Digital Commons Network^™

A Duplex Theory Of Spike Coding In The Early Stages Of The Auditory System, Ismail Uysal, Harsha Sathyendra, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We propose a duplex theory of spike coding in the early stages of the auditory system based on the intensity and noise levels of the acoustic stimuli. According to this concept, at low intensity levels, where auditory nerve firings cannot generate a high enough synchrony among neuron ensembles, rate coding is more likely favored against phase-locking via synchrony coding. To the contrary, at conversational intensity levels, phase synchrony coding is preferred due to its superior and highly noise robust performance. The theory is supported by both evidence from biology, as well as from experimental simulations using biologically plausible models of …

Manufacturable Process And Tool For High Performance Metal/High-K Gate Dielectric Stacks For Sub-45 Nm Cmos & Related Devices, Aarthi Venkateshan

All Dissertations

Off state leakage current related power dominates the CMOS heat dissipation problem of state of the art silicon integrated circuits. In this study, this issue has been addressed in terms of a low-cost single wafer processing (SWP) technique using a single tool for the fabrication of high-κ dielectric gate stacks for sub-45 nm CMOS. A system for monolayer photoassisted deposition was modified to deposit high-quality HfO2 films with in-situ clean, in-situ oxide film deposition, and in-situ anneal capability. The system was automated with Labview 8.2 for gas/precursor delivery, substrate temperature and UV lamp. The gold-hafnium oxide-aluminum (Au-HfO2-Al) stacks processed in …

Spatio-Temporal Anomaly Detection For Mobile Devices, Guarav Tandon, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

With the increase in popularity of mobile devices, there has been a significant rise in mobile related security problems. The biggest threat for a mobile subscriber is lost or stolen device, which can lead to confidential data leakage, identity theft, misuse, impersonation, and high service charges. A significant amount of time may elapse between losing a device and disabling it through the service provider, during which an unauthorized malicious user may gain access and incur severe damage. We propose a probabilistic approach to spatio-temporal anomaly detection and evaluate smoothing techniques for sparse data. Our approach outperforms Markov Chain in experiments …

Optimal Scheduling Of Generator Maintenance Using Modified Discrete Particle Swarm Optimization, Yusuf Yare, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a modified discrete particle swarm optimization (PSO) based technique for generating optimal preventive maintenance schedule of generating units for economical and reliable operation of a power system while satisfying system load demand and crew constraints. While GA and other analytical methods might suffer from premature convergence and the curse of dimensionality, heuristics based swarm intelligence can be an efficient alternative. PSO is known to effectively solve large scale multi-objective optimization problems. Here, a modified discrete PSO approach is proposed for the GMS optimization problem in order to overcome the limitations of the conventional methods and come up …

Making The Power Grid More Intelligent, Salman Mohagheghi, Ronald G. Harley, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Summary form only given. This paper focuses on the applications of intelligent techniques for improving the performances of the power system controllers. Intelligent control techniques lay the foundation of the next generation of nonlinear controllers and have the advantage of further improving the controller's performance by incorporating heuristics and expert knowledge into its design. Most of these techniques are independent of any mathematical model of the power system, which proves to be a considerable advantage.

A Time-To-First-Spike Cmos Image Sensor, Xiaochuan Guo, Xin Qi, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A time-to-first spike (TTFS) imager was designed such that each pixel outputs a single digital pulse whose timing encodes pixel illumination. For still image applications, this time representation provides a tremendous increase in dynamic range, similar to that of other existing time-based imagers. However, a major advantage of the TTFS imager is that this wide dynamic range can be achieved even for 30 frames/s video applications. A prototype 32x32 TTFS image sensor was fabricated in AMI 0.5 μm CMOS technology. The prototype chip demonstrates a 104 dB dynamic range (limited by the optical equipment), 42 μV/electron conversion gain, 1.25 nA/cm …

