Boundary stabilization and observation of a multi-dimensional unstable heat equation

In this paper, we consider the boundary stabilization and observation of the multidimensional unstable heat equation. Since we consider the heat equation in a general domain, the usual partial differential equation back-stepping method is hard to apply to the considered problems. The unstable dynamics of the heat equation are treated by combining the finite-dimensional spectral truncation method and the dynamics compensation method. By introducing additional finite-dimensional actuator/sensor dynamics, the unbounded stabilization/observation turns to be a bounded one. As a result, the controller/observer design becomes more easier. Both the full state feedback stabilizer and the state observer are designed. The exponential stability of the closed-loop and the wellposedness of the observer are obtained.