addition to SAT, many applications rely on generalizations of Satisfiability such as MaxSAT, and Satisfiability Modulo Theories (SMT). Much of the advancement in SAT solver performance has been in the realm of improved sequential solvers with advanced conflict resolution, learning mechanisms, and sophisticated heuristics. There have been some successful demonstrations of massively parallel and hardware-accelerated solvers for SAT, but these have failed to find their way into mainstream usage. This document first presents previous work in Hardware Acceleration of Satisfiability followed by an analysis of why these attempts failed to gain widespread acceptance. It then demonstrates an alternative, hardware-centric approach, based on distributed Stochastic Local Search (SLS) that is better suited to efficient hardware implementation. Then a parallel SLS/CDCL hybrid approach is proposed that is suitable for distributed search with minimal communication overhead while maintaining completeness. Finally the efficacy and flexibility of distributed local search is considered with an adaptation to Weighted Partial MaxSAT (WPMS) and a focused case study on converted Probabilistic Inference instances. / Ph. D. / The Boolean Satisfiability (SAT) problem is an important decision problem that asks whether there exists a solution that satisfies all given constraints over a set of variables that can assume values of either 0 or 1. May real-world decision problems can be translated into SAT, and there exist efficient sequential solvers that can quickly resolve many such instances. Less progress has been made in efficiently scaling SAT solvers to modern multi-core systems and massively parallel hardware accelerators such as GPUs and Field Programmable Gate Arrays (FPGAs). This thesis explore different approaches to solving SAT based decision and optimization problems with the goal of increasing concurrency.
283

The Effects of Caching on Reconfigurable Adaptive Computing Systems

Hendry, James Hugh 21 January 2004 (has links)
Adaptive computing systems have proven useful for implementing a wide range of algorithms. A limitation of current systems is the relatively small amount of reconfigurable hardware resources. Many algorithms require more hardware resources than are available. One solution to this problem is runtime reconfiguration (RTR). Using RTR techniques, a large algorithm is implemented as a collection of configurations for the reconfigurable hardware. These configurations are loaded onto the reconfigurable hardware as necessary to implement the algorithm. A primary limitation of RTR is that the reconfiguration process is slow. Therefore, methods of decreasing reconfiguration time are desirable. Another method of implementing large algorithms on small hardware is to use multiple configurable computing platforms connected via a communication network. RTR techniques can be used in conjunction with this method to further increase hardware availability. In this case reconfiguration time is increased by the overhead of transmitting data across the communication network. Methods of decreasing network overhead are desirable. This thesis discusses the use of caching techniques to decrease reconfiguration time. An architecture for caching configurations is implemented on a configurable computing system platform. The use of caching to decrease network overhead is discussed and exhibited. An example application is implemented and used to evaluate the effects of caching on reconfiguration time and algorithm performance. / Master of Science
284

A Development Platform to Evaluate UAV Runtime Verification Through Hardware-in-the-loop Simulation

Rafeeq, Akhil Ahmed 17 June 2020 (has links)
The popularity and demand for safe autonomous vehicles are on the rise. Advances in semiconductor technology have led to the integration of a wide range of sensors with high-performance computers, all onboard the autonomous vehicles. The complexity of the software controlling the vehicles has also seen steady growth in recent years. Verifying the control software using traditional verification techniques is difficult and thus increases their safety concerns. Runtime verification is an efficient technique to ensure the autonomous vehicle's actions are limited to a set of acceptable behaviors that are deemed safe. The acceptable behaviors are formally described in linear temporal logic (LTL) specifications. The sensor data is actively monitored to verify its adherence to the LTL specifications using monitors. Corrective action is taken if a violation of a specification is found. An unmanned aerial vehicle (UAV) development platform is proposed for the validation of monitors on configurable hardware. A high-fidelity simulator is used to emulate the UAV and the virtual environment, thereby eliminating the need for a real UAV. The platform interfaces the emulated UAV with monitors implemented on configurable hardware and autopilot software running on a flight controller. The proposed platform allows the implementation of monitors in an isolated and scalable manner. Scenarios violating the LTL specifications can be generated in the simulator to validate the functioning of the monitors. / Master of Science / Safety is one of the most crucial factors considered when designing an autonomous vehicle. Modern vehicles that use a machine learning-based control algorithm can have unpredictable behavior in real-world scenarios that were not anticipated while training the algorithm. Verifying the underlying software code with all possible scenarios is a difficult task. Runtime verification is an efficient solution where a relatively simple set of monitors validate the decisions made by the sophisticated control software against a set of predefined rules. If the monitors detect an erroneous behavior, they initiate a predetermined corrective action. Unmanned aerial vehicles (UAVs), like drones, are a class of autonomous vehicles that use complex software to control their flight. This thesis proposes a platform that allows the development and validation of monitors for UAVs using configurable hardware. The UAV is emulated on a high-fidelity simulator, thereby eliminating the time-consuming process of flying and validating monitors on a real UAV. The platform supports the implementation of multiple monitors that can execute in parallel. Scenarios to violate rules and cause the monitors to trigger corrective actions can easily be generated on the simulator.
285

