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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.
171

A Unified Model of Pattern-Matching Circuits for Field-Programmable Gate Arrays

Clark, Christopher R. 28 August 2006 (has links)
The objective of this dissertation is to develop a methodology for describing the functionality, analyzing the complexity, and evaluating the performance of a large class of pattern-matching circuit design approaches for field-programmable gate arrays (FPGAs). The developed methodology consists of three elements. The first is a functional model and associated nomenclature that unifies a significant portion of published circuit design approaches while also illuminating many novel approaches. The second is a set of analytical expressions that model the area and time complexity of each circuit design approach based on attributes of a given pattern set. Third, software tools are developed that facilitate architectural design space exploration and circuit implementation. This methodology is used to conduct an extensive evaluation and comparison of design approaches under a wide range of conditions using pattern sets from multiple application domains as well as synthetic pattern sets. The results indicate strong dependences between pattern set properties and circuit performance and provide new insights on the fundamental nature of various design approaches. A number of techniques have been proposed for designing pattern-matching hardware circuits with reconfigurable FPGA chips. The use of FPGAs enables high performance because the circuits can be customized for a particular application and pattern set. A relatively unstudied consequence of tailoring circuits for specific patterns is that circuit area and performance are affected by various properties of the patterns used. Most previous work in this field only considers a single design approach and a small number of pattern sets. Therefore, it is not clear how each design is affected by pattern set properties. For a given set of patterns, it is difficult to determine which approach would be the most efficient or provide the highest performance. Previous attempts to compare approaches using results from different publications are conflicting and inconclusive due to variations in the FPGA devices, patterns, and circuit optimizations used. There has been no attempt to evaluate a wide range of designs under a common set of conditions. The methodology presented in this dissertation provides a framework for studying multiple aspects of FPGA pattern-matching circuits in a controlled and consistent manner.
172

A Study on Three-Dimensional Cellular Automata ¡V Oil Spill Transport as an Example

Sung, Hung-chun 26 July 2005 (has links)
Extensive oil drilling and transportation activities increase the possibility of oil spills and the consequent threat of oil pollution to the regional environment. Oil spills are hazards for marine and freshwater environments. Oil spill/slick detection, monitoring and management has received considerable attention over the past few years. It is a highly non-linear problem to predict oil slick movement and spreading, and it is a subject of complicated science. Oil spill behavior become more complicated while involving the effects of winds, surface currents, oil evaporation, shoreline deposition, land boundary, vertical dispersion and underwater current. Cellular Automata is a solution for problems of complicated science. A three-dimensional model for the prediction of oil slick movement and spreading using Cellular Automata is presented in this paper. The effects of winds, surface currents, oil evaporation, shoreline deposition, land boundary and vertical dispersion have been taken into account while processing the surface cells. At the same time, the effects of underwater currents and land boundary have been taken into account while processing the underwater cells. The algorithm has been used to simulate hypothetical oil slick movement and spreading in hypothetical geographic regions. The results of the simulation are qualitative agreed with real oil slick movement and spreading.
173

Integrated assessment of coastal zone management¡Ðthe case study of the coastal zone near Chang Hua Coastal Industrial Park

Lee, Meng-tsung 19 July 2007 (has links)
The overuse of the coastal resources and overdevelopment on coastal areas led to the result of serious destruction of nature landscape and coastal resources due to the abundance of coastal resources. To avoid the improper development on the coastal areas, it is necessary to have an integrated consideration over the engineering, ecosystem, economics, environmental protection and sustainable development based on the character of coastal land. Therefore, the main conception of this study is to apply the concept of Integrated Coastal Zone Management (ICZM) to take all aspects which might affect the coastal management into integrated consideration, and to accomplish the concept of ICZM by Integrated Assessment (IA). Furthermore, the study constructed a indicator structure of assess coastal management by Driving forces¡VPressures¡VStates¡VImpacts¡VResponses (DPSIR), which takes the production, ecosystem and living environment as three core assessment indicators. Finally, the conceptual model of integrated coastal management is constructed with the help of System Dynamic (SD) and Cellular Automata (CA). This study simulates the influence of the existence of Chang Hua Coastal Industrial Park on the nearby areas such as Hsienhsi county, Hemei town and Lukang town from 1991 to 2021. The main consideration is on the time-series variation of three core indicators and some critical variables as well as the mid-term to long-term tendency on the land use. Three kinds of actions are set for the scenario analysis, including single strategy, multi strategies and progressively varying strategies. According to the simulation results, the action of multi strategies results in the best performance on three core indicators, and the action of single strategy is the worst on the contrary. On seeing the blooming problems over simulation period, the progressively varying strategies are applied in specific time points, and result in better or worse performances depending on different restrictions and resources. The conceptual model constructed in this research is adaptive to simulate the varying tendency on the nearby areas due to the existence of coastal industrial park, and is an efficient and effective assessing measure for the decision persons or the paper worker to understand the influences on different scenarios or strategies applied. Thus better formulations or suggestions over destination areas will be made to help fulfill the concept of ICZM.
174

Analytical Solution of the Continuous Cellular Automaton for Anisotropic Etching

Gosálvez, Miguel A., Xing, Yan, Sato, Kazuo, 佐藤, 一雄 04 1900 (has links)
No description available.
175

