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Articles 301 - 330 of 1111

Full-Text Articles in Electrical and Electronics

Nonlinear Optical Properties Of Nano Structures, Mahesh U. Ajgaonkar Jan 2001

Nonlinear Optical Properties Of Nano Structures, Mahesh U. Ajgaonkar

Dissertations

Nonlinear optical properties of nanoscale semiconductors had been a topic of intense research in recent years in attempts to realize all-optical communication systems. These semiconductor nanoclusters, in the range of 1-100nm are hosted in a dielectric material and are considered as a particular example of Conditional Artificial Dielectric (CAD). It has been reported that the dielectric properties of such materials will be greatly changed by light intensity.

Two main paths to realize nano semiconductor clusters are reported in this dissertation. The Pulsed Laser Deposition (PLD) technique is first described. Here we were investigating the effect of surface modification of nano …


Interference Suppression And Diversity For Cdma Systems, Xiaodong Cai Jan 2001

Interference Suppression And Diversity For Cdma Systems, Xiaodong Cai

Dissertations

In code-division multiple-access (CDMA) systems, due to non-orthogonality of the spreading codes and multipath channels, the desired signal suffers interference from other users. Signal fading due to multipath propagation is another source of impairment in wireless CDMA systems, often severely impacting performance. In this dissertation, reduced-rank minimum mean square error (MMSE) receiver and reduced-rank minimum variance receiver are investigated to suppress interference; transmit diversity is applied to multicarrier CDMA (MC-CDMA) systems to combat fading; packet combing is studied to provide both interference suppression and diversity for CDMA random access systems.

The reduced-rank MMSE receiver that uses a reduced-rank estimated covariance …


Analysis And Control Of Monolithic Piezoelectric Nano-Actuator, Xuemei Sun Jan 2001

Analysis And Control Of Monolithic Piezoelectric Nano-Actuator, Xuemei Sun

Dissertations

The study of the monolithic piezoelectric actuator, the dominant type of micropositioner is an attractive and challenging area, where realtime control theory and digital signal processing are effectively applied. The actuator can be applied in precision instruments and precision control, such as microscopes, medical and optics instruments because of the piezoelectric ceramic's high resolution, fast transient response, and potential low cost. However, hysteresis nonlinearity and lightly damped vibration exist in the system, which limit the actuator applications.

This work focuses on the hysteresis characteristics in time and frequency domains along with experimental and simulated results to verify the effectiveness of …


Object Detection And Activity Recognition In Digital Image And Video Libraries, Ibrahim Burak Ozer Jan 2001

Object Detection And Activity Recognition In Digital Image And Video Libraries, Ibrahim Burak Ozer

Dissertations

This thesis is a comprehensive study of object-based image and video retrieval, specifically for car and human detection and activity recognition purposes. The thesis focuses on the problem of connecting low level features to high level semantics by developing relational object and activity presentations. With the rapid growth of multimedia information in forms of digital image and video libraries, there is an increasing need for intelligent database management tools. The traditional text based query systems based on manual annotation process are impractical for today's large libraries requiring an efficient information retrieval system. For this purpose, a hierarchical information retrieval system …


A Study And Some Experimental Work Of Digital Image And Video Watermarking, Tsui-Feng Liu Jan 2001

A Study And Some Experimental Work Of Digital Image And Video Watermarking, Tsui-Feng Liu

Theses

The rapid growth of digitized media and the emergence of digital networks have created a pressing need for copyright protection and anonymous communications schemes. Digital watermarking (or data hiding in a more general term) is a kind of steganography technique by adding information into a digital data stream. Several most important watermarking schemes applied to multilevel and binary still images and digital videos were studied. They include schemes based on DCT (Discrete Cosine Transform), DWT (Discrete Wavelet Transform), and fractal transforms. The question whether these invisible watermarking techniques can resolve the issue of rightful ownership of intellectual properties was discussed. …


An Efficient Expression Of The Timestamp And Period In Packet-And Cell-Based Schedulers, Dong Wei Jan 2001

An Efficient Expression Of The Timestamp And Period In Packet-And Cell-Based Schedulers, Dong Wei

Theses

Scheduling algorithms are implemented in hardware in high-speed switches to provide Quality-of-Service guarantees in both cell-based and packet-based networks. Being able to guarantee end-to-delay and fairness, timestamp-based fair queuing algorithms, which include SCFQ, WFQ, WF2Q and WF2Q+, have received much attention in the past few years. In timestamp-based fair queuing algorithms, the size of timestamp and period determines the supportable rates in terms of the range and accuracy. Furthermore, it also determines the scheduler's memory in terms of offchip bandwidth and storage space. An efficient expression can reduce the size of the timestamp and period without compromising the accuracy. In …


