Master of Science, The Ohio State University, 2012, Geological Sciences

In 2011, Ohio State University began drilling wells for a geothermal heating and cooling system to upgrade several dormitories. The drillers encountered problems with collapsing boreholes and very high permeabilities at multiple depths within the Columbus Limestone, Salina Undifferentiated, and the Tymochtee and Greenfield dolomites. The driller reported two high permeability zones underlying the campus: one at 140-150 feet deep, and another at depths of 280 to 360 feet. The shallow zone corresponds to the depth of the Columbus Limestone and the deeper zone corresponds to the Salina Undifferentiated and the underlying dolomite units. The upper permeability zone coincides with the known cave zone within the Delaware and Columbus limestones, which house the Ohio Caverns and the Olentangy Indian Caverns. More in-depth study of this zone's characteristics through quarry visits and core description reveals traditional continental or epigenetic karst features such as flow channels, dissolution along bedding planes, and missing core. This paleokarst zone was created by groundwater flow at or just below the water table and is a form of epigenic karst. The depth of the lower permeable zone coincides with that of the Newburg Zone. Further study of the lower permeable zone based on core descriptions, quarry visits, geophysical logs, borehole video, and thin sections reveals evidence for extensive karstification in the form of vugs, dissolution chambers, enlarged fractures, spongerock, and missing core. The dissolution chambers are caves that have no evidence of flow passages leading in or out of them, suggesting that they are mixing chambers. These appear to be Silurian analogues to modern flank-margin caves that form on the flanks of carbonate islands where the fresh-water lens meets seawater. These flank-margin caves have been extensively described in tropical regions around the world. Based on the equatorial location of Ohio during the Late Silurian Period, the environmen (open full item for complete abstract)

Committee: E. Scott Bair PhD (Advisor); W. Berry Lyons PhD (Committee Member); William I. Ausich PhD (Committee Member) Subjects: Environmental Geology; Geology

Master of Sciences (Engineering), Case Western Reserve University, 2024, EMC - Aerospace Engineering

As deep space missions expand in scope and distance, the efficiency of propulsion systems becomes paramount. This thesis analyzes the impact of small measurement errors in the thrust profiles of Hall-Effect Thrusters, a common type of electric propulsor, known for increased efficiency compared to traditional chemical propulsion despite lower thrust. Due to their prolonged operational times, these errors compound, affecting trajectory and mission success. Through analyzing the AEPS Hall-Effect Thruster prototype, designed for NASA's Artemis Program's Gateway space station, using curve fitting and a Monte Carlo simulation, we assess the effects of these errors on an example mission to Alpha Centauri. Results show plasma dynamics cause the majority of error, but cause minimal trajectory deviation and propellant loss. This reinforces electric propulsion's suitability for long-distance space travel. This work informs spacecraft mission design, providing valuable insights into fuel efficiency and system selection, as well as building upon NASA Glenn Research Center's Electric Propulsion and Power Laboratory's prior research.

Committee: Bryan Schmidt (Committee Chair); John Yim (Other); Richard Bachmann (Committee Member); Paul Barnhart (Committee Member) Subjects: Aerospace Engineering; Engineering; Mechanical Engineering

