Zhang, Daowen; Lin, Xihong; Sowers, MaryFran R. - 2000
We consider Semiparametric regression for periodic longitudinal data. Parametric fixed effects are used to model the … covariate effects and a periodic nonparametric smooth function is used to model the time effect. The within–subject correlation … is modeled using subject-specific random effects and a random stochastic process with a periodic variance function. We …