Shuai Wang


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Sequential Cross-Document Coreference Resolution
Emily Allaway | Shuai Wang | Miguel Ballesteros
Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing

Relating entities and events in text is a key component of natural language understanding. Cross-document coreference resolution, in particular, is important for the growing interest in multi-document analysis tasks. In this work we propose a new model that extends the efficient sequential prediction paradigm for coreference resolution to cross-document settings and achieves competitive results for both entity and event coreference while providing strong evidence of the efficacy of both sequential models and higher-order inference in cross-document settings. Our model incrementally composes mentions into cluster representations and predicts links between a mention and the already constructed clusters, approximating a higher-order model. In addition, we conduct extensive ablation studies that provide new insights into the importance of various inputs and representation types in coreference.

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Detecting Domain Polarity-Changes of Words in a Sentiment Lexicon
Shuai Wang | Guangyi Lv | Sahisnu Mazumder | Bing Liu
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

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Multi-Task Learning and Adapted Knowledge Models for Emotion-Cause Extraction
Elsbeth Turcan | Shuai Wang | Rishita Anubhai | Kasturi Bhattacharjee | Yaser Al-Onaizan | Smaranda Muresan
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

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Learning from Miscellaneous Other-Class Words for Few-shot Named Entity Recognition
Meihan Tong | Shuai Wang | Bin Xu | Yixin Cao | Minghui Liu | Lei Hou | Juanzi Li
Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)

Few-shot Named Entity Recognition (NER) exploits only a handful of annotations to iden- tify and classify named entity mentions. Pro- totypical network shows superior performance on few-shot NER. However, existing prototyp- ical methods fail to differentiate rich seman- tics in other-class words, which will aggravate overfitting under few shot scenario. To address the issue, we propose a novel model, Mining Undefined Classes from Other-class (MUCO), that can automatically induce different unde- fined classes from the other class to improve few-shot NER. With these extra-labeled unde- fined classes, our method will improve the dis- criminative ability of NER classifier and en- hance the understanding of predefined classes with stand-by semantic knowledge. Experi- mental results demonstrate that our model out- performs five state-of-the-art models in both 1- shot and 5-shots settings on four NER bench- marks. We will release the code upon accep- tance. The source code is released on https: //


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Bayes-enhanced Lifelong Attention Networks for Sentiment Classification
Hao Wang | Shuai Wang | Sahisnu Mazumder | Bing Liu | Yan Yang | Tianrui Li
Proceedings of the 28th International Conference on Computational Linguistics

The classic deep learning paradigm learns a model from the training data of a single task and the learned model is also tested on the same task. This paper studies the problem of learning a sequence of tasks (sentiment classification tasks in our case). After each sentiment classification task is learned, its knowledge is retained to help future task learning. Following this setting, we explore attention neural networks and propose a Bayes-enhanced Lifelong Attention Network (BLAN). The key idea is to exploit the generative parameters of naive Bayes to learn attention knowledge. The learned knowledge from each task is stored in a knowledge base and later used to build lifelong attentions. The constructed lifelong attentions are then used to enhance the attention of the network to help new task learning. Experimental results on product reviews from show the effectiveness of the proposed model.

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Automatic recognition of abdominal lymph nodes from clinical text
Yifan Peng | Sungwon Lee | Daniel C. Elton | Thomas Shen | Yu-xing Tang | Qingyu Chen | Shuai Wang | Yingying Zhu | Ronald Summers | Zhiyong Lu
Proceedings of the 3rd Clinical Natural Language Processing Workshop

Lymph node status plays a pivotal role in the treatment of cancer. The extraction of lymph nodes from radiology text reports enables large-scale training of lymph node detection on MRI. In this work, we first propose an ontology of 41 types of abdominal lymph nodes with a hierarchical relationship. We then introduce an end-to-end approach based on the combination of rules and transformer-based methods to detect these abdominal lymph node mentions and classify their types from the MRI radiology reports. We demonstrate the superior performance of a model fine-tuned on MRI reports using BlueBERT, called MriBERT. We find that MriBERT outperforms the rule-based labeler (0.957 vs 0.644 in micro weighted F1-score) as well as other BERT-based variations (0.913 - 0.928). We make the code and MriBERT publicly available at, with the hope that this method can facilitate the development of medical report annotators to produce labels from scratch at scale.

