Search results
(7,181 - 7,200 of 10,079)
Pages
- Title
- Intelligent Battery Switching Module for Hybrid Electric Aircraft
- Creator
- Kamal, Ahmad
- Date
- 2022
- Description
-
The growth in world economics, tourism and international cooperation has resulted in significant growth of civil aviation industry. This...
Show moreThe growth in world economics, tourism and international cooperation has resulted in significant growth of civil aviation industry. This growing number of fossil fuel reliant aircrafts will significantly increase waste gas emissions with detrimental impact on the environment. The system efficiency of the aircraft must be substantially improved to reduce the fuel burn and thus waste gas emissions. Therefore, the aircraft industry is pushing towards higher electrification of future aircrafts to increase system efficiency, reduce fuel burn and to lower emissions as well as operational costs. The more electric aircraft (MEA) design concept, commercially realized by Boeing 787 and Airbus A380, increases system efficiency by replacing the mechanical, pneumatic, and hydraulic systems with electrical systems. However, global regulation authorities demand further reduction in waste gas emissions and fuel burn. To meet these stringent demands, the aircraft industry is exploring hybrid electric aircrafts which can significantly reduce fuel burn by electrifying the propulsion train of the aircraft. This higher penetration of electrical energy in the aircraft warrants smart short-circuit protection with ultrafast response time. However, current hybrid aircrafts still use outdated mechanical and thermal short-circuit protection which have historically proven to cause numerous tragedies. Solid-state power controller (SSPC) is an alternate solution which uses semiconductor devices to offer faster response. However, the main drawbacks of SSPCs are their need for active cooling due to higher conduction loss and the use of foldback current limiting approach to limit the inrush current of DC-link capacitor of the powertrain. The foldback current limiting approach degrades the power semiconductor devices used due to excessive heat loss by driving the device near the safe operating area (SOA) limits of the device. This thesis presents a 750V/250A intelligent Li-ion battery switching module (BSM) for hybrid electric aircraft propulsion application. The BSM uses commercially available 1200 V SiC JFET power modules with ultra-low RDSON in parallel to achieve sub-mΩ total on-resistance, comparable to the incumbent mechanical contactor solution. This allows the total nominal conduction power loss of the BSM to be less than merely 23 W, permitting maintenance-free passive cooling. In contrast to the incumbent contactor solution, the BSM has ultrafast response (µs-level) to a fault condition. Which, in conjunction with the reduced fault current stress, significantly improves the operation lifetime of the entire system. The BSM incorporates various intelligent features by implementing a tri-mode operation concept, which allows to pre-charge the DC-link capacitor with a limited charging current in PWM mode. To mitigate single-point failures, several design redundancy measures are implemented to ensure reliability and safety for the aircraft. Design considerations of the circuit and physical design of the BSM are discussed in detail including the design of the custom laminated busbar and thermal analysis. Furthermore, the inherent uncontrolled oscillation phenomenon of the JFET cascode structure is explored and addressed. Finally, the experimental results obtained from the built and tested prototype of the BSM are reported.
Show less
- Title
- Examining Associations Between Discrimination, Social Cohesion, and Health among White and POC LGBT Chicagoans
- Creator
- Kannout, Lynn
- Date
- 2022
- Description
-
Consistent with the minority stress perspective, lesbian/gay, bisexual, and transgender (LGBT) individuals on average report worse health than...
Show moreConsistent with the minority stress perspective, lesbian/gay, bisexual, and transgender (LGBT) individuals on average report worse health than heterosexual individuals in several domains, e.g., general health, mental health, physical health, and health care access. Intersectionality-based research shows that LGBT-POC are, on average, at even greater risk for adverse health outcomes compared to their White LGBT counterparts. Discrimination and social cohesion may be two mechanisms underlying these between- and within-group disparities, given their broader relations to health and their relatively high frequency within marginalized populations. This study used data from the Chicago Department of Public Health to examine broad health differences between LGBT White and LGBT-POC individuals, and to test specific mediations models in which social cohesion mediated links between discrimination and health. LGBT-POC reported experiencing worse general health, lower access to health care, more experiences of discrimination, and lower feelings of social cohesion than did White LGBT individuals. No mediation effects emerged, however there was a direct effect of experiencing discrimination on mental health distress. Further, discrimination exposure related inversely to feelings of social cohesion. Study strengths, limitations, and implications are discussed.
Show less
- Title
- Predictive Energy Management of Connected Hybrid Electric Vehicles in the Presence of Uncertainty
- Creator
- Sotoudeh, Seyedeh Mahsa
- Date
- 2022
- Description
-
Energy efficiency improvements brought by electrification of the powertrain in Hybrid Electric Vehicles (HEVs) highly depend on their...
