Engineering Commons^™

Reliability Models For Hpc Applications And A Cloud Economic Model, Thanadech Thanakornworakij

Doctoral Dissertations

With the enormous number of computing resources in HPC and Cloud systems, failures become a major concern. Therefore, failure behaviors such as reliability, failure rate, and mean time to failure need to be understood to manage such a large system efficiently.

This dissertation makes three major contributions in HPC and Cloud studies. First, a reliability model with correlated failures in a k-node system for HPC applications is studied. This model is extended to improve accuracy by accounting for failure correlation. Marshall-Olkin Multivariate Weibull distribution is improved by excess life, conditional Weibull, to better estimate system reliability. Also, the univariate …

Nanowire Giant Magnetoresistance Thin Films For Magnetic Sensors, Bryan Cox

Doctoral Dissertations

This dissertation details a novel method to fabricate magnetic sensors using nanowire giant magnetoresistance (GMR) thin films. In 1988, Albert Fert and Peter Grünberg both independently discovered a new physical phenomenon called GMR. GMR is a quantum mechanical effect found in thin film materials that are composed of alternating nanoscale ferromagnetic and non-magnetic conductive layers. When a GMR material is in the presence of a magnetic field, a change in electrical resistance is observed. The GMR effect has been utilized to produce magnetic sensors that have been used in a variety of applications, such as computer hard drive read heads, …

A Nanostructured Fabry-Perot Interferometer For Label-Free Biodetection, Tianhua Zhang

Doctoral Dissertations

A polymer nanostructured Fabry-Perot interferometer (FPI) based biosensor has been developed, fabricated, and tested. Different from a conventional FPI, this nanostructured FPI has a layer of Au-coated nanopores inside its cavity. The Au-coated nanostructure layer offers significant enhancement of optical transducing signals due to the localized surface Plasmon resonance (L-SPR) effect. Compared to a traditional FPI for label-free biosensing applications, the polymer nanostructured FPI based biosensor offers increased sensing surface area, extended penetration depth of the excitation light, and amplification of optical transducing signals. Using a nanostructured FPI, measurements taken had great improvements in free spectral range (FSR), finesse, and …

Numerical Simulation Of Nanopulse Penetration Of Biological Matter Using The Adi-Fdtd Method, Fei Zhu

Doctoral Dissertations

Nanopulses are ultra-wide-band (UWB) electromagnetic pulses with pulse duration of only a few nanoseconds and electric field amplitudes greater than 105 V/m. They have been widely used in the development of new technologies in the field of medicine. Therefore, the study of the nanopulse bioeffects is important to ensure the appropriate application with nanopulses in biomedical and biotechnological settings. The conventional finite-difference time-domain (FDTD) method for solving Maxwell's equations has been proven to be an effective method to solve the problems related to electromagnetism. However, its application is restricted by the Courant, Friedrichs, and Lewy (CFL) stability condition that confines …

Basic Capillary Microfluidic Chip And Highly Sensitive Optical Detector For Point Of Care Application, Mingjin Yao

Doctoral Dissertations

A cost-effective and highly sensitive portable diagnostic device is needed to enable much more widespread monitoring of health conditions in disease prevention, detection, and control. Miniaturized and easy-to-operate devices can reduce the inherent costs and inefficiencies associated with healthcare testing in central laboratories. Hence, clinicians are beginning to use point of care (POC) testing and flexible clinical chemistry testing devices which are beneficial for the patient.

