Search results

Title: Thermal Effects in Fluid Dynamics
Creator: Sulzbach, Jan-Eric
Date: 2021
Description: In this thesis we propose a mathematical framework modeling non-isothermal fluids.The framework is based on a coupling between non-equilibrium...
Show moreIn this thesis we propose a mathematical framework modeling non-isothermal fluids.The framework is based on a coupling between non-equilibrium thermodynamics and an energetic variational approach for the mechanical parts of the system. From this general model we derive and analyze three separate systems.The first application is the Brinkman-Fourier model. This is related to the ideal gas system, where the pressure and internal energy depend linearly on the product of density and temperature. This is a subsystem to the general Navier-Stokes-Fourier system. We prove the existence of local-in-time weak solutions via compensated compactness arguments.The next model we study is a non-isothermal diffusion system involving chemical reactions. For a system close to chemical equilibrium we show the well-posedness of classical solution using a fixed-point argument involving theory of homogeneous Besov spaces.The third application of the general theory is for another general diffusion system with a Cahn-Hilliard energy. In this framework, we study in detail how the temperature can affect the system on different scales, leading to different models. For the analysis, we focus on one case and show the well-posedness of classical solutions. The proof relies on methods from the theory of Besov spaces and paradifferential calculus.
Show less

Title: Technological Consciousness in Midwestern American Farming: From Party Lines to Autonomous Tractors
Creator: Sziron, Mónika
Date: 2022
Description: This dissertation is primarily concerned with understanding the current conceptions, perceptions, and ethical concerns of artificial...
Show moreThis dissertation is primarily concerned with understanding the current conceptions, perceptions, and ethical concerns of artificial intelligence in Midwestern agriculture. Using the theory of technological consciousness as a backdrop for understanding the relationship between Midwestern agriculture and technology, in chapter two this dissertation first provides a narrative review of major technological developments throughout history in Midwestern farming and how the human experience in farming is influenced by technology throughout history. This history provides context for the current state of Midwestern agriculture, which is now increasingly entangled with artificial intelligence. The theory behind artificial intelligence ethics and general trends in artificial intelligence are discussed in chapter three. To understand present conceptions, perceptions, and ethical concerns of artificial intelligence for Midwestern farmers, a pilot survey was dispersed to farmers and pilot media content analysis was conducted on Midwestern agriculture publications. The results from this pilot survey and pilot media content analysis are discussed in chapter four. Chapter five delves into theory and how the human experience with technology has evolved over time and its effects on the human experience today. This chapter also provides theoretical insights for the future of farming with artificial intelligence. The dissertation concludes with reviewing the ethical concerns relating to artificial intelligence in agriculture for Midwestern farmers, provides recommendations for developers of agriculture technology, and highlights the new partnership between farmers and computer scientists and how this partnership will lead the way in the future of Midwestern farming.
Show less

Title: DO ACT CONSTRUCTS MODERATE ASSOCIATIONS BETWEEN SOCIAL MEDIA AND EATING PATHOLOGY?
Creator: Badillo Regan , Krystal E
Date: 2022
Description: Limited research has assessed individuals with disordered eating and their social media use. Additionally, there has been limited...
Show moreLimited research has assessed individuals with disordered eating and their social media use. Additionally, there has been limited investigation into psychotherapy constructs that could be used when addressing social media use in those with eating pathology. This study aims to improve the existing literature on social media and eating pathology by recruiting a sample of probable eating disorders and assessing if Acceptance and Commitment Therapy (ACT) constructs moderate the relation between social media and eating pathology. It is anticipated that 1) eating disorder pathology severity will be positively correlated with photo-based social media behavior; 2) eating disorder symptom severity will be positively associated with importance of social media; and 3) those who score higher in mindful eating, body image flexibility, and body image acceptance will have a weaker positive association between ED pathology and importance of social media and those who score lower in body image cognitive fusion will have a weaker positive association between ED pathology and importance of social media mindful eating, body image flexibility, body image acceptance, and body image cognitive fusion will moderate the relation between eating disorder symptom severity and social media use. To test the hypotheses women with a probable eating disorder (N=121) completed online questionnaires via prolific. The majority of participants identified as non-Hispanic (81%) and White (45.5%). Results suggest that there are associations between ED pathology, ACT constructs, Importance of Twitter and Instagram, and photo-based behaviors but not Importance of Facebook. Additionally, the moderation models examined were not statistically significant. Implications of these findings are discussed as well as future direction for research and clinical work.
Show less

