An object of the present invention is to provide a total reflection measuring apparatus which, while visually observing a specific minute area of a measurement object, is capable of efficiently obtaining optical data on the basis of the total reflection measurement. The tunable capacitor comprises first and second substrates having first and second capacitor plates disposed, respectively, thereon. Such a brake assembly is well-suited for a variety of applications including vehicle brakes such as aircraft brakes. One method includes the steps of donning the orthotic device about the patient’s chest, connecting the free end portions of the orthotic device together with the mechanical advantage device in the expanded state, and pulling the drawstring element a selected distance to move the mechanical advantage device from the expanded state to the contracted state for a desired level of tightening. After receiving the information from the master station the number of times of multicast transmission notified, a slave station identifies lacking information in information to be received.