Saudi Cultural Missions Theses & Dissertations
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Item Restricted Observer- based numerical schemes(Exeter University, 2024) AlHayzea, Aisha Mousa; Twonley, StuartNumerical analysis and control theory are fundamental areas in engineering and applied mathematics. This thesis explores three concepts from control theory used to enhance classical numerical solvers. The proposed improvement integrates a sampled-data Luenberger observer with a conventional numerical solver in a switched system framework. The method employs the numerical solver when its updates are sufficiently accurate and switches to using process samples to drive an observer when they are not. The switching mechanism is governed by an energy inequality based on a Lyapunov function, potentially triggering sampling as needed. Stability proofs and error estimates utilize input-to-state style stability techniques. This new numerical scheme can handle step sizes significantly larger than those required for the stability of the traditional numerical solver. Additionally, the hybrid approach of switching between the sampled-data observer and the numerical solver can reduce the frequency of sampling needed for accurate observer-based state estimation of the process. In this context, this thesis has the following aims. Firstly, it combined any numerical scheme with sampled-data Luenberger observer in a new hybrid scheme based on switching conditions. The scheme uses the numerical scheme when scheme updates are good enough but switches to an observer driven by process samples when not. A Lyapunov function-based energy inequality determines switching. Thus, the switching condition is central to the hybrid observer-based numerical scheme. The idea underpinning this switching condition is to use a Lyapunov function for the observer as an energy function for the Euler scheme. Loosely speaking, energy for the observer’s solutions will decrease, and we only use the Euler scheme when its energy also decreases. In this sense, the Lyapunov function for the observer becomes a Lyapunov function for the overall hybrid scheme. The switching condition partitions the state space into sections or regions where we use Euler scheme and where we use the observer. Depending on the system and the scheme’s parameters, the region where Euler method is used may be large, small, or even null. Secondly, the aim is to extend the generalized hybrid scheme with a higher-order approximation of the Taylor exponential. We generalize the switched system by using Runge-Kutta. After that, this hybrid ODE solver is constructed by combining the Euler and Luenberger observer to switch from the numerical scheme to the observer when the numerical scheme produces inadequate results. Underpinning our approach is a λ-tracking-based sampled-data observer that invokes a λ dead zone. The resulting hybrid algorithm is a time-stepping numerical scheme. The gains and sampling periods in the sampled data observer are tuned using a λ-tracking approach. Using a sampled-data observer allows process measurements to be only available at some discrete times, while adaptive tuning allows the gains and sampling times to adjust automatically to each other rather than being subject to design. Finally, an alternative switching approach is considered: switching from observer to Euler based on λ and µ strips.5 0Item Restricted Guest Satisfaction The Role of Digital and Contacless Service in the Post Covid 19 Era(Taylor's University, 2025) Alghamdi, Fatimah; Abdulrazak, DhiyaThe COVID-19 pandemic has drastically altered the landscape of various sectors, including the hotel and hospitality industry. With the necessity for social distancing and the resultant increase in digital interactions, hospitality businesses have increasingly adopted digital and contactless service methods. In view of this, this study investigates the role of digital and contactless services in enhancing guest satisfaction in the post-COVID-19 era. It attempts to explore the extent to which these services have promoted guest satisfaction, the challenges encountered in their implementation, and the strategies employed to overcome these challenges. The study will make use of quantitative method with data to be collected from the representatives of the hotel guests in the hospitality sector using random sampling technique based on Israel (2012) sample size. A questionnaire of a 5-point Likert scale is used in this investigation. The data collected are analyzed with the aid of SPSS. The findings show that that satisfaction of guest was high in the post-covid-19 era and that digital service plays an enormous role in ensuring guest satisfaction.1 0Item Restricted Deep Reinforcement Learning for Real-Time Energy Management in Community Microgrids(Lancaster University, 2025) Aldahmashi, Jamal; Ma, XiandongThe integration of renewable energy sources (RESs), energy storage systems (ESSs), and the electrification of transportation are driving a rapid transformation of modern power systems. These changes not only provide