In our work, a low-cost and simple autonomous microfluidic device for biochemical detection was developed. The pumpless capillary system with capillary stop valves and trigger valves is fabricated on a silicon (Si) wafer and …

Mathematical Modeling Of Pipeline Features For Robotic Inspection, Yang Gao

Doctoral Dissertations

Underground pipeline systems play an indispensable role in transporting liquids in both developed and developing countries. The associated social and economic cost to repair a pipe upon abrupt failure is often unacceptable. Regular inspection is a preventative action that aims to monitor pipe conditions, catch abnormalities and reduce the chance of undesirable surprises. Robots with CCTV video cameras have been used for decades to inspect pipelines, yielding only qualitative information. It is becoming necessary and preferable for municipalities, project managers and engineers to also quantify the 3-D geometry of underground pipe networks. Existing robots equipped specialized hardware and software algorithms …

Fabrication And Characterization Of Hybrid Energy Harvesting Microdevices, Zhongcheng Gong

Doctoral Dissertations

In this dissertation, a hybrid energy harvesting system based on a lead zirconate titanate (PZT) and carbon nanotube film (CNF) cantilever structure has been designed, fabricated and studied. It has the ability to harvest light and thermal radiation energy from ambient energy and convert them to electricity.

The proposed micro-scale energy harvesting device consists of a composite cantilever beam (SU-8/CNF/Pt/PZT/Pt) which is fixed on a silicon based anchor and two electrode pads for wire bonding. The CNF acts as an antenna to receive radiation energy and convert it to heat energy and then transfer to the whole cantilever structure. The …

The Engineering Design Process As A Model For Stem Curriculum Design, Krystal Sno Corbett

Doctoral Dissertations

Engaging pedagogics have been proven to be effective in the promotion of deep learning for science, technology, engineering, and mathematics (STEM) students. In many cases, academic institutions have shown a desire to improve education by implementing more engaging techniques in the classroom. The research framework established in this dissertation has been governed by the axiom that students should obtain a deep understanding of fundamental topics while being motivated to learn through engaging techniques. This research lays a foundation for future analysis and modeling of the curriculum design process where specific educational research questions can be considered using standard techniques. Further, …

The Search For An Optimal Means Of Determining The Minmax Control Parameter Using Sensitivity Analysis, John Teye Brown

Doctoral Dissertations

The use of computational methods for design and simulation of control systems allows for a cost-effective trial and error approach. In this work, we are concerned with the robust, real-time control of physical systems whose state space is infinite-dimensional. Such systems are known as Distributed Parameter Systems (DPS). A body whose state is heterogeneous is a distributed parameter. In particular, this work focuses on DPS systems that are governed by linear Partial Differential Equations, such as the heat equation. We specifically focus on the MinMax controller, which is regarded as being a very robust controller. The mathematical formulation of the …

Surface Expressions Of Discontinuities, And The Estimation Of Their 3-D Orientations Using Combined Lidar And Optical Imaging, James Nii Aboh Otoo

Doctoral Dissertations

"The importance of the collection and analysis of data on discontinuities cannot be overemphasized. Problems which include sampling difficulties, risks, limited access to rock faces and exposures, and the delay in data collection has led to a high need for data collection tools and analysis techniques that can overcome these problems.

Discontinuities manifest themselves as either traces or as facets. Traces are linear features that intersect with both the discontinuity and the rock cut. Facets are the actual discontinuity surfaces that are exposed in the rock cut. Facets can be natural or induced. Identifying a facet as either natural or …

Modeling And Synthesis Of Pvdf-Based Dielectrics For Energy Storage Applications, Xuhui Lu

Doctoral Dissertations

"The purpose of this research was to develop dielectric films for high energy density capacitor applications. Also desired was to develop a deeper understanding of dielectric breakdown and electric energy storage related phenomena through simulation, theoretical analysis, and experimental investigation.

An analytical model incorporating Weibull dielectric strength statistics was developed to establish quantitative relationships between material properties and device performance of self-healing capacitors. The model is useful for designing high voltage capacitors and developing dielectric materials where the effects of electric field-dependent permittivity need to be considered.

