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Electrical and Computer Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

Nanomanipulation Using Atomic Force Microscope With Drift Compensation, Qinmin Yang, Jagannathan Sarangapani Jun 2006

Nanomanipulation Using Atomic Force Microscope With Drift Compensation, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an atomic force microscope (AFM) based force controller to push nanoparticles on the substrates since it is tedious for human. A block phase correlation-based algorithm is embedded into the controller for compensating the thermal drift during nanomanipulation. Further, a neural network (NN) is employed to approximate the unknown nanoparticle and substrate contact dynamics including the roughness effects. Using the NN-based adaptive force controller the task of pushing nanoparticles is demonstrated. Finally, using the Lyapunov-based stability analysis, the uniform ultimately boundedness (UUB) of the closed-loop signals is demonstrated

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Inertia And Memory In Ambiguous Visual Perception, J. B. Gao, V. A. Billock, I. Merk, W. W. Tung, K. D. White, J. G. Harris, V. P. Roychowdhury Jun 2006

Inertia And Memory In Ambiguous Visual Perception, J. B. Gao, V. A. Billock, I. Merk, W. W. Tung, K. D. White, J. G. Harris, V. P. Roychowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Perceptual multistability during ambiguous visual perception is an important clue to neural dynamics. We examined perceptual switching during ambiguous depth perception using a Necker cube stimulus, and also during binocular rivalry. Analysis of perceptual switching time series using variance-sample size analysis, spectral analysis and time series shuffling shows that switching times behave as a 1/f noise and possess very long-range correlations. The long memory feature contrasts sharply with the traditional satiation models of multistability, where the memory is not incorporated, as well as with recently published models of multistability and neural processing, where memory is excluded. On the other hand, …

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A Field Reconstruction Method For Optimal Excitation Of Permanent Magnet Synchronous Machines, Weidong Zhu, Babak Fahimi, Steve Pekarek Jun 2006

A Field Reconstruction Method For Optimal Excitation Of Permanent Magnet Synchronous Machines, Weidong Zhu, Babak Fahimi, Steve Pekarek

Electrical and Computer Engineering Faculty Research & Creative Works

Vibration caused by torque ripple and radial force harmonics is a concern in many applications of permanent magnet synchronous machines (PMSMs). Alternative methods of machine design and/or stator excitation to minimize torque ripple have received considerable attention in recent years. Comparatively, methods to minimize radial force harmonics have received less attention. in this paper, a field reconstruction (FR) method is derived that provides a designer with the capability to rapidly determine the radial and tangential components of force under arbitrary stator excitation. using the field reconstruction method, stator current waveforms that minimize the ripple of both torque and radial force …

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Adaptive Neural Network Control And Wireless Sensor Network Based Localization For Uav Formation, H. Wu, Jagannathan Sarangapani Jun 2006

Adaptive Neural Network Control And Wireless Sensor Network Based Localization For Uav Formation, H. Wu, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

We consider a team of unmanned aerial vehicles (UAV's) equipped with sensors and motes for wireless communication for the task of navigating to a desired location in a formation. First a neural network (NN)-based control scheme is presented that allows the UAVs to track a desired position and orientation with reference to the neighboring UAVs or obstacles in the environment. Second, we discuss a graph theory-based scheme for discovery, localization and cooperative control. The purpose of the NN cooperative controller is to achieve and maintain the desired formation shape in the presence of unmodeled dynamics and bounded unknown disturbances. Numerical …

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A Time-To-First Spike Cmos Image Sensor With Coarse Temporal Sampling, Qiang Luo, John G. Harris, Zhiliang J. Chen Jun 2006

A Time-To-First Spike Cmos Image Sensor With Coarse Temporal Sampling, Qiang Luo, John G. Harris, Zhiliang J. Chen

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional voltage-based CMOS image sensors inherently have a dynamic range of about 60 dB. To extend the dynamic range, a two-degree of freedom time-based CMOS image sensor is proposed. Instead of reading analog voltages off chip, a time representation is used to record when the photodetector voltage passes a timing-varying threshold. The time measurements are combined with the reference voltage waveform to reconstruct the image. Experimental results on a prototype 32 x 32-pixel array CMOS image sensor verify that the two-degree of freedom sampling technique is feasible for ultra-wide dynamic range imaging. A measured 115 dB dynamic range at 30 …

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Time-Delay Neural Network Based Predictions Of Elephant Distribution In A South African Game Reserve, Parviz Palangpour, Ganesh K. Venayagamoorthy, Kevin Duffy May 2006

