Engineering Commons^™

Evaluating The Impact Of Adopting 3d Printing Services On The Retailers, Sharareh Rajaei Dehkordi

Dissertations

As additive manufacturing technology becomes more responsive to consumers’ demand, one important question for the retailers is whether they should provide 3D printing services in their brick-and-mortar store in addition to the traditional off-the-shelf product? If so, what should be the retailers pricing scheme to achieve a higher profit? What should be the optimal inventory level of off-the-shelf products? What is the optimal capacity of 3D printers? In this study, stochastic models are examined to capture the joint optimal 3D product price and capacity of 3D printers to maximize retailer’s expected profit while considering consumer product choices. Moreover, a stochastic …

Interference Unmixing And Estimation Technique For Improvement Of Speech Separation Performance, Ankur Maurya

Dissertations

Presence of noise in the speech can sometimes become annoying as it can lead to loss of important data or create misunderstandings between the communications area which can lead to major problems associated to loss of time and money. This thesis focuses to filter out noise form a speech signal which is simulated in Matlab/Octave software while making a comparison between temporal resolution of signal with respect to the spectral resolution of the signal in which the parameters such as the size of window length are varied in order to obtain the best speech separation performance. To get the best …

Preparation Of Benzoxazine Monomers And Prepolymers From Continuous Reactor: Effects Of Molecular Architecture On Properties, Andrew S. Frazee

Dissertations

Despite the modularity in molecular design and high-performance properties of benzoxazine thermoset chemistries, there are two primary shortcomings of benzoxazine marketability. Firstly, multifunctional benzoxazines are unfavorable for processing as they are glassy solids at ambient temperature. Secondly, benzoxazine chemistries are commercially synthesized using batch reactors, which are energy intensive and require the use of environmentally unfavorable solvents.

The purpose of the work herein is to address these shortcomings, which include:

1.) interrelationships between molecular architectures of synthesized monofunctional benzoxazine monomers and their ambient temperature physical states (i.e. liquid or solid) using molecular dynamics simulations and experimental comparisons,

2.) continuous high-shear …

Distributed Model Predictive Control Of Power Converters In Microsrids Under Different Modes Of Operation, Riyadh Toman Thahab Toman

Dissertations

Microgrids consist of many distributed energy sources (DERs) and the overall system is viewed as a number of subsystems. In this work, a finite control set model predictive control is proposed to control power converters in both grid and island modes of operation of the microgrid. Each subsystem is assigned a local controller that relies on measurements of common coupling point (PCC) and/or terminal quantities to provide accurate regulation of current or voltage components. This meets the local objective of each subsystem and contributes to the global objective of the microgrid.

In the first part of the work, a microgrid …

Self-Generated Absorption Filter Based Optical Densitometry Calculations For Expanded Gamut And Spot Color Printing On Paperboard For Packaging Applications And Proposed Oba Index, Awadhoot Vijaykant Shendye

Dissertations

In the printing industry, process color printing is a very common way of reproduction of color photographic images. As continuous tone reproduction is not possible, images are converted to halftone format. Process control of a halftone image quality is carried out by measuring optical density of solid patches. ISO 5 defines measurement of optical density, formula, filters and requirements. As per ISO document optical density can be calculated only for the 4 colors cyan, magenta, yellow and black, known as process colors. To enhance quality of color reproduction of images, the number of reproducible colors are increased by gamut expansion. …

Bio-Socially Inspired Strategies In Support Of Dynamic Spectrum Access: An Evolutionary Game Theory Perspective, Mohammad Ali Marzoug Abu Shattal

Dissertations

Dynamic Spectrum Access (DSA) has been introduced to fulfill the expanded need for spectrum by different wireless networks and applications. Within the realm of spectrum access, the problem of "spectrum crunch" is present since some of the spectrum bands are overcrowded and others are underutilized. DSA aims to alleviate the problem of spectrum crunch. In DSA, Primary Users (PUs) allow Secondary Users (SUs) to access the spectrum as long as they do not interfere with PU transmissions beyond a pre-agreed acceptable level. In this work, a bio-socially inspired approach is proposed for SU interactions in support of better throughput for …

