Engineering Commons^™

Electromagnetic Scattering Solutions For Digital Signal Processing, Jonathan Blackledge

Other resources

Electromagnetic scattering theory is fundamental to understanding the interaction between electromagnetic waves and inhomogeneous dielectric materials. The theory unpins the engineering of electromagnetic imaging systems over a broad range of frequencies, from optics to radio and microwave imaging, for example. Developing accurate scattering models is particularly important in the field of image understanding and the interpretation of electromagnetic signals generated by scattering events. To this end there are a number of approaches that can be taken. For relatively simple geometric configurations, approximation methods are used to develop a transformation from the object plane (where scattering events take place) to the …

An Improved Cube Cell Assembly For The Use With High Pressure/High Temperature Cubic Apparatus In Manufacturing Polycrystalline Diamond Compact Inserts, Kevin Christian Bach

Theses and Dissertations

The goal for this research was to reduce the current manufacturing cost of the polycrystalline diamond compact (PDC) inserts utilized in the natural gas and oil drilling industry while not reducing their current performance. Polycrystalline Diamond is added to the tungsten-carbide (WC) substrates commonly utilized in these applications because of its greater wear and thermal resistance. With the current cube cell design for the high-pressure/high-temperature apparatus, it is necessary to bond an extra WC substrate to the polycrystalline diamond insert to achieve the sizes generally ordered by the customers. The problem of bonding the extra WC substrate was solved by …

Classification, Clustering And Data-Mining Of Biological Data, Thomas Triplet

School of Computing: Dissertations, Theses, and Student Research

The proliferation of biological databases and the easy access enabled by the Internet is having a beneficial impact on biological sciences and transforming the way research is conducted. There are currently over 1,100 molecular biology databases dispersed throughout the Internet. However, very few of them integrate data from multiple sources. To assist in the functional and evolutionary analysis of the abundant number of novel proteins, we introduce the PROFESS (PROtein Function, Evolution, Structure and Sequence) database that integrates data from various biological sources. PROFESS is freely available at http://cse.unl.edu/~profess/. Our database is designed to be versatile and expandable and …

Total Storm Management Manual, Indiana Department Of Transportation

JTRP Other Publications and Reports

No abstract provided.

Ceas E-News 11.24.2009, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

Tues, Dec. 8, SEDP conference: 89 seniors offer 32 projects

Vision-Based Precision Landings Of A Tailsitter Uav, Paul Travis Millet

Theses and Dissertations

We present a method of performing precision landings of a vertical take-off and landing (VTOL) unmanned air vehicle (UAV) with the use of an onboard vision sensor and information about the aircraft's orientation and altitude above ground level (AGL). A method for calculating the 3-dimensional location of the UAV relative to a ground target of interest is presented as well as a navigational controller to position the UAV above the target. A method is also presented to prevent the UAV from moving in a way that will cause the ground target of interest to go out of view of the …

Mechanical Structures Resisting Anterior Instability In A Computational Glenohumeral Joint Model, Kevin Elmore

Theses and Dissertations

The glenohumeral joint is the most dislocated joint in the body due to the lack of bony constraints and dependence on soft tissue, primarily muscles and ligaments, to stabilize the joint. The goal of this study was to develop a computational model of the glenohumeral joint whereby joint behavior was dictated by articular contact, ligamentous constraints, muscle loading, and external perturbations. Validation of this computational model was achieved by comparing predicted results from the model to the results of a cadaveric experiment in which the relative contribution of muscles and ligaments to anterior joint stability was examined. The results showed …

In-Plane, All-Photonic Transduction Method For Silicon Photonic Microcantilever Array Sensors, Jong Wook Noh

Theses and Dissertations

We have invented an in-plane all-photonic transduction method for photonic microcantilever arrays that is scalable to large arrays for sensing applications in both bio- and nanotechnology. Our photonic transduction method utilizes a microcantilever forming a single mode rib waveguide and a differential splitter consisting of an asymmetric multimode waveguide and a Y-branch waveguide splitter. The differential splitter's outputs are used to form a differential signal that has a monotonic response to microcantilever deflection. A differential splitter using an amorphous silicon strip-loaded multimode rib waveguide is designed and fabricated to demonstrate the feasibility of the in-plane photonic transduction method. Our initial …

An Evaluation Of Quikscat Uhr Wind Product's Effectiveness In Determining Selected Tropical Cyclone Characteristics, Faozi Said

