Engineering Commons^™

An Impact Of Layer Stack-Up On Emi, S. Radu, Theodore M. Zeeff, Joe Nuebel, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation of a server shows the heatsink of the CPU module as a primary component of the EMI coupling path. In order to identify the specific noise source and coupling path to the heatsink, a series of experiments were defined to provide support for one source and eliminate others. Based on experiments with two different versions of the CPU module, a stack-up related design guideline is proposed: a ground layer should be the first entire plane (as opposed to V_cc) on the active component side of the board. If there are known IC sources that switch significant currents …

Considerations For Magnetic-Field Coupling Resulting In Radiated Emi, David M. Hockanson, James L. Drewniak, Richard E. Dubroff, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Parasitic inductance in printed circuit board geometries can worsen the EMI performance and signal integrity of high-speed digital designs. Partial-inductance theory is a powerful tool for analyzing inductance issues in signal integrity. However, partial inductances may not adequately model magnetic flux coupling to EMI antennas because the EMI antennas are typically open loops. Therefore, partial inductances may not always accurately predict radiated EMI from noise sources, unless used in a full-wave analysis such as PEEC. Partial inductances can be used, however, to estimate branch inductances, which can be used to predict EMI. This paper presents a method for decomposing loop …

Time History Extrapolation For Fdtd Modeling Of Shielding Enclosure Designs And Emi Antenna Geometries, Xiao Luo, Min Li, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The GPOF (generalized pencil-of-function) method was used to extrapolate the time response from FDTD simulations of EMI problems by approximating the time history as a sum of complex exponentials. This method can significantly shorten the FDTD program execution time. However, various difficulties can arise from parameterization during data-processing. The GPOF is applied to, and studied for, two relevant EMI problems, enclosure design and EMI antenna modeling. The merits of GPOF in modeling shielding enclosures and EMI antennas is evaluated through several examples

Modeling Multilayered Pcb Power-Bus Designs Using An Mpie Based Circuit Extraction Technique, Hao Shi, Jun Fan, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

A circuit extraction tool (CEMPIE) has been developed based on the mixed-potential integral equation (MPIE) using a quasi-static approximation. A power-bus in a multi-layered PCB consisting of a pair of dedicated ground and power planes is studied using this tool. The distributed behavior of a power-bus is represented by a collection of passive circuit elements, which is valid up to several gigahertz. The decoupling performance of a power-bus due to its layer spacing and the dielectric constant is evaluated for simple test geometries. The impact of the relative distance between the noise source and the potential receiver is also studied. …

A Feasibility Study Of On-Line Excitation System Parameter Estimation, Eric Ludwig, K. Shah, Kelvin T. Erickson, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper details a feasibility study of estimating excitation system parameters during online operation using time-domain system identification. This study concentrates on identifying the appropriate exciter model, developing an input signal that would provide a proper level of perturbation such that the dynamics of the system can be captured, analyzing the effects of both systematic and random noise, developing algorithms to perform the parameter estimation, testing and validating the obtained system parameters. This study established a strong basis for estimating the system parameters during online operation.

Global Positioning System (Gps) Receiver Design For Multipaths Mitigation, El-Sayed Abdel-Salam Gadallah

Theses and Dissertations

Multipath effects are a source of error degrading the accuracy of DGPS signal processing. The statistical models of multipath are determined by user location and, in addition are time varying. There is no unified statistical model for the multipath signal. Therefore the solution of the multipath problem using statistical models is difficult. This research introduces a new estimator that can detect the presence of multipath, can determine the unknown number of multipath components and can estimate multipath parameters in the GPS receiver (time delay and attenuation coefficients). Furthermore the multipath signal parameters are estimated at any instant of observation. The …

Photographic Studies Of Laser-Induced Bubble Formation In Absorbing Liquids And On Submerged Targets: Implications For Drug Delivery With Microsecond Laser Pulses, Hanqun Shangguan, Lee W. Casperson, Dennis L. Paisley, Scott A. Prahl

