Electrical and Computer Engineering Commons^™

Calderón Preconditioned Pmchwt Equation For Layered Medium Problems, Yongpin P. Chen, Lijun Jiang, Sheng Sun, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic scattering by dielectric objects in the presence of a layered medium is investigated by applying the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation combined with the layered medium Green's function. Due to the electric field integral equation (EFIE) operator involved, the spectrum of the PMCHWT equation is also undesired. When the surface is densely discretized, the condition of the resulting matrix is extremely bad. An effective Calderón preconditioner is developed in this paper to improve the convergence. Different from its free space counterpart, the Calderón identities for inhomogeneous medium need to be re-derived. It is shown from numerical examples that the convergence of …

Augmented Equivalence Principle Algorithm For Domain Decomposition Method For Low Frequency Scattering, Circuits, And Casimir Force Calculations, P. R. Atkins, Z. H. Ma, L. E. Sun, M. K. Li, L. (Lijun) J. Jiang, M. S. Tong, W. C. Chew

Electrical and Computer Engineering Faculty Research & Creative Works

A broadband integral-equation-based domain decomposition method (DDM) using augmented equivalence principle algorithm (A-EPA) is introduced for solving large scale electromagnetic scattering, circuits, and Casimir force problems. The root cause of the low frequency breakdown problem of EPA algorithm without augmentation technique is analyzed. Numerical examples validate the method for various applications in scattering, circuits, and Casimir force calculations.

The Contour Deformation Method For Calculating The High Frequency Scattered Fields By The Fock Current On The Surface Of The 3-D Convex Cylinder, Yu Mao Wu, Li (Lijun) Jun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, the Fock currents on the convex cylinders are comprehensively studied. The contour deformation method is invoked to calculate the highly oscillatory Fock currents. The computational process is frequency independent in workload. Then, quadratic phase approximation is proposed to efficiently solve the highly oscillatory scattered field. Numerical results for the high frequency scattered far fields on the convex cylinders are given to validate the efficiency of the proposed method. Furthermore, the contour deformation method for computing the Fock currents offers a clear high frequency wave physical picture.

Analysis Of Scattering By Pec Objects In Layered Medium With Calderón Preconditioner, Yongpin P. Chen, Min Meng, Sheng Sun, Lijun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic scattering by perfect electrically conducting (PEC) objects in a layered medium is studied in this paper. The layered medium Green's function is adopted as the kernel of the electric field integral equation (EFIE) so that the effects from the multilayered background can be accounted for automatically. However, the spectrum of the EFIE with this kernel, is unfortunately undesirable. This leads to slow convergence of the iterative solution. To improve the convergence, the Calderón identities are derived and leveraged to precondition the EFIE. By utilizing Buffa-Christiansen (BC) basis function in discretizing the preconditioning operator, the preconditioner can be made completely …

Differential Forms Inspired Finite Element Discretization For Waveguide Eigenvalue Problems, Qi I. Dai, Weng Cho Chew, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A differential forms inspired finite element based discretization scheme for waveguide eigenvalue problems is presented. Naïve discretization of the governing variational expression involving only transverse fields with edge elements renders the discretized eigen-equation unsolvable. Motivated by differential forms, in the proposed scheme, electric and magnetic fields are discretized with curl-conforming basis functions on the primal and dual grids, respectively. Meanwhile, magnetic flux density and electric displacement fields are discretized with divergence-conforming basis functions on the primal and dual grids, respectively. Matrices in the resultant eigen-equation is well-conditioned and easy to solve, which is validated by several numerical examples.

