Engineering Commons^™

Application Of Composite Gyromagnetic Materials For Absorbing Radiation Produced By Microwave Oven, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin, V. P. Cheparin, Andrey A. Shinkov

Electrical and Computer Engineering Faculty Research & Creative Works

Composite gyromagnetic radioabsorbing material (RAM) on the basis of polycrystalline hexagonal ferrites is elaborated for the suppression of unwanted radiation produced by microwave ovens (MWO). Results of laboratory investigation of this material application in the MWO having a magnetron source of microwave radiation are represented.

Dynamic Re-Optimization Of A Fed-Batch Fermentor Using Heuristic Dynamic Programming, Donald C. Wunsch, M. S. Iyer

Electrical and Computer Engineering Faculty Research & Creative Works

Traditionally, fed-batch biochemical process optimization and control uses complicated theoretical off-line optimizers, with no online model adaptation or re-optimization. This study demonstrates the applicability, effectiveness, and economic potential of a simple phenomenological model for modeling, and an adaptive critic design, heuristic dynamic programming, for online re-optimization and control of an aerobic fed-batch fermentor. The results are compared with those obtained using a heuristic random optimizer

Excitation Of The High-Q-Factor Whispering Gallery Modes In The Hemispherical Dielectric Resonator With The Cylinder Shield, Sergey Kharkovsky, V. V. Kutuzov, A. E. Kogut

Electrical and Computer Engineering Faculty Research & Creative Works

A hollow metal cylinder with a semicircle in the base is used as the shield of a hemispherical dielectric resonator with whispering gallery (WG) modes. It is shown that the spectrum of the WG modes of this resonator is clearer than the spectrum of a similar resonator with a hemispherical shield. It is determined that the high-Q-factor WG modes are excited in the proposed resonator by the coupling slot on the mirror. Their fields are localized in the dielectric. The frequency dependence of the Q-factor value is measured. A good conformity of this experimental dependence with the analytic dependence is …

Fed-Batch Dynamic Optimization Using Generalized Dual Heuristic Programming, Donald C. Wunsch, M. S. Iyer

Electrical and Computer Engineering Faculty Research & Creative Works

Traditionally fed-batch biochemical process optimization and control uses complicated theoretical off-line optimizers, with no online model adaptation or re-optimization. This study demonstrates the applicability, effectiveness, and economic potential of a simple phenomenological model for modeling, and an adaptive critic design, generalized dual heuristic programming, for online re-optimization and control of an aerobic fed-batch fermentor. The results are compared with those obtained using a heuristic random optimizer

Climbing Fibre Purkinje Cell Twins Are Found, Donald C. Wunsch, Witali L. Dunin-Barkowski, S. N. Markin, L. N. Podladchikova

Electrical and Computer Engineering Faculty Research & Creative Works

At the IJCNN'93 in Nagoya we have pronounced a challenging goal: to get activity patterns of airs of Purkinje cells(PC), controlled with the same climbing fiber (CF), - a CF PC Twins problem Here, for the first time in cerebral studies, CF PC twins have been identified and studied. Several important features of the CF PC Twins activity are demonstrated: (1) High constancy of conduction time of impulses of cells of inferior olives to the targetted PCs, (2) a relatively high failure rate (0.05-0.18) of impulse propagation into terminal branches of CF, (3) a salient difference in complex Spikes(CS) - …

Microwave Oscillator With The Shielded Dielectric Resonator, Sergey Kharkovsky, A. E. Kogut, V. K. Komeenkov, V. I. Lutsenko

Electrical and Computer Engineering Faculty Research & Creative Works

A Gunn oscillator with partially shielded hemidisk quasioptical resonator is investigated experimentally in this paper. The investigations of the generation characteristics of oscillations by the semiconductor diode in this resonator are carried out for the different radial co-ordinates of the oscillator active element. The advantages of the investigated oscillator in comparison with the oscillator with an open dielectric resonator are shown

Neurocontrol Of Turbogenerators With Adaptive Critic Designs, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a neuro-controller for a turbogenerator using a novel technique based on adaptive critic designs (ACD). This adaptive critic design based neuro-controller augments/replaces the traditional automatic voltage regulator (AVR) and the turbine governor of the generator. Simulation results are presented to show that neural network controllers with the ACD have the potential to control turbogenerators when system conditions and configuration changes.

Nonuniformity Correction Of Infrared Image Sequences Using The Constant-Statistics Constraint, John G. Harris, Yu Ming Chiang

Electrical and Computer Engineering Faculty Research & Creative Works

Using clues from neurobiological adaptation, we have developed the constant-statistics (CS) algorithm for nonuniformity correction of IRFPA's and other imaging arrays. The CS model provides an efficient implementation that can also eliminate much of the ghosting artifact that plagues all scene-based nonuniformity correction (NUC) algorithms. The CS algorithm with deghosting is demonstrated on synthetic and real infrared (IR) sequences and shown to improve the overall accuracy of the correction procedure.

