Electrical and Computer Engineering Commons^™

Alan Turing Se Fraye Un Chemin Jusqu'À La Place De L'Ordinateur, Christof Teuscher

Electrical and Computer Engineering Faculty Publications and Presentations

A brief statement on the significance, impact and future developments related to the work of computer pioneer Alan Turing, in conjunction with Turing Day, held to commemorate his 90th birthday.

*The article is in French

Atomic Force Microscopy Of Dna Self-Assembled Nanostructures For Device Applications, Hieu Bui, Craig Onodera, Bernard Yurke, Elton Graugnard, Wan Kuang, Jeunghoon Lee, William B. Knowlton, William L. Hughes

Electrical and Computer Engineering Faculty Publications and Presentations

DNA nanotechnology, which relies on Watson-Crick hybridization, is a versatile selfassembly process whereby a variety of complex nanostructures can be fabricated with sublithographic features.[1] Adopting this technology, 1012 identical devices can be synthesized to have hundreds of components with 1nm resolution. Example nanostructures include: 1) DNA motifs [2], 2) two-dimensional DNA crystals [3], and DNA origami [4]. Currently, this technology is being adopted towards electronic, optical, and opto-electronic devices.[5]

Gain Guiding In Large-Core Bragg Fibers, Xianyu Ao, Tsing-Hua Her, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

We theoretically analyze gain guiding in large-core Bragg fibers, to be used for large-mode-area laser amplifiers with single-transverse-mode operation. The signal is gain-guided in a low-index core, whereas the pump is guided by the photonic bandgap of the Bragg cladding to achieve good confinement. The high-index layers in the Bragg cladding are half-wave thick at the signal wavelength in order to eliminate Bragg reflection, reducing the Bragg fiber effectively to a step-index fiber for gain guiding.

Computer-Aided Assessment Of Diagnostic Images For Epidemiological Research, Alison G. Abraham, Donald D. Duncan, Stephen J. Gange, Sheila West

Electrical and Computer Engineering Faculty Publications and Presentations

Background: Diagnostic images are often assessed for clinical outcomes using subjective methods, which are limited by the skill of the reviewer. Computer-aided diagnosis (CAD) algorithms that assist reviewers in their decisions concerning outcomes have been developed to increase sensitivity and specificity in the clinical setting. However, these systems have not been well utilized in research settings to improve the measurement of clinical endpoints. Reductions in bias through their use could have important implications for etiologic research. Methods: Using the example of cortical cataract detection, we developed an algorithm for assisting a reviewer in evaluating digital images for the presence and …

Effects Of Sea-Surface Conditions On Passive Fathometry And Bottom Characterization, Steven L. Means, Martin Siderius

Electrical and Computer Engineering Faculty Publications and Presentations

Recently, a method has been developed that exploits the correlation properties of the ocean’s ambient noise to measure water depth (a passive fathometer) and seabed layering [M. Sideriuset al., J. Acoust. Soc. Am.120, 1315–1323 (2006)]. This processing is based on the cross-correlation between the surface noise and the echo return from the seabed. To quantitatively study the dependency between processing and environmental factors such as wind speed, measurements were made using a fixed hydrophone array while simultaneously characterizing the environment. The measurements were made in 2006 in the shallow waters (25m)approximately 75km off the coast of Savannah, GA. …

New Metric Describes Edge Noise In Bilevel Images, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

A new approach enables quantitative and qualitative characterization of varying edge noise even if the additive noise level is constant.

Evolution Of Chemical Structure During Silver Photodiffusion Into Chalcogenide Glass Thin Films, A. Kovalskiy, H. Jain, Maria Mitkova

Electrical and Computer Engineering Faculty Publications and Presentations

The change of chemical structure resulting after X–ray and photo-induced silver diffusion into chalcogenide glass (ChG) thin films is monitored by high resolution X-ray photoelectron spectroscopy (XPS). As₄₀S₆₀ and Ge₃₀Se₇₀ thin films, which are based on pyramids and tetrahedral structural units, are investigated as model materials. Survey, core level (As 3d, S 2p, Ge 3d, Ge 2p, Se 3d, Ag 3d_5/2, O 1s, C 1s) and valence band spectra have been recorded and analyzed. Reference point for the …

Effects Of Gaussian Fields On The Stability Of Inhomogeneously Broadened Lasers, Pitak Chenkosol, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Under some conditions, spontaneous coherent pulsations are known to occur in the output beams of inhomogeneously broadened laser oscillators. These lasers typically operate with a Gaussian transverse field distribution, while the corresponding theoretical models assume a uniform-plane-wave field. The effects of a Gaussian field on the stability criteria of single-mode inhomogeneously broadened ring laser oscillators are considered in this study. It is found that in comparison to a plane wave a Gaussian field variation still permits low-threshold spontaneous pulsations but reduces the parameter space over which these pulsations can be observed.

