Electrical and Electronics Commons^™

Em-Based Iterative Channel Estimation And Sequence Detection For Space-Time Coded Modulation, Zbigniew Baranski

Dissertations

Reliable detection of signals transmitted over a wireless communication channel requires knowledge of the channel estimate. In this work, the application of expectationmaximization (EM) algorithm to estimation of unknown channel and detection of space-time coded modulation (STCM) signals is investigated. An STCM communication system is presented which includes symbol interleaving at the transmitter and iterative EM-based soft-output decoding at the receiver. The channel and signal model are introduced with a quasi-static and time-varying Rayleigh fading channels considered to evaluate the performance of the communication system. Performance of the system employing Kalman filter with per-survivor processing to do the channel estimation …

On Chip Implement Of Deadlock Avoidance In Wormhole Networks, Kiran K. Gururaj

Theses

This thesis gives a detailed description of the Application Specific Integrated Circuit (ASIC) design to avoid deadlocks in Wormhole Networks. Deadlock avoidance is the most critical issue while considering wormhole networks and should be avoided by any routing protocol and algorithm. A novel architecture for the Turn Prohibition Based Routing (TPBR) protocol has been proved to be efficient and was developed as a part of this work. This architecture for implementing the algorithm is divided into three parts. The first part determines the order of selccuon of the nodes, in the network to run the algorithm. The second part deals …

Theory And Design Of Mixed Lumped-Distributed Cross-Coupled Filters With Applications To Linear Phase Shifter And Tunable Filters, Sanghoon Shin

Dissertations

Using cross-coupled networks of a new concept, transmission zeros were efficiently located in the complex frequency-domain. With this approach, the group delay and attenuation slope of the circuit network can be controlled to get both sharp rejection characteristics and linear phase slopes. In order to achieve this performance, various types of combline filters are suggested. Various simulation tools (commercial linear circuit and E-M simulators), as well as the developed pole-zero locator program, were used to design a new class of cross-coupled networks. In particular, the polezero locator program can be used to extract an equivalent circuit of the topology that …

Experimental Studies Of Wave Propagation In Three-Dimensional Photonic Crystals, John M. Tobias

Dissertations

Photonic crystals were proposed fifteen years ago. Propagation is selectively prevented through these crystals resulting in a photonic band gap, that is, a frequency region where light cannot propagate. These frequency bands are analogous to electronic band gaps in solid-state crystals.

The optical properties of the photonic crystal in regions near the band gap remain relatively unexplored. Yet, there is significant evidence to suggest that this avenue of investigation can provide useful optical and microwave applications. Numerical studies have predicted that the effective permittivity near the photonic band gap approaches zero and becomes negative. Selfcollimation of the propagating beam and …

Stereo Matching Algorithm By Propagation Of Correspondences And Stereo Vision Instrumentation, Peerajak Witoonchart

Theses

A new image processing method is described for measuring the 3-D coordinates of a complex, biological surface. One of the problems in stereo vision is known as the accuracy-precision tradeoff problem. This thesis proposes a new method that promises to solve this problem. To do so, two issues are addressed. First, stereo vision instrumentation methods are described. This instrumentation includes a camera system as well as camera calibration, rectification, matching and triangulation. Second, the approach employs an array of cameras that allow accurate computation of the depth map of a surface by propagation of correspondences through pair-wise camera views.

The …

Recent Advances In Silicon Light Emitting Diodes, Aravind Balakrishnan

Theses

A silicon based light emitting diode (LED) is a new gateway for combining optoelectronics with CMOS integrated circuits. The choice of silicon is limited due to its indirect band gap nature. There are new approaches for improving emission efficiencies in Si-LED to nearly 1% at room temperature. Boron implantation has been employed to introduce dislocation array and as a p-type dopant to form p-n Junction in an n-type Si substrate. The device operates as a conventional LED under forward bias. The temperature dependence of radiative recombination rate is addressed by Varshni empirical formula. The difference between the energy at which …

Determination Of Phase Composition Of Sputtered Tantalum On Steel Substrates By Resistivity Measurements, Younes Abbassi

Theses

The objective of this thesis was to develop a method of distinguishing between alpha and beta phases of tantalum films on steel substrates, using the four-point probe resistivity measurements. While there is a large difference between resistivities of the two Ta phases, the problem is challenging because the measurements are influenced by the low resistivity of steel.

