Engineering Commons^™

Nurturing Systems Thinking: Developing A Framework Based On The Human Factors Analysis And Classification System (Hfacs) To Improve Systems Development Processes, Arjun Vijayanarayanan

Doctoral Dissertations and Master's Theses

Large systems engineering projects have an astonishingly high failure rate. The reasons hypothesized for such a high failure rate include the neglect of nonsalient system elements such as social and human or organizational aspects of systems. Social and human factors have long been known to be critical elements of systems that are frequently ignored (e.g., Goguen, 1994). Systems engineering processes can benefit and be improved by effective utilization of a framework that helps developers expand their attention and efforts beyond the salient aspects of the system and the development process. In the aviation field, the Human Factors Analysis and Classification …

The Effect Of Shift Turnover Strategy And Time Pressure On Aviation Maintenance Technician Performance, William R. Warren

Doctoral Dissertations and Master's Theses

Aviation maintenance technicians (AMTs) provide the technical and applied knowledge required to maintain airworthiness in aircraft. In commercial aviation, maintenance tasks are performed across multiple shifts. When AMTs share a maintenance task between shifts, the shift turnover strategy used may determine if information is effectively transferred between AMTs. Ineffective shift turnover strategies are a contributing factor in many aviation accidents and incidents. Additionally, time constraints on certain maintenance tasks may cause AMTs to commit error when performing a task. The present study examined the effect of shift turnover strategy (face-to-face or written) and time pressure on error capture, accuracy, and …

Evaluation Of A Novel Non-Penetrating Electrode For Use In Dna Vaccination, Amy Donate, Domenico Coppola, Yolmari Cruz, Richard Heller

Bioelectrics Publications

Current progress in the development of vaccines has decreased the incidence of fatal and non-fatal infections and increased longevity. However, new technologies need to be developed to combat an emerging generation of infectious diseases. DNA vaccination has been demonstrated to have great potential for use with a wide variety of diseases. Alone, this technology does not generate a significant immune response for vaccination, but combined with delivery by electroporation (EP), can enhance plasmid expression and immunity. Most EP systems, while effective, can be invasive and painful making them less desirable for use in vaccination. Our lab recently developed a non-invasive …

Design And Analysis Of A Wind Energy Harvesting Circuit Using Piezoelectric Polymers, Jameson J. Thornton

Master's Theses

This thesis investigates a relatively new method for harvesting wind energy by using flexible piezoelectric polymers with additional sails to increase their ability to harvest wind energy. This paper also introduces a new topology deemed the “stacked buck” that allows for multiple inputs to a system with a single output. Derivations and analysis detail the workings of the “stacked buck” with a laboratory test to show a working model. This paper also reports another experiment done in a wind tunnel to analyze the capability of the piezoelectric polymers as sources to the “stacked buck” topology with measurements of the power …

Fabrication Of Poly(Vinylidene Fluoride) (Pvdf) Nanofibers Containing Nickel Nanoparticles As Future Energy Server Materials, Faheem A. Sheikh, Travis Cantu, Javier Macossay-Torres, Hern Kim

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In the present study, we introduce Poly(vinylidene fluoride) (PVDF) nanofibers containing nickel (Ni) nanoparticles (NPs) as a result of an electrospinning. Typically, a colloidal solution consisting of PVDF/Ni NPs was prepared to produce nanofibers embedded with solid NPs by electrospinning process. The resultant nanostructures were studied by SEM analyses, which confirmed well oriented nanofibers and good dispersion of Ni NPs over them. The XRD results demonstrated well crystalline feature of PVDF and Ni in the obtained nanostructures. Physiochemical aspects of prepared nano-structures were characterized for TEM which confirmed nanofibers were welloriented and had good dispersion of Ni NPs. Furthermore, the …

Computational Genomic Signatures And Metagenomics, Ozkan U. Nalbantoglu

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Mathematical characterizations of biological sequences form one of the main elements of bioinformatics. In this work, a class of DNA sequence characterization, namely computational genomics signatures, which capture global features of these sequences is used to address emerging computational biology challenges. Because of the species specificity and pervasiveness of genome signatures, it is possible to use these signatures to characterize and identify a genome or a taxonomic unit using a short genome fragment from that source. However, the identification accuracy is generally poor when the sequence model and the sequence distance measure are not selected carefully. We show that the …

