81 
Sliding Mode Observer Design for Permanent Magnetic Synchronous Generator Based Wind Energy Conversion SystemsHuang, Yuansheng 18 May 2017 (has links)
<p> Realtime rotor position and speed information is essential for effective power control of permanent magnet synchronous generatorbased wind energy conversion systems. The presence of traditional encoders can increase the size, cost and complexity, but also reduce the overall system lifetime and reliability. To provide a more reliable sensorless wind generation control scheme and eliminate the reliance on encoders, this paper presents a novel high order sliding mode observer for power control of permanent magnet synchronous generatorbased wind energy conversion systems. Compared with the first order sliding mode observer, a high order sliding mode observer shows superior estimation accuracy with significantly reduced chattering effect. A threelevel neutralpointclamped space vector pulse width modulation (NPCSVPWM) based power converter is used to reduce the voltage stress on power switching devices and produce less harmonics in the output waveforms compared with a traditional twolevel inverter. Computer simulation results have shown the superior performance of the purposed high order sliding mode observer in wind turbine power control applications.</p>

82 
PlaneWave Scattering of a Periodic Corrugated CylinderGarcia, Samuel 07 June 2017 (has links)
<p> In this dissertation, a novel approach to modeling the scattered field of a periodic corrugated cylinder, from an oblique incident planewave, is presented. The approach utilizes radial waveguide approximations for fields within the corrugations, which are point matched to approximated scattered fields outside of the corrugation to solve for the expansion coefficients. The point matching is done with TMz and TEz modes simultaneously, allowing for hybrid modes to exist.</p><p> The derivation of the fields and boundary conditions used are discussed in detail. Axial and radial propagating modes for the scattered fields are derived and discussed. Close treatment is given to field equations summation truncation and conversion to matrix form, for numerical computing. A detailed account of the modeling approach using Mathematica® and NCAlgebra for the noncommutative algebra, involved in solving for the expansion coefficients, are also given.</p><p> The modeling techniques offered provide a full description and prediction of the scattered field of a periodic corrugated cylinder. The model is configured to approximate a smooth cylinder, which is then compared against that of a textbook standard smooth cylinder. The methodology and analysis applied in this research provide a solution for computational electromagnetics, RF communications, Radar systems and the like, for the design, development, and analysis of such systems. Through the rapid modeling techniques developed in this research, early knowledge discovery can be made allowing for better more effective decision making to be made early in the design and investigation process of an RF project. </p>

83 
A Radio Frequency Identification MultiSensor Health Monitoring SystemSakki, Kranthi Kumar 28 April 2017 (has links)
<p> Health Monitoring Systems (HMS) are used to monitor physiological signals such as the blood pressure, heart rate, and temperature of patients. The use of a HMS for continuous monitoring of the Vital Signs of patients requiring constant medical supervision, is particularly important. The current project presents the development and implementation of a multisensor HMS to track and record multiple parameters of a patient (Electrocardiogram, pulse, temperature, and body position). The project development uses biomedical sensor technology for monitoring the physiological signals, Radio Frequency Identification (RFID) technology for patient identification, and the Internet of Things (IoT) for information transmission. Sensors attached to a patient’s body collect data that alert users to abnormal values via smart devices, such as mobile phones or laptops. Experimental testing of the multisensor HMS developed and implemented for this project, demonstrates the system’s effectiveness in sensing, collecting, and transmitting accurate patient information for remote monitoring.</p>

84 
Single event transient and total ionizing dose effects on IIIV MOSFETs for sub10 nm node CMOSNi, Kai 16 September 2016 (has links)
With CMOS scaling continuing to sub10 nm node, Si is approaching its physical limits. To enable further scaling, alternative channel materials with superior transport properties are proposed to replace Si in the channel. IIIV/Ge emerge as promising channel materials for NMOS/PMOS, respectively. The lowpower and highspeed nature of these devices represents a strong incentive for their applications in space. However, to apply them in harsh radiation space environment, their radiation responses have to be investigated. In this dissertation, singleeventtransient and totalionizingdose effects are investigated in IIIV MOSFETs with different architectures.
Heavyion irradiations, pulsedlaser irradiations, and TCAD simulations are performed to understand their radiation response. Similar to IIIV FETs with noninsulating gate, IIIV MOSFETs show excess vulnerability to singleeventeffects (SEE) compared with their silicon counterparts. Aside from the charge deposited in the sensitive region by the radiation, IIIV MOSFETs collect additional charge contributed by an activated parasitic bipolar transistor. Although the activation process varies in detail among different architectures, the key process is the same. Slow holes pile up around the source and channel and reduce the sourcetochannel barrier, which causes electrons injecting from the source and collected by the drain. Bipolar amplification factor around 510 is measured, posing serious concerns over their space applications.
Unlike the almost perfect Si/SiO2 interface, oxides on IIIV materials are usually defective and when electrically stressed, charge trapping will happen. Therefore, combined electrical stress and biased Xray irradiation measurements are performed. It shows that electrical stressinduced electron trapping compensates radiationinduced hole trapping during positive gatebias irradiation. Stressinduced hole trapping adds to the effects of radiationinduced hole trapping under negative gate bias. These device level works provide early insights into the radiation effects on IIIV MOSFETs and further circuit level analysis.

