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Electrical and Computer Engineering

2005

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Articles 31 - 60 of 119

Full-Text Articles in Physical Sciences and Mathematics

The Synthesis, Characteristics And Performance Of Cnt Composites As Anodic Materials In Litium-Ion Battery, Quan-Feng Dong, Ming-Sen Zheng, Zhen-Cai Huang, Ming-Gang Jin, Ya-Ding Zhan, Zu-Geng Lin May 2005

The Synthesis, Characteristics And Performance Of Cnt Composites As Anodic Materials In Litium-Ion Battery, Quan-Feng Dong, Ming-Sen Zheng, Zhen-Cai Huang, Ming-Gang Jin, Ya-Ding Zhan, Zu-Geng Lin

Journal of Electrochemistry

As an anodic material for lithium ion battery the carbon nano-tube (CNT) and some compounds based on tin have ever been investigated intensively. The fruited progress has not been made yet, however. In this paper the composites of CNT and Sn/SnO_(2)were synthesized employing two methods and characterized by SEM and XRD. And the electrochemical performance of the composites was investigated.

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A Preliminary Study Of Electrocrystallization Of Bismuth On Glassy Carbon, Min-Li Yang, Zhan-Jun Zhang May 2005

A Preliminary Study Of Electrocrystallization Of Bismuth On Glassy Carbon, Min-Li Yang, Zhan-Jun Zhang

Journal of Electrochemistry

The electrocrystallization of bismuth on glassy carbon electrodes (GCEs) from nitrate solutions was studied by cyclic voltammetry and chronoamperometry. Cyclic voltammograms exhibit a crossover between the cathodic and anodic branches, characteristic of the formation of bismuth nuclei on GCEs, and show that the bismuth electrocrystallization on GCEs is a diffusion-controlled reaction. The current transients were analyzed with the Scharifker and the Heerman equations. With the increaseof Bi~(3+)concentration, the non-dimensional plots leaned to the theoretical curve for 3D instantaneous nucleation and growth. The overpotential dependence of nucleation and growth mechanism was also found. With the increase of overpotential, the non-dimensional curve …

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Preparation And Characterization Of Mcm-41/ Pvdf-Hfp Composite Microporous Polymer Electrolytes For Li-Ion Batteries, Zuo-Feng Chen May 2005

Preparation And Characterization Of Mcm-41/ Pvdf-Hfp Composite Microporous Polymer Electrolytes For Li-Ion Batteries, Zuo-Feng Chen

Journal of Electrochemistry

MCM-41/vinylidine fluoride-hexafluropropene copolymer (PVdF-HFP) composite microporous polymer electrolytes were prepared with mixed solvent of N, N-Dimethylformamide (DMF) and acetone. The influence of MCM-41 and nano-SiO_(2) on the porous structure of the microporous polymer electrolytes were studied with SEM. The results show that MCM-41 could take the place of the plasticizer in the process of making pores, and bring the preparation of microporous membranes easily. The preliminary electrochemical tests showed that the ion conductivity of composite microporous polymer electrolyte with 10% MCM-41 was about 10~(-3) S cm~(-1), and the performance of batteries was improved. The mesoporous MCM-41selected in the paper possesses …

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Application Of Nickel Foam Electrode For Electroreduction Intermediate Of Purine, Hui-Wen Yang, Xi-En Hu, Xue-Jun Wang May 2005

Application Of Nickel Foam Electrode For Electroreduction Intermediate Of Purine, Hui-Wen Yang, Xi-En Hu, Xue-Jun Wang

Journal of Electrochemistry

Nickel foam with weight uniformity, good porosity ,pore size and low resistivity as a three-dimensional cathode was used in a filter-press electrochemical reactor. The H_(2)SO_(4) as supporting electrolyte, separator of cation ion exchange membrane, and the lead plate as an anode were used. The cyclic system consisted of electroreduction reactor, pump, store tank and ampere meter. NAU was electroreduced in the cathode chamber of the reactor. Purine intermediate was synthesized with DAU, and the results were compared with those of iron powder reduction process. A peak current in the electroreduction process was detected. The current density of nickel foam increased …

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Investigation On Ru-Ti-Ir-Sn Oxide Anode Coatings For Electrolyzing Seawater, Wang Ke May 2005

Investigation On Ru-Ti-Ir-Sn Oxide Anode Coatings For Electrolyzing Seawater, Wang Ke

Journal of Electrochemistry

The anode coatings of Ru-Ti-Ir-Sn oxide with various compositions were prepared by thermal decomposition. The physical and electrochemical properties of the coatings were characterized by scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), accelerated life, current efficiency, anti-Mn~(2+)contamination, polarization curveandcyclic voltammetry tests. The results showed thatthe anode coating with optimized formula possessed excellent overall properties for electrolyzing seawater.