Master of Science, The Ohio State University, 2023, Aero/Astro Engineering

The Parametric Flutter Margin (PFM) method is utilized to identify the aeroelastic characteristics of an Unmanned Aerial Vehicle's wing in a series of Ground Vibration Tests (GVTs) and initial flight-testing study. A self-contained electromechanical excitation system developed to excite and measure the resultant wing dynamics such that Frequency Response Functions (FRF) can be identified from recorded inertial data is detailed. The results of bench-top testing performed to characterize the purpose-built excitation pods is discussed. Specifically, ground-testing indicates that the excitation pod's instrumentation could accurately measure a perturbation force generated by a moving mass within 3% error of directly measured values. Further testing reveals that the excitation pod's instrumentation could measure the resultant wing acceleration response within 1 ms-2 error. A series of GVTs performed on various wing configurations demonstrate that the self-contained excitation pods generate a sufficiently powerful perturbation force to energize an elastic response. The structural modes experimentally identified through the excitation system and PFM estimation method closely match corresponding Finite Element Analysis (FEA) predictions. A flight-testing campaign was conducted to demonstrate the excitation system and PFM method in a free-flight environment. The results of this preliminary flight-test study indicate that the frequency characteristics associated with the flexible wing's symmetric and anti-symmetric modes can be identified. Initial flight-testing results reveal the importance of properly defining the excitation signals such that the symmetric and anti-symmetric forcing functions are of comparable magnitude. After identifying the phase-crossover frequencies from FRFs measured through flight-testing, a flutter margin versus airspeed curve is developed for both the wing's symmetric and anti-symmetric modes. From these curves, an anti-symmetric flutter mechanism wi (open full item for complete abstract)

Committee: Matthew McCrink (Advisor); Moti Karpel (Committee Member); Jack McNamara (Committee Member) Subjects: Aerospace Engineering; Engineering; Mechanical Engineering

Honors Theses, Ohio Dominican University, 2023, Honors Theses

Business is a vital part of American society, and the decisions made by businesses affect more than just the economy. Conscious Capitalism (CC) recognizes this important role, and it challenges businesses to operate in a responsible manner. That being said, CC understands the need to make a profit in order to succeed in a competitive market. This practice claims that by following four tenets of conscious business—conscious leadership, conscious culture, stakeholder orientation, and higher purpose—businesses attract customers and will experience increased profits over time. This study found that, while the gross profit margins of companies who practice CC were similar to those of their non-conscious counterparts on a year-to-year basis, CC companies did experience a greater increase in their gross profit margins over time.

Committee: Arlene Ramkissoon (Advisor); Edward Lukco (Other); Douglas Ruml (Other) Subjects: Business Administration; Business Education; Educational Leadership; Entrepreneurship

Master of Science, The Ohio State University, 2021, Earth Sciences

We interpret a region of undulatory sediments adjacent to a major headwall of the Cape Fear submarine landslide system offshore of North Carolina, USA, as sediment waves rather than creep or fault-related deformation. The wave package extends 19 kilometers upslope from the S4 landslide headwall and thickens upslope from approximately 250-450 m. Examination of the undulating sediments with seismic and bathymetry data reveals the undulations feature continuity of seismic horizons, upslope-migrating crests, downslope thinning, and wave heights and lengths of ~26 m and ~1 km, respectively, which are consistent with sediment wave fields. These waves may be related to the contourites of nearby Blake Ridge, formed by the Western Boundary Undercurrent. Nearby Ocean Drilling Program cores suggests that turbidity currents may have also played a role in wave formation. While most of the 19-km long field comprises unaltered sediment waves, we observe a ~5-km long zone adjacent to the landslide scarp containing evidence of faults that offset and deform the sediment wave strata. We interpret this deformation as the result of reduction in stress following the removal of the landslide mass. Given that the Cape Fear system has generated several episodes of potentially tsunamigenic slope failure, the future stability of the system is of interest. Redefining these undulatory sediments as sediment waves eliminates a major slope instability mechanism of the system and is important for understanding future slope stability hazards of Cape Fear. Our analysis highlights the importance of understanding sediment waves in hybrid submarine landslide-sediment wave systems.

