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Title: INDEX CODING VIA RANK MINIMIZATION
Creator: Huang, Xiao
Date: 2015, 2015-07
Description: Index codes reduce the number of bits broadcast by a wireless transmitter to a number of receivers with different demands and with side...
Show moreIndex codes reduce the number of bits broadcast by a wireless transmitter to a number of receivers with different demands and with side information. It is known that the problem of finding optimal linear index codes is NP-hard (a worst-case result). Many heuristic solutions based on graph coloring have been proposed. However, graph coloring is also a NP-hard problem, and it only gives an upper bound of the index coding. Motivated by a connection between index coding and rank minimization, this thesis investigates the performance of different heuristics based on rank minimization and matrix completion methods, such as alternating projections and alternating minimization, for constructing linear index codes over the reals. The underlying matrices representing an index coding problem have a special structure that makes celebrated methods, such as nuclear norm minimization, perform badly. The performance of different methods, such as alternating projections, directional alternating projections and alternating minimization are presented, through extensive simulation results on random instances of the index coding problem. This thesis makes the following contributions: 1) The proposed alternating projections method gives the best performance compared to other graph based algorithms in the literature. 2) This proposed method leads to up to 13% savings on average communication cost compared to the well know greedy graph coloring algorithm. 3) The thesis describes how the proposed methods can be used to construct linear network codes for non-multicast networks. Our computer code is available online.
M.S. in Electrical Engineering, July 2015
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Title: MODELING THE IMPACT OF NATURAL GAS VARIATION ON COMBUSTION IN A DUAL FUEL ENGINE
Creator: Hulbert, Matthew Calvin
Date: 2017, 2017-07
Description: The desire to meet rising energy demands while simultaneously adhering to stringent climate policies have propelled several advanced...
Show moreThe desire to meet rising energy demands while simultaneously adhering to stringent climate policies have propelled several advanced combustion technologies. The utilization of alternative fuels in internal combustion engines is a relevant solution to the immediate problems facing the transportation sector. Natural gas (NG) is an attractive alternative as it is economically and environmentally versatile, geographically diverse, and has clean-burning qualities which when coupled with dual fuel technologies has shown significant positive impacts on combustion characteristics. The present work describes the setup of an experimental test cell that contains a modern 2.0-liter 4-cylinder turbocharged direct-injected diesel engine that will be modified for dual fuel capability. The initial stages of a computationally efficient simulation model that represents the experimental engine are also presented and a discussion on the model’s development ensues. A dual fuel simulation model was created and calibrated against experimental data obtained from a heavy-duty 6-cylinder duel fuel engine. The objective of this work is to assess the affects different NG compositions have on the combustion process. Natural gas has shown to vary significantly, depending on where the fuel is acquired. The results show that methane content plays a significant role on combustion. As methane content increases, start of combustion (SOC) shifts and peak cylinder pressure decreases. The premixed combustion phase is shown to increase with decreasing methane content, while the mixing-controlled combustion phase decreases. Nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO2) emissions have demonstrated to be dependent on methane content. NG compositions with low methane content show increased amounts of CO2 emissions while high methane content shows a decrease in nitric oxide (NO) emissions.
M.S. in Mechanical and Aerospace Engineering, July 2017
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Title: TEXT MESSAGE REMINDERS AND TREATMENT ADHERENCE IN A TYPE II DIABETES POPULATION: A FEASIBILITY STUDY
Creator: Kramer, Alexis J.
Date: 2014, 2014-05
Description: Type II Diabetes (T2DM) is a chronic disease effecting millions of people worldwide. It is well documented that lifestyle changes including...
Show moreType II Diabetes (T2DM) is a chronic disease effecting millions of people worldwide. It is well documented that lifestyle changes including adherence to treatment regimens (e.g. glucose monitoring) can be very effective in reducing the onset and progression of T2DM. The literature suggests that individuals within this population are often non-compliant with treatment recommendations, for a variety of reasons (e.g. psychological factors, availability of resources, co-morbid conditions). The purpose of this study was to investigate the suitability, recruitment and retention feasibility, and preliminary outcomes of a text message reminder system on treatment adherence within a type 2 diabetic population, as measured by blood glucose levels (HbA1c). A total of 28 participants were randomized into experimental or no-treatment conditions. Participants in the experimental group received text message reminders on either a fixed or variable schedule; with either neutral or calming test message content. They also completed a qualitative feedback measure, to assess participant satisfaction with the proposed intervention. Participants in the no-treatment condition did not receive any text message reminders. All participants completed the Diabetes Care Profile (DCP) and Short Form-36 Health Form Survey, Version 2 (SF-36v2) at baseline and three months later (time 2). Preliminary analyses show that frequency of text message reminder significantly impacted glucose levels over time. The content of the text message was not shown to have a significant effect on glucose levels. Participant perception of the proposed intervention was mixed. Despite diverse recruitment efforts, recruitment was low, however, retention was high.