Use Of Transforms For Indexing In Audio Databases, S. R. Subramanya, Abdou Youssef, Bhagirath Narahari, Rahul Simha

Electrical and Computer Engineering Faculty Research & Creative Works

The phenomenal increases in the amounts of audio data being generated, processed and used in several computer applications have necessitated the development of audio database systems with newer features, such as content-based queries and similarity searches, to manage and use such data. Fast and accurate retrieval for content-based queries is crucial in order for such systems to be useful. Efficient content-based indexing and similarity searching schemes are keys to providing fast and relevant data retrieval. This paper studies and evaluates the different parameters involved in an indexing scheme which uses transforms (as used in signal processing) for generating the audio …

Reproduction Of Spectrum Envelope Of Microwave Wideband Noise And Detection A Narrowband Signal In It, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin

Electrical and Computer Engineering Faculty Research & Creative Works

A method of adequate visual microwave wide-band intense noise envelope reproduction in wide frequency range (several octaves), power parameters measurement and detection of a narrow-band signal with unknown frequency and power against a background of noise is presented. It is based on application of nonheterodyne gyromagnetic converter, operating in two regimes: resonance detection and cross-multiplication. Operation of the two-channel measurer of spectrum power density combining the mentioned functions is discussed

Speaker Identification Using A Combination Of Different Parameters As Feature Inputs To An Artificial Neural Network Classifier, Viresh Moonasar, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a technique using artificial neural networks (ANNs) for speaker identification that results in a better success rate compared to other techniques. The technique used in this paper uses both power spectral densities (PSDs) and linear prediction coefficients (LPCs) as feature inputs to a self organizing feature map to achieve a better identification performance. Results for speaker identification with different methods are presented and compared.

Differentiating Type Of Muscle Movement Via Ar Modeling And Neural Network Classification, Beki̇r Karlik

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this study is to classify electromyogram (EMG) signals for controlling multifunction proshetic devices. An artificial neural network (ANN) implementation was used for this purpose. Autoregressive (AR) parameters of $a_1, a_2, a_3, a_4$ and their signal power obtained from different arm muscle motions were applied to the input of ANN, which is a multilayer perceptron. At the output layer, for 5000 iterations, six movements were distinguished at a high accuracy of 97.6%.

Application Of The Fdtd Method For The Analysis Of Finite-Sized Phased Array Microstrip Antennas, Javier Gomez Tagle Rangel

Retrospective Theses and Dissertations

The Finite-Difference Time-Domain (FDTD) method has gained tremendous popularity in the past decade as a tool for solving Maxwell's equations. Phased Array Antennas find several applications including mobile communications ( cellular, personal communication systems and networks), satellite communications, global positioning system (GPS), aeronautical and radar systems. This dissertation describes the application of the FDTD method for calculating broadband characteristics of finite-sized phased array antennas consisting of microstrip elements fed with coaxial probes.

The characterization of such antennas is dependent upon the development of simulation tools that can accurately model general topologies including wires, dielectrics, conductors lumped elements and metallic strips. …

Réalisation De Couches Minces De Cualse² Par Recuit De Feuilllets Superposés Cu/Al/Se/Al…, Étude De Conditions De Dépôt, C.O. El Moctar, S. Marsillac, J. C. Bernede, A. Conan, K. Benchouk, A. Khelil

Electrical & Computer Engineering Faculty Publications

Thin layers of Cu/Al/Se/Al/Cu/Al/Se/…/Al/Se sequentially deposited have been annealed half an hour at 855 K. CuAlSe₂ thin films crystallized in the chalcopyrite structure are obtained. The films being contaminated by oxygen, the experimental deposition conditions of the aluminum layer have been improved in order to decrease the atomic concentration of oxygen below 5 at%. Such results can be obtained in vacuum of 10^-4 Pa, when the aluminum deposition rate is 1 nm/s and when the layer is immediately covered after deposition. Films obtained in such a way are nearly stoichiometric with lattice parameters in accordance with the expected …

Time-Resolved Reflection High-Energy Electron Diffraction Study Of The Ge(111)-C(2×8)-(1×1) Phase Transition, Xinglin Zeng, Bo Lin, Ibrahim El-Kholy, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The dynamics of the Ge(111)-c(2×8)-(1×1) phase transition is investigated by 100-ps time-resolved reflection high-energy electron diffraction. A laser pulse heats the surface while a synchronized electron pulse is used to obtain the surface diffraction pattern. Slow heating shows that the adatoms in Ge(111)-c(2×8) start to disorder at ∼510 K and are converted to a disordered adatom arrangement at 573 K. For heating with 100-ps laser pulses, the Ge(111)-c(2×8) reconstructed adatom arrangement starts to disorder at 584±16K, well above the onset temperature of ∼510 K for the disordering of Ge(111)-c(2×8) observed for slow …

