Intent detection is at the core of task-oriented dialogue systems. Existing intent detection systems are typically trained with a large amount of data over a predefined set of intent classes. However, newly emerged intents in multiple domains are commonplace in the real world. And it is time-consuming and impractical for dialogue systems to re-collect enough annotated data and re-train the model. These limitations call for an intent detection system that could continually recognize new intents with very few labeled examples. In this work, we study the Continual Few-shot Intent Detection (CFID) problem and construct a benchmark consisting of nine tasks with multiple domains and imbalanced classes. To address the key challenges of (a) catastrophic forgetting during continuous learning and (b) negative knowledge transfer across tasks, we propose the Prefix-guided Lightweight Encoder (PLE) with three auxiliary strategies, namely Pseudo Samples Replay (PSR), Teacher Knowledge Transfer (TKT) and Dynamic Weighting Replay (DWR). Extensive experiments demonstrate the effectiveness and efficiency of our method in preventing catastrophic forgetting and encouraging positive knowledge transfer across tasks.

Unsupervised domain adaptation aims to transfer knowledge from a labeled but heterogeneous source domain to an unlabeled target domain, alleviating the labeling efforts. Early advances in domain adaptation focus on invariant representations learning (IRL) methods to align domain distributions. Recent studies further utilize semi-supervised learning (SSL) methods to regularize domain-invariant representations based on the cluster assumption, making the category boundary more clear. However, the misalignment in the IRL methods might be intensified by SSL methods if the target instances are more proximate to the wrong source centroid, resulting in incompatibility between these techniques. In this paper, we hypothesize this phenomenon derives from the distraction of the source domain, and further give a novel two-stage adaptation framework to adapt the model toward the target domain. In addition, we propose DCAN to reduce the misalignment in IRL methods in the first stage, and we propose PCST to encode the semantic structure of unlabeled target data in the second stage. Extensive experiments demonstrate that our method outperforms current state-of-the-art methods on four benchmarks (Office-31, ImageCLEF-DA, Office-Home, and VisDA-2017).

Stylized image captioning systems aim to generate a caption not only semantically related to a given image but also consistent with a given style description. One of the biggest challenges with this task is the lack of sufficient paired stylized data. Many studies focus on unsupervised approaches, without considering from the perspective of data augmentation. We begin with the observation that people may recall similar emotions when they are in similar scenes, and often express similar emotions with similar style phrases, which underpins our data augmentation idea. In this paper, we propose a novel Extract-Retrieve-Generate data augmentation framework to extract style phrases from small-scale stylized sentences and graft them to large-scale factual captions. First, we design the emotional signal extractor to extract style phrases from small-scale stylized sentences. Second, we construct the plugable multi-modal scene retriever to retrieve scenes represented with pairs of an image and its stylized caption, which are similar to the query image or caption in the large-scale factual data. In the end, based on the style phrases of similar scenes and the factual description of the current scene, we build the emotion-aware caption generator to generate fluent and diversified stylized captions for the current scene. Extensive experimental results show that our framework can alleviate the data scarcity problem effectively. It also significantly boosts the performance of several existing image captioning models in both supervised and unsupervised settings, which outperforms the state-of-the-art stylized image captioning methods in terms of both sentence relevance and stylishness by a substantial margin.

Past progress on neural models has proven that named entity recognition is no longer a problem if we have enough labeled data.However, collecting enough data and annotating them are labor-intensive, time-consuming, and expensive.In this paper, we decompose the sentence into two parts: entity and context, and rethink the relationship between them and model performance from a causal perspective.Based on this, we propose the Counterfactual Generator, which generates counterfactual examples by the interventions on the existing observational examples to enhance the original dataset.Experiments across three datasets show that our method improves the generalization ability of models under limited observational examples.Besides, we provide a theoretical foundation by using a structural causal model to explore the spurious correlations between input features and output labels.We investigate the causal effects of entity or context on model performance under both conditions: the non-augmented and the augmented.Interestingly, we find that the non-spurious correlations are more located in entity representation rather than context representation.As a result, our method eliminates part of the spurious correlations between context representation and output labels.The code is available at https://github.com/xijiz/cfgen.