In the experimental work, solution-cast poly(vinylidene difluoride) (PVDF) homopolymer PVDF films with high …

Low-Complexity Soft-Decision Feedback Turbo Equalization For Multilevel Modulations, Huang Lou

Doctoral Dissertations

"This dissertation proposes two new decision feedback equalization schemes suitable for multilevel modulation systems employing turbo equalization. One is soft-decision feedback equalization (SDFE) that takes into account the reliability of both soft a priori information and soft decisions of the data symbols. The proposed SDFE exhibits lower signal to noise ratio (SNR) threshold that is required for "water fall" bit error rate (BER) and much faster convergence than the near-optimal exact minimum mean square error linear equalizer (Exact-MMSE-LE) for high-order constellation modulations. The proposed SDFE also offers a low computational complexity compared to the Exact-MMSE-LE. The drawback of the SDFE …

The Pricing Of Multiple Exercisable American-Style Real Options, Yu Meng

Doctoral Dissertations

"Real options embedded in a project provide management with the flexibility to alter initial investment decisions, thus making them a practical tool for project planning and budgeting. Additional values are contributed to the underlying project due to the flexibilities that are provided by real options. This dissertation presents two models for pricing multiple exercisable American real options, one that employs the binomial tree method and the other one that employs the finite difference method. Different examples of multiple exercisable real options are discussed to demonstrate the two pricing models. Interactions between options and reality constraints are also considered. These two …

Data Fusion By Using Machine Learning And Computational Intelligence Techniques For Medical Image Analysis And Classification, Beibei Cheng

Doctoral Dissertations

"Data fusion is the process of integrating information from multiple sources to produce specific, comprehensive, unified data about an entity. Data fusion is categorized as low level, feature level and decision level. This research is focused on both investigating and developing feature- and decision-level data fusion for automated image analysis and classification. The common procedure for solving these problems can be described as: 1) process image for region of interest' detection, 2) extract features from the region of interest and 3) create learning model based on the feature data. Image processing techniques were performed using edge detection, a histogram threshold …

Stochastic Optimal Adaptive Controller And Communication Protocol Design For Networked Control Systems, Hao Xu

Doctoral Dissertations

"Networked Control System (NCS) is a recent topic of research wherein the feedback control loops are closed through a real-time communication network. Many design challenges surface in such systems due to network imperfections such as random delays, packet losses, quantization effects and so on. Since existing control techniques are unsuitable for such systems, in this dissertation, a suite of novel stochastic optimal adaptive design methodologies is undertaken for both linear and nonlinear NCS in presence of uncertain system dynamics and unknown network imperfections such as network-induced delays and packet losses. The design is introduced in five papers.

In Paper 1, …

Two Essays On The Domain Translation From Financial Options To Real Options, Hongyan Chen

Doctoral Dissertations

"Real options (ROs) extend the financial option pricing theory to the valuation of real asset investment and managerial flexibility under uncertainty. However, differences between financial and non-financial markets, and the complex real world environment of applications, build obstacles for the domain translation from financial options to ROs.

This dissertation is motivated by the challenges of domain translation and developed in two essays. The first essay studies the incentive function of ROs (named the RO incentive). The essay develops an option-game framework to model the RO incentive, examines the change of investment behavior caused by the RO incentive, and values the …

Fractal Oxidation Kinetics And Risk Evaluation Of Spontaneous Combustion In Coal Mines, Yutao Zhang

Doctoral Dissertations

"The spontaneous combustion of coal occurs when air supply is sufficient for the oxidation of coal and air velocity is insufficient for the dissipation of generated heat. Spontaneous combustion, if not eradicated immediately, may lead to coal ignition and even a full-blown fire. The fire may engulf a large area and spread further if they are not immediately attended to. This will not only endanger miners and mining operations, but also result in possible mine closures and even fatalities.

Porous structure has a significant effect on coal adsorption and spontaneous combustion. In this research, fractal theory was utilized to quantitatively …

Investigation Of Different Approaches To Combine Cable Information And Near-Field Scan Data For Radiated-Field Estimation, Keong W. Kam

Doctoral Dissertations

"Near-field scanning is often used to solve EMC problems. Aside from the purpose of visualization of near-fields, measured near-field data can be used to estimate far-field. One of many challenges associated with using near-field to far-field transform (NFFFT) technique for EMC application is the handling of attached cables. The objective of this investigation is to evaluate different methods to add cable information to the near-field data for far-field estimation. The investigation is carried out using numerical experiments in EMCoS EMC studio, which is a commercial MoM (Method of Moment) tool for EM simulation. Measurement results from a test structure are …