Title: OPTIMUM WEIGHT STIFFNESS STRUCTURAL DESIGN
Creator: Barnett, Ralph L.
Date: 2021
Description: My adventures with flexible structures began on the IIT campus with an extracurricular undergraduate project to design an “Open House Exhibit”...
Show moreMy adventures with flexible structures began on the IIT campus with an extracurricular undergraduate project to design an “Open House Exhibit” for the Civil Engineering Department. I chose to display a reinforced concrete diving board together with a prestressed concrete diving board. Visitors enthusiastically pounced on the reinforced concrete structure whose rigid response disappointed one and all. Their indignation was transferred to the prestressed cantilever which thrust them upward from six to ten feet into the air. This unexpected response from a diving board became so dangerous that the Exhibit was unceremoniously closed. I still have the display sign, “More Bounce to the Ounce.”While still an undergraduate, I secured a part-time job at Armour Research Foundation where I responded to a bid request from Rock Island Arsenal to design the 26 foot Honest John Rocket Launcher Rail at minimum weight. This tactical weapon was transported by helicopter. I basked in the fantasy that I was Leonardo da Vinci without his artistic proclivity. Rocket launchers that droop during operation are similar in concept to a circular firing squad. So began my research into minimum weight beams based on deflection rather than strength. I searched for the shoulders of Giants. I found them in the form of mathematicians not structural engineers. I achieved a 26.5% weight savings in the 1126 pound rail by optimizing the geometry. When I developed an optimum prestressed and segmented Kentanium cermet rail, the weight savings became 89%. The right material provides a bigger bang for the buck. When my journey into optimum design began, I was armed only with analysis tools: strength, stability, and stiffness. This thesis begins with an outline of my present toolbox which contains eight design concepts: 1. Establish the Geometry, 2. Select a material from a finite number of candidates, 3. Prestress and Prestrain, 4. Statistical Screening (Proof Testing), 5. Manipulation of Boundary Conditions, 6. Energized Systems, 7. Counterweights, 8. Self-Healing and Self-Reinforcing. Four of these are used through this review which focuses on stiffness. Beginning with beams, deflection control examples are described where prestraining and prestressing techniques are used to produce both a zero-deflection beam and a method for pushing with a chain. The calculus of variations made it possible to establish optimum tapers for the flanges and webs of I-beams that minimize beam weight for a specified deflection or, because of reciprocity, minimize beam deflection for a specified beam weight. An anomaly is encountered that enables one to achieve an upward, downward, or zero deflection with a set of beams of vanishing weight. In addition, special circumstances are defined where a uniform strength design is identical to the minimum weight design based on a specific deflection. Closed form solutions are obtained for a variety of loading scenarios. One problem is presented for self-weight that leads to a nonlinear integral equation. The optimum stiffness-weight design of trusses is undertaken where the area distribution of the truss members is optimized using Lagrange’s method of undetermined multipliers. Once again, we obtain a degenerate case where upward, downward, and zero deflection conditions can be met with an infinite set of trusses of vanishing weight. We photograph a simply supported truss under a downward load that leads to an upward deflection at one of the joints. Special loading conditions are identified that lead to uniform stress designs that are identical to the minimum weight designs based on deflections. This study provides a Segway into the world of minimum weight strength design of trusses. The resulting Maxwell and Michell trusses sometimes display the optimum distribution of bar areas from the point of view of stiffness. Many practitioners are under the mistaken impression that Michell structures, when they exist, provide the optimum truss profile for stiffness. Unfortunately, the optimum array of truss joints based on deflection does not exist. For both trusses and beams the optimum distribution of mass is shown to be necessary and sufficient; the sufficiency is established using well-known inequalities. The role of stiffness in the design of columns is explored in our final chapter. This cringe-worthy history of column analysis begins our study as a warning to practitioners who use analysis as their basis for design and especially optimum design. Conventional elastic and inelastic buckling theories provide little insight into the design of columns. The fundamentals of minimum weight column design are presented to show the power of design theory in contrast to analysis. Both prismatic and tapered columns are studied with one surprise result; the optimum taper gives rise to a uniform bending stress (without axial stresses). It was fun to see that in 1733 Lagrange made a mistake in calculus of variations that led to the incorrect solution for the optimum tapered column. It took 78 years before Clausen obtained the correct solution. The problem has been revisited by William Prager and again by the author who used dynamic programming. Of course, we all got the same result which is a dreadful solid circular tapered column that is heavier than any ordinary waterpipe. The best of a class is not necessarily the best possible design. Under the heading, “Intuition is a good servant but a bad master,” we introduce the notions of tension members that buckle, columns constructed from spherical beads, optimum rigging of crane booms, and deflection reversal of beam-columns. In several places we observe that the weight of optimum columns is proportional to P^α where P is the axial load and α is less than unity. We fail to tell the reader that this implies that minimum weight columns require putting all your eggs in one basket; one column under load P is lighter than two columns each under load P/2. On the other hand, we expose the solid circular column as the least efficient shape among all regular polygons, the equilateral triangle is the best. Indeed, there is a family of rectangles that are superior to the circular cross-section. Finally, the author’s prestressed tubular column is introduced that is pressurized to eliminate local buckling. Euler’s buckling can always be eliminated with a thin-wall section of sufficient width without a weight penalty. The weight of the balloon-like member is proportional to (PL) which implies that at last we have a compressive member that meets the requirement of a Michell structure. Bundling of pressurized gas columns are possible without a weight penalty. Further, the column is insensitive to most imperfections. It is the lightest known column for small structural indices (P/L^2 ). When coupled with circulating cryogenic liquid as a prestressing system, a limiting column has a vanishing weight.
Show less

