用核嵌入优化概率预测融合,提升风速预报精度。
Efficient pooling of predictions via kernel embeddings
- 将预测嵌入核空间,实现高效凸优化权重分配。
- 在风速预测中,新方法比传统线性融合提升显著。
- 适合需要高精度不确定性建模的决策场景。
概率预测是针对可能结果集的概率分布,能量化结果的不确定性,对有效决策至关重要。通过融合多个预测,可汇集信息源,通常得到更优的预测结果。现有方法多采用线性融合个体预测分布,可通过历史表现估计权重,使更准确的预测获得更高权重。本研究将预测嵌入再生核希尔伯特空间(RKHS),证明基于核评分规则优化线性池化权重为凸二次规划问题,可在任意结果域上高效实现最优融合。该方法还可推广至其他组合策略,并提出一种克服线性池理论局限的灵活泛化形式,在RKHS框架内仍保持高效。在实际风速预测应用中,该泛化方法显著优于传统线性池。
原文摘要 · Abstract (English)
Probabilistic predictions are probability distributions over the set of possible outcomes. Such predictions quantify the uncertainty in the outcome, making them essential for effective decision making. By combining multiple predictions, the information sources used to generate the predictions are pooled, often resulting in a more informative forecast. Probabilistic predictions are typically combined by linearly pooling the individual predictive distributions; this encompasses several ensemble learning techniques, for example. The weights assigned to each prediction can be estimated based on their past performance, allowing more accurate predictions to receive a higher weight. This can be achieved by finding the weights that optimise a proper scoring rule over some training data. By embedding predictions into a Reproducing Kernel Hilbert Space (RKHS), we illustrate that estimating the linear pool weights that optimise kernel-based scoring rules is a convex quadratic optimisation problem. This permits an efficient implementation of the linear pool when optimally combining predictions on arbitrary outcome domains. This result also holds for other combination strategies, and we additionally study a flexible generalisation of the linear pool that overcomes some of its theoretical limitations, whilst allowing an efficient implementation within the RKHS framework. These approaches are compared in an application to operational wind speed forecasts, where this generalisation is found to offer substantial improvements upon the traditional linear pool.
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