Time-Delay Neural Network Based Predictions Of Elephant Distribution In A South African Game Reserve, Parviz Palangpour, Ganesh K. Venayagamoorthy, Kevin Duffy

Electrical and Computer Engineering Faculty Research & Creative Works

A large portion of South Africa's elephant population can be found on small wildlife reserves. When confined to enclosed reserves the elephant densities are much higher than observed in the wild. The large nutritional demands and destructive foraging behavior of elephants threaten rare species of vegetation. If conservation management is to protect threatened species of vegetation, knowing how long elephants will stay in one area of the reserve as well as which area they will move to next is essential. The goal of this study is to train an artificial neural network to predict an elephant herd's next position in …

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Comparison Of Pso And Ga For K-Node Set Reliability Optimization Of A Distributed System, G. A. Bakare, I. N. Chiroma, Ganesh K. Venayagamoorthy May 2006

Comparison Of Pso And Ga For K-Node Set Reliability Optimization Of A Distributed System, G. A. Bakare, I. N. Chiroma, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Particle Swarm Optimization (PSO), as a novel evolutionary computing technique, has succeeded in many continuous problems, but quite a little research on discrete problem especially combinatorial optimization problem has been reported. In this paper, a discrete PSO algorithm is proposed to solve a typical combinatorial optimization problem: K-Node Set Reliability (KNR) optimization of a distributed computing system (DCS) which is a well-known NP-hard problem is presented. It computes the reliability of a subset of network nodes of a DCS such that the reliability is maximized and specified capacity constraint is satisfied. The feasibility of the proposed algorithm is demonstrated on …

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An Efficient Approach For Power Delivery Network Design With Closed-Form Expressions For Parasitic Interconnect Inductances, Chen Wang, Jingkun Mao, Giuseppe Selli, Shaofeng Luan, Lin Zhang, Jun Fan, David Pommerenke, Richard E. Dubroff, James L. Drewniak May 2006

An Efficient Approach For Power Delivery Network Design With Closed-Form Expressions For Parasitic Interconnect Inductances, Chen Wang, Jingkun Mao, Giuseppe Selli, Shaofeng Luan, Lin Zhang, Jun Fan, David Pommerenke, Richard E. Dubroff, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation of a dc power delivery network, consisting of a multilayer PCB using area fills for power and return, involves the distributed behavior of the power/ground planes and the parasitics associated with the lumped components mounted on it. Full-wave methods are often employed to study the power integrity problem. While full-wave methods can be accurate, they are time and memory consuming. The cavity model of a rectangular structure has previously been employed to efficiently analyze the simultaneous switching noise (SSN) in the power distribution network. However, a large number of modes in the cavity model are needed to accurately simulate …

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Obstacle Avoidance In Collective Robotic Search Using Particle Swarm Optimization, Lisa L. Smith, Ganesh K. Venayagamoorthy, Phillip G. Holloway May 2006

Obstacle Avoidance In Collective Robotic Search Using Particle Swarm Optimization, Lisa L. Smith, Ganesh K. Venayagamoorthy, Phillip G. Holloway

Electrical and Computer Engineering Faculty Research & Creative Works

Particle Swarm Optimization (PSO) has been demonstrated to be a useful technique in target search applications such as Collective Robotic Search (CRS). A group of unmanned mobile robots are able to locate a specified target in a high risk environment with extreme efficiency when driven by an optimized PSO algorithm. This paper presents an algorithm for obstacle avoidance with the PSO approach applied to navigate robots in collective search applications. Obstacles represented by basic geometric shapes to simulate perilous ground terrain are introduced to the search area. Results are presented to show that PSO algorithm based CRS is able to …

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Modeling Of The Ic's Switching Currents On The Power Bus Of A High Speed Digital Board, Mauro Lai, James L. Drewniak, Vittorio Ricchiuti, Antonio Orlandi, Giulio Antonini May 2006

Modeling Of The Ic's Switching Currents On The Power Bus Of A High Speed Digital Board, Mauro Lai, James L. Drewniak, Vittorio Ricchiuti, Antonio Orlandi, Giulio Antonini

Electrical and Computer Engineering Faculty Research & Creative Works

When the performances of the electronic technology increase (higher frequencies, more power, lover power supply, faster transistors, reduced chip dimensions), designing electronic equipment becomes more challenging for the electronic engineers. Signal and power integrity on board become of paramount importance. One of the main causes of board malfunctions and electromagnetic radiation is the simultaneous switching noise (SSN) due to the integrated circuits soldered on the board. The paper proposes two simple procedures to model the SSN, so to evaluate its effects in any point of the board.

