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Articles 151 - 180 of 359
Full-Text Articles in Electrical and Electronics
Rain Rate Retrieval Algorithm For Aquarius/Sac-D Microwave Radiometer, Rosa Ana Menzerotolo
Rain Rate Retrieval Algorithm For Aquarius/Sac-D Microwave Radiometer, Rosa Ana Menzerotolo
Electronic Theses and Dissertations
Microwave radiometers are used to measure blackbody microwave emissions emitted by natural targets. Radiative transfer theory provides a well founded physical relationship between the atmosphere and surface geophysical parameters and the brightness temperature measured by these radiometers. The atmospheric brightness temperature is proportional to the integral of the microwave absorption of water vapor, oxygen, and liquid water between the top of the atmosphere and the surface. Inverse radiative transfer models use to retrieve the water vapor, cloud liquid and oxygen content in the atmosphere are very well known; however, the retrieval of rain rate in the atmosphere is still a …
Modeling, Design And Fabrication Of Orthogonal And Psuedo-Orthogonal Frequency Coded Saw Wireless Spread Spectrum Rfid Sensor Tags, Nancy Saldanha
Modeling, Design And Fabrication Of Orthogonal And Psuedo-Orthogonal Frequency Coded Saw Wireless Spread Spectrum Rfid Sensor Tags, Nancy Saldanha
Electronic Theses and Dissertations
Surface acoustic wave (SAW) sensors offer a wireless, passive sensor solution for use in numerous environments where wired sensing can be expensive and infeasible. Single carrier frequency SAW sensor embodiments such as delay lines, and resonators have been used in single sensor environments where sensor identification is not a necessity. The orthogonal frequency coded (OFC) SAW sensor tag embodiment developed at UCF uses a spread spectrum approach that allows interrogation in a multi-sensor environment and provides simultaneous sensing and sensor identi- fication. The SAW device is encoded via proper design of multiple Bragg reflectors at differing frequencies. To enable accurate …
Incremental Lifecycle Validation Of Knowledge-Based Systems Through Commonkads, Feras Batarseh
Incremental Lifecycle Validation Of Knowledge-Based Systems Through Commonkads, Feras Batarseh
Electronic Theses and Dissertations
This dissertation introduces a novel validation method for knowledge-based systems (KBS). Validation is an essential phase in the development lifecycle of knowledge-based systems. Validation ensures that the system is valid, reliable and that it reflects the knowledge of the expert and meets the specifications. Although many validation methods have been introduced for knowledge-based systems, there is still a need for an incremental validation method based on a lifecycle model. Lifecycle models provide a general framework for the developer and a mapping technique from the system into the validation process. They support reusability, modularity and offer guidelines for knowledge engineers to …
Class F And Inverse Class F Power Amplifier Subject To Electrical Stress Effect, Giji Skaria
Class F And Inverse Class F Power Amplifier Subject To Electrical Stress Effect, Giji Skaria
Electronic Theses and Dissertations
This study investigated the Class F and inverse Class F RF power amplifier operating at 5.8 GHz. The major challenging issue in design and implementation of CMOS power transistor is the breakdown voltage especially in sub-micron CMOS technologies. In order to eliminate this problem a Cascode topologies were implemented to reduce the Drain-toSource voltage (stress). A Cascode Class F & Inverse Class F RF power amplifier were designed, and optimized in order to improve efficiency and reliability using 0.18µm CMOS technology process. A 50% decrease in the stress has been achieved in the Cascode class-F and Inverse class F amplifiers. …
Study Of Esd Effects On Rf Power Amplifiers, Raju, Divya Narasimha
Study Of Esd Effects On Rf Power Amplifiers, Raju, Divya Narasimha
Electronic Theses and Dissertations
Today, ESD is a major consideration in the design and manufacture of ICs. ESD problems are increasing in the electronics industry because of the increasing trend toward higher speed and smaller device sizes. There is growing interest in knowing the effects of ESD protection circuit on the performance of semiconductor integrated circuits (ICs) because of the impact it has on core RF circuit performance. This study investigated the impact of ESD protection circuit on RF Power amplifiers. Even though ESD protection for digital circuits has been known for a while, RF-ESD is a challenge. From a thorough literature search on …
Lateral Power Mosfets Hardened Against Single Event Radiation Effects, Patrick Michael Shea
Lateral Power Mosfets Hardened Against Single Event Radiation Effects, Patrick Michael Shea
Electronic Theses and Dissertations
The underlying physical mechanisms of destructive single event effects (SEE) from heavy ion radiation have been widely studied in traditional vertical double-diffused power MOSFETs (VDMOS). Recently lateral double-diffused power MOSFETs (LDMOS), which inherently provide lower gate charge than VDMOS, have become an attractive option for MHz-frequency DC-DC converters in terrestrial power electronics applications [1]. There are growing interests in extending the LDMOS concept into radiation-hard space applications. Since the LDMOS has a device structure considerably different from VDMOS, the well studied single event burn-out (SEB) or single event gate rapture (SEGR) response of VDMOS cannot be simply assumed for LDMOS …