Show moreEnergy efficiency improvements brought by electrification of the powertrain in Hybrid Electric Vehicles (HEVs) highly depend on their powertrain Energy Management Strategy (EMS) that determines optimal power allocation between powertrain components.Eco-driving based EMS seeks further energy efficiency improvements through optimizing vehicle's driving cycle (velocity and hence torque demand), in addition to the powertrain's EMS. A novel hierarchical EMS is developed in this thesis for connected human-driven HEVs and then extended to automated HEVs that effectively addresses some of the major challenges of the energy management problem. At its high-level, a computationally-tractable Pseudospectral Optimal Controller (PSOC) with discounted cost is employed to approximately solve the powertrain's energy management problem over driving cycle previews of the entire trip. The high-level's approximate solution is then used as a reference by the low-level tube-based Model Predictive Controller (MPC) that solves the problem over higher-quality, short-horizon driving cycles in a real-time applicable fashion. For human-driven HEVs, a Long Short-Term Memory (LSTM) neural network predicts the human driver's velocity profile over low-level's short horizons. A velocity optimizer is added to the low-level for automated HEVs that optimizes the vehicle's driving cycle by effectively utilizing regenerative braking capability of the HEV. At the low-level, the tube-based MPC controller solves the powertrain's energy management problem over either predicted (human-driven HEV) or optimized (automated HEV) driving cycles by accounting for driving cycle's uncertainty, due to uncertain future information, and hence ensures robust constraints satisfaction. A novel cost-to-go approximation method is developed that uses the optimal costate trajectories obtained from the high-level PSOC controller to generate terminal costs for the low-level controller. This improves suboptimality of the short-horizon solutions and ensures charge balance constraint satisfaction at the end of the trip without having to impose conservative constraints. A novel learning-based framework is also proposed to jointly optimize the automated HEV's driving cycle and its powertrain's power split. A Deep Neural Network (DNN)-based MPC controller is developed for the low-level that jointly optimizes the HEV's driving cycle and powertrain energy management in a real-time applicable manner. To ensure constraints satisfaction, a novel Quadratic Programming (QP)-based projection of the DNN-based approximate control laws is proposed that can be efficiently solved in real-time. Simulation results over standard and real-world driving cycles demonstrate efficacy of the proposed control frameworks in terms of suboptimality (fuel efficiency) improvement, potential real-time applicability, and constraints (especially charge balance constraint) satisfaction in the presence of driving cycle uncertainty.
Show less
- 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
- Biophysical and Computational Characterization of CinDel Edits of Dystrophin
- Creator
- Stojkovic, Vladimir
- Date
- 2022
- Description
-
Duchenne muscular dystrophy (DMD) is a degenerative genetic disease caused by a genetic defect that results in the absence of dystrophin, a...
Show moreDuchenne muscular dystrophy (DMD) is a degenerative genetic disease caused by a genetic defect that results in the absence of dystrophin, a protein with an important stabilizing role in muscle cells. DMD causes progressive muscle degeneration leading to the loss of ambulation, and typically results in death before the third decade of life. Treatments for DMD aim to restore dystrophin expression and typically do so by producing edited or modified dystrophins. The only FDA approved therapy, exon skipping, produces dystrophin edits at exon boundaries but emerging therapeutic approaches like gene replacement therapy and CRISPR-Cas9-based gene editing techniques like CinDel allow for greater flexibility and are not constrained to exon boundary edits. However, understanding of what makes a “good”, functional edit is limited so it is not clear how to make use of this increased flexibility to produce optimal edits which are believed to be necessary for robust treatment. In an effort to improve understanding of the biophysics of these non-exon edits, we have embarked on a mixed experimental and computational study of a set of CinDel edits in the D19-D21 region of the dystrophin central rod domain. First, we have conducted an Alphafold structure prediction-based screen of a subset of possible edits in this region and selected one edit for follow-up characterization. We then compared this computationally-selected edit to three other heuristically designed edits experimentally and computationally by molecular dynamics simulations. We found that the computationally selected edit is significantly more thermodynamically stable than the other edits in the cohort. This edit also generally exhibited more favorable properties in MD simulations across multiple measures such as helicity, STR-junction unwinding and conformational variability.
Show less
- Title
- Health Information Seeking, Depression, and Satisfaction with Life in Racial/ethnic Minority vs. White individuals with Spinal Cord Injuries
- Creator
- Stipp, Kelsey
- Date
- 2022
- Description
-
Health information is available both traditionally by conversations with health care professionals, and non-traditionally via use of the...
