Retraction Note to: Soft Computing (2021) 25:12521–12536

The Editor-in-Chief and the Publisher have retracted this article. This article was submitted to be part of a guest-edited issue. An investigation concluded that the editorial process of this guest-edited issue was compromised by a third party and that the peer-review process has been manipulated. Based on the investigation's findings, the Editor-in-Chief therefore no longer has confidence in the results and conclusions of this article. Li Yang has not responded to correspondence from the Publisher about this retraction. The Publisher has not been able to obtain a current email address for Wang Ting.