Heddar Y, Fourar Y-O, Djebabra M.
Modelling herd behaviour in traffic jams using Markov chains-based reinforcement learning. International Journal of Simulation and Process Modelling [Internet]. 2026;23 (2) :119-133.
Publisher's VersionAbstractTraffic congestion remains a persistent problem that compromises road safety. This phenomenon is often amplified by driver behaviors, particularly those characterized by the herd effect. This study aims to model the emergence and dynamics of the herd effect in traffic jams and to simulate a strategy for mitigating this behavior among drivers. To achieve these objectives, reinforcement learning (RL) was employed within the frameworks of memoryless Markov chains and multi-phase Markov chains. The results demonstrate the effectiveness of Markov chains in accurately modeling the collective behavior of specific drivers. Likewise, the simulations illustrate RL’s capacity to regulate the herd effect and optimize individual decision-making during congestion. The findings suggest that traffic authorities may consider implementing RL-based strategies to mitigate herd behavior, improve traffic flow, and enhance road safety.
Chati M, Zerrouki H, Djebabra M, Chettouh S.
Dynamic Risk Assessment of Furnace System Using Dynamic Bayesian Networks. Quality and Reliability Engineering International [Internet]. 2026;42 (3) :1231–1249.
Publisher's VersionAbstractPreventing major accidents remains a critical priority in the process industry, given their potentially catastrophic consequences. However, the rare, stochastic, and dynamic nature of such accidents presents significant challenges for conventional risk assessment approaches. This study develops a novel dynamic risk assessment framework that addresses these challenges. The proposed methodology combines Bow-Tie analysis (BT) with Dynamic Bayesian Networks (DBNs) to create a robust decision- support tool for managing major industrial risks. Initially, the BT approach identifies basic events, safety barriers, and potential consequences across multiple equipment operating states. These elements are then systematically integrated into a DBN model, which provides enhanced flexibility in modeling the dynamic failure mechanisms of both basic events and safety barriers through continuous precursor integration. The framework’s effectiveness is demonstrated through a practical application examining a furnace system in a gas treatment unit at Hassi R’mel, Algeria. This case study validates the model’s capability to provide real-time risk assessment updates, offering significant improvements over static risk evaluation methods for industrial safety management.
Chati M, Hadef H, Djebabra M, Chettouh S.
Proposal for a New Hybrid Explosive Atmosphere(ATEX) Risk Assessment Approach Using RiskPriority Number and Analytical Hierarchy ProcessMethod. Nuclear Technology [Internet]. 2026;212 (4) :1050–1067.
Publisher's VersionAbstractThis study aims to highlight the importance of evaluating explosive atmosphere (ATEX) risks and to
propose a novel, more accurate and comprehensive risk assessment method compared to traditional existing
approaches. To address the limitations of traditional ATEX risk assessment methods, this study introduces a new
approach based on three key parameters: occurrence, detection, and severity. These factors are combined using
a weighted sum (WS) formula to calculate a modified risk priority number (RPN), enhanced by the analytic
hierarchy process.
This hybrid methodology provides a more precise and reliable assessment of ATEX risks. Moreover, the
findings of the proposed WS-RPN method (and its ATEX-specific version, WS-RATEX) demonstrate superior
accuracy and lower duplication rates compared to conventional risk assessment techniques. A sensitivity
analysis confirms the robustness, stability, and reliability of this approach, making it a valuable tool for
quantifying ATEX risks.
It is evident to say that WS-RPN represents a significant advancement in ATEX risk assessments. By
integrating a refined calculation model, and factoring in occurrence, detection, and severity, the latter ensures
a more systematic and reliable evaluation. Thus, with improved risk prioritization, this approach not only enhances
industrial installations’ safety but also serves as a more effective alternative to traditional assessment methods.