Wirelessly Sensing Resonate Frequency Of Passive Resonators With Different Q Values, Mathew Walter Lukacs
Wirelessly Sensing Resonate Frequency Of Passive Resonators With Different Q Values, Mathew Walter Lukacs
Electronic Theses and Dissertations
Numerous techniques exist for measuring temperature using passive devices such as SAW filters. However, SAW filters have a significant limitation regarding high temperature environments exceeding 1000⁰C [1]. There are several applications for a high temperature sensor in this range, most notably heat flux or temperature in turbine engines. For these environments, an alternative to SAW filters is to use a passive resonator. The resonate frequency will vary depending on the environment temperature. Understanding how the frequency changes with temperature will allow us to determine the environmental temperature. In order for this approach to work, it is necessary to induce resonance …
A Radar Interrogator For Wireless Passive Temperature Sensing, Jeffrey Charles Lambert
A Radar Interrogator For Wireless Passive Temperature Sensing, Jeffrey Charles Lambert
Electronic Theses and Dissertations
In this thesis I explore radio detection and ranging (RADAR) and software defined radio (SDR) in the context of wireless passive sensor interrogation. A RADAR topology is selected based upon preliminary measurements using ordinary laboratory instrumentation and then used for construction of a prototype X-band wireless measurement system using commercial, off-theshelf (COTS) components. This research explores the feasibility of wireless passive sensor interrogation through practical application of SDR and RADAR techniques to the interrogation of a wireless passive resonator signal. This work serves as a foundation for further research on sensor interrogation through establishment of critical system parameters in the …
Investigation Of Reactively Sputtered Boron Carbon Nitride Thin Films, Vinit O. Todi
Investigation Of Reactively Sputtered Boron Carbon Nitride Thin Films, Vinit O. Todi
Electronic Theses and Dissertations
Research efforts have been focused in the development of hard and wear resistant coatings over the last few decades. These protective coatings find applications in the industry such as cutting tools, automobile and machine part etc. Various ceramic thin films like TiN, TiAlN, TiC, SiC and diamond-like carbon (DLC) are examples of the films used in above applications. However, increasing technological and industrial demands request thin films with more complicated and advanced properties. For this purpose, B-C-N ternary system which is based on carbon, boron and nitrogen which exhibit exceptional properties and attract much attention from mechanical, optical and electronic …
Exploiting Opponent Modeling For Learning In Multi-Agent Adversarial Games, Kennard R. Laviers
Exploiting Opponent Modeling For Learning In Multi-Agent Adversarial Games, Kennard R. Laviers
Electronic Theses and Dissertations
An issue with learning effective policies in multi-agent adversarial games is that the size of the search space can be prohibitively large when the actions of both teammates and opponents are considered simultaneously. Opponent modeling, predicting an opponent’s actions in advance of execution, is one approach for selecting actions in adversarial settings, but it is often performed in an ad hoc way. In this dissertation, we introduce several methods for using opponent modeling, in the form of predictions about the players’ physical movements, to learn team policies. To explore the problem of decision-making in multi-agent adversarial scenarios, we use our …
Multiagent Learning Through Indirect Encoding, David B. D'Ambrosio
Multiagent Learning Through Indirect Encoding, David B. D'Ambrosio
Electronic Theses and Dissertations
Designing a system of multiple, heterogeneous agents that cooperate to achieve a common goal is a difficult task, but it is also a common real-world problem. Multiagent learning addresses this problem by training the team to cooperate through a learning algorithm. However, most traditional approaches treat multiagent learning as a combination of multiple single-agent learning problems. This perspective leads to many inefficiencies in learning such as the problem of reinvention, whereby fundamental skills and policies that all agents should possess must be rediscovered independently for each team member. For example, in soccer, all the players know how to pass and …
Live Video Database Management Systems, Rui Peng
Live Video Database Management Systems, Rui Peng
Electronic Theses and Dissertations
With the proliferation of inexpensive cameras and the availability of high-speed wired and wireless networks, networks of distributed cameras are becoming an enabling technology for a broad range of interdisciplinary applications in domains such as public safety and security, manufacturing, transportation, and healthcare. Today’s live video processing systems on networks of distributed cameras, however, are designed for specific classes of applications. To provide a generic query processing platform for applications of distributed camera networks, we designed and implemented a new class of general purpose database management systems, the live video database management system (LVDBMS). We view networked video cameras as …