Measuring The Orientations Of Hidden Subvertical Joints In Highways Rock Cuts Using Ground Penetrating Radar In Combination With Lidar, Adnan Mohammed Aqeel

Doctoral Dissertations

"Mapping discontinuities in rock cuts and measuring their orientations is crucial in assessing the stability of rock masses. This can be done usually using manual methods such as scanline or advanced techniques such as LIDAR. However, these methods are used only to map exposed discontinuities which may cause underestimation for slope stability. Accordingly, ground penetrating radar (GPR) has been recently used to detect such hidden discontinuities.

The used 400 MHz monostatic GPR antenna was significantly able to detect and map hidden subvertical joints within 4 m depths in five sandstone highways rock cuts and within 3 m depths in two …

Global Homotopy Continuation And Stability Analysis: Optimal Application To Chemical Engineering Design, David Anthony Harney

Doctoral Dissertations

"The design of chemical engineering process equipment routinely necessitates the solution of large systems of non-linear equations. The processing speed of standard desktop computers have allowed for equation-oriented process simulators to become commercially viable. For a fully equation-oriented simulator to be competitive with standard iterative solvers, a robust and reliable non-linear equation solver is required and standard Newton methods fail to provide the necessary reliability.

Homotopy continuation methods have been proposed as a way to greatly expand the domain of convergence of the process simulator's equation solving algorithm. This research expands upon existing homotopy continuation algorithms, investigates bounding algorithms, corrector …

Search-Based System Architecture Development Using A Holistic Modeling Approach, Renzhong Wang

Doctoral Dissertations

"This dissertation presents an innovative approach to system architecting where search algorithms are used to explore design trade space for good architecture alternatives. Such an approach is achieved by integrating certain model construction, alternative generation, simulation, and assessment processes into a coherent and automated framework. This framework is facilitated by a holistic modeling approach that combines the capabilities of Object Process Methodology (OPM), Colored Petri Net (CPN), and feature model. The resultant holistic model can not only capture the structural, behavioral, and dynamic aspects of a system, allowing simulation and strong analysis methods to be applied, it can also specify …

Compressive Sensing For 3d Microwave Imaging Systems, Hamed Kajbaf

Doctoral Dissertations

"Compressed sensing (CS) image reconstruction techniques are developed and experimentally implemented for wideband microwave synthetic aperture radar (SAR) imaging systems with applications to nondestructive testing and evaluation. These techniques significantly reduce the number of spatial measurement points and, consequently, the acquisition time by sampling at a level lower than the Nyquist-Shannon rate. Benefiting from a reduced number of samples, this work successfully implemented two scanning procedures: the nonuniform raster and the optimum path.

Three CS reconstruction approaches are also proposed for the wideband microwave SAR-based imaging systems. The first approach reconstructs a full-set of raw data from undersampled measurements via …

Sustainable Engineering Practices In Transportation Projects, Kiran Rangarajan

Doctoral Dissertations

"Sustainability has become an important issue in transportation and infrastructure development projects. While several agencies are trying to incorporate a range of sustainability measures in their goals and missions, only a few planning agencies have been able to implement these policies and they are far from perfect. The low rate of success in implementing sustainable policies is primarily due to incomplete understanding of the system and the interaction between various elements of the system. The conventional planning efforts focuses mainly on performance measures pertaining to the system and its impact on the environment but seldom on the social and economic …

Real-Time Supply Chain Predictive Metrics, William Scott Hunter

Doctoral Dissertations

"Supply chains drive the production world. Virtually all products use a supply chain to produce them and they can determine the success of companies using them. The ability to manage supply chains is currently a mix of relationship management and science, combining personal and company relationships with data analysis.