Show moreHealth information is available both traditionally by conversations with health care professionals, and non-traditionally via use of the Internet and other media sources. Health information is crucial to individuals with chronic health conditions and/or disabilities, such as spinal cord injury (SCI), to promote health, minimize comorbidities, and improve quality of life (QOL). Methods of health information seeking have been shown to differ between individuals who are racial/ethnic minority individuals and individuals who are White. Existing research appears to show health information seeking may increase QOL in populations with chronic health conditions and/or disabilities. However, it is unclear how aspects of QOL differ between individuals within the SCI population by race/ethnicity. The present study used Chi Square analyses to test racial/ethnic group differences in health information seeking and multiple analysis of covariance (MANCOVA) to test whether method of health information seeking and aspects of QOL, specifically depression and satisfaction with life, were moderated by race/ethnicity. An adult sample of 9,403 individuals with SCI who completed a survey on their injury, health, and QOL between 2011 and 2016 was used. Participants identified their source of health information as traditional (i.e., conversations with health care professionals) or non-traditional (e.g., newspaper, television, radio, etc.). Results indicated non-traditional sources of health information were utilized more frequently regardless of race/ethnicity. Unexpectedly, moderation results suggested that associations between source of health information and depression and satisfaction with life did not differ by race/ethnicity. However, source of health information was associated with satisfaction with life and depression for the entire sample. Study findings demonstrate the shift towards non-traditional (e.g., newspaper, television, radio, etc.) health information seeking within the SCI population. Further, findings support previous empirical work demonstrating the association between method of health information seeking and depression and satisfaction with life. These findings can be used to improve dissemination of accurate health information to the SCI population via non-traditional sources. Further research should include more diverse samples of individuals to better understand health information seeking as well as depression and satisfaction with life within the SCI population.
Show less
- Title
- A Functionalized 2D Boron Nitride Electrode for Rechargeable Batteries
- Creator
- Tatagari, Vignyatha Reddy
- Date
- 2021
- Description
-
Motivated by the great performance of the graphene oxide battery and its poor safety, in the present work, an attempt is made to fabricate an...
Show moreMotivated by the great performance of the graphene oxide battery and its poor safety, in the present work, an attempt is made to fabricate an alternative battery from functionalized 2-dimensional (2D) boron nitride. The expectation is that functionalized boron nitride can exhibit the same great electrochemical performance as graphene oxide while it would be much more thermally stable. Toward this goal, synthetic opportunities were explored to realize -OBF3 functionalized hexagonal boron nitride. Both top-down and bottom-up synthetic approaches were considered and implemented. In the top-down methods, commercially available bulk hexagonal boron nitride (h-BN) is reacted with functionalization agents such as LiOBF3 and LiOH.BF3. Synthesis of these functionalization agents and their reactions with h-BN were carried out in several different ways. Bottom-up synthetic approach using Boric Acid and Urea was utilized to synthesize turbostratic boron nitride (t-BN), which is an intermedier in the commercial synthesis of hexagonal boron nitride. Turbostratic boron nitride contains exfoliated and -OH functionalized monolayers of boron nitride. An attempt is made to esterify the -OH groups of turbostratic boron nitride to obtain the desired -OBF3 functionalized monolayers of h-BN. Initial electrochemical tests on turbostratic boron nitride and its esterified form are carried out along with ionic conductivity measurements. Only a very limited electrochemical activity was observed due to a low degree of functionalization in these materials, indicating the need for improved synthetic procedures to achieve the desired target materials.
Show less
- Title
- PIMMINER: A HIGH-PERFORMANCE PIM ARCHITECTURE-AWARE GRAPH MINING FRAMEWORK
- Creator
- Su, Jiya
- Date
- 2022
- Description
-
Graph mining applications, such as subgraph pattern matching and mining, are widely used in real-world domains such as bioinformatics, social...
Show moreGraph mining applications, such as subgraph pattern matching and mining, are widely used in real-world domains such as bioinformatics, social network analysis, and computer vision. Such applications are considered as a new class of data-intensive applications that generate massive irregular computation workloads and memory accesses, which degrade the performance and scalability significantly. Leveraging emerging hardware, such as process-in-memory (PIM) technology, could potentially accelerate such applications. In this paper, we propose PIMMiner, a high-performance PIM architecture graph mining framework. We first identify that current PIM architecture cannot be fully utilized by graph mining applications. Next, we propose a set of optimizations that enhance the locality, and internal bandwidth utilization and reduce remote bank accesses and load imbalance through cohesive algorithm and architecture co-designs. We compare PIMMiner with several state-of-the-art graph mining frameworks and show that PIMMiner is able to outperform all of them significantly.
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
- 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
- CHARACTERIZATION OF HERBS AND SPICES PHYTOCHEMICALS AND PHARMACOKINETIC PROFILE OVER 24-HOUR AFTER CONSUMPTION IN OVERWEIGHT/OBESE ADULTS
- Creator
- Huang, Yudai
- Date
- 2022
- Description
-
The health benefits of herbs and spices (H/S) have been known since ancient times. They are a rich source of phytochemicals, such as phenolic...
