Digital Commons Network^™

Turbo Codes: The Issue Of Average Union Upper Bound Under Imperfect Channel State Information In Rayleigh Fading Channels, Erhan A. İnce, Syed Amjad Ali

Turkish Journal of Electrical Engineering and Computer Sciences

The potential of turbo codes to demonstrate excellent performance in the region of low signal to noise ratio is now a familiar fact. The idea of turbo codes was first introduced by Berrou and was based on the clever utilization of the existing decoding mechanism of BCJR with a change in the encoder by introducing feedback and an interleaver in the overall scheme. Since then, these powerful forward error correcting codes have attained a significant attention and have either replaced or have become a sturdy candidate for many applications in this era of modern communication systems. So far, a lot …

Performance Analysis Of A Fuzzy Logic Based Rotor Resistance Estimator Of An Indirect Vector Controlled Induction Motor Drive, Y. Miloud, Azeddine Draou

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a simple method for estimating rotor resistance in an indirect vector-controlled induction motor drive. This is important in vector control, if high-performance torque control is needed. For this purpose, a rotor resistance estimator using fuzzy logic technique is used and analysis, design, and digital simulations are carried out to demonstrate the effectiveness of the proposed estimator.

A Content-Based Fuzzy Image Database Based On The Fuzzy Artmap Architecture, M. Uysal, Fatoş Tünay Yarman Vural

Turkish Journal of Electrical Engineering and Computer Sciences

A major design issue in content-based image retrieval system is the selection of the feature set. This study attacks the problem of finding a discriminative feature for each class, which is optimal in some sense. Fuzzy ARTMAP architecture is used to find this discriminative feature set. For this purpose, initially, a large variety of features are extracted from the regions of the pre-segmented images. Then, the feature set of each object class is learned using the Fuzzy Art Map Architecture, by identifying the weights of each feature for each object class. In the querying phase, trained set of feature weights …

Design Of A Dynamic Focusing Microscope Objective For Oct Imaging, Supraja Murali

Electronic Theses and Dissertations

Optical Coherence Tomography (OCT) is a novel optical imaging technique that has assumed significant importance in bio-medical imaging in the last two decades because it is non-invasive and provides accurate, high resolution images of three dimensional cross-sections of body tissue, exceeding the capabilities of the current predominant imaging technique –ultrasound. In this thesis, high resolution OCT is investigated for in vivo detection of abnormal skin pathology for the early diagnosis of cancer. The technology presented is based on a dynamic focusing microscopic imaging probe conceived for skin imaging and the detection of abnormalities in the epithelium. A novel method for …

Refractive Indices Of Liquid Crystals And Their Applications In Display And Photonic Devices, Jun Li

Electronic Theses and Dissertations

Liquid crystals (LCs) are important materials for flat panel display and photonic devices. Most LC devices use electrical field-, magnetic field-, or temperature-induced refractive index change to modulate the incident light. Molecular constituents, wavelength, and temperature are the three primary factors determining the liquid crystal refractive indices: ne and no for the extraordinary and ordinary rays, respectively. In this dissertation, we derive several physical models for describing the wavelength and temperature effects on liquid crystal refractive indices, average refractive index, and birefringence. Based on these models, we develop some high temperature gradient refractive index LC mixtures for photonic applications, such …

Giant Magneto-Impedance Effect In Thin Film Layered Structures, Amruta Borge

Electronic Theses and Dissertations

Recently, the giant magneto impedance (GMI) effect has been studied extensively because of its potential applications in sensor elements. The focus of this thesis work is to explore different compositions and processing conditions for CoSiB and NiFe thin films to obtain the soft magnetic properties and to evaluate their potential use in GMI sensor applications. Prior to this study, an MH Looper was constructed, which was extremely important and provided the basic magnetic characterization of the many ferromagnetic thin films deposited during this work. The CoSiB films were co-sputter deposited in an ultra high vacuum chamber. Films with different relative …

Effect Of Annealing On Copper Thin Films:The Classical Size Effect And Agglomeration, Parag Gadkari

Electronic Theses and Dissertations

With continued shrinking of CMOS technology to reduce the gate delay times, an increase in the resistivity of the metal corresponding to the wire dimension is a concern. This phenomenon of increase in resistivity with decreasing dimension of the thin metallic film or interconnect is known as the "classical size effect". Various theories have been postulated to explain the phenomenon of classical size effect; these theories can be broadly classified as resistivity due to scattering arising from surface and grain boundaries. The total resistivity of metals depends on the electron scattering due to impurities, phonons, surfaces, grain boundaries, and other …

