arXiv Machine Learning

Learnable Spectral Activations

arXiv Machine Learning
Jun 30

Spectral Gating via Damped Oscillations for Adaptive Implicit Neural Representations

arXiv:2606. 23129v2 Announce Type: replace-cross Abstract: Implicit Neural Representations (INRs) have been proven successful in encoding continuous signals through coordinate-based networks, yet facing a spectral dilemma: periodic activations capture fine details but act as all-pass filters that memorise noise, while spatially compact activations regularise effectively but suffer from low-frequency bias.

By Alex Costanzino, Pierluigi Zama Ramirez, Giuseppe Lisanti, Luigi Di Stefano
arXiv Machine Learning
Aug 27

When Does Frequency Decomposition Benefit Physics-Informed Neural Networks? A Preliminary Ablation Study

The paper investigates when frequency decomposition aids Physics-Informed Neural Networks (PINNs) by introducing a dual‑branch, spectrally‑gated architecture (DBSG‑PINN) that separates low‑ and high‑frequency components. Experiments on five one‑dimensional PDE benchmarks show that frequency decomposition significantly reduces error—up to 59.2% on a multimodal wave problem—when the target solution is spectrally complex, but offers little improvement on smoother problems and can even worsen performance on a simple 1D wave benchmark. The adaptive gate’s effectiveness scales with the spectral richness of the solution, suggesting it exploits frequency structure rather than adding noise.

By Shubham Rai
arXiv AI
Sep 1

Frequency Selective Neural Networks as a Foundation Architecture for Time Series Learning

The paper introduces the Frequency Selective Neural Network (FSNN), a new foundation architecture for time‑series learning that embeds advanced signal‑processing mathematics into its neural topology. By using a fully differentiable Wiener‑like filter bank optimized with complex‑domain backpropagation, FSNN autonomously discovers and isolates the precise physical modes of a given task, thereby avoiding the spectral entanglement that plagues CNNs, RNNs, and Transformers. Extensive evaluations show that FSNN achieves state‑of‑the‑art predictive performance, attaining 77.0 % average accuracy on the 10 multivariate UEA datasets and leading all major metrics on the imbalanced PTB‑XL ECG benchmark, while converging directly on physically meaningful frequency bands such as the cardiac QRS complex.

By Hui Huang, Ye Sun, Shiyan Hu
arXiv Machine Learning
Sep 25

Spectral Graph Neural Networks with Hermite Polynomials: A Comprehensive Study

The paper introduces HermNet, a spectral graph neural network that uses Hermite polynomials for nodewise prediction and normalized propagation, avoiding eigendecomposition or learned bases. It compares HermNet to other complete polynomial bases, examining how coordinate choices affect optimization under limited training. Experiments on synthetic and real data show regimes where HermNet outperforms alternatives, and analyze the impact of calibration, regularization, and training duration on performance.

By Shuang Wu
arXiv Machine Learning
Oct 15

Resolution Allocation with Learnable Resizing and Spectral Filter Parameterization

The paper investigates how learnable downsampling and spectral-domain filter parameterizations interact in convolutional networks. By studying spatial and spectral kernels with learned resolution allocation via cropped resizing, the authors find that spectral kernels benefit more from increased resolution, achieving consistent accuracy gains across EuroSAT, CIFAR‑10, and STL‑10 for two model sizes. The advantage persists even when the total retained area is equalized, though its magnitude varies with model complexity and resizing implementation.

By Wei Wu, Eric C. Larson