A changepoint detector for modeling data received from at least one sensor in a process in the hydrocarbon industry. The data is segmented into a plurality of segments and for each segment a model is assigned and the data corresponding to the segment fit to that model. A plurality of segmentations are thus provided and these segmentations ar evaluated and assigned weights indicative of the fit of the models of the segmentation t the underlying data. The segmentation models are further used to calculate a result that may be input to a process control program.