A K-Delta-1-Sigma Modulator For Wideband Analog To Digital Conversion, Vishal Saxena, Kaijun Li, Geng Zheng, R. Jacob Baker

Electrical and Computer Engineering Faculty Publications and Presentations

As CMOS technology shrinks, the transistor speed K-quantizing paths and can achieve significantly higher conversion bandwidths when compared to the traditional deltasigma ADCs. The 8-path KD1S modulator achieves an SNR of 58 dB (or 9.4-bits resolution) when clocked at 100 MHz for a conversion bandwidth of 6.25 MHz and an effective sampling rate equal to 800 MHz. The KD1S modulator has been fabricated in a 500 nm CMOS process and the experimental results are reported. Deficiencies in the first test chip performance are discussed along with their alleviation to achieve theoretical performance.

Compact Optical Curvature Sensor With A Flexible Microdisk Laser On A Polymer Substrate, Wan Kuang, M. H. Shih, K. S. Hsu, Y. C. Yang, Y. C. Wang, S. K. Tsai, Y. C. Liu, Z. C. Chang, M. C. Wu

Electrical and Computer Engineering Faculty Publications and Presentations

In this paper, a chip-scale compact optical curvature sensor was demonstrated. It consists of a low threshold InGaAsP microdisk laser on a flexible polydimethylsiloxane polymer substrate. The curvature dependence of lasing wavelength was characterized by bending the cavity at different bending radii. The measurements showed that the lasing wavelength decreases monotonously with an increasing bending curvature. A good agreement between experiment and three-dimensional finite-difference time-domain simulation was also obtained. The sensitivity of the compact device to the bending curvature is -23.7 nm/mm form the experiment.

Indirect Compensation Techniques For Three-Stage Cmos Op-Amps, Vishal Saxena, R. Jacob Baker

Electrical and Computer Engineering Faculty Publications and Presentations

As CMOS technology continues to evolve, the supply voltages are decreasing while at the same time the transistor threshold voltages are remaining relatively constant. Making matters worse, the inherent gain available from the nano-CMOS transistors is dropping. Traditional techniques for achieving high-gain by vertically stacking (i.e. cascoding) transistors becomes less useful in nano-scale CMOS processes. Horizontal cascading (multi-stage) must be used in order to realize high-gain op-amps in low supply voltage processes. This paper discusses new design techniques for the realization of three-stage op-amps. The proposed and experimentally verified op-amps, fabricated in 500 nm CMOS, typically exhibit 30 MHz unity-gain …

Stability Criteria For Spontaneously Pulsing Gas Lasers, Pitak Chenkosol, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Low-threshold spontaneous pulsations are known to occur in the output beams of certain high-gain gas lasers, and good agreement between the experimental observations and numerical models has been achieved. There have also been several analytical studies of threshold criteria for spontaneously pulsing lasers. However, the analytical studies are mostly not applicable to the lasers in which the pulsations have been observed. Stability criteria for high-gain gas lasers are derived in this study, and these criteria are compared with a previously modeled gas laser instability.

Chip-Scale Nanophotonic Chemical And Biological Sensors Using Cmos Process, Lincoln Bollschweiler, Alex English, R. Jacob Baker, Wan Kuang, Zi-Chang Chang, Ming-Hsiung Shih, William Knowlton

Electrical and Computer Engineering Faculty Publications and Presentations

A monolithic integrated chip-scale surface plasmon resonance (SPR) sensor is demonstrated. The device consists of a pn photodiode covered with a periodic modified thin metal film whose lattice constant is on the order of the wavelength of light. The device performs real-time measurement of resonant wavelengths of enhanced optical transmission due to surface plasmon resonance, which are influenced by the presence of chemical or biological materials at the device’s surface.

On-Chip Intrinsic Evolution Methodology For Sequential Logic Circuit Design, Fan Xiong, Nader Rafla

Electrical and Computer Engineering Faculty Publications and Presentations

This paper focuses on the application of Virtual Reconfigurable Circuit (VRC) design methodology and intrinsic evolution for the design of small sequential circuits and their implementation on a single programmable chip with an embedded hardcore processor. The evolutionary algorithm is developed in software that runs on the embedded processor. Fitness function is calculated using hardware architecture and is used to guide the evolution process. This new method is applied to the development of a 3-bit sequence detector and the evolved architecture is implemented on a Xilinx™ Virtex-II pro device. Simulations were run on the evolved architecture and on the same …

Gain Saturation In Gain-Guided Slab Waveguides With Large-Index Antiguiding, Tsing-Hua Her, Xianyu Ao, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

We investigate numerically and analytically the effects of gain saturation on the propagation of the fundamental mode in a gain-guided index-antiguided slab waveguide. The propagating mode adapts to gain saturation by becoming less confined, while at the same time its peak intensity increases more slowly. At steady state, both the mode shape and the power remain constant.

