Engineering Commons^™

Misfit: Mining Software Fault Information And Types, Billy R. Kidwell

Theses and Dissertations--Computer Science

As software becomes more important to society, the number, age, and complexity of systems grow. Software organizations require continuous process improvement to maintain the reliability, security, and quality of these software systems. Software organizations can utilize data from manual fault classification to meet their process improvement needs, but organizations lack the expertise or resources to implement them correctly.

This dissertation addresses the need for the automation of software fault classification. Validation results show that automated fault classification, as implemented in the MiSFIT tool, can group faults of similar nature. The resulting classifications result in good agreement for common software faults …

Multilevel Ant Colony Optimization To Solve Constrained Forest Transportation Planning Problems, Pengpeng Lin

Theses and Dissertations--Computer Science

In this dissertation, we focus on solving forest transportation planning related problems, including constraints that consider negative environmental impacts and multi-objective optimizations that provide forest managers and road planers alternatives for making informed decisions. Along this line of study, several multilevel techniques and mataheuristic algorithms have been developed and investigated. The forest transportation planning problem is a fixed-charge problem and known to be NP-hard. The general idea of utilizing multilevel approach is to solve the original problem of which the computational cost maybe prohibitive by using a set of increasingly smaller problems of which the computational cost is cheaper.

The …

Interfacial Bond Between Reinforcing Fibers And Calcium Sulfoaluminate Cements: Fiber Pullout Characteristics, Robert B. Jewell, Kamyar C. Mahboub, Thomas L. Robl, Arne C. Bathke

Civil Engineering Faculty Publications

The results of an experimental investigation on the influence of the interfacial bond of reinforcing fibers embedded in a calcium sulfoaluminate matrix on the fiber-pullout peak load and energy consumption are presented. Bonding at the fiber-matrix interface plays an important role in controlling the mechanical performance of cementitious composites—in particular, composites formed from sulfate-based systems (calcium sulfoaluminate [CSA] cements), as opposed to the silicate systems found in portland cement. Various types of fibers were selected, including polyvinyl alcohol (PVA), polypropylene, and copper-coated steel. The fibers were embedded in three different matrixes: two sulfate-based cements including one commercially available CSA cement …

Investigation Of Gate Dielectric Materials And Dielectric/Silicon Interfaces For Metal Oxide Semiconductor Devices, Lei Han

Theses and Dissertations--Electrical and Computer Engineering

The progress of the silicon-based complementary-metal-oxide-semiconductor (CMOS) technology is mainly contributed to the scaling of the individual component. After decades of development, the scaling trend is approaching to its limitation, and there is urgent needs for the innovations of the materials and structures of the MOS devices, in order to postpone the end of the scaling. Atomic layer deposition (ALD) provides precise control of the deposited thin film at the atomic scale, and has wide application not only in the MOS technology, but also in other nanostructures. In this dissertation, I study rapid thermal processing (RTP) treatment of thermally grown …

Fault Section Identification For Power Distribution Systems Using Online Measurements, Jie Chen

Theses and Dissertations--Electrical and Computer Engineering

Fault location is very important for distribution systems, and quickly identifying the fault and restoring the system can help reduce the outage time and make the system more reliable. In this thesis, a method for locating faults on distribution systems is introduced to quickly identify the faulted feeder sections by using the overcurrent information from the switches in the system. Fuzzy logic is utilized. The proposed method can quickly and accurately locate faulted sections with different fault locations, fault types and fault resistances. The method is applicable to cases with single-faults or multi-faults, and is applicable to networks with multi-sources. …

Hybrid Single And Dual Pattern Structured Light Illumination, Minghao Wang

Theses and Dissertations--Electrical and Computer Engineering

Structured Light Illumination is a widely used 3D shape measurement technique in non-contact surface scanning. Multi-pattern based Structured Light Illumination methods reconstruct 3-D surface with high accuracy, but are sensitive to object motion during the pattern projection and the speed of scanning process is relatively long. To reduce this sensitivity, single pattern techniques are developed to achieve a high speed scanning process, such as Composite Pattern (CP) and Modified Composite Pattern (MCP) technique. However, most of single patter techniques have a significant banding artifact and sacrifice the accuracy. We focus on developing SLI techniques can achieve both high speed, high …