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Microwave Reflectometry As A Novel Diagnostic Method For Detection Of Skin Cancers, Kundan Chand, Pratik Mehta, Daryl G. Beetner, R. Zoughi, William V. Stoecker May 2005

Microwave Reflectometry As A Novel Diagnostic Method For Detection Of Skin Cancers, Kundan Chand, Pratik Mehta, Daryl G. Beetner, R. Zoughi, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

More than one million people are diagnosed with skin cancer each year in the United States and more than ten thousand people die from the disease. Currently, there are some methods for early detection of skin cancers, like visual inspection, but improvements are needed. This paper presents a method involving microwave reflectometry as a diagnostic tool for detection of skin cancers. The results of measurements and simulations for normal and wet skin have been shown to distinguish among skin samples with different properties. Microwave measurements from lesions have also been presented which are used to distinguish between cancerous and benign …

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Tb3+-Doped K Pb2Br5: Low-Energy Phonon Mid-Infrared Laser Crystal, U. N. Roy, R. H. Hawrami, Y. Cui, S. Morgan, A. Burger, K. C. Mandal, C. C. Noblitt, S. A. Speakman, K. Rademaker, S. A. Payne Apr 2005

Tb3+-Doped K Pb2Br5: Low-Energy Phonon Mid-Infrared Laser Crystal, U. N. Roy, R. H. Hawrami, Y. Cui, S. Morgan, A. Burger, K. C. Mandal, C. C. Noblitt, S. A. Speakman, K. Rademaker, S. A. Payne

Faculty Publications

No abstract provided.

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Size Evaluation Of Corrosion Precursor Pitting Using Near-Field Millimeter Wave Nondestructive Testing Methods, Mohammad Tayeb Ahmad Ghasr, Brian D. Carroll, Sergey Kharkovsky, R. Zoughi, R. Austin Apr 2005

Size Evaluation Of Corrosion Precursor Pitting Using Near-Field Millimeter Wave Nondestructive Testing Methods, Mohammad Tayeb Ahmad Ghasr, Brian D. Carroll, Sergey Kharkovsky, R. Zoughi, R. Austin

Electrical and Computer Engineering Faculty Research & Creative Works

Early detection of corrosion precursor pitting and estimation of its overall dimensions directly affects the required effort and cost associated with repair and maintenance of critical aircraft structural components. The magnitude and phase of a reflected signal from a pitting are directly related to its dimensions. This paper presents a millimeter wave probe and a sizing procedure used to detect and evaluate overall pitting dimensions.

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Deconvolution Analysis Of Laser Pulse Profiles From 3-D Ladar Temporal Returns, Michael D. Walter Mar 2005

Deconvolution Analysis Of Laser Pulse Profiles From 3-D Ladar Temporal Returns, Michael D. Walter

Theses and Dissertations

Three-dimensional laser imaging systems offer important advantages for battlefield applications, such as night-time targeting and tactical reconnaissance. Recently developed technologies used by coherent detection systems that collect temporally resolved images include arrays of Avalanche Photo-Diodes (APD), Geiger mode APDs, and photo-diodes. Frequently, LADAR systems produce waveforms from each detector that characterize the convolution of the transmitted laser pulse with the target surface. The pulse convolution generates uncertainty as to the precise location of a target surface, which can severely impact various weapon systems' targeting capability. This work analyzes two deconvolution techniques: Wiener filtering and an iterative process derived from the …

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Using Liquid Crystal Spatial Light Modulators For Closed Loop Tracking And Beam Steering With Phase Holography, Michael J. Perry Mar 2005

Using Liquid Crystal Spatial Light Modulators For Closed Loop Tracking And Beam Steering With Phase Holography, Michael J. Perry