For reference, the resistivity measurements of tantalum coatings (1-20 μm) on silicon and silicon dioxide substrates were conducted first. The measured resistivities were related to the crystallographic phase composition of Ta, which has lower resistivity in bcc form, α-phase, (13.5 to 42 μΩcm), …

On Performance Analysis And Implementation Issues Of Iterative Decoding For Graph Based Codes, Xuefei Wei

Dissertations

There is no doubt that long random-like code has the potential to achieve good performance because of its excellent distance spectrum. However, these codes remain useless in practical applications due to the lack of decoders rendering good performance at an acceptable complexity. The invention of turbo code marks a milestone progress in channel coding theory in that it achieves near Shannon limit performance by using an elegant iterative decoding algorithm. This great success stimulated intensive research oil long compound codes sharing the same decoding mechanism. Among these long codes are low-density parity-check (LDPC) code and product code, which render brilliant …

On The Data Hiding Theory And Multimedia Content Security Applications, Litao Gang

Dissertations

This dissertation is a comprehensive study of digital steganography for multimedia content protection. With the increasing development of Internet technology, protection and enforcement of multimedia property rights has become a great concern to multimedia authors and distributors. Watermarking technologies provide a possible solution for this problem.

The dissertation first briefly introduces the current watermarking schemes, including their applications in video,, image and audio. Most available embedding schemes are based on direct Spread Sequence (SS) modulation. A small value pseudo random signature sequence is embedded into the host signal and the information is extracted via correlation. The correlation detection problem is …

Renegotiation Based Dynamic Bandwidth Allocation For Selfsimilar Vbr Traffic, Zafer Sahinoglu

Dissertations

The provision of QoS to applications traffic depends heavily on how different traffic types are categorized and classified, and how the prioritization of these applications are managed. Bandwidth is the most scarce network resource. Therefore, there is a need for a method or system that distributes an available bandwidth in a network among different applications in such a way that each class or type of traffic receives their constraint QoS requirements.

In this dissertation, a new renegotiation based dynamic resource allocation method for variable bit rate (VBR) traffic is presented. First, pros and cons of available off-line methods that are …

Qos Routing Source Routing Problems And Solutions, Ye Tian

Theses

The notion of Quality-of-Service has been proposed to capture qualitatively or quantitatively defined performance contracts between the service provider and the user applications. Integrated network services are designed to support Quality-of-Service (QoS). One of the primary goals for the integrated network services is to find the paths that satisfy given QoS requirements, namely QoS routing. The challenging issue in this area is to route packets subjected to multiple uncorrelated constraints because the problem is inherently NP-complete. This thesis studies the source routing heuristic approaches that bring the time complexity down to the polynomial-time for the multi-constrained path (MCP) problem. A …

Hyperbolic Position Location Estimator With Tdoas From Four Stations, Sreeram Potluri

Theses

This thesis presents a detailed derivation of a set of equations needed to locate the three dimensional position of a mobile given the locations of four fixed stations (like a global positioning system (GPS) satellite or a base station in a cell) and the signal time of arrival (TOA) from the mobile to each station. From these derived equations, a synthesizable VHDL model was developed and simulated using IEEE numen*c_std package. All the inputs and outputs were described by 32 bit vectors. From the simulations, it was observed that in the best case the mobile position was off by I …

Arq Protocol For Joint Source And Channel Coding And Its Applications, Bin He

Dissertations

Shannon's separation theorem states that for transmission over noisy channels, approaching channel capacity is possible with the separation of source and channel coding. Practically, the situation is different. Infinite size blocks are needed to achieve this theoretical limit. Also, time-varying channels require a different approach. This leads to many approaches for source and channel coding. This dissertation will address a joint source and channel coding that suits Automatic Repeat Request (ARQ) application and applies it to packet switching networks. Following aspects of the proposed joint source and channel coding approach will be presented:

1. The design of the proposed joint source …

Saturation Routing For Asynchronous Transfer Mode (Atm) Networks, Jose Luis Ucles

Dissertations

The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that …

Turbo Space-Time Coded Modulation : Principle And Performance Analysis, Dongzhe Cui

Dissertations

A breakthrough in coding was achieved with the invention of turbo codes. Turbo codes approach Shannon capacity by displaying the properties of long random codes, yet allowing efficient decoding. Coding alone, however, cannot fully address the problem of multipath fading channel. Recent advances in information theory have revolutionized the traditional view of multipath channel as an impairment. New results show that high gains in capacity can be achieved through the use of multiple antennas at the transmitter and the receiver. To take advantage of these new results in information theory, it is necessary to devise methods that allow communication systems …

Scheduling Algorithms For High-Speed Switches, Jinhui Li

Dissertations

The virtual output queued (VOQ) switching architecture was adopted for high speed switch implementation owing to its scalability and high throughput. An ideal VOQ algorithm should provide Quality of Service (QoS) with low complexity. However, none of the existing algorithms can meet these requirements.

