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Device and circuit modeling and development of a nonvolatile random access memory cell, utilizing an amorphous silicon thin film floating-gate transistor based technology
Title
Device and circuit modeling and development of a nonvolatile random access memory cell, utilizing an amorphous silicon thin film floating-gate transistor based technology.
Creator
Riggio, Salvatore Richard, Jr., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
High density storage mechanisms are generally created using either magnetic or optical implementation techniques. Both of these techniques require mechanical transport of the medium and, therefore, have low reliability factors. These devices also generate unwanted low level ambient noise, which is of particular concern when considering modern quiet office standards. Additionally, optical techniques tend to be read-only in nature. Both mechanisms exhibit random access times that are measured...
Show moreHigh density storage mechanisms are generally created using either magnetic or optical implementation techniques. Both of these techniques require mechanical transport of the medium and, therefore, have low reliability factors. These devices also generate unwanted low level ambient noise, which is of particular concern when considering modern quiet office standards. Additionally, optical techniques tend to be read-only in nature. Both mechanisms exhibit random access times that are measured in milli-seconds, rather than in micro-seconds. Therefore, the creation of a non-volatile random access memory as a replacement for the above mentioned storage techniques would be of great advantage in terms of access time, reliability, and ambient noise level. Described within are the device and circuit modeling and fabrication techniques used to develop a non-volatile random access memory cell from an amorphous silicon thin-film transistor based technology. Amorphous silicon thin-film transistors are fabricated by depositing the metal, the insulator and the semiconductor materials with a sputtering mechanism in a vacuum at 220 degrees centigrade, rather than by diffusion at 2000 degrees centigrade, as is done with crystalline silicon. By depositing a metal in the insulator, which is located between the gate and the channel, and by using an insulator material with extremely high resistivity, one can store charge in the gate region for a long period of time without external power. For example, this period of time can be as little as one week or as long as over one year. With a periodic refresh, one can extend the memory time of this storage mechanism indefinitely. Thin-film transistors can be deposited on a variety of materials such as glass, quartz or plastic by means of a stationary or continuous motion fabrication system. This material can be either rigid or flexible, and can be comparatively large in size. This allows for much greater circuit density than a standard crystalline silicon chip that contains devices of a comparable channel length. Ten-thousand mega bytes, or more, of virtual storage could become common place. In summary, this approach represents a large scale, high density, high speed "non-volatile" storage device, with read-write random access capability, without moving parts.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/12360
Subject Headings
Random access memory, Thin film devices, Transistors, Semiconductors
Format
Document (PDF)
Enhancing video quality based on psychophysical studies of smooth pursuit eye movements
Title
Enhancing video quality based on psychophysical studies of smooth pursuit eye movements.
Creator
Chilamakuri, Pavani., Florida Atlantic University, Furht, Borko, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
When motion occurs in a scene, the quality of video degrades due to motion smear, which results in a loss of contrast in the image. The characteristics of the human vision system when smooth pursuit eye movements occur are different from those when the eye fixates on an object such as a video screen during motion. Smooth pursuit eye movements dominate in the presence of dynamic stimuli. In the presence of smooth pursuit eye movements, the contrast sensitivity for increasing target velocities...
Show moreWhen motion occurs in a scene, the quality of video degrades due to motion smear, which results in a loss of contrast in the image. The characteristics of the human vision system when smooth pursuit eye movements occur are different from those when the eye fixates on an object such as a video screen during motion. Smooth pursuit eye movements dominate in the presence of dynamic stimuli. In the presence of smooth pursuit eye movements, the contrast sensitivity for increasing target velocities shifts toward lower spatial frequencies. The sensitivity for low spatial frequencies during motion is higher than for a stationary case. This dissertation will propose a method to improve the perceptual quality of video using temporal enhancement prefiltering technique based on the characteristics of Smooth Pursuit Eye Movements (SPEM). The resulting technique closely matches the characteristics of the human visual system (HVS). When motion occurs, the eye tracks the moving targets in a scene as opposed to fixating on any portion of the scene. Hence, psychophysical studies of smooth pursuit eye movements were used as a basis to design the temporal filters. Results of experiments show that temporal enhancement results in improved quality by increasing the apparent sharpness of the image sequence. In this dissertation, a study of research describing how motion affects the image quality at the camera lens and the human eye is presented. This dissertation uses that research to develop a temporal enhancement technique to improve the quality of video degraded by motion.