Theses and Dissertations

Optical Phased Array (OPA) technology offers advantages in the reduction of size, weight, and power of optical steering devices. Nematic liquid crystal (LC) spatial light modulators (SLMs) have been studied as a potential candidate for building non-mechanical OPAs. They can steer a laser beam and split the beam into multiple beams. This thesis builds upon the prior research showing each split beam can be individually controlled, including variation in intensity. A closed loop tracking scenario shows the flexibility of the SLM by tracking and stabilizing an incoming beam. Results show that applying a phase grating to the SLM has limitations …

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Electro-Optic Beam Steering Using Domain Engineered Lithium Tantalate, Daren J. Chauvin Mar 2005

Electro-Optic Beam Steering Using Domain Engineered Lithium Tantalate, Daren J. Chauvin

Theses and Dissertations

The operation of a 14-channel five stage electro-optic beam steering device was studied. Beam deflection scanned from 0° to 10.1° was demonstrated. The maximum angle is within 0.3% of design. Many laser systems in operation today implement mechanical beam steering methods that are often expensive in terms of cost, weight and power. They are slow and subject to wear and vibration. A non-inertial beam scanning mechanism, such as one based on the device studied in this research could enhance the performance of these systems. The device studied here is fabricated in LiTaO3 using micro-patterned domain reversal. The 14 channels …

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Computational Model Of One-Dimensional Dielectric Barrier Discharges, Krista G. Marchand Mar 2005

Computational Model Of One-Dimensional Dielectric Barrier Discharges, Krista G. Marchand

Theses and Dissertations

As theory lags experiment for dielectric barrier discharge flow control, two different computational methods are implemented to give further insight into characteristics of the dielectric barrier discharge (DBD). A one-dimensional fluid model of a surface-type dielectric barrier discharge is created using He as the background gas. This simple model, which only considers ionizing collisions and recombination in the electropositive gas, creates an important framework for future studies into the origin of experimentally observed flow-control effects of the DBD. The two methods employed in this study include the semi-implicit sequential algorithm and the fully implicit simultaneous algorithm. The first involves consecutive …

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Determination Of Structure From Motion Using Aerial Imagery, Paul R. Graham Mar 2005

Determination Of Structure From Motion Using Aerial Imagery, Paul R. Graham

Theses and Dissertations

The structure from motion process creates three-dimensional models from a sequence of images. Until recently, most research in this field has been restricted to land-based imagery. This research examines the current methods of land-based structure from motion and evaluates their performance for aerial imagery. Current structure from motion algorithms search the initial image for features to track though the subsequent images. These features are used to create point correspondences between the two images. The correspondences are used to estimate the motion of the camera and then the three-dimensional structure of the scene. This research tests current algorithms using synthetic data …

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Daytime Detection Of Space Objects, Alistair D. Funge Mar 2005

Daytime Detection Of Space Objects, Alistair D. Funge

Theses and Dissertations

Space Situational Awareness (SSA) requires repeated object updates for orbit accuracy. Detection of unknown objects is critical. A daytime model was developed that evaluated sun flares and assessed thermal emissions from space objects. Iridium satellites generate predictable sun glints. These were used as a model baseline for daytime detections. Flares and space object thermal emissions were examined for daytime detection. A variety of geometric, material and atmospheric characteristics affected this daytime detection capability. In a photon noise limited mode, simulated Iridium flares were detected. The peak Signal-to- Noise Ratios (SNR) were 6.05e18, 9.63e5, and 1.65e7 for the nighttime, daytime and …

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The Use Of X-Ray Pulsars For Aiding Gps Satellite Orbit Determination, Dennis W. Woodfork Ii Mar 2005

The Use Of X-Ray Pulsars For Aiding Gps Satellite Orbit Determination, Dennis W. Woodfork Ii

Theses and Dissertations

This research proposes the use of an existing "signal of opportunity" - namely x-ray pulsars - to improve the accuracy and robustness of the GPS satellite and clock estimation algorithm. Improvement in satellite and clock accuracy results in a direct benefit to the user. A simulation has been developed to determine the effects of using x-ray pulsar measurements on the GPS Operational Control Segment. The epoch-specific position, velocity, and clock errors of all GPS satellites in the constellation were estimated using both pseudoranges and time-difference-of-arrival (TDOA) measurements from pulsars. The primary measure of accuracy is a constellation Signal-In-Space Range Error …

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Noise Estimation In The Presence Of Bpsk Digital Burst Transmissions, Susan E. Bettison Mar 2005

