Self-Training the Neurochaos Learning Algorithm
Anusree M, Akhila Henry, Pramod P Nair
TL;DR
The paper tackles the challenge of learning with limited labeled data by introducing a hybrid semi-supervised framework that combines Neurochaos Learning (NL) with threshold-based Self-Training (ST). NL transforms inputs into chaos-based firing-rate features, while ST expands the labeled set using high-confidence pseudo-labels, mitigating noise and improving generalisation in low-data regimes. Evaluations on ten benchmark datasets across five classifiers show consistent macro-F1 gains, with particularly large improvements on nonlinear or imbalanced data such as Iris and Glass. The work demonstrates the effectiveness and robustness of chaos-inspired feature extraction paired with SSL, suggesting broad applicability to domains where labeling is expensive or scarce.
Abstract
In numerous practical applications, acquiring substantial quantities of labelled data is challenging and expensive, but unlabelled data is readily accessible. Conventional supervised learning methods frequently underperform in scenarios characterised by little labelled data or imbalanced datasets. This study introduces a hybrid semi-supervised learning (SSL) architecture that integrates Neurochaos Learning (NL) with a threshold-based Self-Training (ST) method to overcome this constraint. The NL architecture converts input characteristics into chaos-based ring-rate representations that encapsulate nonlinear relationships within the data, whereas ST progressively enlarges the labelled set utilising high-confidence pseudo-labelled samples. The model's performance is assessed using ten benchmark datasets and five machine learning classifiers, with 85% of the training data considered unlabelled and just 15% utilised as labelled data. The proposed Self-Training Neurochaos Learning (NL+ST) architecture consistently attains superior performance gain relative to standalone ST models, especially on limited, nonlinear and imbalanced datasets like Iris (188.66%), Wine (158.58%) and Glass Identification (110.48%). The results indicate that using chaos-based feature extraction with SSL improves generalisation, resilience, and classification accuracy in low-data contexts.
