Exponential stabilization for Timoshenko beam with different delays in the boundary control

In this paper, we consider the exponential stabilization for Timoshenko beam with different delays in the boundary control. Suppose that the controller outputs are of the form
$\alpha _{1}u_{1}(t)+\beta _1u_1(t-\tau _{1})+\gamma _{1}u_1 (t-\tau _{2})$
and
$\alpha _{2}u_{2}(t)+\beta _2u_2(t-\tau _{1})+\gamma _{2}u_2(t-\tau _{2}),$
where
$u_1(t)$
and
$u_2(t)$
are the inputs of boundary controllers.