Electrical and Computer Engineering Faculty Publications and Presentations

Pulsed laser ablation of blood clots in a fluid-filled blood vessel is accompanied by an explosive evaporation process. The resulting vapor bubble rapidly expands and collapses to disrupt the thrombus (blood clot). The hydrodynamic pressures following the bubble expansion and collapse can also be used as a driving force to deliver clot-dissolving agents into thrombus for enhancement of laser thrombolysis. Thus, the laser-induced bubble formation plays an important role in the thrombus removal process. We investigate the effects of boundary configurations and materials on bubble formation with time-resolved flash photography and high-speed photography. Potential applications in drug delivery using microsecond …

Wavelet-Based Noise Reduction In Multispectral Imagery, Abdullah A. Basuhail, Samuel Peter Kozaitis

Electrical Engineering and Computer Science Faculty Publications

We used a 3-D wavelet-based denoising method to reduce the noise from multispectral imagery. In our approach, we compared denoising of different bands of a multispectral image using a 2-D denoising technique, by which the wavelet coefficients corresponding to each band were denoised independent of each band, and a 3-D denoising technique by which the wavelet coefficients were denoised by involving all bands in thresholding the wavelet coefficients. Due to the high correlation of the multispectral imagery data along the wavelength axis, the noise can be easily reduced by applying the wavelet transform along the wavelength direction. Our results showed …

Binary Multilevel Convolutional Codes With Unequal Error Protection Capabilities, Robert H. Morelos-Zaragoza, Hideki Imai

Faculty Publications

Binary multilevel convolutional codes (CCs) with unequal error protection (UEP) capabilities are studied. These codes belong to the class of generalized concatenated (GC) codes. Binary CCs are used as outer codes. Binary linear block codes of short length, and selected subcodes in their two-way subcode partition chain, are used as inner codes. Multistage decodings are presented that use Viterbi decoders operating on trellises with similar structure to that of the constituent binary CCs. Simulation results of example binary two-level CC's are also reported.

The Optimized Electrostatic Motor, Christopher Lee Rambin

Doctoral Dissertations

The most common means of electrically activated actuation is the electromagnetic motor. All electromagnetic motors have a low output to weight ratio and low energy efficiency. The motor's weight is due to the coils and magnets used to generate propulsion. The energy loss is mainly the result of Joule heating that is inherent with any current driven device. An electrostatic motor offers the potential of significantly less weight and higher energy efficiency. This lower weight characteristic is due to the epoxide material used to construct the major components of its propulsion unit. Greater efficiency results from the reduced Joule heating …

Fuzzy Logic Applied To System Control To Enhance Commercial Appliance Performance, Glenn Moffett

Doctoral Dissertations

The purpose of this research is to determine the usefulness of fuzzy logic and fuzzy control when applied to a commercial appliance. Fuzzy logic is a structured, model-free estimator that approximates a function through linguistic input/output associations. Fuzzy rule-based systems apply these methods to solve many types of "real-world" problems, especially where a system is difficult to model, is controlled by a human operator or expert, or where ambiguity or vagueness is common.

This dissertation presents fuzzy sets, fuzzy systems, and fuzzy control, with an example conveying the use of fuzzy control of a consumer product and an overview of …

Experimental Investigations Of Wavelength And Angular Errors In Holographic Gratings With Non-Bragg-Matched Read Beams, Monish Ranjan Chatterjee, Vivek Ray

Electrical and Computer Engineering Faculty Publications

Perfect Bragg matching is generally desirable for accurate optical interconnections with holographic gratings. In reality, however, gratings may be illuminated by READ beams with non-Bragg-matched angles, or wavelengths, or both. In such cases, the scattered beams are generally misdirected, and may suffer loss of efficiency and possibly more serious errors such as crosstalk noise or missed connections. A conventional wave-vector triad method of analyzing the scattered beam errors leads readily to near-Bragg estimates of the output angular misalignment. However, the READ wave-vector triads appear to indicate a possible wavelength shift in the output beam even with a Bragg-matched READ wavelength, …

In Situ Infrared And Visible-Light Ellipsometric Investigations Of Boron Nitride Thin Films At Elevated Temperatures, E. Franke, Mathias Schubert, J.-D. Hecht, H. Neumann, T. E. Tiwald, Daniel W. Thompson, H. Yao, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

