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Articles 151 - 180 of 400
Full-Text Articles in Electrical and Electronics
A Microwave Radiometer Roughness Correction Algorithm For Sea Surface Salinity Retrieval, Yazan Henry Hejazin
A Microwave Radiometer Roughness Correction Algorithm For Sea Surface Salinity Retrieval, Yazan Henry Hejazin
Electronic Theses and Dissertations
The Aquarius/SAC-D is an Earth Science remote sensing satellite mission to measure global Sea Surface Salinity (SSS) that is sponsored by the NASA and the Argentine Space Agency (CONAE). The prime remote sensor is the Aquarius (AQ) L-band radiometer/scatterometer, which measures the L-band emitted blackbody radiation (brightness temperature) from the ocean. The brightness temperature at L-band is proportional to the ocean salinity as well as a number of physical parameters including ocean surface wind speed. The salinity retrieval algorithm make corrections for all other parameters before retrieving salinity, and the greatest of these is the increased brightness temperature due to …
Complex-Valued Adaptive Digital Signal Enhancement For Applications In Wireless Communication Systems, Ying Liu
Electronic Theses and Dissertations
In recent decades, the wireless communication industry has attracted a great deal of research efforts to satisfy rigorous performance requirements and preserve high spectral efficiency. Along with this trend, I/Q modulation is frequently applied in modern wireless communications to develop high performance and high data rate systems. This has necessitated the need for applying efficient complex-valued signal processing techniques to highly-integrated, multi-standard receiver devices. In this dissertation, novel techniques for complex-valued digital signal enhancement are presented and analyzed for various applications in wireless communications. The first technique is a unified block processing approach to generate the complex-valued conjugate gradient Least …
Study Of Design For Reliability Of Rf And Analog Circuits, Hongxia Tang
Study Of Design For Reliability Of Rf And Analog Circuits, Hongxia Tang
Electronic Theses and Dissertations
Due to continued device dimensions scaling, CMOS transistors in the nanometer regime have resulted in major reliability and variability challenges. Reliability issues such as channel hot electron injection, gate dielectric breakdown, and negative bias temperature instability (NBTI) need to be accounted for in the design of robust RF circuits. In addition, process variations in the nanoscale CMOS transistors are another major concern in today‟s circuits design. An adaptive gate-source biasing scheme to improve the RF circuit reliability is presented in this work. The adaptive method automatically adjusts the gate-source voltage to compensate the reduction in drain current subjected to various …
Transient Safe Operating Area (Tsoa) For Esd Applications, Slavica Malobabic
Transient Safe Operating Area (Tsoa) For Esd Applications, Slavica Malobabic
Electronic Theses and Dissertations
A methodology to obtain design guidelines for gate oxide input pin protection and high voltage output pin protection in Electrostatic Discharge (ESD) time frame is developed through measurements and Technology Computer Aided Design (TCAD). A set of parameters based on transient measurements are used to define Transient Safe Operating Area (TSOA). The parameters are then used to assess effectiveness of protection devices for output and input pins. The methodology for input pins includes establishing ESD design targets under Charged Device Model (CDM) type stress in low voltage MOS inputs. The methodology for output pins includes defining ESD design targets under …
Analysis And Design Optimization Of Resonant Dc-Dc Converters, Xiang Fang
Analysis And Design Optimization Of Resonant Dc-Dc Converters, Xiang Fang
Electronic Theses and Dissertations
The development in power conversion technology is in constant demand of high power efficiency and high power density. The DC-DC power conversion is an indispensable stage for numerous power supplies and energy related applications. Particularly, in PV micro-inverters and front-end converter of power supplies, great challenges are imposed on the power performances of the DC-DC converter stage, which not only require high efficiency and density but also the capability to regulate a wide variation range of input voltage and load conditions. The resonant DC-DC converters are good candidates to meet these challenges with the advantages of achieving soft switching and …
Characterization, Morphology, Oxidation, And Recession Of Silicon Nanowires Grown By Electroless Process, Robert G. Mertens
Characterization, Morphology, Oxidation, And Recession Of Silicon Nanowires Grown By Electroless Process, Robert G. Mertens
Electronic Theses and Dissertations
This dissertation presents heretofore undiscovered properties of Silicon Nanowires (SiNWs) grown by electroless process and presents mathematical solutions to the special problems of the oxidation and diffusion of dopants for SiNWs. Also presented here is a mathematical description of morphology of oxidized SiNWs. This dissertation is comprised of several discussions relating to SiNWs growth, oxidation, morphology and doping. In here is presented work derived from a long-term study of SiNWs. Several important aspects of SiNWs were investigated and the results published in journals and conference papers. The recession of SiNWs was heretofore unreported by other research groups. In our investigations, …