Committee: Derek Sawyer (Advisor); Matthew Saltzman (Committee Member); W. Berry Lyons (Committee Member); Lawrence Krissek (Committee Member) Subjects: Geology; Geophysics; Marine Geology

Doctor of Philosophy, The Ohio State University, 2019, Statistics

Case influence and model complexity play very important roles in model diagnostics and model comparison. They have been extensively studied in linear regression and generalized linear model (GLM). In this dissertation, we focus on how to assess case influence and estimate model complexity for penalized M-estimators with non-smooth loss functions in regression and classification. Cook's distance is commonly used for case influence assessment in least squares regression. It measures the overall change in the fitted model when one case is deleted from the data. Unlike least squares regression, however, the relation between the full-data solution and leave-one-out (LOO) solution is not explicit for general penalized M-estimators, which makes the computation challenging. We propose a new algorithm to relate the full-data solution with the LOO solution through a case-weight adjusted solution path. We take penalized quantile regression and support vector machine (SVM) as an example in regression and classification, respectively. Resorting to the homotopy technique in optimization, we introduce a case weight for each individual data point as a continuous embedding parameter and decrease the weight gradually from one to zero to link the estimators based on the full data and those with a case deleted. We show that the case-weight adjusted solution path is piecewise linear in the weight parameter. This allows us to compute all LOO estimators efficiently. Moreover, we can use the solution path to generate case influence graphs and perform LOO cross validation for model selection. Case influence measures for classification methods are understudied in the literature. We propose a variety of overall case influence measures for large margin classifiers and empirically find that using some loss functions are quite effective in assessing case influence. Moreover, we demonstrate using real-world datasets that the proposed method is able to detect outliers in the feature spac (open full item for complete abstract)

Committee: Yoonkyung Lee (Advisor); Yunzhang Zhu (Advisor); Steve MacEachern (Committee Member); Mario Peruggia (Committee Member) Subjects: Statistics

Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering

Legged robots often need to move through different terrains as they function. This requires a change of gaits by the robot in order to move with better efficiency. There has been a lot of research done to find out which gait works better for a given terrain so that the robot can change its gait accordingly. A reliable analysis of when exactly should the transition take place in a walking robot is important, so that there can be an assurance of stability in the locomotion of the robot during the transition between different gaits. This work presents analysis performed on a hexapod robot that can walk in three different gaits: Tripod gait, Ripple gait, and Wave gait, all on a flat terrain. The goal is to optimize the transition of the robot between these gaits by analyzing its stability during motion as the transition is initiated at different times during the stride, called the phase here. A reliable phase at which each transition can be implemented is analyzed with the help of a calculated cost of transition, which is based on the roll and pitch of the robot, and the general body stability margin, which relies upon computation of the support polygon. The roll and pitch of the robot are obtained from simulation of the walking robot as it transitions between gaits, while the stability margin during walking is computed in MATLAB. These values are then combined to determine the cost of transition as the function of the phase at transition. Ultimately, this can be used in real-time walking to determine when transitions should be initiated.

Committee: Luther R. Palmer, III Ph.D. (Advisor); Zach Fuchs Ph.D. (Committee Member); Xiaodong Zhang Ph.D. (Committee Member) Subjects: Electrical Engineering; Robotics

Doctor of Philosophy, The Ohio State University, 2016, Electrical and Computer Engineering

Large-scale power outages are rare but extreme accidents. They are usually caused by severe weather events and overloading caused cascading failures. Nowadays, with climate change and ever-increasing load demand, power blackouts are happening more frequently. In order to ensure reliable power delivery to customers, resilient distribution systems are envisaged, because of their characteristics of high reliability, power quality, advanced protection, and optimal restoration. During extreme events, they can provide uninterruptible power supply to critical loads, quickly detect and accurately isolate fault areas, and reestablish with an optimal restoration plan. This dissertation first proposes to develop community microgrids within distribution systems by integrating local distributed energy resources (DERs) and neighboring load centers, especially critical loads. Community microgrids can be useful means of providing resilient electricity service by enabling sustainable operations and supporting critical loads in the event of power disruptions. When an extreme event happens, the distribution system can be seamlessly partitioned into several energy-independent community microgrids. Then, the important customers are supplied with uninterrupted power by local DERs. After fault isolation, distribution systems are restored by reconnecting these community microgrids. The DER selection for community microgrids is mainly determined by the levelized cost of energy (LCOE) based quantitative assessment in conjunction with the quality functional deployment (QFD) tool. Subsequently, the capacity planning of dispatchable generation units, like natural gas gensets and battery energy storage system (BESS), is elaborated. The goal of this sizing scheme is to keep adequate reserve margin to ride through unforeseen events, like uncertainties from loads and renewables, loss of generation, etc. This is because when community microgrids work in the islanded mode, the critical loads co (open full item for complete abstract)