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Improving Event Detection via Open-domain Trigger Knowledge
Meihan Tong | Bin Xu | Shuai Wang | Yixin Cao | Lei Hou | Juanzi Li | Jun Xie
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Event Detection (ED) is a fundamental task in automatically structuring texts. Due to the small scale of training data, previous methods perform poorly on unseen/sparsely labeled trigger words and are prone to overfitting densely labeled trigger words. To address the issue, we propose a novel Enrichment Knowledge Distillation (EKD) model to leverage external open-domain trigger knowledge to reduce the in-built biases to frequent trigger words in annotations. Experiments on benchmark ACE2005 show that our model outperforms nine strong baselines, is especially effective for unseen/sparsely labeled trigger words. The source code is released on

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Severing the Edge Between Before and After: Neural Architectures for Temporal Ordering of Events
Miguel Ballesteros | Rishita Anubhai | Shuai Wang | Nima Pourdamghani | Yogarshi Vyas | Jie Ma | Parminder Bhatia | Kathleen McKeown | Yaser Al-Onaizan
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)

In this paper, we propose a neural architecture and a set of training methods for ordering events by predicting temporal relations. Our proposed models receive a pair of events within a span of text as input and they identify temporal relations (Before, After, Equal, Vague) between them. Given that a key challenge with this task is the scarcity of annotated data, our models rely on either pretrained representations (i.e. RoBERTa, BERT or ELMo), transfer and multi-task learning (by leveraging complementary datasets), and self-training techniques. Experiments on the MATRES dataset of English documents establish a new state-of-the-art on this task.

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A Knowledge-Driven Approach to Classifying Object and Attribute Coreferences in Opinion Mining
Jiahua Chen | Shuai Wang | Sahisnu Mazumder | Bing Liu
Findings of the Association for Computational Linguistics: EMNLP 2020

Classifying and resolving coreferences of objects (e.g., product names) and attributes (e.g., product aspects) in opinionated reviews is crucial for improving the opinion mining performance. However, the task is challenging as one often needs to consider domain-specific knowledge (e.g., iPad is a tablet and has aspect resolution) to identify coreferences in opinionated reviews. Also, compiling a handcrafted and curated domain-specific knowledge base for each domain is very time consuming and arduous. This paper proposes an approach to automatically mine and leverage domain-specific knowledge for classifying objects and attribute coreferences. The approach extracts domain-specific knowledge from unlabeled review data and trains a knowledgeaware neural coreference classification model to leverage (useful) domain knowledge together with general commonsense knowledge for the task. Experimental evaluation on realworld datasets involving five domains (product types) shows the effectiveness of the approach

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Resource-Enhanced Neural Model for Event Argument Extraction
Jie Ma | Shuai Wang | Rishita Anubhai | Miguel Ballesteros | Yaser Al-Onaizan
Findings of the Association for Computational Linguistics: EMNLP 2020

Event argument extraction (EAE) aims to identify the arguments of an event and classify the roles that those arguments play. Despite great efforts made in prior work, there remain many challenges: (1) Data scarcity. (2) Capturing the long-range dependency, specifically, the connection between an event trigger and a distant event argument. (3) Integrating event trigger information into candidate argument representation. For (1), we explore using unlabeled data. For (2), we use Transformer that uses dependency parses to guide the attention mechanism. For (3), we propose a trigger-aware sequence encoder with several types of trigger-dependent sequence representations. We also support argument extraction either from text annotated with gold entities or from plain text. Experiments on the English ACE 2005 benchmark show that our approach achieves a new state-of-the-art.


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Lifelong and Interactive Learning of Factual Knowledge in Dialogues
Sahisnu Mazumder | Bing Liu | Shuai Wang | Nianzu Ma
Proceedings of the 20th Annual SIGdial Meeting on Discourse and Dialogue

Dialogue systems are increasingly using knowledge bases (KBs) storing real-world facts to help generate quality responses. However, as the KBs are inherently incomplete and remain fixed during conversation, it limits dialogue systems’ ability to answer questions and to handle questions involving entities or relations that are not in the KB. In this paper, we make an attempt to propose an engine for Continuous and Interactive Learning of Knowledge (CILK) for dialogue systems to give them the ability to continuously and interactively learn and infer new knowledge during conversations. With more knowledge accumulated over time, they will be able to learn better and answer more questions. Our empirical evaluation shows that CILK is promising.


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Target-Sensitive Memory Networks for Aspect Sentiment Classification
Shuai Wang | Sahisnu Mazumder | Bing Liu | Mianwei Zhou | Yi Chang
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Aspect sentiment classification (ASC) is a fundamental task in sentiment analysis. Given an aspect/target and a sentence, the task classifies the sentiment polarity expressed on the target in the sentence. Memory networks (MNs) have been used for this task recently and have achieved state-of-the-art results. In MNs, attention mechanism plays a crucial role in detecting the sentiment context for the given target. However, we found an important problem with the current MNs in performing the ASC task. Simply improving the attention mechanism will not solve it. The problem is referred to as target-sensitive sentiment, which means that the sentiment polarity of the (detected) context is dependent on the given target and it cannot be inferred from the context alone. To tackle this problem, we propose the target-sensitive memory networks (TMNs). Several alternative techniques are designed for the implementation of TMNs and their effectiveness is experimentally evaluated.


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Personal Attributes Extraction in Chinese Text Bakeoff in CLP 2014: Overview
Ruifeng Xu | Shuai Wang | Feng Shi | Jian Xu
Proceedings of The Third CIPS-SIGHAN Joint Conference on Chinese Language Processing