Clock-Free Nanowire Crossbar Architecture Based On Null Convention Logic (Ncl), Ravi Bonam, Shikha Chaudhary, Yadunandana Yellambalase, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

There have been numerous nanowire crossbar architectures proposed till date, although all of them are envisioned to be synchronous (i.e., clocked). The clock is an important part in a circuit and it needs to be connected to all the components to synchronize their operation. Considering non-deterministic nature of nanoscale integration, realizing them on a nano wire crossbar system would be quite cumbersome. Unlike the conventional clocked counterparts, a new clock-free crossbar architecture is proposed to resolve the issues with clocked counterparts in this paper, where the use of clock is eliminated from the architecture. This has been done by implementing …

Decentralized Control Of Multiple Uavs For Perimeter And Target Surveillance, Derek B. Kingston

Theses and Dissertations

With the recent development of reliable autonomous technologies for small unmanned air vehicles (UAVs), the algorithms utilizing teams of these vehicles are becoming an increasingly important research area. Unfortunately, there is no unified framework into which all (or even most) cooperative control problems fall. Five factors that affect the development of cooperative control algorithms are objective coupling, communication, completeness, robustness, and efficiency. We classify cooperative control algorithms by these factors and then present three algorithms with application to target and perimeter surveillance and a method for decentralized algorithm design. The primary contributions of this research are the development and analysis …

Transitions Between Hover And Level Flight For A Tailsitter Uav, Stephen R. Osborne

Theses and Dissertations

Vertical Take-Off and Land (VTOL) Unmanned Air Vehicles (UAVs) possess several desirable characteristics, such as being able to hover and take-off or land in confined areas. One type of VTOL airframe, the tailsitter, has all of these advantages, as well as being able to fly in the more energy-efficient level flight mode. The tailsitter can track trajectories that successfully transition between hover and level flight modes. Three methods for performing transitions are described: a simple controller, a feedback linearization controller, and an adaptive controller. An autopilot navigational state machine with appropriate transitioning between level and hover waypoints is also presented. …

Combined Spatial Filter And Relay Systems In Rotating Compensator Ellipsometer/Polimeter, Martin M. Liphardt, Blaine D. Johs, Jeffrey S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Low aberration relay systems modified to perform as spatial filters in rotating compensator ellipsometer, polarimeter and the like systems.

Particle Filter Based Mosaicking For Forest Fire Tracking, Justin Mathew Bradley

Theses and Dissertations

Using autonomous miniature air vehicles (MAVs) is a cost-effective, simple method for collecting data about the size, shape, and location characteristics of a forest fire. However, noise in measurements used to compute pose (location and attitude) of the on-board camera leads to significant errors in the processing of collected video data. Typical methods using MAVs to track fires attempt to find single geolocation estimates and filter that estimate with subsequent observations. While this is an effective method of resolving the noise to achieve a better geolocation estimate, it reduces a fire to a single point or small set of points. …

A Wind And Rain Backscatter Model Derived From Amsr And Seawinds Data, Seth Niels Nielsen

Theses and Dissertations

The SeaWinds scatterometers aboard the QuikSCAT and ADEOS II satellites were originally designed to measure wind vectors over the ocean by exploiting the relationship between wind-induced surface roughening and the normalized radar backscatter cross-section. Recently, an algorithm for simultaneously retrieving wind and rain (SWR) from scatterometer measurements was developed that enables SeaWinds to correct rain-corrupted wind measurements and retrieve rain rate data. This algorithm is based on co-locating Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR) and SeaWinds on QuikSCAT data. In this thesis, a new wind and rain radar backscatter model is developed for the SWR algorithm using a …

Compilation And Generation Of Multi-Processor On A Chip Real-Time Embedded Systems, Randall S. Klingler

