Saudi Cultural Missions Theses & Dissertations
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Item Restricted Design, Modeling, and Experimental Verification of Passive Microwave Circuits for Future Wireless Communication(Saudi Digital Library, 2025) Alshehry, Abdulrahman Awad Abdullah; Darwazeh, IzzatThe rapid expansion of high frequency wireless communication systems requires microwave circuits and antennas that combine compactness, low cost, and excellent spectral purity. This thesis addresses these challenges through the design, modeling, fabrication, and experimental verification of passive microwave circuits tailored for next generation wireless networks. This work focuses on designing and testing passive structures aimed at optimizing harmonic suppression and impedance control, while ensuring their compatibility with radio frequency and electro optic measurement setups. The research begins with an investigation of surface wave phenomena and metasurface concepts, which provide a foundation for compact passive designs. Novel surface wave launchers and guided wave structures were modeled, fabricated, and tested, demonstrating efficient propagation and low insertion loss across targeted frequency bands. Reconfigurable metasurfaces were further explored to enable adaptive filtering and radiation control, offering opportunities for tunability in wireless front end applications. Building upon this foundation, several classes of microstrip filters were designed, including stepped-impedance low-pass filters, parallel-coupled-line band-pass filters, and cascaded hybrid networks. These filters were optimized for operation at 2.5 GHz, 5 GHz, 6.25 GHz, 10 GHz, and 25 GHz, with particular emphasis on suppressing spurious harmonics. A dual-stage cascaded topology, combining low-pass and band-pass sections, was introduced to achieve broadband rejection of unwanted harmonics while preserving low insertion loss. All circuits were fabricated using standard PCB processes and inspected under optical microscopy to confirm the fidelity of fine-line features. A key contribution of this work lies in the experimental verification of harmonic suppression in combined RF and optical systems. Fabricated filters and patch antennas were integrated into optical frequency comb setups employing phase and Mach Zehnder modulators. By aligning microwave filter responses with the generated comb spectra, significant suppression of harmonic content was demonstrated. Phase noise measurements further confirmed that the proposed architectures reduce spurious sidebands, leading to improved spectral purity and enhanced synchronization performance. These results are directly relevant for emerging millimeter wave wireless links, high capacity backhaul, and photonic–assisted communication systems. Comprehensive measurement campaigns were conducted using vector network analyzers, spectrum analyzers, tunable lasers, and phase–noise analyzers. The fabricated prototypes consistently validated the theoretical and simulated predictions, with measured results showing strong agreement with full wave electromagnetic models. The integration of passive microwave filters with optical hardware highlights the interdisciplinary scope of the thesis, bridging traditional RF design with modern photonic experimentation. In summary, this thesis makes several original contributions to the design and validation of passive microwave circuits for future wireless communication. These include (i) the development of compact surface wave and metasurface based structures, (ii) the design and fabrication of multiple generations of harmonic–suppressing filters, (iii) the proposal and demonstration of cascaded filter architectures for broadband harmonic rejection, and (iv) the experimental integration of passive circuits with electro optic frequency comb systems to verify improvements in spectral purity. Together, these advances provide new tools for addressing the spectral and integration challenges facing next generation wireless networks. Future directions include extending these methods toward miniaturized multi band solutions, reconfigurable filtering platforms, and machine learning assisted design frameworks.4 0Item Restricted Modelling and Optimisation of The Continuous Pharmaceutical Manufacturing Process: A New Data-Driven Approach For Right-First-Time Production(Saudi Digital Library, 2025) Deebes, Motaz; Mahfouf, MahdiPharmaceutical industries, like most industries, are subjected to stringent quality and regulatory requirements to ensure the manufacturing of safe and high-quality medicinal products. Continuous manufacturing has emerged as a transformative approach offering the potential to meet global demands of medicines through efficient and continuous processes. However, its adoption in tablet manufacturing remains constrained by the complex, multivariate behaviour of particulate processes. Moreover, the lack of comprehensive modelling frameworks further hinders understanding and control of the multistage processes. This thesis aims