Title: A Network Analysis of the Six Core Processes Associated with Acceptance and Commitment Therapy
Creator: Bailey, Jennifer Rose
Date: 2022
Description: According to the theoretical model of Acceptance and Commitment Therapy, six core processes comprise a latent factor of psychological...
Show moreAccording to the theoretical model of Acceptance and Commitment Therapy, six core processes comprise a latent factor of psychological flexibility: present moment, chosen values, committed action, self as context, cognitive defusion, and acceptance. Little research has directly examined the unique relations among the processes. The present study extended our knowledge of the structure and relations between these processes by examining the relative importance and influence of a single process to the system of processes as a whole utilizing network analysis with a sample of 277 adult, non-clinical participants. Committed action was the most central of all the processes, demonstrating the highest strength centrality and most number of edges. Cognitive defusion and present moment also showed high strength centrality, suggesting that these processes exert the greatest influence on other processes in the network based on partial correlations controlling for all other constructs. Results provided support for the conceptualization of the three response styles (i.e., open, centered, and engaged). The addition of neuroticism to the core processes network showed little effect on the number of edges present between the six core processes. Neuroticism was strongly related to cognitive defusion and more weakly related to committed action. Results not only increased our understanding of the relations between processes and provided knowledge that may be useful to our understanding of the ACT theoretical model, but it also may have potential clinical implications, such as aiding in the identification of treatment targets to enhance psychological flexibility.
Show less

Title: Sharpen Quality Investing: A PLS-based Approach
Creator: Jiao, Zixuan
Date: 2022
Description: I apply a disciplined dimension reduction technique called Partial Least Square (PLS) to construct a new quality factor by aggregating...
Show moreI apply a disciplined dimension reduction technique called Partial Least Square (PLS) to construct a new quality factor by aggregating information from 16 individual signals. It earns significant risk-adjusted returns and outperforms quality factors constructed by alternative techniques, namely, PCA, Fama-Macbeth regression, a combination of PCA and Fama-Mabeth regression and a Rank-based approach. I show that my quality factor performs even better during rough economic patches and thus appears to hedge periods of market distress. I further show adding our quality factor to an opportunity set consisting of the other classical factors increases the maximum Sharpe ratio.
Show less

Title: MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DISCONTINUOUSLY PRECIPITATED NI-CO-AL ALLOYS
Creator: Ho, Kathy
Date: 2022
Description: The study of high temperature structural materials has been one of great interest and immense focus in recent years of research and...
Show moreThe study of high temperature structural materials has been one of great interest and immense focus in recent years of research and development. With the capability of catering to specific needs and applications while being commercially cost-effective, these materials can be synthesized using various types of methods and materials for a large range of applications. In order to implement the advantageous properties of these materials for practical use in service, empirical data relating to the material and mechanical properties of these high temperature structural alloys must first be obtained. This can be achieved through numerous processing methods. One particular method involves precipitation strengthening. Two types of transformation modes include discontinuous and continuous precipitation. Discontinuous precipitation (DP) nucleates at high angle, incoherent grain boundary, grows through grain boundary diffusion, and produces a lamellar structure consisting of alternating layers of γ and γˡ (Ephler, 2004). Continuous precipitation (CP) nucleates within the grain, is controlled through volume diffusion producing, and results in a homogeneous distribution of equilibrium composition precipitates with a spherical/cuboidal morphology. Since both modes of transformation possess a chemical driving force, resulting from the supersaturation of solute, the coexistence of both DP and CP transformation in a material is possible. However, as demonstrated from past studies, the presence of a partial DP transformation in structural alloys is undesirable as detrimental effects on mechanical properties are observed. As a result, numerous studies have focused on suppressing DP all together. In 1972 Erhard Hornbogen hypothesized that a fully DP transformed material would yield superior mechanical properties, similar to pearlite formation in steel, since the lamellar structure would increase barriers to dislocation movement (Hornbogen, 1972). As a result, recent studies have redirected their focus in an effort to encourage DP transformation to completion for improved mechanical properties. Therefore, the purpose of this work was to 1) determine the aging conditions under which a complete, 100% DP transformation would be achieved in select alloys, 2) determine the conditions where optimal precipitate size via CP transformation is obtained to effectively use precipitation strengthening without the concern of over-aging, 3) experimentally compare the material and mechanical properties between 100% DP aged samples and CP aged samples consisting of the optimal precipitate size, 4) compare the mechanical properties between alloys that have undergone a complete DP transformation to commercial alloys currently used in service, and 5) provide empirical data to verify Hornbogen’s claim. The results from this work indicated that 1) a lower aging temperature promote DP transformation while a higher temperature promotes CP transformation, 2) a smaller grain size prior to aging was more favorable for DP transformation while larger grains were favorable for CP transformation, 3) a complete DP transformation was observed for Alloy 9 and Alloy 10 after aging at 500°C for 4 hours and 550°C for 4 hours, 4) Alloy 1, Alloy 3, and Alloy 5 were potentially undergoing a different type of transformation at lower DP aging temperatures, where β phase was present, 5) optimal precipitate size for effective use of precipitation strengthening (CP transformation) was achieved under CP aging conditions 700°C-1HR for Alloy 10 and 750°C-1HR for Alloy 9 and the forged stock bar, 6) a small fraction of DP consistently formed at the grain boundaries of the CP aged samples for all alloy samples, indicating that the nucleation of DP was quick, but growth was limited, 7) mechanical properties of the DP aged samples for Alloy 9, Alloy 10 and the forged bar were superior to their corresponding CP aged samples in terms of the hardness, UTS, and yield stress, but were less ductile than the CP aged samples, and 8) the mechanical properties of DP aged samples for Alloy 9, Alloy 10, and the forged bar were comparable, and at times superior, to the commercially available alloys. Due to limited prior research conducted on the mechanical properties of DP alloys, this investigation serves as a pioneering effort experimentally determine if the mechanical properties of completely DP transformed material are superior to that of CP transformed material, aged to optimal precipitate size, while collecting empirical data to verify Hornbogen’s claim.
Show less

