Engineering Commons^™

Improvement Of Prony's Method Of System Identification Vianonlinear Parameter Transformation, C. Wu

Journal of the Arkansas Academy of Science

This paper presents an approach to improve Prony’s method of identifying a linear time-invariant system. The method is based on a nonlinear transformation of parameters, which leads to data averaging. The method yields better results than a direct application of the least squares approach to Prony’s method. A numerical example is given to demonstrate the improvement attained by the new algorithm. Signals are assumed to be contaminated by zero-mean Gaussian white noise.

Growth Rate Calculations For Epitaxially Grown Thin Films, D. Bullock

Journal of the Arkansas Academy of Science

No abstract provided.

Studies On Field Stabilization Methods To Prevent Surficial Slope Failures Of Earth Fill Dams, Venkata S. Dronamraju

Civil Engineering Dissertations - Archive

Surficial failures are occurring frequently on the slopes of earthfill dams which are predominantly rainfall induced. Desiccation cracks form on the slope surface during dry environment which accelerates infiltration during rainfall. Infiltration causes increase of pore water pressures and saturation of soil mass in top layer resulting in surficial failures. Numerous surficial failures occurred on the slope of earthfill dams maintained by The United States Army Corps. of Engineers. The current research is undertaken at the University of Texas at Arlington with an objective of exploring the best field stabilization method to mitigate these surficial failures.Two sites, Joe Pool Dam …

Kentucky Traffic Collision Facts 2008 Report, Kentucky Transportation Center, Kentucky State Police

Kentucky Transportation Center Research Report

KENTUCKY’S TRAFFIC COLLISION FACTS report for 2008 is based on collision reports submitted to the Kentucky State Police Records Branch. As required by Kentucky Revised Statutes 189.635, “every law enforcement agency whose officers investigate a vehicle accident of which a report must be made...shall file a report of the accident...within ten days after investigation of the accident upon forms supplied by the bureau.” The stated purpose of this requirement is to utilize data on traffic collisions for such purposes as will improve the traffic safety program in the Commonwealth. Data contained in this report are based solely on the observations …

Economic Sustainability Of Remote Access Networking Classrooms, C Nuangjamnong, S P. Maj, D Veal

EDU-COM International Conference

Within the higher education domain, there is a prevalent belief that e-learning, virtual classroom and tele-education are essential requirements for the long-term effectiveness and success of educational institutions. Many information technologies have been adopted to assist studying and learning remotely and are hence potentially beneficial to students, teachers and educational providers. For educational providers, the benefits are that there are no physical or geographical limits to the number of students that can be enrolled in a course of study. However, within the field of network technology, students must actually use network devices during their studies. This is important not only …

Optimization In Multi-Agent Systems : Structures And Procedures, Ingo Stengel

Theses

The main advantage for the use of agent technology is in the capacity of agents to represent the interests of individual entities and to act autonomously on their behalf. In multi-agent systems this involves communication, coordination and negotiation.

The focus of this dissertation is to find ways to optimize multi-agent systems at different levels by taking into consideration their structure and the procedures used. As optimization depends to a large extent on the problem to be solved, group forming scenarios, in which self-interested agents compete to form and join groups, have been selected here for consideration. Optimization issues are discussed …

Concept Detection: Convergence To Local Features And Opportunities Beyond, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky

Research Collection School Of Computing and Information Systems

No abstract provided.

Preparation And Characterization Of (Gesbte)) Semiconductors For Phase-Change Optical Storage, Hessa Ali Humeid Al-Shamisi

Theses

In the last decade, the phase change optical recording based upon chalcogenide glasses has advanced remarkably at full-scale commercial applications in the form of rewritable compact disks (CD-RWs). The principle of phase-change optical recording is based on a thermally induced reversible transformation between amorphous and crystalline phases. The search for recording materials possessing fast crystallization rate and long data retention has been pursued. Research results have revealed that Ge-Sb-Te compounds exhibit fast crystallization, which has been explained in terms of their single-phase structure.

In the present work, electrical properties of Ge-Sb-Te thin films using Impedance Spectroscopy, Current-Voltage, and Capacitance-Voltage techniques …

Orthogonal Cutting Of Bone, Donal Mccrohan

Theses

The cutting of bone has been undertaken for many centuries. Research in this area is contnually progressing to achieve an efficient cutting action while reducing recovery time and rauma to the patient.

Orthogonal cutting is defined where the cutting edge of the tool is set in a position that is perpendicular to the direction of relative work or tool motion. The failure mechanisms involved in the cutting of bone, their direct relationships to cutting tool geometry and cutting direction for orthogonal cutting are not accurately defined or quantified. A study of the orthogonal cutting behaviour of bone initiated in the …

Sediment Budgets In The Irish Estuarine Environment, Kevin Motherway

Theses

A sediment budget is the quantification of sediment sources and sinks for natural physical systems such as rivers and estuaries.

