Engineering Commons^™

System And Method For Generating Psuedo-Noise Sequences, Sina Balkir, Walter D. Leon Salas, Michael W. Hoffman, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is a method for generating psuedo-noise (PN) sequences utilizing a system comprised of a quantizer, and N directly quantized output/input map containing chaotic map cells, each in functional combination with combiner means and an m-bit shift register.

Adaptive Weighing Of Context Models For Lossless Data Compression, Matthew V. Mahoney

Electrical Engineering and Computer Science Faculty Publications

Until recently the state of the art in lossless data compression was prediction by partial match (PPM). A PPM model estimates the next-symbol probability distribution by combining statistics from the longest matching contiguous contexts in which each symbol value is found. We introduce a context mixing model which improves on PPM by allowing contexts which are arbitrary functions of the history. Each model independently estimates a probability and confidence that the next bit of data will be 0 or 1. Predictions are combined by weighted averaging. After a bit is arithmetic coded, the weights are adjusted along the cost gradient …

An Evolutionary Multi-Objective Crowding Algorithm (Emoca): Benchmark Test Function Results, Ramesh Rajagopalan, Chilukuri K. Mohan, Kishan G. Mehrotra, Pramod K. Varshney

Electrical Engineering and Computer Science - All Scholarship

A new evolutionary multi-objective crowding algorithm (EMOCA) is evaluated using nine benchmark multiobjective optimization problems, and shown to produce non-dominated solutions with significant diversity, outperforming state-of-the-art multi-objective evolutionary algorithms viz., Non-dominated Sorting Genetic Algorithm – II (NSGA-II), Strength Pareto Evolutionary algorithm II (SPEA-II) and Pareto Archived Evolution Strategy (PAES) on most of the test problems. The key new approach in EMOCA is to use a diversity-emphasizing probabilistic approach in determining whether an offspring individual is considered in the replacement selection phase, along with the use of a non-domination ranking scheme. This approach appears to provide a useful compromise between the …

Injection-Locking In Fabry-Perot Quantum-Well Lasers, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

No abstract provided.

College Of Engineering Senior Design Competition Fall 2005, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …

Structural Characteristics Of Carbon Nanofibers For On-Chip Interconnect Applications, Yusuke Ominami, Quoc Ngo, Alexander J. Austin, Hans Yoong, Cary Y. Yang, Alan M. Cassell, Brett A. Cruden, Jun Li, M. Meyyappan

Electrical and Computer Engineering

In this letter, we compare the structures of plasma-enhanced chemical vapor deposition of Ni-catalyzed and Pd-catalyzed carbon nanofibers (CNFs) synthesized for on-chip interconnect applications with scanning transmission electron microscopy (STEM). The Ni-catalyzed CNF has a conventional fiberlike structure and many graphitic layers that are almost parallel to the substrate at the CNF base. In contrast, the Pd-catalyzed CNF has a multiwall nanotubelike structure on the sidewall spanning the entire CNF. The microstructure observed in the Pd-catalyzed fibers at the CNF-metal interface has the potential to lower contact resistance significantly, as our electrical measurements using current-sensing atomic force microscopy indicate. A …

Performance Analysis Of Common Detectors For Shaped Offset Qpsk And Feher's Qpsk, Tom Nelson, Michael D. Rice, Erik Perrins

Faculty Publications

Sponsorship: US Air Force Grant FA9302-05-C-0001. A detector architecture capable of detecting both shaped offset quadrature phase shift keying (SOQPSK-TG) and Feher's quadrature phase shift keying (FQPSK-JR) is developed and analyzed. Both modulations are embodied as fully interoperable modulations in the Interrange Instrumentation Group (IRIG) standard IRIG-106. It is shown that the common detector achieves near optimal bit error rate performance without knowledge of which modulation is used by the transmitter. The detection techniques are based on a common trellis-coded modulation representation and a common continuous phase modulation (CPM) representation for these two modulations. In addition the common pulse amplitude …

Real-Time 3d Image Visualization System For Digital Video On A Single Chip, Nader I. Rafla

Electrical and Computer Engineering Faculty Publications and Presentations

Implementation of a real-time image visualization system on a reconfigurable chip (FPGA) is proposed. The system utilizes an innovative stereoscopic image capture, processing and visualization technique. Implementation is done as a two stage process. In the first stage, the stereo pair is captured using two image sensors. The captured images are then synchronized and sent to the second stage for fusion. A controller module is developed, designed, and placed on the FPGA for this purpose. The second stage is used for reconstruction and visualization of the 3D image. An innovative technique employing dual-processor architecture on the same single FPGA is …

