Digital Commons Network^™

Casat-Hoomt: Computer Aided Software Analysis Tool Based On High Order Object-Oriented Modeling Technique, Fan Zhang, Jinwu Wang, Xiaoqing Frank Liu, Buqing Cao, Mingdong Tang

Computer Science Faculty Research & Creative Works

This paper presents the first computer aided software analysis tool based on HOOMT (High Order Object-oriented Modeling Technique), which provides facilities for structured object-oriented analysis by integrating structured analysis and object-oriented analysis. It contains a graphical user interface for HOOMT-based modeling, supports modeling information management, and provides functionalities for developing three component sub-models in HOOMT: High Order Object Model (HOOM), Hierarchical Object Information Flow Model (HOIFM), and Hierarchical State Transition Model (HSTM). It supports structured decomposition of high-order objects, processes, and states. We describe its system architecture and implementation in this paper. © 2013 IEEE.

Consensus Protocols In Networked Multiagent Systems For Cluttered And Hostile Environments, Gerardo De La Torre, Eric N. Johnson, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Consensus refers to the agreement of networked agents upon certain quantities of interest and has widespread applications in diverse areas in science and engineering. This paper focuses on a new consensus protocol for networked multiagent systems operating in cluttered and hostile environments. Specifically, a consensus optimization algorithm is introduced that renders the Laplacian potential to be a nonincreasing function while minimizing a cost function and satisfying state and cost constraints. In addition, we show how to choose this cost function and the aforementioned constraints in order to decay the Laplacian potential to zero strictly. The proposed framework depends on a …

Magneto-Electric Dipole Antenna Based On Differentially-Excited Composite Right/Left-Handed (Crlh) Transmission Lines, S. Gupta, Lijun Jiang, C. Caloz

Electrical and Computer Engineering Faculty Research & Creative Works

A new magneto-electric (ME) dipole antenna array is proposed which provides a combined electric- and magnetic-dipole response in a planar configuration. The proposed structure is based on Composite Right/Left-Handed (CRLH) transmission lines, which is differentially fed and operated in the zeroth-order regime to provide maximal gain for the combined radiators. The basic principle of the proposed ME-dipole antenna is discussed and demonstrated with full-wave simulation results. © 2013 IEEE.

Integration Of Arbitrary Lumped Multiport Circuit Networks Into The Discontinuous Galerkin Time-Domain Analysis, Ping Li, Li Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A hybrid electromagnetic (EM) circuit simulator is proposed for incorporating multiport lumped circuit networks through their admittance matrices into the discontinuous Galerkin time-domain (DGTD) method. The admittance matrix in the Laplace domain can be derived analytically or obtained from network parameters such as -parameters in the frequency domain. To convert frequency-dependent -parameters into the admittance matrix in the Laplace domain, the vector-fitting technique is employed to facilitate the mapping process. The computational domain of interest is split into two subdomains. One is the EM part solved by the DGTD, and another is the circuit part modeled by the basic I-V …

Enhanced-Resolution Folded C-Section Phaser, S. Gupta, Lijun Jiang, C. Caloz

Electrical and Computer Engineering Faculty Research & Creative Works

A new C-section phasers based on folded coupled-line couplers has been proposed for high-resolution analog signal processing (ASP). The folded configuration of the coupled-line coupler provides a tight coupling in a planar configuration between the input and the coupled port, using sections of relatively small coupling values. It subsequently provides a larger group delay swing in the corresponding C-section phaser required for enhanced resolution ASP. The proposed phaser is demonstrated using full-wave simulations. © 2013 IEEE.

Pulsed Line Source Response Of A Thin Sheet With High-Contrast Dielectric And Conductive Properties - A Time-Domain Analysis, Adrianus T. De Hoop, Ling Ling Meng, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A methodology is presented for analytically modeling the reflection and transmission of line-source excited pulsed electromagnetic fields at a thin, planar layer with high-contrast dielectric and conductive properties. Closed-form analytic time-domain expressions are derived for the field components in a 2-D setting via an extension of the Cagniard-DeHoop method. The response to the power exponential source and the power exponential monocycle pulse were studied using the newly proposed method. © 2013 IEEE.