A Methodology Of Spice Simulation To Extract Sram Setup And Hold Timing Parameters Based On Dff Delay Degradation, Xiaowei Zhang

Theses and Dissertations--Electrical and Computer Engineering

SRAM is a significant component in high speed computer design, which serves mainly as high speed storage elements like register files in microprocessors, or the interface like multiple-level caches between high speed processing elements and low speed peripherals. One method to design the SRAM is to use commercial memory compiler. Such compiler can generate different density/speed SRAM designs with single/dual/multiple ports to fulfill design purpose. There are discrepancy of the SRAM timing parameters between extracted layout netlist SPICE simulation vs. equation-based Liberty file (.lib) by a commercial memory compiler. This compiler takes spec values as its input and uses them …

Design Of Energy Storage Controls Using Genetic Algorithms For Stochastic Problems, Si Chen

Theses and Dissertations--Electrical and Computer Engineering

A successful power system in military applications (warship, aircraft, armored vehicle etc.) must operate acceptably under a wide range of conditions involving different loading configurations; it must maintain war fighting ability and recover quickly and stably after being damaged. The introduction of energy storage for the power system of an electric warship integrated engineering plant (IEP) may increase the availability and survivability of the electrical power under these conditions. Herein, the problem of energy storage control is addressed in terms of maximizing the average performance. A notional medium-voltage dc system is used as the system model in the study. A …

Pack Factor Measurements For Corn In Grain Storage Bins, Rumela Bhadra, Aaron P. Turner, Mark E. Casada, Michael D. Montross, Sidney A. Thompson, Josephine M. Boac, Samuel G. Mcneill, Ronaldo G. Maghirang

Biosystems and Agricultural Engineering Faculty Publications

Shelled yellow corn is commonly stored in concrete or corrugated steel bins. Granular materials compact under their own weight, primarily due to particle rearrangement, leading to an increase in bulk density and a change in volume when stored. Reliable grain pack factors are needed to estimate storage capacities and to accurately monitor grain inventories. A science-based model (WPACKING) of pack factors is available that uses the differential form of Janssen's equation and takes into account the variation in density caused by pressure variation with height and moisture content of the grain and accounts for the effects of grain type, test …

Stargrazer One: A New Architecture For Distributed Maximum Power Point Tracking Of Solar Photovoltaic Sources, Edgard Munoz-Coreas

Theses and Dissertations--Electrical and Computer Engineering

The yield from a solar photovoltaic (PV) source is dependent on factors such as light and temperature. A control system called a maximum power point tracker (MPPT) ensures that the yield from a solar PV source is maximized in spite of these factors. This thesis presents a novel implementation of a perturb and observe (PO) MPPT.

The implementation uses a switched capacitor step down converter and a custom digital circuit implementation of the PO algorithm. Working in tandem, the switched capacitor step down converter and the custom digital circuit implementation were able to successfully track the maximum power point of …

Nanostructured Semiconductor Device Design In Solar Cells, Hongmei Dang

Theses and Dissertations--Electrical and Computer Engineering

We demonstrate the use of embedded CdS nanowires in improving spectral transmission loss and the low mechanical and electrical robustness of planar CdS window layer and thus enhancing the quantum efficiency and the reliability of the CdS-CdTe solar cells. CdS nanowire window layer enables light transmission gain at 300nm-550nm. A nearly ideal spectral response of quantum efficiency at a wide spectrum range provides an evidence for improving light transmission in the window layer and enhancing absorption and carrier generation in absorber. Nanowire CdS/CdTe solar cells with Cu/graphite/silver paste as back contacts, on SnO₂/ITO-soda lime glass substrates, yield the …

Constrained Divergence-Conforming Basis Functions For Method Of Moments Discretizations In Electromagnetics, Robert Pfeiffer

Theses and Dissertations--Electrical and Computer Engineering

Higher-order basis functions are widely used to model currents and fields in numerical simulations of electromagnetics problems because of the greater accuracy and computational efficiency they can provide. Different problem formulations, such as method of moments (MoM) and the finite element method (FEM) require different constraints on basis functions for optimal performance, such as normal or tangential continuity between cells. In this thesis, a method of automatically generating bases that satisfy the desired basis constraints is applied to a MoM formulation for scattering problems using surface integral equations. Numerical results demonstrate the accuracy of this approach, and show good system …