Title: EMAT DESIGN CONFIGURATIONS AND SOFTWARE-DEFINED ULTRASONIC COMMUNICATIONS THROUGH METALLIC CHANNELS IN NUCLEAR FACILITIES
Creator: Huang, Xin
Date: 2022
Description: Nuclear facilities are partitioned into different blocks, and all equipment therein is well-packed for isolation purposes. The primary...
Show moreNuclear facilities are partitioned into different blocks, and all equipment therein is well-packed for isolation purposes. The primary barriers of each block include a thick, reinforced, high-strength concrete wall. The presence of physical boundaries introduces a major challenge to implementing wired or radio frequency (RF) wireless communication. Achieving data communication through the solids channel, especially considering the complex environment in nuclear power plants, is very challenging. Ultrasonic communication is a desirable method for information transfer through solid mediums such as metallic bars or pipes. This thesis is methodologically innovative in the way it seeks the best solution for ultrasonic communications through metallic channels. Therefore, we address the following research areas: 1. The advantages of using electrical-magnetic acoustic transducers (EMATs) as transmitter and receiver; 2. The fundamentals of the EMAT structure and wave generation mechanism for ultrasonic communications; 3. The channel model and behavior of ultrasonic wave propagation in a different structure of solid channels; 4. How to minimize the adverse impact of wave dispersion and reverberation; 5. How to increase the bitrate and decrease the bit error rate (BER) of an ultrasonic communication system; 6. How to utilize the software-defined system-on-chip (SoC) platform for ultrasonic communications; and 7. How to implement secure ultrasonic video transmission through solid channels. In this thesis, we have investigated the feasibility of using Periodic-permanent-magnet electromagnetic acoustic transducers (PPM-EMATs) transmitter and receiver as the information-bearing of ultrasonic waves across the plate channels (shear horizontal waves) and pipe channels (torsional waves). Methods such as time-reversal (TR), pulse shaping, and adaptive equalizer techniques are studied for improving the signal-to-noise ratio (SNR) of ultrasonic communication systems. We also investigated a novel software-defined ultrasonic communication system (SDUC) for real-time video transmission through a highly reverberant and dispersive metallic bar channel. Furthermore, we investigated the feasibility of combining orthogonal frequency-division multiplexing (OFDM) with quadrature amplitude modulations (QAM) for bitrate peak performance. Strategies and guidelines were established for the best solutions to combat intersymbol interference (ISI) caused by the severe reverberation inherent in metallic channels. A practical solution for video transmission, adhering to the Digital Video Broadcasting Terrestrial (DVB-T) standard, was also examined for video streaming transmission of 240p, 480p, and 720p resolutions at 20 frames per second (FPS) across a rectangular aluminum bar (ARB) channel. Through ultrasonic experimental studies for channel analysis, we achieved a peak video transmission rate of 1074 kbps with 3.3×10-4 BER despite reverberation, the multipath effect, and signal fading within the ARB channel.
Show less

Title: Numerical Analysis and Deep Learning Solver of the Non-local Fokker-Planck Equations
Creator: Jiang, Senbao
Date: 2022
Description: This thesis is divided into three mutually connected parts. ...
Show moreThis thesis is divided into three mutually connected parts. In the first part, we introduce and analyze arbitrarily high-order quadrature rules for evaluating the two-dimensional singular integrals of the forms \begin{align*} I_{i,j} = \int_{\mathbb{R}^2}\phi(x)\frac{x_ix_j}{|x|^{2+\alpha}} \d x, \quad 0< \alpha < 2 \end{align*} where $i,j\in\{1,2\}$ and $\phi\in C_c^N$ for $N\geq 2$. This type of singular integrals and its quadrature rule appear in the numerical discretization of fractional Laplacian in non-local Fokker-Planck Equations in 2D. The quadrature rules are trapezoidal rules equipped with correction weights for points around singularity. We prove the order of convergence is $2p+4-\alpha$, where $p\in\mathbb{N}_{0}$ is associated with total number of correction weights. We present numerical experiments to validate the order of convergence of the proposed modified quadrature rules. In the second part, we propose and analyze a general arbitrarily high-order modified trapezoidal rule for a class of weakly singular integrals of the forms $I = \int_{\R^n}\phi(x)s(x)\d x$ in $n$ dimensions, where $\phi$ and $s$ is the regular and singular part respectively. The admissible class requires $s$ satisfies three hypotheses and is large enough to contain singular kernel of the form $P(x)/|x|^r,\ r > 0$ where $P(x)$ is any monomial with degree strictly less than $r$. The modified trapezoidal rule is the singularity-punctured trapezoidal rule plus correction terms involving the correction weights for grid points around singularity. Correction weights are determined by enforcing the quadrature rule to exactly evaluate some monomials and solving corresponding linear systems. A long-standing difficulty of these types of methods is establishing the non-singularity of the linear system, despite strong numerical evidence. By using an algebraic-combinatorial argument, we show the non-singularity always holds and prove the general order of convergence of the modified quadrature rule. We present numerical experiments to validate the order of convergence. In the final part, we propose \emph{trapz-PiNN}, a physics-informed neural network incorporated with a modified trapezoidal rule and solve the space-fractional Fokker-Planck equations in 2D and 3D. We verify the modified trapezoidal rule has the second-order accuracy for evaluating the fractional laplacian. We demonstrate trapz-PiNNs have high expressive power through predicting solutions with low $\mathcal{L}^2$ relative error on a variety of numerical examples. We also use local metrics such as point-wise absolute and relative errors to analyze where could be further improved. We present an effective method for improving performance of trapz-PiNN on local metrics, provided that physical observations of high-fidelity simulation of the true solution are available. Besides the usual advantages of the deep learning solvers such as adaptivity and mesh-independence, the trapz-PiNN is able to solve PDEs with fractional laplacian with arbitrary $\alpha\in (0,2)$ and specializes on rectangular domains. It also has potential to be generalized into higher dimensions.
Show less