Bootstrapping Cognitive Radio Networks, Brent Horine
Bootstrapping Cognitive Radio Networks, Brent Horine
Electronic Theses and Dissertations
Cognitive radio networks promise more efficient spectrum utilization by leveraging degrees of freedom and distributing data collection. The actual realization of these promises is challenged by distributed control, and incomplete, uncertain and possibly conflicting knowledge bases. We consider two problems in bootstrapping, evolving, and managing cognitive radio networks. The first is Link Rendezvous, or how separate radio nodes initially find each other in a spectrum band with many degrees of freedom, and little shared knowledge. The second is how radio nodes can negotiate for spectrum access with incomplete information. To address the first problem, we present our Frequency Parallel Blind …
A New Quasi Resonant Dc-Link For Photovoltaic Micro-Inverters, Anna Grishina
A New Quasi Resonant Dc-Link For Photovoltaic Micro-Inverters, Anna Grishina
Electronic Theses and Dissertations
PV Inverters have the task of tracking the maximum power point (MPP), and regulating the solar energy generation to this optimal operation point. The second task is the conversion of direct current produced by the solar modules into alternating current compatible with the grid. A new inverter approach such as a single phase micro inverter is emerging aimed to overcome some of the challenges of centralized inverters. As a counterpart to the central inverter, a micro inverter is a small compact module attached directly to each solar panel. To provide for the constantly increasing demand for a small size, light …
Wireless Power Transfer For Space Applications: System Design And Electromagnetic Compatibility Compliance Of Radiated Emissions, Ramos Gabriel Vazquez
Wireless Power Transfer For Space Applications: System Design And Electromagnetic Compatibility Compliance Of Radiated Emissions, Ramos Gabriel Vazquez
Electronic Theses and Dissertations
This dissertation evaluates the possibility of wireless power transfer (WPT) systems for space applications, with an emphasis in launch vehicles (rockets). After performing literature review for WPT systems, it was identified that magnetic resonance provides the more suited set of characteristics for this application. Advanced analysis, simulation and testing were performed to magnetic resonance WPT systems to acquire system performance insight. This was accomplished by evaluating/varying coupling configuration, load effects and magnetic element physical characteristics (i.e. wire material, loop radius, etc.). It was identified by analysis, circuit simulation and testing that the best coupling configuration for this application was series-series …
Forecasting Volcanic Activity Using An Event Tree Analysis System And Logistic Regression, William N. Junek
Forecasting Volcanic Activity Using An Event Tree Analysis System And Logistic Regression, William N. Junek
Electronic Theses and Dissertations
Forecasts of short term volcanic activity are generated using an event tree process that is driven by a set of empirical statistical models derived through logistic regression. Each of the logistic models are constructed from a sparse and geographically diverse dataset that was assembled from a collection of historic volcanic unrest episodes. The dataset consists of monitoring measurements (e.g. seismic), source modeling results, and historic eruption information. Incorporating this data into a single set of models provides a simple mechanism for simultaneously accounting for the geophysical changes occurring within the volcano and the historic behavior of analog volcanoes. A bootstrapping …
Engineering Evaluation Of Multi-Beam Satellite Antenna Boresight Pointing Using Land/Water Crossings, Catherine Susan May
Engineering Evaluation Of Multi-Beam Satellite Antenna Boresight Pointing Using Land/Water Crossings, Catherine Susan May
Electronic Theses and Dissertations
The Microwave Radiometer (MWR) on the Aquarius/SAC-D mission measures microwave radiation from earth and intervening atmosphere in terms of brightness temperature (Tb). It takes measurements in a push-broom fashion at K (23.8GHz) and Ka (36.5 GHz) band frequencies using two separate antenna systems, each producing eight antenna beams. Pre-launch knowledge of the alignment of these beams with respect to the space-craft is used to geolocate the antenna footprints on ground. As a part of MWR’s on-orbit engineering check-out, the verification of MWR’s pointing accuracy is discussed here. The technique used to assess MWR’s pointing involved comparing the radiometer image of …
Variance In Fade-Time Of A Gamma-Gamma Distributed Irradiance Signal, Troy T. Leclerc
Variance In Fade-Time Of A Gamma-Gamma Distributed Irradiance Signal, Troy T. Leclerc
Electronic Theses and Dissertations
Free-space optical communications are predominantly hindered by optical turbulence, an effect caused by temperature and pressure variations within the atmosphere. The result is an optical wave interfering with itself due to multipath propagation via tiny refractive-index fluctuations across the wave-front. Optical communication systems are affected when the channel conditions induce fading in the irradiance signal that is received at the detector. The nature of optical interference imparted by the atmosphere is a random process and therefore the received irradiance signal is often characterized by an appropriate probability density function (PDF). Data collected during past free-space optical experiments in the atmosphere …