Theses and Dissertations

Current FPGA technology has advanced to the point that useful embedded System-on-Programmable-Chips (SoPC)s can now be designed. The Real Time Processor (RTP) project leverages the advances in FPGA technology with a system architecture that is customizable to specific real-time applications. The design and implementation of the framework for architecting such a system from ANSI-C code is presented. The Small Device C Compiler (SDCC) was retargeted to the RTP architecture and extended to produce a generator directive file. The RTPGen hardware generator was created to consume the directive file and produce a highly customized top-level structural VHDL file that can be …

Computational Analyses Of High Power Microwave Slotted Array Antennas For Mobile Applications, John Topolski

Electrical and Computer Engineering ETDs

Computational Analyses of High Power Microwave Slotted Array Antennas for Mobile Applications

Convergence Or Divergence: Technology Policies And User Expectations

ACUTA: Other Publications

The Forum

Since 1997, the annual ACUTA Forum for Strategic Leadership in Communications Technology has provided a unique opportunity for campus leaders to exchange ideas and discuss issues relevant to the use of technology in meeting the goals of higher education. Held in conjunction with ACUTA's Annual Conference and Exhibtion, this forum brings together men and women of vision, foresight, and authority to discuss strategic directions for the campus of the future.

Goals

• To provide a venue for the examination of issue and challenges facing the higher education community as we grapple with planning, financing, and implementing technology on our …

A New Battery/Ultracapacitor Energy Storage System Design And Its Motor Drive Integration For Hybrid Electric Vehicles, Shuai Lu, Keith Corzine, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a new energy storage system (ESS) design, including both batteries and ultracapacitors (UCs) in hybrid electric vehicle (HEV) and electric vehicle applications. The conventional designs require a dc-dc converter to interface the UC unit. Herein, the UC can be directly switched across the motor drive dc link during the peak power demands. The resulting wide voltage variation due to UC power transfer is addressed by the simple modulator that is introduced in this paper, so that the motor drive performance is not disrupted. Based on this new methodology, this paper further introduces two ESS schemes with different …

A Unique Ultracapacitor Direct Integration Scheme In Multilevel Motor Drives For Large Vehicle Propulsion, Shuai Lu, Keith Corzine, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a new set of methods to directly integrate ultracapacitor banks into cascaded multilevel inverters that are used for large vehicle propulsion. The idea is to replace the regular dc-link capacitors with ultracapacitors in order to combine the energy storage unit and motor drive. This approach eliminates the need for an interfacing dc-dc converter and considerably improves the efficiency of regenerative braking energy restoration in large vehicles using multilevel converters. Utilizing the proposed modulation control set, the two cascaded inverters can have their dc voltage levels maintained at any ratio (even a noninteger ratio) or dynamically varied over …

Steady State Formulation Of Facts Devices Based On Ac/Ac Converters, J. M. Ramirez, J. M. Gonzalez, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Here the analysis on the inclusion of a pulse width modulated (PWM) ac link unified power flow controller into a power flow program is discussed. Similarly, a PWM series compensator is connected to the power system to regulate the active power flow on the corresponding transmission line. Details of the Newton-Raphson's power flow algorithm are exhibited. Results of simulation are presented on a 39-buses power system.

Advanced Control And Analysis Of Cascaded Multilevel Converters Based On P-Q Compensation, Shuai Lu, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces new controls for the cascaded multilevel power converter. This converter is also sometimes referred to as a ldquohybrid converterrdquo since it splits high-voltage/low-frequency and low-voltage/pulsewidth-modulation (PWM)-frequency power production between ldquobulkrdquo and ldquoconditioningrdquo converters respectively. Cascaded multilevel converters achieve higher power quality with a given switch count when compared to traditional multilevel converters. This is a particularly favorable option for high power and high performance applications such as naval ship propulsion. This paper first presents a new control method for the topology using three-level bulk and conditioning inverters connected in series through a three-phase load. This control avoids …

Optimization Methods Of Laser Induced Breakdown Spectroscopy (Libs) And The Self-Absorption Problem, Olodia Ayed Taha Nassef