Analysis And Design Of Miniaturized Rf Saw Duplexer Package, Hao Dong

Electronic Theses and Dissertations

This dissertation provides a comprehensive methodology for accurate analysis and design of miniaturized radio frequency (RF) surface acoustic wave (SAW) duplexer package. Full-wave analysis based on the three dimensional (3-D) finite element method (FEM) is successfully applied to model the package. The die model is obtained by combining the acoustics and die busbars parasitics models. The acoustics model is obtained using the coupling-of-models (COM) technique. The die busbars, bonding wires and printed circuit board (PCB) are modeled using full-wave analysis. After that, the models of package, die, and bonding wires are assembled together to get the total response. To take …

Preparation And Characterization Of Cigss Solar Cells And Pv Module Data Analysis, Jyoti Shirolikar

Electronic Theses and Dissertations

In this thesis, multiple activities have been carried out in order to improve the process of CIGSS solar cell fabrication on a 4" x 4" substrate. The process of CIGSS solar cell fabrication at FSEC's PV Materials Lab involves a series of steps that were all carried out manually in the past. A LABVIEW program has been written to carry out automated sputter deposition of Mo back contact, CuGa, In metallic precursors on a soda lime glass substrate using a stepper motor control for better uniformity. Further, selenization/ sulfurization of these precursors was carried out using rapid thermal processing (RTP). …

Oceanic Rain Identification Using Multifractal Analysis Of Quikscat Sigma-0, Vasud Ganesh Torsekar

Electronic Theses and Dissertations

The presence of rain over oceans interferes with the measurement of sea surface wind speed and direction from the Sea Winds scatterometer and as a result wind measurements contain biases in rain regions. In past research at the Central Florida Remote Sensing Lab, it has been observed that rain has multi-fractal behavior. In this report we present an algorithm to detect the presence of rain so that rain regions are flagged. The forward and aft views of the horizontal polarization σ0 are used for the extraction of textural information with the help of multi-fractals. A single negated multi-fractal exponent is …

Robust Video Transmission Based On Multiple Description Scalable Coding With Erec, Haifeng Zheng, Lun Yu, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

This paper presents a multiple description scalable video coding scheme based on overcomplete motion compensated temporal filtering, named MD-OMCTF, for robust video transmission over wireless and packet loss networks. The intrinsic nature of the structure of OMCTF and embedded coding with modified SPIHT algorithm enable us to provide fully scalable properties for the proposed scheme. We show that multiple description coding is very effective in combating with channel failures in both Internet and wireless video. The integration of MD with OMCTF allows us to achieve both loss resilience and complete scalability. In order to further improve error-resilience to channel bit …

Transform Techniques And Non-Stationarity With An Emphasis On Network Applications, Phat Piron

LSU Master's Theses

The recent years brought a phenomenal development of Internet. It is, therefore, important to find some ways to improve the performances. The first step in this direction is the characterization and modeling of the network traffic. It has been tested that the network traffic behaves like a self-similar process, while packets interarrivals time possess the long-range dependence property. In particular, we model them by using fractional Brownian motion and fractional Gaussian noise, respectively. Note that, the former is just the cumulative sum of the latter. By using these concepts, the traffic characterization reduces to the estimation of one value: the …

An Explicit Mapping Between The Frequency Domain And The Time Domain Representations Of Nonlinear Systems, Marissa Condon, Rossen Ivanov

Articles

Explicit expressions are presented that describe the input-output behaviour of a nonlinear system in both the frequency and the time domain. The expressions are based on a set of coefficients that do not depend on the input to the system and are universal for a given system. The anharmonic oscillator is chosen as an example and is discussed for different choices of its physical parameters. It is shown that the typical approach for the determination of the Volterra Series representation is not valid for the important case when the nonlinear system exhibits oscillatory behaviour and the input has a pole …

Target Tracking In Wireless Sensor Networks, Tarun Anand Malik

LSU Master's Theses

The problem being tackled here relates to the problem of target tracking in wireless sensor networks. It is a specific problem in localization. Localization primarily refers to the detection of spatial coordinates of a node or an object. Target tracking deals with finding spatial coordinates of a moving object and being able to track its movements. In the tracking scheme illustrated, sensors are deployed in a triangular fashion in a hexagonal mesh such that the hexagon is divided into a number of equilateral triangles. The technique used for detection is the trilateration technique in which intersection of three circles is …

Improved Watermarking Scheme Using Decimal Sequences, Naveed Shaik Ashfaq

LSU Master's Theses

This thesis improves upon the work carried out by Mandhani on decimal sequence watermarking showing that the embedding and decoding algorithms used by Mandhani are not robust. We next specify improvements to these algorithms so that the peak signal to noise ratio (PSNR) is maximized and the distortion introduced in the image due to the embedding is minimized. By exploiting the cross correlation property of decimal sequences, the concept of embedding more than one watermark in the same cover image has been investigated. A comparison between the PSNRs for decimal sequence watermarking and other pseudorandom sequences has been made.

