Engineering Commons^™

Operational Decision Making For Medical Clinics Through The Use Of Simulation And Multi-Attribute Utility Theory., Bo Sun

Electronic Theses and Dissertations

Currently, health care is a large industry that concerns everyone. Outpatient health care is an important part of the American health care system and is one of the strongest growth areas in the health care system. Many people pay attention to how to keep basic health care available to as many people as possible. A large health care system is usually evaluated by many performance measures. For example, the managers of a medical clinic are concerned about increasing staff utilization; both managers and patients are concerned about patient waiting time. In this dissertation, we study decision making for clinics in …

Mixing And Mean Age In Multiphase Systems., David Chandler Russ

Electronic Theses and Dissertations

Mean age theory is a useful tool for analyzing mixing by providing spatial distributions of time based data for material inside a system using a steady-state CFD approach, but has been limited to single phase systems. Mean age theory was extended here to multiphase systems by defining the scalar tracer concentration independently for individual phases, which allows mean age to be solved at steady-state for each phase independently within a multiphase system. The theory was validated by comparing multiphase mean age (MMA) distributions extracted from spatial distributions determined computationally at two locations where RTDs were experimentally measured in a water-oil …

Molecule Assisted Hydrothermal Synthesis Of Zinc Oxide Nanomaterials With Possible Applicatios In Solar Energy, Austin Major Shearin

Graduate Theses/Dissertations

A molecule assisted hydrothermal synthesis of zinc oxide nanomaterials with L-lysine has been performed to understand the interaction between the biomolecule and the zinc oxide structures during synthesis. The molecule alters the growth kinetics during the formation of the nanomaterials in the hydrothermal reaction. This alters the size and shape of the materials as seen in the scanning electron microscope. X-ray diffraction results confirm the hexagonal Wurtzite structure that zinc oxide forms and indicates no other phases in the nanomaterial. The lattice parameters are not altered, but the atomic percentage of zinc to oxygen within the structure changes as analyzed …

Nonparametric Anomaly Detection And Secure Communication, Shaofeng Zou

Dissertations - ALL

Two major security challenges in information systems are detection of anomalous data patterns that reflect malicious intrusions into data storage systems and protection of data from malicious eavesdropping during data transmissions. The first problem typically involves design of statistical tests to identify data variations, and the second problem generally involves design of communication schemes to transmit data securely in the presence of malicious eavesdroppers. The main theme of this thesis is to exploit information theoretic and statistical tools to address the above two security issues in order to provide information theoretically provable security, i.e., anomaly detection with vanishing probability of …

Interactions Between Inflammatory Cells And Cocrmo Alloy Surfaces Under Simulated Inflammatory Conditions, Huiyu Shi

Dissertations - ALL

Metallic biomaterials continue to be the primary materials for medical devices because of their excellent physical and mechanical properties especially for certain implants which need high strength (hip, spinal, shoulder, knee etc.). However there is no perfect material to meet all the requirements of a medical device. Metallic biomaterials are prone to corrosion and wear which has been associated with implant failure (osteolysis, aseptic loosening, pseudo tumor etc.) This study focused on investigating how inflammatory cells interact with CoCrMo alloy surfaces under simulated inflammatory conditions (H2O2 treatment). It is hypothesized that the presence of Reactive Oxygen Species (ROS) in cell …

Statistical Learning Tools With Food Science, Jessica C. Hacker

Industrial Engineering Undergraduate Honors Theses

The food science discipline has many issues requiring research within academia in order to protect the food that gets distributed from industry. The team within the Center for Food Safety at the University of Arkansas’ Division of Agriculture has been studying the gastrointestinal microbial community in broiler chickens in order to control pathogenic bacteria and improve gut health within the chickens to promote a healthy adult microbiota. This has many positive effects on the quality of the chickens. The team performs a standard method of analysis on every experiment run within a software called QIIME to determine if a treatment …

Developing A Risk Analysis Model To Improve Study Abroad Awareness, Tyler Spain

Industrial Engineering Undergraduate Honors Theses

As international education opportunities increase in popularity among U.S. college students (McMurtrie, 2007), it is becoming more and more necessary for study abroad organizations to be aware of the risks students face as they travel abroad. While some international cities are riskier than others, it can be difficult to distinguish between cities which truly carry a high degree of risk for visiting students, and which cities are only perceived to be risky based on various personal misconceptions. The University of Arkansas Office of Study Abroad & International Exchange currently lacks a way to quantifiably analyze the risk of study abroad …

Statistical Behavior Of Distributed Microgrids With Cascading Model Predictive Control, Yasser Yasaei