Reliability Measurement Of Mass Storage System For Onboard Instrumentation, Minsu Choi, Nohpill Park, Vincenzo Piuri, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

Advances in spaceborne vehicular technology have made possible the long-life duration of the mission in harsh cosmic environments. Reliability and data integrity are the commonly emphasized requirements of spaceborne solid-state mass storage systems, because faults due to the harsh cosmic environments, such as extreme radiation, can be experienced throughout the mission. Acceptable dependability for these instruments has been achieved by using redundancy and repair. Reconfiguration (repair) of memory arrays using spare memory lines is the most common technique for reliability enhancement of memories with faults. Faulty cells in memory arrays are known to show spatial locality. This physical phenomenon is …

An Analysis Of Seawinds-Based Rain Retrieval In Severe Weather Events, David G. Long, Jeffrey R. Allen

Faculty Publications

The Ku-band SeaWinds scatterometer estimates near-surface ocean wind vectors by relating measured backscatter to a geophysical model function for the near-surface vector wind. The conventional wind retrieval algorithm does not explicitly account for SeaWinds' sensitivity to rain, resulting in rain-caused wind retrieval error. A new retrieval method, termed "simultaneous wind/rain retrieval," that estimates both wind and rain from rain-contaminated measurements has been previously proposed and validated with Tropical Rain Measuring Mission data. Here, the accuracy of rains retrieved by the new method is validated through comparison with the Next Generation Weather Radar (NEXRAD) in coastal storm events. The rains detected …

Atr-Ftir Spectroscopic Analysis Of Sorption Of Aqueous Analytes Into Polymer Coatings Used With Guided Sh-Saw Sensors, Yolanda K. Jones, Zhonghui Li, Michael M. Johnson, Fabien Josse, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Attenuated total internal reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used for the investigation of sorption of aqueous solutions of analytes into polymer coatings. A series of simple model polymers, such as poly(dimethylsiloxane), poly(epichlorhydrin), and poly(isobutylene), and films and analytes, such as aqueous solutions of ethylbenzene, xylenes, toluene, and nitrobenzene, were used to evaluate the use of ATR-FTIR spectroscopy as a screening tool for sensor development. The ratios of integrated infrared absorption bands provided a simple and efficient method for predicting trends in partition coefficients. Responses of polymer-coated guided shear horizontal surface acoustic wave (SH-SAW) sensor platforms to the series …

The Mixed-Form Fast Multipole Algorithm For Broadband Electromagnetic Simulations, L. (Lijun) J. Jiang, W. C. Chew

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

The General Variational Formulas For Capacitance Parameter Extraction, W. C. Chew, L. (Lijun) J. Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

To obtain second order accuracy using the first order data for the capacitance parameter extraction, a set of new generalized variational formulas are presented in this paper. They are complete since they are valid not only for self-capacitances, but also for mutual capacitances. A more general variational formula is derived to account for the asymmetrical elastance matrix case. By these novel formulas the computational accuracy can be significantly improved compared to the conventional direct capacitance extraction method. © 2005 IEEE.

Crosstalk Analysis By Fast Computational Algorithms, Z. G. Qian, J. Xiong, L. Sun, I. T. Chiang, W. C. Chew, L. (Lijun) J. Jiang, Y. H. Chu

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we will present the use of low frequency fast algorithms for crosstalk analysis. Some criss-cross line structures are studied and time domain signals are demonstrated to ascertain crosstalk effect. ©2005 IEEE.

A Mixed-Form Fast Multipole Algorithm, Li (Lijun) Jun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

The fast multipole algorithm manifests in two very different forms at low frequencies and at mid frequencies. Each can operate in their respective regimes, but are not tenable in the other regimes. The paper reports on a way to factorize the Green's function for fast algorithm using a mixed form. The low-frequency fast multipole algorithm (LF-FMA) will be used at low frequencies or the long-wavelength regime, and the multilevel fast multipole algorithm (MLFMA) will be used for the mid frequencies or the shorter-wavelength regime. For object modeling where both long-wavelength and wave physics are important, we propose a mixed-form fast …

A Novel Method For Determination Of Dielectric Properties Of Materials Using A Combined Embedded Modulated Scattering And Near-Field Microwave Techniques-Part Ii: Dielectric Property Recalculation, R. Zoughi, Dana Hughes

Electrical and Computer Engineering Faculty Research & Creative Works

The use of combined embedded modulated scattering technique and near-field microwave nondestructive testing techniques is investigated as a novel method for evaluating the dielectric properties of a material. The forward formulation for determining the reflection coefficient at the aperture of a waveguide radiating into a dielectric half-space in which a PIN diode-loaded dipole (i.e., modulated scattering technique probe) is embedded was presented in Part I of this paper. Here, in Part II, the recalculation of the dielectric properties, using the results of the forward model, is presented along with some associated experimental results.

