A currency evaluation device for receiving a stack of currency bills and rapidly evaluating all the bills in the stack. While, in some cases, it is possible to install intermediate wireless network nodes to hop through long expanses between distant wireless network nodes, it is desirable for distantly spaced wireless network nodes to reach one another through a single transit link. The sensor unit comprises, a filter for removing airborne pollutants from the air flow. A second preliminary presence probability distribution is determined using the presence probability distribution for the preceding acquisition time and a migration probability distribution with the substance migrating from first vascular locations to second vascular locations. The probe assembly may include an array of contact pins configured to mate with conductive pads on the device under test when the probe assembly is installed on the probe bar gantry assembly. Thus, the BIST write is capable of being performed in a same cycle as the BIST search permitting at-speed BIST.