Digital Commons Network^™

Design And Hardware Implementation Of A Novel Scrambling Security Algorithm For Robust Wireless Local Area Networks, Mohit Jagetia

Electronic Theses and Dissertations

The IEEE802.11 standard for wireless networks includes a Wired Equivalent Privacy (WEP) protocol, which is a popular wireless secure communication stream cipher protocol approach to network security used to protect link-layer communications from eavesdropping and other attacks. It allows user to communicate with the user; sharing the public key over a network. It provides authentication and encrypted communications over unsecured channels. However, WEP protocol has an inherent security flaw. It is vulnerable to the various attacks, various experiments has proved that WEP fails to achieve its security goals. This thesis entails designing, evaluating and prototyping a wireless security infrastructure that …

Modifications To The Fuzzy-Artmap Algorithm For Distributed Learning In Large Data Sets, Jose R. Castro

Electronic Theses and Dissertations

The Fuzzy–ARTMAP (FAM) algorithm has been proven to be one of the premier neural network architectures for classification problems. FAM can learn on line and is usually faster than other neural network approaches. Nevertheless the learning time of FAM can slow down considerably when the size of the training set increases into the hundreds of thousands. In this dissertation we apply data partitioning and network partitioning to the FAM algorithm in a sequential and parallel setting to achieve better convergence time and to efficiently train with large databases (hundreds of thousands of patterns). We implement our parallelization on a Beowulf …

Analysis Of Time Synchronization Errors In High Data Rate Ultrawideban, Lakesha Bates

Electronic Theses and Dissertations

Emerging Ultra Wideband (UWB) Orthogonal Frequency Division Multiplexing (OFDM) systems hold the promise of delivering wireless data at high speeds, exceeding hundreds of megabits per second over typical distances of 10 meters or less. The purpose of this Thesis is to estimate the timing accuracies required with such systems in order to achieve Bit Error Rates (BER) of the order of magnitude of 10-12 and thereby avoid overloading the correction of irreducible errors due to misaligned timing errors to a small absolute number of bits in error in real-time relative to a data rate of hundreds of megabits per second. …

Globally-Asynchronous, Locally-Synchronous Wrapper Configurations For, Akarsh Ravi

Electronic Theses and Dissertations

Globally-Asynchronous, Locally-Synchronous (GALS) design techniques employ the finer points of synchronous and asynchronous design methods to eliminate problems arising due to clock distribution, power dissipation, and large area over head. With the recent rise in the demand for System-on-a-Chip (SoC) designs, global clock distribution and power dissipation due to clock distribution are inevitable. In order to reduce/eliminate the effects of the global clock in synchronous designs and large area overhead in asynchronous designs, an alternative approach would be to utilize GALS design techniques. Not only do GALS designs eliminate the issue of using a global clock, they also have smaller …

Circuit Design And Reliability Of A Cmos Receiver, Hong Yang

Electronic Theses and Dissertations

This dissertation explores CMOS RF design and reliability for portable wireless receivers. The objective behind this research is to achieve an increase in integration level, and gain more understanding for RF reliability. The fields covered include device, circuit and system. What is under investigation is a multi-band multi-mode receiver with GSM, DCS-1800 and CDMA compatibility. To my understanding, GSM and CDMA dual-mode mobile phones are progressively investigated in industries, and few commercial products are available. The receiver adopts direct conversion architecture. Some improved circuit design methods are proposed, for example, for low noise amplifier (LNA). Except for band filters, local …

Modeling And Analysis Of Solar Arrays For Grid Connected Systems With Maximum Power Point Tracking, Adje Mensah

HIM 1990-2015

The shrinking of the world’s energy sources has prompted an unprecedented interest in renewable and clean energy sources such as photovoltaic (solar) array. Already popular in space and some industrial power system applications, photovoltaic arrays have yet to become a viable source of energy for most terrestrial applications. For several decades now, engineers have been striving to design reliable and affordable solar array based power systems. One popular approach to achieve reliability is the integration of Maximum Power Point Tracking (MPPT) technology in solar power system design. The purpose of this study was to gain more insight into the nature …

Control Loop Performance Assessment: A Classification Of Methods, Niall O'Connor, Aidan O'Dwyer

Conference papers

This paper presents an overview of a number of controller performance assessment techniques. The techniques discussed are divided into five categories, namely, time domain assessment, frequency domain assessment, minimum variance control (MVC) as a benchmark, statistical analysis, and other more ‘problem specific’ assessment techniques. Recent work, by various authors, in each of the five categories is outlined.

