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The Design Of An Asynchronous Bcjr/Map Convolutional Channel Decoder., Kristofer Patrick Perta
The Design Of An Asynchronous Bcjr/Map Convolutional Channel Decoder., Kristofer Patrick Perta
Electronic Theses and Dissertations
The digital design alternative to the everyday synchronous circuit design paradigm is the asynchronous model. Asynchronous circuits are also known as handshaking circuits and they may prove to be a feasible design alternative in the modern digital Very Large Scale Integration (VLSI) design environment. Asynchronous circuits and systems offer the possibility of lower system power requirements, reduced noise, elimination of clock skew and many other benefits. Channel coding is a useful means of eliminating erroneous transmission due to the communication channel's physical limits. Convolutional coding has come to the forefront of channel coding discussions due to the usefulness of turbo …
Performance Evaluation Of Hierarchical Ad Hoc Networks., Tai Yu
Performance Evaluation Of Hierarchical Ad Hoc Networks., Tai Yu
Electronic Theses and Dissertations
Ad hoc networking is one of the most challenging areas of wireless communication. Theoretical analysis and experimental results show that QoS (Quality of Service) for each node degrades rapidly while the number of nodes increases in the network. One way to solve performance degradation is to use hierarchical network architectures. In this paper, we investigate performance improvements offered by hierarchical ad hoc networks over flat (non-hierarchical or conventional) ad hoc networks for QoS parameters, namely throughput capacity, delay and power efficiency. We investigated and identified trade-offs among those QoS parameters via computer simulations carried by Network Simulator 2 of University …
A Study On Adaptive Filtering For Noise And Echo Cancellation., Danhua Jiang
A Study On Adaptive Filtering For Noise And Echo Cancellation., Danhua Jiang
Electronic Theses and Dissertations
The objective of this thesis is to investigate the adaptive filtering technique on the application of noise and echo cancellation. As a relatively new area in Digital Signal Processing (DSP), adaptive filters have gained a lot of popularity in the past several decades due to the advantages that they can deal with time-varying digital system and they do not require a priori knowledge of the statistics of the information to be processed. Adaptive filters have been successfully applied in a great many areas such as communications, speech processing, image processing, and noise/echo cancellation. Since Bernard Widrow and his colleagues introduced …
A Framework For Ipsec Functional Architecture., Mehdi. Fahandezh
A Framework For Ipsec Functional Architecture., Mehdi. Fahandezh
Electronic Theses and Dissertations
In today's network, various stand-alone security services and/or proxies are used to provide different security services. These individual security systems implementing one single security function cannot address security needs of evolving networks that require secure protocol such as IPSec. In this paper, we provide a framework for implementing IPSec security functions in a well structured functional architecture. The proposed architecture is modular and allows for composing software applications from products commercially available and developed by different suppliers to implement the entire security requirements of IPSec protocol. In addition the proposed architecture is robust in the sense that it supports open …
Iterative Multiuser Detection With Integrated Channel Estimation For Turbo Coded Ds-Cdma., Shuvojit Chowdhury
Iterative Multiuser Detection With Integrated Channel Estimation For Turbo Coded Ds-Cdma., Shuvojit Chowdhury
Electronic Theses and Dissertations
In present days the demand of high bandwidth and data rate in wireless communications is increasing rapidly to accommodate multimedia applications, including services such as wireless video and high-speed Internet access. In this thesis, we propose a receiver algorithm for mobile communications systems which apply CDMA (Code division multiple access) as multiple access technique. Multiuser Detection and turbo coding are the two most powerful techniques for enhancing the performance of future wireless services. The standardization of direct sequence CDMA (DS-CDMA) systems in the third generation of mobile communication system has raised the interest in exploiting the capabilities and capacity of …
Efficient Quadratic Placement For Fpgas., Yonghong Xu
Efficient Quadratic Placement For Fpgas., Yonghong Xu
Electronic Theses and Dissertations
Field Programmable Gate Arrays (FPGAs) are widely used in industry because they can implement any digital circuit on site simply by specifying programmable logic and their interconnections. However, this rapid prototyping advantage may be adversely affected because of the long compile time, which is dominated by placement and routing. This issue is of great importance, especially as the logic capacities of FPGAs continue to grow. This thesis focuses on the placement phase of FPGA Computer Aided Design (CAD) flow and presents a fast, high quality, wirelength-driven placement algorithm for FPGAs that is based on the quadratic placement approach. In this …
Investigation Into Arithmetic Sub-Cells For Digital Multiplication., G. Michael Howard
Investigation Into Arithmetic Sub-Cells For Digital Multiplication., G. Michael Howard
Electronic Theses and Dissertations
A study of several low-power and high-speed (3,2) counter designs is initially presented, then based on these findings, a new 4:2 compressor design is introduced and proven against other existing and newly devised 4:2 compressors using various logic styles. The results obtained with regards to speed, power and size were used to categorize the circuits in terms of individual and cumulative performance characteristics. A complete 16-bit multiplier design which uses a highly efficient layout scheme along with the top performing 4:2 compressor form the above study is presented. A second multiplier using industry standard (3,2) counters in a 4:2 compressor …
Mobile-Ip Ad-Hoc Network Mpls-Based With Qos Support., Sasan Adibi
Mobile-Ip Ad-Hoc Network Mpls-Based With Qos Support., Sasan Adibi
Electronic Theses and Dissertations