PH.D in Psychology, May 2014
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Title: SHARED LEADERSHIP EFFECTIVNESS IN FACE-TO-FACE AND VIRTUAL CONDITIONS: A SOCIAL NETWORK ANALYSIS
Creator: King, Adrienne
Date: 2013, 2013-12
Description: The purpose of this study was to investigate the relationship between shared leadership, performance, and team affect across two communication...
Show moreThe purpose of this study was to investigate the relationship between shared leadership, performance, and team affect across two communication-medium conditions: face-to-face and virtual interactions. After completing the “Lost-at-Sea” (Nemiroff & Pasmore, 1975) exercise, undergraduate students in leaderless teams (N = 75) of three reported their experiences and evaluated team members’ interactions and behaviors. Based on the functional leadership theory (McGrath, 1962), shared leadership was described by task and socio-emotional behaviors, and measured through social network analysis. Regression analysis revealed shared leadership’s positive influence on group affect and the condition’s impact on objective standards of performance. A follow-up mediational analysis revealed that team affect had a significant impact on the relationship between shared leadership and decision time. Additionally, post hoc analysis revealed that the level of shared leadership was higher in face-to-face teams, compared to teams in the computer-mediated condition. A discussion of the results and implications for practice are provided. In conclusion, this study highlights the importance of using shared leadership teams in modern organizations.
M.S. in Industrial / Organizational Psychology, December 2013
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Title: THE EFFECT OF NANOPARTICLE SELF-STRUCTURING ON WETTING AND SPREADING OF NANOFLUIDS ON SOLID SURFACES
Creator: Kondiparty, Kirtiprakash
Date: 2011-11, 2011-12
Description: Nanofluids are suspensions of nanometer-sized particles in liquids. The nanoparticles self-structure at the three-phase contact region...
Show moreNanofluids are suspensions of nanometer-sized particles in liquids. The nanoparticles self-structure at the three-phase contact region resulting in the structural disjoining pressure gradient which causes enhanced the spreading of nanofluids compared to simple fluids without nanoparticles. In this thesis, we attempt to understand the effect of the structural disjoining pressure on the spreading dynamics of nanofluids on solid surfaces. We observed nanoparticle self-structuring phenomena during film thinning on a smooth hydrophilic glass surface using a silica-nanoparticle aqueous suspension and reflected light interferometry. Our experiments revealed that film formed from small drop is thicker and contains more particle layers than a film formed from large drop. The data for the film-meniscus contact angle verses film thickness were obtained and used to calculate the structural energy isotherm of an asymmetric film. We studied the effect of structural disjoining pressure on the wedge meniscus profile formed by an oil drop on solid surface surrounded by nanofluid using Laplace Equation augmented with the structural disjoining pressure. Our analyses indicate that a suitable combination of the nanoparticle concentration, nanoparticle size, contact angle, and capillary pressure can result not only in the displacement of the three-phase contact line, but also in the spontaneous spreading of the nanofluid as a film on solid surface. We validated our theoretical predictions using experiments where we observed spreading of nanofluid on glass surface displacing a sessile drop of canola oil. The dynamic spreading of the nanofluid on a solid surface between a sessile oil drop on solid surface was experimentally measured using reflected light microscopy. We xiv obtained the rate of nanofluid spreading by plotting the position of the inner contact line with time. The nanofluid film was found to spread at a constant velocity. We modeled the spreading dynamics of the nanofluid film using the lubrication approximation of the Navier-Stokes Equation, taking into consideration the structural disjoining pressure in the over-all pressure balance. The model was evaluated by estimating the rate of nanofluid spreading for the 10v% nanofluid. The rate of spreading thus predicted by the dynamics model for 10v% nanofluid was in good agreement with the experimental observations.
Ph.D. in Chemical Engineering, December 2011
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Title: INVESTIGATING THE IMPACT OF EDUCATION AND CONTACT-BASED ANTI-STIGMA INTERVENTIONS ON THE STIGMA OF MENTAL ILLNESS IN THE COLLEGE POPULATION
Creator: Kosyluk, Kristin
Date: 2014, 2014-12
Description: Approximately one in four college students screen positive for a mental illness, however many who might benefit from mental health care do not...