A Novel Method For Determination Of Dielectric Properties Of Materials Using A Combined Embedded Modulated Scattering And Near-Field Microwave Techniques-Part I: Forward Model, Dana M. Hughes, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The use of combined embedded modulated scattering technique and near-field microwave nondestructive testing techniques is investigated as a novel method for evaluating the dielectric properties of a material. The forward formulation for determining the reflection coefficient at the aperture of a waveguide radiating into a dielectric half-space in which a PIN diode-loaded dipole (i.e., modulated scattering technique probe) is embedded is presented. This formulation is based upon calculating the near-field coupling between the waveguide and the dipole as a mutual impedance.

Modeling Microwave Emissions Of Erg Surfaces In The Sahara Desert, David G. Long, Haroon Stephen

Faculty Publications

Sand seas (ergs) of the Sahara are the most dynamic parts of the desert. Aeolian erosion, transportation, and deposition continue to reshape the surface of the ergs. The large-scale features (dunes) of these bedforms reflect the characteristics of the sand and the long-term wind. Radiometric emissions from the ergs have strong dependence on the surface geometry. We model the erg surface as composed of tilted rough facets. Each facet is characterized by a tilt distribution dependent upon the surface roughness of the facet. The radiometric temperature (Tb) of ergs is then the weighted sum of the Tb from all the …

Solving Low Frequency Electromagnetic Problems With Fast Solvers, W. C. Chew, L. (Lijun) J. Jiang, Y. H. Chu, Y. A. Liu, M. K. Li, Z. G. Qian, J. Xiong, L. Sun

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Modeling Of Capacitor Impedance In Switching Converters, Jonathan W. Kimball, Philip T. Krein, Kevin R. Cahill

Electrical and Computer Engineering Faculty Research & Creative Works

Switched capacitor (SC) converters are gaining acceptance as alternatives to traditional, inductor-based switching power converters. Proper design of SC converters requires an understanding of all loss sources and their impacts on circuit operation. In the present work, an equivalent resistance method is developed for analysis, and equivalent resistance formulae are presented for various modes of operation. Quasiresonant converters are explored and compared to standard SC converters. Comparisons to inductor-based switching power converters are made. A number of capacitor technologies are evaluated and compared for applications to both SC converters and inductor-based converters. The resulting model can be used to accurately …

Highly Efficient Fluorescence Detection In Picoliter Volume Liquid-Core Waveguides, Aaron R. Hawkins, John P. Barber, Dongliang Yin

Faculty Publications

We report loss improvement and fluorescence detection in integrated antiresonant reflecting optical waveguides with liquid cores. The minimum waveguide loss is reduced to 0.33/cm by compensating for thickness variations in the fabrication process. We demonstrate fluorescence detection from as few as 490 molecules in a 57 pl core using these optimized waveguides. We measure angular fluorescence collection factors as high as 15% per facet in good agreement with theory. This demonstrates the potential of integrated hollow-core waveguides as optical sensors for single-molecule spectroscopy.

Using Ultrasonic Atomization To Produce An Aerosol Of Micron-Scale Particles, Thomas D. Donnelly, J. Hogan '03, A. Mugler '04, M. Schubmehl '02, N. Schommer '04, Andrew J. Bernoff, S. Dasnurkar, T. Ditmire

All HMC Faculty Publications and Research

A device that uses ultrasonic atomization of a liquid to produce an aerosol of micron-scale droplets is described. This device represents a new approach to producing targets relevant to laser-driven fusion studies, and to rare studies of nonlinear optics in which wavelength-scale targets are irradiated. The device has also made possible tests of fluid dynamics models in a novel phase space. The distribution of droplet sizes produced by the device and the threshold power required for droplet production are shown to follow scaling laws predicted by fluid dynamics.