Camera-Based Ballot Counter, George Nagy, Bryan Clifford, Andrew Berg, Glenn Saunders, Dan Lopresti, Elisa Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

Portable ballot counters using camera technology and manual paper feed are potentially more reliable and less expensive than scanner based systems. We show that the spatial sampling rate, geometric linearity, point spread function, and photometric transfer function of off-the-shelf consumer cameras are acceptable for ballot imaging. However, scanner illumination is much more uniform than can be economically accomplished for variable size ballots. Therefore flat-field compensation must be designed into the image processing software. We illustrate the mechanical design of a prototype camera based ballot reader based on our comparative observations.

Style-Based Ballot Mark Recognition, Pingping Xiu, Daniel Lopresti, Henry Baird, George Nagy, Elisa Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

The push toward voting via hand-marked paper ballots has focused attention on the limitations of current optical scan systems. Discrepancies between human and machine interpretations of ballot markings can lead to a loss of trust in the election process. In this paper, a style-based approach to ballot recognition is proposed in which marks are recognized collectively rather than in isolation. The consistency of a voter’s style is leveraged to improve the overall accuracy of the system. We compare style-based recognition to various kinds of singlet classifiers and show that it outperforms them by a substantial margin

Rna Search With Decision Trees And Partial Covariance Models, Jennifer A. Smith

Electrical and Computer Engineering Faculty Publications and Presentations

The use of partial covariance models to search for RNA family members in genomic sequence databases is explored. The partial models are formed from contiguous subranges of the overall RNA family multiple alignment columns. A binary decision-tree framework is presented for choosing the order to apply the partial models and the score thresholds on which to make the decisions. The decision trees are chosen to minimize computation time subject to the constraint that all of the training sequences are passed to the full covariance model for final evaluation. Computational intelligence methods are suggested to select the decision tree since the …

Monte Carlo Green's Function Formalism For The Propagation Of Partially Coherent Light, Scott A. Prahl, David G. Fischer, Donald D. Duncan

Electrical and Computer Engineering Faculty Publications and Presentations

We present a Monte Carlo-derived Green's function for the propagation of partially spatially coherent fields. This Green's function, which is derived by sampling Huygens-Fresnel wavelets, can be used to propagate fields through an optical system and to compute first- and second-order field statistics directly. The concept is illustrated for a cylindrical f/1 imaging system. A Gaussian copula is used to synthesize realizations of a Gaussian Schell-model field in the pupil plane. Physical optics and Monte Carlo predictions are made for the first- and second-order statistics of the field in the vicinity of the focal plane for a variety of source …

A Wireless Sensor Data Fusion Framework For Contaminant Detection, Joshua Kiepert, Sin Ming Loo

Electrical and Computer Engineering Faculty Publications and Presentations

In recent years, much research has been done on wireless sensor networks and sensor data fusion, however there has been limited work regarding implementation of real systems that are capable of providing a highly connected sensor network for data logging and data fusion applications. This paper describes the design and implementation of a wireless, portable, and reconfigurable sensor network framework. This sensor node design has proven to be effective for monitoring environmental conditions of aircraft cabins and is well suited to environmental monitoring and detection of contaminants in large areas when utilizing sensor data fusion features.

Dc-Ac Cascaded H-Bridge Multilevel Boost Inverter With No Inductors For Electric/Hybrid Electric Vehicle Applications, Zhong Du, Burak Ozpineci, Leon M. Tolbert, John N. Chiasson

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications implemented without the use of inductors. Currently available power inverter systems for HEVs use a dc–dc boost converter to boost the battery voltage for a traditional three-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. A cascaded H-bridge multilevel boost inverter design for EV and HEV applications implemented without the use of inductors is proposed in this paper. Traditionally, each H-bridge needs a dc power supply. The …

Extended Superposed Quantum State Initialization Using Disjoint Prime Implicants, David Rosenbaum, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

Extended Superposed Quantum State Initialization Using Disjoint Prime Implicants (ESQUID) is a new algorithm for generating quantum arrays for the purpose of initializing a desired quantum superposition. The quantum arrays generated by this algorithm almost always use fewer gates than other algorithms and in the worst case use the same number of gates. These improvements are achieved by allowing certain parts of the quantum superposition that cannot be initialized directly by the algorithm to be initialized using special circuits. This allows more terms in the quantum superposition to be initialized at the same time which decreases the number of gates …