to develop and evaluate novel predictive modelling frameworks tailored to the continuous manufacturing of pharmaceutical tablets, using data collected from an industrial-scale pilot plant (Consigma-25) encompassing five critical unit operations. An integrated and sequential modelling framework was constructed using ensemble machine learning techniques, including gradient boosting machines and random forests, to predict key quality attributes across stages, with Gaussian mixture models incorporated to reduce uncertainties. To enhance interpretability, a hybrid modelling approach combining artificial neural networks with interval type-2 fuzzy inference system was developed. Additionally, a novel integration of Adaptive Neuro-Fuzzy Inference System with a Genetic Algorithm formed the basis of a model-informed optimisation strategy, enabling the identification of optimal process settings to control the final product quality under “Right-First-Time” manufacturing. The results demonstrate that proposed frameworks were effective in capturing the non-linearity among process parameters and quality outcomes, achieving R2 values exceeding 0.90 across the frameworks. This represents a predictive capability improvement of 56% compared with prior studies. The incorporation of interpretable, uncertainty-aware methods ensured model outputs remained effective to illustrate the processes' understanding despite complexity. The model-informed optimisation strategy was validated through practical application within the right-first-time manufacturing concept. These research findings demonstrate the potential of the proposed frameworks to advance pharmaceutical tablet manufacturing by bridging the gap between scientific research innovation and scalable industrial implementation.9 0Item Restricted BUSINESS ANALYSIS REPORT (BAR) Rolls-Royce Holding Plc Vs BAE Systems Plc(Saudi Digital Library, 2025) ALMAIMAN, FAISAL HAMAD; Chaya, JayathilekaA detailed comparative analysis of Rolls-Royce Holdings Plc and BAE Systems Plc has been undertaken in the aerospace and defense industries in the United Kingdom. This study considers their strategic positioning, financial performance, and responses to changes in their environment between 2020 and 2024. Being a core designer and manufacturer of aerospace propulsion systems, it has undergone major restructuring because of its high risk involved in the downturn of civil aviation in the wake of the COVID-19 pandemic. Hence, strategic initiatives have been placed on sustainable innovations including small modular reactors as well as hybrid-electric propulsion, indicating a transition towards long-term adaptability. Through diversification in defense, BAE Systems has been steadily growing with the support of steady government contracts and developments in cyberspace and electronic conflict. The methodology is an integration of SWOT analysis, financial ratio analysis, vertical and horizontal analyses, with valuation methodologies comprising discounted cash flow (DCF) and relative valuation. Results show steady profits generated through asset utilization efficiency and financial resilience on the part of BAE Systems, whereas Rolls-Royce, showing evidence of recovery momentum, continues to be hampered by high leverage and dependence upon cyclical civil aerospace demand. Sensitivity analysis suggests how Rolls-Royce tends to be more exposed to macro volatility while BAE, in contrast, benefits from relatively steady defense-sector revenues. The findings describe two divergent company trajectories, presenting Rolls-Royce as a high-risk, innovation-led company under transformation, while BAE Systems performs like a stable, contract-secured company with steady returns. The analysis provides an important perspective for industry investors, policymakers, and participants with an understanding of the opportunities and risks present in an industry that has undergone considerable technological change, sustainability implementation, and geopolitical uncertainty.5 0Item Restricted Comparing Fit Accuracy of Gold Crowns Made Conventionally, by CAD-CAM, and 3D Printing(Saudi Digital Library, 2025) Alwasel, Abdullah; Patrick, DavidAim: This study aimed to compare the marginal fit accuracy of gold crowns fabricated using three techniques: conventional lost-wax casting, CAD/CAM milling, and 3D-printed wax patterns. Materials and Methods: A standardised maxillary molar die with a chamfer margin was used to produce 33 wax copings (11 per group). Following inspection for defects, the best 10 copings from each group were cast in high-gold-content alloy. Nine crowns per group were selected for final analysis. Marginal gaps were measured at eight reference points per crown using two methods: manual stereomicroscopy and digital Crown Fit software. Statistical analysis included descriptive statistics, one-way ANOVA, and post hoc Tukey’s HSD tests with a significance level of p ≤ 0.05. Results: Manual stereomicroscope measurements showed mean marginal gaps of 12.22 µm (milling), 77.23 µm (3D printing), and 195.15 µm (conventional). Digital software measurements recorded higher values overall: 61.68 µm (milling), 66.75 µm (3D printing), and 252.99 µm (conventional). Both methods revealed statistically significant differences among the groups (p < 0.001). While milling consistently achieved the smallest gaps with the lowest variability, 3D printing demonstrated clinically acceptable though less consistent results. The conventional method produced the largest gaps and highest variability. Conclusion: Milling provided the highest accuracy and consistency under controlled in vitro conditions, although the extremely low values may reflect laboratory idealisation rather than true clinical performance. 