Show moreApproximately one in four college students screen positive for a mental illness, however many who might benefit from mental health care do not seek treatment. Amongst both the general adult population and college students, stigma has been shown to be a predictor of treatment engagement, with higher levels of stigma with regard to mental illness predicting lower levels of treatment utilization. It has been demonstrated in the general adult population that contact-based anti-stigma programs are the most effective approach to stigma change, followed by education-based programs. This study aimed to investigate the impact of contact- and education-based anti-stigma interventions, relative to a control condition, on mental illness stigma, affirming attitudes towards individuals with mental illness, discrimination towards individuals with mental illness, and treatment seeking amongst college students. Both contact- and education-based interventions were found to have a significant impact on personal stigma, perceptions of empowerment, desired social distance from individuals with mental illness (a proxy of discrimination), attitudes towards treatment seeking, and intentions to seek treatment from formal sources of support. No difference in effect was demonstrated between the contact- and education-based conditions. These findings suggest that these two approaches may be equally effective for challenging stigma amongst college students.
Ph.D. in Psychology, December 2014
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Title: NEUROPATHOLOGIC CORRELATES OF BRAIN MACROSTRUCTURE
Creator: Kotrotsou, Aikaterini
Date: 2014, 2014-07
Description: Alzheimer’s disease, the most common form of dementia, is a degenerative disorder of the brain that leads to memory loss. Clinical diagnostic...
Show moreAlzheimer’s disease, the most common form of dementia, is a degenerative disorder of the brain that leads to memory loss. Clinical diagnostic techniques in use today rely on mental and behavioral tests and physical examinations and only provide diagnoses of possible or probable Alzheimer’s disease. However, lately it has become clear that clinical-pathological correspondence is not always consistent. A definitive diagnosis of Alzheimer’s disease is only possible via histology, when the density of neurofibrillary tangles and amyloid plaques is measured. Therefore, the development of a reliable neuroimaging technique that allows detection of Alzheimer’s pathology during life is needed. This method would be noninvasive, and could allow the detection of Alzheimer’s disease in the early stages, and could be also used to monitor the progression of the disease through time. The purpose of this work was to investigate the use of magnetic resonance imaging (MRI) as diagnostic tool for Alzheimer’s pathology and other age-related neurodegenerative pathologies that are common in older persons. To uncover the anatomical origins and determine the macrostructural signatures of age-related neuropathologies, it is necessary to link MRI findings with pathologic information on the same individuals. In this work, we focused on imaging cerebral hemispheres ex-vivo, when a complete pathology report was available from a board-certified neuropathologist. The main difference between this work and any other study is the abundance of postmortem imaging data paired with neuropathology data in a relatively large pool of subjects. First, we developed and validated a protocol to perform ex-vivo MR volumetry. By using this protocol we observed the longitudinal behavior of the volume of different brain regions. Furthermore, we tested the hypothesis that volumetric measurements performed ex-vivo are associated with in-vivo measurements. It was shown that: (a) regional brain volumes measured with this approach for ex-vivo MR volumetry remain relatively unchanged for a period of 6 months postmortem, and (b) a linear correspondence was detected between in-vivo and ex-vivo measurements, suggesting that this approach captures information linked to antemortem macrostructural brain characteristics. Using the approach for ex-vivo MR volumetry, we combined ex-vivo MR volumetry with pathology on the same adults. AD pathology was significantly negatively correlated with volumes of cortical gray matter regions, mainly in the temporal, frontal, parietal and cingulate cortices, subcortical gray matter, and whole-hemisphere white matter. A significant negative correlation was shown between hippocampal sclerosis and volumes of the hippocampus, as well as other temporal and frontal gray matter regions. Finally, we performed a morphometric MRI study to investigate associations of brain volumes with pathology using voxel-based analysis. This technique allows the assessment of gray and white matter volumes in subjects with different pathologies compared with controls in an automated fashion, across the whole brain. AD pathology was negatively associated with regions of gray matter and white matter located in temporal and frontal lobes, and orbitofrontal cortex. This work examined the associations of brain volumes with Alzheimer’s pathology and other typed of age-related neurodegenerative pathologies. Combining histological result with MR images requires that the time elapsed between imaging and histology is minimal. Ex-vivo MRI provides images at essentially the same time-point as histological examination of the tissue, and this study is unique in that it involves a large number of cadaveric brain hemispheres. The findings of this ex-vivo study could allow for future standardization of MRI as a biomarker of neurodegenerative diseases, and also allow in identification and classification of subjects in groups for tests of new drugs.