Theses and Dissertations

While the standard wind product (L2B) available operationally in near-real time from SeaWinds on QuikSCAT is only 25 km in resolution, QuikSCAT data can be enhanced to yield a 2.5 km ultra-high resolution (UHR) product. The latter can be used to help estimate Tropical Cyclone (TC) characteristics such as TC eye center and wind radii. Two studies are conducted in this thesis, in which QuikSCAT UHR wind product's effectiveness in estimating these TC characteristics is evaluated. First, a comparison is made between the analyst's choice of eye location based on UHR images and interpolated best-track position. In this analysis, the …

Neural Network Control Of A Class Of Nonlinear Discrete Time Systems With Asymptotic Stability Guarantees, Balaje T. Thumati, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a single and multi-layer neural network (NN) controllers are developed for a class of nonlinear discrete time systems. under a mild assumption on the system uncertainties, which include unmodeled dynamics and bounded disturbances, by using novel weight update laws and a robust term, local asymptotic stability of the closed-loop system is guaranteed in contrast with all other NN controllers where a uniform ultimate boundedness is normally shown. Simulation results are presented to show the effectiveness of the controller design. © 2009 AACC.

R-Factor: A New Parameter To Enhance Location Accuracy In Rssi Based Real-Time Location Systems, Mohammed Rana Basheer, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

The fundamental cause of localization error in an indoor environment is fading and spreading of the radio signals due to scattering, diffraction, and reflection. These effects are predominant in regions where there is no-line-of-sight (NLoS) between the transmitter and the receiver. Efficient algorithms are needed to identify the subset of receivers that provide better localization accuracy. © 2009 IEEE.

Neural Network Control Of Quadrotor Uav Formations, Travis Dierks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel framework for leader-follower formation control is developed for the control of multiple quadrotors unmanned aerial vehicles (UAVs) based on spherical coordinates. the control objective for the follower UAV is to track its leader at a desired- separation, angle of incidence, and a bearing by using an auxiliary velocity control. Then, a novel neural network (NN) control law for the dynamical system is introduced to learn the complete dynamics of the UAV including unmodeled dynamics like aerodynamic friction. Additionally, the interconnection dynamic errors between the leader and its followers are explicitly considered, and the stability of …

Structural Damage Localization With Tolerance To Large Time Synchronization Errors In Wsns, Guirong Yan, Shirley J. Dyke, Wei Song, Gregory Hackmann, Chenyang Lu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With Recent Technological Advances in Smart Sensor Platforms, Structural Condition Monitoring Implementations based on Wireless Sensor Networks (WSNs) Have Received Considerable Attention. Modal Identification is an Integral Step in Many Structural Condition Monitoring Systems. However, Accurate Time Synchronization is Not Always Possible, Leading to Incorrect Identification of the Mode Shapes. Although Strict Time Synchronization of the Wireless Sensors Has Been Viewed as Crucial for the Identification of Mode Shapes, a New Perspective is Taken Herein. the Distortion in the Identified Mode Shapes is Characterized and Accommodated. Then the Resulting Mode Shapes Are Used with a Flexibility-Based Damage Detection Approach to …

A Model Based Fault Detection And Accommodation Scheme For Nonlinear Discrete-Time Systems With Asymptotic Stability Guarantee, Balaje T. Thumati, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a fault detection and accommodation (FDA) framework is developed for unknown nonlinear discrete-time systems. the changes in the system dynamics due to the faults are modeled as a nonlinear function of state and input variables while the time profile of the fault is assumed to be exponentially developing. a fault is detected by monitoring the system states and reconstructing the fault dynamics using online approximators. the online approximator output is used first for fault detection and later reconfigured for accommodation. a stable adaptation law in discrete time is developed not only to characterize the faults but also …

The International Charter And Flood Mapping, Jie Shan

GIS Day

An overview of recent Purdue activities related to the International Charter for Space and Major Disasters, including general information about The Charter, 3 Indiana flood examples, and a summary of the lessons learned therefrom.

A Model To Study Cyber Attack Mechanics And Denial-Of-Service Exploits Over The Internet's Router Infrastructure Using Colored Petri Nets, Lawrence M. Healy

Master's Theses and Doctoral Dissertations

The Internet‟s router infrastructure, a scale-free computer network, is vulnerable to targeted denial-of-service (DoS) attacks. Protecting this infrastructure‟s stability is a vital national interest because of the dependence of economic and national security transactions on the Internet. Current defensive countermeasures that rely on monitoring specific router traffic have been shown to be costly, inefficient, impractical, and reactive rather than anticipatory.