3D printing achieved clinically acceptable fits but was more variable, underscoring the importance of optimised protocols. The conventional method, despite larger discrepancies, remains clinically serviceable, as supported by long-term evidence. Overall, both digital techniques offer promising alternatives, but further validation under intraoral conditions is recommended.6 0Item Restricted Conceptualising Teacher Professional Development in the Context of the Saudi Reform Vision 2030: A mixed-methods Approach(Saudi Digital Library, 2025) Maeni, Latifah; Wilkins,Chris; Baldry, FayThis study aims to explore teachers’ perceptions of the influence of professional development (PD) on their skills, knowledge, and practice, along with the broader contextual factors that influence their participation in and implementation of PD within the framework of Saudi educational reform Vision 2030. The main research question that underpins this study is: What are teachers’ perceptions of professional development in light of the Saudi Vision 2030? Drawing on Opfer and Pedder’s (2011) theoretical framework, the study conceptualises teacher PD as shaped by the interactions between and within individual teachers, learning activities, and school contexts. reform-related initiatives was purposefully selected. This study employed a mixed-methods approach and was conducted in two phases in one public high school in Saudi Arabia. The first phase was quantitative, conducted through an online questionnaire, and involved a total of 25 out of 35 teachers. The second phase was qualitative and conducted via face-to-face, semi-structured interviews with 27 stakeholders, including 17 teachers, a school leader, a deputy leader, and 8 educational supervisors. of national PD policies and The questionnaire was analysed using by applying thematic analysis. A document analysis descriptive statistics, while the qualitative data was analysed The findings revealed that understanding teacher PD is not a matter of examining factors related to teachers, learning activities, or school contexts in isolation, but instead requires attention to the interactions within and between them and the wider professional environment that can both enable and constrain teacher learning. This study calls for the need to move beyond a “one size fits all” approach to teacher PD toward an approach that is more coherent, flexible, contextually relevant, and responsive to teachers’ evolving needs. Implications for policy and practice as well as recommendations for future research were drawn from the findings of this study.4 0Item Embargo Comparative Study of the Performance of an Artificial Intelligence Platform in Detecting Periapical Radiolucencies Across Different Imaging Modalities(Saudi Digital Library, 2025) Allihaibi, Marwa; Koller, Garrit; Mannocci, FrancescoAim: This thesis aimed to evaluate the diagnostic accuracy of a commercial artificial intelligence (AI) platform in detecting periapical radiolucencies (PARLs) across different imaging modalities. The evaluation included preoperative assessment of teeth requiring primary endodontic treatment with comparison against dental professionals, radiographic healing assessment at follow-up, and assessment of teeth referred for apical microsurgery. Methods: Five retrospective diagnostic accuracy studies were conducted to evaluate the commercial AI platform Diagnocat (versions 1.0 and 2.0) for PARL detection across multiple imaging modalities. The studies utilised radiographic data from patients treated at Guy's and St Thomas' NHS Foundation Trust between 2012-2023. The study sample included: (1) 339 teeth indicated for primary root canal treatment, assessed on periapical radiographs (PARs) and compared with two experienced endodontists; (2) 376 teeth assessed at minimum one-year follow-up on PARs for radiographic healing outcomes, compared with two endodontists; (3) 134 molars evaluated on cone-beam computed tomography (CBCT) for preoperative and postoperative assessment; (4) 177 posterior teeth requiring primary endodontic treatment, assessed on PARs and compared with eleven general dental practitioners (GDPs); and (5) 116 anterior teeth referred for apical microsurgery, evaluated on both PARs and CBCT. Reference standards varied by study design: CBCT for PAR validation, expert consensus for CBCT