Visualizing Time-Varying Harmonics Using Filter Banks, Carlos Augusto Duque, Paulo M. Silveira, Paulo F. Ribeiro

University Faculty Publications and Creative Works

Although it is well known that Fourier analysis is in reality only accurately applicable to steady state waveforms, it is a widely used tool to study and monitor time-varying signals, such as are commonplace in electrical power systems. The disadvantages of Fourier analysis, such as frequency spillover or problems due to sampling (data window) truncation can often be minimized by various windowing techniques, but they nevertheless exist. This paper demonstrates that it is possible to track and visualize amplitude and time-varying power systems harmonics, without frequency spillover caused by time-frequency techniques. This new tool allows for a clear visualization of …

Potential Environmental Benefits Of Extending Aircraft Pushback Operations, Dennis R. O'Connell

Mechanical & Aerospace Engineering Theses & Dissertations

This study considered extending the operational use of pushback tractors to perform taxi-out airport ground operations for commercial aircraft as an alternative to using aircraft power plants for this operation. Pushback tractors are designed to reverse aircraft from the terminal gate to a position where the aircraft can taxi independently to the departure runway. In this investigation the process of pushback would be extended to pulling the aircraft to the departure runway then returning the pushback tractor to the terminal of origin, a new procedure known as extended pushback.

Data from major aircraft operators and engine manufacturers were collected to …

The Path Of Innovation: From Traditional Classroom To Hybrid Experience, Lulu Sun, Matthew Kindy, Caroline Liron

Publications

“Introduction to Computing for Engineers” is a programming course emphasizing problem solving. However, the lack of time for practice and the algorithm-centric nature of programming results in inadequate comprehension of this course material. Through course evaluations, faculty experience, and discussions, we feel that students in a programming course should have more time for “hands-on” learning, rather than trying to absorb content through lectures. We believe that by getting students involved and excited about engineering from the beginning of their first year, we will markedly improve comprehension of the course content. To that end, a hybrid course is implemented that involves …

Addressing Water Quality Issues In Rural Cameroon With Household Biosand Filters, Laine Klopfensten, Laura Petrasky, Valerie Winton, Jeff Brown

Publications

This paper describes an ongoing collaboration between the Hope College student chapter of Engineers Without Borders – USA and the rural community of Nkuv in the Northwest Province of Cameroon related to improving drinking water quality using Manz biosand filters. The collaboration began in 2006 and focused on developing a community-based construction and distribution model for household water treatment units. Results from microbiology testing of the constructed filters indicate that this water treatment method is effective for improving water quality in rural areas. The results also highlight the need for ongoing assessment and adapting community education programs to provide necessary …

Experimental Investigation Of Natural Fiber Reinforced Composite, Irene Samy Fahim

Theses and Dissertations

There is a growing use of polymers in different applications worldwide. This phenomenon resulted in an enormous increase in the amount of plastic waste. These wastes have significant impacts on the environment including pollution and depletion of resources. Recycling plastic waste and reusing it helps in alleviating environmental degradation. The amount of recycled plastics all over the world not utilized is huge. U.S.A recycled 5.7% of the total plastics generated and Western Europe recycled 39% of total amount of plastics consumed [1]. This research studies the potential usage of virgin and recycled polymer reinforced with natural fiber such as rice …

A Least Squares Closure Approximation For Liquid Crystalline Polymers, Traci Ann Sievenpiper

Mathematics & Statistics Theses & Dissertations

An introduction to existing closure schemes for the Doi-Hess kinetic theory of liquid crystalline polymers is provided. A new closure scheme is devised based on a least squares fit of a linear combination of the Doi, Tsuji-Rey, Hinch-Leal I, and Hinch-Leal II closure schemes. The orientation tensor and rate-of-strain tensor are fit separately using data generated from the kinetic solution of the Smoluchowski equation. The known behavior of the kinetic solution and existing closure schemes at equilibrium is compared with that of the new closure scheme. The performance of the proposed closure scheme in simple shear flow for a variety …

