A signal x is reconstructed by measuring the signal x as a vector y of measurements yi, wherein the measurements yi are distorted, and each measurement yi has an associated value. The hopper bag and hopper frame are connected to a lawn sweeper unit using a hopper rod which is inserted into two slots at the ends of two hopper support bars and secured within the slots by two corresponding latch plates, one latch plate at each end of the two hopper support bars. A determination is made as to whether one address in the second address format is available to communicate with the second network device. A part which performs clock exchange with respect to valid path information indicated by head position. Nodes of the tree can be streamed into memory so that only a portion of a large tree is present in memory at any time.