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Optimal Allocation Of A Statcom In A 45 Bus Section Of The Brazilian Power System Using Particle Swarm Optimization, J. C. Hernandez, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley May 2006

Optimal Allocation Of A Statcom In A 45 Bus Section Of The Brazilian Power System Using Particle Swarm Optimization, J. C. Hernandez, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces the application of Particle Swarm Optimization (PSO) to solve the optimal allocation of a STATCOM in a 45 bus system which is part of the Brazilian power network. The criterion used in finding the optimal location is based on the voltage profile of the system, i.e. the voltage deviation at each bus, with respect to its optimum value, is minimized. In order to test the performance of the PSO algorithm in this particular application, different approaches for inertia weight are investigated; also different values of acceleration constants, number of iterations and maximum velocity are considered. A sensitivity …

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Overdistention Operation Of Cascaded Multilevel Inverters, Xiaomin Kou, Keith Corzine, M. W. Wielebski May 2006

Overdistention Operation Of Cascaded Multilevel Inverters, Xiaomin Kou, Keith Corzine, M. W. Wielebski

Electrical and Computer Engineering Faculty Research & Creative Works

In the past decade, the multilevel power converter has transitioned from an experimental concept to a standard product of many medium-voltage drive manufacturers. By utilizing small voltage steps, the multilevel topology offers higher power quality, higher voltage capability, lower switching losses, and improved electromagnetic compatibility over standard topologies. Recently, several researchers have focused on the cascaded multilevel inverter whereby two multilevel inverters are series connected to a motor load by splitting the neutral connection. The resulting performance is exceptional in terms of power quality since the overall number of voltage levels is effectively the product of the two cascaded inverters. …

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Evaluation Of Alternative Evolutionary Programming Techniques For Optimization Of An Automotive Alternator, Andreas C. Koenig, Joshua M. Williams, Steven D. Pekarek May 2006

Evaluation Of Alternative Evolutionary Programming Techniques For Optimization Of An Automotive Alternator, Andreas C. Koenig, Joshua M. Williams, Steven D. Pekarek

Electrical and Computer Engineering Faculty Research & Creative Works

One of the primary design requirements of automotive generation systems is maximizing power density subject to the constraint of minimizing the overall system cost. However, with the progress made in the reduction of automotive drive train noise, the torque ripple of the generator has been found to be a dominant noise source under idle conditions at high electrical loads. Thus, an added design constraint is the minimization of the torque ripple produced by the machine. in order to evaluate alternative machine designs (and select an optimal), numerical tools are typically applied. in this research, a focus is placed on the …

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Extraction Of Dispersive Material Parameters Using Vector Network Analyzers And Genetic Algorithms, Jianmin Zhang, Marina Koledintseva, David Pommerenke, James L. Drewniak, Konstantin Rozanov, Giulio Antonini, Antonio Orlandi Apr 2006

Extraction Of Dispersive Material Parameters Using Vector Network Analyzers And Genetic Algorithms, Jianmin Zhang, Marina Koledintseva, David Pommerenke, James L. Drewniak, Konstantin Rozanov, Giulio Antonini, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

A novel method to extract dispersive properties for dielectrics over a wide frequency range is proposed. This method is based on measuring scattering parameters for planar transmission lines and applying genetic algorithms. The scattering parameters are converted into ABCD matrix parameters. The complex propagation constant of the TEM wave inside the line is obtained from A-parameters of the ABCD matrix. For planar transmission lines, analytical or empirical formulas for dielectric loss,conductor loss, anaphase constant are known. The genetic algorithm is then used to extract the Debye parameters for the dielectric substrates. FDTD modeling is used to verify the dispersive parameter …

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Automated Oxidase-Coupled Amperometric Microsensor With Integrated Electrochemical Actuation System For Continuous Sensing Of Saccharoids, Yadunandana Yellambalase, Jongwon Park, Chang-Soo Kim, Minsu Choi, Nohpill Park, Fabrizio Lombardi Apr 2006

Automated Oxidase-Coupled Amperometric Microsensor With Integrated Electrochemical Actuation System For Continuous Sensing Of Saccharoids, Yadunandana Yellambalase, Jongwon Park, Chang-Soo Kim, Minsu Choi, Nohpill Park, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