A Grasp For Unitary Space-Time Codes, Adam Panagos, Kurt Louis Kosbar

Electrical and Computer Engineering Faculty Research & Creative Works

Unitary space-time codes perform well at high signal-to-noise ratios on MIMO channels even when the propagation coefficients between transmitter and receiver are unknown. One method of constructing unitary space-time constellations uses a random search to find signal constellations that minimize the maximum pairwise correlation between transmitted signals. The work presented here uses a greedy randomized adaptive search procedure (GRASP) for finding good unitary space-time code constellations. Simulation results show that, on average, this technique finds codes with better correlation properties than the random search method. This new search procedure was also used to find signal constellations with better correlation properties …

Truncated Profile Hidden Markov Models, Jennifer A. Smith

Electrical and Computer Engineering Faculty Publications and Presentations

The profile hidden Markov model (HMM) is a powerful method for remote homolog database search. However, evaluating the score of each database sequence against a profile HMM is computationally demanding. The computation time required for score evaluation is proportional to the number of states in the profile HMM. This paper examines whether the number of states can be truncated without reducing the ability of the HMM to find proteins containing members of a protein domain family. A genetic algorithm (GA) is presented which finds a good truncation of the HMM states. The results of using truncation on searches of the …

Social Utility Functions-Part I: Theory, Wynn C. Stirling

Faculty Publications

The dominant approaches to utility-based multiagent decision theory rely on the premise of individual rationality-the doctrine that each individual is committed to achieving the best outcome for itself, regardless of the effect doing so has on others. This fundamentally asocial concept is the basis of conventional von Neumann-Morgenstern (vN-M) utilities but is inadequate to characterize truly cooperative artificial systems. Social utility functions differ from conventional vN-M utilities in that they are functions of multiple decision-maker preferences, rather than actions, and thus permit individuals to expand their spheres of interest beyond the self. A logical basis for coherent reasoning in multiagent …

Social Utility Functions-Part Ii: Applications, Wynn C. Stirling, Richard L. Frost

Faculty Publications

Social utilities account for agent preferences and, thus, can characterize complex interrelationships, such as cooperation, compromise, negotiation, and altruism, that can exist between agents. Satisficing game theory, which is based on social utilities, offers a framework within which to design sophisticated multiagent systems. Key features of this approach are: a) an N-agent system may be represented by a 2N-dimensional Bayesian network, called a praxeic network; b) the theory accommodates a notion of situational altruism (a willingness to defer to others in a controlled way if so doing would actually benefit others under the condition that others wish to take advantage …

H-Infinity Estimation For Fuzzy Membership Function Optimization, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Given a fuzzy logic system, how can we determine the membership functions that will result in the best performance? If we constrain the membership functions to a specific shape (e.g., triangles or trapezoids) then each membership function can be parameterized by a few variables and the membership optimization problem can be reduced to a parameter optimization problem. The parameter optimization problem can then be formulated as a nonlinear filtering problem. In this paper we solve the nonlinear filtering problem using H_∞ state estimation theory. However, the membership functions that result from this approach are not (in general) sum normal. …

Effects Of Ebg Reflection Phase Profiles On The Input Impedance And Bandwidth Of Ultrathin Directional Dipoles, M. Faisal Abedin, Mohammod Ali

Faculty Publications

A comprehensive study of the effects of the reflection phase profiles on dipole antennas is presented with the ultimate objective of designing ultrathin printed dipoles (as thin as one hundredth of the wavelength). Dipole driving-point impedance and bandwidth are studied as function of various electromagnetic bandgap (EBG) reflection phase profiles. It is demonstrated that although many different reflection phase profiles can be generated for a certain antenna height, it is the profile that satisfies a specific range of reflection phase angles that is required to achieve good antenna performance. Such optimum EBG phase profiles are generated for a number of …

Asynchronous Ds-Ss Cdma Random Spreading Code Correlation Statistics In The Presence Of Timing Error, David W. Matolak

Faculty Publications

We quantify the effect of timing tracking errors upon 2nd order correlation statistics of random binary spreading codes and, in so doing, fill a gap in the literature. Using a Gaussian model for timing tracking error, new expressions for autocorrelation statistics are derived. For crosscorrelations, we show that a zero mean Gaussian timing error has no effect upon 2nd order crosscorrelation statistics.

Measurement Sensitivity And Accuracy Verification For An Antenna Measurement System, Newlyn Hui, Aloysius Aragon Lubiano, Christopher R. Brito, Dean Arakaki

Electrical Engineering

An antenna measurement system was developed to complement a new rectangular anechoic chamber (20’L x 10’W x 9’7”H) that has been established at California Polytechnic State University (Cal Poly) through donations and financial support from industry and Cal Poly departments and programs. Software algorithms were written to provide four data acquisition methods: continual sweep and step mode for both single and multiple frequencies. Log magnitude and phase information for an antenna under test is captured over a user-specified angular position range and the antenna's radiation pattern is obtained after post processing. Pattern comparisons against theoretical predictions are performed. Finally an …