In situ infrared (IR) spectroscopy and visible-light (VIS) spectroscopic ellipsometry over the spectral range from 700 to 2000 cm^-1 and 1.5–3.5 eV, respectively, were used to investigate the optical behavior of boron nitride (BN) thin films at temperatures from room temperature (RT) to 600 °C. The polycrystalline hexagonal (h) and mixed-phase h- and cubic (c)-BN thin films were deposited by magnetron sputtering on [001] silicon. We observe a reversible moisture incorporation process in as-grown h-BN samples. When stored in normal ambient, the h-BN thin films absorb water into thin-film micropores. When annealed in ultrahigh vacuum or a …

High Pressure Radio-Frequency Microhollow Cathode Discharges, Anja Annett Muller

Electrical & Computer Engineering Theses & Dissertations

A new field of microhollow cathode discharges is represented by the RF microhollow cathode discharge. So far, the behavior and related physical processes of the RF microhollow cathode discharge are not well investigated.

RF microhollow discharges in air at high pressures were investigated under different experimental conditions. The geometry was changed by reducing the cathode hole diameter and the dielectric spacer thickness. By adding a noble gas to air, the influence of additive gases was explored. Additionally, the parallel operation of RF microhollow discharges was investigated.

It was shown that stable RF microhollow cathode discharges could only be sustained up …

Reactions Of Oxygen And Nitric Oxide In A Microhollow Electrode Discharge, Joseph L. Desormeaux Jr.

Electrical & Computer Engineering Theses & Dissertations

Microhollow electrode discharges have been developed and researched in the Physical Electronics Research Institute Laboratories. This discharge typically operates in direct current mode. Microhollow electrode discharges are non-thermal discharges that produce electrons with energies greater than 10 electron volts. Passing gas mixtures through non-equilibrium discharges invokes excitation or dissociation of gas molecules.

The scope of my research was to study the effect of the discharge on the chemistry of two gases, oxygen and nitric oxide in nitrogen mixture. Initial experiments were performed in an effort to produce ozone near atmospheric pressure. This seemed possible since the discharge has a high-energy …

An Injection Modelocked Titanium-Sapphire Laser, James C. Hovater

Electrical & Computer Engineering Theses & Dissertations

I have investigated the possibility of using an injection modelocked Ti-sapphire laser as a illumination source for GaAs photocathodes. A commercial Ti-sapphire laser was modified to accept a seed pulse from a gain-switched diode laser. Modelocked operation was obtained through gain modulation within the Ti-sapphire crystal as a result of injection seeding with a modelocked pulse train from a gain-switched diode laser. The Ti-sapphire laser essentially becomes a pulse amplifier for the diode laser. Unlike conventional modelocked lasers, the pulse repetition rate of this laser can be discretely varied by setting the seed laser repetition rate equal to multiples of …

Coupled Electrodynamic-Monte Carlo Simulations Of Nanoscale Gaas Terahertz Optical Mixers, Jiang Li

Electrical & Computer Engineering Theses & Dissertations

The concept of mixing or heterodyning has traditionally been used for microwaves and for radio frequency communications. However, the concept can easily be extended into the optical frequency regime. By doing so, the photomixing process can serve as a very versatile tool for both the generation of ultrahigh frequency (terahertz) and the detection of weak optical signals.

The aim of this thesis is to perform a theoretical study of the photomixing process inside GaAs devices as the non-linear elements. A coupled approach which combines the Monte Carlo simulation scheme for the carrier transport, with Maxwell's equation for the electrodynamics, has …

Effect Of Pulsed Electric Fields On Aquatic Nuisance Species, Amr Abou-Ghazala

Electrical & Computer Engineering Theses & Dissertations

Clinical and theoretical evidence indicate that electric fields have biological effects ranging from recoverable disturbance to mortality induction depending on the field parameters and time of exposure. In this thesis, the effect of electrical field in pulsed form on aquatic nuisance species is investigated. Pulse parameters in terms of amplitude, width, shape, and repetition rate that stimulate the species to desirable levels are to be defined. Applying the electrical pulses with appropriate parameters to stun aquatic nuisance species entering marine cooling systems will prevent it from attaching to pipe walls. The use of electrical fields to seek efficient, environmentally friendly, …

