%
%    Plot the example from Brynjarsdottir and O'Hagan
%
  
  n = 11;
  dx = (4-0.2)/(n-1);
  x = 0:0.01:6;
  xd = 0.2:dx:4;

  theta = 0.65;
  a = 20;
  sigma = 0.01;
  error = sigma*randn(1,n);
  
  f = theta*x;
  zeta = theta*x./(ones(size(x)) + x/a);
  zeta_dis = theta*xd./(ones(size(xd)) + xd/a) + error;

  figure(1)
  plot(x,f,'k-',x,zeta,'b--','linewidth',3)
  hold on
  plot(xd,zeta_dis,'bo','linewidth',5)
  hold off
  set(gca,'Fontsize',[23]);
  xlabel('x')
  ylabel('Responses')
  legend('Mathematical Model','True Process','Observations','Location','NorthWest')