A New Efie Method Based On Coulomb Gauge For The Low-Frequency Electromagnetic Analysis, Xiaoyan Y.Z. Xiong, Li (Lijun) Jun Jiang, Wei E.I. Sha, Yat Hei Lo

Electrical and Computer Engineering Faculty Research & Creative Works

To solve the low-frequency breakdown inherent from the electric field integral equation (EFIE), an alternative new form of the EFIE is proposed by using the Coulomb-gauge Green's function of quasi-static approximation. Di®erent from the commonly adopted Lorentz-gauge EFIE, the Coulomb-gauge EFIE separates the solenoidal and irrotational surface currents explicitly, which captures inductive and capacitive responses through electrodynamic and electrostatic Green's functions, respectively. By applying existing techniques such as the loop-tree decomposition, frequency normalization, and basis rearrangement, the Coulomb-gauge EFIE also can remedy the low-frequency breakdown problem. Through comparative studies between the Lorentz-gauge and Coulomb-gauge EFIE approaches from mathematical, physical and …

The Numerical Steepest Descent Path Method For Calculating Physical Optics Integrals On Smooth Conducting Quadratic Surfaces, Yu Mao Wu, Li (Lijun) Jun Jiang, Wei E.I. Sha, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we use the numerical steepest descent path (NSDP) method to analyze the highly oscillatory physical optics (PO) integral on smooth conducting parabolic surfaces, including both monostatic and bistatic cases. Quadratic variations of the amplitude and phase functions are used to approximate the integrand of PO integral. Then the surface PO integral is reduced into several highly oscillatory line integrals. By invoking the NSDP method, these highly oscillatory PO line integrals are defined on the corresponding NSDPs. Furthermore, the critical point contributions for the PO integral are exactly extracted and represented based on the NSDPs. The proposed NSDP …

A Systematic Electromagnetic-Circuit Method For Emi Analysis Of Coupled Interconnects On Dispersive Dielectrics, Min Tang, Jiaqing Lu, Junfa Mao, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a systematic electromagnetic-circuit method for efficient simulation of coupled interconnects on dispersive dielectrics in the presence of electromagnetic interference. The dispersive substrate of coupled interconnects is characterized by the multiterm Debye or Lorentz formula. According to the differential equations derived from the equivalent circuit modeling of dispersive media, the full-wave finite-difference time-domain algorithm is utilized to capture accurate field in a dispersive substrate. The effects of incident field, under the quasi-TEM assumption, are then represented by the distributed sources along transmission lines. An efficient algorithm based on the waveform relaxation with transverse partitioning (WR-TP) is employed for …

Skin-Effect Loss Models For Time- And Frequency-Domain Peec Solver, Albert E. Ruehli, Giulio Antonini, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A challenging and interesting issue for the solution of large electromagnetic problems is the efficient, sufficiently accurate modeling of the broadband skin-effect loss for conducting planes and 3-D shapes. The inclusion of such models in an electromagnetic (EM) solver can be very costly in compute time and memory requirements. These issues are particularly important for the class of signal, power, and noise integrity (NI) problems. In this paper, we concentrate on partial element equivalent circuit (PEEC)-type methods which are suitable for the solution of this class of problems. Progress has been made recently in the design of skin-effect models. The …

Overview Of Large-Scale Computing: The Past, The Present, And The Future, Weng Cho Chew, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This is a brief review of the development of computational electromagnetics (CEM) to partially summarize its achievements, issues, and possibilities. © 1963-2012 IEEE.