Verifying transformations between timed automata specifications and ECA rules

Ericsson, Ann-Marie January 2003 (has links)
<p>Event-triggered real-time systems are desirable to use in environments where the arrival of events are hard to predict. The semantics of an event-triggered system is well mapped to the behaviour of an active database management system (ADBMS), specified using event-condition-action (ECA) rules. The benefits of using an active database, such as persistent data storage, concurrency control, timely response to event occurrences etc. highlights the need for a development method for event-triggered real-time systems using active databases.</p><p>However, there are problems left to be solved before an ADBMS can be used with confidence in real-time environments. The behaviour of a real-time system must be predictable, which implies a thorough analysed specification with e.g. specified worst case execution times. The predictability requirement is an obstacle for specifying real-time systems as ECA rules, since the rules may affect each other in many intricate ways which makes them hard to analyse. The interaction between the rules implies that it is not enough to verify the correctness of single rules; an analysis must consider the behaviour of the entire rule set.</p><p>In this dissertation, an approach for developing active applications is presented. A method is examined which starts with an analysed high-level timed automaton specification and transforms the specified behaviour into an implicitly analysed rule set. For this method to be useful, the transformation from timed automata to rules must preserve the exact behaviour of the high level specification. Hence, the aim of this dissertation is to verify transformations between timed automaton specifications and ECA rules.</p><p>The contribution of this project is a structured set of general transformations between timed automata specifications and ECA rules. The transformations include both transformations of small timed automata constructs for deterministic environments and formally verified timed automata patterns specifying the behaviour of composite events in recent and chronicle context.</p>
176

An Application Developed for Simulation of Electrical Excitation and Conduction in a 3D Human Heart

Yu, Di 01 January 2013 (has links)
This thesis first reviews the history of General Purpose computing Graphic Processing Unit (GPGPU) and then introduces the fundamental problems that are suitable for GPGPU algorithm. The architecture of GPGPU is compared against modern CPU architecture, and the fundamental difference is outlined. The programming challenges faced by GPGPU and the techniques utilized to overcome these issues are evaluated and discussed. The second part of the thesis presents an application developed with GPGPU technology to simulate the electrical excitation and conduction in a 3D human heart model based on cellular automata model. The algorithm and implementation are discussed in detail and the performance of GPU is compared against CPU.
177

Semi-formal verifcation of analog mixed signal systems using multi-domain modeling languages

Ramirez, Ricardo, active 2013 18 December 2013 (has links)
The verification of analog designs has been a challenging task for a few years now. Several approaches have been taken to tackle the main problem related to the complexity that such task presents to design and verification teams. The methodology presented in this document is based on the experiences and research work carried out by the Concordia University's Hardware Verification and the U. of Texas' IC systems design groups. The representation of complex systems where different interactions either mechanical or electrical take place requires an intricate set of mathematical descriptions which greatly vary according to the system under test. As a simple and very relevant example one can look at the integration of RF-MEMS as active elements in System-On-Chip architectures. In order to tackle such heterogeneous interaction for a consistent model, the use of stochastic hybrid models is described and implemented for very simple examples using high level modeling tools for a succinct and precise description. / text
178

Adder and multiplier design and analysis in quantum-dot cellular automata

Cho, Heumpil 28 August 2008 (has links)
Not available / text
179

Design of parallel multipliers and dividers in quantum-dot cellular automata

Kim, Seong-Wan 21 June 2011 (has links)
Conventional CMOS (the current dominant technology for VLSI) implemented with ever smaller transistors is expected to encounter serious problems in the near future with the need for difficult fabrication technologies. The most important problem is heat generation. The desire for device density, power dissipation and performance improvement necessitates new technologies that will provide innovative solutions to integration and computations. Nanotechnology, especially Quantum-dot Cellular Automata (QCA) provides new possibilities for computing owing to its unique properties. Numerous nanoelectronic devices are being investigated and many experimental devices have been developed. Thus, high level circuit design is needed to keep pace with changing physical studies. The circuit design aspects of QCA have not been studied much because of its novelty. Arithmetic units, especially multipliers and dividers play an important role in the design of digital processors and application specific systems. Therefore, designs for parallel multipliers and dividers are presented using this technology. Optimal design of parallel multipliers for Quantum-Dot Cellular Automata is explored in this dissertation. As a main basic element to build multipliers, adders are implemented and compared their performances with previous adders. And two different layout schemes that single layer and multi-layer wire crossings are compared and analyzed. This dissertation proposes three kinds of multipliers. Wallace and Dadda parallel multipliers, quasi-modular multipliers, and array multipliers are designed and simulated with several different operand sizes. Also array multipliers that are well suited in QCA are constructed and formed by a regular lattice of identical functional units so that the structure is conformable to QCA technology without extra wire delay. All these designs are constructed using coplanar layouts and compared with other QCA multipliers. The delay, area and complexity are compared for several different operand sizes. This research also studies divider designs for quantum-dot cellular automata. A digit recurrence restoring binary divider is a conventional design that serves as a baseline. By using controlled full subtractor cell units, a relatively simple and efficient implementation is realized. The Goldschmidt divider using the new architecture (data tag method) to control the various elements of the divider is compared for the performance. / text
180

Modified non-restoring division algorithm with improved delay profile

Jun, Kihwan 11 July 2011 (has links)
This thesis focuses on reducing the delay of non-restoring division. Although the digit recurrence division is lower in complexity and occupies a smaller area than division by convergence, it has a drawback: slow division speed. To mitigate this problem, two modification ideas are proposed here for the non-restoring division, the fastest division algorithm of the digit recurrence division methods. For the first proposed approach, the delay of the multiplexer for selecting the quotient digit and determining the way to calculate the partial remainder can be reduced through inverting the order of its flowchart. Second, one adder and one inverter can be removed by using a new quotient digit converter. To prove these ideas are valid, the simulation results comparing the modified non-restoring division and the standard non-restoring division are provided. / text

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