RETRACTED: Direct adaptive control based on gradient estimation and industrial application

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the authors.This article contained elements of a previously published paper. No permission was sought and the original paper was neither referenced nor cited. The authors would like to apologize for this administrative error on their part.