Sub-optimum evaluation on incomplete network information system

An information system is classified into two classes, namely complete information system and incomplete information system. A unified description has been proposed through the concrete analysis of information systems. And based on the conclusion, a new method of decision making has been presented. The theoretical basis of the method is non-optimum analysis theory (NOAT), and thereby the NOAT is further perfect by introduced the concepts of middle-optimum degree and unknown-optimum degree. Then the entropy of information systems is defined. Meanwhile, the concept of influence degree has also introduced. Finally, it discusses about three decision making principles, namely maximum influence degree principle, minimum risk principle and maximum risk principle. An example is included to illustrate three decision making principles.