Ph.D. in Biomedical Engineering, July 2014
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Title: MODERATING EFFECT OF MINDFULNESS IN THE RELATIONSHIP BETWEEN CARDIOVASCULAR DISEASE RISK FACTORS
Creator: Kim, Jeong Hye
Date: 2016, 2016-07
Description: Cardiovascular diseases (CVDs) are the leading cause of death worldwide and in the United States. Weight loss, which is associated with blood...
Show moreCardiovascular diseases (CVDs) are the leading cause of death worldwide and in the United States. Weight loss, which is associated with blood pressure and blood glucose, is widely recommended to modify the CVDs risk factors. Among various methods, mindfulness has been extensively studied in improving psychological and physical health. There is some reported evidence that mindfulness based interventions are effective in improving CVDs risk factors. However, overall results are inconclusive. Therefore, more research examining the facets of mindfulness is necessary to understand the fundamental relationship between mindfulness and CVDs risk factors to clarify the effect of mindfulness. In addition, research into whether the relationship between different risk factors is moderated by mindfulness would provide further support of the independent effect of mindfulness on physical health. The current study hypothesized that higher mindfulness skills would correlate with physical well-being. Furthermore, it was hypothesized that mindfulness will moderate a relationship between BMI and other CVDs risk factors (e.g., individuals with higher BMI classification and higher mindfulness will show lower blood pressure compared to individuals at a similar BMI with lower mindfulness). Results found that body adiposity had an inverse relationship with overall mindfulness, and two of the four facets of mindfulness (Describing and Acting with awareness). In addition, the Describing subscale had a significant moderating effect; however, the relationship between body adiposity and systolic blood pressure was stronger rather than weaker with higher Describing skills.
M.S. in Psychology, July 2016
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Title: DEVELOPMENT OF ADVANCED PACKAGING, FABRICATION AND RELIABILITY METHODS FOR SUBMINIATURE IMPLANTABLE NEURAL PROSTHESES
Creator: Kim, Taehyung
Date: 2011-08, 2011-07
Description: The main purpose of the present thesis is to study the critical reliability issues of polymeric encapsulated electronic devices for visual...
Show moreThe main purpose of the present thesis is to study the critical reliability issues of polymeric encapsulated electronic devices for visual prosthesis. Visual prosthesis has been compatibly studied over twenty years in many professional research labs. The electric design of circuit for the visual prosthesis has been well studied so far. However, the device packaging design and reliability have been not studied extensively. In particular, failure analysis and reliability using non-hermetic packaging for long lifetime visual prosthesis have been poorly studied. The first step of the research for this thesis was to create a mechanical design of a visual prosthesis prototype. The prototype device was created by fabricate a multi-layer structure consisting of electrodes, substrate, and integrated circuit chip with silicone encapsulated packaging. The interconnection between the chip and electrodes used Au wire and Al bonding pad. The prototype devices were tested in a liquid water. This water environment is not a common reliability test for commercial electronic packaging. Relative humidity testing is a common and widely used testing methods, but the visual prosthesis device cannot be applied to gas phase relative humidity testing due to the environment condition. Water absorption in polymeric material in the liquid water is higher than in the vapor water. After water penetrated interconnection interface, the Au-Al intermetallic compound becomes oxidized and generates bonding die open failure. From these unusual testing results, we were conformed the failure mechanism and predicted the lifetime using Au-Al imtermetallic growth pattern and oxidation. Additional discussions include transition metal ions in CSF to expect the other failure mechanisms. Wafer and packaging level xiii failure mechanisms by Cu and Fe ions are also discussed in this thesis. The end of this thesis discuss possible fabrication processing to protect overall external environment effects for polymeric packaging visual prosthesis. Overall this thesis study, which uses polymeric packaging electronic devices for bio-implant research, concluded that devices may not make good reliability devices in the CSF environment. The corrosion, oxidation and metallization on or in metal surfaces and interconnection interfaces should continually be studied to produce longer lasting electronic devices over 30 years. The reliability of the visual prosthesis has not been well studied in any other professional research labs, so this thesis may give or address some initial guidelines to help save time for the project decision in the future to develop advanced hermetic packaging for bioimplantable electronic devices.