Electrical & Computer Engineering Theses & Dissertations

Laser Induced Breakdown Spectroscopy (LIBS) is a well-established technique for determining elemental composition. Compared to conventional methods, its ability to analyze solids, liquids, and gases with little or no sample preparation makes it more versatile and ideal for field, multi-element, and in-situ analysis. The method can be certified for analytical applications of interest in environmental monitoring and quality control processes. Previous work has demonstrated that several different experimental parameters (e.g. laser wavelength, repetition rate, interaction geometry, surface conditions) may affect the effective analytical possibilities of the method. Therefore, many studies have been devoted to optimize such parameters in a way …

Distributed Knowledge Discovery In Large Scale Peer-To-Peer Networks, Sachin Shetty

Computational Modeling & Simulation Engineering Theses & Dissertations

Explosive growth in the availability of various kinds of data in distributed locations has resulted in unprecedented opportunity to develop distributed knowledge discovery (DKD) techniques. DKD embraces the growing trend of merging computation with communication by performing distributed data analysis and modeling with minimal communication of data. Most of the current state-of-the-art DKD systems suffer from the lack of scalability, robustness and adaptability due to their dependence on a centralized model for building the knowledge discovery model. Peer-to-Peer networks offer a better scalable and fault-tolerant computing platform for building distributed knowledge discovery models than client-server based platforms. Algorithms and communication …

Simulations Of Intracellular Calcium Release In Response To High-Intensity, Ultrashort Electric Pulse, Anh Nguyen

Electrical & Computer Engineering Theses & Dissertations

Calcium modulation is an important signaling process and could even contribute to cell apoptosis through ionic-induced perturbations in trans-membrane potential at the mitochondria. In this research, the numerical study constitutes a first step in quantitatively probing the time- and spatially-dependent modulation of calcium dynamics through the application of external electrical fields. The research uses both widely accepted deterministic continuum and discrete stochastic intracellular calcium models coupling with external electric field, with a focus on high-intensity ultrashort pulse electrical field.

For deterministic continuum intracellular calcium models with electric field assisted, numerical simulations for electrically induced, intra-cellular calcium-release from the endoplasmic reticulum …

Early Time Charge Replenishment Of The Power Delivery Network In Multi-Layer Pcbs, Giuseppe Selli, Matteo Cocchini, James L. Knighten, Bruce Archambeault, Jun Fan, Samuel R. Connor, Antonio Orlandi, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The investigation of decoupling issues has been extensively treated in the literature in both the frequency and the time domain [1-9]. The two domains describe from different perspectives the same physical phenomenon, being related by a Fourier transform. In this article, well known decoupling issues usually addressed in the frequency domain [1,2] are discussed in the time domain. Moreover, some modeling issues related to the cavity model approach are discussed and, in particular, the circuit extraction feature associated with this methodology is utilized throughout the article to carry out the time domain simulations within a SPICE based-tool. The depletion of …

Spice-Compatible Cavity And Transmission Line Model For Power Bus With Narrow Slots, Gang Feng, Yaojiang Zhang, James L. Drewniak, Lin Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

Segmental lumped circuits are derived from coupled transmission line model for a narrow slot on the power bus. Both electric and magnetic coupling are taken into account by distributed inductances and capacitances. Then a SPICE- compatible circuit model for the power bus with the narrow slot is proposed. In this model, the segmental lumped circuits are connected to the equivalent circuit, which is derived by a hybrid cavity model and segmentation method for irregular power/ground planes. The model is validated by comparing with the calculations of finite element method (FEM) for the self or mutual impedances of the two port …

Double Statistical Distribution Of Conductivity And Aspect Ratio Of Inclusions In Dielectric Mixtures At Microwave Frequencies, Marina Koledintseva, Richard E. Dubroff, Robert W. Schwartz, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

