A method for improving program performance including reordering a global data area of a program and for each load instruction referencing global variables within range of the immediate part of an add immediate instruction from a TOC anchor, replacing the load instruction with an add immediate instruction. This method codes a block of information symbols S=) belonging to a 2-PPM modulation or 2-PPM-M\u2032-PAM composite modulation alphabet with M\u2032\u22672, into a sequence of vectors, the components of a vector being intended to modulate a UWB pulse signal for a radiative element of said system and for a given transmission interval. The queue servers are selected from a pool of available queue servers to optimize the performance of a distributed strict queue system. The wall structure of the outer stent has a predetermined length and a flexible stretchable material layer arranged between the inner stent and the outer stent.