A foldable traffic sign system comprises a relatively rigid sign panel and a plurality of folding lines disposed in the sign panel, for permitting ready folding of the sign panel into a substantially smaller configuration. The contamination level of the inner wall of the system is identified by measuring the spectrum of the X-rays emitted from the inner wall due to irradiation of a charged particle beam or a recoil electron. The Minimum Mean Square Error estimates of the phase shifted pilot signals are computed and the MMSE estimates are used to estimate phase errors for the symbols. The formation of electroceramic phases of pervoskite structure and fine crystallinity are activated by mechanical energy or a combination of mechanical energy and thermal energy. The raised boss portion lies at the mated flats of the juncture of the first and second blocks, which are chamfered to permit part of the boss to locate in each of the chamfers. A corresponding method, computer readable medium, and computer program product are also disclosed.