An analytical model of a composite dielectric presented in this paper is the extension of Maxwell Garnett formulation. It takes into account the simultaneous statistical (Gaussian) distribution of conductivity and aspect ratio of inclusions. The inclusions are randomly oriented elongated conducting spheroids at concentrations below the percolation threshold. The formulation presented herein is limited to microwave frequencies. However, taking subtle frequency-dependent effects that play important part at optical frequencies into account is straightforward. Some results of computations of microwave complex effective permittivity of composites with different input parameters have been obtained using analytical and numerical integration in Maple 10 software. …

Web-Based Design And Analysis Projects For A Junior Level Integrated Circuits Course, David Braun

Electrical Engineering

Just as the electronics industry can increase productivity with web-based tools, web-based design offers opportunities to improve education in the area of electronics and integrated circuits. This work describes a variety of web based design and analysis projects for a junior level electronics course and assesses their impact on student learning. Since the course using the projects comprises the second quarter of electronics instruction subsequent to introductory circuit analysis courses, the projects focus on relatively well-defined electronics subsystems. The projects exercise students’ skills with a range of course learning objectives, ranging from lower level calculation, analysis and circuit simulation objectives …

Interdisciplinary Team Teaching: Lessons For Engineering Instructors From A Capstone Course In Environmental Studies, David Braun, Emmit B. Evans, Randall Knight, Thomas Ruehr

Electrical Engineering

The capstone course teaches students to analyze global environmental issues, resources, and human activities with a systems approach based on scientific, economic, political, social and ethical perspectives. Such an intrinsically multifaceted subject demands interdisciplinary treatment. To deliver the interdisciplinary treatment, the course uses diverse faculty teams comprised of faculty from fields in the natural and social sciences, engineering, and business. This work describes the interdisciplinary team teaching strategies adopted for the course and how they evolved with subsequent offerings of the course. We present assessment data measuring how well students achieve course objectives. Finally, experience gleaned from this course for …

Three Enabling Technologies For Vision-Based, Forest-Fire Perimeter Surveillance Using Multiple Unmanned Aerial Systems, Ryan S. Holt

Theses and Dissertations

The ability to gather and process information regarding the condition of forest fires is essential to cost-effective, safe, and efficient fire fighting. Advances in sensory and autopilot technology have made miniature unmanned aerial systems (UASs) an important tool in the acquisition of information. This thesis addresses some of the challenges faced when employing UASs for forest-fire perimeter surveillance; namely, perimeter tracking, cooperative perimeter surveillance, and path planning. Solutions to the first two issues are presented and a method for understanding path planning within the context of a forest-fire environment is demonstrated. Both simulation and hardware results are provided for each …

Optimization Of Nano-Magneto-Optic Sensitivity Using Dual Dielectric Layer Enhancement, Aaron R. Hawkins, J. D. Maas, S. Wang, A. Barman, Holger Schmidt, S. Kwon, B. Harteneck, S. Cabrini, J. Bokor

Faculty Publications

We discuss maximization of the sensitivity of magneto-optical detection of single nanomagnets. We show that a combination of optimized dielectric coating on the magnets with an antireflection coated substrate can increase the areal magneto-optic sensitivity by about three orders of magnitude in the deep nanometer range. A dual layer nanofabrication process is developed to implement this approach, and magnetization switching of single nickel nanomagnets with 50 nm diameter is demonstrated.

Current-Induced Breakdown Of Carbon Nanofibers, Makoto Suzuki, Yusuke Ominami, Quoc Ngo, Cary Y. Yang, Alan M. Cassell, Jun Li

Electrical and Computer Engineering

We present a study of high-field transport in carbon nanofibers (CNFs) and breakdown phenomena due to current stress. In situ measurements with scanning transmission electron microscopy reveal that the failure mode of CNFs is strongly related to the morphology of graphite layers comprising CNFs. Comparison with carbon nanotube (CNT) breakdown is made, demonstrating that the current capacity of CNFs is described by a similar model as that of CNTs with a modification of the current capacity of each graphitic layer. The maximum current density is correlated with resistivity, leading to the conclusion that lower resistivity results in higher current capacity …