Title: FACTORS INFLUENCING INDIVIDUALS’ PROVISION OF AUTONOMY SUPPORT TO THEIR PARTNERS WITH CHRONIC PAIN: A PATH ANALYSIS MODEL BASED ON SELF-DETERMINATION THEORY
Creator: Ivins-Lukse, Melissa N.
Date: 2021
Description: Receiving autonomy support from a relationship partner has been associated with increased physical activity among individuals with chronic...
Show moreReceiving autonomy support from a relationship partner has been associated with increased physical activity among individuals with chronic pain (ICP), but no studies have explored what factors may influence partners’ use of an autonomy supportive interpersonal style with an ICP. Self-determination theory (SDT) posits that contextual, perceptual, and individual factors influence how much individuals use an autonomy supportive interpersonal style through the mediators of basic psychological need satisfaction and autonomous motivation. The present study used path analysis to test a SDT model of the relationships between a contextual factor (autonomy support from health care provider), a perceptual factor (partner’s perception of ICP motivation for physical activity), an individual factor (partner catastrophizing about ICP’s pain), and the sequential mediators of relationship need satisfaction and autonomous motivation with respect to the dependent variable of partners’ use of an autonomy supportive interpersonal style. 176 partners of ICPs completed a cross-sectional survey including the Health Care Climate Questionnaire, partner-report revised Behavioral Regulation in Exercise Questionnaire, Pain Catastrophizing Scale – Significant Other version, Need Satisfaction Scale, Motivation to Help, and Interpersonal Behaviours Questionnaire-Self. The proposed model demonstrated poor fit to the data: χ2 (10) = 31.949, p < 0.001), RMSEA = 0.11 (90% CI = .07 to .16, p = 0.01), CFI = 0.81, and SRMR = .10. While the overall model was not supported, most individual pathways in the model were significant. Alternative analyses were conducted to identify a model with acceptable fit.
Show less

Title: Advances in Distribution System State Estimation
Creator: Huang, Jianqiao
Date: 2022
Description: With the increasing penetration of renewable energy in the distribution system, the system states are becoming more volatile. How to maintain...
Show moreWith the increasing penetration of renewable energy in the distribution system, the system states are becoming more volatile. How to maintain the normal operation is an urgent question to the operators. Distribution system state estimation (DSSE) is the key to the monitor and control of distribution systems.Distribution systems feature a larger number of nodes and heterogeneous measurements. Due to these features, directly employing traditional state estimation methods cannot provide fast and accurate estimation results. The existing semidefinite programming based methods show promising for the accuracy, but it is not scalable for a large system. In this thesis, we propose fast and accurate DSSE methods. First, we improve the efficiency of the state-of-art SDP-DSSE method, convex iteration (CI) method. We design a scalable convex iteration method, CDQC, by fully exploiting the radial topology of distribution system. However, the efficiency of CDQC depends on efficient feeder partition solution. It is time-consuming to get a good partition especially when the system is large. Hence, we propose a bus injection based semidefinite relaxation method (SDR-BIM) that fully exploits the radial topology of the network without the need for partitioning the networks. However, SDR-BIM has numerical issue for large scale network. This motivates us to design a branch power model based SDR-DSSE method. The proposed SDR-BPM-DSSE method improves the numerical stability and the increase in the average estimation error of voltage is less than $0.04\%$. To further improve the computational efficiency, we developed a generalized linear power flow model (GLDF) and propose an iterative method to solve the DSSE based on GLDF.Finally, the efficiency and accuracy of the proposed methods are validated on IEEE 13-bus, 37-bus, 123-bus, and 8500-node test feeders.
Show less

Title: Single Factor and Multifactor Risk Model to Measure Concentration Risk of Credit Portfolio under Basel Regulations
Creator: Ji, Junjie
Date: 2022
Description: My research discussed the essential part of Basel regulations, which is calculating the regulatory capital of bank portfolios using the...
Show moreMy research discussed the essential part of Basel regulations, which is calculating the regulatory capital of bank portfolios using the asymptotic single risk factor model (ASRF) under the internal rating-based approach (IRB). I’m trying to analyze whether the regulatory model is strong enough to measure the credit risk of banks portfolios accurately. Is the model capable of reflecting and controlling the concentration risk involved in bank portfolios? By relaxing the single factor assumption, there are models and methods to calculate unexpected loss (defined as VaR) and required capital. In my research, I propose and validate the models in different scenarios and evaluate whether they can effectively catch the tail risk of bank portfolios without overcharging required capital. My research proved that ASRF lacks the sensitivity to capture sector concentration risk. There are advantages, as well as shortcomings of each multifactor model. I propose that banks include the appropriate multifactor model in the risk management process based on their portfolios' characteristics. The result and related discussion will also contribute to addressing the conflict of banks' profitability and risk control under the Basel regulatory framework.
Show less