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Date Issued
2003
PURL
http://purl.flvc.org/fau/fd/FADT12035
Subject Headings
Eye--Movements, Digital video, Visual perception, Video compression
Format
Document (PDF)
fault-tolerant memory architecture for storing one hour of D-1 video in real time on long polyimide tapes
Title
A fault-tolerant memory architecture for storing one hour of D-1 video in real time on long polyimide tapes.
Creator
Monteiro, Pedro Cox de Sousa., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Research is under way to fabricate large-area thin-film transistor arrays produced on a thin polyimide substrate. The polyimide substrate is available in long thirty centimeter wide rolls of tape, and lithography hardware is being developed to expose hundreds of meters of this tape with electrically addressable light modulators which can resolve 2 $\mu$m features. A fault-tolerant memory architecture is proposed that is capable of storing one hour of D-1 component digital video (almost 10^12...
Show moreResearch is under way to fabricate large-area thin-film transistor arrays produced on a thin polyimide substrate. The polyimide substrate is available in long thirty centimeter wide rolls of tape, and lithography hardware is being developed to expose hundreds of meters of this tape with electrically addressable light modulators which can resolve 2 $\mu$m features. A fault-tolerant memory architecture is proposed that is capable of storing one hour of D-1 component digital video (almost 10^12 bits) in real-time, on eight two-hundred meter long tapes. Appropriate error correcting codes and error concealment are proposed to compensate for drop-outs resulting from manufacturing defects so as to yield video images with error rates low enough to survive several generations of copies.
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Date Issued
1992
PURL
http://purl.flvc.org/fcla/dt/14869
Subject Headings
Polyimides, Computer architecture, Memory hierarchy (Computer science), Fault-tolerant computing
Format
Document (PDF)
HVS-based wavelet color image coding
Title
HVS-based wavelet color image coding.
Creator
Guo, Linfeng., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This work is an attempt of incorporating the latest advances in vision research and signal processing into the field of image coding. The scope of the dissertation is twofold. Firstly, it sets up a framework of the wavelet color image coder and makes optimizations of its performance. Secondly, it investigates the human vision models and implements human visual properties into the wavelet color image coder. A wavelet image coding framework consisting of image decomposition, coefficients...
Show moreThis work is an attempt of incorporating the latest advances in vision research and signal processing into the field of image coding. The scope of the dissertation is twofold. Firstly, it sets up a framework of the wavelet color image coder and makes optimizations of its performance. Secondly, it investigates the human vision models and implements human visual properties into the wavelet color image coder. A wavelet image coding framework consisting of image decomposition, coefficients quantization, data representation, and entropy coding is first set up, and then a couple of unsolved issues of wavelet image coding are studied and the consequent optimization schemes are presented and applied to the basic framework. These issues include the best wavelet bases selection, quantizer optimization, adaptive probability estimation in arithmetic coding, and the explicit transmission of significant map of wavelet data. Based on the established wavelet image coding framework, a human visual system (HVS) based adaptive color image coding scheme is proposed. Compared with the non-HVS-based coding methods, our method results in a superior performance without any cost of additional side information. As the rudiments of the proposed HVS-based coding scheme, the visual properties of the early stage of human vision are investigated first, especially the contrast sensitivity, the luminance adaptation, and the complicated simultaneous masking and crossed masking effects. To implement these visual properties into the wavelet image coding, the suitable estimation of local background luminance and contrast in the wavelet domain is also re-investigated. Based upon these prerequisite works, the effects of contrast sensitivity weighting and luminance adaptation are incorporated into our coding scheme. Furthermore, the mechanisms of all kinds of masking effects in color image, e.g., the self-masking, the neighbor masking, the crossbands masking, and the luminance-chrominance crossed-masking, are also studied and properly utilized into the coding scheme through an adaptive quantization scheme. Owing to elaborate arrangement and integration of the different parts of the perception based quantization scheme, the coefficient-dependent adaptive quantization step size can be losslessly restored during the decoding without any overhead of side information.