Recent developments for biosensors have been mainly focused on miniaturization and exploratory use of new materials. It should be emphasized that the absence of a novel "in-situ self-calibration/diagnosis technique" that is not connected to an external apparatus is a key obstacle to the realization of a biosensor for continuous use with minimum attendance. To address this deficiency, a novel needle-type biosensor system with fully automated operations is being developed, in which a novel oxidase-coupled amperometric sensor with oxygen depleting/generating actuator is interfaced with an electrochemical instrument and a perfusion system. Labview virtual instrument has been also developed to oversee the …

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Dual-Polarized Microwave Near-Field Reflectometer For Non-Invasive Inspection Of Carbon Fiber Reinforced Polymer (Cfrp) Strengthened Structures, Sergey Kharkovsky, Adam C. Ryley, Vivian Stephen, R. Zoughi Apr 2006

Dual-Polarized Microwave Near-Field Reflectometer For Non-Invasive Inspection Of Carbon Fiber Reinforced Polymer (Cfrp) Strengthened Structures, Sergey Kharkovsky, Adam C. Ryley, Vivian Stephen, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Carbon fiber reinforced polymer (CFRP) composites are increasingly being used in strengthening structures of civil infrastructures, aerospace and automotive industries. Subsequent to the application of CFRP, detection and evaluation of the structural integrity of the member becomes a critical issue. Microwave non-invasive inspection techniques have been successfully used for inspecting these structures. A novel inspection system with a dual-polarized microwave near-field waveguide probe for detecting defects such as disbond between CFRP laminates and strengthened structures is presented. It is shown that this system provides automatic removal of the influence of undesired standoff distance (or surface roughness) variations. It may simultaneously …

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Inspection Of Spray On Foam Insulation (Sofi) Using Microwave And Millimeter Wave Synthetic Aperture Focusing And Holography, Joseph Toby Case, Frank L. Hepburn, R. Zoughi Apr 2006

Inspection Of Spray On Foam Insulation (Sofi) Using Microwave And Millimeter Wave Synthetic Aperture Focusing And Holography, Joseph Toby Case, Frank L. Hepburn, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The Space Shuttle Columbia's catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking and significantly damaging the left wing of the orbiter, which may have been due to a flawed section of SOFI. Microwave and millimeter wave nondestructive evaluation (NDE) methods have shown great potential detecting anomalies in SOFI such as small air voids using a horn and lens in a (real) focused configuration. Synthetic focusing methods may also be used to detect air voids in SOFI and may additionally offer the ability to locate the defect in …

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Jitter Analysis Of Pwm Scheme In High Speed Serial Link, Rui Tang, Yong-Bin Kim, Minsu Choi, Fabrizio Lombardi Apr 2006

Jitter Analysis Of Pwm Scheme In High Speed Serial Link, Rui Tang, Yong-Bin Kim, Minsu Choi, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a jitter analysis method for PWM (pulse width modulation) scheme in high-speed serial links. The data rate of PWM with N different pulse widths (PWM-N) scheme is (log2N) x (symbol rate). However it increases the timing jitter of the transmitted signal. The timing jitter is determined by the pulse widths of PWM symbols and the characteristics of the communication channel. The analysis of the first-order systems and the second-order systems demonstrates that data dependent jitter (DDJ) strongly depends on the -3dB frequency and the damping ratio of the systems. The proposed jitter analysis method makes …

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High Accuracy Disbond Thickness Estimation Scheme Employing Multiple-Frequency Near-Field Microwave Measurements, Mohamed A. Abou-Khousa, R. Zoughi Apr 2006

High Accuracy Disbond Thickness Estimation Scheme Employing Multiple-Frequency Near-Field Microwave Measurements, Mohamed A. Abou-Khousa, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Microwave nondestructive evaluation (NDE) techniques have shown great potential for disbond detection in multi-layer dielectric structures. However, a quantitative disbond thickness estimation scheme has not been introduced yet. In this paper, we propose a maximum-likelihood (ML) disbond thickness estimation scheme utilizing multiple independent measurements obtained at different frequencies. By simulations and experiments, we show that the proposed scheme produces highly accurate disbond thickness estimates.

