Functional Grey Relational Model in Water Quality Assessment

The functional data analysis (FDA) theory is introduced into the conventional grey relational (GR) method to establish a functional grey relational (FGR) model. Compared with GR FGR has the following advantages: (1) the requirement for monitoring is much less, for example, missing values or different sampling times are acceptable; (2) the variation of water quality status can be represented more comprehensively and intuitively. In this paper the procedure of FGR is discussed and the water quality in the water source area of Jiangning waterworks is assessed as used as an illustration. The result shows that it belongs to classification "II" but was biased towards classification "III" from January to April.