Ph.D. in Materials Science and Engineering, July 2011
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Title: BLADE PITCH OPTIMIZATION METHODS FOR VERTICAL-AXIS WIND TURBINES
Creator: Kozak, Peter
Date: 2016, 2016-07
Description: Vertical-axis wind turbines (VAWTs) offer an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates...
Show moreVertical-axis wind turbines (VAWTs) offer an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates safety and noise concerns, potentially allowing for installation closer to populated and ecologically sensitive areas. While VAWTs do offer significant operational advantages, develop- ment has been hampered by the difficulty of modeling the aerodynamics involved, further complicated by their rotating geometry. This thesis presents results from a simulation of a baseline VAWT computed using Star-CCM+, a commercial nite volume (FVM) code. VAWT aerodynamics are shown to be dominated at low tip- speed ratios by dynamic stall phenomena and at high tip-speed ratios by wake-blade interactions. Several optimization techniques have been developed for the adjustment of blade pitch based on finite-volume simulations and streamtube models. The effectiveness of the optimization procedure is evaluated and the basic architecture for a feedback control system is proposed. Implementation of variable blade pitch is shown to increase a baseline turbine's power output between 40%-100%, depending on the optimization technique, improving the turbine's competitiveness when compared with a commercially-available horizontal-axis turbine.
Ph.D. in Aerospace and Mechanical Engineering, July 2016
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Title: EFFECTS OF UNSTEADY AERODYNAMICS ON VERTICAL-AXIS WIND TURBINE PERFORMANCE
Creator: Kozak, Peter
Date: 2014, 2014-05
Description: Vertical-axis wind turbines (VAWTs) o er an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates...
Show moreVertical-axis wind turbines (VAWTs) o er an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates safety and noise concerns. As a result, VAWTs can be used to open up more populated areas for large-scale wind energy development. While vertical-axis turbines do o er signi cant operational advantages, development has been hampered by the di culty of mod- eling the aerodynamics involved, along with their rotating geometry. This thesis presents results from a simulation of a baseline VAWT computed using Star-CCM+, a commercial nite volume (FVM) code. Overset grid techniques are used to model the VAWT's complex and moving geometry. VAWT aerodynamics are shown to be dominated at low tip-speed ratios by dynamic stall phenomena and at high tip-speed ratios by wake-blade interactions, using ow visualization and blade angle of attack. An iterative procedure to optimize the VAWT's geometry is developed using blade pitch to mitigate the adverse e ects of dynamic stall for a tip-speed ratio of 2.0 case. Relying on both a constant blade pitch o set as well as a variable blade pitch as a function of azimuthal angle, power output was shown to be increased by 17% and 38%, respectively, compared to the baseline case. Emphasis is placed on the modeling techniques used in the FVM simulation and the optimization process.
M.S. in Mechanical and Aerospace Engineering, May 2014
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Title: AN OPTIMIZATION OF MANUFACTURING PROCESS SELECTION THROUGH COSTING AND SYSTEMATIC ANALYSIS
Creator: Klima, Kevin
Date: 2017, 2017-05
Description: In order for any company to remain competitive, there is a constant push to cut costs while keeping customers satisfied by providing quality,...
Show moreIn order for any company to remain competitive, there is a constant push to cut costs while keeping customers satisfied by providing quality, robust products. While current methods for predicting the most cost effective manufacturing process have proven to offer a significant amount of utility for design engineers, the issue remains that for a cost estimation to be truly accurate, the component has to be completely or nearly completely designed, which could require a significant amount of upfront development time. The goal was to develop a design tool to predict the most cost effective process to manufacture a new component based solely on already available historical data and basic knowledge of the design requirements of the new part. This study focused on steel components that could be manufactured either as a fabrication or as a casting. Two real-world applications were studied from two separate industries, with each application being designed with each process. Common cost estimation techniques were used to develop models for predicting the cost for each component to offer insight for how the cost would be expected to vary with quantity. As a means of ensuring robustness and that each competing model was structurally equivalent, each model had to pass critical exceptional and fatigue load cases in FEA while also meeting predefined success criteria. Using the results from the structural analysis and cost estimation, a design tool was developed as a means of objectively predicting how a component with similar application requirements would most cost effectively be manufactured based on the desired quantity of parts that needed to be produced. By using historical information of similar components that have the possibility of being manufactured in more than one way, more effective and systematic decision making for how a new component should be manufactured was shown to be possible. A third, independent case study was also selected as a real world example from industry as a means of validating and assessing the sensitivity of the weighting used in the development of the design tool. This was used to further refine the tool for the use in analyzing future components.