Synchronous Communication System For Saw Sensors Interrogation, Maxim Troshin
Synchronous Communication System For Saw Sensors Interrogation, Maxim Troshin
Electronic Theses and Dissertations
During past two decades a variety of SAW based wireless sensors were invented and research is still in progress. As different frequencies, varied bandwidths, coding techniques and constantly changing post processing algorithms are being implemented, there is a constant need for a universal and adjustable synchronous communication system able to interrogate new generations of SAW sensors. This thesis presents the design of a multiple FPGA based communication system with an operational frequency range of 450MHz-2.2GHz capable of producing user programmed modulated signal. The synchronous receiver is designed to have interchangeable chip, replacement of which would allow adjustment of the receiver’s …
X-Ray Radiation Enabled Cancer Detection And Treatment With Nanoparticles, Mainul Hossain
X-Ray Radiation Enabled Cancer Detection And Treatment With Nanoparticles, Mainul Hossain
Electronic Theses and Dissertations
Despite significant improvements in medical sciences over the last decade, cancer still continues to be a major cause of death in humans throughout the world. Parallel to the efforts of understanding the intricacies of cancer biology, researchers are continuously striving to develop effective cancer detection and treatment strategies. Use of nanotechnology in the modern era opens up a wide range of possibilities for diagnostics, therapies and preventive measures for cancer management. Although, existing strategies of cancer detection and treatment, using nanoparticles, have been proven successful in case of cancer imaging and targeted drug deliveries, they are often limited by poor …
Virtualization And Self-Organization For Utility Computing, Mehdi Saleh
Virtualization And Self-Organization For Utility Computing, Mehdi Saleh
Electronic Theses and Dissertations
We present an alternative paradigm for utility computing when the delivery of service is subject to binding contracts; the solution we propose is based on resource virtualization and a selfmanagement scheme. A virtual cloud aggregates set virtual machines to work in concert for the tasks specified by the service agreement. A first step for the establishment of a virtual cloud is to create a scale-free overlay network through a biased random walk; scale-free networks enjoy a set of remarkable properties such as: robustness against random failures, favorable scaling, and resilience to congestion, small diameter, and average path length. Constrains such …
The Performance And Power Impact Of Using Multiple Dram Address Mapping Schemes In Multicore Processors, Rami Jadaa
The Performance And Power Impact Of Using Multiple Dram Address Mapping Schemes In Multicore Processors, Rami Jadaa
Electronic Theses and Dissertations
Lowest-level cache misses are satisfied by the main memory through a specific address mapping scheme that is hard-coded in the memory controller. A dynamic address mapping scheme technique is investigated to provide higher performance and lower power consumption, and a method to throttle memory to meet a specific power budget. Several experiments are conducted on single and multithreaded synthetic memory traces -to study extreme cases- and validate the usability of the proposed dynamic mapping scheme over the fixed one. Results show that applications’ performance varies according to the mapping scheme used, and a dynamic mapping scheme achieves up to 2x …
Design And Simulation Of Cmos Active Mixers, Allen Gibson
Design And Simulation Of Cmos Active Mixers, Allen Gibson
Electronic Theses and Dissertations
This paper introduces a component of the Radio Frequency transceiver called the mixer. The mixer is a critical component in the RF systems, because of its ability for frequency conversion. This passage focuses on the design analysis and simulation of multiple topologies for the active down-conversion mixer. This mixer is characterized by its important design properties which consist of conversion gain, linearity, noise figure, and port isolation. The topologies that are given in this passage range from the most commonly known mixer design, to implemented design techniques that are used to increase the mixers important design properties as the demand …
The Acquisition Of Lexical Knowledge From The Web For Aspects Of Semantic Interpretation, Hansen A. Schwartz
The Acquisition Of Lexical Knowledge From The Web For Aspects Of Semantic Interpretation, Hansen A. Schwartz
Electronic Theses and Dissertations
This work investigates the effective acquisition of lexical knowledge from the Web to perform semantic interpretation. The Web provides an unprecedented amount of natural language from which to gain knowledge useful for semantic interpretation. The knowledge acquired is described as common sense knowledge, information one uses in his or her daily life to understand language and perception. Novel approaches are presented for both the acquisition of this knowledge and use of the knowledge in semantic interpretation algorithms. The goal is to increase accuracy over other automatic semantic interpretation systems, and in turn enable stronger real world applications such as machine …
