Bajada, Josef
Enhanced Smart Contract Reputability Analysis using Multimodal Data Fusion on Ethereum
Malik, Cyrus, Bajada, Josef, Ellul, Joshua
The evaluation of smart contract reputability is essential to foster trust in decentralized ecosystems. However, existing methods that rely solely on static code analysis or transactional data, offer limited insight into evolving trustworthiness. We propose a multimodal data fusion framework that integrates static code features with transactional data to enhance reputability prediction. Our framework initially focuses on static code analysis, utilizing GAN-augmented opcode embeddings to address class imbalance, achieving 97.67% accuracy and a recall of 0.942 in detecting illicit contracts, surpassing traditional oversampling methods. This forms the crux of a reputability-centric fusion strategy, where combining static and transactional data improves recall by 7.25% over single-source models, demonstrating robust performance across validation sets. By providing a holistic view of smart contract behaviour, our approach enhances the model's ability to assess reputability, identify fraudulent activities, and predict anomalous patterns. These capabilities contribute to more accurate reputability assessments, proactive risk mitigation, and enhanced blockchain security.
Identifying Likely-Reputable Blockchain Projects on Ethereum
Malik, Cyrus, Bajada, Josef, Ellul, Joshua
This raises the fundamental question of whether it is possible to systematically differentiate reputable projects from those that may not be. While existing research has primarily focused on detecting fraudulent activities--such as scams, Ponzi schemes, and network anomalies--these efforts remain centered on identifying and flagging illicit behavior rather than providing a holistic assessment of a project's overall reputability. Several studies have explored the detection of illicit activities on the Ethereum blockchain [8], the identification of Ponzi schemes [17], for anti-money laundering [15] and anomaly detection within the network [13]. While these contributions enhance our understanding of fraudulent behavior, they do not directly address the broader issue of evaluating whether a project itself is reputable. Given the growing number of Ethereum-based initiatives, the need for a systematic approach to assessing project reputability becomes increasingly evident. Distinguishing between legitimate and potentially deceptive ventures requires a dedicated methodology that extends beyond merely detecting illicit activity. By establishing such an approach, stakeholders, including investors, developers, and regulators can make more informed decisions, mitigate risks associated with unreliable projects, and foster a more secure and transparent investment landscape within the Ethereum ecosystem. This research aims to identify projects that are likely to be reputable by comparing them against a model comprised of data associated with a list of reputable projects from a source deemed to be trust-worthy. We therefore, define the following project aim to: develop a comprehensive methodology for identifying likely-reputable Ethereum Blockchain based projects using transactional data and machine learning techniques.
Autonomous Navigation of Tractor-Trailer Vehicles through Roundabout Intersections
Attard, Daniel, Bajada, Josef
In recent years, significant advancements have been made in the field of autonomous driving with the aim of increasing safety and efficiency. However, research that focuses on tractor-trailer vehicles is relatively sparse. Due to the physical characteristics and articulated joints, such vehicles require tailored models. While turning, the back wheels of the trailer turn at a tighter radius and the truck often has to deviate from the centre of the lane to accommodate this. Due to the lack of publicly available models, this work develops truck and trailer models using the high-fidelity simulation software CARLA, together with several roundabout scenarios, to establish a baseline dataset for benchmarks. Using a twin-q soft actor-critic algorithm, we train a quasi-end-to-end autonomous driving model which is able to achieve a 73% success rate on different roundabouts.
Efficient Temporal Piecewise-Linear Numeric Planning with Lazy Consistency Checking
Bajada, Josef, Fox, Maria, Long, Derek
State-of-the-art temporal planners that support continuous numeric effects typically interweave search with scheduling to ensure temporal consistency. If such effects are linear, this process often makes use of Linear Programming (LP) to model the relationship between temporal constraints and conditions on numeric fluents that are subject to duration-dependent effects. While very effective on benchmark domains, this approach does not scale well when solving real-world problems that require long plans. We propose a set of techniques that allow the planner to compute LP consistency checks lazily where possible, significantly reducing the computation time required, thus allowing the planner to solve larger problem instances within an acceptable time-frame. We also propose an algorithm to perform duration-dependent goal checking more selectively. Furthermore, we propose an LP formulation with a smaller footprint that removes linearity restrictions on discrete effects applied within segments of the plan where a numeric fluent is not duration dependent. The effectiveness of these techniques is demonstrated on domains that use a mix of discrete and continuous effects, which is typical of real-world planning problems. The resultant planner is not only more efficient, but outperforms most state-of-the-art temporal-numeric and hybrid planners, in terms of both coverage and scalability.
Temporal Planning with Semantic Attachment of Non-Linear Monotonic Continuous Behaviours
Bajada, Josef (King's College London) | Fox, Maria (King's College London) | Long, Derek (King's College London)
Non-linear continuous change is common in real-world problems, especially those that model physical systems. We present an algorithm which builds upon existent temporal planning techniques based on linear programming to approximate non-linear continuous monotonic functions. These are integrated through a semantic attachment mechanism, allowing external libraries or functions that are difficult to model in native PDDL to be evaluated during the planning process. A new planning system implementing this algorithm was developed and evaluated. Results show that the addition of this algorithm to the planning process can enable it to solve a broader set of planning problems.