Electrical and Computer Engineering ETDs

The problem of integration of distributed energy resources into the grid is addressed in this study. The main objective is to deploy such resources as an alternative for conventional resources in a power system, and to increase renewable resources share in the generationmix. Distributed energy resources in general come with small capacities, and may have an intermittent nature. The former characteristic limits their impact on large scale grid applications, while the latter characteristic can induce serious stability problems in the system. As the first step, an appropriate model is developed to mathematically describe the behavior of such resources and to …

Microspine Gripping Mechanism For Asteroid Capture, Ezekiel G. Merriam, Andrew B. Berg, Andrew Willig, Aaron Parness, Tim Frey, Larry L. Howell

Student Works

This paper details the development and early testing of a compliant suspension for a microspine gripper device for asteroid capture or micro-gravity percussive drilling. The microspine gripper architecture is reviewed, and a proposed microspine suspension design is presented and discussed. Prototyping methods are discussed, as well as testing methods and results. A path forward is identified from the results of the testing completed thus far. Key findings include: the microspine concept has been established as a valid architecture and the compliant suspension exhibits the desired stiffness characteristics for good gripping behavior. These developments will aid in developing the capability to …

Numerical And Analytical Modeling To Determine Performance Trade-Offs In Hydrogel-Based Ph Sensors, Piyush Dak, Muhammad Ashraful Alam

Birck and NCN Publications

Hydrogel based pH sensors are promising candidates for implantable sensors due to their low-cost and biocompatibility. Despite their commercial potential and numerous theoretical/experimental reports, the trade-offs between different performance parameters are not well understood, and explicitly stated. In this work, we develop a numerical and analytical framework to show that there is a fundamental trade-off between the performance parameters i.e. sensitivity/dynamic range vs. response-time/response-asymmetry in hydrogel sensors under constrained swelling conditions. Specifically, we consider the effect of the gel parameters, such as the ionizable group density ( N_f) and its dissociation constant ( K_a), on the …

Deontological Ethical System For Google's Self-Driving Car, Edgard Alejandro Arroliga Jr.

Computer Science and Software Engineering

Google's Self-Driving Car is a revolutionary product that is riddled with ethical conundrums. It is able to accurately scan and drive through densely populated roads without much difficulty. However, there are some situations where the car will likely have to make decisions that affect, maybe even take, the lives of those on the road. Issues such as the Trolley Problem and the Rear-End Dilemma describe situations where there seems to be no single ethical answer as to how the car should act. In order to solve these issues, I propose that a Deontological Ethical System should be implemented because it …

Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds, Jakob Hockman

Biomedical Engineering Undergraduate Honors Theses

Metallic single-walled carbon nanotubes (m-SWNTs) were separated from pristine SWNTs using affinity chromatography for use in electrically conductive tissue engineering scaffolds. Approximately one third of SWNTs have metallic properties. Separations were achieved using a protocol modified from Liu & coworkers (2011) in order to improve the method for cell culture environments. Samples enriched in m-SWNTs were isolated and characterized. However, challenges still remain for the complete separation of m-SWNTs from their semiconducting counterpart (s-SWNTs) using this protocol. Approaches to improve separation and reduce the difficulties associated with processing the nanotubes were suggested. One of the ultimate destinations of these nanotubes …

A System Dynamics Approach Applied To Wind Energy System Sustainability, Jenny Maria Tejeda Carlos

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Sustainability of energy systems is one of the most important challenges currently facing humanity. Access to energy is critical to ensure economic and social development of a nation (UNDP et al., 2000); however, extraction, production and consumption of energy resources are also associated with high volumes of greenhouse gas (GHG) emissions, environmental damage and, in some cases, adverse health effects in communities where energy facilities are located. Renewable energy sources have been considered as an alternative to traditional energy sources to meet energy demand in a sustainable manner (Del Rio and Burguillo, 2008). Wind energy is considered to be one …

Dynamic Constraint Optimal Selection Techniques For Linear Programming, Alireza Noroziroshan

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Linear programming has been studied for over 60 years. It has been considered as one of the most valuable optimization tool for many industrial problems. The simplex algorithm remains the predominant approach to solving linear programming problems. Here we use the simplex method in an active-set frame work to improve it substantially. In general an active-set method obtains solutions by adding one or more problem constraints at a time to solve smaller problems iteratively. In particular, some of these methods have proven to perform significantly faster than the simplex method. In this dissertation we proposed an e?cient constraint selection metric …

Optimization Of Heterogeneous Wireless Networks With Massive Mimo, Shitong Yuan

Electrical Engineering Dissertations - Archive

In the next generation wireless communication system, multi-layers of Heterogeneous Networks (HetNets) are required to provide high efficiency bandwidth usage and high speed data throughput. Users’ distribution and their quality of service (QoS) request are random, and the number of users may vary through the time. In order to deal with this problem, this thesis builds two games’ models to optimize the resource allocation corresponding to different situations in the first chapter. The spectrum efficiency is analyzed and compared between two games. By playing those games, cells can serve more users inside one cell, and all users are fair to …