Committee: Mahesh Illindala Dr. (Advisor); Jin Wang Dr. (Committee Member); Jiankang Wang Dr. (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2015, Electrical and Computer Engineering

THz-frequency spectroscopic imaging has recently drawn increasing attention as a novel modality for bio-medical analysis of diseases and conditions of living tissues. More importantly, detection of cancerous tumors as well as necrotic tissue regions is being studied using THz waves with the aim of translating research studies into clinical practice. THz radiation provides unique sensing capabilities applicable to a variety of areas including non-destructive inspection, security screening, as well as bio-medical imaging. THz waves are safe (non-ionizing), and they can provide high-resolution with better specificity compared to X-rays. In addition, THz waves enable the spectroscopic analysis of organic molecules, since many of their rotational and vibrational resonances fall within the THz band. Perhaps more importantly, THz waves are extremely sensitive to the degree of sample hydration and this property has been utilized to differentiate cancerous tissue regions. However, previous studies on human tissue groups have been largely disconnected, with publications focusing on only limited tissue groups at a time. In addition, assessment of cancer margins to differentiate in-situ extent of disease has rarely been a major focus. As such, a more general in-depth study of the THz response of extended human tissue groups is much desired to demonstrate the potential of THz sensing as a clinical tool. In this work, we initially focus on a comprehensive experimental study of the THz response of major human tissue malignancies to investigate the efficacy of THz sensing as a clinical bio-medical tool. In particular, using the THz-band spectroscopic reflectivity and transmission properties of bulk and thin tissue samples, we characterize optical properties associated with the corresponding tissue characteristics. To do so, we develop calibration techniques to take into account experimental fixture effects. In addition, the specificity and sensitivity of the commercial time-doma (open full item for complete abstract)

Committee: Kubilay Sertel (Advisor); Fernando Teixeira (Committee Member); Umit Catalyurek (Committee Member); Niru Nahar (Committee Member) Subjects: Biomedical Engineering; Electrical Engineering

MS, University of Cincinnati, 2014, Engineering and Applied Science: Mechanical Engineering

The main objective of this thesis work was to investigate different image classification and pattern recognition methods to try to develop a validation metric. A validation metric is a means of comparison between two sets of numerical information. The numerical information could represent a set of measurements made on a system or its internal characteristics derived from such measurements. A validation metric (v-metric) is used to determine the correctness with which one of the data-sets is able to describe the other and to quantify the extent of this correctness. A moment descriptor method has been identified from among the most widely used image classification and pattern recognition methods as the system most likely to give way to an effective validation metric for reasons discussed in subsequent chapters. Different sets of Orthogonal Polynomials have been investigated as kernel functions for the aforementioned method to generate descriptors that depict the most significant features of the data-sets being compared. The algorithms developed as such have been verified using standard gray-scale and color images to establish their ability to reconstruct the image intensity function using a subset of the features extracted. The above Orthogonal Polynomials have then been used to extract features from two measured data-sets and means to develop a v-metric from these descriptors have been explored. A study of algorithms thus developed using different Orthogonal Polynomials has been made to compare their effectiveness as well as shortcomings as kernel functions for developing a v-metric. An alternate form of the existing two dimensional moments has been proposed to generate features that are more conveniently compared against each other. This method has been examined to determine its efficiency in reducing the amount of information that needs to be used in the final comparison for multiple pairs of data-sets. A way to effect such a comparison using singular (open full item for complete abstract)

