Engineering Commons^™

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

Design Of Airflow Aperture Arrays In Shielding Enclosures, Min Li, S. Radu, J. Neubel, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

EMI through perforation patterns for airflow in shielding enclosures resulting from coupling of interior sources is investigated numerically with FDTD simulations and experimentally. The FDTD simulations are compared with measurements on perforation patterns. A simple empirical design approach for the relation between aperture size, the number of apertures and shielding effectiveness is extracted. A double perforation pattern structure is proposed for perforation pattern designs where a high percentage of open area is required. Frequencies where the enclosure will support cavity modes are of primary concern.

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 …

Architectural Optimization Of Digital Libraries, Aileen O. Biser

Computer Science Theses & Dissertations

This work investigates performance and scaling issues relevant to large scale distributed digital libraries. Presently, performance and scaling studies focus on specific implementations of production or prototype digital libraries. Although useful information is gained to aid these designers and other researchers with insights to performance and scaling issues, the broader issues relevant to very large scale distributed libraries are not addressed. Specifically, no current studies look at the extreme or worst case possibilities in digital library implementations. A survey of digital library research issues is presented. Scaling and performance issues are mentioned frequently in the digital library literature but are …

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 …

Bridge Deck Deicing, Sherif A. Yehia, Christopher Y. Tuan

Civil Engineering Faculty Proceedings & Presentations

Concrete bridge decks are prone to ice accumulation. The use of road salts and chemicals for deicing is cost effective but causes damage to concrete and corrosion of reinforcing steel in concrete bridge decks. This problem is a major concern to transportation officials and public works due to rapid degradation of existing concrete pavements and bridge decks. The use of insulation materials for ice control and electric or thermal heating for deicing have been attempted and met limited success. Conductive concrete may be defined as a cementitious composite, which contains a certain amount of electronically conductive components to attain stable …

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.

Nonlinear Optimal Control Design Of A Missile Autopilot, Tim Mclain, Randal W. Beard

Faculty Publications

The application of a new nonlinear optimal control strategy to the design of missile autopilots is presented. The control approach described and demonstrated here is based upon the numerical solution of the Hamilton-Jacobi-Bellman equation by Successive Galerkin Approximation. Using this approach, feedback controllers are computed by an iterative application of a numerical Galerkin-type PDE solver. Simulation results demonstrating the application of this approach to the design of a missile autopilot are presented.

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 …

Scalar Quark Searches In E+E- Collisions At √S = 181 - 184 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Searches for scalar top, scalar bottom and degenerate scalar quarks have been performed with data collected with the ALEPH detector at LEP. The data sample consists of 57 pb−1 taken at s = 181–184 GeV. No evidence for scalar top, scalar bottom or degenerate scalar quarks was found in the channels t̃→cχ, t̃→bℓν̃, b̃→bχ, and q̃→qχ. From the channel t̃→cχ a limit of 74 GeV/c2has been set on the scalar top quark mass, independent of the mixing angle. This limit assumes a mass difference between the t̃ and the χ in the range 10–40 GeV/c2. From the channel t̃→bℓν̃ the …

Evaluation Of Personal Communications Dual-Antenna Handset Diversity Performance, Michael A. Jensen, Joseph S. Colburn, Yahya Rahmat-Samii, Gregory J. Pottie

Faculty Publications

In personal wireless communications systems, multipath propagation has a significant effect on system design and performance. Signal strength fading caused by destructive interference between multiple replicas of the signal of interest arriving at the receiver over different paths often is the limiting factor in system range/fidelity. Antenna diversity is one technique that can be used to help overcome multipath fading. This paper presents a description of experiments, data processing, and results used to evaluate the diversity performance of three candidate dual-antenna handset configurations: two side-mounted planar-inverted F antennas (PIFAs), a back-mounted PIFA with a top-mounted helix, a top-mounted PIFA, and …

Influence Of Ash Deposit Chemistry And Structure On Physical And Transport Properties, Larry Lin Baxter 8507091

