2017 UMKC Theses - Freely Available Online
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Item Modeling the hippocampus : finely controlled memory storage using spiking neurons(University of Missouri--Columbia, 2018) Hummos, Ali; Nair, Satish S.The hippocampus, an area in the temporal lobe of the mammalian brain, participates in the storage of personal memories and life events. As such traumatic memories and the consequent symptoms of post-traumatic stress are thought to be stored or at least processedin the hippocampus. While a fundamental understanding of a traumatic memory is still elusive, studying the physiology and functional properties of the hippocampus are anessential first step. Towards that goal, I developed a detailed computational model of the hippocampus. The model included the important effects of the neuromodulator Acetylcholine that switches the hippocampal network between the memory encoding state and the memory retrieval state. In the first study, I examined the mechanisms for controlling runaway excitation in the model. The results indicated different mechanisms for controlling runaway excitation in the memory encoding state as opposed to the memory retrieval state of the circuit. These findings produced the first functionally-based categorization of seizures in animals and humans, and may inspire specific treatments for these types of seizures. The second study examined the underpinnings of the rhythmic activity of the hippocampus. These oscillations in the theta range (4-12 Hz) are theorize to play a major role in the memory functions and in processing sequences of events and actions in both place and time. We found the generation of theta rhythmic activity to be best described as a product of multiple interacting generators. Importantly, we found differences in theta generation depending on the functional state of the hippocampus. Finally, the third study detailed the rules of the complex interactions between these multiple theta generators in the circuit. Our results shed more light on the role of specific components in the hippocampal circuit to maintain its function in both health and disease states.Item The Evaluation of Permeable Cementitious Media for Nutrient Removal(University of Missouri -- Kansas City, 2017) Ramsey, Andrew J.; Hart, Megan Leanore, 1976-Excessive amounts of nutrients in surface and ground waters can interfere with the quality of aquatic and human life. Permeable pavement systems have been studied for contaminant removal, but there are limitations to the current state of knowledge. Laboratory studies were utilized to fundamentally characterize permeable cementitious media for the removal of nitrate-nitrogen and orthophosphate-phosphorus. Batch reactor tests were used to determine nitrate and orthophosphate removal and retention for five permeable reactive concrete mixtures. Additionally, fixed-bed breakthrough experiments were used to determine the nitrate removal for five permeable lightweight cellular concrete mixtures. Finally, one breakthrough experiment was used to determine the nitrate removal of a lightweight cementitious media. It was determined that nitrate and orthophosphate removal isotherms of permeable reactive concrete were linear within the range of concentrations tested. The greatest nitrate removal in batch reactor and column tests were with ordinary portland cement (OPC), 50% replacement with ground-granulated blast-furnace slag, and 3% replacement with titanium dioxide (TiO2). OPC cellular concrete mixtures demonstrated beneficial removal at a lower w/c ratio. The nitrate removal process was characterized as slow for the cellular concrete and lightweight media mixtures during column tests. Multiple rates of nitrate removal observed during column testing may indicate multiple mechanisms of removal. Leach testing indicated that nitrate removal may not be permanent, although over 85% was retained by the TiO2 and OPC mixtures. Orthophosphate removal and retention was effective for all PRC specimen with greater removal for the mixtures containing 3% replacement with TiO2 and 25% replacement with fly ash. In addition to nutrient removal, correlations between nitrate removed and sulfate leached were investigated. It was determined that soluble sulfate slowly leaches from the hydrated concrete and foaming agent in all mixtures. Specimen that were flushed with deionized water experienced lower removal rates than their counterparts. No direct correlation between mass of sulfate leached and mass of nitrate removed was observed in batch reactor testing or cellular concrete tests, although supplementary materials and the foaming agent could affect the relationship.Item Next-Generation Flash Memories Using Two-Dimensional Materials(University of Missouri -- Kansas City, 2017) Shishupal, Hemanshu; Chowdhury, Masud H.This thesis presents a model that provides the output characteristics of next-generation flash memories using two-dimensional materials. Multi-Layer Graphene Nanoribbon (MLGNR) and Graphene are used as the channel and floating gate of the device proposed. The current in the channel is calculated using the Poisson-Schrodinger equation; the numerical algorithm is based on the Newton-Raphson (NR) method. A comparative study is done on two different Floating Gate Transistor (FGT) based on the proposed model. Silicon dioxide (SiO₂) and Hafnium dioxide (HfO₂) are the two oxides explored as the top control oxide of the device.Item Half and Half(University of Missouri -- Kansas City, 2017) Boyd, Colleen E.; Pritchett, Michael, 1961-This thesis is a collection of short stories that I wrote and rewrote between my time as an undergraduate at Knox College and my time as a graduate student at UMKC. These stories were picked over other fictional works because I believe they present the best display of my skills as a writer. Each story is meant to examine the human reaction in various situations, whether in real life or with a dash of something magical, and how they deal with what happens. The goal of this thesis was to collect all the experiences of the characters to deliver a range of moments the reader can identify with. The thesis is actually split in two regarding the type of stories in it. On one hand, you have literary fiction that examines the lives of regular adults and how they interact with the world. On the other hand, we have more ‘young adult’ fiction that touches on the going-ons of young people. The young adult may not be as ‘mature’ as the literary fiction, but regardless of the genre both sets of characters face real life problems that may not have the happiest solutions. As such, there is a sense of worry about what comes next throughout each piece. Yet to counter the fear is their want for things to be all right and how they work to achieve such peace. This collection is about that while pain and hardships are inevitable, you do have the ability to change and endure.Item Smart City Open Data Network System: Openness, Security, and Privacy(University of Missouri--Kansas City, 2017) Almansoori, Mohammed; Choi, Baek-YoungThe increasing concentration of population around the cities poses challenges in their operation and services. On the other hand, the current technological revolution allows scalable and innovative means to better serve the public. Many city governments are collecting, publishing and analyzing more data from diverse sources including IoT sensors. City government’s open data provides multiple values such as improving transparency of the government, enhancing the efficiency of its operations and services and attracting more businesses to the region. However, the resulting data systems, called Open Data Portals (ODPs) become more complicated and create the issues of accessibility, security, and privacy. Extensive analyses of ODPs of many cities around the world using diverse methodologies have been performed. We find that the extent of openness of data and popularity, and the level of security of ODPs are highly diverse across the cities. We then provide the recommendations for improving security measures of ODPs. Considering the privacy issues of data in ODPs, we provide a tool to automatically filtering Personally Identifiable Information (PII).