great potential to reduce carbon emissions, increase sustainability and improve reliability, but also present complex challenges. Traditional and centralized power systems were originally designed for one-way power flow, from large power plants to consumers, and are becoming increasingly inadequate in the face of intermittent renewable generation, distributed and variable loads, and heightened risks of severe weather disturbances. Thus, intelligent, adaptive and resilient methods for energy management have become a critical priority. In this thesis, I address the need for advanced, real-time control in modern power systems through the use of deep reinforcement learning (DRL) to optimize active and reactive power flows under uncertainty. First, a model-free framework for a single home energy management system (HEMS) that integrates photovoltaic (PV) panels, ESSs, electric vehicles (EVs), and multiple types of residential loads. In contrast to existing methods that focus on active power flows alone, the proposed method optimizes reactive power to improve power factor and avoid possible financial penalties. This framework adapts to fluctuating renewable generation, uncertain EV charging profiles, and the unpredictable behavior of loads by using DRL algorithms that can learn directly from interactions with the environment without explicit mathematical models. Real world data tests show over 30% electricity cost savings and substantial power factor improvements. To extend this concept from individual homes to larger communities, a community energy management system (CEMS) is proposed. Multiple smart homes, each equipped with a HEMS, are interconnected through a point of common coupling to form a community microgrid (CMG). Each home acts as a local agent making autonomous decisions, and a multi-agent DRL (MADRL) architecture is employed to coordinate their actions in a decentralized yet cooperative manner. Further, electricity price forecasting is integrated with a Long Short Term Memory (LSTM) network for proactive scheduling of flexible loads. Simulation results show that this data driven, cooperative control approach can reduce overall community electricity costs by up to 29.66% and keep community voltages more stable than conventional centralized and model-based methods. Also, the proposed MADRL strategy retains decision making at the household level, which provides benefits in terms of privacy, scalability, and adaptability to various grid conditions. The thesis then incorporates optimal power flow (OPF) constraints into the energy management system (EMS) for CMG with high penetration of renewables, ESSs and EVs, recognizing that even larger scale distribution networks require advanced coordination. The work reformulates the OPF problem as a Markov decision process (MDP) and uses a dual-layer DRL structure. The objectives of the first layer controls for continuous control of active power using a twin delayed deep deterministic policy gradient (TD3) algorithm with cost minimization, load shedding prevention and efficient use of DERs. The second layer, which uses a double deep Q-network (DDQN), controls discrete reactive power to maintain voltage stability. This dual-layer approach addresses the challenges of high-dimensional, non-linear, and stochastic power systems. The experiments on a modified IEEE-15 bus system demonstrate up to 10.41% cost savings versus no EMS, with less voltage violations and less load shedding. The dual-layer DRL framework is resilient to stochastic variations in renewable output and load demand, and is a practical candidate for real-time distribution network operations. Overall, the research presented demonstrates that DRL-based solutions, whether applied to individual homes, local communities or larger distribution networks, can successfully deal with the uncertainty and variability of modern power systems. By integrating cutting-edge neural network architectures for price forecasting, multi-agent coordination, and dual-layer control, the proposed methods outperform traditional optimization and control approaches in terms of cost efficiency, voltage stability, and scalability. As a result, these techniques offer great potential for enabling flexible, economically viable, and robust power grid operations. With increasing proportion of RESs, ESSs and EVs, the demand for such intelligent, adaptive and decentralized energy management solutions will increase, leading to a more sustainable and resilient electricity infrastructure.15 0Item Restricted Mindfulness as a Culturally Sensitive Moderator Between Stress and Anxiety in Saudi Female International Students(University of Cincinnati, 2024) Aldosari, Hend Abdullah; Brubaker, MichaelInternational students studying in the U.S. are becoming increasingly more common as students take advantage of new and existing educational opportunities. One of the larger populations of international students in the U.S. are Saudi students. While students face a number of stressors and anxieties related to schooling, Saudi international students face additional