Järpe, Eric2011-02-152011-02-152000-05-010349-8034http://hdl.handle.net/2077/24445Surveillance to detect changes of spatial patterns is of interest in many areas such as environmental control and regional analysis. A model which possesses both spatial and time dependence is the Markov chain Markov field. Here a special case of this, called the Ising dynamic model with zero external field, and change in its spatial interaction parameter is considered. A method for simulation exactly according to this Ising dynamic model, is proposed. Surveillance methods corresponding to common methods for the time independent case, are derived.15engMarkov chainMarkov fieldHeterogeneous external fieldZero external field perfect simulationon-line change detectionText