Architectural Support For Improving System Hardware/Software Reliability, Martin Dimitrov
Architectural Support For Improving System Hardware/Software Reliability, Martin Dimitrov
Electronic Theses and Dissertations
It is a great challenge to build reliable computer systems with unreliable hardware and buggy software. On one hand, software bugs account for as much as 40% of system failures and incur high cost, an estimate of $59.5B a year, on the US economy. On the other hand, under the current trends of technology scaling, transient faults (also known as soft errors) in the underlying hardware are predicted to grow at least in proportion to the number of devices being integrated, which further exacerbates the problem of system reliability. We propose several methods to improve system reliability both in terms …
Bit-Rate Aware Reconfigurable Architecture For H.264/Avc Deblocking Filter, Rakan Khraisha
Bit-Rate Aware Reconfigurable Architecture For H.264/Avc Deblocking Filter, Rakan Khraisha
Electronic Theses and Dissertations
In H.264/AVC, DeBlocking Filter (DBF) achieves bit rate savings and it is used to improve visual quality by reducing the presence of blocking artifacts. However, these advantages come at the expense of increasing computational complexity of the DBF due to highly adaptive mode decision and small 4x4 block size. The DBF easily accounts for one third of the computational complexity of the decoder. The computational complexity required for various target applications from mobile to high definition video applications varies significantly. Therefore, it becomes apparent to design efficient architecture to adapt to different requirements. In this work, we exploit the scalability …
The Relevance Of Time-To-Digital Converters To Small Platform Direction Finding Systems, Paul Jeffrey Nelson
The Relevance Of Time-To-Digital Converters To Small Platform Direction Finding Systems, Paul Jeffrey Nelson
Electronic Theses and Dissertations
This thesis explores a Time-Difference-of-Arrival (TDOA) approach to radio direction finding, utilizing picosecond-resolution Time-to-Digital Converters (TDCs). By measuring the relative time of arrival of a pulsed RF signal impinging on an antenna array, direction of arrival (DOA) can be ascertained. This technology enables versatile DOA calculation on platforms only several meters in length, and offers various size, weight, power, and cost advantages when compared to present DF technologies. A short baseline S-band TDOA DF system utilizing TDCs is designed, fabricated, and tested in a laboratory environment. This research suggests that such a DF system based on TDCs provides sufficient accuracy …
Modeling And Design Of Multi-Port Dc/Dc Converters, Zhijun Qian
Modeling And Design Of Multi-Port Dc/Dc Converters, Zhijun Qian
Electronic Theses and Dissertations
In this dissertation, a new satellite platform power architecture based on paralleled three-port DC/DC converters is proposed to reduce the total satellite power system mass. Moreover, a fourport DC/DC converter is proposed for renewable energy applications where several renewable sources are employed. Compared to the traditional two-port converter, three-port or four-port converters are classified as multi-port converters. Multi-port converters have less component count and less conversion stage than the traditional power processing solution which adopts several independent two-port converters. Due to their advantages multi-port converters recently have attracted much attention in academia, resulting in many topologies for various applications. But …
High-Density And High-Efficiency Soft Switching Modular Bi-Directional Dc-Dc Converter For Hybrid Electric Vehicles, John Elmes
Electronic Theses and Dissertations
This dissertation1 presents the design of a high-density and high-efficiency soft-switching bi-directional DC-DC converter for hybrid-electric vehicles. The converter operates in a new bidirectional interleaved variable-frequency quasi-square-wave (QSW) mode, which enables high efficiency, high switching frequency, and high power-density. The converter presented utilizes a new variable frequency interleaving approach which allows for each module to operate in an interleaved position while allowing for tolerance in inductance and snubber capacitor values. The variable frequency interleaved soft-switching operation paired with a high-density nanocrystalline inductor and high-density system structure results in a very high performance converter, well exceeding that of the current technology. …
Robust Dialog Management Through A Context-Centric Architecture, Victor C. Hung
Robust Dialog Management Through A Context-Centric Architecture, Victor C. Hung
Electronic Theses and Dissertations
This dissertation presents and evaluates a method of managing spoken dialog interactions with a robust attention to fulfilling the human user’s goals in the presence of speech recognition limitations. Assistive speech-based embodied conversation agents are computer-based entities that interact with humans to help accomplish a certain task or communicate information via spoken input and output. A challenging aspect of this task involves open dialog, where the user is free to converse in an unstructured manner. With this style of input, the machine’s ability to communicate may be hindered by poor reception of utterances, caused by a user’s inadequate command of …
