Solving Problems with Incomplete Information: A Grey Systems Approach

Publisher Summary This chapter discusses the fundamentals of grey systems theory by focusing on grey numbers, their arithmetic operations, and the degree and information content of grayness. A grey number is such a number whose exact value is unknown, but a range within which the value lies is known. In the study of grey systems, it is through various organizations of raw data for the researcher to sort out development or governing laws. This is a path of determining realistic governing laws from the available data. This path is called “generations of grey sequence.” Even though objective systems phenomena can be complicated and related data chaotic, they always represent the underlying governing laws. The key is for the researcher to uncover these laws and to make use of them by using appropriate methods. When collecting data, often because of some unconquerable difficulties, there appear some blanks in the data sequence collected. There also exist such data sequences that even though the data is complete some abnormal values are included because of the dramatic behavioral changes of the system under investigation.