Noise Estimation In The Presence Of Bpsk Digital Burst Transmissions, Susan E. Bettison

Theses and Dissertations

This research explores noise estimation techniques in an attempt to improve upon a previously developed digital burst transmission Binary Phase Shift Keyed (BPSK) demodulator. The demodulator success is dependent on the accuracy of the estimate of Power Spectral Density (PSD) of the unknown noise. Given a discrete time signal transformed into the frequency domain, the research seeks to determine if it is possible to effectively estimate the PSD of the unknown noise. The demodulator was developed using a new signal model for digital burst transmissions based on linear spectral subspace theory. Using this model and the redundancy properties of BPSK …

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Preparation And Characterization Of Lini_(0.85)Co_(0.10)(Timg)_(0.025)O_2 As Cathode Materials For Lithium-Ion Batteries, Xian-Jun Zhu, Hong-Hao Chen, Hui Zhan, Dai-Ling Yang, Yun-Hong Zhou Feb 2005

Preparation And Characterization Of Lini_(0.85)Co_(0.10)(Timg)_(0.025)O_2 As Cathode Materials For Lithium-Ion Batteries, Xian-Jun Zhu, Hong-Hao Chen, Hui Zhan, Dai-Ling Yang, Yun-Hong Zhou

Journal of Electrochemistry

Cathode material of LiNi_(0.85)Co_(0.10)(TiMg)_(0.025)O_2 were prepared by solid state reaction at 725℃ for 24 h from LiOH·H_2O, Ni_2O_3, Co_2O_3, TiO_2 and Mg(OH)_2 under flowing oxygen, and were characterized by TG-DTA, XRD, SEM and electrochemical tests. Effort to simultaneously doped LiNiO_2 with Co-Ti-Mg has been tried to improve the cathode performance. The results show that co-doping definitely has a large beneficial effect in increasing the capacity (182.7mAh/g of the first discharge capacity for LiNi_(0.85)Co_(0.10)(TiMg)_(0.025)O_2) and cycling behavior (175.5 mAh/g after 10 cycles). This cathode materials can be applied for lithium-ion batteries.

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Application Of Carbon Paste Electrode On The Electrogenerative-Leaching Process Of Sulfide Minerals, Shao-Fen Wang Feb 2005

Application Of Carbon Paste Electrode On The Electrogenerative-Leaching Process Of Sulfide Minerals, Shao-Fen Wang

Journal of Electrochemistry

The cyclic voltammetry curves of sulfide mineral electrodes or corresponding carbon paste electrodes in NaCl electrolytes have been obtained in this study. The experimental results indicate that acetylene black (revealed) the electro-catalytic propertyin the electrogenerative-leaching process of sulfide minerals. The output currentand potential of carbon paste electrodes were increased to some degrees while the activation energies were lower.

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Anodic Polarization Behaviors Of Carbon Steel In Bicarbonate Solution, Jing-Mao Zhao, Yu Zuo Feb 2005

Anodic Polarization Behaviors Of Carbon Steel In Bicarbonate Solution, Jing-Mao Zhao, Yu Zuo

Journal of Electrochemistry

The anodic polarization curves of mild steel were measured in sodium bicarbonate solution of various concentrations, and the surface products were analyzed by XPS. Two anodic current peaks and two passive zones are observed in all the curves. When HCO_3~- ions concentration is below 0.1mol/L, the two peaks are so close that the first passive zone is difficult to be observed. When HCO_3~- ions concentration is above 0.1 mol/L, the first peak appears clear, while the second becomes smaller. The XPS results indicate that the out layer of film formed at a higher potential is mainly composed of Fe_2O_(3,) and …

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Influence Of Rare Earth Oxide On The Performance Of Secondary Zinc Electrodes, Xian-Ling Meng, Hua-Bin Yang, Jun-Hong Wang, Zuo-Xiang Zhou Feb 2005

Influence Of Rare Earth Oxide On The Performance Of Secondary Zinc Electrodes, Xian-Ling Meng, Hua-Bin Yang, Jun-Hong Wang, Zuo-Xiang Zhou