To address these issues, this research investigation considers a new paradigm that relies on the systemic changes that occur during a cyber attack, rather than individual router traffic anomalies. It has been hypothesized in the literature that systemic knowledge of …

Gan Heterojunction Fet Device Fabrication, Characterization And Modeling, Qian Fan

Theses and Dissertations

This dissertation is focused on the research efforts to develop the growth, processing, and modeling technologies for GaN-based Heterojunction Field Effect Transistors (HFETs). The interest in investigating GaN HFETs is motivated by the advantageous material properties of nitride semiconductor such as large band gap, large breakdown voltage, and high saturation velocity, which make it very promising for the high power and microwave applications. Although enormous progress has been made on GaN transistors in the past decades, the technologies for nitride transistors are still not mature, especially concerning the reliability and stability of the device. In order to improve the device …

Variability In Construction Of Cement-Treated Base Layers: Probabilistic Analysis Of Pavement Life Using Mechanistic-Empirical Approach, Tyler J. Rogers

Theses and Dissertations

The primary objective of this research was to quantify the improvement in service life of a flexible pavement constructed using full-depth reclamation (FDR) in conjunction with cement stabilization when specified reductions in the spatial variability of specific construction-related parameters are achieved. This study analyzed pavement data obtained through field and laboratory testing of a reconstruction project in northern Utah. Data analyses included multivariate regression, Monte Carlo simulation, and mechanistic-empirical analyses of a model pavement structure. The results of the research show a steadily increasing trend in 28-day unconfined compressive strength of the cement-treated base (CTB) layer with increasing reductions in …

Automated Calibration Of The Gssha Watershed Model: A Look At Accuracy And Viability For Routine Hydrologic Modeling, Kayson M. Shurtz

Theses and Dissertations

The goal of hydrologic models is to accurately predict a future event of a given magnitude. Historic data are often used to calibrate models to increase their ability to forecast accurately. The GSSHA model is a distributed model that uses physical parameters and physics based computations to compute water flow from cell to cell based on a 2 dimensional grid. The goal of calibration is to obtain good estimates for the actual parameters of the watershed. These parameters should then transfer to other storm events of different magnitudes more easily than an empirical model. In conducting this research three watersheds …

Improved Implementation Of Kirkwood-Buff Solution Theory In Periodic Molecular Simulations, Joseph W. Nichols, Stan G. Moore, Dean R. Wheeler

Faculty Publications

Kirkwood-Buff (KB) solution theory is a means to obtain certain thermodynamic derivatives from knowledge of molecular distributions. In actual practice the required integrals over radial distribution functions suffer inaccuracies due to finite-distance truncation effects and their use in closed systems. In this work we discuss how best to minimize these inaccuracies under traditional KB theory. In addition we implement a method for calculating KB quantities in molecular simulations with periodic boundary conditions and particularly within the canonical ensemble. The method is based on a finite-Fourier-series expansion of molecular concentration fluctuations and leads to more reliable results for a given computational …

Manifestation Of Kohn Anomaly In 1/F Fluctuations In Metallic Carbon Nanotubes, Ju Hee Back, Cheng-Lin Tsai, Sunkook Kim, Saeed Mohammadi, Moonsub Shim

Birck and NCN Publications

Low-frequency noise in metallic single walled carbon nanotubes is shown to be strongly dependent on the Fermi level position and the applied electric field across the nanotube. Resonance-like enhancement observed near optical phonon energy only when the Fermi level lies near the Dirac point is correlated to Raman G-band softening and broadening. The results suggest that the competition between zone-center and zone-boundary phonon scattering is the underlying origin of the large enhancement and resonance-like behavior of 1/f noise.