Faculty Publications

Boiler ash deposits generated during combustion of coal, biomass, black liquor, and energetic materials affect both the net plant efficiency and operating strategy of essentially all boilers. Such deposits decrease convective and radiative heat exchange with boiler heat transfer surfaces. In many cases, even a small amount of ash on a surface decreases local heat transfer rates by factors of three or more. Apart from their impact on heat transfer, ash deposits in boilers represent potential operational problems and boiler maintenance issues, including plugging, tube wastage (erosion and corrosion), and structural damage. This report relates the chemistry and microstructural properties …

Discovering Methodologies For Integrated Product Design, Cirrus Shakeri, David C. Brown, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

The current methodologies for multi-disciplinary product design are based on compromising between different disciplines rather than integrating them. These methodologies do not use a systematic and holistic approach to the problem of multi-disciplinary design and thus are piecemeal rather than comprehensive. This paper presents a new approach to producing design methodologies for integration of the different disciplines in the design process. A multi-agent system has been developed that designs a 2-DOF robot arm by incorporating five proposed strategies for integration between disciplines. Design methodologies are extracted by tracking the system and generalizing the traces that are produced. The results show …

40th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 40th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 25 - August 1, 1998.

Nebraska Tractor Test Museum Committee Minutes July 21, 1998, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

State Fair Planning Camp Creek Threshers First Newsletter

Maximally Disjoint Solutions Of The Set Covering Problem, David J. Rader, Peter L. Hammer

Mathematical Sciences Technical Reports (MSTR)

This paper is concerned with finding two solutions of a set covering problem that have a minimum number of variables in common. We show that this problem is NP­ complete, even in the case where we are only interested in completely disjoint solutions. We describe three heuristic methods based on the standard greedy algorithm for set covering problems. Two of these algorithms find the solutions sequentially, while the third finds them simultaneously. A local search method for reducing the overlap of the two given solutions is then described. This method involves the solution of a reduced set covering problem. Finally, …

Electronic Package Comprising A Substrate And A Semiconductor Device Bonded Thereto, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A composition containing a polymeric matrix and a conductive filler component is provided. The conductive filler component comprises conductive particles and a polymer selected from the group consisting of substituted and unsubstituted polyanilines, substituted and unsubstituted polyparaphenylenevinylenes, substituted and unsubstituted polythiophenes, substituted and unsubstituted polyazines, substituted and unsubstituted polyparaphenylenes, substituted and unsubstituted polyfuranes, substituted and unsubstituted polypyrroles, substituted and unsubstituted polyselenophene, substituted and unsubstituted poly-p-phenylene sulfides and substituted and unsubstituted polyacetylenes, and mixtures thereof, and copolymers thereof. The compositions of the present invention are useful as adhesives for interconnecting a semiconductor chip to a substrate

Electronic Package Comprising A Substrate And A Semiconductor Device Bonded Thereto, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A composition containing a polymeric matrix and a conductive filler component is provided. The conductive filler component comprises conductive particles and a polymer selected from the group consisting of substituted and unsubstituted polyanilines, substituted and unsubstituted polyparaphenylenevinylenes, substituted and unsubstituted polythiophenes, substituted and unsubstituted polyazines, substituted and unsubstituted polyparaphenylenes, substituted and unsubstituted polyfuranes, substituted and unsubstituted polypyrroles, substituted and unsubstituted polyselenophene, substituted and unsubstituted poly-p-phenylene sulfides and substituted and unsubstituted polyacetylenes, and mixtures thereof, and copolymers thereof. The compositions of the present invention are useful as adhesives for interconnecting a semiconductor chip to a substrate

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 …

Acuta Enews July 1998, Vol.27, No. 5

ACUTA Newsletters

In This Issue

ACUTA Board of Directors '98-'99

Board Report

Is This an ACUTA Anniversary for You?

New Fiber Optics

DC at a Glance

Connecting Off-Campus Housing to the Network

Positions Available

Welcome New Members

Beyond Interval Systems: What Is Feasible And What Is Algorithmically Solvable?, Vladik Kreinovich

Departmental Technical Reports (CS)

In many real-life applications of interval computations, the desired quantities appear (in a good approximation to reality) as a solution to a system of interval linear equations. It is known that such systems are difficult to solve (NP-hard) but still algorithmically solvable. If instead of the (approximate) interval linear systems, we consider more realistic (and more general) formulations, will the corresponding problems still be algorithmically solvable? We consider three natural generalizations of interval linear systems: to conditions which are more general than linear systems, to multi-intervals instead of intervals, and to dynamics (differential and difference equations) instead of statics (linear …

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.

