https://bergstrom.org/tags/gradient-boosting/Gradient Boosting - Tag - Jorgen BergstromHugo -- gohugo.ioen-usJorgen BergstromFri, 06 Nov 2026 00:00:00 -0500https://bergstrom.org/posts/polymer_curve_classifier_comparison/Fri, 06 Nov 2026 00:00:00 -0500Jorgen Bergstromhttps://bergstrom.org/posts/polymer_curve_classifier_comparison/Introduction In an earlier article I trained a small CNN to decide whether an axis-free stress-strain image came from a rubber or a thermoplastic. The headline number was about 98% validation accuracy. I also added a caveat: because many materials had several curves — different strain rates, loading directions, or cyclic tests — curves from the same material could end up in both the training and validation sets. That kind of leakage makes a model look better than it really is.