M.S. in Manufacturing Engineering, May 2017
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Title: ASSESSMENT OF MICROGRIDS FOR DEVELOPED AND DEVELOPING COUNTRIES
Creator: Vyas, Kohil
Date: 2013, 2013-12
Description: Today’s world essentially runs on electricity, in some form or the other. From the introduction of the concept of electricity by William...
Show moreToday’s world essentially runs on electricity, in some form or the other. From the introduction of the concept of electricity by William Gilbert to thousands of invention by Thomas Edison, there have been great changes in the world of electricity. The life of every living being is directly affected by these changes. Various electrical problems have surfaced because of these changes. Microgrids have been considered as a solution to these problems, and have been assessed and evaluated in this research. To realize the effectiveness of microgrids as a solution, initially problems were explored. It was found that there are two perspectives of the problems faced by electrical world. One being: problems seen from the view point of developed countries, and the other: problems seen from the view point of developing countries. Assessment of microgrids was accordingly branched during the research. In the case of the developed countries, the basic infrastructure of electrical system which was built long ago, demands an upgrade now. Problems like blackouts and brownouts have risen and the frequency of their occurrence is growing with time. Owing to these problems, there has been a loss of billions of dollars, as well as critical loads like research facilities, military bases, data centers etc… are severely affected. Microgrids installed in military bases, a university campus and a jail were assessed to analyze how they are implemented, the benefits reaped from them and how they can be a viable solution to the problems faced by the developed countries. In the case of the developing countries, the fact stands that they are yet to reach a state where they can serve their entire load by themselves. This results into regular load shedding. Also, there are some areas where there is no electrical infrastructure and this restricts many from even having xi the access to the electricity. For this research, microgrids installed in villages of Africa, India, and on the islands of Maldives were assessed. Their application and revolutionary impacts on the developing countries were explored. The research indicates that in the developed countries, owing to the gargantuan increase in power consumption, several electrical problems have arisen. Microgrids were able to solve these problems and save millions of dollars. Whereas, in developing countries, people still are in need of a 24-hours access to electricity for their progress. Electricity is required for basic necessities like pumping water, cooking, and activities carried out at night which requires light. Implementation of microgrids by providing electricity removes the bottleneck to their progress.
M.S. in Electrical Engineering, December 2013
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Title: Ease of Contamination and Subsequent Sanitation of Food Contact Surfaces Using Salmonella Contaminated Nut Butters
Creator: Kamineni, Prashanthi
Date: 2012-07-23, 2012-07
Description: Salmonella species can survive and or persist for long periods of time in low moisture foods and on food contact surfaces. Understanding...
Show moreSalmonella species can survive and or persist for long periods of time in low moisture foods and on food contact surfaces. Understanding parameters of transfer and survival can provide information required for successful control of this foodborne microorganism. This study investigated the recovery of Salmonella from food contact surfaces (stainless steel, Delrin, polyethylene, polyurethane) as well as their transfer from nut butters onto the contact surfaces. S. Tennessee and S. Oranienburg were grown overnight to stationary phase, harvested and inoculated separately into peanut butter and almond butter. One gram of inoculated nut butter was applied to each of the three separate 4 X 4 cm areas on the materials and stored at room temperature. The nut butters were removed after 1, 7, and 14 day intervals to leave a visually clean surface. Surfaces were swabbed and/or tested with contact plates to determine the population of any remaining cells. Using contaminated peanut butter, highest numbers of S. Tennessee of about 4.27 ± 0.30 per cm2 were recovered from stainless steel surface after 1 day of contact time. Both serovars were recovered at low numbers over time. However, when contaminated almond butter was used, lower recovery was obtained with both serovars. Visually clean surfaces were also treated with various sanitizers to determine efficiency of treatments. Of the three sanitizers, isopropanol proved most effective overall in reducing Salmonella contamination whereas chlorine was least effective. BDD and isopropanol gave best efficiency on stainless steel with a reduction of about 2.5 logs and least on polyurethane surface with a reduction of only about 1 log (p<0.05). Results were similar for both the serovars tested. In general, sanitizers were most effective on stainless steel while polyurethane surface was the most difficult to sanitize. These studies contribute to a better understanding of the behavior of S. Tennessee and S. Oranienburg in nut butters and on food contact surfaces. Estimation of contamination levels may be determined from transfer rates for Salmonella from contaminated to uncontaminated foods and food contact surfaces.