Microhollow Cathode Discharge Excimer Lamps, Ahmed El-Habachi

Electrical & Computer Engineering Theses & Dissertations

Microhollow cathode discharges are non-thermal discharges of such small sizes that thermalization of the electrons is prevented. By reducing the diameter of the cathode opening in these discharge geometries to values on the order of 100 $\mu$m we were able to operate discharges in argon and xenon in a direct current mode up to atmospheric pressure. The large concentration of high electrons, in combination with high pressures favors three body processes such as excimer formation. This was confirmed by experiments in xenon and argon where emission of excimer radiation at 172 nm and 130 nm, respectively, was observed when the …

The Cluster Multipole Algorithm For Far-Field Computations, Rakesh R. Patel

Electrical & Computer Engineering Theses & Dissertations

Computer simulations of N-body systems are beneficial to study the overall behavior of a number of physical systems in fields such as astrophysics, molecular dynamics, and computational fluid dynamics. A new approach for computer simulations of N-body systems is proposed in this research. The new algorithm is called the Cluster Multipole Algorithm (CMA). The goals of the new algorithm are to improve the applicability to non-point sources and to provide more control on the accuracy over current algorithms. The algorithm is targeted to applications that do not require rebuilding the data structure about the system every time step due to …

Quantum Theory Of The Linewidth Of A Laser With A Saturable Absorber: Phase Diffusion, Michael Sokol

Electrical Engineering and Computer Science Faculty Publications

A quantum theory of the spectral width of a laser with a saturable absorber is presented. We perform a density matrix calculation yielding the off-diagonal element ρ n,n+1(t) which is proportional to the average value of the electric field associated with the laser field having a large photon number n. The general linewidth theory is applied to any general laser which has saturable absorber features for a portion of the building of the laser field. We have found that the saturable absorber action contribution to the linewidth of such a laser can be substantial. © 1998 Society of Photo-Optical Instrumentation …

Electrical Characteristics And Parallel Operation Of Microhollow Cathode Discharges, Wenhui Shi

Electrical & Computer Engineering Theses & Dissertations

This thesis describes the electrical properties of microhollow cathode discharges with argon as filling gas. The appearance and current-voltage characteristics of microhollow cathode discharges have been recorded. Three kinds of discharge modes (predischarge, hollow cathode discharge and abnormal discharge) have been observed. The range of operation of the hollow cathode discharge has been found to be 0.5 < pD & 5 Torr cm in argon. By reducing the hole diameter to 100 pm, we were able to operate the discharge to atmospheric pressure in a dc mode. The possibility of dc parallel operation of microhollow cathode discharges was explored. Parallel operation could be obtained without individual ballast for discharges with a positive I-V slope greater than 10 V/mA over a voltage range of more than 5 % of the sustaining voltage. For parallel operation outside the range the ballasting is required. This model was explored by using a segmented anode model. The result of the simple calculation coincides well with the experiment result, where a semi-insulator silicon was used as distributed ballast.

Trends Of Microcomputer Technology In Developing Countries, With More Focus On Tanzanian Experiences: Achievements And Problems, Satoki Mahenge

Tanzania Journal of Engineering and Technology (TJET)

Trends of microcomputer technology in developing countries, including Tanzanian. is like a 'mixed bag' of achievement and problems. Although rhe technology has been available for many years in developed world, developing countries are responding to it differently due to differences in political and economic policies. Some countries have acrimonious policies on the technology, some not. There are countries which utilize fully the technology in work places and others are still at dilemma on the importation of the technology due to what is 'claimed to be a weak economy in the presence Of many other pressing needs'. Other countries seem to …

Optimization Of Network Signal Timing, Xiao-Hua Yu, Allen R. Stubberud

Electrical Engineering

A typical urban traffic network is a complicated large-scale stochastic system which consists of many interconnected signalized traffic intersections. This paper develops a decentralized real-time adaptive control strategy for the traffic networks based on Markov decision theory. Computer simulation results of this new approach on a five intersection traffic network indicate significant improvement over the traditional fully actuated control algorithm.

