Hranisavljevic, Nemanja

This report summarizes the workshop on “Learning Approaches for Hybrid Dynamical Systems”, held at the 2025 Conference on Machine Learning for Cyber-Physical Systems (ML4CPS). The workshop aimed to strengthen collaboration and foster exchange between institutions engaged in research on model learning methods for hybrid CPSs. The participating research groups approach the topic from diverse perspectives, for example, from an application perspective, from a tool perspective, or from a fundamental and formal perspective. Accordingly, this paper synthesizes the discussions from the workshop and presents an overview of key perspectives on several central topics, including the taxonomy of hybrid systems, current learning paradigms and techniques, and particularly representative use cases.

A large palette of models and their corresponding learning algorithms have been applied to time series observed from cyber-physical systems (CPSs). For some use cases, simple linear methods are sufficient, while for others, even sophisticated machine learning approaches fail to extract subtle patterns in system behavior. To date, the literature has not examined this phenomenon adequately and lacks a comprehensive analysis linking the characteristics of CPSs with the suitability of different models and learning algorithms. In this work, after examining the complexity of multiple real-world and artificial CPS use cases, we identify several key aspects that distinguish them: 1) the number of system variables, 2) the degree of interdependence between discrete-event part and continuous part of the system, and 3) the number of unobserved system inputs. By analyzing the approaches successfully applied in the respective use cases, we were able to distill preferred techniques for addressing systems of different complexity levels.