Data Aggregation And Dissemination In Vehicular Ad-Hoc Networks, Khaled Ibrahim

Computer Science Theses & Dissertations

Vehicular Ad-Hoc Networks (VANETs) are a fast growing technology that many governments and automobile manufacturers are investing in to provide not only safer and more secure roads, but also informational and entertainment-based applications for drivers. The applications developed for VANETs can be classified into multiple categories (safety, informational, entertainment). Most VANET applications, regardless of their category, depend on having certain vehicular data(vehicular speed, X position and Y position) available. Although these applications appear to use the same vehicular data, the characteristics of this data (i.e., amount, accuracy, and update rate) will vary based on the application category. For …

Characterizations Of Atmospheric Pressure Low Temperature Plasma Jets And Their Applications, Erdinc Karakas

Electrical & Computer Engineering Theses & Dissertations

Atmospheric pressure low temperature plasma jets (APLTPJs) driven by short pulses have recently received great attention because of their potential in biomedical and environmental applications. This potential is due to their user-friendly features, such as low temperature, low risk of arcing, operation at atmospheric pressure, easy handheld operation, and low concentration of ozone generation. Recent experimental observations indicate that an ionization wave exists and propagates along the plasma jet. The plasma jet created by this ionization wave is not a continuous medium but rather consists of a bullet-like-structure known as "Plasma Bullet". More interestingly, these plasma bullets actually have a …

Learning Local Features Using Boosted Trees For Face Recognition, Rajkiran Gottumukkal

Electrical & Computer Engineering Theses & Dissertations

Face recognition is fundamental to a number of significant applications that include but not limited to video surveillance and content based image retrieval. Some of the challenges which make this task difficult are variations in faces due to changes in pose, illumination and deformation. This dissertation proposes a face recognition system to overcome these difficulties. We propose methods for different stages of face recognition which will make the system more robust to these variations. We propose a novel method to perform skin segmentation which is fast and able to perform well under different illumination conditions. We also propose a method …

A Structured Project-Risk Management And Life Cycle Framework For Complex Systems: Ship Repair And Maintenance (Sr&M) Projects, Michael Craig Plumb

Engineering Management & Systems Engineering Theses & Dissertations

This dissertation contributes to insights regarding the implications of using Project Risk Management (PRM) and Life Cycle Assessment (LCA) in managing projects for a complex system. The PRM approach apprehends many forms of risk both internal and external within a given project and assists the manager in determining the level of importance of each individual project phase and component to optimize project success. The life cycle approach to project management is used with short-term limitations with respect to a product's life cycle over several years. The literature discusses many tools and techniques that assist project managers in implementing optimal solutions, …

A Pilot Model For Investigating Biodynamic Coupling Due To Aeroservoelastic Accelerations, Brandon Cowen

Mechanical & Aerospace Engineering Theses & Dissertations

Supersonic Transport Aircraft tend to have slender fuselages with respect to their subsonic counterparts. This design feature leads to increased aeroservoelastic bending at low resonant frequencies closer to the frequencies of pilot commands and the corresponding rigid body accelerations. Aeroelastic accelerations of certain frequencies and phase lags at the pilot station have been seen to involuntarily pass through the pilot's body to the control inceptor. When the pilot commands rigid body accelerations in phase with the structural response, the structural accelerations grow. Thus biodynamic coupling represents the coupling between the feedthrough of pilot station acceleration through the pilot's body, with …

Direct Current Electrokinetic Particle Transport In Micro/Nano-Fluidics, Ye Ai

Mechanical & Aerospace Engineering Theses & Dissertations

Electrokinetics has been widely used to propel and manipulate particles in micro/nano-fluidics. The first part of this dissertation focuses on numerical and experimental studies of direct current (DC) electrokinetic particle transport in microfluidics, with emphasis on dielectrophoretic (DEP) effect. Especially, the electrokinetic transports of spherical particles in a converging-diverging microchannel and an L-shaped microchannel, and cylindrical algal cells in a straight microchannel have been numerically and experimentally studied. The numerical predictions are in quantitative agreement with our own and other researchers' experimental results. It has been demonstrated that the DC DEP effect, neglected in existing numerical models, plays an important …