Explorations For Efficient Reversible Barrel Shifters And Their Mappings In Qca Nanocomputing, Ke Chen

Theses and Dissertations--Electrical and Computer Engineering

This thesis is based on promising computing paradigm of reversible logic which generates unique outputs out of the inputs and. Reversible logic circuits maintain one-to-one mapping inside of the inputs and the outputs. Compared to the traditional irreversible computation, reversible logic circuit has the advantage that it successfully avoids the information loss during computations. Also, reversible logic is useful to design ultra-low-power nanocomputing circuits, circuits for quantum computing, and the nanocircuits that are testable in nature. Reversible computing circuits require the ancilla inputs and the garbage outputs. Ancilla input is the constant input in reversible circuits. Garbage output is the …

Multifrequency Averaging Of Hysteresis-Current-Controlled Dc-Dc Converters, Yingying Liu

Theses and Dissertations--Electrical and Computer Engineering

Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior as well as the ripple behavior of power electronic systems. Hysteresis current control has fast response and internal current stability through controlling switches to maintain the current within a given hysteresis band of a given current command. However the state space variables in a hysteresis controlled system cannot be directly approached by multifrequency averaging method because of time varing switching frequency. In this thesis, a method of applying multifrequency …

A New Islanding Detection Method Based On Wavelet-Transform And Ann For Inverter Assisted Distributed Generator, Zhengyuan Guan

Theses and Dissertations--Electrical and Computer Engineering

Nowadays islanding has become a big issue with the increasing use of distributed generators in power system. In order to effectively detect islanding after DG disconnects from main source, author first studied two passive islanding methods in this thesis: THD&VU method and wavelet-transform method. Compared with other passive methods, each of them has small non-detection zone, but both of them are based on the threshold limit, which is very hard to set. What’s more, when these two methods were applied to practical signals distorted with noise, they performed worse than anticipated.

Thus, a new composite intelligent based method is presented …

The Constrained Locally Corrected Nyström Method, Nastaran Hendijani

Theses and Dissertations--Electrical and Computer Engineering

In this dissertation a generalization of the locally corrected Nyström (LCN) discretization method is outlined wherein sparse transformations of the LCN system matrix are obtained via singular value decompositions of local constraint matrices. The local constraint matrices are used to impose normal continuity of the currents across boundaries shared by mesh elements. For this reason, the method is called constrained LCN (CLCN).

Due to the CLCN’s simplicity and flexibility, it is straightforward to develop high order CLCN systems for different formulations and mesh element types. As compared to the LCN, the CLCN method offers memory savings and improved accuracy when …

Average-Value Modeling Of Hysteresis Current Control In Power Electronics, Hanling Chen

Theses and Dissertations--Electrical and Computer Engineering

Hysteresis current control has been widely used in power electronics with the advantages of fast dynamic response under parameter, line and load variation and ensured stability. However, a main disadvantage of hysteresis current control is the uncertain and varying switching frequency which makes it difficult to form an average-value model. The changing switching frequency and unspecified switching duty cycle make conventional average-value models based on PWM control difficult to apply directly to converters that are controlled by hysteresis current control.

In this work, a new method for average-value modeling of hysteresis current control in boost converters, three-phase inverters, and brushless …

Compensation Methods For Demand Response, Zhaofeng Wang

Theses and Dissertations--Electrical and Computer Engineering

Recently, more and more disputations about how demand response should be compensated have arisen. Moreover, the court is about to rehear the Order 745. It probably will have significant impact on the whole working system used to be built for demand response before. Nowadays, some power companies and utilities think that they will endure profits leakage while demand response resources still are compensated.

