Abstract Predictive Maintenance (PdM) emerges as a critical task of Industry 4.0, driving operational efficiency, minimizing downtime, and reducing maintenance costs. However, real-world industrial environments present unsolved challenges, especially in predicting simultaneous and correlated faults under evolving conditions. Traditional batch-based and deep learning approaches for simultaneous fault prediction often fall short due to their assumptions of static data distributions and high computational demands, making them unsuitable for dynamic, resource-constrained systems. In response, we propose OEMLHAT (Online Ensemble of Multi-Label Hoeffding Adaptive Trees), a novel model tailored for real-time, multi-label fault prediction in non-stationary industrial settings. OEMLHAT introduces a scalable online ensemble architecture that integrates online bagging, dynamic feature subspacing, and adaptive output weighting. This design allows it to efficiently handle concept drift, high-dimensional input spaces, and label sparsity, key bottlenecks in existing PdM solutions. Experimental results on three public multi-label PdM case studies demonstrate substantial improvements in predictive performance of OEMLHAT over previous batch-based and online proposals for multi-label classification, particularly with an average improvement in micro-averaged F1-score of 18.49% over the second most-accurate batch-based proposal and of 8.56% in the case of the second best online model. By addressing a critical gap in online multi-label learning for PdM, this work provides a robust and interpretable solution for next-generation industrial monitoring systems for fault detection, particularly for rare and concurrent failures. 
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                            How does combinatorial testing perform in the real world: an empirical study
                        
                    
    
            Studies have shown that combinatorial testing (CT) can be effective for detecting faults in software systems. By focusing on the interactions between different factors of a system, CT shows its potential for detecting faults, especially those that can be revealed only by the specific combinations of values of multiple factors (multi-factor faults). However, is CT practical enough to be applied in the industry? Can it be more effective than other industry-favored techniques? Are there any challenges when applying CT in practice? These research questions remain in the context of industrial settings. In this paper, we present an empirical study of CT on five industrial systems with real faults. The details of the input space model (ISM) construction, such as factor identification and value assignment, are included. We compared the faults detected by CT with those detected by the inhouse testing teams using other methods, and the results suggest that despite some challenges, CT is an effective technique to detect real faults, especially multi-factor faults, of software systems in industrial settings. Observations and lessons learned are provided to further improve the fault detection effectiveness and overcome various challenges. 
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                            - Award ID(s):
- 1822137
- PAR ID:
- 10194693
- Date Published:
- Journal Name:
- Empirical software engineering
- Volume:
- 25
- ISSN:
- 1382-3256
- Page Range / eLocation ID:
- 2661-2693
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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