This thesis has developed estuarine sediment budgets for Cork Harbour, Kinsale Harbour and Youghal Harbour. The thesis includes a literature review of the properties of sediment, river and estuary related sediment transport, sediment management and sediment related legislation and the approaches used to develop a sediment budget for an estuary system.

An extensive study of riverine suspended sediments discharging to the estuaries has been undertaken. Both surface grab samples and depth integrating suspended sediment samples were collected, tested and analysed. …

Mesh Mac Enabling Mesh Networking Over Ieee 802.15.4 Mac Layer, Panneer Selvan Muthukumaran

Theses

Wireless sensor network is a network of sensor nodes that function in a cooperative manner to monitor the changes in the physical environment. Wireless sensor networks are used in environment and habitat monitoring, healthcare applications, building automation, and traffic control to name a few. Typically, wireless sensor node is a low power embedded device which consists of a microcontroller, sensors, wireless transceiver and a battery. These devices are usually distributed in a physical environment which makes it difficult to maintain the network manually.

The IEEE 802.15.4 and Zigbee are considered as standard protocols for wireless sensor networks. The IEEE 802.15.4 …

Management Framework For Hybrid Wireless Networks, Chong Shen

Theses

The objective of the Hybrid Wireless Network with dedicated Relay Nodes (HWN*) architecture is to interface the Base Station (BS) Oriented Mobile Network (BSON) and the 802.fix based Mobile Ad hoc Wireless Network (MANET) so that one system can be utilised as an alternative radio access network for data transmissions, while the incorporation of Relay Nodes (RN) is to extend the communication coverage, optimise medium resource sharing, increase spatial reuse opportunity, stabilise MANET link and create more micro-cells. The HWN* keeps the existing cellular infrastructure and a Mobile Terminal (MT) can borrow radio resources from other cells via secure multi-hop …

Container Management And Monitoring Using Sensor Networks, Daniel Rogóz

Theses

The purpose of this project was to develop a functional prototype of a container management and monitoring system, which allows identification and tracking of shipping containers in a port terminal from the moment they enter a port to when they depart for their final destination.

Such system can significantly reduce the labor and time costs associated with organizational mistakes that can occur when containers are being on/off-loaded, moved and stacked in tiers for transfer to the rail or road network. It can be used to streamline the container transport, optimize the order of container on/off-loading and placement, as well as …

Efficient Mrf Approach To Document Image Enhancement, Tayo Obafemi-Ajayi, Gady Agam, Ophir Frieder

Electrical and Computer Engineering Faculty Research & Creative Works

Markov random field (MRF) based approaches have been shown to perform well in a wide range of applications. Due to the iterative nature of the algorithm, the computational cost of such applications is normally high. In the context of document image analysis, where numerous documents have to be processed, this computational cost may become prohibitive. We describe a novel approach to document image enhancement using MRF. We show that by using domain specific knowledge, we are able to substantially improve computational performance by an order of magnitude. Moreover, in contrast to known techniques where patch initialization is arbitrary, in the …

A Comparison Of Mlp, Rnn And Esn In Determining Harmonic Contributions From Nonlinear Loads, Jing Dai, Pinjia Zhang, Joy Mazumdar, Ronald G. Harley, G. K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

With the wide use of power electronics devices, harmonic currents are being injected into the power system, known as "harmonic pollution". Although IEEE standards [1][2] have required the utilities and customers to limit the amount of harmonic current and voltage, the practical evaluation is complicated, as it is difficult to separate the contributions from the utilities and customers. a neural network-Based harmonic current prediction scheme was previously proposed by the authors to estimate the true harmonic current attributed to the nonlinearity of the load, instead of the distorted power supply. to test the feasibility of different types of neural networks …

Noise Coupling Between Signal And Power/Ground Nets Due To Signal Vias Transitioning Through Power/Ground Plane Pair, Jun Fan, Matteo Cocchini, Bruce Archambeault, James L. Knighten, James L. Drewniak, Samuel Connor

Electrical and Computer Engineering Faculty Research & Creative Works

Signal vias are often used to move a signal from one PCB layer to another. as a result, these vias can penetrate power/ground plane pair and cause noise coupling (crosstalk) between signal and power/ground nets. This paper studies the noise coupling mechanism using a segmentation approach combined with a via capacitance model and a plane-pair cavity model. Noise coupling from signal to power/ground, and vice versa, is demonstrated in the modeling results.