stressors related to adapting and acclimating to the new cultural environment. This is especially exacerbated in Saudi women, as they face discrimination based on the way they dress and have additional burdens such as family and childcare. However, culturally sensitive counseling approaches which address this unique population have yet to be fully investigated or developed. Mindfulness is a technique which involves quieting one’s mind and body and reflecting on one’s situation and circumstances without self-judgment. This approach has been used extensively as a technique to reduce and moderate the relationship between stress and anxiety generally and has been found to be effective in international students as well. Furthermore, mindfulness intersects directly with the principles of Islam through its focus on self-reflection and calming one’s mind, making it a culturally sensitive approach for Muslim clients, such as Saudi women. However, the moderating effects of mindfulness on stress and anxiety in Saudi female international students has yet to be investigated. The goal of this dissertation is to review what is known on the effects of mindfulness on stress and anxiety in international students and to investigate the moderating effects of mindfulness on stress and anxiety in Saudi female students in the U.S.10 0Item Restricted Resilience and Reality: Exploring the Lived Experiences of People Living with HIV in Texas During the COVID-19 Pandemic – A Qualitative Study.(The University of Texas at Arlington, 2025-05) Alanazi, Ahmed; Eusebius, SmallThis study investigated the lived experiences of individuals living with HIV (PLWH) in the Dallas-Fort Worth (DFW) area of Texas during the COVID-19 pandemic, using an Interpretative Phenomenological Analysis (IPA) framework. The research examined the intersection of health, social dynamics, and psychological resilience among PLWH, who faced compounded vulnerabilities due to systemic inequities and the dual public health crises of HIV and COVID-19. Through semi-structured interviews with ten participants from diverse backgrounds, the study captured the profound impacts of disrupted healthcare systems, heightened stigma, and social isolation on this marginalized population. The findings reveal that the pandemic exacerbated existing inequities in access to antiretroviral therapy (ART) and mental health services, while simultaneously highlighting the remarkable resilience of the participants. Adaptive coping mechanisms, community support, and advocacy efforts emerged as critical strategies for navigating the layered challenges of living with HIV during a global health crisis. The study identified key themes such as social isolation and estrangement, the emotional toll of the diagnosis, resilience in navigating health crises, and redefining possibilities through HIV services, with each theme branching into sub-themes that offer deeper interpretations. Participants' narratives underscore the necessity for tailored interventions that address the broad-ranging needs of PLWH, including the integration of mental health services into HIV care and the development of socially-led education campaigns to combat stigma. By focusing on the unique experiences of PLWH, this research contributes to the broader understanding of syndemic health crises, where HIV/AIDS interacts synergistically with other social, economic, and health issues, exacerbating the overall impact on affected communities. The study calls for a paradigm shift in public health policy, emphasizing the need for inclusive and intersectional approaches that prioritize equity, resilience, and community empowerment. The findings also provide actionable insights for healthcare providers, policymakers, and community organizations, advocating for robust telemedicine infrastructure, stigma reduction initiatives, and comprehensive support systems that ensure continuity of care during public health emergencies. As the global community still grapples with the lasting impacts of the COVID-19 pandemic, this study underlines the urgency of reimagining public health strategies. By centering the voices of those living at the intersection of HIV and COVID-19, it challenges existing paradigms and paves the way for innovative solutions that transcend individual health crises, offering a blueprint for more equitable, inclusive, and resilient healthcare systems. The research not only highlights the structural inequities that deepen health disparities but also illuminates the resilience and adaptive capacities of PLWH, providing a foundation for policies and practices that uphold dignity, wellbeing, and social inclusion for all.11 0Item Restricted Open Banking Framework: A Comparative Study of Evolving Law in the Kingdom of Saudi Arabia and the United States of America(Indiana University, 2025-05) Alatram, Abdulhamid; Henderson, WilliamOpen banking is reshaping the financial sector by enabling third-party access to consumer financial data and; fostering innovation while raising regulatory challenges. This study compares the legal frameworks that governs open