Slab-Coupled Optical Fiber Sensors For Electric Field Sensing Applications, Richard S. Gibson

Theses and Dissertations

This dissertation presents the creation of slab coupled optical sensors (SCOS) for electric field sensing applications. SCOS devices utilize the benefits of an optical fiber system for high bandwidth and low electromagnetic interference. These sensors are fabricated by means of mode coupling between a small section of D-shaped optical fiber (D-fiber) with a multi-mode electro-optic slab waveguide. Electric field detection is accomplished by monitoring the behavior of the resonances, seen as transmission dips in the D-fiber transmission, as they shift with electric fields. The novelties of SCOS devices include their small compact nature, potential for sensor multiplexing and a dielectric …

Quantifying And Resolving Multiple Vector Transformants In S. Cerevisiae Plasmid Libraries, Thomas C. Scanlon, Elizabeth C. Gray, Karl E. Griswold

Dartmouth Scholarship

In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the …

Improving Accuracy In Microwave Radiometry Via Probability And Inverse Problem Theory, Derek Lavell Hudson

Theses and Dissertations

Three problems at the forefront of microwave radiometry are solved using probability theory and inverse problem formulations which are heavily based in probability theory. Probability theory is able to capture information about random phenomena, while inverse problem theory processes that information. The use of these theories results in more accurate estimates and assessments of estimate error than is possible with previous, non-probabilistic approaches. The benefits of probabilistic approaches are expounded and demonstrated. The first problem to be solved is a derivation of the error that remains after using a method which corrects radiometric measurements for polarization rotation. Yueh [1] proposed …

Ceas E-News 11.19.2009, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

Five honored with 2009 CEAS Awards for outstanding work

Long-Term Prediction Of Time Series By Combining Direct And Mimo Strategies, Souhaib Ben Taieb, Gianluca Bontempi, Antti Sorjamaa, Amaury Lendasse

Engineering Management and Systems Engineering Faculty Research & Creative Works

Reliable and Accurate Prediction of Time Series over Large Future Horizons Has Become the New Frontier of the Forecasting Discipline. Current Approaches to Long-Term Time Series Forecasting Rely Either on Iterated Predictors, Direct Predictors Or, More Recently, on the Multi-Input Multi- Output (MIMO) Predictors. the Iterated Approach Suffers from the Accumulation of Errors, the Direct Strategy Makes a Conditional Independence Assumption, Which Does Not Necessarily Preserve the Stochastic Properties of the Time Series, While the MIMO Technique is Limited by the Reduced Flexibility of the Predictor. the Paper Compares the Direct and MIMO Strategies and Discusses their Respective Limitations to …

An Alpha Derivative Formulation Of The Hamilton-Jacobi-Bellman Equation Of Dynamic Programming, John Seiffertt

Electrical and Computer Engineering Faculty Research & Creative Works

The time scales calculus, which includes the study of the alpha derivative, is an emerging key area in mathematics. We extend this calculus to Approximate Dynamic Programming. in particular, we investigate application of the alpha derivative, one of the fundamental dynamic derivatives of time scales. We present an alpha-derivative based derivation and proof of the Hamilton-Jacobi-Bellman equation, the solution of which is the fundamental problem in the Held of dynamic programming. by drawing together the calculus of time scales and the applied area of stochastic control via Approximate Dynamic Programming, we connect two major fields of research. © 2009 IEEE.

Adaptive Dynamic Programming-Based Optimal Control Of Unknown Affine Nonlinear Discrete-Time Systems, Travis Dierks, Balaje T. Thumati, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

Discrete time approximate dynamic programming (ADP) techniques have been widely used in the recent literature to determine the optimal or near optimal control policies for nonlinear systems. However, an inherent assumption of ADP requires at least partial knowledge of the system dynamics as well as the value of the controlled plant one step ahead. in this work, a novel approach to ADP is attempted while relaxing the need of the partial knowledge of the nonlinear system. the proposed methodology entails a two-part process: online system identification and offline optimal control training. First, in the identification process, a neural network (NN) …

Decentralized Control Of Large Scale Interconnected Systems Using Adaptive Neural Network-Based Dynamic Surface Control, Shahab Mehraeen, Sarangapani Jagannathan, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

A novel decentralized controller using the dynamic surface control (DSC) is proposed for a class of uncertain large scale interconnected nonlinear systems in strict feedback form while relaxing the "explosion of complexity" problem which is observed in the typical backstepping approach. the matching condition is not assumed when dealing with the interconnection terms. Neural networks (NNs) are utilized to approximate the uncertainties in both subsystem and interconnected terms. by using novel NN weight update laws, it is demonstrated using Lyapunov stability that the closed-loop signals are asymptotically stable in the presence of NN approximation errors in contrast with the uniform …

East Bay Energy Consortium Siting Study Kickoff Meeting, November 17, 2009, East Bay Energy Consortium

East Bay Energy Consortium Meeting Minutes

No abstract provided.