الباحثون

Yizhou Sun

المنشورات 5

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Component and Dimension Sparsity in Transformer Refusal Mechanisms

Activation steering manipulates large language model behavior by intervening on internal activations, but the mechanistic basis of these interventions remains poorly understood. We decompose refusal steering into component-level interventions across four open-weight models, identifying the sparse subsets of attention a …

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Improving Function Space Flow Matching with Kernel Optimal Transport

Generative models for function-valued data, such as time series and solutions of partial differential equations, must learn distributions over infinite-dimensional spaces. Functional Flow Matching (FFM) extends Flow Matching to this setting, learning a velocity field whose flow transports a Gaussian prior to the data d …

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Graph Anomaly Detection as Finite-Horizon Control: Training-Free Scoring via Empirical Bayes

Fred Xu, Thomas Markovich, Florence Regol وآخرون · 2026

Node-level graph anomaly detection (GAD) identifies nodes whose attributes and interactions deviate from dominant graph regularities. Existing GAD models encode normality and anomaly scoring indirectly through architectures, message passing, reconstruction or contrastive objectives, and tuned score families. This entan …

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A Unified Uncertainty Representation for Graph Neural Networks via Doubly-Spectral Stochastic Expansion

Fred Xu, Thomas Markovich, Florence Regol وآخرون · 2026

Reliable deployment of graph neural networks requires calibration, out-of-distribution (OOD) detection, and robustness to distribution shift, yet existing methods address these needs with separate models and objectives. We model uncertain node embeddings as random graph signals: graph Fourier filters capture structural …

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