Hdr Video Compression Using H.265 (Hevc) Main 10 Profile, Srikanth Vasireddy

Electrical Engineering Theses - Archive

Increasing the resolution of the video has been the main interest in the television industry for a long time. More recently the industry is studying techniques to increase the range of luminance and color representation in videos. This is achieved through High Dynamic Range/ Wide Color Gamut (HDR/WCG) videos by providing visual quality of experience to the end consumers close to that of real life compared to the Standard Dynamic Range (SDR) videos.In order to deliver high-quality video services to consumers, efficient compression techniques are required to store or transmit a video especially for high resolution video formats whilst maintaining …

Improved Similarity Measures For American Sign Language Recognition Using Manual Handshapes And Hand Appearances, Siddhartha Goutham Swaminathan

Electrical Engineering Theses - Archive

American sign language is a primary language for approximately 0.5 to 2 million people who are deaf or hard of hearing in the United States[22][23]. When a user encounters an English word which he does not understand, he looks up the meaning for it in a dictionary. However, when an American Sign Language (ASL) user encounters an unknown sign, looking up the meaning of that sign is not an easy task. There are many systems available to access ASL signs that require articulatory properties such as handshapes but these systems fail if there is a slight variation of what the …

Multilayer Perceptron With Adaptive Activation Functions, Chinmay Appa Rane

Electrical Engineering Theses - Archive

A Multilayer perceptron typically has a fixed nonlinear activation function for each hidden unit. In this thesis, an adaptive activation function for individual hidden unit is designed, where the network learns these activation functions at every iteration using a modern second order algorithm. Methods and algorithms for these adaptive activation functions along with several other techniques for training a multilayer perceptron’s weights are discussed. Comparisons between a multilayer perceptron with sigmoidal activation functions and a multilayer perceptron with piecewise linear activation functions are also discussed. The common activation function used is the sigmoidal activations, but it is still not proven …

Multi-Stage Enhancement Scheme For Low Quality Fingerprint Images, Ramakrishna Vighna Venkata Lanka

Electrical Engineering Theses - Archive

Security and authentication go hand in hand in today’s internet age. The population growth and increase in web-based services have posed a substantial risk of identity theft and fraud. The need for reliable authentication to protect one’s belongings has become essential. The goal of such an authentication system is to recognize a person by validating his/her identity. The traditional identity management systems which validate on the basis of knowledge and tokens such as passwords and identity cards are susceptible to theft and duplication. Hence these systems cannot suffice for reliable identity management. Biometrics on the other hand validate an individual …

Reversible Data Hiding Using Histogram Shifting, Sai Saketh Nandagiri

Electrical Engineering Theses - Archive

With the current state-of-the-art technology, intruders can easily gain access to sensitive information. To avoid this, different methods with improved security to hide information have been developed like, covert channels, hiding data in images, null ciphers, etc. The focus of this work is to enhance the security and data hiding capacity of the current state-of-the-art reversible data hiding algorithms. The proposed data hiding method is designed such that the original image is losslessly restored after extraction of a payload. The proposed framework allows embedding of a binary bit stream into the host or cover image while retaining the quality of …

Future Of Jpeg Xt: Privacy And Security, Maitri Shah

Electrical Engineering Theses - Archive

JPEG is de facto the most important and popular image format since 1992 which provides compressed images to a great extent. JPEG XT, the latest standardization of the JPEG committee, provides some amazing features like: backwards compatibility, support for High Dynamic Range (HDR), lossless and near-lossless coding, and alpha channel coding, which were not provided by the previous JPEG standards. With the increase in the demand for photos- capturing, sharing, editing- privacy concerns have become the primary issue. Leakage of private photos to unauthorized users is unacceptable and hence the need for protecting and developing an algorithm to maintain the …

Compression Artifact Reduction In Hevc Using Adaptive Bilateral Filter, Rohith Reddy Etikala

Electrical Engineering Theses - Archive

The High Efficiency Video Coding (HEVC) [8] is the latest video standard developed by Joint Collaborative Team on Video Coding (JCT-VC), a group of video coding experts from ITU-T Video Coding Experts Group and ISO/IEC Moving Picture Experts Group (MPEG). As the demand for HD video (4K and 8K) increased, there is a need for higher coding efficiency than H.264/AVC. Also, there is increased use of parallel processors. So, HEVC [8] has been introduced to support increased video resolution and parallel processing. HEVC obtains about 50% reduction in bit rate when compared to its predecessor H.264/AVC at the same visual …

A Switched Capacitor Based Transimpedance Amplifier For Detection Of Hab Through Optical Sensing, Uthra Mahendran