Uncertainty Quantification Of Em-Circuit Systems Using Stochastic Polynomial Chaos Method, Ping Li, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Uncertainties in realistic lumped and distributive circuit systems are of great importance to today's high yield manufacture demand. However, evaluating the stochastic effect in the time domain for the hybrid electromagnetics (EM)-circuit system was seldom done, especially when Monte Carlo is too expensive to be feasible. In this work, an adaptive hierarchical sparse grid collocation (ASGC) method is presented to quantify the impacts of stochastic inputs on hybrid electromagnetics (EM)-circuit or EM scattering systems. The ASGC method approximates the stochastic observables of interest using interpolation functions over series collocation points. Instead of employing a full-tensor product sense, the collocation points …

Effective Roughness Dielectric In A Pcb: Measurement And Full-Wave Simulation Verification, Tracey Vincent, Marina Koledintseva, Antonio Ciccomancini, Scott Hinaga

Electrical and Computer Engineering Faculty Research & Creative Works

Surface roughness topography of printed circuit boards (PCBs) needs to be included in SI simulations in order to accurately predict the insertion loss of the structure. An effective roughness dielectric (ERD) model can be used to substitute an inhomogeneous interface between copper foil and laminate dielectric in a PCB. Herein, this approach is tested for verification using 3D full-wave numerical simulations. These effective roughness dielectric layers with the appropriate complex permittivity are included in the modeling of strip line examples. The parameters of an ambient laminate dielectric free of conductor roughness effects in the strip line are determined using differential …

Epoxy Catalyzed Sol-Gel Method For Pinhole-Free Pyrite Fes2 Thin Films, S. Kment, H. Kmentova, A. Sarkar, R. J. Soukup, N. J. Ianno, D. Sekora, J. Olejnicek, P. Ksirova, J. Krysa, Z. Remes, Z. Hubicka

Department of Electrical and Computer Engineering: Faculty Publications

The uniform pinhole-free iron disulfide (FeS₂) pyrite thin films were fabricated. In the first step the FeO(OH)_x xerogel solution was synthetized by means of a novel epoxy catalyzed sol-gel method and next spin-coated onto various substrates to form the thin films. In the second step the xerogel coatings were annealed to yield hematite (α-Fe₂O₃) films, which were transformed into pyrite by chemical sulfurization. Among the main deposition parameters studied were the temperature of xerogel-hematite transformation and the optimal sulfurization temperature and duration. It has been observed that 15 min sulfurization at the temperature …

A Paper-Based Calorimetric Microfluidics Platform For Bio-Chemical Sensing, Benyamin Davaji, Chung Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

In this report, a paper-based micro-calorimetric biochemical detection method is presented. Calorimetric detection of biochemical reactions is demonstrated as an extension of current colorimetric and electrochemical detection mechanisms of paper-based biochemical analytical systems. Reaction and/or binding temperature of glucose/glucose oxidase, DNA/hydrogen peroxide, and biotin/streptavidin, are measured by the paper-based micro-calorimeter. Commercially available glucose calibration samples of 0.05, 0.15 and 0.3% wt/vol concentration are used for comparing the device performance with a commercially available glucose meter (electrochemical detection). The calorimetric glucose detection demonstrates a measurement error less than 2%. The calorimetric detection results of DNA concentrations from 0.9 to 7.3 mg/mL …

Applying Data Mining Tools To Archaeological "Big Data", Michael Polczynski, Mark Polczynski

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.

Application Of Information And Communication Technologies For Historical Research, Michael Polczynski, Mark Polczynski

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.

Emerging Role Of Photovoltaics For Sustainably Powering Underdeveloped, Emerging, And Developed Economies, Rajendra Singh, Amir A. Asif, Ganesh K. Venayagamoorthy, Akhlesh Lakhtakia, Mahmoud Abdelhamid, Githin F. Alapatt, David A. Ladner

Publications

With the advent of low-cost solar photovoltaic (PV) panels and our ability to generate, store, and use electrical energy locally without the need for long-range transmission, the world is about to witness transformational changes in electricity infrastructures. The use of DC electricity enhances systemwide efficiency. DC microgrids and nanogrids powered by solar PV systems and gigawatt batteries for electricity storage can sustainably power the needs of all human beings equitably and empower every individual. Ultralarge-scale manufacturing of PV systems and batteries, a vertically integrated business model, and a targeted monetary policy of quantitative easing can rapidly power all human activities.

