distance areas 4722 are the same in this embodiment the number of axes status variables is two in the projected subspace when there are three axes as in fig1 however the variable name areas 4721 may be increased by one to carry out the processing in the same manner as described below the differential amount table 473 has several entries each consisting of a set of variable name areas 4731 differential amount areas 4732 and distance areas 4733 in the variable name areas 4731 of each entry are stored the names of status variables among w x y z that serve as axes among x 1 x n of a candidate of projectioned subspace in the differential amount areas 4732 are stored the observed values of status variables for the projected figure of the candidate for a subspace of the display shown by the variable name areas 4731 and the values of status variables obtained one observation period before in the distance areas 4733 are stored the values of the shortest distances from the observed values of status variables to the border 3 of the critical region 4 in the projected figure the data of the entries are stored in decreasing order of values of the differential amount areas 4732 or in the increasing order of values of the distance areas 4733 from the left in fig3 when the values of the differential amount areas 4732 are the same example values have been entered into the observation vale table according to the values shown in fig1 g that shows the left hand two combinations and assuming for purposes of illustration that the values for combination wx of fig1 h has moved to the.