Electrical Engineering Theses - Archive

In the recent years, there has been a substantial increase in the manifestation of harmful algal blooms. A certain species called cyanobacteria that is commonly present in freshwater bodies are found to release a class of deadly toxins known as microcystin. This toxin poses a threat to humans and wildlife since they can cause severe illness or even death on consumption of contaminated water. Traditional sampling methods are essentially lab based detection methods that are inconvenient and demands extensive manual effort. Hence, large-scale occurrence of harmful blooms in water resources demands the development of efficient and reliable methods for monitoring …

Comparison Of Different Metals As Electrodes For A Flexible Micro Ph Sensor, Pavan Kumar Kota

Electrical Engineering Theses - Archive

pH can be explained in general terms as a numerical scale used to state the acidity or basicity of an aqueous solution. Keeping track of pH is very useful in many applications like medicine, civil engineering, chemical engineering, biology, water purification etc. Most commonly used pH sensors employ glass electrodes but there are some disadvantages associated with these kinds of pH sensors. Glass is a rigid, chemically reactive and fragile material. Also, glass electrodes, owing to the size require significant quantity of solution to test for pH which makes it difficult to use in cases where we have very little …

Analysis Of Shock-Plugs In Quasi-One-Dimensional Compressible Flow, Matthew Alexander Thompson

Graduate Theses - Mechanical Engineering

At small length scales, such as in micro-nozzles, the assumption that a shock wave is infinitesimally thin breaks-down due to the thickness of the shock being non-negligible compared to the dimensions of the nozzle. In this thesis, shock waves of finite thickness, or “shock-plugs,” are modeled using the same methods and assumptions as a standard shock wave analysis. Due to the finite thickness of shock-plugs, however, two additional parameters are required in order to account for the differing inlet and exit areas, as well as the pressure on the side walls of the channel. A “typical” micro-nozzle with appropriate dimensions …

Developing A Logistics Risk Assessment Tool, Daniel C. Fritsche

Industrial Engineering Undergraduate Honors Theses

Economies around the world have thrived in the wake of the development and keen understanding of effective supply chain management practices. As a result, organizations have become more dependent on other organizations to move their products and services to completion due to complex sourcing and shipping arrangements that have precipitated from the formation of sophisticated supply chains. A supply chain is in general a flow of products or services. When this flow is disrupted or halted, disastrous consequences can ensue. In the worst cases, such as with a disaster relief organization like the American Red Cross, disruptions in supply chains …

Engineered Resilient Systems Model Applied To Network Design, Zephan W. Wade

Industrial Engineering Undergraduate Honors Theses

Engineered Resilient Systems (ERS) is a Department of Defense (DoD) program focusing on the effective and efficient design and development of resilient complex engineered systems throughout their lifecycle. There is growing literature with qualitative definitions of resilience and quantitative models for systems, but these focus typically on systems with one performance measure. In application, many systems have multiple functions and multiple performance measures. This research uses a quantitative resilience framework for ERS that includes system design options, reliability, external threats, vulnerabilities, responses, and consequences assessed on multiple system performance measures. This paper applies the ERS framework to designing resilient networks.

A Dj Robot, Robert Hure, Josh King

Mechatronics Final Projects

This report discusses the design of an audio entertainment device incorporating movement, lights, and motion in order to entertain the user, shown in Fig. 1. The user inserts a source of music through an AUX cord, which controls the color of the lights display based on the frequency of music. Through a control box tethered to the device, shown in Fig. 2, the user controls the amplitude of rotary motion the lights move before returning back to its original position and repeating, which is controlled by a stepper motor. The user also has control of which color represents the bass, …

Sustainability Assessment Of Recycled Asphalt Mixtures In Texas, Reza Saeedzadeh

Civil Engineering Dissertations - Archive

The pavement practitioners use more recycled materials in asphalt mixtures in order to compensate for the high price of petroleum products and save the limited resources of virgin materials. Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) have been in wide use in asphalt mixtures for several decades. Public perception on the utilization of recycled materials is that the mixtures become more cost effective and more environmental friendly. This is true when the initial stage of construction of pavements is assessed. However, a mixture that costs less and/or burdens the environment less at the beginning may require more frequent …

Synergistic Timing Speculation For Multi-Threaded Programs, Atif Yasin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Timing speculation is a promising approach to increase the processor performance and energy efficiency. Under timing speculation, an integrated circuit is allowed to operate at a speed faster than the rated speed specified by its vendor. However, doing so might result in an incorrect execution. Consequently, as long as the processor is equipped with an error detection and recovery mechanism, its performance can be increased and/or energy consumption reduced beyond that achievable by any other conventional operation.

While many past works have dealt with timing speculation within a single core, in this work, a new direction is being uncovered by …