# Recent Advances in Fault Diagnosis and Opacity Analysis in Discrete Event Systems

## TL;DR

This survey paper reviews recent developments in fault detection and privacy analysis in systems that change in discrete steps, focusing on modern challenges like communication issues and cyber threats.

## Contribution

The paper provides a structured overview of recent advances in diagnosability and opacity analysis for discrete event systems under modern challenges.

## Key findings

- Recent advances in diagnosability verification and enforcement across various DES models are surveyed.
- Contemporary results on opacity verification include complexity findings and robust formulations.
- Emerging themes and open problems in diagnosis and opacity for DESs are highlighted.

## Abstract

This paper continues the historical and technical trajectory of fault diagnosis and opacity analysis in discrete event systems (DESs). Whereas the previous work reviewed the foundational developments of event diagnosis and opacity, this survey focuses on recent advances over the past decade by addressing modern challenges such as communication losses, delays, distributed architectures, and cyber-attack scenarios. Specifically, we present a structured overview of diagnosability verification and enforcement across automata, Petri nets, and other DES models under these scenarios. In parallel, we review contemporary results on opacity verification and enforcement, including complexity findings, reduction techniques, and robust or attack-resilient formulations. In addition, this survey provides an updated picture of the evolving research landscape and highlights emerging themes and open problems in diagnosis and opacity for DESs.