Exploring The Effects Of Cooperative Adaptive Cruise Control In Mitigating Traffic Congestion, Georges M. Arnaout

Engineering Management & Systems Engineering Theses & Dissertations

The aim of this research is to examine the impact of CACC (Cooperative Adaptive Cruise Control) equipped vehicles on traffic-flow characteristics of a multilane highway system. The research identifies how CACC vehicles affect the dynamics of traffic flow on a road network and demonstrates the potential benefits of reducing traffic congestion due to stop-and-go traffic conditions. An agent-based traffic simulation model is developed specifically to examine the effect of these intelligent vehicles on the traffic flow dynamics. Traffic performance metrics characterizing the evolution of traffic congestion throughout the road network, are analyzed. Different CACC penetration levels are studied.

The positive …

Evaluation System Design And Academic Performance Analysis Using Clustering And Simulation, Volkan Cakir

Engineering Management & Systems Engineering Theses & Dissertations

The starting point of this study was to understand the possible causes of evaluation system change in a military academic environment. With that motivation the objectives of this study were defined as examining student profiles in a military academy, establishing the nature of academic performance, comparing student groups that were identified by course scores, analyzing student performance changes over time and developing a manageable evaluation system and curriculum by comparing different scenarios.

An analysis was performed on the literature on academic performance prediction, cluster analysis methodologies and their development, and specifically summarized cluster analytic academic performance studies where these two …

Optimization Models And Approximate Algorithms For The Aerial Refueling Scheduling And Rescheduling Problems, Sezgin Kaplan

Engineering Management & Systems Engineering Theses & Dissertations

The Aerial Refueling Scheduling Problem (ARSP) can be defined as determining the refueling completion times for fighter aircrafts (jobs) on multiple tankers (machines) to minimize the total weighted tardiness. ARSP can be modeled as a parallel machine scheduling with release times and due date-to-deadline window. ARSP assumes that the jobs have different release times, due dates, and due date-to-deadline windows between the refueling due date and a deadline to return without refueling. The Aerial Refueling Rescheduling Problem (ARRP), on the other hand, can be defined as updating the existing AR schedule after being disrupted by job related events including the …

Random Keys Genetic Algorithms Scheduling And Rescheduling Systems For Common Production Systems, Elkin Rodriguez-Velasquez

Engineering Management & Systems Engineering Theses & Dissertations

The majority of scheduling research deals with problems in specific production environments with specific objective functions. However, in many cases, more than one problem type and/or objective function exists, resulting in the need for a more generic and flexible system to generate schedules. Furthermore, most of the published scheduling research focuses on creating an optimal or near optimal initial schedule during the planning phase. However, after production processes start, circumstances like machine breakdowns, urgent jobs, and other unplanned events may render the schedule suboptimal, obsolete or even infeasible resulting in a "rescheduling" problem, which is typically also addressed for a …

Growth Of Alkali Antimonide Photosensitive Thin Films, George Annobil

Electrical & Computer Engineering Theses & Dissertations

The experiment performed in this research addresses the growth of an alkali antimonide photosensitive film. Research was conducted to understand and develop a growth technique for a unique vapor deposition system in a vacuum environment. Specifically, the grown film will be utilized as a photocathode, and hence quantum efficiency (QE) and photocathode lifetime measurements are conducted. The research presents the successful growth of the binary compound cesium antimonide with achieved quantum efficiency of ~0.07% at ~240V anode bias. This experimental result demonstrated that the deposition technique was reliable in producing a feasible cathode. It further allowed the verification of theoretical …

A Study Of Diversity Techniques For Lte Wireless Systems, Ferhat Kaplan

Electrical & Computer Engineering Theses & Dissertations

The demand of attaining information and the wish to communicating anytime and anywhere has caused numerous innovations in the digital communication world. Today, approximately half of the people on earth somehow use wireless technology which is in every part of our lives. LTE (Long Term Evolution) and WIMAX (Worldwide Interoperability for Microwave Access) standards are the two leading wireless technologies, which support high data rates, multimedia applications, and voice video communications at very high speeds, also called 4G cellular systems in the global market.