Finite-Width Feed And Load Models, Yat Hei Lo, Li (Lijun) Jun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

We demonstrate a new method of applying the feed model for the method of moments (MoM) formulation for the electric field integral equation (EFIE). The model is based around a previously reported magnetic ribbon current model which is accurate and allows for a finite width of the feed port. However, with proper approximations, one can reduce the formulation such that the magnetic field operator can be removed in order to simplify computations arising from the curl of the dyadic Green's function and its singularities. We show here that the new feed model can also be used to model a lumped …

An Iterative Source Reconstruction Method Exploiting Phaseless Electric Field Data, Ping Li, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional equivalent source reconstruction methods (SRM) require both phase and amplitude information of the acquired field data. However, there are situations where the phase information is not available or impractical to obtain. Hence, the development of SRM using phaseless fields is important. In this paper, a novel iterative SRM based on phaseless electric fields is presented. The reconstructed equivalent current source can be electric, magnetic current, or both. They can fit the physical geometry of the radiator. Electric field integral equation (EFIE) is employed to build the relationship between the reconstructed current source and measured fields. It can precisely reproduce …

Method And Apparatus For Adaptive Scatter Correction, Xin Liu, J. Hsieh, X. Wu

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

A CT system includes a rotatable gantry having an opening to receive an object to be scanned, an x-ray source configured to project an x-ray beam toward the object having a primary intensity, a detector configured to detect high frequency electromagnetic energy passing through the object and output imaging data, and a data acquisition system (DAS) connected to the detector and configured to receive the imaging data. The system also includes a computer programmed to obtain image projection data of the object from the DAS, correct the projection data using a scatter function that is based at least on a …

Model Based Fault Diagnosis And Prognosis Of Nonlinear Systems, Hasan Ferdowsi

Doctoral Dissertations

"Rapid technological advances have led to more and more complex industrial systems with significantly higher risk of failures. Therefore, in this dissertation, a model-based fault diagnosis and prognosis framework has been developed for fast and reliable detection of faults and prediction of failures in nonlinear systems. In the first paper, a unified model-based fault diagnosis scheme capable of detecting both additive system faults and multiplicative actuator faults, as well as approximating the fault dynamics, performing fault type determination and time-to-failure determination, is designed. Stability of the observer and online approximator is guaranteed via an adaptive update law. Since outliers can …

Manufacturing And Characterization Of Polyurethane Based Sandwich Composites, Stephen Robert Hawkins

Masters Theses

"Composite sandwich structures have been extensively employed in aerospace structures, ship building, infrastructure, etc. due to their light weight and high strength to weight ratio. The understanding of their behavior under impact and environmental conditions is extremely important for the design and manufacturing of these engineering structures since these problems are directly related to structural integrity and safety requirements. Vacuum assisted resin transfer molding (VARTM) is one of the commonly used low cost composite manufacturing processes. Polyurethane (PU) resin system has been observed to have better mechanical properties and higher impact strength when compared to conventional resin systems such as …

Predicting Solar Radiation Based On Available Weather Indicators, Frank Joseph Sauer

Masters Theses

"Solar radiation prediction models are complex and require software that is not available for the household investor. The processing power within a normal desktop or laptop computer is sufficient to calculate similar models. This barrier to entry for the average consumer can be fixed by a model simple enough to be calculated by hand if necessary.

Solar radiation modeling has been historically difficult to predict and accurate models have significant assumptions and restrictions on their use. Previous methods have been limited to linear relationships, location restrictions, or input data limits to one atmospheric condition. This research takes a novel approach …

Feature Extraction Through K-Means Segmentation For Melanoma Detection, Snigdha Priya Bommadevara

Masters Theses

"Malignant melanoma is responsible for 75% of the deaths caused due to skin cancer annually. However, melanoma detection can be possible through feature extraction and pattern classification, which can lower the risk, if the melanoma is detected at an early stage. Clustering is one of the most useful tools used to differentiate features that can contribute to melanoma. This research work uses the k-means clustering algorithm for implementation of color segmentation. However, k-means clustering requires a predefined value of k, i.e., the number of clusters must be specified at the beginning of the run. This research uses a predefined value …