Drip/Micro Irrigation Survey For Delano-Earlimart Irrigation District, Charles M. Burt

BioResource and Agricultural Engineering

Delano-Earlimart ID (DEID) has kept informal statistics on the use of drip and micro-irrigation (drip/micro) within its boundaries for several years. These statistics showed that there has been only a slight increase in the acreage of these systems over the past 10 years. Because the rate and extent of conversion to drip/micro may influence the type of future water delivery service needed from DEID, DEID management is interested in knowing more about farmer perceptions regarding these newer irrigation methods.

DEID obtained a grant from USBR Mid-Pacific region to examine perceptions of its farmers regarding future conversions to drip and micro-irrigation. …

Kolmogorov Complexity Justifies Software Engineering Heuristics, Ann Q. Gates, Vladik Kreinovich, Luc Longpre

Departmental Technical Reports (CS)

The "clean bill of health" produced by such a technique does not guarantee that the program is actually correct. In this paper, we show that several heuristic techniques for software testing that have been developed in software engineering can be rigorously justified. In this justification, we use Kolmogorov complexity to formalize the terms "simple" and "random" that these techniques use. The successful formalization of simple heuristics is a good indication that Kolmogorov complexity may be useful in formalizing more complicated heuristics as well.

Development And Realization Of A Single-Mode Optical Fiber Ferrule Mold Insert With Twelve Channels, Hsiharng William Yang

Doctoral Dissertations

A manufacturing process for an optical fiber ferrule mold insert with twelve channels has been established. This research project presents mask design, mask fabrication, deep X-ray lithography exposure, resist developing, nickel electroforming, as well as surface finishing to attain the final result. Deep X-ray mask fabrication methods are explored, including mechanically machined masks, micro-EDM masks, and E-beam written masks. The exposures to pattern resists and electroforming to fabricate nickel molds up to 500 $\mu$m thickness are reported in this study. Nickel structures for the optical fiber ferrule insert with twelve channels made by electroforming are the final products. A practical …

Fatigue: Investigation Of A Human Factor For Regional Airline Pilots, Doug Mikkelsen

Master's Theses - Daytona Beach

This study analyzed the causes of regional airline pilot fatigue and the impact on pilot performance. An instrument was developed and refined through a field study validation by a panel of experts. The final instrument was distributed to three groups of regional airline pilots. The data supported the literature review, which revealed many causes of pilot fatigue, including flight crew schedules that are not compatible with human limitations; Federal Aviation Regulations (FARs) that have not evolved with the advancement of aircraft performance and the public demand for 24 hour availability of flights; and poor personal habits. An analysis of the …

Field Performance Report On 1219 Mm Hdpe Pipe On Us 127, Owen County, L. John Fleckenstein, David L. Allen

Kentucky Transportation Center Research Report

This report documents the installation and performance of a 1219 mm (48-inch) corrugated smooth lined polyethylene (HDPE) pipe installed during reconstruction of US 127 in Owen County. The pipe installed was manufactured by Advanced Drainage Systems, Inc., and is designated as ADS N-12. pipe.

The culvert was installed in a 6-meter (20-foot) high embankment. The culvert pipe was installed in two sequences. The first half of the structure was bedded and backfilled with No. 8 stone and the second half of the structure was bedded and backfilled with pipe sand (crushed limestone).

The pipe appears to be performing well. The …

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 …

Quality Of Service Semantics For Multimedia Database Systems, Jonathan Walpole, Charles Krasic, Ling Liu, David Maier, Calton Pu, Dylan Mcnamee, David Steere

Computer Science Faculty Publications and Presentations

Quality of service (QoS) support has been a hot research topic in multimedia databases, and multimedia systems in general, for the past several years. However, there remains little consensus on how QoS support should be provided. At the resource-management level, systems designers are still debating the suitability of reservation- based versus adaptive QoS management. The design of higher system layers is less clearly understood, and the specification of QoS requirements in domain-specific terms is still an open research topic. To address these issues, we propose a QoS model for multimedia databases. The model covers the specification of user-level QoS preferences …