Highway Advisory Radio In The State Of New Jersey, Thomas Mark Nemeth Jan 2001

Highway Advisory Radio In The State Of New Jersey, Thomas Mark Nemeth

Theses

Highway Advisory Radio (HAR) is a broadcasting system used by transportation agencies to disseminate vital real-time traffic information to motorists. Each transmitter is restricted by the rules and regulations of the Federal Communications Commission (FCC) to an average broadcast radius of three to five miles. Most commonly these transmitters are located at major highway intersections, such that motorists may take alternate routes in case of congestion or emergencies.

All operational HAR transmitters in New Jersey were identified and their coverage zones were quantitatively characterized in terms of the signal to noise ratio at the receiver. These experimental results were then …


Reduction Of Peak To Average Power Ratio In Ofdm And Ofdm-Cdma System, Jie Cheng Aug 2000

Reduction Of Peak To Average Power Ratio In Ofdm And Ofdm-Cdma System, Jie Cheng

Theses

High Peak to Average Power Ratio is a main problem in Orthogonal Frequency Division Multiplexing(OFDM) system and Orthogonal Frequency Division Multiplexing -Code Division Multiple Access (OFDM-CDMA) system. Considering a compensated High Power Amplifier(HPA), in order to keep linearity for amplification, Input Back-Off(IBO) of the HP-A, has to be increased for handling a high PAPR. Higher 1130 will make HPA less efficient. Additionally, a signal with high PAPR will suffer clipping when PAPR is larger than 1130 of the HPA. Clipping can cause the distortion of the signal and deteriorate the performance of the system. Reduction of PAPR is a main …


Phase Tunability In A Conductor Backed Coplanar Waveguide Patch Antenna, Idan Mandelbaum Aug 2000

Phase Tunability In A Conductor Backed Coplanar Waveguide Patch Antenna, Idan Mandelbaum

Theses

Traditionally beam steering in phase array antenna systems is achieved using tunable phase shifters or switched feed networks. Here, a tunable patch antenna element is suggested as a novel alternative to a combination of a radiating element and a phase shifter. A conductor backed coplanar waveguide patch antenna is chosen due to its suitability to mounted external tuning elements, using varactor diodes. Limited types of lumped tuning circuits, using varactor diodes, have been tested, though a lumped as well as distributed tuning is feasible in the chosen antenna configuration. Approximate analytical models for coplanar waveguide patch antennas with finite ground …


Video Traffic Modeling And Delivery, Hai Liu May 2000

Video Traffic Modeling And Delivery, Hai Liu

Dissertations

Video is becoming a major component of the network traffic, and thus there has been a great interest to model video traffic. It is known that video traffic possesses short range dependence (SRD) and long range dependence (LRD) properties, which can drastically affect network performance. By decomposing a video sequence into three parts, according to its motion activity, Markov-modulated self-similar process model is first proposed to capture autocorrelation function (ACF) characteristics of MPEG video traffic. Furthermore, generalized Beta distribution is proposed to model the probability density functions (PDFs) of MPEG video traffic.

It is observed that the ACF of MPEG …


Investigation Of The Baroreflex Of The Rat : Steady State And Dynamic Features, Xiaorui Tang May 2000

Investigation Of The Baroreflex Of The Rat : Steady State And Dynamic Features, Xiaorui Tang

Dissertations

The baroreflex is one of the most important feedback systems in the body to maintain blood pressure variation within the homeostatic range. In this dissertation, the important features of the carotid and aortic baroreflexes have been extensively investigated on ventilated, central nervous system intact, neuromuscular blocked (NMB) rats using different control system and signal processing tools. Studies have demonstrated that sinoaortic denervation (SAD) caused substantial increases in the blood pressure variability. Comparing the pre- and post-SAD blood pressure spectra, there was a significant increase of power in the very low frequency region (0.00195 -0.2 Hz), and a significant decrease of …


Design And Analysis Of A Scalable Terabit Multicast Packet Switch : Architecture And Scheduling Algorithms, Feihong Chen May 2000

Design And Analysis Of A Scalable Terabit Multicast Packet Switch : Architecture And Scheduling Algorithms, Feihong Chen

Dissertations

Internet growth and success not only open a primary route of information exchange for millions of people around the world, but also create unprecedented demand for core network capacity. Existing switches/routers, due to the bottleneck from either switch architecture or arbitration complexity, can reach a capacity on the order of gigabits per second, but few of them are scalable to large capacity of terabits per second.

