Saudi Cultural Missions Theses & Dissertations
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Item Restricted Improvements of Technical Blockchain to Combat Ransomware Attacks in Healthcare(Newcastle University, 2024) Albalawi, Sarah; Mace, JohnIn the face of increasing cybersecurity threats, ransomware attacks have become a significant risk to critical sectors such as healthcare. As medical healthcare systems increasingly rely on electronic health records, they face heightened vulnerabilities that can compromise patient data and disrupt essential medical services. Ransomware attacks can encrypt and render critical medical records inaccessible, jeopardising patient care. This research aims to develop and evaluate a blockchain-based solution designed to secure medical healthcare records against ransomware, enhancing data integrity, availability, and security in healthcare systems. By leveraging blockchain technology, specifically by using smart contracts and decentralised applications on the Ethereum platform, the proposed solution creates a decentralised, immutable medical record management system. The system's robustness is demonstrated through a Python-based ransomware simulation, which compares locally stored medical data with data managed via blockchain. The findings show that the blockchain-based approach and smart contracts maintain data integrity and availability during ransomware attacks, preventing unauthorised access and ensuring continuous healthcare operations. These results suggest that adopting blockchain technology in healthcare can significantly mitigate the risks posed by ransomware, reduce operational disruptions, and protect patient data from evolving cyber threats, ultimately providing a scalable and secure solution for enhancing cybersecurity in the healthcare sector.20 0Item Restricted Investigation of Inorganic Photocatalytic Systems(Queen’s University Belfast, 2024-11) Alofi, Saleh; Mills, AndrewThis thesis details the improvement of our current understanding of the photocatalytic process through a series of detailed studies of the SA removal by a variety of different photocatalytic films. Chapter 1 and 2 provide an introduction to the subject and experimental techniques commonly employed. The first result, Chapter 3 revisits two kinetic models used to explain the photocatalytic oxidation of stearic acid (SA) by O₂, a process commonly used to assess the activity of new materials for self-cleaning. The first model, based on zero-order kinetics, describes a SA layer on top of a photocatalyst, An important, but rarely noted feature of this system is that the rate of SA removal depends directly upon the fraction of absorbed ultra-bandgap radiation, which suggests that the photocatalyst particles are extensively networked, thereby allowing the photogenerated electrons and holes to move rapidly and efficiently to the surface to effect the destruction of SA. The second model, explaining first-order kinetics, applies to mesoporous films where SA is within the photocatalytic film. It is shown that, contrary to previous reports, this model is not appropriate for porous photocatalytic films in which the particles are extensively networked, such as ones based on powders or sol–gel films, even though they too may exhibit decay kinetics where the order is > 0. The reason for the latter kinetics appears to be a distribution of reactivities through such films, i.e. high and low activity sites. The second result chapter, Chapter 4 discusses the efficiency of electron and hole transport (EHT) in TiO₂ films during the photocatalytic oxidation of stearic acid (SA) by ambient air. The EHT model is rigorously tested on highly absorbent TiO₂ films, with absorbance values much greater than 2. These films include mesoporous (sol-gel) and microporous (P25 TiO₂) types, approximately 0.5–1 μm thick, coated with a layer of (SA). Each film produced identical [SA] vs irradiation time decay profiles when irradiated from the front or the back. These results suggest that the transport of the photogenerated holes, and most likely electrons too, in these films is very efficient. When the SA layer is replaced with an Ag photocatalyst indicator ink, Ag paii, on a P25 TiO₂ film, and irradiated from the back, the ink changes colour quickly due to the reduction of Ag+ in the ink, indicating that the transport of photogenerated electrons through the film is also efficient. The third result, Chapter 5 The kinetics of stearic acid, SA, removal by photocatalytic films are modelled using a log-normal distribution in surface reactivity, which shows that as the distribution in reactivity, ρ, increases, so too does the apparent order of reaction, m, of the observed variation in SA concentration, [SA], versus irradiation time, t. The model is used to fit the observed [SA] vs. t profiles exhibited by three very different TiO₂ films, namely Activ™ self-cleaning glass, and prepared sol-gel TiO₂ and P25 TiO₂ films. These films show decay kinetics, with m = 0.3, 0.44 and 0.6, respectively, which fit the model predicted decay profiles with distribution width, ρ, values, 0.4, 0.54 and 0.7, respectively. Finally, the fourth result Chapter 6 The kinetics of the removal of stearic acid (SA) islands by photocatalytic coatings is controversial, with some reporting that the islands fade as their thickness, h, decreases