Comparison Between Theoretical And Practical Phase Computation, Pauline Sourdille, Aidan O'Dwyer

Conference papers

Transfer functions which are a composite of delay terms cause problems for computer packages, such as MATLAB, in calculating the frequency response open loop transfer function, as the form of the open loop transfer function is irrational. So, the delay terms have to be approximated. There are several ways to evaluate a delay term. A calculator such as MATHEMATICA uses the exact representation of the delay called the Euler form. A computer package such as MATLAB uses a rational approximation for the delay. Using the MATLAB built-in function pade(n,tau), the open loop transfer function of a system with delay can …

System Identification Using The Delta Operator, Aidan O'Dwyer

Conference papers

The aim of this contribution is to communicate, to a wide audience in signal processing and telecommunications, work that has been carried out, primarily in control engineering, on the use of alternative discrete time operators to the z-domain operator. The advantages of the delta domain operator will be communicated using examples, primarily with the aid of plotted results, to give a creative and easily understood impact. Some original work carried out by the author on identification issues will also be communicated.

Combining Capacitor/Inductor And Idling Asynchronous Motor In Design Of A System For Balance Of A Large Two-Phase Industrial Load Over Three Phases, Eugene Coyle, M Farrell, W. J. Campbell

Conference papers

This paper describes the design and implementation of a new solution to power quality problems associated with large unbalanced nonlinear loads at fine glass furnace production utilities. Such furnaces use two-phase electricity for reasons of enhanced temperature control and in order to maintain consistency of glass viscosity. A significant risk of power failure is introduced due to this requirement. The furnace load is also nonlinear in nature, due to temperature control by electronic power switching. This gives rise to risks associated with high harmonic distortion. A new method in design of filters to alleviate problems associated with this type of …

Data Mining Of Substation Relay Data, Badrul H. Chowdhury, Mythili Chaganti

Electrical and Computer Engineering Faculty Research & Creative Works

Data mining aims to make sense of data by revealing meaningful relationships. This paper discusses data mining techniques applied to data recorded by over current relays at several substations. The purpose is to classify faults, verify relay settings and determine fault induced trip per substations. One of the most demanding tasks at hand is to study the data residing in the relays on a statistical basis. C4.5 approach of data mining (decision tree induction) is discussed in this paper.

Detection Of Basal Cell Carcinoma Using Electrical Impedance And Neural Networks, Rohit Dua, Daryl G. Beetner, William V. Stoecker, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Variations in electrical impedance over frequency might be used to distinguish basal cell carcinoma (BCC) from benign skin lesions, although the patterns that separate the two are nonobvious. Artificial neural networks (ANNs) may be good pattern classifiers for this application. A preliminary study to show the potential of neural networks to distinguish benign from malignant skin lesions using electrical impedance is presented. Electrical impedance was measured in vivo from 1 kHz to 1 MHz at five virtual depths on 18 BCC and 16 benign or premalignant lesions. A feed-forward neural network was trained using back propagation to classify these lesions. …

Dynamic Optimization Of A Multimachine Power System With A Facts Device Using Identification And Control Objectnets, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This work presents a novel technique for dynamic optimization of the electric power grid using brain-like stochastic identifiers and controllers called ObjectNets based on neural network architectures with recurrence. ObjectNets are neural network architectures developed to identify/control a particular object with a specific objective in hand. The IEEE 14 bus multimachine power system with a FACTS device is considered in this paper. The paper focuses on the combined minimization of the terminal voltage deviations and speed deviations at the generator terminals and the bus voltage deviation at the point of contact of the FACTS device to the power network. Simulation …

Neural Network Controller For Manipulation Of Micro-Scale Objects, Vijayakumar Janardhan, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement learning-based neural network (RLNN) controller is presented for the manipulation and handling of micro-scale objects in a microelectromechanical system (MEMS). In MEMS, adhesive, surface tension, friction and van der Waals forces are dominant. Moreover, these forces are typically unknown. The RLNN controller consists of an action NN for compensating the unkoown system dynamics, and a critic NN to tune the weights of the action NN. Using the Lyapunov approach, the uniformly ultimate houndedness (UUB) of the closed-loop tracking error and weight estimates are shown by using a novel weight updates. Simulation results are presented to substantiate the …

Neuroidentification Of System Parameters Of The Upfc In A Multimachine Power System, Radha P. Kalyani, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The crucial factor affecting the modern power systems today is load flow control. The Unified Power Flow Controller is an effective means for controlling the power flow. The UPFC is controlled conventionally using PI controllers. This paper presents the designs of neuroidentifiers that models the system dynamics one-time step ahead making the pathway for the design of adaptive neurocontrollers. Two neuroidentifiers are used for identifying the nonlinear dynamics of a multimachine power system and UPFC, one neuroidentifier for the shunt inverter and another for the series inverter. Simulation results carried out in the PSCAD/EMTDC environments on multimachine power system are …

Iii-Nitride Semiconductors Grown By Plasma Assisted Molecular Beam Epitaxy, Lei He