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A Time-Based Vlsi Potentiostat For Ion Current Measurements, Harpreet S. Narula, John G. Harris Apr 2006

A Time-Based Vlsi Potentiostat For Ion Current Measurements, Harpreet S. Narula, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A time-based CMOS integrated potentiostatic control circuit has been designed and fabricated. The design maintains a constant bias potential between the reference and working electrodes for an amperometric chemical sensor. A technique of converting input currents into time for amperometric measurements is proposed. This technique eliminates current amplifying circuitry, reduces matching problems, and increases dynamic range while saving on area and power consumption. Redox currents ranging from 1 pA to 200 nA can be measured with a maximum nonlinearity of ±0.1% over this range. The design can be used to generate cyclic voltammograms for an electrochemical reaction by sweeping the …

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Frequency-Selective Power Transducers "Hexagonal Ferrite Resonator-Semiconductor Element", Marina Koledintseva Mar 2006

Frequency-Selective Power Transducers "Hexagonal Ferrite Resonator-Semiconductor Element", Marina Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

The transducers studied herein allow for frequency-selective measurement of mm-wave power parameters. Frequency selectivity is assured by a monocrystalline hexagonal ferrite resonator (HFR). The HFR is in direct contact with a semiconductor element (SE)—an unpackaged Hall-element, or a chip transistor (or diode). Power absorbed by the HFR at the ferromagnetic resonance converts to heat, and the heat flux penetrates through the current-carrying SE. A number of thermo/electro/magnetic phenomena accompany the Hall-effect in a semiconductor and cause a voltage in addition to the Hall-effect voltage. The conversion coefficient of a transducer is analyzed using the power balance equation. Some experimental results …

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Non-Unity Active Pfc Methods For Filter Size Optimization, Yongxiang Chen, Jonathan W. Kimball, Philip T. Krein Mar 2006

Non-Unity Active Pfc Methods For Filter Size Optimization, Yongxiang Chen, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Active power factor correction seeks to obtain unity power factor and sinusoidal line currents. Optimized nonsinusoidal line currents reduce filter capacitor requirements with a nonunity target power factor. Implementation methods are presented that permit reduced power factor to be traded off against filter size in a nearly optimum manner. A simple waveform shape can reduce filter component size by about 40% in active PFC converters at the same level of complexity as in conventional PFC designs while yielding power factor as high as 0.9. Two approximate methods to generate appropriate shapes are presented. They offer direct practical implementation of nonunity …

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Power Absorption Of Near Field Of Elementary Radiators In Proximity Of A Composite Layer, Marina Koledintseva, Poorna Chander Ravva, Jingyu Huang, James L. Drewniak, M. M. Sabirov, V. V. Bodrov, I. V. Sourkova, V. I. Sourkov Mar 2006

Power Absorption Of Near Field Of Elementary Radiators In Proximity Of A Composite Layer, Marina Koledintseva, Poorna Chander Ravva, Jingyu Huang, James L. Drewniak, M. M. Sabirov, V. V. Bodrov, I. V. Sourkova, V. I. Sourkov

Electrical and Computer Engineering Faculty Research & Creative Works

Near-field behavior of elementary electric and magnetic dipoles close to a plane layer (or layers) of engineered composite materials is analyzed using the rigorous analytical approach. Some results of computations are represented for composite media containing conductive inclusions. These composites provide shielding mainly due to absorption of electromagnetic energy. The effect of conductivity of inclusions and their geometry (through their aspect ratio) on the absorption and radiation efficiency of a radiator near composite layers is analyzed.

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Millimeter Wave Imaging Of Corrosion Under Paint: Comparison Of Two Probes, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, Matthew O'Keefe, Ajay Padwal, Donald D. Palmer Mar 2006

Millimeter Wave Imaging Of Corrosion Under Paint: Comparison Of Two Probes, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, Matthew O'Keefe, Ajay Padwal, Donald D. Palmer

Electrical and Computer Engineering Faculty Research & Creative Works

Critical aircraft structures are susceptible to harsh environmental conditions that cause corrosion of these structural components. It is of great importance to detect corrosion under paint, particularly in its early stages. Millimeter wave nondestructive evaluation methods have shown great potential for detecting corrosion under paint and evaluating its properties. This paper presents and compares the results of using two distinct millimeter wave detection methods; namely a standard single probe and a newly developed differential probe for detecting corrosion under paint.

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An Estimative Current Mode Controller For Dc-Dc Converters Operating In Continuous Conduction Mode, Mehdi Ferdowsi Mar 2006

An Estimative Current Mode Controller For Dc-Dc Converters Operating In Continuous Conduction Mode, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

A new digital average-current-mode controller for converters operating in continuous conduction mode is introduced. The principal idea of the proposed control scheme is to estimate the required value of the duty ratio based on the dynamic of the converter using the measured samples of current and voltage signals. The proposed control scheme is stable for any value of the duty ratio without employing an external ramp. Furthermore, it is robust, accurate, and has a fast dynamic response.