Several algorithms for VOQ switches are introduced in this dissertation in order to improve upon existing algorithms in terms of implementation or QoS features. Initially, the earliest due date first matching (EDDFM) algorithm, which is stable for both uniform and non-uniform traffic patterns, is proposed. EDDFM has lower probability of cell overdue than other existing maximum …

2d And 3d Surface Image Processing Algorithms And Their Applications, Jianlin Gao

Dissertations

This doctoral dissertation work aims to develop algorithms for 2D image segmentation application of solar filament disappearance detection, 3D mesh simplification, and 3D image warping in pre-surgery simulation. Filament area detection in solar images is an image segmentation problem. A thresholding and region growing combined method is proposed and applied in this application. Based on the filament area detection results, filament disappearances are reported in real time. The solar images in 1999 are processed with this proposed system and three statistical results of filaments are presented.

3D images can be obtained by passive and active range sensing. An image registration …

Channel Estimation And Signal Enhancement For Ds-Cdma Systems, Kun Wang

Dissertations

This dissertation focuses on topics of Bayesian-based multiuser detection, space-time (S-T) transceiver design, and S-T channel parameter estimation for direct-sequence code-division multiple-access (DS-CDMA) systems.

Using the Bayesian framework, various linear and simplified nonlinear multiuser detectors are proposed, and their performances are analyzed. The simplified non-linear Bayesian solutions can bridge the performance gap between sub-optimal linear multiuser detectors and the optimum multiuser detector.

To further improve the system capacity and performance, S-T transceiver design approaches with complexity constraint are investigated. Novel S-T receivers of low-complexity that jointly use the temporal code-signature and the spatial signature are proposed. Our solutions, which lead …

Modeling, Design And Scheduling Of Computer Integrated Manufacturing And Demanufacturing Systems, Ying Tang

Dissertations

This doctoral dissertation work aims to provide a discrete-event system-based methodology for design, implementation, and operation of flexible and agile manufacturing and demanufacturing systems. After a review of the current academic and industrial activities in these fields, a Virtual Production Lines (VPLs) design methodology is proposed to facilitate a Manufacturing Execution System integrated with a shop floor system. A case study on a back-end semiconductor line is performed to demonstrate that the proposed methodology is effective to increase system throughput and decrease tardiness. An adaptive algorithm is proposed to deal with the machine failure and maintenance. To minimize the environmental …

Joint Source Channel Coding For Progressive Image Transmission, Minyi Zhao

Dissertations

Recent wavelet-based image compression algorithms achieve best ever performances with fully embedded bit streams. However, those embedded bit streams are very sensitive to channel noise and protections from channel coding are necessary. Typical error correcting capability of channel codes varies according to different channel conditions. Thus, separate design leads to performance degradation relative to what could be achieved through joint design. In joint source-channel coding schemes, the choice of source coding parameters may vary over time and channel conditions. In this research, we proposed a general approach for the evaluation of such joint source-channel coding scheme. Instead of using the …

Novel Multiuser Detection And Multi-Rate Schemes For Multi-Carrier Cdma, Pingping Zong

Dissertations

A large variety of services is [sic] expected for wireless systems, in particular, high data rate services, such as wireless Internet access. Users with different data rates and quality of service (QoS) requirements must be accommodated. A suitable multiple access scheme is key to enabling wireless systems to support both the high data rate and the integrated multiple data rate transmissions with satisfactory performance and flexibility. A multi-carrier code division multiple access (MC-CDMA) scheme is a promising candidate for emerging broadband wireless systems. MC-CDMA is a hybrid of orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA). The …

Plasma Induced Damage To Si And Sige Devices And Materials, Wei Zhong

Dissertations

This thesis studied the plasma-induced damage to Si and strained Si_1-xGe_x, and the resulting change in device characteristics. The energetic particles (ions, electrons and photons) in plasma reactor present a potentially hostile environment for processing VLSI devices. An inductively coupled plasma (ICP) reactor was used to study its damage effects to thin gate oxides. Electrical characterizations by C-V, ramped voltage breakdown (RVB) and deep-level transient spectroscopy (DLTS) measurement, and x-ray photoelectron spectroscopy (XPS) analysis were employed to investigate the damages to thin gate oxides and Si/SiO₂ interface. The shift of flat band voltage, the reduction …

Performance Analysis And Resource Allocation In Cdma Wireless Networks For Multimedia Services, Sebnem Zorlu

Dissertations

The proliferation of Internet and demand for wireless services necessitate large increases in capacity and data rates in order to support different multimedia services. Wireless systems will be required to support sources with a variety of traffic characteristics and quality of service requirements. This requires algorithms for admission control and resource allocation at the session, burst and packet levels. The purpose of this research is to develop and analyze optimal resource allocation strategies to maximize throughput of wireless systems with integrated services. Given the multimedia user requirements, the problem addressed can be formulated as a constrained optimization problem. The objective …

Buffer Management And Cell Switching Management In Wireless Packet Communications, Jongho Bang

Dissertations

The buffer management and the cell switching (e.g., packet handoff) management using buffer management scheme are studied in Wireless Packet Communications.