Scalable Schemes Against Distributed Denial Of Service Attacks, Kishori Nanduri

LSU Master's Theses

Defense against Distributed Denial of Service (DDoS) attacks is one of the primary concerns on the Internet today. DDoS attacks are difficult to prevent because of the open, interconnected nature of the Internet and its underlying protocols, which can be used in several ways to deny service. Attackers hide their identity by using third parties such as private chat channels on IRC (Internet Relay Chat). They also insert false return IP address, spoofing, in a packet which makes it difficult for the victim to determine the packet's origin. We propose three novel and realistic traceback mechanisms which offer many advantages …

High-Freequency Cmos Vlsi Chip Testability And On-Chip Interconnect Modeling, Evan Ross Shultz

LSU Master's Theses

As high-speed digital and radio-frequency mixed-signal integrated circuits become increasingly common in product designs in industry, it is important for VLSI designers to be familiar with the challenges of chip testing and the behavior of circuit elements, including on-chip interconnect, at high frequencies. Expensive, specialized test equipment and software simulation packages for high-frequency chip testing and design are not always accessible for student research. This thesis documents the setup and characterization of a best-possible environment for high-frequency chip testing and data acquisition using existing laboratory equipment and resources. Experimental methodologies and measurement results of on-chip interconnect signal integrity and delay, …

Graphical Pilot Interface Simulator (Gpis), Jeffry Jorge Handal

LSU Master's Theses

The thesis develops a graphic interface for a dynamic system simulation implemented in the SIMULINK environment. The dynamic system is a B747-200 modeled as a rigid body with six degrees of freedom. The equations and database of aerodynamic coefficients over the complete flight envelope were provided by NASA’s Langley Research Center for the research project “Aircraft Safety: Managing Control Upsets.” The purpose of the interface is to allow the user to “fly the plane from the keyboard;” i.e., interact with the simulation by manipulating, from the keyboard, the main control surfaces and engine thrust and observing the performance of the …

Power System Optimization And Coordination Of Damping Controls By Series Facts Devices, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Reactive Power And Voltage Control Of The Nigerian Grid System Using Micro-Genetic Algorithm, Ganesh K. Venayagamoorthy, G. A. Bakare, U. O. Aliyu

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a micro-genetic based approach to the optimization of reactive power and voltage profiles improvement and real power loss minimization is presented. The reactive power control devices such as generators, tap positions of on-load tap changer of transformers, shunt reactors are used to correct voltage limits violations while simultaneously reducing the system real power losses. Genetic algorithms (GAs) are well-known global search techniques anchored on the mechanisms of natural selection and genetics. Because of the time intensive nature of the conventional GA, the micro-GA is proposed as a more time efficient alternative. The feasibility and effectiveness of the …

Energy-Efficient Self-Organization Protocols For Sensor Networks, Qingwen Xu

Computer Science Theses & Dissertations

A Wireless Sensor Network (WSN, for short) consists of a large number of very small sensor devices deployed in an area of interest for gathering and delivery information. The fundamental goal of a WSN is to produce, over an extended period of time, global information from local data obtained by individual sensors. The WSN technology will have a significant impact on a wide array of applications on the efficiency of many civilian and military applications including combat field surveillance, intrusion detection, disaster management among many others. The basic management problem in the WSN is to balance the utility of the …

Blind Multiridge Detection And Reconstruction Using Ultrasonic Signals, Rekha Katragadda

LSU Master's Theses

Time-frequency signal analysis has been widely applied in the modern radar, acoustic, sonar and ultrasonic signal processing techniques. Recently, the nondestructive testing (NDT) techniques via the ultrasonic instrumentation have shown the striking capability of the quality control for the material fabrication industry. In this thesis, we first provide a general mathematical model for the ultrasonic signals collected by pulse-echo sensors and then design a totally blind, novel, signal processing NDT technique relying on neither a priori signal information nor any manual effort. The signature signal can be blindly extracted by using the automatic optimal frame size selection for further modeling …

Comparative Analysis Of Conventional And Ici-Self-Cancellation Digital Video Broadcasting Transceivers, Khaled Z. Matarneh

LSU Master's Theses

Digital video broadcasting–terrestrial (DVB-T) is one of the important technologies in the communication area because of its capability of high data-rate multimedia transmission. Orthogonal frequency division multiplexing (OFDM) has been the backbone technique in the current DVB-T systems adopted by Europe and Japan. However, since the OFDM system is very sensitive to the frequency synchronization and phase errors, which will induce the intercarrier interference (ICI), the ongoing research has been dedicated to this ICI problem in the presence of the Doppler frequency drift and the fading channels. A means to deal with the ICI problem is called the ICI self-cancellation …