In this research, knowledge of demand response, local marginal price, Order 745 and other related concept will be explained in detail in case of misunderstanding. Associated with all these knowledge, a possible compensation method will be proposed. …

Biomolecule Localization And Surface Engineering Within Size Tunable Nanoporous Silica Particles, Daniel M. Schlipf

Theses and Dissertations--Chemical and Materials Engineering

Mesoporous silica materials are versatile platforms for biological catalysis, isolation of small molecules for detection and separation applications. The design of mesoporous silica supports for tailored protein and biomolecule interactions has been limited by the techniques to demonstrate biomolecule location and functionality as a function of pore size. This work examines the interaction of proteins and lipid bilayers with engineered porous silica surfaces using spherical silica particles with tunable pore diameters (3 – 12 nm) in the range relevant to biomolecule uptake in the pores, and large particle sizes (5 - 15 µm) amenable to microscopy imaging

The differentiation of …

Nanomechanical And Scaling Behavior Of Nanoporous Gold, Nicolas J. Briot

Theses and Dissertations--Chemical and Materials Engineering

Nanoporous metals have recently been drawn significant interest in various fields of research. Their high surface-to-volume ratio present a strong potential for applications in sensing, catalysis, micro-electromechanical systems (MEMS) and even in the medical field. However, the mechanical properties of nanoporous metals have not yet been well determined, as conducting mechanical tests was found to be challenging. Scaling relations linking the mechanical properties of porous materials to those of their dense counterparts are successfully and widely used for many porous metals. However, their applicability to nanoporous metals have recently been questioned, as estimations from the classic scaling relations were found …

Nanoindentation Of A Zinc Metal Soap Mixture For Use In A Laser Printer, George A. Nimick

Theses and Dissertations--Chemical and Materials Engineering

At the start of this project, the possible choices of metal soaps had already been narrowed to include some of the zinc soaps used in this project. These zinc soaps are mixtures of zinc stearate and zinc palmitate of varying ratios purchased from a supplier. Zinc soap was chosen as result of its common use in various industries as a lubricant and mold release, which implied potential benefits in an electrophotographic printing system. These potential benefits include, but are not limited to, a more efficient transfer from a photoconductive drum and protection of the drum from mechanical and chemical degradation. …

Fundamental Studies Of Surfactant Templated Metal Oxide Materials Synthesis And Transformation For Adsorption And Energy Applications, Saikat Das

Theses and Dissertations--Chemical and Materials Engineering

This work addresses fundamental aspects of designing templates and curing conditions for the synthesis of mesoporous metal oxide thin films. The first section addresses selection of cationic-carbohydrate surfactant mixtures to synthesize templated silica thin films for selective adsorption of simple carbohydrates based on molecular imprinting. Nuclear magnetic resonance and fluorescence spectroscopy results suggest a novel structure for mixtures of alkyl glucopyranosides or xylopyranosides with cationic (trimethylammonium) surfactants. Despite thermodynamically favorable mixing, the carbohydrate headgroups in the mixed micelle adopt an inverted configuration with their headgroups in the micelle core, and therefore are inaccessible for molecular imprinting. This orientation occurs even …

Engineered Surface Properties Of Porous Tungsten From Cryogenic Machining, Julius M. Schoop

Theses and Dissertations--Chemical and Materials Engineering

Porous tungsten is used to manufacture dispenser cathodes due to it refractory properties. Surface porosity is critical to functional performance of dispenser cathodes because it allows for an impregnated ceramic compound to migrate to the emitting surface, lowering its work function. Likewise, surface roughness is important because it is necessary to ensure uniform wetting of the molten impregnate during high temperature service. Current industry practice to achieve surface roughness and surface porosity requirements involves the use of a plastic infiltrant during machining. After machining, the infiltrant is baked and the cathode pellet is impregnated. In this context, cryogenic machining is …

Microindentation Of Bi57in26sn17 Lead-Free Alloy, Ruiting Zhao

Theses and Dissertations--Chemical and Materials Engineering

There is great need to understand the mechanical properties of lead-free alloys—an alternative of lead-based alloys—to address the environmental problems associated with the use of lead-based materials in microelectronics. In this work, the microstructures of Bi57In26Sn17 lead-free alloy were examined using Optical Microscopy and Energy Dispersive X-ray Spectroscopy analysis. The micro-indentation technique was used to study the mechanical properties of Bi57In26Sn17 lead-free alloy. The experimental results of the hardness and contact modulus were presented and discussed. Local creep during the indentation was observed from the load-displacement curves. The Vickers hardness (HV) increases with the decrease of the indentation depth, suggesting …

Synthesis, Structure, Properties And Applications Of Nanoporous Silicon And Palladium, Xu Jiang

Theses and Dissertations--Chemical and Materials Engineering

Nanoporous (np) materials with pore size below 100 nano-meters exist naturally in biological and mineral structures, and synthetic np materials have been used industrially for centuries. Np materials have attracted significant research interest in recent decades, as the development of new characterization techniques and nanotechnology allow the observation and design of np materials at a new level. This study focuses on two np materials: nanoporous silicon (np-Si) and nanoporous palladium (np-Pd).