with the irradiation time, t, but maintain a constant area, and others reporting that., the islands shrink, rather than fade. This study attempts to understand the possible cause for these two very different observations through a study of the destruction of a cylindrical SA island and an array of such islands, on two different photocatalytic films. It is shown that, irrespective of whether there is a single cylindrical island or an array of islands, h decreases uniformly with t, −dh/dt = constant, and −da/dt = 0, so that the SA islands just fade. However, in a study of the photocatalyzed removal of SA islands with a volcano-shaped profile, rather than that of a cylinder, it is found that the islands shrink and fade. A simple 2D kinetic model is used to rationalize the results reported in this work.26 0Item Restricted PATIENT’S VIEWS ON ACCESS TO DENTAL CARE: A SERVICE EVALUATION TO INFORM HEALTH SYSTEMS STRENGTHENING AT KING'S COLLEGE DENTAL HOSPITAL(King's College London, 2024-08) Alblayhd, Maysam; Gallagher, JenniferAim: To explore the views of patients who attend King’s College Dental Hospital on the current hospital service and accessibility to hospital dental services in Southeast London. Materials and Methods: A descriptive cross-sectional study was conducted on a consecutive sample of patients (including parents of patients) over 13 weeks (April-July 2024). The study used a validated self-administered questionnaire with five domains informed by the Penchansky and Thomas model of access. The first domain examined overall satisfaction, the second examined accessibility, the third domain was on the availability of services, the fourth investigated accommodation, and the fifth collected demographic information, and additional comments from the participants. The questionnaire was piloted and tested for content validity. This service evaluation study has been approved by the King's College Hospital NHS Foundation Trust audit and service evaluation team (Reference: DENT-M-01-23). Results: In total, 230 patients responded to the survey, of which 56% were female and 57% were adults (25-74 years old). The study found high overall satisfaction with the hospital’s services, with particular appreciation for staff and students professionalism and friendliness. However, issues related to accessibility, such as long travel times and inadequate physical infrastructure, were identified as areas needing improvement. While most patients reported satisfaction with the availability of services, concerns were noted regarding appointment scheduling and waiting times. Demographic analysis revealed variations in satisfaction levels across different groups, highlighting the need for targeted improvements in service delivery, especially regarding waiting time. Conclusion: The findings suggest that while King’s College Dental Hospital generally receives a high satisfaction rate. There are significant areas for enhancement, particularly in accessibility and accommodation. Addressing these issues could improve the overall quality of care. Future efforts should focus on reducing travel-related barriers, optimising appointment management, and addressing infrastructure concerns to better meet patient needs and expectations.23 0Item Restricted Moving Target Detection and Prediction towards Cyber Agile Cellular Networks(Alotaibi, Saad, 2019-04-29) Alotaibi, Saad; Song, HoubingAgile networks such as cellular networks are often prone to attacks emanating from various loopholes. The security loopholes increase the vulnerability of a network whereby the attackers are able to utilize the attack surface to execute an attack. One of the best approach of eliminating the security loopholes is to reduce the attack surface that in the network. An approach known as Moving Target Defense (MTD) is a robust mechanism aimed at reducing the attack surface in a cyber-agile network. This paper proposes the development of an MTD framework aimed at reducing the attack surface in a cloud- based network. The approach aims to formulate how multiple virtual machines can be migrated from one network layer to another with the aim of minimizing the chances of an attacker exploiting the network vulnerabilities. The proposed framework also addresses the mechanism of transforming the I.P addresses of the virtual machines after successful migration to the new network layer. The framework is simulated with the OpenStack platform whereby the network layer is implemented using nova- compute while the hardware is implemented using neuron framework. The algorithmic framework is further supported and implemented using Python programming platform. The experimental results indicate that the migration process is attained within a maximum duration of 0.3 seconds, which is adequate enough to prevent an attacker from executing an attack on the network. The proposed MTD framework is capable of improving the security of a cyber-agile network by minimizing the attack surface. For enhancing the security of the system, the IP mutation methodology has also been proposed along with MTD. For checking the efficiency of proposed IP mutation methodology, two metrics were defined i.e. assurance and avoidance. The results for IP mutation methodology suggested that it uses flexible and elastic characteristics of SDN and helps to enhance the security of the system.13 0