banking in the Kingdom of Saudi Arabia (KSA) and the United States (US), focusing on consumer protection, data privacy, and compliance. KSA adopts a centralized regulatory model under the Saudi Central Bank (SAMA), ensuring uniform compliance, while the US follows a fragmented, market-driven approach with multiple regulators. Through a comparative legal analysis, the study identifies key differences, regulatory gaps, and areas for improvement in transparency, dispute resolution, and responsible data-sharing practices. The findings of this dissertation highlight the need for balanced regulatory frameworks that promote financial innovation while safeguarding consumer rights. This research provides insights for policymakers and industry stakeholders that; advocate for legal reforms that enhance security, efficiency, and consumer trust in open banking ecosystems.10 0Item Restricted Evolutionary Design with Freedom and Rhythm for Heat Transfer, Strength, and Power Utilization(Duke University, 2024) Almahmoud, Hamad; Bejan, AdrianThe thesis combines fundamental studies on the evolution of design and performance in flow fields. The first study investigates the evolving architecture of a composite material with configurable inserts, comparing different shapes such as plates, forks, chains, and diamonds. The inserts, having higher thermal conductivity and lower elasticity than the base material, lead to better performance in thermal conductance and mechanical strength when distributed wisely. Next, the thesis explores tree-shaped flow in a dendritic heat exchanger, examining two flow architectures: parallel orifices and sequential slits. It provides theoretical and numerical analysis on the step-down ratio in the size of the orifices and channels, contributing key design principles for future dendritic heat exchanger systems. The third study broadens the design of heat transfer systems by varying both the fin and flow channel aspect ratios. This comprehensive approach allows for predicting the complete design of high-density heat transfer architectures, providing higher heat transfer rates and lower pumping power. The fourth study is about periodic in-and-out airflow through a single orifice into an enclosure to refresh air quality. Two scenarios of airflow rhythm are analyzed, with findings indicating the optimal time intervals for maximum air replacement and minimal energy expenditure. The fifth study explores animal locomotion and the rhythm of propulsion in frogs and swimmers. The cyclic nature of work and energy dissipation is analyzed, revealing that evolutionary changes in body design and locomotion rhythm enhance power utilization and speed. Together, these studies highlight the role of evolving design principles in optimizing both natural and engineered systems, demonstrating how freedom in configuration and design leads to improved performance across a variety of applications.3 0Item Restricted Islamic Finance, Dividend Policy, and Performance of Insurance Firms(The University of New Orleans, 2025-05) Almoaheem, Yazeed; Hassan, KabirThe dissertation investigates the impact of Covid-19 pandemic and dividend policy on the performance of insurance firms. It examines the impact of the Covid-19 pandemic on the performance of Islamic insurance versus conventional insurance firms in the Organization of Islamic Cooperation (OIC) member countries. Using Dynamic Capabilities theory and Resource Dependence Theory, the study examines the reasons behind the more significant performance reduction in Islamic insurance firms during the pandemic. Using firm- and country-level panel data from 425 insurance firms for 7 years (2016-2022) and employing different regression models, the analysis focuses on Return of Assets (ROA) and Asset Turnover Ratio as performance measures. The results indicate that Islamic insurance firms exhibited a greater reduction in performance, during the pandemic, compared to conventional firms, primarily due to weaker liquidity management and operational flexibility. Cash from operating activities (COA) was the key factor of lack of liquidity management, contributing to the underperformance of Islamic insurance firms during the pandemic. The findings highlight the need for improved liquidity management approaches in Islamic insurance firms to increase their resilience to future economic shocks. The dissertation also investigates the impact of dividend policy on the performance of 688 insurance firms globally from 2014 to 2022. Employing different econometric models, we find that dividend policy significantly increases both accounting (ROAA) and market (MKTCAP) performance. The findings align with the Dividend Signaling Theory and the Agency Theory of Free Cash Flow, which emphasize that dividend payouts signal a stable financial health and mitigate agency problems. Our findings demonstrate that consistent dividend payments (CONDIV) increase ROAA and MKTCAP by 0.007 and 0.139, respectively, which underlines the importance of consistent dividends. Channel analysis shows that corporate governance board committees, CEO