4.8LGApr 12
Exact Finite-Sample Variance Decomposition of Subagging: A Spectral Filtering PerspectiveYe Su, Mingrui Ye, Yining Wang et al.
Standard resampling ratios (e.g., $α\approx 0.632$) are widely used as default baselines in ensemble learning for three decades. However, how these ratios interact with a base learner's intrinsic functional complexity in finite samples lacks a exact mathematical characterization. We leverage the Hoeffding-ANOVA decomposition to derive the first exact, finite-sample variance decomposition for subagging, applicable to any symmetric base learner without requiring asymptotic limits or smoothness assumptions. We establish that subagging operates as a deterministic low-pass spectral filter: it preserves low-order structural signals while attenuating $c$-th order interaction variance by a geometric factor approaching $α^c$. This decoupling reveals why default baselines often under-regularize high-capacity interpolators, which instead require smaller $α$ to exponentially suppress spurious high-order noise. To operationalize these insights, we propose a complexity-guided adaptive subsampling algorithm, empirically demonstrating that dynamically calibrating $α$ to the learner's complexity spectrum consistently improves generalization over static baselines.
6.2CVMay 27, 2025
Spectral Compression Transformer with Line Pose Graph for Monocular 3D Human Pose EstimationZenghao Zheng, Lianping Yang, Hegui Zhu et al.
Transformer-based 3D human pose estimation methods suffer from high computational costs due to the quadratic complexity of self-attention with respect to sequence length. Additionally, pose sequences often contain significant redundancy between frames. However, recent methods typically fail to improve model capacity while effectively eliminating sequence redundancy. In this work, we introduce the Spectral Compression Transformer (SCT) to reduce sequence length and accelerate computation. The SCT encoder treats hidden features between blocks as Temporal Feature Signals (TFS) and applies the Discrete Cosine Transform, a Fourier transform-based technique, to determine the spectral components to be retained. By filtering out certain high-frequency noise components, SCT compresses the sequence length and reduces redundancy. To further enrich the input sequence with prior structural information, we propose the Line Pose Graph (LPG) based on line graph theory. The LPG generates skeletal position information that complements the input 2D joint positions, thereby improving the model's performance. Finally, we design a dual-stream network architecture to effectively model spatial joint relationships and the compressed motion trajectory within the pose sequence. Extensive experiments on two benchmark datasets (i.e., Human3.6M and MPI-INF-3DHP) demonstrate that our model achieves state-of-the-art performance with improved computational efficiency. For example, on the Human3.6M dataset, our method achieves an MPJPE of 37.7mm while maintaining a low computational cost. Furthermore, we perform ablation studies on each module to assess its effectiveness. The code and models will be released.