85 
Performance of SpaceTime Block Code in MISOOFDM systemWang, Ruoyu 23 December 2016 (has links)
<p> SpaceTime Code (STC) has caused wide public concern in the field of wireless communications over the recent years. Due to interference or signal attenuation, it may cause errors or data loss when the data stream is transmitted through a wireless channel. The SpaceTime Block Code (STBC), which combines the technique of channel coding and antenna diversity, is an effective approach of increasing the capacity of a wireless channel by increasing both the coding gain and diversity gain. Using STBC in Orthogonal FrequencyDivision Multiplexing (OFDM), multiple antennas transmit multiple copies of the data stream, and the receiver can integrate these copies for optimal data. In this system, the wireless signal is more reliable and able to meet more remote wireless transmissions. In this project, three STBCs are applied in 2x1, 3x1, and 4x1 OFDM system respectively, to provide different data rates and reliability. </p>

86 
Misadjustment of 2, 4, and 6 tap linear Adaptive Predictors, and behavioral simulation of 6Tap Prediction Gain on Xilinx VivadoSampathkumar, Shruthi 04 January 2017 (has links)
<p> The objective of this thesis is to compute the Misadjustment of Adaptive Predictors and to implement their fixedpoint design on Xilinx Vivado for a behavioral simulation of the Prediction Gain. In the first part of this thesis, the Misadjustment is mathematically calculated for Adaptive Predictors of different tapweights. These Adaptive Predictors include Least Mean Square (LMS), ForwardBackward LMS (FBLMS), Cascaded LMS (CLMS), and Cascaded ForwardBackward LMS (CFBLMS) for 2, 4, and 6 tapweights. In the second part of this thesis, the 6Tap design of all the four predictors is programmed in Verilog Hardware Description Language (HDL) using MATLAB’s HDL Coder tool and run on the Xilinx Vivado platform for comparing behavioral simulations of the Prediction Gain with that obtained on MATLAB. An alternative method for the Prediction Gain comparison is accomplished by instantiating Xilinx AnalogtoDigital Converter (XADC) block available on 7series FieldProgrammable Gate Array (FPGA) boards as a means to introduce the input signals as voltage values. </p><p> Misadjustment is determined for 2, 4, and 6 tapweights on all four Adaptive Predictors previously mentioned for input signals such as a sinusoid of frequency 0.1Hz contaminated with White Gaussian Noise (WGN), a secondorder AutoRegressive (AR) process, and a speech signal at 8Kbps. The results in every case reveal that FBLMS and CFBLMS show better performance, in terms of Misadjustment, when compared to LMS and CLMS Adaptive Predictors, respectively. Also, irrespective of the input signals, only the 2Tap cascaded Adaptive Predictors such as CFBLMS and CLMS exhibit lower Misadjustment than the 2Tap noncascaded FBLMS and LMS predictors. And, in the case of the secondorder AR process input, if AR parameters are chosen so that the eigenvalue spread is sufficiently large, then the performance of 2Tap, 4Tap, and 6Tap CFBLMS and CFLMS predictors have a lower Misadjustment than that of FBLMS and LMS predictors. </p><p> The Prediction Gain calculations for the speech signal input on all the four predictors reveal that the 6Tap CFBLMS and CLMS Adaptive Predictors show much higher gains compared to 6Tap FBLMS and LMS Adaptive Predictors. All four 6Tap predictors, after quantization of tapweights to reduced number of bits for a fixedpoint design, are HDL programmed on Xilinx Vivado. The behavioral simulation for Prediction Gain obtained using both the methods described reveal that the result is nearly the same as the Prediction Gain value obtained using a MATLAB simulation thereby validating the fitness of the design for FPGA implementation. Also, instantiating the XADC block for introducing input voltages, rather than hardcoding input voltages as binarycodeddecimals into Testbench, gives the leeway to feed different sets of input signals directly as voltage parameters.</p>

87 
An assistive navigational device for the blind and the visually impairedTimiri Vijayakumar, Siddharth 04 January 2017 (has links)
<p> One of the major challenges faced by the blind and the visually impaired in their daily activities, is independent navigation in an urban setting. There may be protrusions, potholes, excavations, vehicles, etc. on their path. The main aim of the assistive devices is to make the visually impaired or the blind more independent and selfsufficient. White canes and guide dogs are the primitive mobility aids they use. Currently there are many Electronic Travel Aids (ETA) and Accessible Pedestrian Signals (APS) available in the market such as the smart canes, radix rotating cone, etc.</p><p> This project presents the development, hardware implementation and testing of an Electronic Travel Aid (ETA) system, which can be used by the blind or the visually impaired for independent navigation within an urban environment. The system uses nRf24L01+ radio modules to communicate information about the street grid to user. The information includes distance to the next intersection, structure of the intersection, intersection name, and pedestrian signal status. The information is received on a handheld device and can be converted to a voice signal by a speech synthesis device.</p>

