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Zhiwu Xie

4 accepted papers

2026

Escaping Optimization Stagnation: Taking Steps Beyond Task Arithmetic via Difference Vectors

AAAI 2026technical

Current methods for editing pre-trained models face significant challenges, primarily high computational costs and limited scalability. Task arithmetic has recently emerged as a promising solution, using simple arithmetic operations—addition and negation—based on task vectors which are the differenc

Cited by 0SourcePDFScholar
2026

Fix the Loss, Not the Radius: Rethinking the Adversarial Perturbation of Sharpness-Aware Minimization

ICML 2026poster

Sharpness-Aware Minimization (SAM) improves generalization by minimizing the worst-case loss within a fixed parameter-space radius neighborhood. SAM and its variants mainly rely on a first-order linearized surrogate, while flat minima are inherently a second-order (curvature) notion. We revisit this…

Cited by 0SourceScholar
2026

Rethinking Loss Reweighting for Imbalance Learning as an Inverse Problem: A Neural Collapse Point of View

ICML 2026poster

Loss reweighting is a widely used strategy for long-tailed classification, but existing reweighting strategies often rely on heuristics and rarely define a well-specified target. Inspired by Neural Collapse (NC), the ideal simplex Equiangular Tight Frame (ETF) terminal geometry suggests equal per-cl…

Cited by 0SourceScholar
2026

Space Alignment Matters: The Missing Piece for Inducing Neural Collapse in Long-Tailed Learning

AAAI 2026technical

Recent studies on Neural Collapse (NC) reveal that, under class-balanced conditions, the class feature means and the classifier weights spontaneously align into a simplex equiangular tight frame (ETF). In long-tailed regimes, however, severe sample imbalance tends to prevent the emergence of the NC

Cited by 0SourcePDFScholar