Query Processing In Location-Based Services, Fuyu Liu
Query Processing In Location-Based Services, Fuyu Liu
Electronic Theses and Dissertations
With the advances in wireless communication technology and advanced positioning systems, a variety of Location-Based Services (LBS) become available to the public. Mobile users can issue location-based queries to probe their surrounding environments. One important type of query in LBS is moving monitoring queries over mobile objects. Due to the high frequency in location updates and the expensive cost of continuous query processing, server computation capacity and wireless communication bandwidth are the two limiting factors for large-scale deployment of moving object database systems. To address both of the scalability factors, distributed computing has been considered. These schemes enable moving objects …
Extreme Ultraviolet Spectral Streak Camera, John Michael Szilagyi
Extreme Ultraviolet Spectral Streak Camera, John Michael Szilagyi
Electronic Theses and Dissertations
The recent development of extreme ultraviolet (EUV) sources has increased the need for diagnostic tools, and has opened up a previously limited portion of the spectrum. With ultrafast laser systems and spectroscopy moving into shorter timescales and wavelengths, the need for nanosecond scale imaging of EUV is increasing. EUV’s high absorption has limited the number of imaging options due to the many atomic resonances in this spectrum. Currently EUV is imaged with photodiodes and X-ray CCDs. However photodiodes are limited in that they can only resolve intensity with respect to time and X-ray CCDs are limited to temporal resolution in …
Design Of A Wideband Dual-Polarized Cavity Backed Slot Antenna, Rajesh Paryani
Design Of A Wideband Dual-Polarized Cavity Backed Slot Antenna, Rajesh Paryani
Electronic Theses and Dissertations
A new technique for designing wideband dual-polarized cavity-backed slot antennas is presented. The structure is in the form of a double-resonant, dual-polarized slot antenna backed by a shallow substrate integrated cavity with a depth of approximately one tenth the free space wavelength. The presence of the cavity behind the slot enhances the antenna's directivity and reduces the possibility of surface wave propagation in the antenna substrate when the element is used in an array environment. Moreover, the dual-polarized nature of this radiating element may be exploited to synthesize any desired polarization (vertical, horizontal, RHCP, or LHCP). The double-resonant behavior observed …
The Pdf Of Irradiance For A Free-Space Optical Communications Channel: A Physics Based Model, David Wayne
The Pdf Of Irradiance For A Free-Space Optical Communications Channel: A Physics Based Model, David Wayne
Electronic Theses and Dissertations
An accurate PDF of irradiance for a FSO channel is important when designing a laser radar, active laser imaging, or a communications system to operate over the channel. Parameters such as detector threshold level, probability of detection, mean fade time, number of fades, BER, and SNR are derived from the PDF and determine the design constraints of the receiver, transmitter, and corresponding electronics. Current PDF models of irradiance, such as the Gamma-Gamma, do not fully capture the effect of aperture averaging; a reduction in scintillation as the diameter of the collecting optic is increased. The Gamma-Gamma PDF of irradiance is …
Hurricane Wind Speed And Rain Rate Measurements Using The Airborne Hurricane Imaging Radiometer (Hirad), Ruba Amarin
Hurricane Wind Speed And Rain Rate Measurements Using The Airborne Hurricane Imaging Radiometer (Hirad), Ruba Amarin
Electronic Theses and Dissertations
This dissertation presents results for an end-to-end computer simulation of a new airborne microwave remote sensor, the Hurricane Imaging Radiometer, HIRAD, which will provide improved hurricane surveillance. The emphasis of this research is the retrieval of hurricane-force wind speeds in the presence of intense rain and over long atmospheric slant path lengths that are encountered across its wide swath. Brightness temperature (Tb) simulations are performed using a forward microwave radiative transfer model (RTM) that includes an ocean surface emissivity model at high wind speeds developed especially for HIRAD high incidence angle measurements and a rain model for the hurricane environment. …
Conventional And Zvt Synchronous Buck Converter Design, Analysis, And Measurement, Mark Cory
Conventional And Zvt Synchronous Buck Converter Design, Analysis, And Measurement, Mark Cory
Electronic Theses and Dissertations
The role played by power converting circuits is extremely important to almost any electronic system built today. Circuits that use converters of any type depend on power that is consistent in form and reliable in order to properly function. In addition, today's demands require more efficient use of energy, from large stationary systems such as power plants all the way down to small mobile devices such as laptops and cell phones. This places a need to reduce any losses to a minimum. The power conversion circuitry in a system is a very good place to reduce a large amount of …