Optimal Combiners For Multiple Classifier Systems, Mohammed Falih Hassan

Dissertations

A Multiple Classifier System (MCS) is designed to combine classification results of an ensemble of different classifiers and consequently to produce the highest possible classification output. MCS has recently drawn growing attention and has become a necessity, especially when a problem involves a large class of noisy data or when using a single pattern classifier that has serious drawbacks in its results. A wide range of pattern recognition applications have benefited from the implementation of MCS, these include areas such as handwriting recognition, incremental learning, data fusion, feature selection, and a large variety of medical applications.

To achieve optimal ensemble …

Development Of Flexible Sensing Systems And Energy Harvesters Using Printing Techniques, Sepehr Emamian

Dissertations

Printed electronics (PE) has been gaining a significant level of interest and is being used for developing a wide range of electronic systems for various applications, specifically in the sensor fields. This dissertation focuses on the development of flexible sensors and energy harvesters for application in sensing systems by employing additive manufacturing processes.

Initially, an efficient surface enhanced Raman spectroscopy (SERS) substrate was fabricated by gravure printing a thin film of silver nanoparticle ink on a flexible polyethylene terephthalate (PET) sheet. The feasibility of the printed substrate to be used as a SERS substrate for the detection of explosive materials, …

A Novel E-Voting System With Diverse Security Features, Haijun Pan

Dissertations

Internet-based E-voting systems can offer great benefits over traditional voting machines in areas, such as protecting voter and candidate privacy, providing accurate vote counting, preventing voter fraud, and shortening the time of vote counting. This dissertation introduces, establishes and improves Internet-based E-voting systems on various aspects of the voting procedure. In addition, our designs also enable voters to track their votes which is a very important element in any elections.

Our novel Internet-based E-voting system is based on the following realistic assumptions: (1) The election authorities are not 100% trustworthy; (2) The E-voting system itself is not 100% trustworthy; (3) …

Appointment Planning And Scheduling In Primary Care, Babak Hoseini

Dissertations

The Affordable Care Act (ACA) puts greater emphasis on disease prevention and better quality of care; as a result, primary care is becoming a vital component in the health care system. However, long waits for the next available appointments and delays in doctors offices combined with no-shows and late cancellations have resulted in low efficiency and high costs.

This dissertation develops an innovative stochastic model for patient planning and scheduling in order to reduce patients’ waiting time and optimize primary care providers’ utility. In order to facilitate access to patients who request a same-day appointment, a new appointment system is …

Machine Learning Based Digital Image Forensics And Steganalysis, Guanshuo Xu

Dissertations

The security and trustworthiness of digital images have become crucial issues due to the simplicity of malicious processing. Therefore, the research on image steganalysis (determining if a given image has secret information hidden inside) and image forensics (determining the origin and authenticity of a given image and revealing the processing history the image has gone through) has become crucial to the digital society.

In this dissertation, the steganalysis and forensics of digital images are treated as pattern classification problems so as to make advanced machine learning (ML) methods applicable. Three topics are covered: (1) architectural design of convolutional neural networks …

Aerosol Transport By Coughing In A Depressurized And Air-Conditioned Chamber, Bo Zhang

Dissertations

Expiratory droplets from human coughing in an air-conditioned environment have always been considered to be potential carriers of pathogens, responsible for respiratory disease transmission. The air movement/circulation and ambient conditions such as pressure and temperature are all key factors of aerosol transport. To study the transmission of disease by human coughing in a depressurized air-conditioned chamber, there are many technical challenges, including the following: 1) the study of simulating human coughing; 2) the collection of aerosol generated by coughing; 3) the CFD simulation of coughing-induced aerosol transport in an air-conditioned chamber; 4) the validation of such a CFD simulation by …

An Artificial Neural Network Model For Predicting Freeway Work Zone Delays With Big Data, Bo Du

Dissertations

Lane closures due to road reconstruction and maintenance have resulted in a major source of non-recurring congestion on freeways. It is extremely important to accurately quantify the associated mobility impact so that a cost-effective work zone schedule and an efficient traffic management plan can be developed. Therefore, the development of a sound model for predicting delays or road users is desirable.