assessment, and histopathology for cases referred for apical microsurgery. Statistical analyses included calculation of sensitivity, specificity and accuracy with 95% confidence intervals. McNemar's test assessed diagnostic performance differences. Subgroup analyses examined performance across anatomical variables. Results: Across five retrospective studies, Diagnocat demonstrated significant performance variability dependent on imaging modality, anatomical location, and treatment status. On PARs, for non-root-filled teeth requiring primary root canal treatment, sensitivity was 47.9% and specificity 95.4%, indicating reliable exclusion of disease but missing over half of actual lesions. In root-filled teeth assessed at one-year follow-up, sensitivity increased to 67.3% while specificity decreased to 82.3%, suggesting altered diagnostic thresholds based on treatment status. Performance on CBCT scans of molars showed marked improvement, achieving 93.9% sensitivity and 65.2% specificity in preoperative cases, and 88.6% sensitivity and 63.3% specificity in follow-up cases. While three-dimensional (3D) imaging substantially enhanced sensitivity for posterior teeth, it was accompanied by reduced specificity, indicating potential for overdiagnosis. Anatomical analysis revealed consistent underperformance in maxillary teeth and specific roots on PARs, limitations that were largely resolved on CBCT for posterior teeth. In contrast, anterior teeth demonstrated persistently poor performance regardless of imaging modality, achieving only 63.8% sensitivity on PARs and 57.5% on CBCT despite histopathological confirmation of periapical pathology. Cross-modality consistency was poor, with only 43.8% of lesions detected on both imaging modalities. Compared to clinicians, Diagnocat showed lower sensitivity (47.9% vs 65.3%) but comparable specificity (95.4% vs 97.7%) when assessed against endodontists in non-root-filled teeth. In root-filled teeth, this pattern reversed, with the AI achieving higher sensitivity (67.3% vs 49.3%) but lower specificity (82.3% vs 92.5%). When compared with GDPs, Diagnocat demonstrated lower sensitivity (44.9% vs 80.8%) but markedly superior specificity (94.3% vs 47.5%). Re-evaluation with version 2.0 showed no improvement in PARL detection across 1,308 PARs and 268 CBCT scans. Conclusion: This thesis demonstrated that multiple factors critically determine AI diagnostic accuracy for PARL detection, including imaging modality, anatomical location, and treatment status, thus highlighting fundamental limitations in training data representation and model development. AI platforms require comprehensive training on datasets with balanced anatomical representation and the incorporation of three-dimensional imaging before being considered for reliable implementation in endodontic diagnosis.8 0Item Restricted Beyond the Desert and the Veil?(Saudi Digital Library, 2025) Alalola, Dema; Johnston, David; Khalifa, Abdel-WahabThis thesis explores textual and visual representations of the Saudi people, Saudi culture, and Saudi Arabia as a country in three Anglophone memoirs, published in 1991, 2009, and 2019. This thesis conducts an investigation of the discursive practices used to construct such representations, with the main aim of examining the nature of Saudi representation as a presumed Other, how this came to be, and what factors influence its construction. This study is based, largely, on the theoretical work of Stuart Hall (1997) and his understanding of representation. The examination of data is conducted through an application of a mixed-method approach to data analysis. The textual analysis will draw on Ruth Wodak’s discourse-historical approach(Reisigl & Wodak, 2005), investigating how the five proposed discursive strategies of this approach construct the representations about Saudi Arabia in Anglophone discourse. Analysis of visual representations follows the Kress and Van Leeuwen (2006) method of grammar of visual design, in order to explore the meaning of the images (cover images) used to represent Saudi Arabia. The findings of this study demonstrate the complex and constructed nature of representation and how representations of Saudi Arabia operate within a closed circle of interpretation that emerges from an orientalist master discourse. In addition, this thesis shows the remarkable consistency in the manner in which Saudi Arabia has been represented in Anglophone discourse. These findings contribute towards highlighting the importance of historical contextualisation in the analysis of discourse and understanding the hidden cultural and ideological factors that shape this representation, which in turn shapes the social reality of the presumed Other.2 0Item Restricted Speech-Language Therapists’ Perspectives on AAC Service Delivery in Saudi Arabia: Barriers, Facilitators, and Training Needs(Saudi Digital Library, 2025) AlThobiani, Farah Saud; Fryer, DanielBackground: Individuals with complex communication needs (CCN) often rely on augmentative and alternative communication (AAC) to support or replace natural speech. While AAC effectiveness depends on clinician expertise, family support, and access to appropriate tools, evidence indicates persistent barriers worldwide. In Saudi Arabia, AAC service delivery remains largely underexplored. Limited training, restricted availability of linguistically appropriate tools, and inconsistent funding have been identified as key challenges, yet little is known about how speech-language therapists (SLTs) perceive current practice. Aims: This study explores SLTs’ perspectives on AAC service delivery in Saudi Arabia, focusing on challenges, facilitators, and training needs. It examines their views on current practice, clinical and patient-related factors, confidence level in AAC implementation, and training backgrounds. Methods: A cross-sectional survey design was employed, with thirty SLTs in Saudi Arabia recruited through snowball sampling. Participants completed a bilingual online questionnaire comprising 40 items for AAC providers and 20 for non-AAC providers. Quantitative data were analysed descriptively, and qualitative responses were analysed using thematic analysis. Results: Of the 30 participants, 25 provided AAC services, most often using low-tech boards and unaided strategies. Reported barriers to service provision included limited funding, lack of AAC tools, insufficient multidisciplinary cooperation, and inadequate training. Over 70% had encountered AAC abandonment, attributed to caregiver noncompliance, preference for speech, social stigma, and device malfunction. Confidence in AAC implementation varied, with most respondents rating themselves as “neutral” or “somewhat confident”. All participants reported a need for further AAC training, favouring workshops and supervised practice. Conclusion: AAC service provision in Saudi Arabia is hindered by limited awareness, restricted availability of Arabic-language tools, inadequate funding, and insufficient SLT training. These findings underscore the need for targeted professional development, caregiver engagement, and community awareness initiatives. Policy-level support is also essential to ensure equitable access to AAC services across the country.5 0Item Restricted Charactersitics of Effective Digital Diplomacy To Manage State Repute In Crisis: A study of UAE during covid health crisis(Saudi Digital Library, 2025) Almuhaini, Latifah Saad; Hostein, AmandineBeing part of public diplomacy, digital diplomacy provides a tool to the states to reach world public beyond the borders and propel the state image not only in settled times, but during crisis to manage the situation and protect their reputation. Using the case of UAE, the dissertation aims to examine key characteristics of effective digital diplomacy that shape state’s reputation in a health crisis. UAE was able to present itself as a state capable enough to make quick decisions and innovate, using its official channels and embassies to provide a consist narrative about its reputational management. The Crisis and Emergency Risk Communication (CERC) frame provides a lens through which state’s crisis communication can be evaluated. On the basis of analysis done in this research, nine characteristics of effective digital diplomatic communication are identified as these were present in UAE’s case study of digital diplomacy during global health crisis COVID-19.4 0Item Restricted APPLICATION OF RISK MANAGEMENT FRAMEWORK IN RAILWAY PROJECTS: A SYSTEMATIC STUDY(Abdulaziz Alradhi, 2025) Alradhi, Abdulaziz; Dadashzadeh, BehnamThis dissertation investigates the application of risk management frameworks in railway projects through a systematic study of studies published between 2015 and 2025. The research critically examines how structured frameworks such as ISO 31000, and Enterprise Risk Management (ERM) have been implemented, the analytical tools used to operationalise them, and the challenges influencing their effectiveness. peer-reviewed studies and credible industry reports were analysed using a thematic synthesis approach. The findings reveal that ISO 31000 remains the most widely adopted framework, valued for its flexibility and governance alignment. It is frequently integrated with probabilistic and data-driven tools such as Bayesian Networks, Fuzzy Logic, and Multi- Criteria Decision-Making (MCDM) to enhance the quantitative precision of risk assessment. The research further highlights that the success of risk management depends not only on technical tools but also on leadership commitment, communication, and training. Projects that combined structured frameworks with digital integration and sustainability principles achieved greater resilience and transparency. This study contributes to the academic understanding of risk management in complex infrastructure. The dissertation concludes that effective risk management in railway projects requires a balanced integration of robust frameworks, advanced analytical tools, and strong organisational culture to ensure sustainable and reliable project outcomes.6 0