Saudi Cultural Missions Theses & Dissertations
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Item Restricted Analysing and Visualising (Cyber)crime data using Structured Occurrence Nets and Natural Language Processing(Newcastle University, 2025-03-01) Alshammari, Tuwailaa; Koutny, MaciejStructured Occurrence Nets (SONs) are a Petri net-based formalism designed to represent the behaviour of complex evolving systems, capturing concurrent events and interactions between subsystems. Recently, the modelling and visualisation of crime and cybercrime investigations have gained increasing interest. In particular, SONs have proven to be versatile tools for modelling and visualising various applications, including crime and cybercrime. This thesis presents two contributions aimed at making SON-based techniques suitable for real-life applications. The main contribution is motivated by the fact that manually developing SON models from unstructured text can be time-consuming, as it requires extensive reading, comprehension, and model construction. This thesis aims to develop a methodology for the formal representation of unstructured textual resources in English. This involves experimenting, mapping, and deriving relationships between natural and formal languages, specifically using SON for crime modelling and visualisation as an application. The second contribution addresses the scalability of SON-based representations for cybercrime analysis. It provides a novel approach in which acyclic nets have been extended with coloured features to enable reduction of net size to help in visualisation. While the two contributions address distinct challenges, they are unified by their use of SONs as a formalism to model complex systems. Structured occurrence nets demonstrated their adaptability in representing both crime scenarios and cybercrime activities.39 0Item Restricted Analysing and Visualising (Cyber)crime data using Structured Occurrence Nets and Natural Language Processing(2025) Tuwailaa Alshammari; Professor Maciej KoutnyStructured Occurrence Nets (SONs) are a Petri net-based formalism designed to represent the behaviour of complex evolving systems, capturing concurrent events and interactions between subsystems. Recently, the modelling and visualisation of crime and cybercrime investigations have gained increasing interest. In particular, SONs have proven to be versatile tools for modelling and visualising various applications, including crime and cybercrime. This thesis presents two contributions aimed at making SON-based techniques suitable for real-life applications. The main contribution is motivated by the fact that manually developing SON models from unstructured text can be time-consuming, as it requires extensive reading, comprehension, and model construction. This thesis aims to develop a methodology for the formal representation of unstructured textual resources in English. This involves experimenting, mapping, and deriving relationships between natural and formal languages, specifically using SON for crime modelling and visualisation as an application. The second contribution addresses the scalability of SON-based representations for cybercrime analysis. It provides a novel approach in which acyclic nets have been extended with coloured features to enable reduction of net size to help in visualisation. While the two contributions address distinct challenges, they are unified by their use of SONs as a formalism to model complex systems. Structured occurrence nets demonstrated their adaptability in representing both crime scenarios and cybercrime activities.52 0Item Restricted Probabilistic Communication Structured Acyclic Nets(Newcastle University, 2024-04-16) Almutairi, Nadiyah; Koutny, MaciejAs the real world is full of uncertainty, we often estimate, or even guess to quantify uncertainty. Probabilistic models are the key to cope with uncertainty. One of the most prominent concurrent probabilistic models are probabilistic Petri nets. Petri nets are one of the mathematical modeling languages for the representation of distributed systems. They have been characterised as one of the expressive models to capture the notion of concurrency. Developing probabilistic concurrent system has been proved to be a difficult and ongoing problem. This is because in a concurrent systems different executions of a concurrent computation should have the same probability. However, this is not always guaranteed as concurrent systems may exhibit confusion. Confusion is an overlapping between conflict and concurrency – two fundamental concepts used in the area of concurrent systems modelling – which interferes with probability analysis. In this thesis, we set out to develop a probabilistic framework and outline approaches leading to a model where distributed choices are resolved in a way which allows one to carry out probabilistic estimation. In particular, the concept of cluster-acyclic net is introduced to transform a net with confusion into another net whose structure is free-choice which facilitates probabilistic estimation. Moreover, we formally extend calculating probabilities and the definition of conflict and confusion to Communication Structured Acyclic Nets (CSA-nets). Intuitively, in CSA-nets, acyclic nets are integrated into one structure that allows them to interact by the means of asynchronous and synchronous communications. CSA-nets are sets of interacting acyclic nets derived from Structured Occurrence Nets (SO-nets), which are a Petri net based formalism for representing the behaviour of complex evolving systems. We show that a CSA-net with confusion can be translated into another, confusion-free net, whose behaviour is closely linked to the behaviour of the original CSA-net. Also, a boolean satisfiability model is introduced to formally verify behavioural properties of CSA-nets.18 0