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Table 2 Whitened functions for six grades

From: Application of fuzzy evaluation technique and grey clustering method for water quality assessment of the coastal and estuaries of selected rivers in Sarawak

Whitened function

Expression

Scope

 

1

(0 ≤ Ci ≤ CI)

f 1 (Ci)

(CII–Ci)/(CII–CI)

(CI < Ci < CII)

 

0

(Ci > CII)

 

(Ci–CI)/(CII–CI)

(CI < Ci < CII)

f 2 (Ci)

(CIII–Ci)/(CIII–CII)

(CII < Ci < CIII)

 

0

(Ci ≤ CI or Ci ≥   CIII)

 

(Ci–CII)/(CIII–CII)

(CII < Ci < CIII)

 

1

(Ci = CIII)

f 3 (Ci)

(CIV–Ci)/(CIV–CIII)

(CIII < Ci < CIV)

 

0

(Ci ≤ CII or Ci ≥  CIV)

 

(Ci–CIII)/(CIV–CIII)

(CIII < Ci < CIV)

 

1

(Ci = CIV)

f 4 (Ci)

(CV–Ci)/(CV–CIV)

(CIV < Ci < CV)

 

0

(Ci < CIII or Ci ≥  CV)

 

(Ci–CIV)/(CV–CIV)

(CIV < Ci < CV)

 

1

(Ci = CV)

f 5 (Ci)

(CVI–Ci)/(CVI–CV)

(CV < Ci < CVI)

 

0

(Ci ≤ CIV or Ci ≥  CVI)

 

0

(0 < Ci < CV)

f 6 (Ci)

(Ci–CVI)/(CVI–CV)

(CV < Ci < CVI)

 

1

(Ci > CVI)