The increased dependency on supply chains has increased the need to develop and use predictive real-time metrics to manage supply chain risk, measure suppliers and drive performance. Current metrics used are reactive and stagnant in nature. Real-time metrics will allow supply chain professionals to better manage risk. Current management techniques include …

Investigation Of Wellbore Stability In A North Sea Field Development, Steven Austin Hilgedick

Doctoral Dissertations

"Planning drilling operations is key to the development of oil and natural gas fields. As part of well design, wellbore stability and pore pressure analysis are main factors in determining the safe operating window for selecting mud density. The motivation for this research was to conduct wellbore stability based on exploration wells as basis for planning new offshore field developments with deviated and horizontal wells. A second objective was to investigate the use of a probabilistic approach to wellbore stability, and compare it to the conventional deterministic methods, in order to evaluate the value of including a probabilistic approach to …

Meso-Scale Fluidic Devices With Chemical Sensors For Biological Applications, Satya Gowthami Achanta

Doctoral Dissertations

"Molecular oxygen and humidity are some of the major environmental quantities being measured for various industrial and commercial applications. This dissertation focuses on the design, fabrication and characterization of optofluidic biosensor systems for oxygen and humidity quantification using color charge-coupled device (CCD) camera as a photodetector and LED panel as an excitation source. Meso-scale fluidic devices with integrated oxygen and humidity sensors for potential applications to hydrotropic and oxytropic studies of small plant roots have been investigated in this study. Meso-scale sensor platform was fabricated using porphyrine complex as the sensitive dye embedded within Ethyl Cellulose (EC) polymer matrix. Green …

Role Of Alloy Additions On Strengthening In 17-4 Ph Stainless Steel, Arpana S. Murthy

Doctoral Dissertations

"Alloy modifications by addition of niobium (Nb ), vanadium (V), nitrogen (N) and cobalt (Co) to cast 17-4 PH steel were investigated to determine the effect on mechanical properties. Additions of Nb, V, and N increased the yield strength from 1120 MPa to 1310 MPa while decreased the room temperature charpy V notch (CVN) toughness from 20 J to four Joules. The addition of Co to cast 17-4 PH steel enhanced the yield strength and CVN toughness from 1140 MPa to 1290 MPa and from 3.7 J to 5.5 J, respectively. In the base 17-4 PH steel, an increase in …

Strategic Management And Entrepreneurship As Economic Development Tools, Norbert Ziemer

Doctoral Dissertations

This research develops a framework of Biobased Entrepreneurial Ventures for Rural Economic Development. Rural economic development poses unique challenges and opportunities, based on available production assets, workforce trends like "brain drain," and access to industry clusters. However, certain entrepreneurial venture opportunities are preferable for rural economic development. Since supply chains are vital to business success, initial emphasis is placed on the biomass resource base to be transformed through entrepreneurial activity into higher economic value outputs. The literature contains research on specific opportunities in rural economic development (e.g. ethanol, wind power). Many of these are limited in scope and depend on …

Stability Challenges And Solutions In Current-Mode Controlled Power Electronic Converters, Seyed Mostafa Khazraei

Doctoral Dissertations

"This dissertation focuses on stability issues in single-staged and multi-staged current controlled power electronic converters. Most current-mode control (CMC) approaches suffer from sub-harmonic oscillations. An external ramp is usually added to solve this problem. However, to guarantee stability this ramp has to be designed for the worst possible case which consequently over damps the response. Adaptive slope compensation (ASC) methods are the solution for this problem. In paper 1 of this dissertation, first three ASC methods will be investigated and analyzed through their small signal models. Then, through simulation analyses and experimental test of a variable-input voltage converter the results …

Spatial-Temporal Reasoning Applications Of Computational Intelligence In The Game Of Go And Computer Networks, Tae-Hyung Kim

Doctoral Dissertations

"Spatial-temporal reasoning is the ability to reason with spatial images or information about space over time. In this dissertation, computational intelligence techniques are applied to computer Go and computer network applications. Among four experiments, the first three are related to the game of Go, and the last one concerns the routing problem in computer networks.

The first experiment represents the first training of a modified cellular simultaneous recurrent network (CSRN) trained with cellular particle swarm optimization (PSO). Another contribution is the development of a comprehensive theoretical study of a 2x2 Go research platform with a certified 5 dan Go expert. …