Theses and Dissertations

III-nitride semiconductors are of great interest owing to their commercial and military applications due to their optoelectronic and mechanical properties. They have been synthesized successfully by many growth methods. Among them, molecular beam epitaxy (MBE) is a promising epitaxial growth method owing to precise control of growth parameters, which significantly affect the film properties, composition, and thickness. However, the understanding of growth mechanism of III-nitride materials grown in this growth regime is far from being complete.In this dissertation, GaN and AIGaN growth mechanism under metal-rich conditions were investigated. The Ga surface desorption behavior during the growth was investigated systematically using …

Adaptive Applications Of Opto-Vlsi Processors In Wdm Networks, Mehrdad Raisi

Theses: Doctorates and Masters

Communication is an inseparable part of human life and its nature continues to evolve and improve. The advent of laser was a herald to the new possibilities in the communication world. In recent years technologies such as Wavelength Division Multiplexing (WDM) and Erbium Doped Fiber Amplifiers (EDFA) have afforded significant boost to the practice of optical communication. At the heart of this brave new world is the need to dynamically/ adaptively steer/route beams of light carrying very large amounts of data. In recent years many techniques have been proposed for this purpose by various researchers. In this study we have …

First Order Sigma-Delta Modulator Of An Oversampling Adc Design In Cmos Using Floating Gate Mosfets, Syam Prasad Sbs Kommana

LSU Master's Theses

We report a new architecture for a sigma-delta oversampling analog-to-digital converter (ADC) in which the first order modulator is realized using the floating gate MOSFETs at the input stage of an integrator and the comparator. The first order modulator is designed using an 8 MHz sampling clock frequency and implemented in a standard 1.5µm n-well CMOS process. The decimator is an off-chip sinc-filter and is programmed using the VERILOG and tested with Altera Flex EPF10K70RC240 FPGA board. The ADC gives an 8-bit resolution with a 65 kHz bandwidth.

Design And Performance Of Electric Shock Absorber, Oly D. Paz

LSU Master's Theses

The electric shock absorber is a device that converts the kinetic energy of an oscillating object into electric energy. This kinetic energy is normally dumped in a form of thermal energy in a conventional, mechanical shock absorber. The electric shock absorber consists of a permanent magnet linear synchronous generator (PMLSG), a spring, and an electric energy accumulator. The major goal of the project is to design and analyze the operation of an electric shock absorber. In order to define the initial requirements that the electric shock absorber has to satisfy, the construction and performance of currently used shock absorbers were …

An Evaluation Of Multiple Branch Predictor And Trace Cache Advanced Fetch Unit Designs For Dynamically Scheduled Superscalar Processors, Slade S. Maurer

LSU Master's Theses

Semiconductor feature size continues to decrease permitting superscalar microprocessors to continue to increase the number of functional units available for execution. As the instruction issue width increases beyond the five instruction average basic block size of integer programs, more than one basic block must be issued per cycle to continue to increase instructions per cycle (IPC) performance. Researchers have created methods of fetching instructions beyond the first taken branch to overcome the bottleneck created by the limitations of conventional single branch predictors. We compare the performance of the multiple branch prediction (MBP) and trace cache (TC) fetch unit optimization methods. …

Watermarking Using Decimal Sequences, Navneet Kumar Mandhani

LSU Master's Theses

This thesis introduces the use of decimal sequences in watermarking to hide information for authentication. The underlying system is based on code division multiple access (CDMA), which is a form of spread spectrum communication. Different algorithms for the use of decimal sequences have been formulated for use in black and white images. The watermark is spread across the carrier image by using the d- sequences of optimal period and retrieval is made by the use of correlation. Matlab version 6.5 was used to implement the algorithms discussed in this thesis. The advantage of using d-sequences over PN sequences is that …

Bluetooth Enabled Ad-Hoc Networks: Performance Evaluation Of A Self-Healing Scatternet Formation Protocol, Rade Trimceski

Dissertations, Master's Theses and Master's Reports - Open

Bluetooth wireless technology is a robust short-range communications system designed for low power (10 meter range) and low cost. It operates in the 2.4 GHz Industrial Scientific Medical (ISM) band and it employs two techniques for minimizing interference: a frequency hopping scheme which nominally splits the 2.400 - 2.485 GHz band in 79 frequency channels and a time division duplex (TDD) scheme which is used to switch to a new frequency channel on 625 μs boundaries. During normal operation a Bluetooth device will be active on a different frequency channel every 625 μs, thus minimizing the chances of continuous interference …

High-Field Quasi-Ballistic Transport In Short Carbon Nanotubes, Ali Javey, Jing Guo, Magnus Paulsson, Qian Wang, Mark S. Lundstrom, Hongjie Dai, David Mann