The Dsp Of Money, Thad B. Welch, Cameron H. G. Wright, Michael G. Morrow

Electrical and Computer Engineering Faculty Publications and Presentations

This paper discusses a simple framework that can be used to connect a significant number of the tools and techniques developed in a first course in either discrete-time signals and systems or digital signal processing. While this framework is not revolutionary, it allows for the rapid placement of new material into the course’s context. Additionally, a simple model of an unstable financial system allows for a rapid introduction and overview of the course while observably increasing student interest and motivation. In these challenging economic times, it is somewhat reassuring to know that some unstable financial accounts are actually a good …

Mark Detection From Scanned Ballots, Elisa H. Barney Smith, George Nagy, Daniel Lopresti

Electrical and Computer Engineering Faculty Publications and Presentations

Analyzing paper-based election ballots requires finding all marks added to the base ballot. The position, size, shape, rotation and shade of these marks are not known a priori. Scanned ballot images have additional differences from the base ballot due to scanner noise. Different image processing techniques are evaluated to see under what conditions they are able to detect what sorts of marks. Basing mark detection on the difference of raw images was found to be much more sensitive to the mark darkness. Converting the raw images to foreground and background and then removing the form produced better results.

Incits W1.1 Standards For Perceptual Evaluation Of Text And Line Quality, Edul N. Dalal, Elisa H. Barney Smith, Frans Gaykema, Allan Haley, Kerry Kirk, Don Kozak, Mark Robb, Tim Qian, Ming-Kai Tse

Electrical and Computer Engineering Faculty Publications and Presentations

INCITS W1.1 is a project chartered to develop an appearance-based image quality standard. This paper summarizes the work to date of the W1.1 Text and Line Quality ad hoc team, and describes the progress made in developing a Text Quality test pattern and an analysis procedure based on experience with previous perceptual rating experiments.

Lyapunov Stability Of An Open-Loop Induction Machine, Ahmed Oteafy, John Chiasson

Electrical and Computer Engineering Faculty Publications and Presentations

The induction machine is widely utilized in the industry and exists in a plethora of applications. Although it is characterized by its inherent stability over a wide range of operating conditions, this characterization is based on steadystate arguments. This work develops a rigorous approach to the open-loop stability of the induction machine. In particular, a condition for the global asymptotic stability of the induction machine in the sense of Lyapunov is presented. These conditions are met if the machine is lightly loaded. Hence, meeting these conditions guarantees that the motor will reach (or return to) the desired equilibrium point regardless …

High Dynamic Performance Programmed Pwm Control Of A Multilevel Inverter With Capacitor Dc Sources, John Chiasson, Zhong Du, Burak Özpineci, Leon M. Tolbert

Electrical and Computer Engineering Faculty Publications and Presentations

A cascade multilevel inverter consisting of a standard 3-leg inverter supplied by a DC source and three full H-bridges each supplied by a capacitor is considered for use as a motor drive. The capacitor H-bridges can only supply reactive voltage to the motor while the standard three leg inverter can supply both reactive and active voltage. A switching control algorithm is presented that shows this inverter topology can be used as an AC drive achieving considerable performance advantages (e.g., higher motor speed) compared to using a standard 3-leg inverter while at the same time regulating the capacitor voltages. The converter …

Edge Noise In Document Images, Craig Mcgillivary, Chris Hale, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

A degradation model that describes many image degradations produced by desktop scanning is used to study the edge noise that is present in bilevel document images. The standard deviation of the additive noise does not adequately describe the noise present after the image is converted to a bilevel image. A measure of noise called Noise Spread is developed which describes the edge noise and is a function of the scanner parameters. If phase effects are removed this Noise Spread quantity is directly proportional to the expected value of the Hamming distance between scans with and without edge noise. The Noise …

Fundamental Frequency Switching Strategies Of A Seven-Level Hybrid Cascaded H-Bridge Multilevel Inverter, Zhong Du, Leon M. Tolbert, Burak Ozpineci, John N. Chiasson

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n − 1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and …

An Affordable Software Defined Radio, Thad B. Welch, Travis Kent, Cameron H.G. Wright, Michael G. Morrow

Electrical and Computer Engineering Faculty Publications and Presentations

This paper discusses the utilization of a relatively inexpensive wideband radio receiver in combination with a digital downconverter (DDC) based data recorder to capture and record real world radio signals. The resulting in-phase (I) and quadrature (Q) data files are then imported intoMATLAB for processing. This batch processing of real world radio signals allows for a tremendous amount of classroom flexibility in the discussion of software defined radio topics.