• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • Tagged with
  • 21
  • 21
  • 12
  • 12
  • 12
  • 12
  • 7
  • 7
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 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.
11

It is I: An Authentication System for a Reconfigurable Radio

Abraham, Arya 13 August 2002 (has links)
The security of a radio system hinges on its ability to effectively authenticate a user. This work proposes a two-factor authentication scheme using a token and a biometric. The users' access rights are determined during authentication and the users are served only those channels of data that they are privileged to receive. The strengths and the weaknesses of the implementation in reconfigurable hardware are identified. The capabilities of the scheme are put into perspective by comparing it to a high-end authentication system and by evaluating the use of standardized APIs and low-end authentication devices. Modifications to the system are suggested to improve the level of security the scheme provides. Finally, a baseline study is carried out to measure the data processing performance of a radio developed in reconfigurable hardware, which uses the proposed authentication scheme. / Master of Science
12

A Design Assembly Technique for FPGA Back-End Acceleration

Frangieh, Tannous 19 October 2012 (has links)
Long wait times constitute a bottleneck limiting the number of compilation runs performed in a day, thus risking to restrict Field-Programmable Gate Array (FPGA) adaptation in modern computing platforms. This work presents an FPGA development paradigm that exploits logic variance and hierarchy as a means to increase FPGA productivity. The practical tasks of logic partitioning, placement and routing are examined and a resulting assembly framework, Quick Flow (qFlow), is implemented. Experiments show up to 10x speed-ups using the proposed paradigm compared to vendor tool flows. / Ph. D.
13

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
14

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
15

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
16

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
17

VLSI Implementation of a Run-time Reconfigurable Custom Computing Integrated Circuit

Musgrove, Mark D. 07 November 1996 (has links)
The growth of high performance computing to date can largely be attributed to continuing breakthroughs in materials and manufacturing.In order to increase computing capacity beyond these physical bounds, new computing paradigms must be developed that make more efficient use of existing manufacturing technologies. Custom Computing Machines (CCMs) are an emerging class of computers that offer promising possibilities for future high-performance computational needs. With the increasing popularity of the run-time reconfigurable (RTR) concept in the CCM community, questions have arisen as to what computational device should be at the heart of an RTR platform. Currently the preferred device, and really the only practical device, has been the RAM-based Field-Programmable Gate Array (FPGA). Unfortunately, for applications that require high performance, FPGAs are limited by their narrow data path and small computational density. The Colt integrated circuit has been designed from the start to be the computational processing element in an RTR platform. Colt is an RTR data-flow processor array with a course-grain architecture (16-bit data path). This thesis covers the VLSI implementation and verification of the Colt integrated circuit, including the approach and methods necessary to make a functionally working integrated circuit. / Master of Science
18

Design and Implementation of an FPGA-based Soft-Radio Receiver Utilizing Adaptive Tracking

Davies, John Clay IV 14 September 2000 (has links)
The wireless market of the future will demand inexpensive hardware, expandability, interoperability, and the implementation of advanced signal processing functions--i.e. a software radio. Configurable computing machines are often ideal software radio platforms. In particular, the Stallion reconfigurable processor's efficient hardware reuse and scalability fulfill these radios' demands. The advantages of Stallion-based design inspired an FPGA-based software radio - the proto-Stallion receiver. This thesis introduces the proto-Stallion architecture and details its implementation on the SLAAC-1V FPGA platform. Although this thesis presents a specific radio implementation, this architecture is flexible; it can support a variety of applications within its fixed framework. This implemented single-user DS-CDMA receiver utilizes an LMS adaptive filter that can combat MAI and constructively combine multipath; most notably, this receiver employs an adaptive tracking algorithm that harnesses the LMS algorithm to maintain symbol synchronization. The proto-Stallion receiver demonstrates the dependence of adaptive tracking on channel noise; the algorithm requires significant noise levels to maintain synchronization. / Master of Science
19

An FPGA-Based Multiuser Receiver Employing Parallel Interference Cancellation

Swanchara, Steven F. 17 September 1998 (has links)
Research efforts have shown that capacity in a DS/CDMA cellular system can be increased through the use of digital signal processing techniques that exploit the nature of the multiple access interference (MAI). By jointly demodulating the users in the system, this interference can be characterized and reduced thus decreasing the overall probability of error in the system. Numerous multiuser structures exist, each with varying degrees of complexity and performance. However, the size and complexity of these structures is large relative to a conventional receiver. This effort demonstrates a practical approach to implementing parallel interference cancellation applied to DBPSK DS/CDMA on an FPGA-based configurable computing platform. The system presented acquires, tracks, cancels, and demodulates four users independently and performs various levels of interference cancellation. The performance gain of the receiver in a four-user environment under various levels of noise and cancellation are presented. / Master of Science
20

Spectrum-Aware Orthogonal Frequency Division Multiplexing

Recio, Adolfo Leon 30 December 2010 (has links)
Reconfigurable computing architectures are well suited for the dynamic data flow processing requirements of software-defined radio. The software radio concept has quickly evolved to include spectrum sensing, awareness, and cognitive algorithms for machine learning resulting in the cognitive radio model. This work explores the application of reconfigurable hardware to the physical layer of cognitive radios using non-contiguous multi-carrier radio techniques. The practical tasks of spectrum sensing, frame detection, synchronization, channel estimation, and mutual interference mitigation are challenges in the communications and the computing fields that are addressed to optimally utilize the capacity of opportunistically allocated spectrum bands. FPGA implementations of parameterizable OFDM and filter bank multi-carrier (FBMC) radio prototypes with spectrum awareness and non-contiguous sub-carrier allocation were completed and tested over-the-air. Sub-carrier sparseness assumptions were validated under practical implementation and performance considerations. A novel algorithm for frame detection and synchronization with mutual interference rejection applicable to the FBMC case was proposed and tested. / Ph. D.

Page generated in 0.055 seconds