Committee: Randall Allemang Ph.D. (Committee Chair); David L. Brown Ph.D. (Committee Member); Allyn Phillips Ph.D. (Committee Member) Subjects: Mechanics

PHD, Kent State University, 2014, College of Arts and Sciences / Department of Earth Sciences

Reconstructing sedimentary processes associated with the deglacial events in the Chukchi Margin is necessary to evaluate the deglacial and Holocene flow regime in the Chukchi margin area, which was the purpose of this study. To provide context for the paleoceanographic reconstruction, the modern system was explored using multispectral band ratio analysis of the marine portions of Landsat images. Terrestrial processes were investigated using visual geomorphic description and unsupervised classification to define land cover classes and sediment sources. Thermal images and band ratios clearly demonstrate that flow regimes influence sediment transport, variations of the plant pigment, sea ice content and particle density. Using 1040 samples from five sediment cores and 27 surface samples from the Chukchi Margin, sediment composition was evaluated by comparison of visible and near infrared (VNIR) derivative spectroscopy, while sediment texture was explored using laser-particle grain size analysis. Varimax-rotated principal component analysis (VPCA) on several different multivariate data sets was employed to address the multi-colinearity inherent in this type of dataset. VNIR derivative spectroscopy was used to identify mineralogical compositions of dolomite + illite; goethite + chlorophyllide-a; smectite + chlorite and calcite in the Chukchi Margin area. Strong influence of Arctic Oscillation from the mid-Holocene to present enhanced the iron minerals with a provenance from Russian seas. Enhancement of the smectite + chlorite component during 6000 to 3500 yr BP exhibits an influx of Pacific waters related to mid Holocene Warming. The enhancement of the dolomite + illite component in recent years might indicate dominant sediment provenance from east in the Victoria Island/McKenzie River basin. IIlite was identified as an appropriate water mass tracer for a reverse flow from the Arctic into the North Pacific because of its prominence and abundance in the Mackenzie Rive (open full item for complete abstract)

Committee: Joseph Ortiz PHD (Advisor); Alison Smith PHD (Committee Member); Anne Jefferson PHD (Committee Member); Thomas Schmidlin PHD (Committee Member); John Dunlosky PHD (Committee Member) Subjects: Climate Change; Geology; Marine Geology; Oceanography; Paleoclimate Science

Doctor of Philosophy, The Ohio State University, 2014, Mechanical Engineering

Cancer remains a substantial health burden in the United States. Traditional treatments for solid malignancies may include chemotherapy, radiation therapy, targeted therapies, or surgical resection. Improved surgical outcomes coincide with increased information regarding the tumor extent in the operating room. Furthermore, pathological examination and diagnosis is bettered when the pathologist has additional information about lesion locations on the large resected specimens from which they take a small sample for microscopic evaluation. Likewise, cancer metastasis is a leading cause of cancer death. Fully understanding why a particular tumor becomes metastatic as well as the mechanisms of cell migration are critical to both preventing metastasis and treating it. This dissertation utilizes the complex interactions of induced electric fields with tissues and cells to meet two complementary research goals. First, eddy currents are induced in tissues using a coaxial eddy current probe (8mm diameter) in order to distinguish tumor tissue from surrounding normal tissue to address the needs of surgeons performing curative cancer resections. Measurements on animal tissue phantoms characterize the eddy current measurement finding that the effective probing area corresponds to about twice the diameter of the probe and that the specimen temperature must be constant for reliable measurements. Measurements on ten fresh tissue specimens from human patients undergoing surgical resection for liver metastases from colorectal cancer showed that the eddy current measurement technique can be used to differentiate tumors from surrounding liver tissue in a non-destructive, non-invasive manner. Furthermore, the differentiation between the tumor and normal tissues required no use of contrast agents. Statistically significant differences between eddy current measurements in three tissue categories, tumor, normal, and interface, were found across patients using a Tukey's pairwis (open full item for complete abstract)

