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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.
81

Extended Metamodelica Based Integrated Copiler Generator

Palanisamy, Arunkumar January 2012 (has links)
OMCCp is a new generation (not yet released) of the OpenModelica Compiler-Compiler parser generator which contains an LALR parser generator implemented in the MetaModelica language with parsing tables generated by the tools Flex and GNU Bison. It also contains very good error handling and is integrated with the MetaModelica semantics specification language.   The main benefit with this master thesis project is the development of new version of OMCCp with complete support for an extended Modelica grammar for a complete OMCCp-based Modelica parser. The implemented parser has been tested and the results have been analyzed. This is a new enhanced generation OMCCp with improvements made from the previous version. This version support Modelica as well as the language extensions for MetaModelica, ParModelica, and optimization problem specification. Moreover, the generated parsers are about three times faster than those from the old OMCCp.
82

Photoacid Generators for Catalytic Decomposition of Polycarbonate

Cupta, Mark Glenn 13 January 2006 (has links)
It is the goal of this body of work to research an assortment of different photoacid generators (PAGs) and quantify their ability to perform the decomposition of poly(propylene carbonate) (PPC). Adding PAGs to PPC allows for a decreased polymer decomposition temperature, which can in turn be used as a sacrificial polymer for the fabrication of various microelectromechanical and microfluidic devices. A focus will be placed on relating the properties of the PAG such as acid strength, acid volatility, and PAG activation to processing issues like percentage of total film decomposition, amount and composition of film residue, decomposition rate, decomposition temperature, and environmental dependencies. This research discovered that the use of superacid triflic and nonaflic based PAGs were not adequate for the decomposition of PPC due to the high vapor pressure of the acid. Furthermore, the non-fluorinated sulfonic acid based PAGs do not posses the super-acid level acidity needed to sufficiently decompose PPC. Conversely, a perfluorinated methide and a tetrakis(pentafluoropheyl)borate based PAG both demonstrated the capability for high level PPC decomposition. Building on the knowledge gained through experimentation with these individual PAGs, the creation of a novel Combination PAG was accomplished. The Combination PAG uses acid groups with different physical properties collectively working to achieve what neither could complete individually.
83

Study on Poisson Cluster Stochastic Rainfall Generators

Kim, Dong Kyun 2009 December 1900 (has links)
The purpose of this dissertation is to enhance the applicability and the accuracy of the Poisson cluster stochastic rainfall generators. Firstly, the 6 parameters of the Modified Bartlett-Lewis Rectangular Pulse (MBLRP) stochastic rainfall simulation model were regionalized across the contiguous United States. Each of the parameters of MBLRP model estimated at 3,444 National Climate Data Center (NCDC) rain gages was spatially interpolated based on the Ordinary Kriging technique to produce the parameter surface map for each of the 12 months of the year. Cross-validation was used to assess the validity of the parameter maps. The results indicate that the suggested maps reproduce well the statistics of the observed rainfall for different accumulation intervals, except for the lag-1 autocorrelation coefficient. The estimated parameter values were also used to produce the maps of storm and rain cell characteristics. Secondly, the relative importance of the rainfall statistics in the generation of watershed response characteristics was estimated based on regression analyses using the rainfall time series observed at 1099 NCDC rain gages. The result of the analyses was used to weigh the rainfall statistics differently in the parameter calibration process of MBLRP model. It was observed that synthetic rainfall time series generated weighing the precipitation statistics according to their relative importance outperformed those generated weighing all statistics equally in predicting watershed runoff depths and peak flows. When all statistics were given the same weight, runoff depths and peak flows were underestimated by 20 percent and 14 percent, respectively; while, when the statistics were weighed proportionally to their relative importance, the underestimation was reduced to 4 percent and 3 percent, which confirms the advantage of weighing the statistics differently. In general, the value of the weights depends on the hydrologic process being modeled. Lastly, a stochastic rainfall generation model that can integrate year-to-year variability of rainfall statistics is suggested. The new framework consists of two parts. The first part generates the short-term rainfall statistics based on the correlation between the observed rainfall statistics. The second part generates the rainfall time series using the modified Bartlett-Lewis rectangular pulse model based on the simulated rainfall statistics. The new approach was validated at 104 NCDC gages across the United States in its ability to reproduce rainfall and watershed response characteristics. The result indicates that the new framework outperformed the traditional approach in reproducing the distribution of monthly maximum rainfall depths, monthly runoff volumes and monthly peak flows.
84