Technical Modeling And Control System Development Of Hybrid Energy System Using Coal, Nuclear, Wind And Diesel, Uday Guntupalli

Masters Theses

"Addressing the growing energy concerns of the modern world is a challenging problem. Traditional carbon intensive fuel sources like coal, diesel which are instrumental in meeting today's grid demand are struggling to meet the stringent environmental regulations. Operations of independent renewable energy sources despite reducing costs are not comparable to existing costs of electricity. A sustainable approach to address these concerns is proposed in this work. A hypothetical hybrid system involving traditional fuel sources like coal, small modular nuclear reactor and renewable energy source wind is analyzed through dynamic modeling using various tools.

Various simulation tools were analyzed and the …

Fuzzy Logic Color Detection: Blue Areas In Dermoscopy Melanoma Images, Mounika Lingala

Masters Theses

"Malignant melanoma is one of the deadliest forms of skin cancer and is one of the most rapidly increasing cancers in the world. Image analysis techniques for the early detection of melanoma are dependent upon the detection of multiple color shades in melanoma images. Use of magnified visible-light imaging by dermoscopy allows detailed investigation of these color shades. This research explores the fuzzy logic methods for the detection and characterization of blue color shades to discriminate melanoma from benign skin lesions. Standard thresholds are placed on the RGB dermoscopy images firstly and then the restrictiveness is explored by implementing fuzzy …

Development Of A New Temporary Fastener For Aerospace Automation, Xiangwen Zhang

Masters Theses

"Temporary fasteners are required in aircraft assembly, especially in the assembly of wings, fuselage, and aircraft skin's substructure prior to drilling holes for permanent fasteners by automated drilling machines. The objective was to develop a temporary fastener that can be installed, clamped, loosened, and removed from one side with a short head length. Published papers, web pages and patents relating to temporary fasteners were reviewed. Then by considering the ability to meet the operation requirements and concerns, a temporary fastener was designed with the following advantages:

• a simple structure that can be easily fabricated
• a short head length to save …

Manufacturing And Performance Evaluation Of Out-Of-Autoclave Sandwich Composites, Sriram Nagarajan

Masters Theses

"Composite sandwich structures are being increasingly employed in applications which require high strength, high in-plane and flexural stiffness coupled with a reduction in weight. Sandwich composites used in the aerospace industry are typically manufactured using high pressure autoclave processing which is expensive and time consuming. A viable low cost alternative is the Out-of-autoclave (OOA) process. One of the most dominant failure modes in sandwich composites is the debonding that occurs at the facesheet skin to core interphase leading to severe degradation of structural properties of the sandwich. A well formed adhesive bond at the skin to core interphase and improved …

Monitoring Micropile Foundations Of Bridge During Construction, Devin Tavis Dixon

Masters Theses

"Information regarding the load transfer of micropiles during in-service construction has virtually never been monitored or documented. The primary objective of this research project was to monitor the load transfer versus the depth of production micropiles during construction. The micropiles being studied were used to support Bridge No. 2 of the Foothills Parkway in eastern Tennessee during construction. Two of the piers (1 & 2) were instrumented for the purpose of this study. Vibrating wire strain gages (VWSG) were installed on select micropiles within pile groups of twenty (20) micropiles. Seven vibrating wire strain gages were installed on each micropile …

Statistical Analysis Of Microarray Data In Sleep Deprivation, Stephanie Marie Berhorst

Masters Theses

"Microarray technology is a useful tool for studying the expression levels of thousands of genes or exons within a single experiment. Data from microarray experiments present many challenges for researchers since costly resources often limit the experimenter to small sample sizes and large amounts of data are generated. The researcher must carefully consider the appropriate statistical analysis to use that aligns with the experimental design employed. In this work, statistical issues are investigated and addressed for a microarray experiment that examines how expression levels change over time as individuals are sleep deprived. Over the course of 48 hours of sleep …

Systems And Image Database Resources For Uav Search And Rescue Applications, David Christopher Macke Jr.