Journal of Electrochemistry

Influence of La(OH)_(3 )or Ce(OH)_3in secondary zinc electrode was investigated by the cyclic voltammetry, potentiodynamic polarizationand potentiostatic polarization tests and influence of La_2O_3or CeO_2in the charge/discharge performance of Zn/Ni battery was studied by galvanostatic charge/discharge experiment. The results showed that the film of rare earth hydroxide prevented the zincate species from transferring toward solution, enhanced hydrogen overpotential and decreased thecorrosion current density (i_(corr)), and therefore inhibited zinc corrosion. The potentiostatic polarization results at100mV overpotential showed thatLa(OH)_3or Ce(OH)_3coated on the zinc electrode effectively suppressed the zinc dendrite growth. The La_2O_(3 )or CeO_2addition to the calcium zincate electrode improved the cycle performance …

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Research On Phenol Wastewater Treatment By Electrochemical Oxidation, Tian-Cheng Li, Shen-Lin Zhu Feb 2005

Research On Phenol Wastewater Treatment By Electrochemical Oxidation, Tian-Cheng Li, Shen-Lin Zhu

Journal of Electrochemistry

Electrochemical oxidation is an effective technology for the phenol wastewater treatment, and the anode properties are important to the electrochemical oxidationefficiency. The over-potentials of oxygen evolution have been measured for thestainless steel, feasible graphite and SnO_2/Ti anode respectively. Moreover, the synthetic phenol wastewater was treated by the electrochemical oxidation with the stainless steel or feasible graphite anodes. The experimental results showed that the order of the over-potential is SnO_2/Ti > graphite > stainless steel; meanwhile, the COD values of purified water were approaching to or less than 100 mg·L~(-1), and the phenol concentrations in the purified water were below 0.5 mg·L~(-1).

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Studies On Polymer Light-Emitting Electrochemical Cells ——Introduction Of The Studies On The Electrochemistry Of Conducting Polymers In Cas Key Laboratory Of Organic Solids (Ⅱ), Yong-Fang Li Feb 2005

Studies On Polymer Light-Emitting Electrochemical Cells ——Introduction Of The Studies On The Electrochemistry Of Conducting Polymers In Cas Key Laboratory Of Organic Solids (Ⅱ), Yong-Fang Li

Journal of Electrochemistry

Polymer light-emitting electrochemical cell (LEC) is composed of a conjugated polymer(CP) / polymer electrolyte blend film sandwiched between an ITO anode and an Al cathode. When a bias voltage greater than Eg/e (where Eg is the energy gap of the CP, e is the electron charge) is applied on the two electrodes, the CP in the polymer blend film at the anode side will be oxidized (to form a p-doped region), and that at the cathode side will be reduced (to form a n-doped region), then a p-i-n junction will be produced. Light-emission occurs in the intrinsic region between the …

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A Study Of Metal Borides As High Capacity Anode Materials For Aqueous Primary Batteries, Ya-Dong Wang, Xin-Ping Ai, Han-Xi Yang Feb 2005

A Study Of Metal Borides As High Capacity Anode Materials For Aqueous Primary Batteries, Ya-Dong Wang, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

The transition metal borides VB_2 and TiB_2 were tested as high capacity anode materials and their electrochemical behaviors were studied by cyclic voltammetry and discharge measurements. The experimental results indicated that transition metal borides VB_2 and TiB_2 electrodes can deliver exceptionally high discharge capacity of over 3100 mAH/g and 1 600 mAH/g respectively, corresponding to 11- and 6-electron oxidation reaction, although their parent elements V, Ti and boron, are almost completely electrochemically inert. The different electrochemical activitis were probably due to the electrochemical activation of boron, which clamp the potential to passivation for Ti and activity for V.

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The Fabrication And Electrochemical Studies On Carbon Nanotube Array Electrodes, Quan-Yong Gao, Jing Zhang, Yangyong Yangyong Feb 2005

The Fabrication And Electrochemical Studies On Carbon Nanotube Array Electrodes, Quan-Yong Gao, Jing Zhang, Yangyong Yangyong

Journal of Electrochemistry

An improved technique for fabrication of carbon nanotube array electrodes has been proposed in this work. Firstly, carbon nanotubes (CNs) array electrodes were prepared by combsination of Chemical Vapor Decomposition (CVD) method and sputtering techniques in anodized aluminum oxide (AAO) membrane. The CNs/AAO was immersed into HF solution to remove the barrier layer. Controlling the immersing time, the CNs array electrodes with different length contacted with electrolyte can be prepared. The morphology of CNs array electrodes was observed by SEM. The electrochemical properties of CNs array electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetric curves of …

