An apparatus and method to test components in a semiconductor test structure. Electrodes for applying an electric field across at least some of the liquid crystal material are on at least one cell wall. Each provider is associated with a resource and acts as the manager for the resource when interfacing with the resource manager. There is only one type of metric possible for the largest granular policer, so the only way to implement multiple system-wide metrics is to repeat the hierarchy multiple times over, which adds to the delay of the packet and the complexity of the router. After respective periods of time in which a door of the appliance is not opened, the controller switches to first and second low power modes to conserve energy. The attainable states for both descriptions are preferably determined by model checking.