%                  FI.M
 %----------------------------------------------------------------
 %       Fuzzifiction Procedure
 %         FUZZY.M will use this function, FI.m
 %----------------------------------------------------------------
 
 function membership=fi(u)

 %----------------------------------------------------------------
 %   DEFINE THE RANGE OF THE FUZZY SETS
 %----------------------------------------------------------------
 
  up2=2/3;up1=1/3; un2=-2/3; un1=-1/3;
  
  %--------------------------------------------------------------
  %   Initialize the membership function
  %--------------------------------------------------------------
  
  pbu=0; pmu=0; psu=0; zeu=0;
  nbu=0; nmu=0;nsu=0;
  
  %-------------------------------------------------------------
  %   Fuzzification
  %------------------------------------------------------------
  
    if u >=1,pbu=1;
elseif u >=up2, pbu=(u-up2)/(1-up2); pmu=(1-u)/(1-up2);
elseif u >=up1, pmu=(u-up1)/(up2-up1); psu=(up2-u)/(up2-up1);
elseif u >=0, psu=u/up1;             zeu=1-u/up1;
elseif u >=un1, zeu=(un1-u)/un1;      nsu=u/un1;
elseif u >=un2, nsu=(u-un2)/(un1-un2); nmu=(un1-u)/(un1-un2);
elseif u >=-1, nmu=(1+u)/(1+un2);  nbu=(un2-u)/(1+un2);
  else      nbu=1;
  end;
  %---------------------------------
  %    Assign outputvector
  %---------------------------------
  
membership(:,1)=[pbu pmu psu zeu nsu nmu nbu]';

 %---------------------------------------------------------------