M.S. in Food Safety and Technology, July 2012
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Title: IMPROVING PEDESTRIAN DETECTION USING OPTICAL FLOW
Creator: Kong, Lingxing
Date: 2015, 2015-12
Description: Pedestrian detection, which has wide applications on surveillance, automatic driving and robotics, plays a significant role in computer vision...
Show morePedestrian detection, which has wide applications on surveillance, automatic driving and robotics, plays a significant role in computer vision. Among all kinds of pedestrian detection methods, stereo based method achieves an accurate and efficient detection result by exploiting depth and color information. However, many stereo based systems fail at considering motion information which is important in locating and detecting an object. For many pedestrian detection systems, adding extra data like motion is one of the most effective ways to improve the performance. Therefore, this thesis proposes a multi-cue pedestrian detection system which integrates optical flow based and stereo based modules for combining motion, depth and color information. In the proposed system, optical flow and disparity value are estimated by using the frames which obtained from a stereo camera. In order to obtain accurate pedestrian motion, ego motion is compensated by using motion clustering, affine model and RANSAC. After that, the motion and the depth information are exploited for ROI generation. Finally, SVM is trained by the combination of motion feature and HOG feature. Experimental results show that the use of high-accuracy optical flow along with depth and color information improves the performance of multi-cue pedestrian detection system.
M.S. in Electrical Engineering, December 2015
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Title: NOVEL 8-T CNFET SRAM CELL DESIGN FOR FUTURE ULTRA-LOW POWER MICROELECTRONICS
Creator: Kim, Youngbae
Date: 2016, 2016-05
Description: In deep sub-micron technology, leakage power consumption has become a major concern in VLSI circuits, especially for SRAM, which is used to...
Show moreIn deep sub-micron technology, leakage power consumption has become a major concern in VLSI circuits, especially for SRAM, which is used to build the cache in System-on-Chip (SOC). In this paper, a low power 8-T SRAM cell, based on carbon nanotube field effect transistor (CNFET), is proposed to circumvent the leakage power issue. Experiment datas show that the proposed SRAM cell can save 97.94% static power consumption compared to existing 6T CNFET SRAM cell. In case of writing, the proposed SRAM cell consumes 39.27% less power than the traditional SRAM cell for writing 0 and 58.79% less for writing 1. Also, because of the adoption of a colaborated voltage sense amplifier and independent read component, our 8T SRAM shows much improved delay performance, the delay is observed to reduce by approximate 30% in write operation and approximate 90% in read operation.
M.S. in Electrical Engineering, May 2016
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Title: LIPID-LIPID AND LIPID-DRUG INTERACTIONS IN BIOLOGICAL MEMBRANES
Creator: Martynowycz, Michael W.
Date: 2016, 2016-07
Description: Interactions between lipids and drug molecules in biological membranes help govern proper biological function in organisms. The mechanisms...
Show moreInteractions between lipids and drug molecules in biological membranes help govern proper biological function in organisms. The mechanisms responsible for hydrophobic drug permeation remain elusive. Many small molecule drugs are hydrophobic. These drugs inhibit proteins in the cellular interior. The rise of antibiotic resistance in bacteria is thought to be caused by mutations in protein structure, changing drug kinetics to favor growth. However, small molecule drugs have been shown to have different mechanisms depending in the structure of the lipid membrane of the target cell. Biological membranes are investigated using Langmuir monolayers at the airliquid interface. These offer the highest level of control in the mimetic system and allow them to be investigated using complementary techniques. Langmuir isotherms and insertion assays are used to determine the area occupied by each lipid in the membrane and the change in area caused by the introduction of a drug molecule, respectively. Specular X-ray re ectivity is used to determine the electron density of the monolayer, and grazing incidence X-ray diffraction is used to determine the inplane order of the monolayer. These methods determine the affinity of the drug and the mechanism of action. Studies are presented on hydrophobic drugs with mammalian membrane mimics using warfarin along with modified analogues, called superwarfarins. Data shows that toxicity of these modified drugs are modulated by the membrane cholesterol content in cells; explaining several previously unexplained effects of the drugs. Membrane mimics of bacteria are investigated along with their interactions with a hydrophobic antibiotic, novobiocin. Data suggests that permeation of the drug is mediated by modifications to the membrane lipids, and completely ceases translocation under certain circumstances.