The support for Quality of Service (QoS) is the main focus of this thesis. Major issues and challenges for Mobile-IP Ad-Hoc Networks (MANETs) to support QoS in a multi-layer manner are considered discussed and investigated through simulation setups. Different parameters contributing to the subjective measures of QoS have been considered and consequently, appropriate testbeds were formed to measure these parameters and compare them to other schemes to check for superiority. These parameters are: Maximum Round-Trip Delay (MRTD), Minimum Bandwidth Guaranteed (MBG), Bit Error Rate (BER), Packet Loss Ratio (PER), End-To-End Delay (ETED), and Packet Drop Ratio (PDR) to name a …
Novel Arithmetic Implementations Using Cellular Neural Network Arrays., Youssef Ibrahim
Novel Arithmetic Implementations Using Cellular Neural Network Arrays., Youssef Ibrahim
Electronic Theses and Dissertations
The primary goal of this research is to explore the use of arrays of analog self-synchronized cells---the cellular neural network (CNN) paradigm---in the implementation of novel digital arithmetic architectures. In exploring this paradigm we also discover that the implementation of these CNN arrays produces very low system noise; that is, noise generated by the rapid switching of current through power supply die connections---so called di/dt noise. With the migration to sub 100 nanometer process technology, signal integrity is becoming a critical issue when integrating analog and digital components onto the same chip, and so the CNN architectural paradigm offers a …
A High Level Synthesis Of A Fibre Channel Core For A System-On-Chip Implementation., Till. Kuendiger
A High Level Synthesis Of A Fibre Channel Core For A System-On-Chip Implementation., Till. Kuendiger
Electronic Theses and Dissertations
A high performance standardized System-on-Chip (SoC ) communication system has been developed as an embedded core. A high level synthesis of a Fibre Channel core has been realized that takes advantage of the performance advantages and specifications associated with the Fibre Channel protocol. A soft IP core of a Fibre Channel port is presented in the form of a register transfer level (RTL) descriptor language which can be implemented in arbitrary target technologies. A full-speed (1.0625 GHz link clock) sign-off quality tape-out of the design in TSMC's 0.18 mum technology has been carried out using a design flow centered on …
An Intelligent Control System For Die Casting Processes., Tiebao Yang
An Intelligent Control System For Die Casting Processes., Tiebao Yang
Electronic Theses and Dissertations
The objective of this thesis is to design an intelligent control system for die casting processes involving cooling of a die with multiple channels. The work consists of two parks. First, a correlation between die insert temperature and cooling water outlet temperature is established, which can be used to deduce local die surface temperatures without destructively inserting thermal sensors into a die from its back. Second, a new on-line thermal management scheme is proposed based on an intelligent real-time monitoring and control system (IRMCS) developed for a die insert containing multiple cooling channels. In this scheme, extra cooling water lines …
Electric Surface Properties Of Delrin Used For High Voltage Insulation., Hadi Tajalli
Electric Surface Properties Of Delrin Used For High Voltage Insulation., Hadi Tajalli
Electronic Theses and Dissertations
In this study surface properties of Delrin have been investigated. Delrin is a homopolymer of acetal resin. To study the degradation and the effect of the environment on the surface of this material, samples of Delrin were immersed in saline water with salinities of 0.005-100 mS/cm at 0, 23, 60 and 98 °C. Specimens were also placed in air at these four temperatures. The contact angle of a 4 mu1 sessile droplet of distilled water on the surface of Delrin as a measure of the surface wetability or the hydrophobicity has been measured in this study. Increasing the parameters of …
Speech Enhancement Using Auditory Filterbank., Yang Gui
Speech Enhancement Using Auditory Filterbank., Yang Gui
Electronic Theses and Dissertations
This thesis presents a novel subband noise reduction technique for speech enhancement, termed as Adaptive Subband Wiener Filtering (ASWF), based on a critical-band gammatone filterbank. The ASWF is derived from a generalized Subband Wiener Filtering (SWF) equation and reduces noises according to the estimated signal-to-noise ratio (SNR) in each auditory channel and in each time frame. The design of a subband noise estimator, suitable for some real-life noise environments, is also presented. This denoising technique would be beneficial for some auditory-based speech and audio applications, e.g. to enhance the robustness of sound processing in cochlear implants. Comprehensive objective and subjective …
Efficient Implementation Of Elliptic Curve Cryptography., Bijan Ansari
Efficient Implementation Of Elliptic Curve Cryptography., Bijan Ansari
Electronic Theses and Dissertations
Elliptic Curve Cryptosystems (ECC) were introduced in 1985 by Neal Koblitz and Victor Miller. Small key size made elliptic curve attractive for public key cryptosystem implementation. This thesis introduces solutions of efficient implementation of ECC in algorithmic level and in computation level. In algorithmic level, a fast parallel elliptic curve scalar multiplication algorithm based on a dual-processor hardware system is developed. The method has an average computation time of n3 Elliptic Curve Point Addition on an n-bit scalar. The improvement is n Elliptic Curve Point Doubling compared to conventional methods. When a proper coordinate system and binary representation for the …
Models For Analysis Of Discharge In Gases., Nimal Weeratunga Weeratunga Arachchige
Models For Analysis Of Discharge In Gases., Nimal Weeratunga Weeratunga Arachchige
Electronic Theses and Dissertations
The objective of this thesis is to demonstrate a new concept of modeling gaseous discharges. It has been noticed that theoretical calculated gaseous discharge parameters deviate considerably from the experimentally obtained values. All previous studies on the electron energy distribution within the gaseous discharge have been considered as one single distribution with one mean energy level. During this study two electron energy distributions, representing majority and minority of electrons in the gaseous discharge, with two mean energy values has been considered. The study reveals that the deviation of theoretical calculated discharge parameters and experimentally obtained values were greatly reduced with …