Effect Of Multiuser Interference On Subscriber Location In Cdma Networks, Rohit Sharma

LSU Master's Theses

The last few years have witnessed an ever growing interest in the field of mobile location systems for cellular systems. The motivation is the series of regulations passed by Federal Communications Commission, requiring that wireless service providers support a mobile telephone callback feature and cell site location mechanism. A further application of the location technology is in the rapidly emerging field of intelligent transportation systems, which are intended to enhance highway safety, location based billing etc. Many of the existing location technologies use GPS and its derivatives which require a specialized subscriber equipment. This is not feasible for popular use, …

Laterally Movable Gate Field Effect Transistor (Lmgfet) For Microsensor And Microactuator Applications, In-Hyouk Song

LSU Doctoral Dissertations

Laterally Movable Gate Field Effect Transistor (LMGFET) invented at LSU as a microactuator is the subject of study in this research. The gate moving in lateral direction in a LMGFET changes channel width but keeps the channel length and the gap between the metal gate and the gate oxide constant. LMGFET offers linear change in drain current with gate motion and a large displacement range. This research is the first demonstration of LMGFET. In this dissertation, a post-IC LIGA-like process for LMGFET microstructure fabrication has been developed that is compatible with monolithic integration with CMOS circuitry. A two-mask post-IC process …

Ternary Logic To Binary Bit Conversion Using Multiple Input Floating Gate Mosfets In 0.5 Micron N-Well Cmos Technology, Sowmya Subramanian

LSU Master's Theses

In the present work, a CMOS ternary to binary bit conversion technique has been proposed using multiple input floating gate MOSFETs. The proposed circuit has been implemented in 0.5 µm n-well CMOS technology. The ternary input signals of {-1, 0, +1} are represented as -3 V, 0 V and +3 V, respectively. The ternary input is given as a combination of any two of the three voltage levels and the 4-bit binary output is generated in which the left most bit is sign bit (SB) followed by most significant bit (MSB), second significant bit (SSB) and the least significant bit …

Knowledge-Based Fault Detection Using Time-Frequency Analysis, Venkata S. Vongala

LSU Master's Theses

This work studies a fault detection method which analyzes sensor data for changes in their characteristics to detect the occurrence of faults in a dynamic system. The test system considered in this research is a Boeing-747 aircraft system and the faults considered are the actuator faults in the aircraft. The method is an alternative to conventional fault detection method and does not rely on analytical mathematical models but acquires knowledge about the system through experiments. In this work, we test the concept that the energy distribution of resolution than the windowed Fourier transform. Verification of the proposed methodology is carried …

Object Tracking Using Log-Polar Transformation, Saikiran Sri Thunuguntla

LSU Master's Theses

In this thesis, we use log-polar transform to solve object tracking. Object tracking in video sequences is a fundamental problem in computer vision. Even though object tracking is being studied extensively, still some challenges need to be addressed, such as appearance variations, large scale and rotation variations, and occlusion. We implemented a novel tracking algorithm which works robustly in the presence of large scale changes, rotation, occlusion, illumination changes, perspective transformations and some appearance changes. Log-polar transformation is used to achieve robustness to scale and rotation. Our object tracking approach is based on template matching technique. Template matching is based …

Soft-Decision Equalization Techniques For Frequency Selective Mimo Channels, Shoumin Liu

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

Multi-input multi-output (MIMO) technology is an emerging solution for high data rate wireless communications. We develop soft-decision based equalization techniques for frequency selective MIMO channels in the quest for low-complexity equalizers with BER performance competitive to that of ML sequence detection.

We first propose soft decision equalization (SDE), and demonstrate that decision feedback equalization (DFE) based on soft-decisions, expressed via the posterior probabilities associated with feedback symbols, is able to outperform hard-decision DFE, with a low computational cost that is polynomial in the number of symbols to be recovered, and linear in the signal constellation size. Building upon the probabilistic …

Interference Suppression And Parameter Estimation In Wireless Communication Systems Over Time-Varing Multipath Fading Channels, Jianqiang He

LSU Doctoral Dissertations

This dissertation focuses on providing solutions to two of the most important problems in wireless communication systems design, namely, 1) the interference suppression, and 2) the channel parameter estimation in wireless communication systems over time-varying multipath fading channels. We first study the interference suppression problem in various communication systems under a unified multirate transmultiplexer model. A state-space approach that achieves the optimal realizable equalization (suppression of inter-symbol interference) is proposed, where the Kalman filter is applied to obtain the minimum mean squared error estimate of the transmitted symbols. The properties of the optimal realizable equalizer are analyzed. Its relations with …