Committee: Vish Subramaniam (Advisor); Shaurya Prakash (Advisor); Carlos Castro (Committee Member); Charles Hitchcock (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Electromagnetics; Engineering; Experiments; Mechanical Engineering; Medical Imaging

Master of Science (MS), Wright State University, 2013, Earth and Environmental Sciences

Trace metals in the ocean are derived from natural and anthropogenic sources. Despite increased human impact on the marine environment and biological productivity of continental margins, trace metal studies in marine sediments have focused primarily on near-shore regions. I investigated 22 metals in sediments on the continental margin of the northwest Atlantic Ocean to calculate enrichment factors (EF) relative to upper continental crust and identify spatial variations with distance from shore and depth below the sediment-seawater interface. Metals were well correlated with Al, Fe, organic matter, or CaCO3. No clear trends in metal EFs with distance from shore were evident on a station by station basis, but consistent differences among regions of the continental margin were evident. Significant near-shore enrichment was observed. Enrichment was also evident for As, Hg, Mn, and Ni in sediments farther off-shore, suggesting the influence of human activities or hydrothermal vent emissions have enriched deep ocean sediments.

Committee: Chad Hammerschmidt Ph.D. (Advisor); Chad Hammerschmidt Ph.D. (Committee Chair); Carl Lamborg Ph.D. (Committee Member); William Fitzgerald Ph.D. (Committee Member) Subjects: Chemical Oceanography; Environmental Science; Oceanography

Master of Science in Electrical Engineering, Cleveland State University, 2013, Fenn College of Engineering

In this thesis, the impact of the disturbance rejecter concept and the enforced plant has been explored. In order for the active disturbance rejection controller (ADRC) to provide a reasonable alternative to the industry standard PID controller, it is necessary to develop tuning procedures capable of providing adequate performance with reasonable stability margins. A focus should be placed upon the disturbance rejecter, as it is the heart and soul of ADRC. In this thesis, transfer function analysis of the enforced plant has been performed to connect ADRC with the tools from classical control. The relationship between the gain parameter and observer bandwidth are studied to understand why higher bandwidths are attainable with smaller gains. A root locus technique demonstrates how the plant roots change with observer bandwidth. The Nyquist stability criterion is used to offer tuning methods that satisfy gain and phase margins and ensures a transient that satisfies a given damping requirement. A technique is offered to display the infinite radius encirclements of the Nyquist plot within a finite graph. Analysis is performed on why the controlled response is typically slower than desired and how to correct it.

Committee: Zhiqiang Gao PhD (Committee Chair); Lili Dong PhD (Committee Member); F. Eugenio Villaseca PhD (Committee Member) Subjects: Electrical Engineering; Engineering

Doctor of Philosophy, The Ohio State University, 2013, Agricultural, Environmental and Developmental Economics

Milk markets are considered inherently unstable for several reasons: perishability of the raw product, continuous production, and seasonal changes in supply and demand. As a result a variety of government programs work to address potential market failures in milk production and pricing. Among the policy initiatives are Federal Milk Marketing Orders (FMMOS) and commodity specific price support programs. FMMOS employ a classified pricing system based on the end use of milk and a revenue blending program to announce and enforce minimum farm payments. Price supports and counter-cyclical payment program provides milk price support when milk prices of specific commodities fall below specified thresholds. Designed for an environment with stable milk and feed prices these programs are now viewed to be inadequate as they fail to address the industry need to manage price volatility. Private market solutions do exist, such as commercially traded futures contracts, but contract design specifications and capital commitments (margin accounts) make these risk management alternatives less than ideal. Policy solutions in the dairy industry include addressing and potentially limiting the role of FMMOS in milk pricing, and providing subsidized risk management tools. The potential for significant changes in the marketing and pricing of milk exists and it is useful to consider policy options for managing risk in a modern dairy economy. In order to contribute to this discussion the dissertation is comprised of three research manuscripts addressing the role of the government in facilitating or designing cost-effective risk management platforms.

