Adaptive Ordinal Sample-Weighted Meta-ResNet for Fault Severity Classification Under Class Imbalance

In intelligent fault diagnosis, fault severity classification with class imbalance remains a tremendous challenge. To simultaneously consider relative natural order in fault severity and class imbalance, we propose the adaptive ordinal sample-weighted meta residual network (AOSW-MRN). The AOSW-MRN model uses a weighting network and a meta-model cloned from the residual network to create a nonlinear weighted mapping. It adaptively learns sample weights from a balanced and clean-label meta-dataset, training a model robust to imbalance and ordinal relationships. We validate its effectiveness in two real-world case studies with different imbalance rates. Experimental results demonstrate that our model outperforms several existing Start-of-the-Art models regardless of classification and regression performance since it considers the ordinality of samples in the feature space.