First, a throughput improvement method for multi-class services is proposed in Wireless Packet System. Efficient traffic management schemes should be developed to provide seamless access to the wireless network. Specially, it is proposed to regulate the buffer by the "Selective- Delay Push-In (SDPI)" scheme, which is applicable to scheduling delay-tolerant non-real time traffic and delay-sensitive real time traffic. Simulation results show that the performance observed by real time traffics are improved as compared to existing buffer priority scheme in …

Design Of Traffic Shaper / Scheduler For Packet Switches And Diffserv Networks : Algorithms And Architectures, Surong Zeng

Dissertations

The convergence of communications, information, commerce and computing are creating a significant demand and opportunity for multimedia and multi-class communication services. In such environments, controlling the network behavior and guaranteeing the user's quality of service is required. A flexible hierarchical sorting architecture which can function either as a traffic shaper or a scheduler according to the requirement of the traffic load is presented to meet the requirement. The core structure can be implemented as a hierarchical traffic shaper which can support a large number of connections with a wide variety of rates and burstiness without the loss of the granularity …

Optical Properties Of Photonic Crystals, Anand G. Shenoy

Theses

The ability to confine light in three dimensions has important implications for quantum optics and quantum-optical devices. Photonic crystals, the optical analog of electronic crystals, provide us a means of achieving this goal. This analogy has motivated a whole new series of experimental and theoretical searches for elusive photonic band-gap structures. Combinations of metallic and dielectric materials can be used to obtain the required three-dimensional (3D) periodic variation in the dielectric constant. This could pave the way for photonic crystal structures that have widespread applications.

The working of 3D photonic crystals into the wavelength regimes where most optoelectronic devices operate, …

Propagation And Scattering Of Collimated Beam Wave In Vegetation Using Scalar Transport Theory, Michael Yu-Chi Wu

Theses

The scalar time-dependent equation of radiative transfer is used to develop a theory of pulse beamwave propagation and scattering in a medium character ized by many random discrete scatterers which scatter energy strongly in the forward scattering direction. Applications include the scattering of highly collimated millimeter waves in vegetation and optical beams in the atmosphere. The specific problem analyzed is that of a periodic sequence of Gaussian shaped pulses normally incident from free space onto the planar boundary surface of a random medium half-space, such as a forest, that possesses a power scatter (phase) function consisting of a strong, narrow …

Video Indexing And Summarization Using Motion Activity, Kadir Askin Peker

Dissertations

In this dissertation, video-indexing techniques using low-level motion activity characteristics and their application to video summarization are presented. The MPEG-7 motion activity feature is defined as the subjective level of activity or motion in a video segment. First, a novel psychophysical and analytical framework for automatic measurement of motion activity in compliance with its subjective perception is developed. A psychophysically sound subjective ground truth for motion activity and a test-set of video clips is constructed for this purpose. A number of low-level, compressed domain motion vector based, known and novel descriptors are then described. It is shown that these descriptors …

Phase-Locked Loop, Delay-Locked Loop, And Linear Decorrelating Detector For Asynchronous Multirate Ds-Cdma System, Sok-Kyu Lee

Dissertations

The performance of phase synchronization and code tracking of a digital phase-locked loop (PLL) and delay-locked loop (DLL), respectively, is investigated in wideband asynchronous multirate DS-CDMA system. Dynamic Partial Correlation (DPC) method is proposed to evaluate the autocorrelation and its power spectrum density (PSD) of the cross-correlated terms in the presence of multirate multiple access interference (MMAI) under additive white gaussian noise (AWGN) and fading channel environments. The steady-state probability density function (PDF) and variance of the phase estimator error and code tracking jitter is evaluated by solving the first-order Fokker-Planck equation.

Among many linear multiuser detectors which decouple the …

Resource Allocation For Cdma Downlink To Achieve Maximum Throughput, Anil Bircan

Dissertations

Growing interest in cellular phones, wireless modems, instant messaging, pagers with the increasing use of the Internet in daily life indicate that wireless high speed Internet access and wireless multimedia applications are in great demand. The barrier to satisfy this demand is the provision of sufficiently high bit rates in severe wireless mobile channel conditions, for a multitude of services, each requiring different and perhaps even time-varying quality of services (QoS) that can be more demanding than the QoS required by today's voice service. New generation systems will enable provision of a multitude of services each with different QoS and …