and sd 3 u2032 u2033 measure water levels within river r 3 as shown in fig1 for example the rising of the water level at first sensor sd 3 u2032 will result in a rising of the water level at the second sensor sd 3 u2033 after a known period of time has elapsed which will result in a rising of the water level at the third sensor sd 3 u2032 u2033 after another known period of time has elapsed in an event of sensor failure the knowledge of regularities in mutual sensor dependencies is used to predict correct data for the failed sensor without relying on sensor duplication u2014 two sensors for sensing an exact same parameter at an approximately same location and time referring to fig2 an example of an event that modifies the regular flow of river r 3 is shown the second sensor sd 3 u2033 does not indicate a risen water level whereas the third downstream sensor sd 3 u2032 u2033 does then it is evident that either the second sensor was bypassed u2014 another branch bp of the river exists between the first sensor sd 3 u2032 and the third sensor sd 3 u2032 u2033 u2014 or that the second sensor sd 3 u2033 is failed though this example is very simple a correlation processor in the form.