The present invention relates to air bag tethers and to a pattern-wise arrangement of such tethers in relation to air bag panels on a fabric blank. An electrode actuating device, most preferably a digital-to-digital converter, operates actuating electrodes so that at least one electrode is actuated as a function of values of more than one bit of the input data word. The computer transmits a user notification including the estimate of the time at which the portion of content will be presented and the level of confidence in the accuracy of the estimate. The computer identifies a knowledge domain of the sample document and identifies at least one of the annotators based on the knowledge domain of the sample document. Because the support structure is not connected to the part, the support structure can be removed freely without any post-processing step. In one embodiment, rock detectors are used to steer the cutting of the leading drum andor the trailing drum a long-wall mining system.