Natural Language Understanding (NLU) is one of the most critical components of task-oriented dialogue, and it is often considered as an intent classification task. To achieve outstanding intent identification performance, system designers often need to hire a large number of domain experts to label the data, which is inefficient and costly. To address this problem, researchers’ attention has gradually shifted to automatic intent clustering methods, which employ low-resource unsupervised approaches to solve classification problems. The classical framework for clustering is deep clustering, which uses deep neural networks (DNNs) to jointly optimize non-clustering loss and clustering loss. However, for new conversational domains or services, utterances required to assign intents are scarce and the performance of DNNs is often dependent on large amounts of data. In addition, although re-clustering with k-means algorithm after training the network usually leads to better results, k-means methods often suffer from poor stability. To address these problems, we propose an effective two-stage progressive approach to refine the clustering. Firstly, we pre-train the network with contrastive loss using all conversations data and then optimize the clustering loss and contrastive loss simultaneously. Secondly, we propose adaptive progressive k-means to alleviate the randomness of vanilla k-means, achieving better performance and smaller deviation. Our method ranks second in DSTC11 Track2 Task 1, a benchmark for intent clustering of task-oriented dialogue, demonstrating the superiority and effectiveness of our method.

In this paper, we built several pre-trained models to participate SemEval-2020 Task 12: Multilingual Offensive Language Identification in Social Media. In the common task of Offensive Language Identification in Social Media, pre-trained models such as Bidirectional Encoder Representation from Transformer (BERT) have achieved good results. We preprocess the dataset by the language habits of users in social network. Considering the data imbalance in OffensEval, we screened the newly provided machine annotation samples to construct a new dataset. We use the dataset to fine-tune the Robustly Optimized BERT Pretraining Approach (RoBERTa). For the English subtask B, we adopted the method of adding Auxiliary Sentences (AS) to transform the single-sentence classification task into a relationship recognition task between sentences. Our team UJNLP wins the ranking 16th of 85 in English subtask A (Offensive language identification).