Title: Quantum Computation for the Understanding of Mass: Simulating Quantum Field Theories
Creator: Rivero Ramírez, Pedro
Date: 2021
Description: This thesis demonstrates the production of hadron mass on a quantum computer. Working in the Nambu–Jona-Lasinio model in 1+1 dimensions and 2...
Show moreThis thesis demonstrates the production of hadron mass on a quantum computer. Working in the Nambu–Jona-Lasinio model in 1+1 dimensions and 2 flavors, I show a separation of the contribution of quark masses and interactions to the mass. Along the way I develop a new tool called Quantum Sampling Regression (QSR) that allows for an optimal sampling of low qubit quantum computers when using hybrid variational eigenvalue solving techniques. I demonstrate the regime where QSR dominates the current standard Variational Eigensolver Technique, and benchmark it by improving the calculation of deuteron binding energy. Finally, I developed QRAND — a multiprotocol and multiplatform quantum random number generation framework — in support of the quantum computing community.
Show less

Title: SIMULTANEOUS RELEASE OF BIOACTIVE AFLIBERCEPT AND DEXAMETHASONE FROM A MICROSPHERE- AND NANOPARTICLE-HYDROGEL OCULAR DRUG DELIVERY SYSTEM FOR THE ENHANCED TREATMENT OF NON-RESPONSIVE PATIENTS WITH CHOROIDAL NEOVASCULARIZATION
Creator: Rudeen, Kayla M
Date: 2022
Description: There is a growing subset of wet age-related macular degeneration (AMD) patients who do not fully respond to standard of care treatment, which...
Show moreThere is a growing subset of wet age-related macular degeneration (AMD) patients who do not fully respond to standard of care treatment, which consists of bimonthly/monthly bolus intravitreal injections of anti-vascular endothelial growth factors (anti-VEGFs). Some of these patients may respond to a combination therapy of anti-VEGF and corticosteroids. One treatment option uses a dexamethasone implant that releases for six months. This regimen, however, requires both the bimonthly/monthly intravitreal injections of anti-VEGF and semiannual intravitreal injections of the dexamethasone implant. Combining the two treatments into a single drug delivery system (DDS) would reduce the total number of injections, reducing the risk of potential complications (endophthalmitis, retinal detachment, intravitreal hemorrhage, increased intraocular pressure, and cataract) as well as the socioeconomic burden of treatment.The overarching goal of this study was to develop a single DDS that simultaneously releases anti-VEGF (aflibercept) and corticosteroid (dexamethasone) for the treatment of non-responsive wet AMD patients. Our laboratory previously developed a thermoresponsive, biodegradable microparticle-hydrogel DDS that releases anti-VEGF over a period of six months. The aims of the study were to (1) modify this system to include dexamethasone-loaded nanoparticles, optimize release kinetics for both drugs, and characterize the DDS; (2) evaluate the in vivo treatment efficacy in a laser-induced choroidal neovascularization (CNV) model; and (3) investigate the impacts of temperature and storage on the DDS integrity.
Show less