Electric Bike Photovoltaic Charging Station (Pv-Cs): Experimental Design For Electrical Fault Investigations, Ayda Esfandyari, Kevin O'Farrell, Brian Norton, Sarah Mccormack

Conference Papers

Electric Vehicles (EV) have gained interest over the past decade. Accordingly, to support EV technology installation of charging stations are required. A Photovoltaic Charging Station (PV_CS) can generate clean electricity from the sun for charging electric bikes but as can be exposed to harsh weather conditions and faults, which can result in deviations of system characteristics from their normal operating conditions. Reliability of these charging stations is extremely important for supplying adequate charge to EVs, and therefore it must be maintained at all times. This paper presents a systematic approach to electrical reliability issues for PV_CS, by establishing an experimental …

Last Mile Asset Monitoring: Low Cost Rapid Deployment Asset Monitoring, Zdenek Zumr

Dissertations and Theses

Installation and utilization of residential distribution transformers has not changed substantially over a long period of time. Utilities typically size their transformers based on a formula that takes into account broadly what types and how many dwellings will be connected.

Most new residential dwellings feature 200 Amp service per household with an anticipated energy demand of under 20,000 kWh per year. Average electrical energy consumption varies from state to state but averages to 11,280 kWh per year. Energy demand is expected to fall into a typical residential load curve that shows increased demand early in the morning, then decreasing during …

A Generalized Proportionate Adaptive Algorithm Based On Convex Optimization, Jianming Liu, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

A general framework is proposed to derive proportionate adaptive algorithms for sparse system identification. The proposed algorithmic framework employs the convex optimization and covers many traditional proportionate algorithms. Meanwhile, based on this framework, some novel proportionate algorithms could be derived too. In the simulations, we compare the new derived proportionate algorithm with the traditional ones and demonstrate that it could provide faster convergence rate and tracking performance for both white and colored input in sparse system identification.

Near Optimal Event-Based Control Of Nonlinear Discrete Time Systems In Affine Form With Measured Input And Output Data, Avimanyu Sahoo, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an event-based near optimal control of uncertain nonlinear discrete time systems is presented by using input-output data and approximate dynamic programming (ADP). The nonlinear system dynamics in affine form are transformed into an input-output form. Then, three neural networks (NN) with event sampled input-output vector are used, namely, the identifier NN to relax the knowledge of the system dynamics, a critic NN to approximate the value function which is the solution to the Hamilton-Jacobi Bellman (HJB) equation, and an actor NN to approximate the optimal control policy, in an online manner without utilizing value or policy iterations. …

Electrical & Computer Engineering News, Georgia Southern University

Electrical & Computer Engineering: News & Publications (2014-2023)

• EE Department wins Sustainability Grant for Solar Vehicle Research

Finite Horizon Stochastic Optimal Control Of Nonlinear Two-Player Zero-Sum Games Under Communication Constraint, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the finite horizon stochastic optimal control of nonlinear two-player zero-sum games, referred to as Nonlinear Networked Control Systems (NNCS) two-player zero-sum game, between control and disturbance input players in the presence of unknown system dynamics and a communication network with delays and packet losses is addressed by using neuro dynamic programming (NDP). The overall objective being to find the optimal control input while maximizing the disturbance attenuation. First, a novel online neural network (NN) identifier is introduced to estimate the unknown control and disturbance coefficient matrices which are needed in the generation of optimal control input. Then, …

2014 Fall Engr333 Project Assignment, Matthew K. Heun

ENGR 333

The Fall 2014 ENGR333 project focused on net zero homes.

I asked the students “What would it take for a home in Grand Rapids to become net-zero?”

Customer

The customers for this project were several homeowners in the Grand Rapids area.

Optimization Algorithms For Inference And Classification Of Genetic Profiles From Undersampled Measurements, Belhassen Bayar

Theses and Dissertations

In this thesis, we tackle three different problems, all related to optimization techniques for inference and classification of genetic profiles. First, we extend the deterministic Non-negative Matrix Factorization (NMF) framework to the probabilistic case (PNMF). We apply the PNMF algorithm to cluster and classify DNA microarrays data. The proposed PNMF is shown to outperform the deterministic NMF and the sparse NMF algorithms in clustering stability and classification accuracy. Second, we propose SMURC: Small-sample MUltivariate Regression with Covariance estimation. Specifically, we consider a high dimension low sample-size multivariate regression problem that accounts for correlation of the response variables. We show that, …