Committee: Camerson Thraen S (Advisor); Stan Thompson (Committee Member); Brent Sohngen (Committee Member) Subjects: Agricultural Economics

MARCH, University of Cincinnati, 2010, Design, Architecture, Art and Planning : Architecture (Master of)

Cities in North America are undergoing an organizational shift as urbanization increasingly expands outward, horizontally and diffusely. Left in the wake of decentralization and urban restructuring are sites of waste. When viewed by a culture obsessed with clean and orderly space these sites are reified as valueless entities and classified as waste landscapes. They are exiled to precincts beyond public perception. The conventional approaches to waste landscapes in urban design appear ill suited to address these emergent challenges. All too often designers prioritize centralized and technocratic methodologies that continue to reinforce dualistic processes. The designs place culture in opposition to nature, construction in opposition to landscape, and everyday space in opposition to waste landscapes. This thesis implements a multivalent approach within the domain of landscape. Landscape is no longer subjugated as supporting cultural operations. It is reframed as a constructed ground written by culture. Landscape becomes an author of an unfolding and interwoven process binding ecology and society. The thesis investigates the conditions surrounding Cincinnati's Mill Creek and how an integrative approach can reintroduce a public realm into waste landscapes and create awareness and incremental change. The integrative approach is explored at fifteen public sites along the Mill Creek that pass through the proposed Mill Creek Greenway. The parametric design strategy addresses issues of watershed health and management by introducing interventions that prioritize ecological and cultural processes over static form-based design. To foster interventions flexible to local conditions and the inevitability of change the design deploys a batch of programmatic ingredients called the kit of program, a kit of parts to unify the architectural language of the sites, an organizational framework for future interventions, and a representational focus that seeks to decouple the picturesqu (open full item for complete abstract)

Committee: Aarati Kanekar PhD (Committee Chair); Rebecca Williamson PhD (Committee Chair) Subjects: Architecture

MARCH, University of Cincinnati, 2005, Design, Architecture, Art and Planning : Architecture (Master of)

This thesis draws on the work of Edward Soja and his Thirdspace theory to apply a hypothesis and a methodological approach to urban design. An understanding of paradoxical space and political margins are filtered through the Thirdspace model to develop an idea about heterogeneous connections of urban networks. The research discusses the politics and perception of space and the power structures that maintain unhealthy urban relationships. The main focus of this thesis is to diagram and abstract social relationships as they are understood through post-structuralist and feminist critiques and then apply this hypothesis to a physical design project on Third Street in downtown Cincinnati/riverfront that further abstracts these relationships into a theory of urban connectivity. The subject for this thesis is the connection of intra-urban identities and mobility; how people move through space and across these different urban places (particularly pedestrians) and the locations of interest are those left-over conditions that bind urban spaces and often make them impassable such as underpasses and highways. The social theories of heterogeneous connections are grafted onto deficiencies in the urban environment through the design of urban programming and infrastructure to become larger connective tissues in the metaphorical environment by suturing together disconnections in the physical environment.

Committee: Michael McInturf (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2012, Nuclear Engineering