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Direct Torque Control Of Five-Phase Induction Motor Using Space Vector Modulation With Harmonics Elimination And Optimal Switching Sequence, Shuai Lu, Keith Corzine Mar 2006

Direct Torque Control Of Five-Phase Induction Motor Using Space Vector Modulation With Harmonics Elimination And Optimal Switching Sequence, Shuai Lu, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper an effective direct torque control (DTC) for a 5-phase induction motor with sinusoidally distributed windings is developed. First by coordinate transformation, the converter/motor models are represented by two independent equivalent d-q circuit models; and the 5-phase VSI input are decoupled into the torque producing and non-torque producing harmonics sets. Then with the torque production component of the induction motor model, the space vector modulation (SVM) can be applied to the five-phase induction motor DTC control, resulting in considerable torque ripple reduction over the lookup table method. Based on the decoupled system model, the current distortion issue due …

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Fusion Of Microwave And Eddy Current Data For A Multi-Modal Approach In Evaluating Corrosion Under Paint And In Lap Joints, Kapil Gupta, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, R. Joe Stanley, Ajay Padwal, Matthew O'Keefe, Donald D. Palmer, J. Blackshire, Gary Steffes, N. Wood Mar 2006

Fusion Of Microwave And Eddy Current Data For A Multi-Modal Approach In Evaluating Corrosion Under Paint And In Lap Joints, Kapil Gupta, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, R. Joe Stanley, Ajay Padwal, Matthew O'Keefe, Donald D. Palmer, J. Blackshire, Gary Steffes, N. Wood

Electrical and Computer Engineering Faculty Research & Creative Works

Critical aircraft structures are susceptible to hidden corrosion. Find-it and fix-it approaches are inefficient as it relates to managing the problems associated with corrosion. More comprehensive corrosion information may be obtained using data fusion from several detection and evaluation methods. To this end, microwave, conventional and pulsed eddy current data from a multi-layer corroded panel, representing an aircraft lap joint, are fused and used as inputs to a structural analysis model to obtain a comprehensive snapshot of the corroded environment. This paper presents the data fusion algorithm and the structural analysis model along with a discussion of the results.

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Acoustic Detection And Classification Of Microchiroptera Using Machine Learning: Lessons Learned From Automatic Speech Recognition, Mark D. Skowronski, John G. Harris Mar 2006

Acoustic Detection And Classification Of Microchiroptera Using Machine Learning: Lessons Learned From Automatic Speech Recognition, Mark D. Skowronski, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

Current automatic acoustic detection and classification of microchiroptera utilize global features of individual calls (i.e., duration, bandwidth, frequency extrema), an approach that stems from expert knowledge of call sonograms. This approach parallels the acoustic phonetic paradigm of human automatic speech recognition (ASR), which relied on expert knowledge to account for variations in canonical linguistic units. ASR research eventually shifted from acoustic phonetics to machine learning, primarily because of the superior ability of machine learning to account for signal variation. To compare machine learning with conventional methods of detection and classification, nearly 3000 search-phase calls were hand labeled from recordings of …

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Neural Network-Based Output Feedback Controller For Lean Operation Of Spark Ignition Engines, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier, Jonathan B. Vance, Pingan He Jan 2006

Neural Network-Based Output Feedback Controller For Lean Operation Of Spark Ignition Engines, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier, Jonathan B. Vance, Pingan He

Electrical and Computer Engineering Faculty Research & Creative Works

Spark ignition (SI) engines running at very lean conditions demonstrate significant nonlinear behavior by exhibiting cycle-to-cycle dispersion of heat release even though such operation can significantly reduce NOx emissions and improve fuel efficiency by as much as 5-10%. A suite of neural network (NN) controller without and with reinforcement learning employing output feedback has shown ability to reduce the nonlinear cyclic dispersion observed under lean operating conditions. The neural network controllers consists of three NN: a) A NN observer to estimate the states of the engine such as total fuel and air; b) a second NN for generating virtual input; …

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Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy Jan 2006

Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The output limits of the power system stabilizer (PSS) can improve the system damping performance immediately following a large disturbance. Due to non-smooth nonlinearities from the saturation limits, these values cannot be determined by the conventional tuning methods based on linear analysis. Only ad hoc tuning procedures can been used. A feedforward neural network (FFNN) (with a structure of multilayer perceptron neural network) is applied to identify the dynamics of an objective function formed by the states, and thereafter to compute the gradients required in the nonlinear parameter optimization. Moreover, its derivative information is used to replace that obtained from …

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