We explore active learning (AL) for improving the accuracy of new domains in a natural language understanding (NLU) system. We propose an algorithm called Majority-CRF that uses an ensemble of classification models to guide the selection of relevant utterances, as well as a sequence labeling model to help prioritize informative examples. Experiments with three domains show that Majority-CRF achieves 6.6 -9 relative error rate reduction compared to random sampling with the same annotation budget, and statistically significant improvements compared to other AL approaches. Additionally, case studies with human-in-the-loop AL on six new domains show 4.6 -9 improvement on an existing NLU system.
An electrical resistance-roll seam welding machine having a pair of welding rolls or rollers and at least one electrode wire which is guided from a supply station for the infeed of fresh welding wire by means of at least one of the welding rolls to a collecting station or location for used or consumed wire. The electrode wire can be brought into contact by means of the welding rolls with the workpiece which is to be welded. A brake device is arranged between the supply station and the welding rolls and a tension device for the electrode wire is disposed between the welding rolls and the collecting station or location. The sum of the tension force exerted by the tension device upon the wire and the brake force exerted by the brake device upon the wire is great enough in order to continuously maintain in tensioned state the electrode wire through its path of travel between the brake device and the tension device. At least one of the welding rolls is operatively coupled with a drive device which imparts to the electrode wire which is guided by means of said one welding roll a speed of travel coinciding with the desired feed speed of the workpieces during the formation of the welding seam. The difference between the tension force exerted by the tension device upon the wire and the brake force exerted by the brake device upon the wire is smaller than the entrainment force exerted by the periphery of said one welding roll upon the electrode wire.