Optimal incremental learning under covariate shift

Learning strategies under covariate shift have recently been widely discussed. The density of learning inputs under covariate shift is different from that of test inputs. Learning machines in such environments need to employ special learning strategies to acquire greater capabilities of generalizing through learning. However, incremental learning methods are also used for learning in non-stationary learning environments, which represent a kind of covariate shift. However, the relation between covariate-shift environments and incremental-learning environments has not been adequately discussed. This paper focuses on the covariate shift in incremental-learning environments and our re-construction of a suitable incremental-learning method. Then, the model-selection criterion is also derived, which is to be an essential object function for memetic algorithms to solve these kinds of learning problems.