A wireless optical communication system can reduce the power consumption needed for light emission by a controlled node and suppress a modulated signal component, other than the modulated signal of input data for transmission, in the modulated signal components carried by the light output of the controlled node. The assembly includes a shell-like locker, a track mechanism for moveably connecting the locker to an aircraft structure between a closed position and an open position, and a lifting mechanism for relieving the muscle power required for a user to move the locker between the closed position and the open position. Each of the sidewalls has an integral extension which extends into and is detachable from the shelf member. a radar system, are processed by an extended Kalman filter to provide an unconstrained estimate of the state of a target vehicle. Memory devices and methods of forming memory devices including forming one or more insulating layers on sidewalls of all or part of a plurality of lower electrodes andor a plurality of memory elements. The statements are preferably arranged in a matrix according to subject area and degree of difficulty.