## Set up u_star
  u_star = ppp_ustar(A_u_sim,1,t,0,0,n_u-n_U);

  ## Simulate
  par(i_ppp_sim(:,3)) = U;		# Update the simulation ppp weights
  [y_sim,x] = eval(sprintf("%s_sim(x_0_sim, par, simpar_sim, u_star);", \
			     system_name_sim));
  x_0_sim  = x(n_t,:)';     # Extract state for next time
			   system_name_sim));
  x_0_sim  = x(n_t,:)';		# Extract state for next time
  u_sim = (u_star*U);
endfunction