Evolving Gaussian process kernels from elementary mathematical expressions for time series extrapolation

[EN]Choosing the best kernel is crucial in many Machine Learning applications. Gaussian Processes are a state-of-the-art technique for regression and classification that heavily relies on a kernel function. However, in the Gaussian Processes literature, kernels have usually been either ad hoc design...

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Detalhes bibliográficos
Autores: Román Txopitea, Ibai, Santana Hermida, Roberto, Mendiburu Alberro, Alexander, Lozano Alonso, José Antonio
Formato: artículo
Fecha de publicación:2021
País:España
Recursos:Universidad del País Vasco
Repositorio:Addi. Archivo Digital para la Docencia y la Investigación
OAI Identifier:oai:addi.ehu.eus:10810/54393
Acesso em linha:http://hdl.handle.net/10810/54393
Access Level:acceso abierto
Palavra-chave:evolutionary search
Gaussian processes
genetic programming
kernel learning
time series extrapolation
Descrição
Resumo:[EN]Choosing the best kernel is crucial in many Machine Learning applications. Gaussian Processes are a state-of-the-art technique for regression and classification that heavily relies on a kernel function. However, in the Gaussian Processes literature, kernels have usually been either ad hoc designed, selected from a predefined set, or searched for in a space of compositions of kernels which have been defined a priori. In this paper, we propose a Genetic Programming algorithm that represents a kernel function as a tree of elementary mathematical expressions. By means of this representation, a wider set of kernels can be modeled, where potentially better solutions can be found, although new challenges also arise. The proposed algorithm is able to overcome these difficulties and find kernels that accurately model the characteristics of the data. This method has been tested in several real-world time series extrapolation problems, improving the state-of-the-art results while reducing the complexity of the kernels.