They also tried using long short-term memory (LSTM) (Hochreiter and Schmidhuber, 1997), bidirectional LSTM and ensemble method with all of those neural network architectures and achieved the best results on the Ubuntu Dialogues Corpus dataset.
mobile, office, photo, tv/video, accessories, and home appliance as top-level categories, and specific categories like galaxy s7, tablet, led tv, and others are used.