Robust Controller Design For Time Delay Systems Using H-Infinity Techniques, Susan Carr, Aidan O'Dwyer

Conference papers

Using H-infinity control, the design problem is formulated in terms of user defined weighting polynomials on the process closed-loop sensitivity functions to achieve desired closed-loop performance and robust stability in the presence of process modelling error. In this paper stability conditions , in terms of the process sensitivity functions, are derived for processes containing a pure time delay for the following three design scenarios i) the time delay is neglected in the control design and is considered as part of the unmodelled process dynamics ii) A Pade approximation of the delay is included in the controller design and the effect …

Pi And Pid Controller Tuning Rules For Time Delay Processes: A Summary. Part 2: Pid Controller Tuning Rules, Aidan O'Dwyer

Conference papers

A summary of tuning rules for the PID control of single input, single output (SISO) processes with time delay, modeled in stable first order lag plus time delay (FOLPD) form, is provided in this part of the paper.

A Classification Of Techniques For The Compensation Of Time Delayed Processes. Part 2: Structurally Optimised Controllers, Aidan O'Dwyer, John Ringwood

Conference papers

Following on from Part 1, Part 2 of the paper considers the use of structurally optimised controllers to compensate time delayed processes.

Dynamic Modeling Of Pwm And Single-Switch Single-Stage Power Factor Correction Converters, Guangyong Zhu

Retrospective Theses and Dissertations

The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters operating in continuous conduction mode (CCM) and under small ripple conditions. Modeling of conductor losses under large ripple conditions has not been reported in the open literature, especially when the converter operates in discontinuous conduction mode (DCM). …

Physical And Technical Bases Of Using Ferromagnetic Resonance In Hexagonal Ferrites For Electromagnetic Compatibility Problems, Marina Koledintseva, Alexander A. Kitaytsev

Electrical and Computer Engineering Faculty Research & Creative Works

Frequency-selective measurement of microwave signal parameters based on application of gyromagnetic converters has proven advantageous for the research of microwave radiation over a wide spectrum (several octaves) in multisignal regime in microwave path and for the solution of a number of electromagnetic compatibility (EMC) problems. The measurement frequency band can be enlarged to millimeter-waves with application of monocrystal hexagonal ferrite resonators (HFR) having high internal magnetic fields. Millimeter-wave field interactions with the HFR having alternating resonance frequency are analyzed. This is useful for millimeter-wave signal modulation and demodulation. The analysis is based on the solution of magnetization vector motion equation …

In-Clip Search Algorithm For Content-Based Audio Retrieval, Punpiti Piamsa-Nga, Nikitas A. Alexandridis, Sanan Srakaew, George C. Blankenship, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

Researchers are currently more interested in searching for fragments that are similar to a query, than a total data item that is similar to a query; the search interest is for "contains", not "is". The paper presents an O(logn) algorithm, called the "generalized virtual node (GVN)" algorithm; the GVN algorithm is a search algorithm for data fragments that have similar contents to that of a query. An example of the use of the GVN algorithm is in the search of a database of audio recordings for a few measures of a melody. Each audio clip is transformed into characteristic features …

Doppler Measurements Using A Coherent Ultrawideband Random Noise Radar, Muhammad Dawood, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

The University of Nebraska has developed a random noise radar system which transmits an ultrawideband random noise waveform with a uniform power spectral density (PSD) in the 1-2 GHz frequency range. Simulation studies and controlled laboratory tests confirm the system's ability to preserve the instantaneous phase of the received signal [l, 2]. The potential of the system to characterize the Doppler shift of moving targets exhibiting varying linear and rotational velocities was clearly demonstrated [2]. This paper provides with the results of recent field experiments at a range of about 200 m which confirm the ability of the system to …

Complete Maps Of The Aspect Sensitivity Of Vhf Atmospheric Radar Echoes, R. M. Worthington, R. D. Palmer, S. Fukao

Department of Electrical and Computer Engineering: Faculty Publications

Using the MU radar at Shigaraki, Japan (34.85°N, 136.10°E), we measure the power distribution pattern of VHF radar echoes from the mid-troposphere. The large number of radar beam-pointing directions (320) allows the mapping of echo power from 0° to 40° from zenith, and also the dependence on azimuth, which has not been achieved before at VHF wavelengths. The results show how vertical shear of the horizontal wind is associated with a definite skewing of the VHF echo power distribution, for beam angles as far as 30° or more from zenith, so that aspect sensitivity cannot be assumed negligible at any …