duality, and board gender diversity amplify the positive effect of dividend policy, while larger board size diminishes it. This provides a global understanding of dividend policy significant impact on insurance firm performance. Jointly, the dissertation’s findings provide a complete picture to understand the financial decisions and governance structures that affect the performance of insurance firms during economic shocks such as Covid-19 pandemic and on the global stage.28 0Item Restricted Firm Performance Sustainability and Reputation(University of New Orleans, 2025-05) Alharbi, Mohammed; Hassan, M.KabirThe first essay investigates the impact of the COVID-19 pandemic on the performance of Sharia-compliant and non-compliant firms within the Organization of Islamic Cooperation (OIC) member countries. Employing panel data from 337 publicly listed non-financial firms between 2016 and 2022, the research compares profitability and growth metrics, specifically Return on Assets (ROA), Return on Equity (ROE), and firm growth rates. Using ordinary least squares (OLS) and random effects (RE) regression models, the analysis incorporates firm-specific variables. The findings indicate that both Shari'ah compliance and the COVID-19 pandemic negatively impacted firm performance. Sharia-compliant firms experienced significantly greater declines in ROA and ROE compared to non-compliant firms. Furthermore, compliant firms exhibited reduced growth rates, which highlights potential vulnerabilities stemming from ethical financing constraints and conservative investment practices. The interaction between Shari’ah compliance and the COVID-19 pandemic further worsened these adverse outcomes, indicating an increased vulnerability among compliant firms during times of economic disruption. A comprehensive regional analysis has identified that firms in Asia were particularly affected, thereby emphasizing the geographic variations in the impacts observed. The second essay is an empirical study of the relationship between Environmental, Social, and Governance (ESG) performance and corporate reputation. The goal is to address the existing gap in sustainability literature. This study employs a comprehensive panel dataset that includes 4,000 US firms from 2014 to 2023. The aim of this study is to investigate how ESG performance influences corporate reputation through annual and cumulative corporate responsibility awards. The study utilizes various econometric techniques to tackle issues concerning endogeneity and sample selection bias. The econometric techniques include logistic regression, Ordinary Least Squares (OLS), Two-Stage Least Squares (2SLS), Propensity Score Matching (PSM), Entropy Balancing, and Heckman selection models. The results consistently show that companies with better ESG performance are significantly more likely to be acknowledged with corporate responsibility awards. The strength of these findings is supported by various robustness analyses. The study examines how firm-specific characteristics, including company size, financial performance, and research and development, influence the relationship between ESG engagement and reputation outcomes. The evidence indicates that these factors enhance the positive impact of ESG performance on corporate reputation. The findings highlight the strategic value of ESG initiatives for corporate leaders and policymakers, which emphasizes their role in enhancing stakeholder trust and securing long-term competitive advantages.19 0Item Restricted Synthesis and Characterization of Fe (III) Complexes of 8- Hydroxyquinolines and Their Antimicrobial Activity against Staphylococcus aureus and Multidrug-Resistant Staphylococcus aureus(Kent State University, 2025-05) Alidrees, Amjad; Songping, HuangThe emergence of multidrug-resistant bacteria, particularly Staphylococcus aureus and Acinetobacter baumannii, presents an urgent need for new antimicrobial strategies. This research focuses on the synthesis and characterization of novel Fe(III) complexes formed with structurally distinct 8-hydroxyquinoline derivatives: 4-methyl-8-hydroxyquinoline, 5-nitro-8-hydroxyquinoline (nitroxoline), and 7-chloro-5-nitro-8-hydroxyquinoline. The complexes were characterized by UV-Vis spectroscopy, FT-IR spectroscopy, elemental analysis, LC-MS, and single-crystal X-ray diffraction. Their antibacterial activity was evaluated against methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA, MRSA), vancomycin-intermediate S. aureus (VISA), and A. baumannii. Minimum inhibitory concentration (MIC) assays, colony-forming unit counts, intracellular reactive oxygen species (ROS) assays, resistance development studies, hemolysis assays, and checkerboard synergy tests were performed. Results demonstrated that the Fe(III) complexes significantly enhanced antibacterial activity compared to free ligands, primarily by disrupting bacterial iron homeostasis and inducing ROS production. The findings offer promising insights into developing Fe(III)-based antimicrobial agents to combat antibiotic-resistant bacterial infections.20 0