The change point problem in a regression model is usually referred
to as segmented regression. In the profile applications,
multiple data sets are collected over time in a functional data
sampling framework. Mahmoud et al. [6] and Zou et al. [7] proposed
methods based on likelihood ratio statistics to estimate
the step change point in simple linear profiles in phases I and II,
respectively. Kazemzadeh et al. [11] used the same method to
estimate the change point in polynomial profiles under a step
shift in phase