Transmit Designs For The Mimo Broadcast Channel With Statistical Csi, Yongpeng Wu, Shi Jin, Xiqi Gao, Matthew R. Mckay, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

We investigate the multiple-input multiple-output broadcast channel with statistical channel state information available at the transmitter. The so-called linear assignment operation is employed, and necessary conditions are derived for the optimal transmit design under general fading conditions. Based on this, we introduce an iterative algorithm to maximize the linear assignment weighted sum-rate by applying a gradient descent method. To reduce complexity, we derive an upper bound of the linear assignment achievable rate of each receiver, from which a simplified closed-form expression for a near-optimal linear assignment matrix is derived. This reveals an interesting construction analogous to that of dirty-paper coding. …

Stochastic Optimal Design For Unknown Linear Discrete-Time System Zero-Sum Games In Input-Output Form Under Communication Constraints, Hao Xu, S. Jagannathan, F. L. Lewis

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, stochastic optimal strategy for unknown linear discrete-time system quadratic zero-sum games in input-output form with communication imperfections such as network-induced delays and packet losses, otherwise referred to as networked control system (NCS) zero-sum games, relating to the H∞ optimal control problem is solved in a forward-in-time manner. First, the linear discrete-time zero sum state space representation is transformed into a linear NCS in the state space form after incorporating random delays and packet losses and then into the input-output form. Subsequently, the stochastic optimal approach, referred to as adaptive dynamic programming (ADP), is introduced which estimates the …

Hybrid Silicon Mode-Locked Laser With Improved Rf Power By Impedance Matching, Bassem M. Tossoun

Master's Theses

The mode-locked laser diode (MLLD) finds a lot of use in applications such as ultra high-speed data processing and sampling, large-capacity optical fiber communications based on optical time-division multiplexing (OTDM) systems. Integrating mode-locked lasers on silicon makes way for highly integrated silicon based photonic communication devices. The mode-locked laser being used in this thesis was built with Hybrid Silicon technology. This technology, developed by UC Santa Barbara in 2006, introduced the idea of wafer bonding a crystalline III- V layer to a Silicon-on-insulator (SOI) substrate, making integrated lasers in silicon chips possible.

Furthermore, all mode-locked lasers produce phase noise, which …

Development Of Electroplated-Ni Structured Micromechanical Resonators For Rf Application, Mian Wei

USF Tampa Graduate Theses and Dissertations

On-chip vibrating MEMS resonators with high frequency-Q product on par with that of the off-chip quartz crystals have attracted lots of attention from both academia and industry for applications on sensing, signal processing, and wireless communication. Up to now, several approaches for monolithic integration of MEMS and transistors have been demonstrated. Vibrating micromechanical disk resonators which utilize electroplated nickel as the structural material along with either a solid-gap high-k dielectric capacitive transducer or a piezoelectric transducer have great potential to offer unprecedented performance and capability of seamless integration with integrated circuits.

Despite the frequency drift problems encountered in early attempts …

First Demonstration Of Ultra-Thin Sige-Channel Junctionless Accumulation-Mode (Jam) Bulk Finfets On Si Substrate With Pn Junction-Isolation Scheme, Donghyun Kim, Tae Kyun Kim, Young Gwang Yoon, Byeong Woon Hwang, Yang-Kyu Choi, Byung Jin Cho, Seok-Hee Lee

Electrical and Computer Engineering Faculty Research & Creative Works

A SiGe-channel junctionless-accumulation-mode (JAM) PMOS bulk FinFETs were successfully demonstrated on Si substrate with PN junction-isolation scheme for the first time. The JAM bulk FinFETs with fin width of 18 nm exhibits excellent subthreshold characteristics such as subthreshold swing of 64 mV/decade, drain-induced barrier lowering (DIBL) of 40 mV/V and high I_on/I_off current ratio ( > 1 x 10⁵). The change of substrate bias from 0 to 5 V leads to the threshold voltage shift of 53 mV by modulating the effective channel thickness. When compared to the Si-channel bulk FinFETs with fin width of 18 …

