Notice of retraction

IOS Press has retracted the following publication from its online content: [International Journal of Knowledge-based and Intelligent Engineering Systems, 23(4) (2019), 295–301] DOI: 10.3233/KES-190418

Model for evaluating the teaching effect of the college English public speaking course under the flipped classroom hybrid teaching mode with intuitionistic trapezoidal fuzzy numbersJing XuSchool of Foreign Languages, Shanxi Datong University, Datong, Shanxi 037009, China

The above article originally published in International Journal of Knowledge-based and Intelligent Engineering Systems volume 23, number 4, 2019, pp. 295–301 has been retracted in consultation between the Editor-in-Chief and the author. Upon inspection it was found that the article was published earlier under the same title and by the same author in Journal of Intelligent and Fuzzy Systems, volume 37, number 2, 2019, pp. 2051–2058 [DOI: 10.3233/JIFS-179268]. Because of this duplicate publication the journal has decided to retract the article from its online catalogue.