88 
The Dynamics of Polarized Beliefs in Networks Governed by Viral Diffusion and Media InfluenceSanatkar, Mohammad Reza January 2016 (has links)
<p>The multidimensional joint distributions that represent complex systems with many</p><p>interacting elements can be computationally expensive to characterize. Methods</p><p>to overcome this problem have been introduced by a variety of scientific communities.</p><p>Here, we employ methods from statistics, information theory and statistical</p><p>physics to investigate some approximation techniques for inference over factor graphs</p><p>of spatiallycoupled low density parity check (SCLDPC) codes, estimation of the</p><p>marginals of stationary distribution in influence networks consisting of a number of</p><p>individuals with polarized beliefs, and estimation of pernode marginalized distribution</p><p>for an adoption model of polarized beliefs represented by a Hamiltonian energy</p><p>function.</p><p>The second chapter introduces a new method to compensate for the rate loss of</p><p>SCLDPC codes with small chain lengths. Our interest in this problem is motivated</p><p>by the theoretical question of whether or not the rate loss can be eliminated by</p><p>small modications to the boundary of the protograph? We tackle this question by</p><p>attaching additional variable nodes to the check nodes at the chain boundary. Our</p><p>goal is to increase the code rate while preserving the BP threshold of the original</p><p>chain.</p><p>In the third chapter, we consider the diffusion of polarized beliefs in a social network</p><p>based on the influence of neighbors and the effect of mass media. The adoption</p><p>process is modeled by a stochastic process called the individualbased (INSTOCH)</p><p>system and the effects of viral diffusion and media influence are treated at the individual</p><p>level. The primary difference between our model and other recent studies,</p><p>which model both interpersonal and media influence, is that we consider a third state,</p><p>called the negative state, to represent those individuals who hold positions against</p><p>the innovation in addition to the two standard states neutral (susceptible) and positive</p><p>(adoption). Also, using a meaneld analysis, we approximate the INSTOCH</p><p>system in the large population limit by deterministic differential equations which we</p><p>call the homogeneous meaneld (HOMMEAN) and the heterogeneous meaneld</p><p>(HETMEAN) systems for exponential and scalefree networks, respectively. Based</p><p>on the stability of equilibrium points of these dynamical systems, we derive conditions</p><p>for local and global convergence, of the fraction of negative individuals, to</p><p>zero.</p><p>The fourth chapter also focuses on the diffusion of polarized beliefs but uses a different</p><p>mathematical model for the diffusion of beliefs. In particular, the Potts model</p><p>from statistical physics is used to model the joint distribution of the individual's</p><p>states based on a Hamiltonian energy function. Although the stochastic dynamics</p><p>of this model are not completely dened by the energy function, one can choose any</p><p>Monte Carlo sampling algorithm (e.g., MetropolisHastings) to dene Markovchain</p><p>dynamics. We are primarily interested in the stationary distribution of the Markov</p><p>chain, which is given by the Boltzmann distribution. The fraction of individuals in</p><p>each state at equilibrium can be estimated using both Markovchain Monte Carlo</p><p>methods and the beliefpropagation (BP) algorithm. The main benet of the Potts</p><p>model is that the BP estimates are asymptotically exact in this case.</p> / Dissertation

89 
System Health Awareness in TotalIonizing Dose EnvironmentsDiggins, Zachary John 28 November 2016 (has links)
There is increasing interest in using commercialofftheshelf (COTS) electronics in radiation environments, such as robotic systems for remediation after the nuclear accident at Fukushima or in lowcost CubeSats. Commercial electronics have varying levels or robustness to radiation environments, and without extensive testing and redesign, the survivability of COTS systems in radiation environments is unknown and potentially insufficient. This work identifies characteristics of robotic commercialofftheshelf component degradation, primarily partto part variability and the interactions between the degradation of multiple components. Insight into the health of a class of components, microcontrollers, was developed using timing characteristics. A framework using either continuous or discrete Bayesian networks was developed to model the degradation observed in sensors and other electronic components. The Bayesian network can be incorporated with deterministic models to produce a robust and scalable analysis methodology, granting awareness of how the system will behave in the radiation environment and providing insight into areas for improvement in the system hardware and software.

90 
Optimization of the bowtie gap geometry for a maximum electric field enhancementByambadorj, Tsenguun 30 November 2016 (has links)
<p>Optimization of the geometry of a metallic bowtie gap at radio frequency is
presented in this thesis. Since the design and fabrication of a plasmonic device (nanogap)
at nanoscale is challenging, the results of this study can be used to estimate the best
design parameters for nanogap structure. The geometry of the bowtie gap including gap
size, tip width, metal thickness, and tip angle are investigated at macroscale to find the
maximum electric field enhancement across the gap. This thesis focuses on the
simulation portion of a work that consists of experimental and simulation platforms.
The simulation platform is created by NEC modeling system using antenna
segments. The results indicate that 90? bowtie with 0.06 ? gap size has the most Et2
enhancement. Different amounts of enhancement at different frequency ranges are
explained by mode volume. The product of the mode volume and Et2 enhancement is
constant for different gap structures and different frequencies.

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