Efficient Uncertainty Quantification Applied To The Aeroelastic Analysis Of A Transonic Wing, Serhat Hosder, Robert W. Walters, Michael Balch

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The application of a Point-Collocation Non-Intrusive Polynomial Chaos method to the uncertainty quantification of a stochastic transonic aeroelastic wing problem has been demonstrated. The variation in the transient response of the first aeroelastic mode of a three-dimensional wing in transonic flow due to the uncertainty in free-stream Mach number and angle of attack was studied. A curve-fitting procedure was used to obtain time-independent parameterization of the transient aeroelastic responses. Among the uncertain parameters that characterize the time-dependent transients, the damping factor was chosen for uncertainty quantification, since this parameter can be thought as an indicator for flutter. Along with the …

Nonlinear H(Infinity) Missile Longitudinal Autopilot Design With Theta-D Method, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear H 1 control technique, called μ¡D H 1 method, is employed to design a missile longitudinal autopilot. The μ ¡D H 1 design has the same structure as that of linear H 1 , except that the two Riccati equations that are part of the solution process are state dependent. The μ ¡D technique yields suboptimal solutions to nonlinear optimal control problems in the sense that it provides an approximate solution to the Hamilton-Jacobi-Bellman (HJB) equation. It is also shown that this method can be used to provide an approximate closed-form solution to the …

Technology And Signal Processing For Brain-Machine Interfaces, Justin C. Sanchez, Jose C. Principe, Toshikazu Nishida, Rizwan Bashirullah, John G. Harris, José A.B. Fortes

Electrical and Computer Engineering Faculty Research & Creative Works

Brain-machine interfaces (BMIs) aid disabled humans. BMI systems face challenges such as interfacing with neural tissue, selecting the most appropriate control signals, acquiring data and decoding patient intent in implantable or wearable computers. They must be able to adapt to different variety of behavioral states. Today's hybrid BMI systems consume less power and are made to chronically extract control commands from the nervous system. In terms of signal processing approaches, one challenge for BMI data analysis is learning how to handle large multi-input multi-output systems with signal representations that span continuous and discrete time. BMI systems also need sufficient information …

Anomalous Magnetic Ordering In Prba₂Cu₄O₈ And Cmba₂Cu₃O₇, H. A. Blackstead, M. P. Smylie, William B. Yelon, Qingsheng Cai, Mehmet Kahveci

Physics Faculty Research & Creative Works

A review of temperature-dependent magnetization data for nonsuperconducting PrBa2Cu4O8 and CmBa2Cu3O7 suggests that the failure of each to superconduct is related to the presence of Pr and Cm on their respective Ba sites. This defect is manifested, in each case, by short c-axis lattice parameters and anomalous high-temperature magnetic ordering which has been incorrectly attributed to ordering of the entire magnetic sublattice. Instead, it is shown that the anomalous high-temperature ordering as seen in the magnetization data is consistent with the ordering of magnetic ions substituted on the Ba site.

Block-By-Block Link-Path Analysis And Design With Physics-Based Models, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Link-path analysis and design by block can provide insight into performance and tighter performance budgeting.

A Comparison Of Alternating Minimization And Expectation Maximization Algorithms For Single Source Gamma Ray Tomography, R. Varma, S. Bhusarapu, J. A. O'Sullivan, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Lange and Carson (1984 J. Comput. Assist. Tomogr. 8 306-16) Defined Image Reconstruction for Transmission Tomography as a Maximum Likelihood Estimation Problem and Derived an Expectation Maximization (EM) Algorithm to Obtain the Maximum Likelihood Image Estimate. However, in the Maximization Step or M-Step of the EM Algorithm, an Approximation is Made in the Solution Which Can Affect the Image Quality, particularly in the Case of Domains with High Attenuating Material. O'Sullivan and Benac (2007 IEEE Trans. Med. Imaging 26 283-97) Reformulated the Maximum Likelihood Problem as a Double Minimization of an I-Divergence to Obtain a Family of Image Reconstruction Algorithms, …

Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim

Chemistry Faculty Research & Creative Works

There has been recent interest in conducting polymers that have very promising chemical and electrical applications. Some of these polymers have shown great potential for use in sensors.1 Polyaniline is one particular example of a prospective material. In our laboratory, we have studied the synthesis of polyaniline nanofibers. We have carried out one-pot syntheses to obtain polyaniline nanofibers in aqueous solutions where the polymerization was influenced by γ-radiation2 or UV-radiation.3 This polymer can also be patterned with an appropriate photo mask. In our present report, polyaniline nanofiber thin film sensors have been fabricated in one step by employing UV-irradiation and …

Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The physical properties of polymers at interfaces can be quite different from those in bulk due to the interaction between the absorbed polymer and the surface. This phenomenon can be probed through the dynamic behavior of the polymer chains at the interface which can be experimentally probed by techniques such as nuclear magnetic resonance spectroscopy (NMR),1 viscoelasticity, and calorimetry. At the polymer-air interface, polymer chains have more flexibility than those at the polymer-substrate interface. On the other hand, at the silica-polymer interface, where chains are more restricted on the surface, a higher glass transition temperature (Tg) results as compared with …

Dynamics Of Adsorbed Pma-D₃ - Effect Of Substrate, Frank D. Blum, Burak Metin, Macduff O. Okuom

Chemistry Faculty Research & Creative Works

In the last few years, our group has focused much of our attention on studying the dynamics of polymers adsorbed at interfaces. Much of our work, to date has been on labeled poly(vinyl acetate)-d3 (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3)2 on silica. We have been able to probe the effects of adsorbed amount,3 molecular mass,4,5 and the effect of overlayer.6 These studies have provided a view of the adsorbed polymer consistent with a motional gradient in the layer with the more mobile segments being those at the air-polymer interface and the less-mobile segments at the substratepolymer interface. However, we have not …

Discussion And Analysis Of Missile Igc Design, Michael W. Dancer, S. N. Balakrishnan, Ernest J. Ohlmeyer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Missile intercept systems used in the next generation missile defense system will require extremely accurate performance of all component systems. Such systems will need to guarantee successful intercept of highly maneuvering targets. as a result, such interceptor systems require much greater performance in its guidance, control, and estimation subsystems. in order to develop systems that meet the required accuracies, integrated guidance and control (IGC) systems are currently being studied. These IGC architectures infuse the guidance and control systems into a single framework thereby promoting natural synergy among the missile subsystems. Previous work in this area has relied on missile body-Based …

Micromachined Nanoporous Membranes For Blood Oxygenation Systems, Vijayakrishnan Ambravaneswaran, Susheil Uttamaraj, Zeynep Çelik-Butler, Robert C. Eberhart, Charles J. Chuong, Richard E. Billo, Michael A. Savitt

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nanostructured membranes with precisely engineered nanopores were fabricated on a thin silicon nitride membrane, using a combination of bulk micromachining and focused-ion-beam drilling. These membranes are designed to preserve microscale blood channel dimensions, thereby permitting the red cell shape change that enhances gas exchange in the pulmonary capillary. The membranes were tested for their mechanical stability and the results were verified with finite element analysis. Initial studies have proven the membranes to be robust, and capable of withstanding pressures typically experienced in blood oxygenator channels. A novel MEMS-based blood oxygenation system employing the nanoporous membranes is also presented. The oxygenation …

Texture Feature Selection For Buried Mine Detection In Airborne Multispectral Imagery, Spandan Tiwari, Sanjeev Agarwal, Anh Trang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a methodology for the detection of buried mines in airborne multispectral imagery is explored. the approach is based on utilizing the color texture information in the buried mine signatures, which is extracted using the cross-co-occurrence texture features. a systematic two-stage approach, using Bhattacharya Coefficient-Based analysis and principal feature analysis, is developed for the selection of a small subset of discriminatory features. Detection results from actual airborne data from two different sites are presented. the performances are compiled for four different feature-Based detectors and are compared with the conventional multiband RX anomaly detector, to validate the feature selection …

Dual-Polarized Near-Field Microwave Reflectometer For Noninvasive Inspection Of Carbon Fiber Reinforced Polymer-Strengthened Structures, Sergey Kharkovsky, Adam C. Ryley, Vivian Stephen, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Carbon fiber reinforced polymer (CFRP) composites are increasingly being used to strengthen various components of civil, aerospace, and automotive infrastructures. Subsequent to the application of CFRP, evaluation of the structural integrity of the strengthened members becomes a critical issue. Microwave noninvasive inspection techniques have been successfully used for this purpose. To this end, a novel near-field microwave inspection system that employs a dual-polarized reflectometer for detecting defects, such as disbonds between CFRP laminates and strengthened structures, was developed. It is shown that this system is capable of automatic removal of the influence of undesired standoff distance (or surface roughness) variations. …

Spatio-Spectral Sampling And Color Filter Array Design, Keigo Hirakawa, Patrick J. Wolfe

Electrical and Computer Engineering Faculty Publications

Owing to the growing ubiquity of digital image acquisition and display, several factors must be considered when developing systems to meet future color image processing needs, including improved quality, increased throughput, and greater cost-effectiveness. In consumer still-camera and video applications, color images are typically obtained via a spatial subsampling procedure implemented as a color filter array (CFA), a physical construction whereby only a single component of the color space is measured at each pixel location. Substantial work in both industry and academia has been dedicated to post-processing this acquired raw image data as part of the so-called image processing pipeline, …