Abstract: Rules acquisiwn was studied in a type of decision systems where its values of condition attributes took domi- nance crisp values and those of decision attribute were intuitionistic fuzzy numbers. Firstly, the dominanting and domi- named classes of objects in the universe of discourse were constructed by the dominance crisp values of condition attri butes. Secondly,the lower/upper approximation set of an object were ascertanied by comparing the intuisionistic fuzzy numbers of decision attributes among objects. Thirdly, using discernibility matrix, the lower approximtion reduction and rules extraction algorithm based on discernibility relations among objects were devised. Finally,the presented model and algorithm were applied to performance audit for IT project,and some logical rules of performance audit for IT projects were obtiancd.

Key words: Dominanccintuitionistic fuzzy decision systems, Rough sets, Reduction, Performance audit for IT project