We propose two interactive evolutionary computation (IEC) methods that allow users to actively participate in an EC search. This is different from a conventional IEC in which the search and evaluation are performed by the EC and the user, respectively. The first method is one in which information obtained from an IEC search is explicitly incorporated into the EC search for the next generation using on-line knowledge embedding. The second is a method that introduces a 2-D visualization of an n-D searching space. The acceleration of EC convergence and the user interface were experimentally evaluated for both methods.