A comprehensive literature review on existing work zone delay prediction models (i.e., deterministic queuing model and shock wave model) is conducted in this study, which explores the advantages, disadvantages, and limitations of different modeling approaches. The performance of those …

Silicon-Germanium Nanowire Heterojunctions: Optical And Electrical Properties, Xiaolu Wang

Dissertations

Semiconductor nanowires are quasi-one-dimensional objects with unique physical properties and strong potential in nanophotonics, nanoelectronics, biosensing, and solar cell devices. The next challenge in the development of nanowire functional structures is the nanowire axial heterojunctions, especially lattice mismatched heterojunctions. Si and Ge have a considerable lattice mismatch of ~ 4.2% as well as a mismatch in the coefficient of thermal expansion, and the formation of a Si_1-xGe_x transition layer at the heterointerface creates a non-uniform strain and modifies the band structures of the adjacent Si and Ge nanowire segments. These nanostructures are produced by catalytic chemical …

Formulation And Dissolution Of Polymer Strip Films For The Delivery Of Poorly Water-Soluble Drug Nanoparticles, Scott Matthew Krull

Dissertations

Polymer films have emerged as a promising platform for delivery of pharmaceutical products in recent years due to simplified processing, greater flexibility, and improved patient compliance over traditional solid dosage forms. However, the large majority of efforts have focused on incorporation of water-soluble drugs. The objective of this dissertation is to explore the robustness and versatility of the strip film platform for delivery of poorly water-soluble drug nanoparticles to ultimately develop a predictive model for drug release from such films.

The robustness of the polymer strip film platform to successfully deliver a variety of poorly water-soluble drug nanoparticles without the …

Field Induced Assembly Of Particulate Systems, Kinnari Shah

Dissertations

The primary focus of the first part of this dissertation is to study the AC field-driven assembly of monodisperse silica and glass particles on liquid - liquid interface and forming a liquid film of uniform thickness having arrangement of particles on it. This liquid film with arrangement of regular particles can be converted into a solid film by curing top UV curable liquid. Here, electric field is used as a tool to facilitate AC field-driven assembly. The work describes the assembly of different size of regular particles and effective development of solid film.

It is also shown that particles of …

Optimization Of The Front End Of Cdte Solar Cells, Yunfei Chen

Dissertations

The front end of CdTe solar cells consists of two layers: a transparent conducting oxide (TCO) layer and a window layer. New wider band gap materials, ZnMgO are being used to replace CdS as the window layer for the purpose of removing blue loss. For ZnMgO, three important parameters, including the atomic Mg content (x), thickness (t), and doping concentration (n) can play important roles on the performance of CdTe solar cells. In this dissertation, systematic simulation, by solar cell capacitance simulator (SCAPS), and experiments are used to investigate the influences of these …

Co2 Reduction Over Noble Metal/Carbon Nanotube Catalyst, Yuan Zhu

Dissertations

Carbon nanotube-based Pt/Pd and Ru catalysts, independently synthesized by a microwave reaction technique, show good catalytic activity for CO2 reduction in the contexts of dry reforming (DR) of methane (CH₄ + CO₂ -> 2CO + 2H₂) and reverse water gas shift (RWGS) (H2 + CO₂ -> CO + H₂O). Reaction temperatures range from 773 to 973 K, with system pressure at 30 psig. The feed molar ratios CH4/CO₂ and CO₂/H₂ are varied from 0.5 to 2.0. Reactant conversions in DR and RWGS are strongly influenced by temperature and feed …

