A two-transistor non-volatile memory cell is formed in a semiconductor body. The floating seal is designed as a single piece plate with inner and outer annular seals. Rover and base smart antenna units are interchangeable in the system. The relief structures of the mosaic surfaces differ only in respect of spatial frequency, the difference in the spatial frequencies in the adjacent mosaic surfaces being at most 40 linesmm. An object-oriented database is expressed as a plurality of entries in a transient, hierarchical, object-oriented form. The checkpoints further comprise site managers to communicate information, gathered by RFID readers from RFID tags on containers, to the control center.