1.IntroductionLetnbeaboundedopendomaininH"(n22)withsmoothboundaryr,uu(s)betheouternormalofrat8.GivenavectorxoEE",denotem(x)=x--xo(xER"),R=sup{im(x)IIxEfi}.SetWeconsiderthefollowingwaveequstiononnwithboundaryfeedback:whereK=(m'u)k(8),L=f(m'u),with(,n...