Silicon (Si), because of its high capacity to store lithium (Li), is increasingly becoming an attractive candidate as anode material for Li ion batteries (LIB). One significant problem with …

Interfacial Engineering Of Biomass Hydrolysis By Cellulase Enzymes And Mechanistic Modeling Of Hydrolysis Of Cellulose Substrates, Ravinder Kumar Garlapalli

Theses and Dissertations--Chemical and Materials Engineering

Lignocellulosic biomass is a sustainable and renewable energy resource that can be converted to fuels and other commodity chemicals, but this conversion is currently limited by its recalcitrance to enzymatic degradation. Because of this recalcitrance, the major challenges in the commercialization of enzymatic hydrolysis processes are the relatively low hydrolysis rates, limited cellulose conversion under some conditions, and high cost of enzymes.

Enzymatic hydrolysis is influenced by the structure of the biomass after pretreatment and the mode of enzyme action, but has also been shown to be enhanced by surfactant additives. The objective of this work was to elucidate the …

Evaporation-Induced Formation Of Well-Ordered Surface Patterns On Polymer Films, Wei Sun

Theses and Dissertations--Chemical and Materials Engineering

Various techniques of fabricating surface patterns of small scales have been widely studied due to the potential applications of surface patterns in a variety of areas. It is a challenge to fabricate well-ordered surface area efficiently and economically. Evaporation-induced surface patterning is a promising approach to fabricate well-ordered surface patterns over a large area at low cost. In this study, the evaporation-induced surface patterns with controllable geometrical characteristics have been constructed. The dewetting kinetics on deformable substrate is also investigated.

Using simple templates to control the geometry and the evaporation behavior of a droplet of volatile solvent, various gradient surface …

Determining The Effects Of Cd151 And Β1 On Tumor Cell Adhesion And Migration, Rachel R. Essex

Theses and Dissertations--Chemical and Materials Engineering

Previous studies have shown that the upregulation of CD151 and β₁ is associated with poor prognosis in many cancers such as breast cancer. Studies have provided evidence that these proteins are associated with the adhesion and migration of tumor cells. In this study, a microfluidic flow chamber was utilized to determine how CD151 and β₁ affected the firm and initial adhesion of metastatic breast cancer cells to a planar endothelial monolayer under shear stress. This system mimicked the adhesion of metastatic breast cancer cells to the endothelial cells of the circulatory system. CD151 and β₁ increased the …

Interfacial Polymerization For Colorimetric Labeling Of Protein Expression In Cells, Jacob L. Lilly, Phillip R. Sheldon, Liv J. Hoversten, Gabriela Romero, Vivek Balasubramaniam, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

Determining the location of rare proteins in cells typically requires the use of on-sample amplification. Antibody based recognition and enzymatic amplification is used to produce large amounts of visible label at the site of protein expression, but these techniques suffer from the presence of nonspecific reactivity in the biological sample and from poor spatial control over the label. Polymerization based amplification is a recently developed alternative means of creating an on-sample amplification for fluorescence applications, while not suffering from endogenous labels or loss of signal localization. This manuscript builds upon polymerization based amplification by developing a stable, archivable, and colorimetric …

First Proof Of Concept Of Sustainable Metabolite Production From High Solids Fermentation Of Lignocellulosic Biomass Using A Bacterial Co-Culture And Cycling Flush System, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

To improve the lignocellulose conversion for ABE in high solids fermentation, this study explored the feasibility of cycling the process through the cellulolytic or/and solventogenic phases via intermittent flushing of the fermentation media. Five different flushing strategies (varying medium ingredients, inoculum supplement and cycling through phases) were investigated. Flushing regularly throughout the cellulolytic phase is necessary because re-incubation at 65 °C significantly improved glucose availability by at least 6-fold. The solvents accumulation was increased by 4-fold using corn stover (3-fold using miscanthus) over that produced by flushing only through the solventogenic phase. In addition, cycling process was simplified by re-incubating …