Map representation of the time-delayed system in the presence of Delay   Time Modulation: an Application to the stability analysis
  We introduce the map representation of a time-delayed system in the presence of delay time modulation. Based on this representation, we find the method by which to analyze the stability of that kind of a system. We apply this method to a coupled chaotic system and discuss the results in comparison to the system with a fixed delay time. 
Won-Ho Kye, Muhan Choi, Tae-Yoon Kwon, Chil-Min Kim, and Young-Jai   Park