Lyapunov-Based Control Design For Uncertain Mimo Systems, Zhao Wang
Lyapunov-Based Control Design For Uncertain Mimo Systems, Zhao Wang
Electronic Theses and Dissertations
In this dissertation. we document the progress in the control design for a class of MIMO nonlinear uncertain system from five papers. In the first part, we address the problem of adaptive control design for a class of multi-input multi-output (MIMO) nonlinear systems. A Lypaunov based singularity free control law, which compensates for parametric uncertainty in both the drift vector and the input gain matrix, is proposed under the mild assumption that the signs of the leading minors of the control input gain matrix are known. Lyapunov analysis shows global uniform ultimate boundedness (GUUB) result for the tracking error under …
Integration Of High-Q Filters With Highly Efficient Antennas, Yazid Yusuf
Integration Of High-Q Filters With Highly Efficient Antennas, Yazid Yusuf
Electronic Theses and Dissertations
The integration of high-quality (Q)-factor 3-D filters with highly efficient antennas is addressed in this dissertation. Integration of filters and antennas into inseparable units eliminates the transitions between the otherwise separate structures resulting in more compact and efficient systems. The compact, highly efficient integrated 3-D filter/antenna systems, enabled by the techniques developed herein, allow for the realization of integrated RF front ends with significantly- reduced form factors. Integration of cavity filters with slot antennas in a single planar substrate is first demonstrated. Due to the high Q factor of cavity resonators, the efficiency of the integrated filter/antenna system is found …
Exploring Techniques For Measurement And Improvement Of Data Quality With Application To Determination Of The Last Known Position (Lkp) In Search And Rescue (Sar) Data, Abhijit Wakchaure
Exploring Techniques For Measurement And Improvement Of Data Quality With Application To Determination Of The Last Known Position (Lkp) In Search And Rescue (Sar) Data, Abhijit Wakchaure
Electronic Theses and Dissertations
There is a tremendous volume of data being generated in today’s world. As organizations around the globe realize the increased importance of their data as being a valuable asset in gaining a competitive edge in a fast-paced and a dynamic business world, more and more attention is being paid to the quality of the data. Advances in the fields of data mining, predictive modeling, text mining, web mining, business intelligence, health care analytics, etc. all depend on clean, accurate data. That one cannot effectively mine data, which is dirty, comes as no surprise. This research is an exploratory study of …
Analysis Of Behaviors In Crowd Videos, Ramin Mehran
Analysis Of Behaviors In Crowd Videos, Ramin Mehran
Electronic Theses and Dissertations
In this dissertation, we address the problem of discovery and representation of group activity of humans and objects in a variety of scenarios, commonly encountered in vision applications. The overarching goal is to devise a discriminative representation of human motion in social settings, which captures a wide variety of human activities observable in video sequences. Such motion emerges from the collective behavior of individuals and their interactions and is a significant source of information typically employed for applications such as event detection, behavior recognition, and activity recognition. We present new representations of human group motion for static cameras, and propose …
Spectrum Sharing And Service Pricing In Dynamic Spectrum Access Networks, Swastik Kumar Brahma
Spectrum Sharing And Service Pricing In Dynamic Spectrum Access Networks, Swastik Kumar Brahma
Electronic Theses and Dissertations
Traditionally, radio spectrum has been statically allocated to wireless service providers (WSPs). Regulators, like FCC, give wireless service providers exclusive long term licenses for using specific range of frequencies in particular geographic areas. Moreover, restrictions are imposed on the technologies to be used and the services to be provided. The lack of flexibility in static spectrum allocation constrains the ability to make use of new technologies and the ability to redeploy the spectrum to higher valued uses, thereby resulting in inefficient spectrum utilization [23, 38, 42, 62, 67]. These limitations have motivated a paradigm shift from static spectrum allocation towards …
Global Secure Sets Of Trees And Grid-Like Graphs, Yiu Yu Ho
Global Secure Sets Of Trees And Grid-Like Graphs, Yiu Yu Ho
Electronic Theses and Dissertations
Let G = (V, E) be a graph and let S ⊆ V be a subset of vertices. The set S is a defensive alliance if for all x ∈ S, |N[x] ∩ S| ≥ |N[x] − S|. The concept of defensive alliances was introduced in [KHH04], primarily for the modeling of nations in times of war, where allied nations are in mutual agreement to join forces if any one of them is attacked. For a vertex x in a defensive alliance, the number of neighbors of x inside the alliance, plus the vertex x, is at least the number …
A Contextual Approach To Learning Collaborative Behavior Via Observation, Cynthia L. Johnson
A Contextual Approach To Learning Collaborative Behavior Via Observation, Cynthia L. Johnson