In this dissertation, we propose three novel switch architectures with cooperated scheduling algorithms to design a terabit backbone switch/router which is able to deliver large capacity, multicasting, and high performance along with Quality of …


Programmable Latching Probe Microstructures For Wafer Testing Applications, Salima Taifa Sadeq May 2000

Programmable Latching Probe Microstructures For Wafer Testing Applications, Salima Taifa Sadeq

Theses

The objective of this thesis is to design a programmable wafer testing array on a single chip based on micro electromechanical systems (MEMS) and VLSI. The wafer-scale integration in this thesis is a programmable array of test probes that are used for engineering test of VLSI and ULSI silicon integrated circuits at the wafer level. This consists of two subsystems (1) the VLSI address circuits used for addressing and controlling the MEMS on the chip and (2) the latching probe MEMS microstructure array that actuates into position for testing VLSI wafers. Each of the subsystems have been designed, analyzed and …


Bounded Beam Wave Pulse Propagation And Scattering In Random Media Based On The Radiative Transfer Theory Using 2-D Gauss Quadrature Formula, Sheng-Kai Hu May 2000

Bounded Beam Wave Pulse Propagation And Scattering In Random Media Based On The Radiative Transfer Theory Using 2-D Gauss Quadrature Formula, Sheng-Kai Hu

Theses

The scalar time-dependent equation of radiative transfer is used to develop a theory of bounded beam wave narrow band pulse propagation and scattering in a medium characterized by many random discrete scatters, which scatters 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 scatter (phase) function consisting of a …


Space/Time/Frequency Methods In Adaptive Radar, Christopher D. Peckham Jan 2000

Space/Time/Frequency Methods In Adaptive Radar, Christopher D. Peckham

Dissertations

Radar systems may be processed with various space, time and frequency techniques. Advanced radar systems are required to detect targets in the presence of jamming and clutter. This work studies the application of two types of radar systems.

It is well known that targets moving along-track within a Synthetic Aperture Radar field of view are imaged as defocused objects. The SAR stripmap mode is tuned to stationary ground targets and the mismatch between the SAR processing parameters and the target motion parameters causes the energy to spill over to adjacent image pixels, thus hindering target feature extraction and reducing the …


Multi-User Detection For Multi-Rate Ds/Cdma Systems, Jinwen Ma Jan 2000

Multi-User Detection For Multi-Rate Ds/Cdma Systems, Jinwen Ma

Dissertations

Wireless cellular communication is witnessing a rapid growth in market, technology and range of services. Current and future demands for wireless communication services motivate the need for handling multi-media traffic types. In a multimedia communication system, users with different and even time-varying rates and quality of services (QoS) requirements, such as voice, image and data, must be accommodated. The use of Spread Spectrum modulation with Code Division Multiple Access (CDMA) technology is an attractive approach for economical spectrally efficient and high quality cellular and personal communication services. This dissertation explores the technologies of applying different interference cancellation techniques to multi-rate …


Integrated Product And Process Development Methodologies For Environmentally Conscious Electronic Products, Pingtao Yan Jan 2000

Integrated Product And Process Development Methodologies For Environmentally Conscious Electronic Products, Pingtao Yan

Dissertations

This research focuses on integrated product and process development (IPPD) methodologies for environmentally conscious electronic products. After a review of current research issues in the field of product and process development, a generic framework for IPPD is proposed which describes most of the concerned issues formally as constrained optimization problems. These problems may include such optimization objectives as cost, benefit, and environmental impact. Based on this framework, an IPPD methodology is proposed as a systems approach to competitive and environmentally conscious product and process development. A case study on personal computer development is performed illustrating how to apply the methodology …


Data Hiding In Multimedia - Theory And Applications, Mahalingam Ramkumar Jan 2000

Data Hiding In Multimedia - Theory And Applications, Mahalingam Ramkumar

Dissertations

Multimedia data hiding or steganography is a means of communication using subliminal channels. The resource for the subliminal communication scheme is the distortion of the original content that can be tolerated. This thesis addresses two main issues of steganographic communication schemes:

1. How does one maximize the distortion introduced without affecting fidelity of the content?

2. How does one efficiently utilize the resource (the distortion introduced) for communicating as many bits of information as possible? In other words, what is a good signaling strategy for the subliminal communication scheme?