Multiple Stochastic Learning Automata For Vehicle Path Control In An Automated Highway System, Cem Unsal, Pushkin Kachroo, John S. Bay

Electrical & Computer Engineering Faculty Research

This paper suggests an intelligent controller for an automated vehicle planning its own trajectory based on sensor and communication data. The intelligent controller is designed using the learning stochastic automata theory. Using the data received from on-board sensors, two automata (one for lateral actions, one for longitudinal actions) can learn the best possible action to avoid collisions. The system has the advantage of being able to work in unmodeled stochastic environments, unlike adaptive control methods or expert systems. Simulations for simultaneous lateral and longitudinal control of a vehicle provide encouraging results

Incident Management In Intelligent Transportation Systems, Kaan Ozbay, Pushkin Kachroo

Electrical & Computer Engineering Faculty Research

Since the conception of Intelligent Transportation Systems (ITS) in the 1980s, many transportation researchers have also worked on the development of incident management models and integrated systems for real-time operations. ITS created the required infrastructure for collecting, processing, and managing real-time traffic data that can be used to develop on-line incident management strategies. This book provides the reader with a broad picture of the overall incident management process in the context of ITS along with a quick review of the models and systems developed by numerous researchers worldwide. This book is a direct result of the long-term incident management research …

Feedback Control Theory For Dynamic Traffic Assignment, Pushkin Kachroo, Kaan Ozbay

Electrical & Computer Engineering Faculty Research

Traditionally, traffic assignment and traffic control in general have mostly been performed using optimisation techniques which do not lend themselves to real-time control. This volume presents feedback control techniques for performing traffic assignment in real-time, where traffic diversion control variables are instantaneous functions of sensed traffic variables. The authors outline the whole theory behind Intelligent Transportation Systems (ITS) which allows traffic variables to be sensed in real time and microprocessors to use the sensed traffic variable input to perform the traffic actuation tasks. They show h ow to design feedback controllers to perform dynamic traffic routing and assignment, and present …

Exclusive Disjunctions In Indefinite And Maybe Information In Relational Databases, Taflan İ. Gündem

Turkish Journal of Electrical Engineering and Computer Sciences

Incorporating indefinite information into databases has been studied extensively. In this paper, we propose a structure called an E-table to represent maybe information and inclusive and exclusive disjunctions. We define the type of redundancies in E-tables and show how to eliminate them. Also we present an extended relational algebra to operate on E-tables. In this paper we expand the concepts and operations defined by Lin and Sunderraman [1] in order to accommodate exclusive disjunctions in relational databases.

Grazing Reflection Of Gaussian Beams, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The reflectivities of most surfaces are higher for grazing or near-90-deg angles of incidence than for more perpendicular or near-zero-deg angles. Grazing-incidence configurations are especially important in the development of lasers and optical systems that operate in the far-ultraviolet and soft-x-ray regions of the spectrum, where transparent or highly reflecting media are almost unknown. Analytical solutions of the paraxial wave equation are obtained for the grazing reflection and complex interference effects that take place when a Gaussian beam interacts at shallow angles with a reflecting surface.

Constructive Induction Machines For Data Mining, Marek Perkowski, Stanislaw Grygiel, Qihong Chen, Dave Mattson

Electrical and Computer Engineering Faculty Publications and Presentations

"Learning Hardware" approach involves creating a computational network based on feedback from the environment (for instance, positive and negative examples from the trainer), and realizing this network in an array of Field Programmable Gate Arrays (FPGAs). Computational networks can be built based on incremental supervised learning (Neural Net training) or global construction (Decision Tree design). Here we advocate the approach to Learning Hardware based on Constructive Induction methods of Machine Learning (ML) using multivalued functions. This is contrasted with the Evolvable Hardware (EHW) approach in which learning/evolution is based on the genetic algorithm only. Various approaches to supervised inductive learning …

Trace: A Visual Software System To Explore Properties Of Reed-Muller Movement Functions, Marek Perkowski, Alan Mishchenko

Electrical and Computer Engineering Faculty Publications and Presentations

We present new experimental Windows 95/98/NT software for investigation of graph properties of boolean (in particular, Reed-Muller) logic with an equal number n of inputs and outputs (called movement functions). Realized at the input of an n-bit register, such functions create autonomous Finite State Machines (FSMs). TRACE software system allows the user to visualize State Transition Graphs (STGs) of the autonomous FSMs. Other features of TRACE help explore graph properties of function families. These families are produced by a generic function, differing from it only in the order of components, one operation, or one literal (this literal is complemented or …