Title: DEVELOPMENT AND EVALUATION OF MRI TEMPLATES OF THE MIITRA ATLAS
Creator: RIDWAN, ABDUR RAQUIB
Date: 2021
Description: Digital human brain atlases play a pivotal role in conducting wide range of neuroimaging studies and are commonly used as references for...
Show moreDigital human brain atlases play a pivotal role in conducting wide range of neuroimaging studies and are commonly used as references for spatial normalization in voxel-wise analysis, region-of interest analyses, automated tissue-segmentation, functional connectivity analyses, etc. A brain atlas typically consists of MRI-based multi-modal templates and semantic labels delineating brain regions according to the characteristics of the underlying tissue. In recent times there has been a plethora of magnetic resonance imaging (MRI) studies on older adults without dementia to explore the role of brain characteristics associated with cognitive functions in old age with the ultimate goal to develop strategies for prevention of cognitive decline. Increasing the accuracy in terms of sensitivity and specificity of such neuroimaging studies require an atlas with a comprehensive set of high-quality templates representative of the brain characteristics typical of older adults and detailed labels accurately mapping brain regions of interest. However, such an atlas has not been constructed for older adults without dementia. Hence this thesis aims to build high quality MRI templates which are the cornerstone resources needed for the development of a comprehensive, high quality, multi-channel, longitudinal, probabilistic digital human brain atlas for older adults termed as Multi-channel Illinois Institute of Technology and Rush University Aging (MIITRA) atlas. This dissertation focuses on a) to develop and evaluate a high performing 1mm isotropic structural T1-weighted brain template, b) to investigate the development and evaluation of a spatio-temporally consistent longitudinal structural T1-weighted template of the older adult brain, c) to develop and evaluate an unbiased 0.5 mm isotropic super-resolved high resolution and detail-preserving structural T1 weighted template of the older adult brain, d) to develop an unbiased 0.5 mm super-resolved high resolution and detail-preserving structural PD weighted and T2-weighted template of the older adult brain, e) to investigate and provide future directions in the development of a 0.5 mm super-resolved high resolution DTI template of the older adult brain, and f) to construct a novel approach in the development of MRI templates using both space and frequency information of spatially normalized older adult data. The thesis based on the aforementioned foundational points was constructed as follows: Firstly, this thesis presents the development of a 1mm isotropic T1-weighted structural template of the older adult brain utilizing state of the art registration algorithm ANTs with parameters carefully optimized for older adults, in an iterative groupwise spatial normalization framework. The preprocessing steps were also thoroughly investigated to ensure high quality data. It was demonstrated through systematic comparison of this new template to several other standardized and study-specific T1-weighted templates that a) it exhibited high image sharpness, b) allowed for high spatial normalization accuracy and detection of smaller inter-group morphometric differences compared to other standardized templates, c) had similar performance to that of study-specific templates and d) was highly representative of the older adult brain. Secondly, with the acquired technical know-how from the aforementioned research findings a new method was introduced for the construction of a spatio-temporally consistent longitudinal template based on high quality cross-sectional older adult data from a large cohort. The new template was compared to templates generated with previously published methods in terms of spatio-temporal consistency and image quality and was shown to have superior performance. In addition, a novel approach was introduced for image quality enhancement of the longitudinal templates utilizing both space and frequency information. Thirdly, the thesis presents a method that involves a) thoroughly refining registration parameters, b) patch-based tissue-guided sparse-representation approach in a super-resolved unbiased minimum deformation space to construct and evaluate an unbiased 0.5 mm isotropic super-resolved high resolution and detail-preserving structural T1 weighted template of the older adult brain. This method accounts for misregistration specially in the cortical regions, ensuring sharp delineation of structures representative of the older adult brain. The new template developed using this approach maintained high anatomical consistency with sharp and detailed cortical features in the brain and exhibited higher image sharpness compared to other high-resolution standardized templates and allowed for high spatial normalization accuracy when used as a reference for normalization of older adult data. Additionally, this approach of template building was investigated on DTI tensors of older adult participants, and the constructed DTI template was shown to perform better than templates developed using the best approach currently present in the literature. Finally, the thesis presents the development of an unbiased 0.5 mm super-resolved high resolution and detail-preserving structural PD weighted and T2-weighted template of the older adult brain, from nonlocal super-resolution based upsampled PD and T2w older adult participant data, using this new template building approach.
Show less

Title: Influence Of Internal Factors In Construction Organizations On The Implementation Of Integrated Project Delivery Viewed From The Organizational Change Theory
Creator: Rashed, Ahmed
Date: 2022
Description: Integrated Project Delivery (IPD) is an emerging construction project delivery system that is collaborative oriented. It involves the critical...
Show moreIntegrated Project Delivery (IPD) is an emerging construction project delivery system that is collaborative oriented. It involves the critical participants in an early stage of the project timeline. Recently, IPD is becoming increasingly common. Many organizations are interested in contributing to the Architecture, Engineering, and Construction (AEC) industry. No research studies have previously observed and studied the effect of IPD implementation through an organizational change theory lens. The presented research work was designed to explore the role of organizational factors in the implementing first domain, reflecting the organizational level factors, including cultural and economic considerations. In contrast, the second domain focuses on member-level factors, i.e., employee involvement and readiness to change. Together, these domains influence the organization’s intention and adoption to change toward the IPD as a project delivery system. This impact is viewed through the lens of the OCT based on the contributions and theories discussed by various researchers. These researchers are from a variety of disciplines. A data collection survey was developed to gather quantitative data from the industry. Data was collected from N=128 employees from the construction industry. Data analysis was performed through Structure Equation Modeling using Smart PLS 3. Results showed that communication, integration significantly associated IPD implementation. Moreover, involvement and readiness change also positively predicted the implementation of IPD. The empirical result of current study validates all the constructs of the hypothetical model except reward system.
Show less

Title: Apalutamide Modulates the Expression of Regulatory Genes for Prostate Cancer Cell Invasion and Migration In Vivo and In Vitro
Creator: Qualter, Gina E.
Date: 2022
Description: The next generation antiandrogen, Apalutamide (Apa), improves both overall survival and metastasis-free survival in men with castration...
Show moreThe next generation antiandrogen, Apalutamide (Apa), improves both overall survival and metastasis-free survival in men with castration-resistant prostate cancer (CRPC). In vitro and in vivo studies were performed to characterize the mechanistic effects of Apalutamide on prostate cancer cell proliferation, invasion, and migration, and the expression of genes that regulate these processes. Apalutamide inhibited the proliferation of LNCaP human prostate cancer cells in both the presence and absence of dihydrotestosterone (DHT), and also inhibited LNCaP cell migration/invasion. At the mRNA level (RT-PCR), Apalutamide down-regulated the expression of androgen receptor (AR), c-Myc, MMP-2, MMP-9, DANCR, and lncRNA, and up-regulated TIMP-2 expression. Similar data were obtained for protein expression (western blot). In the in vivo study, male Hi-Myc mice received daily oral administration of Apalutamide beginning at age 8 weeks for 2 months, 3.5 months, or 5 months. Daily oral administration of Apalutamide reduced accessory sex gland weights by over 50% at all three time points, inhibited the progression of prostatic intraepithelial neoplasms (PIN) to cancer, and significantly affected the expression of genes that regulate invasion and migration. However, in vitro findings indicated that resistance to Apalutamide through the emergence of the AR splice variant 7 (AR-V7) following extended treatment is possible and may be reversed following knockdown of AR-V7 gene expression.In summary, these results suggest that while Apalutamide is an effective inhibitor of prostate cancer invasion/migration, further investigation into the mechanism of AR-V7 mediated Apalutamide-resistance and strategies to overcome resistance may be indicated to improve prostate cancer patient outcomes following extended periods of treatment.
Show less