Close to optimal solutions for both issues are analyzed. Many techniques …


Experimental Ion Implantation System For Decaborane Ions, Vijay Babaram Jan 2000

Experimental Ion Implantation System For Decaborane Ions, Vijay Babaram

Theses

Future generations of Si technology will require ultra shallow junctions (tens of nm) in the drain and source regions of MOS transistors. Fabrication of such shallow p-type junctions requires implantation of boron at ultra low energies (< 1 keV), below the limits of standard ion implantation technology. A proposed solution involves implantation of B10Hx+ ions in which boron atoms carry less than 10% of the beam energy.

This thesis is a part of the feasibility study of this new technology. An experimental ion implantation system was designed and built at Ion Beam and Thin Film Lab, NJIT. The system was tested and the mass analyzing magnet was calibrated using argon ions. Decaborane ions, …


Editing Mpeg2 Video In Compressed Domain, Ren Egawa Jan 2000

Editing Mpeg2 Video In Compressed Domain, Ren Egawa

Theses

As MPEG2 becomes the heart of most digital video applications, the need to edit an MPEG2 bitstream video in compressed domain has increased. To realize this need, two major technical issues must be resolved: decoder buffer and segment extraction.

In the decoder buffer issue, the edited stream must ensure that the buffer would not overflow or underfiow as the result of the editing. This thesis invented a mathematical model that could describe the editing task and predict the editing effect on the buffer. Based on this model, the thesis then built a method to edit a stream safely. This method …


Detection And Robustness Of Digital Image Watermarking Signals : A Communication Theory Approach, George F. Elmasry Aug 1999

Detection And Robustness Of Digital Image Watermarking Signals : A Communication Theory Approach, George F. Elmasry

Dissertations

The detection and robustness of the watermark signal is studied from a communications point of view. The contributions of this dissertation are presented in two parts. The first part, which covers the detection aspect, introduces a new digital image watermarking approach that embeds meaningful information in a copyright protection watermark signal; demonstrates the need to approach the watermark signal as a power-constrained signal; studies the relationship between the watermark signal dimension and the image capacity to the signal; explains the similarities and differences between detecting the watermark signal and detecting a signal over a spread-spectrum communication channel; and analyzes the …


Emissivity Measurements And Modeling Of Silicon Related Materials, Vijay Krishnamurthy Aug 1999

Emissivity Measurements And Modeling Of Silicon Related Materials, Vijay Krishnamurthy

Theses

The objective of the thesis was to study the radiative properties of silicon related materials for applications in rapid thermal proceesing. In particular, three distinct materials have been considered - Silicon, SIMOX and Tantalum.

The research highlights are Establishment of spectral emissometry as a novel, reliable and reproducible technique for a) Determination of wavelength and temperature dependent reflectivity, transmissivity, emissivity of silicon related materials and structures. The emissometer operates in the wavelength range of 1-20µm and temperature range of 300-1200K. b) Establishment of methodoligies to obtain the frnndemental constants. Effects of wavelength, temperature, total available free carriers by doping types …


Variable Gain Control Of Brushless Dc Motor Control With Low Resolution Sensors, Chung-Hsiang Wang Aug 1999

Variable Gain Control Of Brushless Dc Motor Control With Low Resolution Sensors, Chung-Hsiang Wang

Theses

In this work, feasibility of using low cost, low resolution sensor for high performance brushless dc (BLDC) motor speed control is investigated. Conventional control, using a tachometer or high resolution encoder, suffers from drawbacks such as high cost, large physical volume, and high sensor processing bandwidth. On the other hand, sensorless BLDC motor, appealing in its hardware simplicity, does not provide sufficient fast performance. Using a standard low resolution sensor, such as a hall sensor or commutation encoder, a compromise between cost and performance can be obtained. However, the use of a low resolution sensor does pose a challenge to …


Adaptive Interference Cancelation Techniques For Multicarrier Modulated Systems, Matthijs A. Visser May 1999

Adaptive Interference Cancelation Techniques For Multicarrier Modulated Systems, Matthijs A. Visser

Dissertations

Current wireline systems and wireless broadcasting systems employ multicarrier modulation (MCM). This includes the high-rate digital subscriber line (HDSL), digital audio broadcasting system (DAB) and the digital terrestrial television broadcasting system (dTTb). Multicarrier modulation is also envisioned for high-speed indoor wireless local area networks (WLAN). Additionally, multicarrier code division multiple access (MC-CDMA), a hybrid of orthogonal frequency division multiplexing (OFDM) and CDMA, is proposed for the downlink (base-to-mobile) of a 3rd generation wireless system as part of the IMT-2000 standardization process.