Representations, Approximations, And Algorithms For Mathematical Speech Processing, Laura R. Suzuki

Theses and Dissertations

Representing speech signals such that specific characteristics of speech are included is essential in many Air Force and DoD signal processing applications. A mathematical construct called a frame is presented which captures the important time-varying characteristic of speech. Roughly speaking, frames generalize the idea of an orthogonal basis in a Hilbert space, Specific spaces applicable to speech are L₂(R) and the Hardy spaces H_p(D) for p> 1 where D is the unit disk in the complex plane. Results are given for representations in the Hardy spaces involving Carleson's inequalities (and its extensions), …

Near-Field Source Localization Using Music With Polynomial Rooting, Hsien-Sen Hung, Shun-Hsyung Chang, Chien-Hsing Wu

Journal of Marine Science and Technology–Taiwan

In this paper, the bearing, elevation, and range estimation of near-field narrow-band sources from data observed across an array of sensors is considered. For high-resolution source localization, the multiple signal classification (MUSIC) algorithm is modified and extended to its 3-D version by accounting for spherical curvature and spreading factor in the array manifold. However, the simultaneous estimation of bearing, elevation, and range from 3-D MUSIC spectrum requires exhaustive multidimensional search. As to alleviate computational load, an alternative algorithm is proposed. The proposed algorithm involves search in the range domain combined with polynomial rooting, which replaces the search in the azimuth-elevation …

Routing And Broadcasting Algorithms For The Root-Folded Petersen Etworks, Ming-Bo Lin, Grene-Eu Jan

Journal of Marine Science and Technology–Taiwan

Petersen networks have been proposed as the alternatives for interconnecting highly parallel computers. The main advantages of Petersen networks are: regular topology, high scalability, and smaller diameters. In this paper, we propose a new node naming scheme for Petersen networks. Based on this scheme, two Petersen graph related networks, called root-folded Petersen network in type-I and type-II, are constructed. Furthermore, both O(1ogio N) routing and broadcasting algorithms for the proposed networks are developed, where N is the number of nodes.

A Unified Approach For The Robust Spr Property Of A Parametric Uncertainty System, Chih-Yung Cheng, Chao-Fong Chang

Journal of Marine Science and Technology–Taiwan

In this paper, we adopt a unified approach based on the concept of value set to analyze the robust strict positive real (SPR) property of uncertain systems with interval, affine linear or multilinear uncertainty structures.

System And Method For Performing Optical Code Division Multiple Access Communication Using Bipolar Codes, James F. Young, Benhaam Aazhnag, Lim Nguyen

Department of Electrical and Computer Engineering: Faculty Publications

An optical encoding and decoding system which performs code-division multiple access (CDMA) communication in the incoherent, or direct detection, optical domain using bipolar +1/-1 codes. The present invention uses code modu lation and detection principles that permit all-optical imple mentation of the bipolar. +1/-1. code and correlation detec tion that have been developed for the radio frequency (RF) systems. This is possible in spite of the non-negative, or unipolar, +1/0, nature of the incoherent optical system that only detects and processes the signal intensity. The unipolar optical system of the present invention is equivalent to the bipolar RF system in …

Simulation Of The Hybrid Fuzzy-Boolean Finite State Machine (Hfb-Fsm), Hamed Shakouri

Masters Theses

Several models of fuzzy finite-state automata have been proposed in the literature. One model which benefits from the existing algorithms for designing Boolean finite-state machines, has been proposed by J. L. Grantner [8]. This model, which is called Hybrid Fuzzy-Boolean Finite State Machine (HFB-FSM), along with its algorithmic design procedure, can be used for implementing dynamic linguistic systems [7,8,13]. In this thesis we have developed a simulation program for the HFB-FSM model using C++ programming language. In order to simulate a HFB-FSM model, the user provides the information defining the system's behavior. Based on the algorithm proposed in [8], the …