Department of Electrical and Computer Engineering Faculty Publications

Single walled carbon nanotubes with Pd Ohmic contacts and lengths ranging from several microns down to 10 nm are investigated by electron transport experiments and theory. The mean-free path (MFP) for acoustic phonon scattering is estimated to be lap ~300  nm, and that for optical phonon scattering is lop ~15  nm. Transport through very short (~10  nm) nanotubes is free of significant acoustic and optical phonon scattering and thus ballistic and quasiballistic at the low- and high-bias voltage limits, respectively. High currents of up to 70   μA can flow through a short nanotube. Possible mechanisms for the eventual electrical breakdown …

A Three-Dimensional Quantum Simulation Of Silicon Nanowire Transistors With The Effective Mass Approximation, Jing Wang, Eric Polizzi, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The silicon nanowire transistor (SNWT) is a promising device structure for future integrated circuits, and simulations will be important for understanding its device physics and assessing its ultimate performance limits. In this work, we present a three-dimensional (3D) quantum mechanical simulation approach to treat various SNWTs within the effective-mass approximation. We begin by assuming ballistic transport, which gives the upper performance limit of the devices. The use of a mode space approach (either coupled or uncoupled) produces high computational efficiency that makes our 3D quantum simulator practical for extensive device simulation and design. Scattering in SNWTs is then treated by …

Monolithic Integration Of Dual Optical Elements On High Power Semicond, Laurent Vaissie

Electronic Theses and Dissertations

This dissertation investigates the monolithic integration of dual optical elements on high power semiconductor lasers for emission around 980nm wavelength. In the proposed configuration, light is coupled out of the AlGaAs/GaAs waveguide by a low reflectivity grating coupler towards the substrate where a second monolithic optical element is integrated to improve the device performance or functionality. A fabrication process based on electron beam lithography and plasma etching was developed to control the grating coupler duty cycle and shape. The near-field intensity profile outcoupled by the grating is modeled using a combination of finite-difference time domain (FDTD) analysis of the nonuniform …

Modelling And System Identification For Real Systems, Karolyn Murphy

Theses

The field of system identification and process parameter estimation is an area that has developed rapidly during the past few decades. The approach to the system identification problem can be influenced by many different aspects which include the specific purpose of the identification. In this thesis, system identification for the purpose of controller design is the central theme.

Initially, the work will focus on a number of approaches to real system identification. Particular attention will be made to the classical non-parametric techniques and the more modern parametric estimation techniques using both open- and closed-loop real-time data. A voltage controlled dc …

Development Of A Low Jitter Multiplying Delay Locked Loop, Ian Kennedy

Theses

The clock generator is a critical component in high-speed wireline communication systems. The clocks in these systems mark time at precise regular intervals. Any deviation of the clock edges from these ideal time points is called jitter and it degrades the overall integrity of the communication system. This thesis looks at both phase locked loops (PLLs) and delay locked loops (DLLs) and their ability to provide these precise clocks. Expressions for the thermal noise-induced jitter in both the PLL and DLL are compared. From this, the DLL is shown to possess the potential for better jitter performance. However, to realise …

A Sip Based Multimedia Messaging Service, Donna Griffin

Theses

The Session Initiation Protocol (SIP) is the protocol of choice for establishing multimedia sessions in Universal Mobile Telecommunications System (UMTS) networks as stated by 3GPP. SIP is a protocol that will merge together the cellular and Internet worlds and is also scalable, highly available and extensible. It enables mobile carriers to extend operations, administration, maintenance and provisioning (OAMP) in one application to all applications. In addition, while SIP permits presence. Instant Messaging, File Sharing etc., its ultimate value lies in seamlessly aggregating these applications in more powerful offerings, such as Multimedia Messaging, Push to Talk and Voice over IP.

Multimedia …

Power Flow And Stability Models For Induction Generators Used In Wind Turbines, Kiran K. Nandigam, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Model initialization of the induction generator for the wind power generation is investigated. Incorrect initialization may lead to numerical instability problems, not to mention erroneous result from dynamic simulation. The machine model is studied from the perspective of slip and reactive power calculation and tested for various cases. The dynamic reactive power calculation in well-know software package is discussed and the deviation of dynamic reactive power from the steady state reactive power is highlighted.

High Quality Zno Epitaxial Grown By Plasma Assisted Molecular Beam Epitaxy, Yun Zhang

Theses and Dissertations

Described in this thesis are the growth and characterization of high quality ZnO epitaxy layers.Zinc oxide (ZnO) epitaxy layers were grown on sapphire and epi-GaN substrates respectively, using plasma assisted molecular beam epitaxy (MBE) . Various growth conditions, such as growth temperature, II/VI ratio, and buffer layers, were employed to optimize the quality of the ZnO film. The subsequent characterization of the films was carried out to evaluate the surface, optical and crystalline properties of the film, using AFM, SEM, PL and XRD techniques. It was found out that the high quality of the ZnO film was grown on epi-GaN …