The performance of an MC-CDMA system--similar to a direct sequence CDMA (DS-CDMA) system--is limited by the presence of multiple …


On Scheduling Input Queued Cell Switches, Shizhao Li May 1999

On Scheduling Input Queued Cell Switches, Shizhao Li

Dissertations

Output-queued switching, though is able to offer high throughput, guaranteed delay and fairness, lacks scalability owing to the speed up problem. Input-queued switching, on the other hand, is scalable, and is thus becoming an attractive alternative. This dissertation presents three approaches toward resolving the major problem encountered in input-queued switching that has prohibited the provision of quality of service guarantees.

First, we proposed a maximum size matching based algorithm, referred to as min-max fair input queueing (MFIQ), which minimizes the additional delay caused by back pressure, and at the same time provides fair service among competing sessions. Like any maximum …


On-Line State And Parameter Estimation In Nonlinear Systems, David A. Haessig May 1999

On-Line State And Parameter Estimation In Nonlinear Systems, David A. Haessig

Dissertations

On-line, simultaneous state and parameters estimation in deterministic, nonlinear dynamic systems of known structure is the problem considered. Available methods are few and fall short of user needs in that they are difficult to apply, their applicability is restricted to limited classes of systems, and for some, conditions guaranteeing their convergence don't exist.

The new methods developed herein are placed into two categories: those that involve the use of Riccati equations, and those that do not. Two of the new methods do not use Riccati equations, and each is considered to be a different extension of Friedland' s parameter observer …


Fdtd-Based Full Wave Co-Simulation Model For Hybrid Electromagnetic Systems, Tong Li May 1999

Fdtd-Based Full Wave Co-Simulation Model For Hybrid Electromagnetic Systems, Tong Li

Dissertations

In high-frequency ranges, the present electronic design automation software has limited capabilities to model electromagnetic (EM) systems where there are strong field effects influencing their characteristics. In this situation, a full-wave simulation tool is desired for the analysis and design of high-speed and non-linear EM systems. It is necessary to explore the interaction between the field and electronic components during a transient process when field effects are more significant. The finite-difference time-domain (FDTD) technique receives growing attention in the area of EM system analysis and simulation due to its simplicity, flexibility and robustness. It is a full-wave simulation method that …


Observers For Discrete-Time Nonlinear Systems, Walter D. Grossman May 1999

Observers For Discrete-Time Nonlinear Systems, Walter D. Grossman

Dissertations

Observer synthesis for discrete-time nonlinear systems with special applications to parameter estimation is analyzed. Two new types of observers are developed. The first new observer is an adaptation of the Friedland continuous-time parameter estimator to discrete-time systems. The second observer is an adaptation of the continuous-time Gauthier observer to discrete-time systems. By adapting these observers to discrete-time continuous-time parameter estimation problems which were formerly intractable become tractable.

In addition to the two newly developed observers, two observers already described in the literature are analyzed and deficiencies with respect to noise rejection are demonstrated. improved versions of these observers are proposed …


Dual Frequency Bi-Othogonally Polarized Antennas For Gps Applications, Anand Arun Mahale May 1999

Dual Frequency Bi-Othogonally Polarized Antennas For Gps Applications, Anand Arun Mahale

Theses

Dual frequency bi-orthogonally polarized antenna to be used in Global Positioning System applications operating in Li (1575.42 ± 10.23 MHz) and L2 (1227.60 ± 10.23 MHz) Bands has been studied. To ensure compatibility with existing applications, the antenna size is limited in dimensions to 4.120" x 4.680" x 1.250" including the radome. Orthogonally placed two dual frequency probe excited patches were designed using a high dielectric constant substrate (ε r = 9.8 and thickness of 250 mils, Rogers TMM10i material) to obtain vertical and horizontal polarization for each band. The measured performance of this antenna showed good agreement with the …


A Signal Conditioning Approach For The Extraction Of The Oscillatory Petential From The Electroretinogram, Peter Haines Derr May 1999

A Signal Conditioning Approach For The Extraction Of The Oscillatory Petential From The Electroretinogram, Peter Haines Derr

Theses

The oscillatory potential (OP), a signal component of the electroretinogram (ERG), was investigated to determine correlation of the OP and pathological conditions of the inner retina. Large transients characterize the ERG. Such transients stimulate a filter's natural response. Since these responses can co-occur with the OP, a distorted OP will be extracted. A proposed signal windowing and padding technique for conditioning the ERG signal has been implemented for the extraction of a ntnimally distorted OP.

Windowing is used to capture only the OP period. The windowed ERG signal is then signal conditioned to generate initial values for the filter's state …