Pls check one paper, A Probabilistic Approach to Determining Biological Structure:Integrating Uncertain Data Sources by Russ B. Altman Stanford University Medical Center Running Title: Computing Uncertain Biological Structures Keywords: probabilistic structure estimation, Kalman filter, molecular structure,simulated annealing, least squares, Bayesian estimation, non- Gaussian noise, protein,RNA. ftp://ftp.ksl.stanford.edu/pub/KSL_Reports/KSL-95-18.ps.gz or cache, http://webcache.googleusercontent.com/search?q=cache:64TZRIPcU4