These high expectations from wireless technology have revealed multiple antenna techniques which improve the performance and …

Ionic Current Rectification Phenomena In Asymmetrical Polymer Nanopores Under Salt Gradients, Murat Bakirci

Mechanical & Aerospace Engineering Theses & Dissertations

The magnitude of current through a conical nanopore filled with an electrolyte solution depends on the polarity of the applied bias, indicating an asymmetric diode-like current-voltage (I-V) curve. This kind of phenomenon refers to ionic current rectification (ICR), which is of interest because many ion-channel proteins in cellular membranes are rectifying. In addition, ICR in nanopores can be used to control ion concentrations in nano- and microfluidic systems. In this study, the ICR phenomenon through a conical nanopore simultaneously subjected to an electric field and salt concentration gradient is experimentally and numerically investigated.

The experiments were conducted in an Izon's …

A Framework For Incident Detection And Notification In Vehicular Ad-Hoc Networks, Mahmoud Abuelela

Computer Science Theses & Dissertations

The US Department of Transportation (US-DOT) estimates that over half of all congestion events are caused by highway incidents rather than by rush-hour traffic in big cities. The US-DOT also notes that in a single year, congested highways due to traffic incidents cost over $75 billion in lost worker productivity and over 8.4 billion gallons of fuel. Further, the National Highway Traffic Safety Administration (NHTSA) indicates that congested roads are one of the leading causes of traffic accidents, and in 2005 an average of 119 persons died each day in motor vehicle accidents.

Recently, Vehicular Ad-hoc Networks (VANET) employing a …

Compensation Techniques In Accelerator Physics, Hisham Kamal Sayed

Physics Theses & Dissertations

Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two …

Solving The Vehicle Re-Identification Problem By Using Neural Networks, Tanweer Rashid

Computational Modeling & Simulation Engineering Theses & Dissertations

Vehicle re-identification is the process by which vehicle attributes measured at one point on a road network are compared to vehicle attributes measured at another point in an effort to match vehicles without using any unique identifiers such as license plate numbers. A match is made if the two measurements are estimated to belong to the same vehicle. Vehicle attributes can be sensor readings such as loop induction signatures, or they can also be actual vehicle characteristics such as length, weight, number of axles, etc. This research makes use of vehicle length, travel time, axle spacing and axle weights for …

Investigation And Comparison Of Proportional Navigation Guidance And Beam Rider Guidance, Ertac Olgun

Electrical & Computer Engineering Theses & Dissertations

Air defense has an increasing importance in today's wars. To gain the advantage in air combat, pursuit interceptor aircraft, which use Air-to-Air Missiles (AAMs), have become more and more significant. However, these are not sufficient alone. The importance of Surface-to-Air Missiles (SAMs) also can not be ignored in air defense.

SAMs can use different tactical navigation guidance methods. Of these, two of the more important guidance methods are Proportional Navigation Guidance and Beam Rider Guidance, which are investigated in this thesis. To understand the idea better, a brief description and discussion of missiles are provided. Parts of the guided missiles …

Long Term Surface Power Generator Design For Mars: Autonomously Deployable Photovoltaic Solar Arrays Along With Regenerative Fuel Cell Modules, Omer Demirok

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis studies the feasibility of incorporating a large autonomously deployed photovoltaic solar array power system as the primary power source for a large fixed Mars base. A mission duration of 10 Earth years has been assumed and the nominal power demands have been specified as a minimum of 40 kW, during daytime operation and a continuous 10 kW. demand for nighttime operation.

The overall system design developed in this thesis has an estimated total mass of 7,400 kg, when utilizing hydrogenated amorphous silicon thin film solar arrays and an estimated total mass of 5,100 kg when utilizing polycrystalline copper-indium-diselenide …