Assessment Of Nanocomposites Vs. Amorphous Solid Dispersions For Dissolution Enhancement Of Bcs Class Ii Drugs, Meng Li

Dissertations

Nanoparticle-based formulations (nanocomposites) and amorphous solid dispersions, shortly ASDs, are two major pharmaceutical formulation platforms used for the bioavailability enhancement of poorly water-soluble drugs. While they both have several advantages-disadvantages, a scientific comparative assessment of their drug release performance and dissolution mechanisms at different drug doses is not available. With the goal of addressing this issue, the dissertation aims to achieve three major objectives: (1) develop a processing-formulation understanding of wet media milling process for fast-efficient production of drug nanoparticles in stable nanosuspension form, (2) elucidate the impact of various classes dispersants on drug release rate and mechanisms during the …

Modeling Subconcussive And Cumulative Subconcussive Impacts Using A Lateral Fluid Percusion Injury Device, Todd Long

Dissertations

Repetitive mTBI and concussion are a major risk factor for developing long-term cognitive and behavioral impairments. Curiously, cumulative head injuries sustained over an individuals’ career, involving contact activities (e.g. athletes and military personnel), are beginning to be implicated in long-term consequences, such as dementia. Recently, chronic traumatic encephalopathy (CTE) has gained momentum in the science and medical community as a neurodegenerative disease of repetitive head injuries. CTE was observed at autopsy of former athletes that did not closely correlate with a clinical history of concussion. Thus, suggesting cumulative subconcussive insults may induce long-term damage.

Investigating the etiology of subconcussive and …

Characterization Of Microporous Ectfe Membranes Exposed To Different Liquid Media And ?-Radiation And Nanoparticle Microfiltration Through Such Membranes, Na Yao

Dissertations

Microporous polymeric membranes are used in a variety of applications for separations, purification as well as barrier function. A major application is for microfiltration (MF). Changes in the properties of MF membranes exposed to acids, bases and organic solvents are of interest in semiconductor processing as well as in membrane contactor applications. Microfiltration membranes used for sterilization in beverage, biotechnology and pharmaceutical industries are sterilized by gamma radiation among others. Irradiation-induced degradation in membrane properties should be known. A variety of fluoropolymer-based microporous membranes are available with varying properties. Ethylene chlorotrifluoroethylene (ECTFE) membranes are a new addition and are of …

Erosion Behavior And Scour Risk Of Extremely Coarse Streambeds, Abolfazl Bayat

Dissertations

Bridge scour, which is the erosion of soil and rock around bridge abutments and piers, is the principal cause of bridge failure in the United States and around the world. Previous investigations of scour have focused mostly on fine sediments such as sand, silt, and small gravel, because such alluvium underlies a majority of bridges. The erosion resistance of coarser sediments has received limited attention to date, even though they dominate many small to medium-size rivers in the northern tiers of the United States, Europe, and Asia. This study focuses on the scour behavior of extremely coarse particles (ECP), namely …

Simulation, Performance And Interference Analysis Of Multi-User Visible Light Communication Systems, Adel Aldalbahi

Dissertations

The emergence of new physical media such as optical wireless, and the ability to aggregate these new media with legacy networks motivate the study of heterogeneous network performance, especially with respect to the design of protocols to best exploit the characteristics of each medium.

This study considers Visible Light Communications (VLC), which is expected to coexist with legacy and future radio frequency (RF) media. While most of the research on VLC has been done on optimizing the physical medium, research on higher network layers is only beginning to gain attention, requiring new analyses and tools for performance analysis.