A Device-Level FPGA Simulator

Hunter, Jesse Everett III 03 August 2004 (has links)
In the realm of FPGAs, many tool vendors offer behaviorally-based simulators aimed at easing the complexity of large FPGA designs. At times, a behaviorally-modeled design does not work in hardware as expected or intended. VTsim, a Virtex-II device simulator, was designed to resolve this and many other design problems by providing a window into the FPGA fabric via a virtual device. VTsim is an event-driven device simulator modeled at the CLB level with multiple clock domain support. Utilizing JBits3 and ADB, VTsim enables simulation and examination of all resources within an FPGA via a virtual device. The only input required by VTsim is a bitstream, which can be generated from any tool suite. The simulator is part of the JHDLBits open-source project, and was designed for rapid response, low memory usage, and ease of interaction. / Master of Science
286

Runtime Intellectual Property Protection on Programmable Platforms

Simpson, Eric 18 July 2007 (has links)
Modern Field-Programmable Gate Arrays (FPGAs) can accommodate complex system-on-chip designs and require extensive intellectual-property (IP) support. However, current IP protection mechanisms in FPGAs are limited, and do not reach beyond whole-design bitstream encryption. This work presents an architecture and protocol for securing IP based designs in programmable platforms. The architecture is reprsented by the Secure Authentication Module (SAM), an enabler for next-generation intellectual-property exchange in complex FPGAs. SAM protects hardware, software, application data, and also provides mutual assurances for the end-user and the intellectual-property developer. Further, this work demonstrates the use of SAM in a secure video messaging device on top of a Virtex-II Pro development system. / Master of Science
287

Framework for a Context-Switching Run-Time Reconfigurable System

Lehn, David Ilan 10 May 2002 (has links)
The reprogrammable nature of configurable computing machines has led to a wealth of research in run-time reconfigurable systems and applications. A limitation often encountered in this research is the slow configuration time with respect to the system clock speed. One technique to deal with these configuration delays has been to develop devices that can hold multiple rapidly interchangeable configurations. This technique is known as context-switching. This thesis discusses the development of a framework to support applications which execute on a run-time reconfigurable system containing context-switching devices. The framework is divided into a number of layers: hardware, middleware, software, and applications. The design, implementation, and details of each layer are presented. / Master of Science
288

A Scalable Approach to Multi-core Prototyping

Newcomb, Jamie David 22 April 2008 (has links)
In recent years, multi-core processors and multi-processor networks have grown in popularity as a solution to the limits on increasing clock speed, rising power consumption, and the nanometer manufacturing processes. Multi-core processors and multi-processor networks are seen as the next step in the advancement of computational capabilities by way of concurrent processing. However, parallel software design is difficult due to the immaturity of scalable architectures and software development environments for multi-core hardware. How should processors effectively and quickly pass information, with as little overhead as possible? What kind of communication architecture is best suited for parallelism? How can large-scale architectures be quickly produced, verified and properly utilized by software? Using commercially available FPGA development boards, Xilinx tools and components, this thesis offers a light-weight solution to these questions for effective, low-overhead, low-latency multi-core communication and fast prototyping of multi-processor networks for scalable processor arrays. / Master of Science
289

Searching Biological Sequence Databases Using Distributed Adaptive Computing

Pappas, Nicholas Peter 06 February 2003 (has links)
Genetic research projects currently can require enormous computing power to processes the vast quantities of data available. Further, DNA sequencing projects are generating data at an exponential rate greater than that of the development microprocessor technology; thus, new, faster methods and techniques of processing this data are needed. One common type of processing involves searching a sequence database for the most similar sequences. Here we present a distributed database search system that utilizes adaptive computing technologies. The search is performed using the Smith-Waterman algorithm, a common sequence comparison algorithm. To reduce the total search time, an initial search is performed using a version of the algorithm, implemented in adaptive computing hardware, which is designed to efficiently perform the initial search. A final search is performed using a complete version of the algorithm. This two-stage search, employing adaptive and distributed hardware, achieves a performance increase of several orders of magnitude over similar processor based systems. / Master of Science
290

Context Switching Strategies in a Run-Time Reconfigurable system

Puttegowda, Kiran 30 April 2002 (has links)
A distinctive feature of run-time reconfigurable systems is the ability to change the configuration of programmable resources during execution. This opens a number of possibilities such as virtualisation of computational resources, simplified routing and in certain applications lower power. Seamless run-time reconfiguration requires rapid configuration. Commodity programmable devices have relatively long configuration time, which makes them poor candidates for run-time reconfigurable systems. Reducing this reconfiguration time to the order of nano seconds will enable rapid run-time reconfiguration. Having multiple configuration planes and switching between them while processing data is one approach towards achieving rapid reconfiguration. An experimental context switching programmable device, called the Context Switching Reconfigurable Computer (CSRC), has been created by BAE Systems, which provided opportunities to explore context-switching strategies for run-time reconfigurable systems. The work presented here studies this approach for run-time reconfiguration, by applying the concepts to develop applications on a context switching reconfigurable system. The work also discusses the advantages and disadvantages of such an approach and ways of leveraging the concept for efficient computing. / Master of Science

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