Design and Implementaion of a High-Performance Memory Generator

Lee, Wan-Ping 18 August 2004 (has links)
The SRAM memory generator in this thesis is divided into four parts: row decoder, storage cell, column decoder, and sense amplifier & write controller. The row decoder is designed using pass-transistors logic with better area and regularity compared with conventional NAND based decoders. Two different column decoders, tree structure and NOR based predecoder, are provided in current version. Although only SRAM is implemented in this thesis, the memory generator platform is complete with all the necessary models required in the embedded design. In the future, other memories, such as cache, shift register, FIFO, stacks, ROM, register files, and content addressable memory, can be integrated in this memory generator platform.
85

Design and Implementation of a Layout Generator Based on Pass-Transistor Logic

Lin, Su-ya 21 July 2005 (has links)
Conventional logic circuit designs are based on fully complementary CMOS logic circuits. In the past decade, many Pass-Transistor Logic (PTL) circuits have been proposed that are claimed to have better performance in area, speed and power. Most current PTL logic circuits are composed of a limited number of basic PTL cells (say 2 to 5 types of cells only). However, current placement-and-routing (P&R) CAD tools are mainly designed based on CMOS cell library which usually contains many cells with different logic functions. Thus the P&R tool does not fully exploit the features of the synthesized PTL gate-level netlists. In this thesis, we present a P&R tool dedicated to the generation of the final physical layout for the PTL netlists that are generated from a PTL synthesizer. This backend tool considers the efficient placement and routing of the PTL cells in order to reduce the area cost and to reduce the impact of the interconnection wirings on speed and power performances. Besides, in this thesis, the critical paths of the PTL netlists will be identified and the corresponding input patterns to activate these critical paths will be generated for post-layout speed simulation using HSPICE or Nanosim. In summary, the layout generator in this thesis performs the P&R of PTL netlists and also automatically find the critical paths and their corresponding input patterns.
86

IC Design and Implementation of Preamplifier for 16 Mbps Infrared Receiver Module and Reference Clock Generator for DDR Synchronous Devices

Chen, Chi-Wen 15 June 2001 (has links)
Three different topics associated with their respective applications are proposed in this thesis. The first topic is the implementation of a transimpedence preamplifier for 16 Mbps infrared transceiver modules. The design of the preamplifier is aimed at the VFIR (very fast infrared) which is supposed to provide a 16 Mbps data transmission rate. The second topic is focused on the implementation of a robust reference clock generator design for DDR synchronous devices. A pulse generator circuit to generate pulses corresponding to the rise edges and fall edges of a given clock is presented. The third topic is to carry out a cost-effective voice dialer. It focuses on the voice feature extraction and the recognition of Chinese numbers 0 to 9. We present a low-cost method to implement such an algorithm by using 8051-ICE.
87