Title: FACILITATORS AND BARRIERS TO PRE-EXPOSURE PROPHYLAXIS (PREP) UPTAKE WILLINGNESS FOR FULL-SERVICE SEX WORKERS
Creator: Ramos, Stephen D
Date: 2022
Description: Full-service sex workers (FSSW) are individuals who exchange direct sexual services for goods, money, or other services (Centers for Disease...
Show moreFull-service sex workers (FSSW) are individuals who exchange direct sexual services for goods, money, or other services (Centers for Disease Control and Prevention, 2022a). FSSW report relatively poorer physical and mental health compared to others (Ramos et al., 2022; Rekart, 2005). Related, the CDC indicates that due to the nature of sex work, sex workers may be disproportionately at-risk for contracting Human Immunodeficiency Virus (HIV; Centers for Disease Control and Prevention, 2022a). However, a variety of factors may relate to HIV-risk in this population. Specifically, different multi-level factors may relate to sex workers’ willingness to use pre-exposure prophylaxis (PrEP), a once-daily HIV preventative medication (Centers for Disease Control and Prevention, 2022a). While highly effective against HIV, PrEP uptake in several key HIV populations is slow (Holloway et al., 2017). Here, I adapted the Social-Ecological Model (Kaufman et al., 2014), with the assistance of lived-experience members and community organizations in developing and disseminating the study, to assess barriers and facilitators towards PrEP uptake willingness for FSSW and investigated a distal-proximal stigma-based mediation analysis to PrEP willingness. I found that two barriers and two facilitators initially emerged as significant predictor of PrEP uptake willingness. However, in adopting a more conservative approach, only (a) anticipating stigmatizing disapproval from others, and (b) providing others with PrEP knowledge, independently remained as a significant barrier and facilitator to PrEP uptake willingness, respectfully. Mediation analysis did not yield a distal-proximal stigma-based mediation of PrEP uptake willingness. Implications for future research, clinical work, and policy are discussed.
Show less

Title: POLYTRAUMA CLINICAL TRIAD ASSOCIATED ATTENTION AND MEMORY FUNCTIONING
Creator: Ramirez, Amanda M.
Date: 2021
Description: The purpose of the current study was to explore cognitive functioning associated with the polytrauma clinical triad in a sample of post-9/11...
Show moreThe purpose of the current study was to explore cognitive functioning associated with the polytrauma clinical triad in a sample of post-9/11 veterans. More specifically, it sought to determine if a component (i.e., PTSD, mTBI, or pain), in the context of the triad, accounted for variability in attention and memory functioning as measured by neuropsychological assessments. The study also sought to evaluate the relation between PTSD and cognition more comprehensively by examining if the four PTSD symptom clusters were associated with differential patterns of neuropsychological performances. Participants included 111 veterans who served in Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn, otherwise known as post-9/11 veterans. Participants completed a brief structured interview and neuropsychological battery. Several hierarchical regressions examined the association between the polytrauma clinical triad and performances on select measures of attention and memory. Results indicated that the triad did not significantly predict sustained attention, visual memory, or verbal memory. These findings suggested that despite the rates of the polytrauma clinical triad among a significant portion of post-9/11 veterans, the current evidence does not support the presence of related cognitive impairment.
Show less

Title: Contract Rollover and Volatility
Creator: Chen, Yue
Date: 2022
Description: In futures markets, approaching the expiration days, most market participants close out existing positions of front month contract and open...
Show moreIn futures markets, approaching the expiration days, most market participants close out existing positions of front month contract and open new positions of next month contract. The object of this dissertation is to evaluate the impact of contract rollover activities on unconditional volatility and conditional volatility modeling. First, two contract rollover measures, volume ratio and open interest ratio of front contract over next contract are created. Second, this study investigates the impact of contract rollover measures on both unconditional volatility estimation models and conditional volatility estimation models. Third, it examines the roles of contract rollover activities in unconditional volatility prediction models. Last, to further explore the relationship between contract rollover measures and unconditional volatilities, the vector autoregressive model is conducted to test granger causality. The findings show that the volume ratio and open interest ratio have significant impact on unconditional volatilities and conditional volatility in soybean, wheat, gold, copper, crude oil, and natural gas futures markets, except on conditional volatility in silver futures market. Alternative models that incorporate contract rollover measures outperform benchmark models that do not incorporate contract rollover measures in both estimation models and prediction models. Moreover, the findings provide the strong evidence that there is significant bidirectional granger causality among volume ratio, open interest ratio and unconditional volatilities in all investigated futures markets. The empirical results confirm the important role of contract rollover on volatility behavior and are beneficial to futures exchanges to set and monitor margins precisely for their customer’s trading accounts in commodity futures markets.
Show less

repository.iit

Search the repository

Pages

Pages

Enabled Filters

Refine Results

Date

Academic status of creator

Department

Subject

Creator

Rights