Saudi Cultural Missions Theses & Dissertations
Permanent URI for this communityhttps://drepo.sdl.edu.sa/handle/20.500.14154/10
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Item Restricted Understanding and Predicting the Behavioural Evolution of Promotional Spambots on Social Media(University of Birmingham, 2025-05-15) Alzahrani, Ohoud; Hendleym BobSocial media bots are rapidly evolving, rendering traditional detection tools increasingly ineffective as these bots adapt their strategies. This research introduces a dynamic and predictive framework for modelling the behavioural evolution of online promotional spambots. Inspired by biological DNA, bot activities are encoded into behavioural sequences, with each block capturing seven distinct post-level features. Techniques such as sequence alignment, cosine similarity, and hierarchical clustering are used to group bots into behaviourally similar “families.” These families serve as the foundation for identifying behavioural mutations—insertions, deletions, substitutions, and alterations—that signal adaptive strategy changes. The model evaluates how these mutations propagate within and across bot families and investigates their predictive power through mutation transfer analysis and an event-driven case study. Results show that bots within the same family are significantly more likely to share and adopt behavioural mutations than those from different families. Closely related bots achieved high precision and F1 scores (up to 0.97) in mutation transfer prediction. These findings support the feasibility of a behavioural evolution model as a scalable, interpretable, and adaptive tool for anticipating future bot activity and offering a proactive approach to combating evolving threats on social media platforms.13 0Item Restricted Comparative genomic analysis and evolutionary study of repetitive DNA for estimating variation and mobility(University of Leicester, 2024-09) Alwadani, Khawla; Heslop-Harrison, PatRepetitive DNA sequences, motifs repeated hundreds, thousands of times in the nuclear genome, represent typically half of the DNA and are some of the most rapidly evolving sequences. The objective of this study was to see how repetitive sequences differ and evolve between and within the wider Polygonaceae family and Malus domestica species. High volume DNA sequence reads from 12 Polygonaceae species were analysed using individual graphbased repeat clustering, revealing substantial differences in amount and composition of TEs. Many genus-specific repetitive elements were found in the comparative clustering of 21 samples, notwithstanding the close relationship of the genera. The repetitive sequence landscape was characterised among three apple cultivars. Repetitive DNA represents some 45 % of the apple genome. Graph-based sequence-read clustering showed the amount and genome composition of TEs with genome-wide dispersal was similar in various apple cultivars. LTR-retrotransposons were the most abundant, and similar Ty1-copia and Ty3-gypsy proportions. Analysis of in situ hybridisation to chromosomes was used for localisation of the various repetitive elements (including the 5S and 45S rDNA loci) and comparing abundance and organisation with published genome assemblies and unassembled raw sequence reads. In apple fruit, sectors of different colours are occasionally observed, just in the skin (peel) of the apple. The colour sectors arise from movement of TEs around the MYB transcription factor, giving rise to different expression of anthocyanin genes and hence pigmentation. Genomic DNA (c. 12-fold genome coverage) from the skin sectors was analysed. Notably, Gala is heterozygous for a key MYB gene. Insertional polymorphisms were identified in or around the MYB genes between the sectors and rest of the fruit, showing that DNA sequence movement was likely to cause the colour differences.49 0