Simplified Parallel Interference Cancelation For Underdetermined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a low-complexity detection scheme is proposed for an underdetermined multiple-input-multiple-output (UD-MIMO) wireless communication system that employs N transmit antennas and M < N receive antennas. The proposed scheme combines a simplified parallel interference cancelation (S-PIC) with the block decision feedback equalization (BDFE) algorithm. To account for the extra (N - M)-dimension in the transmitted signal, the UD-MIMO system is partitioned into two subsystems: one with (N - M) transmit antennas and the other one with M transmit antennas. The interference from the first subsystem to the second one is canceled in parallel, and BDFE is performed over the second subsystem. Unlike conventional PIC methods that exhaustively search all the Q (N - M) sequences in the first subsystem, with Q being the constellation size, the proposed scheme explores only a small number of candidate sequences in the first subsystem; thus, it achieves significant complexity reduction. Two new candidate sequence selection methods are proposed. In the first iteration, the candidate sequences used for PIC are selected by exploring the statistical properties of the received signals. In the second iteration and beyond, the set containing the candidate sequences is constructed by utilizing the soft information generated from the previous iteration. The proposed scheme provides a balanced tradeoff between computational complexity and bit error rate (BER) performance.

Automated Synthetic Scene Generation, Ryan N. Givens

Theses and Dissertations

First principles, physics-based models help organizations developing new remote sensing instruments anticipate sensor performance by enabling the ability to create synthetic imagery for proposed sensor before a sensor is built. One of the largest challenges in modeling realistic synthetic imagery, however, is generating the spectrally attributed, three-dimensional scenes on which the models are based in a timely and affordable fashion. Additionally, manual and semi-automated approaches to synthetic scene construction which rely on spectral libraries may not adequately capture the spectral variability of real-world sites especially when the libraries consist of measurements made in other locations or in a lab. This …

Adaptive Control Of An Active Magnetic Bearing With External Disturbance, Lili Dong, Silu You

Electrical and Computer Engineering Faculty Publications

Adaptive back stepping control (ABC) is originally applied to a linearized model of an active magnetic bearing (AMB) system. Our control goal is to regulate the deviation of the magnetic bearing from its equilibrium position in the presence of an external disturbance and system uncertainties. Two types of ABC methods are developed on the AMB system. One is based on full state feedback, for which displacement, velocity, and current states are assumed available. The other one is adaptive observer based back stepping controller (AOBC) where only displacement output is measurable. An observer is designed for AOBC to estimate velocity and …

Generalized Approach Of Stator Shifting In Interior Permanent-Magnet Machines Equipped With Fractional-Slot Concentrated Windings, Patel B. Reddy, Kum-Kang Huh, Ayman M. El-Refaie

Electrical and Computer Engineering Faculty Research and Publications

Electrical drive systems, which include electrical machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the petroleum dependence of the ground transportation sector. To have significant effect, electric drive technologies must be economical in terms of cost, weight, and size while meeting performance and reliability expectations. Interior permanent magnet machines with fractional-slot concentrated windings have been shown to be good candidates for hybrid traction applications. One of the key challenges is the additional stator magnetomotive force sub- and superharmonic components that lead to higher losses in the rotor as well as saturation effects. …

Multi-Objective Tradeoffs In The Design Optimization Of A Brushless Permanent-Magnet Machine With Fractional-Slot Concentrated Windings, Peng Zhang, Gennadi Y. Sizov, Muyang Li, Dan M. Ionel, Nabeel Demerdash, Steven J. Stretz, Alan W. Yeadon

Electrical and Computer Engineering Faculty Research and Publications

In this paper, a robust parametric model of a brushless permanent magnet machine with fractional-slot concentrated windings, which was developed for automated design optimization is presented. A computationally efficient finite-element analysis method was employed to estimate the dq-axes inductances, the induced voltage and torque ripple waveforms, and losses of the machine. A method for minimum effort calculation of the torque angle corresponding to the maximum torque per ampere load condition was developed. A differential evolution algorithm was implemented for the global design optimization with two concurrent objectives of minimum losses and minimum material cost. An engineering decision process based on …