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Yuma Ichikawa

6 accepted papers

2026

High-Dimensional Learning Dynamics of Quantized Models with Straight-Through Estimator

ICML 2026poster

Quantized neural network training optimizes a discrete, non-differentiable objective. The straight-through estimator (STE) enables backpropagation through surrogate gradients and is widely used. While previous studies have primarily focused on the properties of surrogate gradients and their converge…

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2026

Sign Lock-In: Randomly Initialized Weight Signs Persist and Bottleneck Sub-Bit Model Compression

ICML 2026poster

Sub-bit model compression seeks storage below one bit per weight, where the sign bit becomes a fixed-cost bottleneck as magnitudes are aggressively compressed. Across Transformers, CNNs, and MLPs, learned sign matrices resist low-rank compression and are spectrally indistinguishable from i.i.d. Rade…

Cited by 0Source ↗Scholar ↗
2024

Learning Dynamics in Linear VAE: Posterior Collapse Threshold, Superfluous Latent Space Pitfalls, and Speedup with KL Annealing

AISTATS 2024poster

Variational autoencoders (VAEs) face a notorious problem wherein the variational posterior often aligns closely with the prior, a phenomenon known as posterior collapse, which hinders the quality of representation learning. To mitigate this problem, an adjustable hyperparameter $\beta$ and a strateg…