Covariance Function
Covariance functions are mathematical tools defining the relationships between data points in Gaussian process (GP) models, crucial for probabilistic predictions and uncertainty quantification. Current research emphasizes developing more flexible covariance functions to handle complex data structures, including non-stationary and sparsely correlated multi-output scenarios, often employing techniques like kernel convolutions and spike-and-slab priors within variational or expectation-maximization frameworks. These advancements improve the scalability and accuracy of GP models for diverse applications, such as time series analysis, system identification, and spatial modeling, while also enabling more efficient inference and interpretability through model reduction and the incorporation of prior knowledge.