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Date Issued
2001
PURL
http://purl.flvc.org/fcla/dt/11941
Subject Headings
Wavelets (Mathematics), Image processing--Digital techniques
Format
Document (PDF)
Measurement of brain activity using an ultrasonic measure of localized blood flow
Title
Measurement of brain activity using an ultrasonic measure of localized blood flow.
Creator
Dinev, Petko Dimitrov., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This dissertation presents a new type of two-dimensional, real time, color ultrasonic scanner able to measure and display brain metabolism by monitoring amplitudes of localized changes of intracranial interfaces. A real time image is obtained with a flexible array of transducers which eliminates the strong reflection from the skull due to a shape mismatch, and reduces the topological mislocations in the image. The image is generated by a superposition of a gray scale image representing static...
Show moreThis dissertation presents a new type of two-dimensional, real time, color ultrasonic scanner able to measure and display brain metabolism by monitoring amplitudes of localized changes of intracranial interfaces. A real time image is obtained with a flexible array of transducers which eliminates the strong reflection from the skull due to a shape mismatch, and reduces the topological mislocations in the image. The image is generated by a superposition of a gray scale image representing static structures, and a color coded pattern representing motion information. The new technique of motion detection based on image subtraction features high accuracy and gives the scanner the unique capability to detect multidirectional motion of the intracranial interfaces, and to display the amplitude of the motion in real time. A series of experiments performed with the scanner demonstrates outstanding agreement between theoretical design and hardware performance. The scanner has been measured to have a lateral resolution of 4 mm, a temporal resolution of 30 fr/s, a motion detection resolution of 5 $\mu$m, a time gain compensation of 40 dB, and a signal/noise ratio of more than 40 dB. Successful tests, performed on a live human brain, show a well defined echo pattern arising from intracranial structures within the brain, and a strong correlation between the detected surface pulsations and heart beat has been observed. Monitoring the image synchronously with the heart beat and the external stimulus presence gives clinicians the unique opportunity of visualization of detailed cross-sectional anatomy of portions of the human brain, permitting direct observation, mapping the structure and function in a normal human brain, and studying the pathophysiology of mental illness by demonstrating structural metabolic, and neurochemical abnormalities. Additional experiments, performed on other parts of the human body, demonstrated clearly the advanced features of the scanner and its successful application to other areas of medicine beyond neurology. Furthermore, this new real time, two-dimensional brain scanner will be suitable for remote diagnosis and consultation, and long-distance delivery of quality health care via teleconferencing and telecommunication equipment. The modular design of the scanner allows blocks, such as multidirectional motion detection, and the flexible transducer array to be used as stand alone units or to be built into already existing ultrasonic equipment such as sonars, motion sensors, nondestructive testing of materials, etc.
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Date Issued
1996
PURL
http://purl.flvc.org/fcla/dt/12485
Subject Headings
Diagnosis, Ultrasonic, Blood-vessels--Ultrasonic imaging, Ultrasonics in medicine
Format
Document (PDF)
Performance modeling of liquid crystal phase diffraction gratings suitable for HDTV projection systems
Title
Performance modeling of liquid crystal phase diffraction gratings suitable for HDTV projection systems.
Creator
Wu, Kaiyu., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Because of the inherent inefficiency associated with polarization-rotation liquid crystal light valves in an high intensity environment, this paper discusses the applicability and performance of these valves operated as phase diffraction gratings in HDTV projection systems. A numerical method for evaluating performance and optimizing design parameters is presented. The resulting model is used to consider design improvement to increase the modulation efficiency and to adapt the projector to...
Show moreBecause of the inherent inefficiency associated with polarization-rotation liquid crystal light valves in an high intensity environment, this paper discusses the applicability and performance of these valves operated as phase diffraction gratings in HDTV projection systems. A numerical method for evaluating performance and optimizing design parameters is presented. The resulting model is used to consider design improvement to increase the modulation efficiency and to adapt the projector to use unpolarized light as well as linearly polarized light. The modeling results are used to determine and optimize the parameters of the liquid crystal panel, such as, the refractive index of the liquid crystal, the thickness of liquid crystal cells, and the width of panel pixels.
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Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/15121
Subject Headings
High definition television, Liquid crystals, Liquid crystal devices
Format
Document (PDF)