Utilities operating nuclear power plants in the United States are required to demonstrate that their plants comply with the safety requirements set by the U.S. Nuclear Regulatory Commission (NRC). How to show adherence to these limits through the use of computer code surrogates is not always straightforward, and different techniques have been proposed and approved by the regulator. The issue of compliance with regulatory limits is examined by rephrasing the problem in terms of hypothesis testing. By using this more rigorous framework, guidance is proposed to choose techniques to increase the probability of arriving at the correct conclusion of the analysis. The findings of this study show that the most straightforward way to achieve this goal is to reduce the variance of the output result of the computer code experiments. By analyzing different variance reduction techniques, and different methods of satisfying the NRC's requirements, recommendations can be made about the best-practices, that would result in a more accurate and precise result. This study began with an investigation into the point estimate of the 0.95-quantile using traditional sampling methods, and new orthogonal designs. From there, new work on how to establish confidence intervals for the outputs of experiments designed using variance reduction techniques was compared to current, regulator-approved methods. Lastly, a more direct interpretation of the regulator's probability requirement was used, and confidence intervals were established for the probability of exceeding a safety limit. From there, efforts were made at combining methods, in order to take advantage of positive aspects of different techniques. The results of this analysis show that these variance reduction techniques can provide a more accurate and precise result compared to current methods. This means an increased probability of arriving at the correct conclusion, and a more accurate characterization of the risk associated with even (open full item for complete abstract)

Committee: Tunc Aldemir PhD (Advisor); Richard Denning PhD (Committee Member); Marvin Nakayama PhD (Committee Member); Alper Yilmaz PhD (Committee Member) Subjects: Nuclear Engineering; Statistics

Doctor of Philosophy, The Ohio State University, 2010, Industrial and Systems Engineering

The emergency medicine system absorbs much of the burden of the chronic problems facing healthcare in the United States today: an increasingly unhealthy populace, variability in access to primary care, and severe resource shortages. This makes emergency medicine, and in particular the emergency department (ED), an excellent natural laboratory in which to study adaptation and cognitive work. The primary objectives of this research are to 1) identify how differing availability of resources influences timeliness of admission for lower-resourced and higher-resourced patient cohorts, and 2) identify strategies for managing margin of maneuver in a complex, socio-technical setting. This research was conducted from a cognitive systems engineering perspective, which has adaptation to complexity as a central conceptual lens. The research was conducted in an ED at one academic hospital; this environment is a complex, socio-technical setting, being characterized by high uncertainty, high consequences for failure, distributed work across specialized roles, and high variation in workload. In particular, this dissertation examines one problem, patient boarding, focusing on the causes and correlates of boarding for two contrasting patient cohorts. A cognitive systems engineering perspective focuses analysis on how boarding exacerbates, and is exacerbated by, challenges to workload capacity, coordination, and ultimately resilience in the ED. Both observations of actual ED work and aggregate chart review are used as inputs to the analysis. The findings have implications for short- and long-term interventions to address boarding and other quality of care-related issues in the ED. Selected findings include that the barriers and facilitators to patient admission are different for patient cohorts that have comparatively more and less resources, and that a variety of solutions, including the creation of a special buffer, are used by the ED to ease the impact of lower-resourced patient coh (open full item for complete abstract)

Committee: Emily Patterson PhD (Advisor); David Woods PhD (Committee Member); Philip Smith PhD (Committee Member) Subjects: Industrial Engineering

Master of Science, The Ohio State University, 2009, Industrial and Systems Engineering

The operation of a pumped storage hydroelectric facility is subject to uncertainty. This is especially true in today's energy markets. Published models to achieve optimal operation incorporate mechanical details of generating and pumping units, but are deterministic. The purpose of this study is to establish a model that considers uncertainty in the market price of electricity and the water inflow rate from river streams to the reservoirs. Due to the nature of the stochastic problems, a dynamic programming approach is taken. The model balances the amount of water used in the current stage and the amount of water saved for the future stages in order to maximize the total gross margin. The meta-models are constructed to evaluate the amount of water used and pumped in the current stage, and the gross margin for different schedules. The uncertainty in the market price of electricity is handled by solving for different price scenarios and estimating the meta-model error. The amount of available water for the future stages is not perfectly predictable either, as the water inflow rate to the reservoirs is subject to uncertainty. For our model, the transition in water inflow rate is simulated by a Markov process. The resulting schedule turned out to be more conservative compared to the deterministic counterpart.

Committee: Clark A. Mount-Campbell PhD (Advisor); Brevick Jerald PhD (Committee Chair) Subjects: Operations Research