arXiv:2606.16923cs.AIstat.ML2026-06

用侧信道信息修正模拟偏差,无需真实参数即可提升推断精度

MA-SBI: Misspecification-Aware Simulation-Based Inference via Side-Channel Guidance

论文配图:MA-SBI: Misspecification-Aware Simulation-Based Inference via Side-Channel Guidance
图 1 · 摘自论文原文
  • 利用文本等侧信道信息学习观测空间偏移,修正模拟误差
  • 仅用文本即达最优后验性能,在10次随机种子上稳定匹配理想结果
  • 适用于无真实参数标签的复杂系统推断,如疫情与认知科学数据

基于模拟的隐变量推断常受模拟器误设影响,即模拟与真实观测间的不匹配。现有最优方法RoPE通过真实参数校准对之间的最优传输来缓解,但此类配对在实际应用中通常不可得。而实践中常有非结构化侧信息,如状态标签、指令文本和政策公告。本文提出免校准的MA-SBI框架,将侧信道信息转化为后验修正信号。通过学习一个映射函数,将侧通道文本转换为观测空间的偏移量,作用于预训练的近似后验之前,无需重训练或真实参数。主定理证明,可实现的偏差降低受限于误设与侧信道间的互信息,且常数项在所有亚高斯噪声下成立(基于Donsker-Varadhan)。在hide-the-calibration基准测试中,仅使用文本的MA-SBI在10个种子和两种骨干网络上均达到与理想后验相当的表现(TOST等价),而罗佩在更多数据下仍不及。二者互补:当误设具有结构性且可从参数对恢复时,罗佩更优,符合理论预期。随机变体在真实新冠与OxCGRT流行病学数据上提升后验预测对数似然,并在良好设定的认知科学语料上保持后验不变。

原文摘要 · Abstract (English)

Simulation-based inference (SBI) of latent parameters is often hindered by simulator misspecification, the mismatch between simulated and real-world observations caused by inherent modeling simplifications. RoPE, the recent state-of-the-art for robust SBI, addresses this through optimal transport between learned representations of real and simulated observations, but requires ground-truth parameter calibration pairs that are typically unavailable in the very settings where SBI is needed. What practitioners do have is unstructured side-information such as regime labels, instruction text, and policy bulletins. We propose Misspecification-Aware Simulation-Based Inference (MA-SBI), a calibration-free framework that turns this side-channel into a posterior correction. A learned corrector maps side-channel text to an observation-space shift applied before any pre-trained amortized posterior, requiring no retraining and no parameter ground-truth. Our main theorem bounds achievable bias reduction by the mutual information between misspecification and side-channel, with a non-vacuous constant that extends to all sub-Gaussian noise via Donsker-Varadhan. On hide-the-calibration benchmarks, MA-SBI with text alone matches the oracle posterior across 10 seeds and two backbones (TOST equivalence), while RoPE given more data does not. The two approaches are complementary: where misspecification is structural and recoverable from parameter pairs, RoPE dominates, as the theory predicts. A stochastic variant improves posterior-predictive log-likelihood on real COVID and OxCGRT epidemiological data, and correctly leaves the posterior unchanged on a well-specified cognitive-science corpus.

模拟推断侧信道误差修正贝叶斯推断

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