Ph.D. in Physics, July 2016
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Title: ACOUSTICAL ANALYSIS OF A SMALL PERFORMANCE HALL
Creator: Masoner, Ashley
Date: 2012-04-19, 2012-05
Description: This thesis studies the acoustics of a 793 seat multi-use theater. The theater is a fan shaped hall with acoustical properties that the...
Show moreThis thesis studies the acoustics of a 793 seat multi-use theater. The theater is a fan shaped hall with acoustical properties that the building owners found to be wanting. The acoustics were first measured using eight microphones and a frequency-sweepproducing source. The measured reverberations were then used to design and calibrate a model of the space in CATT, an acoustical modeling program, after which a variety of other unmeasured qualities of the space were calculated from the CATT model. This information was used to design a plan to improve the acoustics of the theater; the hall’s volume was increased by moving the back balcony wall farther back in order to increase the reverberation, the ceiling was reshaped in order to more evenly distribute the first order reflected rays to the audience, and some of the walls were resurfaced to alter the frequency effects of the walls. All these alterations are feasible from an engineering perspective. The proposed changes were then modeled in CATT to confirm they would have the desired effects.
M.S. in Civil Engineering, May 2012
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Title: 'BUILDING' SKINS: EVALUATION OF THE DESIGN PROCESS FOR ENERGY EFFICIENT GLASS FAÇADES
Creator: Muro, Maria Palencia
Date: 2011-05-09, 2011-05
Description: The main significance of this Thesis is reinforcing the importance of validating the design decisions for glass façades in order to improve...
Show moreThe main significance of this Thesis is reinforcing the importance of validating the design decisions for glass façades in order to improve their energy performance and achieve an optimum interior space comfort without compromising its ability to adapt to future needs. Since the influence of glass façades in energy consumption is widely known and proved, and environmental and user needs change with time, this research encourages the evaluation of glass-wall designs in order to ensure high performing building envelopes. The research consists of three main parts. First, in relation to glass façade design there has been an analysis of glass components and its effects, an identification of the façade requirements, and a study of the technology behind the glass enclosure. Second, there has been a numerical evaluation of different glass-wall systems; glazing types, window-towall ratio and screening devices have been simulated for heating, cooling and lighting loads using TRNSYSlite, and COMFEN respectively. The combination of these results along with the study of the SHGC, U-value, Tvis, incident solar radiation and energy transmission and conduction, has concluded in a catalogue of glass-wall systems suitable for each orientation. Third, the numerical results have been applied in the design of a glass enclosure for an existing building in Chicago. The overall results of this research provide criteria to design a residential glass enclosure in Chicago that can improve its performance today, and can also be adapted to meet future space and environmental needs. Hopefully, architects will be encouraged to numerically evaluate their design intentions to obtain energy efficient and adaptable glass-wall designs.
M.S. in Architecture, May 2011
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Title: THE RELATIONSHIP BETWEEN ATTRIBUTIONAL STYLE, DEPRESSION, AND ACCEPTANCE OF DISABILITY IN CHINESE INDIVIDUALS WITH SPINAL CORD INJURY
Creator: Heyne, Mark Michael
Date: 2011-03-27, 2011-05
Description: The positive relationship between negative attributional style and depression has been established in both those with and without chronic...
Show moreThe positive relationship between negative attributional style and depression has been established in both those with and without chronic illness or physical disability; however, this relationship remains uncharacterized in those with spinal cord injury (SCI), which is surprising, given this condition’s significant potential for negative psychosocial implications. Although there is evidence that the association among these two variables generalizes across cultures and disabilities, other findings suggests that the Chinese have a more negative attributional style than their Western counterparts, which could alter the relationship between attributional style and depression among Chinese with SCI. Likewise, the construct of acceptance of disability (AD) and its correlates has been covered extensively in Western samples with SCI, but has received virtually no attention in Eastern samples. The present study examined these variables within the context of SCI in a Chinese sample. Participants were 158 Chinese individuals with SCI who completed a battery of self-report measures of demographic, injury-related, and psychosocial variables. Cluster analysis results suggested three distinct clusters based on attributional style (positive, neutral, negative). Those in the positive attributional style cluster were more likely to have tetraplegia than paraplegia, but exhibited less functional disability and depressive symptoms, and higher AD than the negative cluster. Path analysis indicated that higher functional disability predicted both more negative attributional style and higher depressive symptomology; attributional style did not directly predict depression, in contrast to findings from previous studies. Higher depressive symptomology was found to predict lower AD, consistent with existing research.
Ph.D. in Psychology, May 2011
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