The first …

Can A Strictly Defined Security Configuration For Iot Devices Mitigate The Risk Of Exploitation By Botnet Malware?, David Kennefick

Dissertations

The internet that we know and use every day is the internet of people, a collection of knowledge and data that can be accessed anywhere is the world anytime from many devices. The internet of the future is the Internet of Things. The Internet of Things is a collection of automated technology that is designed to be run autonomously, but on devices designed for humans to use. In 2016 the Mirai malware has shown there are underlying vulnerabilities in devices connected to the internet of things. Mirai is specifically designed to recognise and exploit IoT devices and it has been …

An Analysis Of Predicting Job Titles Using Job Descriptions, John Lynch

Dissertations

A job title is an all-encompassing very short form description that conveys all of the pertinent information relating to a job. The job title typically encapsulates - and should encapsulate - the domain, role and level of responsibility of any given job. Significant value is attached to job titles both internally within organisational structures and to individual job holders. Organisations map out all employees in an organogram on the basis of job titles. This has a bearing on issues like salary, level and scale of responsibility, employee selection and so on. Employees draw value from their own job titles as …

Cybercrime: An Investigation Of The Attitudes And Environmental Factors That Make People More Willing To Participate In Online Crime, Dearbhail Kirwan

Dissertations

Cybercrime incidence rates are increasing. In order to identify solutions to this problem, the sources of cybercrime need to be identified. This research attempted to identify a potential set of circumstances that create an environment in which people are more likely to engage in cybercrime. There are three aspects to this; (1) Behaviour on the internet – Are people more likely to engage in illicit activities online than in the physical world? (2) Crime Perceptions – Do people perceive cybercrime as being less serious than non-cybercrime? (3) Resources on the Internet – Are people aware of the types of free …

“How Short Is A Piece Of String?”: An Investigation Into The Impact Of Text Length On Short-Text Classification Accuracy, Austin Mccartney

Dissertations

The recent increase in the widespread use of short messages, for example micro-blogs or SMS communications, has created an opportunity to harvest a vast amount of information through machine-based classification. However, traditional classification methods have failed to produce accuracies comparable to those obtained from similar classification of longer texts. Several approaches have been employed to extend traditional methods to overcome this problem, including the enhancement of the original texts through the construction of associations with external data enrichment sources, ranging from thesauri and semantic nets such as Wordnet, to pre-built online taxonomies such as Wikipedia. Other avenues of investigation have …

The Use Of Persistent Explorer Artificial Ants To Solve The Car Sequencing Problem, Kieran O'Sullivan

Dissertations

Ant Colony Optimisation is a widely researched meta-heuristic which uses the behaviour and pheromone laying activities of foraging ants to find paths through graphs. Since the early 1990’s this approach has been applied to problems such as the Travelling Salesman Problem, Quadratic Assignment Problem and Car Sequencing Problem to name a few. The ACO is not without its problems it tends to find good local optima and not good global optima. To solve this problem modifications have been made to the original ACO such as the Max Min ant system. Other solutions involve combining it with Evolutionary Algorithms to improve …

Can Deep Learning Techniques Improve The Risk Adjusted Returns From Enhanced Indexing Investment Strategies, Anthony Grace

Dissertations

Deep learning techniques have been widely applied in the field of stock market prediction particularly with respect to the implementation of active trading strategies. However, the area of portfolio management and passive portfolio management in particular has been much less well served by research to date. This research project conducts an investigation into the science underlying the implementation of portfolio management strategies in practice focusing on enhanced indexing strategies. Enhanced indexing is a passive management approach which introduces an element of active management with the aim of achieving a level of active return through small adjustments to the portfolio weights. …

Estimating Vehicles Emissions At Signalized Intersections In The Highway Capacity Manual, Yuanyuan Fan

Dissertations

Over the past decades, motor vehicle volumes have continued to increase at a high rate. As a result, engineers in the transportation field not only need more robust knowledge of traffic operation control and transportation planning, but more attention is also needed to understand and estimate the influences that this increasing volume of vehicles has on the environment, especially the influence on air quality. The EPA has stated that reducing carbon monoxide (CO) from vehicle emissions is the most significant way to control air pollution from the transportation sector.

The Highway Capacity Manual is a national and international resource that …