Estimation of the control parameter from symbolic sequences: Unimodal   maps with variable critical point
  The work described in this paper can be interpreted as an application of the order patterns of symbolic dynamics when dealing with unimodal maps. Specifically, it is shown how Gray codes can be used to estimate the probability distribution functions (PDFs) of the order patterns of parametric unimodal maps. Furthermore, these PDFs depend on the value of the parameter, what eventually provides a handle to estimate the parameter value from symbolic sequences (in form of Gray codes), even when the critical point depends on the parameter. 
David Arroyo and Gonzalo Alvarez and Jos\'e Mar\'ia Amig\'o