Characterization Of Aluminum Doped Zinc Oxide Thin Films For Photovoltaic Applications, Bojanna P. Shantheyanda
Characterization Of Aluminum Doped Zinc Oxide Thin Films For Photovoltaic Applications, Bojanna P. Shantheyanda
Electronic Theses and Dissertations
Growing demand for clean source of energy in the recent years has increased the manufacture of solar cells for converting sun energy directly into electricity. Research has been carried out around the world to make a cheaper and more efficient solar cell technology by employing new architectural designs and developing new materials to serve as light absorbers and charge carriers. Aluminum doped Zinc Oxide thin film, a Transparent conductive Oxides (TCO) is used as a window material in the solar cell these days. Its increased stability in the reduced ambient, less expensive and more abundance make it popular among the …
Design Of Silicon Controlled Rectifers Sic] For Robust Electrostatic Discharge Protection Applications, Zhiwei Liu
Design Of Silicon Controlled Rectifers Sic] For Robust Electrostatic Discharge Protection Applications, Zhiwei Liu
Electronic Theses and Dissertations
Electrostatic Discharge (ESD) phenomenon happens everywhere in our daily life. And it can occurs through the whole lifespan of an Integrated Circuit (IC), from the early wafer fabrication process, extending to assembly operation, and finally ending at the user‟s site. It has been reported that up to 35% of total IC field failures are ESD-induced, with estimated annual costs to the IC industry running to several billion dollars. The most straightforward way to avoid the ICs suffering from the threatening of ESD damages is to develop on-chip ESD protection circuits which can afford a robust, low-impedance bypassing path to divert …
Phoneme-Based Video Indexing Using Phonetic Disparity Search, Carlos Leon Barth
Phoneme-Based Video Indexing Using Phonetic Disparity Search, Carlos Leon Barth
Electronic Theses and Dissertations
This dissertation presents and evaluates a method to the video indexing problem by investigating a categorization method that transcribes audio content through Automatic Speech Recognition (ASR) combined with Dynamic Contextualization (DC), Phonetic Disparity Search (PDS) and Metaphone indexation. The suggested approach applies genome pattern matching algorithms with computational summarization to build a database infrastructure that provides an indexed summary of the original audio content. PDS complements the contextual phoneme indexing approach by optimizing topic seek performance and accuracy in large video content structures. A prototype was established to translate news broadcast video into text and phonemes automatically by using ASR …
Modeling And Simulation Of Soft Bodies, Jaruwan Mesit
Modeling And Simulation Of Soft Bodies, Jaruwan Mesit
Electronic Theses and Dissertations
As graphics and simulations become more realistic, techniques for approximating soft body objects, that is, non-solid objects such as liquids, gases, and cloth, are becoming increasingly common. The proposed generalized soft body method encompasses some specific cases of other existing models enabling simulation of a variety of soft body materials by parameter adjustment. This research presents a general method of soft body model and simulation in which parameters for body control, surface deformation, volume control, and gravitation, can be adjusted to simulate different types of soft bodies. In this method, the soft body mesh structure maintains configuration among surface points …
The Next Generation Botnet Attacks And Defenses, Ping Wang
The Next Generation Botnet Attacks And Defenses, Ping Wang
Electronic Theses and Dissertations
A "botnet" is a network of compromised computers (bots) that are controlled by an attacker (botmasters). Botnets are one of the most serious threats to today’s Internet; they are the root cause of many current Internet attacks, such as email spam, distributed denial of service (DDoS) attacks , click fraud, etc. There have been many researches on how to detect, monitor, and defend against botnets that have appeared and their attack techniques. However, it is equally important for us to investigate possible attack techniques that could be used by the next generation botnets, and develop effective defense techniques accordingly in …
Reactive Control Of Autonomous Dynamical Systems, Jiangmin Chunyu
Reactive Control Of Autonomous Dynamical Systems, Jiangmin Chunyu
Electronic Theses and Dissertations
This thesis mainly consists of five independent papers concerning the reactive control design of autonomous mobile robots in the context of target tracking and cooperative formation keeping with obstacle avoidance in the static/dynamic environment. Technical contents of this thesis are divided into three parts. The first part consists of the first two papers, which consider the target-tracking and obstacle avoidance in the static environment. Especially, in the static environment, a fundamental issue of reactive control design is the local minima problem(LMP) inherent in the potential field methods(PFMs). Through introducing a state-dependent planned goal, the first paper proposes a switching control …