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Preparation Of Poly ( Bromophenol Blue ) Modified Glassy Carbon Electrode And Its Electrocatalytic Activity, Wei Chen, Hong-Bin Luo, Xin-Hua Lin Feb 2005

Preparation Of Poly ( Bromophenol Blue ) Modified Glassy Carbon Electrode And Its Electrocatalytic Activity, Wei Chen, Hong-Bin Luo, Xin-Hua Lin

Journal of Electrochemistry

A film of poly ( bromophenol blue ) was formed on a glassy carbon electrode by using cyclic voltammetry. A stable film could be obtained with a potential range from -1.0V to +1.8V(vs.Ag/AgCl). The experimental results showed that the poly ( bromophenol blue ) modified glassy carbon electrode could catalyse the oxidation of ascorbic acid. It decreased the oxidation potential by about 270mV but increased the peak current. Meanwhile, this electrode showed a good linear current response for the ascorbic acid range from 2.5 to 250 (g/mL.)

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Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, Pingan He, Jagannathan Sarangapani Feb 2005

Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN) -based output feedback controller with magnitude constraints is designed to deliver a desired tracking performance for a class of multi-input-multi-output (MIMO) discrete-time strict feedback nonlinear systems. Reinforcement learning in discrete time is proposed for the output feedback controller, which uses three NN: 1) a NN observer to estimate the system states with the input-output data; 2) a critic NN to approximate certain strategic utility function; and 3) an action NN to minimize both the strategic utility function and the unknown dynamics estimation errors. The magnitude constraints are manifested as saturation nonlinearities in the output feedback …

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Optical Wave Propagation In Discrete Waveguide Arrays, Jared Hudock Jan 2005

Optical Wave Propagation In Discrete Waveguide Arrays, Jared Hudock

Electronic Theses and Dissertations

The propagation dynamics of light in optical waveguide arrays is characteristic of that encountered in discrete systems. As a result, it is possible to engineer the diffraction properties of such structures, which leads to the ability to control the flow of light in ways that are impossible in continuous media. In this work, a detailed theoretical investigation of both linear and nonlinear optical wave propagation in one- and two-dimensional waveguide lattices is presented. The ability to completely overcome the effects of discrete diffraction through the mutual trapping of two orthogonally polarized coherent beams interacting in Kerr nonlinear arrays of birefringent …

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Liquid Crystal Optics For Communications, Signal Processing And 3-D Microscopic Imaging, Sajjad Khan Jan 2005

Liquid Crystal Optics For Communications, Signal Processing And 3-D Microscopic Imaging, Sajjad Khan

Electronic Theses and Dissertations

This dissertation proposes, studies and experimentally demonstrates novel liquid crystal (LC) optics to solve challenging problems in RF and photonic signal processing, freespace and fiber optic communications and microscopic imaging. These include free-space optical scanners for military and optical wireless applications, variable fiber-optic attenuators for optical communications, photonic control techniques for phased array antennas and radar, and 3-D microscopic imaging. At the heart of the applications demonstrated in this thesis are LC devices that are non-pixelated and can be controlled either electrically or optically. Instead of the typical pixel-by-pixel control as is custom in LC devices, the phase profile across …

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Refractive Indices Of Liquid Crystals And Their Applications In Display And Photonic Devices, Jun Li Jan 2005

Refractive Indices Of Liquid Crystals And Their Applications In Display And Photonic Devices, Jun Li

Electronic Theses and Dissertations

Liquid crystals (LCs) are important materials for flat panel display and photonic devices. Most LC devices use electrical field-, magnetic field-, or temperature-induced refractive index change to modulate the incident light. Molecular constituents, wavelength, and temperature are the three primary factors determining the liquid crystal refractive indices: ne and no for the extraordinary and ordinary rays, respectively. In this dissertation, we derive several physical models for describing the wavelength and temperature effects on liquid crystal refractive indices, average refractive index, and birefringence. Based on these models, we develop some high temperature gradient refractive index LC mixtures for photonic applications, such …

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Signal Flow Analysis, Partha P. Banerjee Jan 2005

Signal Flow Analysis, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Signal flow graphs are a viable alternative to block diagrammatic representation of a system. What makes signal flow graphs attractive is that certain features from graph theory can be applied to the simplification and the synthesis of complex systems.

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