Cyber-Physical Systems (CPS) drive modern critical infrastructures by tightly integrating physical processes with computation and communication networks. This convergence exposes CPS to sophisticated cyber threats propagating across physical, control, and network layers, where stealthy and multi-stage attacks manifest through weak and distributed signals, challenging centralized intrusion detection systems and monolithic AI models that struggle to scale across heterogeneous subsystems and lack the interpretability required in safety-critical environments. This paper proposes a hierarchical multi-agent AI framework for automated cybersecurity assessment with human-understandable explanations in networked CPS. The framework dynamically instantiates a task-specific agent hierarchy from a natural language description of the target system, aligning the security analysis process with the underlying CPS architecture. Specialized agents perform fine-grained analysis of heterogeneous data sources, subsystem supervisors aggregate and contextualize local findings, and a deliberative round-table consensus mechanism enables cross-subsystem correlation for detecting coordinated and stealthy attacks. The framework is evaluated using four LLMs (Qwen 3 4B, Qwen 3 8B, Llama 3.1 8B, and Llama 3.3 70B) across three datasets (PicoDomain, CERT r5.2, and SWaT), achieving perfect recall for models with 8B parameters and above (i.e., zero missed attacks), while reaching an accuracy of 90.18% on PicoDomain, 92.77% on CERT r5.2, and 96.97% on SWaT. An ablation study confirms the effectiveness of the cross-subsystem consensus mechanism, demonstrating substantial precision gains when collaborative deliberation is enabled. Overall, this work establishes hierarchical multi-agent architectures as a scalable, interpretable, and structure-aware foundation for AI-driven cybersecurity in networked CPS.

Abstract Smart cities, as a constantly evolving field, offer numerous opportunities for advancement and innovation. In particular, more and more specific sectors within smart cities currently require increased attention and development. Notably, the integration of emerging technologies holds promise for significant progress in efficiency and management across various urban issues, with urban waste management being a key focus of this research. In this paper, we propose a new methodology for intelligent waste management combining graph-based modeling and advanced machine learning techniques. A case study of a municipality in the Melbourne area (Australia) is examined, where smart bins equipped with fill-level sensors have been deployed, and their data made publicly accessible. The core of this investigation lies in utilizing sophisticated machine learning models, including Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU), for predicting bin fill levels. Additionally, we introduce a graph-based spatial representation in which bins are modeled as nodes of a weighted graph, and graph embedding techniques are employed to capture and encode spatial dependencies among them. The findings validate the effectiveness of the proposed methodology, achieving a Mean Absolute Error (MAE) of 0.16, a Root Mean Squared Error (RMSE) of 0.21, a Mean Squared Error (MSE) of 0.044, and an R 2 of 0.83, which outperforms the reference baseline. Our results highlight how the integration of spatial information through graph embedding holds promise for improving predictions in smart waste management. Furthermore, the study suggests a transferable methodological framework, applicable at the architectural level to smart city challenges where spatially distributed entities exhibit interdependent temporal dynamics, pending empirical validation across further domains and cities.

Deep learning, owing to its transformative influence across a myriad of sectors, has recently made its foray into the legal domain, instigated by the surge in digitization. Among the multitude of applications in this space, legal document classification emerges as a pivotal yet complex undertaking. Legal texts, characterized by unique domain-centric semantics and intricate linguistic patterns, necessitate precision-driven classification systems for numerous practical implications. This paper illuminates the challenges and opportunities in automating the classification of European Union (EU) legal documents, emphasizing the interrelationships among statutes and the hierarchical nature of legal references. In this context, we introduce a novel graph data modeling technique that adeptly marries content-centric indicators with the relational dynamics inherent among diverse legal documents. Central to our approach is a framework that melds text embeddings with graph neural networks for the classification of legal documents aligned with their subject-based directories. Empirical evaluations on the EU law dataset underline the efficacy of our model across varying granularities, from general thematic categories to intricate subtopics. This endeavor not only augments the comprehensibility and accessibility of EU jurisprudence but also holds significant implications across regulatory compliance, legal research, and policy formulation, underscoring the potential of deep learning in reshaping legal paradigms.