Electronic Theses and Dissertations
This dissertation describes a novel technique to creating a simulated team of agents through observation. Simulated human teamwork can be used for a number of purposes, such as expert examples, automated teammates for training purposes and realistic opponents in games and training simulation. Current teamwork simulations require the team member behaviors be programmed into the simulation, often requiring a great deal of time and effort. None are able to observe a team at work and replicate the teamwork behaviors. Machine learning techniques for learning by observation and learning by demonstration have proven successful at observing behavior of humans or other …
Characteristics Of Different Focusing Antennas In The Near Field Region, Shaya Karimkashi
Characteristics Of Different Focusing Antennas In The Near Field Region, Shaya Karimkashi
Electronic Theses and Dissertations
Focusing antennas are of interest in many application including microwave wireless power transmission, remote (non-contact) sensing, and medical applications. Different kinds of antennas such as array antennas, reflector antennas and Fresnel zone plate (FZP) antennas have been used for these applications. Here, first, a new scheme in designing focused array antennas with desired sidelobe levels (SLLs) in the near field region is presented. The performance of the large focused array antennas is predicted based on the knowledge of the mutual admittances of a smaller array. The effects of various focal distances on the near field pattern of these antennas are …
Cmos Rf Cituits Sic] Variability And Reliability Resilient Design, Modeling, And Simulation, Yidong Liu
Cmos Rf Cituits Sic] Variability And Reliability Resilient Design, Modeling, And Simulation, Yidong Liu
Electronic Theses and Dissertations
The work presents a novel voltage biasing design that helps the CMOS RF circuits resilient to variability and reliability. The biasing scheme provides resilience through the threshold voltage (VT) adjustment, and at the mean time it does not degrade the PA performance. Analytical equations are established for sensitivity of the resilient biasing under various scenarios. Power Amplifier (PA) and Low Noise Amplifier (LNA) are investigated case by case through modeling and experiment. PTM 65nm technology is adopted in modeling the transistors within these RF blocks. A traditional class-AB PA with resilient design is compared the same PA without such design …
Investigation And Trade Study On Hot Carrier Reliability Of The Phemt For Dc And Rf Performance, Jason Steighner
Investigation And Trade Study On Hot Carrier Reliability Of The Phemt For Dc And Rf Performance, Jason Steighner
Electronic Theses and Dissertations
A unified study on the hot carrier reliability of the Pseudomorphic High Electron Mobility Transistor (PHEMT) is carried out through Sentaurus Device Simulation, measurement, and physical analyses. A trade study of devices with four various geometries are evaluated for DC and RF performance. The trade-off of DC I-V characteristics, transconductance, and RF parameters versus hot carrier induced gate current is assessed for each device. Ambient temperature variation is also evaluated to observe its impact on hot carrier effects. A commercial grade PHEMT is then evaluated and measured to demonstrate the performance degradation that occurs after a period of operation in …
Feature Pruning For Action Recognition In Complex Environment, Adarsh Nagaraja
Feature Pruning For Action Recognition In Complex Environment, Adarsh Nagaraja
Electronic Theses and Dissertations
A significant number of action recognition research efforts use spatio-temporal interest point detectors for feature extraction. Although the extracted features provide useful information for recognizing actions, a significant number of them contain irrelevant motion and background clutter. In many cases, the extracted features are included as is in the classification pipeline, and sophisticated noise removal techniques are subsequently used to alleviate their effect on classification. We introduce a new action database, created from the Weizmann database, that reveals a significant weakness in systems based on popular cuboid descriptors. Experiments show that introducing complex backgrounds, stationary or dynamic, into the video …
An Improved Ocean Vector Winds Retrieval Approach Using C- And Ku-Band Scatterometer And Multi-Frequency Microwave Radiometer Measurements, Suleiman Odeh Alsweiss
An Improved Ocean Vector Winds Retrieval Approach Using C- And Ku-Band Scatterometer And Multi-Frequency Microwave Radiometer Measurements, Suleiman Odeh Alsweiss
Electronic Theses and Dissertations
This dissertation will specifically address the issue of improving the quality of satellite scatterometer retrieved ocean surface vector winds (OVW), especially in the presence of strong rain associated with tropical cyclones. A novel active/passive OVW retrieval algorithm is developed that corrects Ku-band scatterometer measurements for rain effects and then uses them to retrieve accurate OVW. The rain correction procedure makes use of independent information available from collocated multi-frequency passive microwave observations provided by a companion sensor and also from simultaneous C-band scatterometer measurements. The synergy of these active and passive measurements enables improved correction for rain effects, which enhances the …