Show moreThe health benefits of herbs and spices (H/S) have been known since ancient times. They are a rich source of phytochemicals, such as phenolic compounds and terpenoids. However, there is limited information on their absorption and metabolism in humans. Therefore, the primary objective of this study is to identify and characterize phytochemical compounds in H/S mixtures and their absorption and metabolism in the human body over 24 h. H/S and plasma samples used in this study were from a randomized, single-blinded, 4-arm, 24 h, multi-sampling, single-center crossover clinical trial (Clincaltrials.gov NCT03926442) conducted in obese or overweight adults (n=24, aged 37 ± 3 years, BMI=28.4 ± 0.6 kg/m2). Plasma samples were collected at baseline (t=0 h), 0.5, 1, 2, 4, 5.5, 7, and 24 h after consuming a high-fat high-carbohydrate (HFHC) meal with salt and pepper (control) or the control meal with 6 g of three different H/S mixtures (Italian herb: rosemary, basil, thyme, oregano, and parsley in the same ratio; cinnamon; and pumpkin pie spice containing cinnamon, ginger, nutmeg and allspice, the ratio unknown). The phytochemical compounds in the H/S mixtures and their metabolites in human plasma were tentatively identified and quantified by dynamic multiple reaction monitoring transitions on UHPLC-QQQ-MS/MS. Statistical analysis was conducted on SAS-PC 9.4 using non-parametric test via NPAR1WAY procedure. A total of 79 phytochemical compounds were quantified from samples of three H/S mixtures and pepper, of which 36 were flavonoids conpounds, 8 were terpenoids, 27 phenolic acids, and 9 were identified as other compounds. Acetone showed the highest extraction ability for both (poly)phenols and terpenoids in H/S compared to other organic solvents (50% and 80% methanol, ethyl acetate and chloroform). Italian herb contains 763.1 mg/100 g flavonoids, 879 mg/100 g phenolic acids, and 498.6 mg/100g terpenoids; cinnamon contains 981 mg/100 g flavonoids, 11.2 mg/100g phenolic acids, 292.3 mg/100g coumarin, and 1977.1 mg/100 g cinnamaldehyde; pumpkin pie spice contains 655.8 mg/100 g flavonoids, 17.1 mg/100 g phenolic acids, 226.5 mg/100 g coumarin, and 1633 mg/100 g cinnamaldehyde. A total of 47 metabolites were tentatively identified and quantified in plasma samples after H/S consumption over 24 h. Plasma concentrations of carnosic acid derivatives and the glucuronidation products increased after intake of Italian herb, and the Area under the curve (AUC0-24h) was significantly different from control (all P < 0.05) except carnosol glucuronide. Carnosic acid and carnosol had Tmax at 3.4±1.1 and 1.8±0.3 h, respectively, while both of their conjugated glucuronides kept increasing until 24 h. Coumarin glucuronide was increased by cinnamon and pumpkin pie spice consumption with peak concentrations reached at between 1.5-1.6 h. The AUC0-24h after both meals were significantly different from control meal, both P < 0.05. Our results suggest that H/S contain diverse categories of phytochemical compounds that are absorbed and metabolized in the human body into various metabolites in response to 3 different H/S test meals and their appearance in the blood starts as early as around 0.5 h and extends to as long as 24 h for select metabolites.
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
- 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
- Title
- INFORMATION EFFICIENCY AND THE EFFECT OF HIGH FREQUENCY TRADING IN THE U.S. FUTURES MARKETS
- Creator
- CHA, SEUNG YOUN
- Date
- 2021
- Description
-
The paper gives an empirical analysis with the U.S. futures market data on how High Frequency Trading, HFT can improve the information...
Show moreThe paper gives an empirical analysis with the U.S. futures market data on how High Frequency Trading, HFT can improve the information efficiency of asset prices. Various analyses were conducted to determine the degree of efficiency of information in futures high-frequency trading. The paper tries to explain the effect of high-frequency trading on the efficiency of the market in various ways and tries to propose stepping stones for developing a new market analysis measure.The research builds a coherent framework for analyzing both linear and non-linear market efficiency and applies it to a variety of futures contracts using high- frequency data. The major finding of this paper is that market efficiency levels vary widely over time depending on market characteristics. The paper also finds that HFT activities are higher when the market is inefficient. The paper analyzes the relationship between high frequency trading activities and market efficiency and discovers the mechanism. The story that HFT activity responds to market efficiency needs is especially strong in the E-mini, S&P500 futures contract.
Show less