Masters Theses

"Aerial search and rescue applications using unmanned aerial vehicles (UAVs) can incorporate image processing technologies to locate targets faster and with a higher degree of accuracy. The task of developing such systems involves the development of both hardware and software components. Examples of both hardware and software approaches in the design process for an aerial imaging system are shown for small UAV applications. This project contains resources to help facilitate the incorporation of UAV applications into educational ventures and design projects. A power supply design is done for a lightweight imaging system and a large database of aerial images is …

Part I: Increased Leaching Of Arsenic, Selenium, Molybdenum, And Vanadium From High Calcium Coal Ash Containing Trona Reaction Products. Part Ii: Using Agricultural Byproduct Rice Hull As Biosorbent To Remove And Recover Metal Ions In Water, Yongbo Dan

Masters Theses

"Part I. The trona is being injected to control SO_x emission from coal-fired power plants. The results showed that trona ash leached significantly more As, Se, Mo, and V than the control fly ash did, especially under the natural pH condition. In addition, trona ash had a significantly greater soluble fraction than the control ash. Further investigation indicated that greater amounts of the studied anionic elements in the trona ash were associated with the soluble, trona reaction products. Moreover, the insoluble fraction of the trona ash lost its capability to adsorb these elements under the natural pH condition. The …

Balanced Cross Section Of The Northeast Of Adiyaman, Turkey, Mustafa Tuncer

Masters Theses

"Deformation during closure of an ocean basin and continent-continent collision in southeast Anatolia Turkey during the Late Cretaceous to Middle Miocene was investigated by construction of a geologic map, structural cross-section and retrodeformed palinspastically restored cross-section. The area of study is a N-S transect across the Bitlis Suture Zone of Northeast of Adiyaman. The study area is situated in the southeast Anatolian orogenic belt which includes, from south to north, the Arabian platform, the zone of Imbrication, and the zone of Nappes. A geologic map of this region was prepared in order to construct balanced and restored cross sections from …

Effects Of Initial Conditions On Rayleigh-Taylor Instability Using Elastic-Plastic Materials, Pamela Susan Roach

Masters Theses

"When an elastic-plastic solid is accelerated by a fluid of lower density, Rayleigh-Taylor instability (RTI) is observed, and the instability is mitigated by the material's mechanical strength, initial conditions, and the acceleration that drives the instability. Such instances of RTI are observed in supernovas, explosive welding, and inertial confinement fusion. In contrast to Newtonian fluids, experimental study of RTI in accelerated solids is traditionally hindered by difficulty to measure material properties and exceedingly small time scales. An understanding of the role initial conditions and material properties have on the growth of RTI will lead to better control of the instability. …

Fluidic Sensor Devices Utilizing Dry Film Resist As Main Structural Materials, Sijia Gong

Masters Theses

"In this thesis, two types of fluidic sensor devices are demonstrated. The first device utilizes a dry film resist (DFR) as the main structural material of fluidic device utilizing the photolithography process. The second one involves a simple, low-cost sensor platform composed of ubiquitous materials such as polymer tubing and metal wires. Both devices are prepared to measure the dissolved oxygen content, as a model target analyte, based on the oxygen quenching reaction of a ruthenium complex fluorophore as the reporting agent. Characterization of sensors is conducted based on the fluorescence lifetime measurement. The first type of sensor is constructed …

Feature Extraction Through Median-Split Algorithm Segmentation For Melanoma Detection, Venkata Sai Narasimha Kaushik Ghantasala

Masters Theses

""Detection of melanoma remains an empirical clinical science. New tools for automatic discrimination of melanoma from benign lesions in digitized dermoscopy images may allow an improvement in early detection of melanoma. This research implements a fast version of the median split algorithm in an open source format and applied to four-color splitting of the lesion area to capture the architectural disorder apparent in melanoma colors. This version of the median split algorithm splits colors along the color axis with maximum range". For a dermoscopy set of 888 images, K-means clustering algorithm is compared with a median split algorithm to find …