Simile tasks are challenging in natural language processing (NLP) because models require adequate world knowledge to produce predictions. In recent years, pre-trained language models (PLMs) have succeeded in NLP since they learn generic knowledge from a large corpus. The knowledge embedded in PLMs can be used for different kinds of Simile tasks. However, previous work usually explored one type of simile knowledge for a specific simile task, how to fully utilize different types of knowledge embedded in the PLMs requires further exploration. This paper proposes a self-verified method for exploring simile knowledge from PLMs, which allows the PLMs to leverage one type of simile knowledge to self-validate another. To this end, we first enhance PLMs with a novel multi-level simile recognition (MLSR) task that trains PLMs to evaluate the quality of similes. Then the PLMs leverage this evaluation score to assist the simile interpretation and generation tasks. In this way, we connect different types of simile knowledge in PLMs and make better use of them. Experiments on different pre-trained models and multiple publicly available datasets show that our method works for different kinds of PLMs and can explore more accurate simile knowledge for PLMs. Our code/data will be released on GitHub.

A simile is a figure of speech that compares two different things (called the tenor and the vehicle) via shared properties. The tenor and the vehicle are usually connected with comparator words such as “like” or “as”. The simile phenomena are unique and complex in a real-life dialogue scene where the tenor and the vehicle can be verbal phrases or sentences, mentioned by different speakers, exist in different sentences, or occur in reversed order. However, the current simile research usually focuses on similes in a triplet tuple (tenor, property, vehicle) or a single sentence where the tenor and vehicle are usually entities or noun phrases, which could not reflect complex simile phenomena in real scenarios. In this paper, we propose a novel and high-quality multilingual simile dialogue (MSD) dataset to facilitate the study of complex simile phenomena. The MSD is the largest manually annotated simile data (~21K) and it contains both English and Chinese data. Meanwhile, the MSD data can also be used on dialogue tasks to test the ability of dialogue systems when using similes. We design 3 simile tasks (recognition, interpretation, and generation) and 2 dialogue tasks (retrieval and generation) with MSD. For each task, we provide experimental results from strong pre-trained or state-of-the-art models. The experiments demonstrate the challenge of MSD and we will release the data/code on GitHub.

We participate in the 11th Dialog System Technology Challenges (DSTC) track-5 called Task-oriented Conversational Modeling with Subjective Knowledge. Introducing subjective knowledge into task-oriented dialogue (TOD) can help the DS to understand variables of subjective user needs and to suit more dialogue scenarios. Track-5 includes several sub-tasks: 1) knowledge-seeking turn detection; 2) knowledge entity tracking; 3) knowledge entry selection; and 4) use of the selected knowledge entries for response generation. Besides the challenges of each sub-tasks own, there are two challenges across different sub-tasks. The first is that there are multiple valid knowledge entries for each knowledge-seeking turn, the accuracy of the knowledge entry selection is important for the quality of response generation. The second challenge is how to address the unseen dialogue/entities/entries in the validation and the test set. In this paper, we propose a difference-aware ensemble method to address these sub-tasks and the two challenges mentioned above. Our method helps to obtain more robust results and performs well on unseen instances. Among all the submissions for the test set, our method ranks 1st on the knowledge-seeking turn detection task and achieves 3rd on the overall automatic evaluation score. Our code and data will be released on GitHub.