Application Generator: A Framework and Methodology for IS Construction

Chang, I-chia 07 June 2002 (has links)
¡@¡@There is a general agreement that information system (IS) is one of the effective solutions to help enterprises dealing with the challenge in today¡¦s dynamic environment. In response to the changing business environment, the need for a system with flexibility, high quality, and low cost has increased dramatically. Besides, end users more and more rely on IT (information technologies) or IS for their daily life or work. Therefore, how to attain high software throughput would be highly sought constantly. An idea of reusing previously developed modules, packages, components, software development methodologies, analysis data and test information has been attracting as a keystone to improve software productivity. This approach was called component-based development (CBD) or component-based software engineering (CBSE) and is becoming the main stream of software development. ¡@¡@Various CBD approaches, tools, and techniques were proposed in the literature, however the research on the integration of the above into an environment to enhance the system development is virtually lacking. Therefore, we proposed a framework of application generator, which integrates above approaches and concepts into a collaborative mechanism. Otherwise, we proposed a methodology based on our generator for end users to translate the business models or user requirements into the specification and construct application more efficient. Finally, we apply this methodology to a real-world case and generate the application by the generator in order to verify the feasibility.
88

Design and Implementation of the OFDM Demodulator for DVB-T and the Random Number Generator

Huang, Jian-ming 15 October 2008 (has links)
Digital video broadcasting for Terrestrial (DVB-T) is one of the major standards for the fixed reception of digital television services, and the orthogonal frequency division multiplexing (OFDM) demodulator is a critical module of DVB-T receivers. As the remarkable advace of the VLSI (very large scale integration) circuits, the SOC (system-on-a-chip) of the DVB-T receiver is an inevitabel evolution. Considering the integration of the mixed-signal circuits, the issues ot beat could be the frequency synthesis and the calibration of the mixed-signal circuits. Hence, this thesis proposes an OFDM demodulator and discusses the design issues emerged from the SOC integration. The proposed OFDM demodulator is composed of four blocks: time synchronization, frequency synchronization, 2K/8K mode FFT (fast Fourier transform), and channel estimation. The demodulator utilizes the pilot signals embeded in OFDM symbols to estimate the frequency offset and the channel response. Besides, the demodulator use the cyclic prefix of an OFDM symbol to find the correct starting position of an OFDM symbol, and consequently the payload data of an OFDM symbol can be transmitted to the 2K/8K FFT for further processing. As the demand for a low noise frequency signal, we propose a direct digital frequency synthesizer (DDFS) based on the quadruple angle approximation. According to the proposed trigonometric 2nd-order quadruple angle approximation, the DDFS can produce a high-resolution and low-phase noise digital sinusoid without any ROM (read only memory). The digital calibration is an effective scheme to prevent ADCs (analog-to-digital converter) from the interference of noise. A random number generator (RNG) is an essential component for the calibration circuitry. However, the realization of the RNG is an important but long ignored issue. This thesis proposes a RNG based on a chaotic system wherein the coefficients of the system is dynamically changed to attain an ideal random bit stream with flat power spectrum density.
89

A Study of Simple Thermal Energy Conversion Device

Lai, Wei-ting 11 June 2009 (has links)
The main purpose of this research is to design a thermal energy conversion device, which is aimed to collect unused heat produced by nature. In order to achieve high-efficiency conversion, some novel devices will be studied to convert heat energy into mechanical power. A simple heat exchanger as well as heat engine device is proposed in this study. Dichloromethane is used as an important factor due to its physical properties. Finally, the concept of a tubular linear generator will be adopted to generate electric power. The feature of the proposed simple thermal energy conversion device is that we can use unused heat sources as input, such as solar energy and waste heat from car engines. Besides, the system is capable to work under the condition of low-temperature difference
90

Modeling and Analysis of a Tubular Permanent Magnet Generator with Halbach Array

Lin, Chien-lin 03 September 2009 (has links)
The objective of this thesis is to provide the modeling procedure for a tubular permanent magnet generator with Halbach array. The cylindrical-coordinated magnetic flux distributions generated by the stator winding currents and permanent magnets can be realized by deriving the magnetic vector potential in Bessel form from the Maxwell's equations. Then, the functional expressions of inductance matrix and magnetic flux linkage can be obtained. The detailed mathematic model of the proposed system combined with the actual operational properties can be further established and implemented by using the Matlab/Simulink software. The applicability of such mathematic model is also confirmed with experimental results.

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