An electromagnetic band-gap structure includes a circuit board, a ground plane and a plurality of electromagnetic band-gap units. The plurality of memories store an input signal in a way such that the input signal is divided into a plurality of regional signals to correspond to the plurality of memories. The power-operated dog clutch associated with the low and the top gear are used during downshifts and upshifts, respectively, to actuate a clutch assembly for synchronizing the speed of the input shaft and the selected gear prior to engagement of its corresponding dog clutch. For each output macroblock having a first value for the first attribute, the second attribute is decided at least in part by evaluating one or more error criteria, the error criteria being responsive to the second attribute of a corresponding input macroblock. According to the invention, each support means takes the form of a board comprising an outer frame into which are inserted, removably and with friction, at least two inner frames, into each of which are inserted, removably and with friction, at least two labels bearing the information. At least one of the first and second variable power optical components is stationary on the optical axis and comprises at least two liquids with different refractive properties and at least one variable shape contact surface between the two liquids, with variations in the shape of the contact surface producing a change of optical power in the optical system.