Wanxiang Che


2021

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Adversarial Training for Machine Reading Comprehension with Virtual Embeddings
Ziqing Yang | Yiming Cui | Chenglei Si | Wanxiang Che | Ting Liu | Shijin Wang | Guoping Hu
Proceedings of *SEM 2021: The Tenth Joint Conference on Lexical and Computational Semantics

Adversarial training (AT) as a regularization method has proved its effectiveness on various tasks. Though there are successful applications of AT on some NLP tasks, the distinguishing characteristics of NLP tasks have not been exploited. In this paper, we aim to apply AT on machine reading comprehension (MRC) tasks. Furthermore, we adapt AT for MRC tasks by proposing a novel adversarial training method called PQAT that perturbs the embedding matrix instead of word vectors. To differentiate the roles of passages and questions, PQAT uses additional virtual P/Q-embedding matrices to gather the global perturbations of words from passages and questions separately. We test the method on a wide range of MRC tasks, including span-based extractive RC and multiple-choice RC. The results show that adversarial training is effective universally, and PQAT further improves the performance.

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Proceedings of the 20th Chinese National Conference on Computational Linguistics
Sheng Li (李生) | Maosong Sun (孙茂松) | Yang Liu (刘洋) | Hua Wu (吴华) | Kang Liu (刘康) | Wanxiang Che (车万翔) | Shizhu He (何世柱) | Gaoqi Rao (饶高琦)
Proceedings of the 20th Chinese National Conference on Computational Linguistics

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GL-GIN: Fast and Accurate Non-Autoregressive Model for Joint Multiple Intent Detection and Slot Filling
Libo Qin | Fuxuan Wei | Tianbao Xie | Xiao Xu | Wanxiang Che | Ting Liu
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)

Multi-intent SLU can handle multiple intents in an utterance, which has attracted increasing attention. However, the state-of-the-art joint models heavily rely on autoregressive approaches, resulting in two issues: slow inference speed and information leakage. In this paper, we explore a non-autoregressive model for joint multiple intent detection and slot filling, achieving more fast and accurate. Specifically, we propose a Global-Locally Graph Interaction Network (GL-GIN) where a local slot-aware graph interaction layer is proposed to model slot dependency for alleviating uncoordinated slots problem while a global intent-slot graph interaction layer is introduced to model the interaction between multiple intents and all slots in the utterance. Experimental results on two public datasets show that our framework achieves state-of-the-art performance while being 11.5 times faster.

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Discovering Dialog Structure Graph for Coherent Dialog Generation
Jun Xu | Zeyang Lei | Haifeng Wang | Zheng-Yu Niu | Hua Wu | Wanxiang Che
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)

Learning discrete dialog structure graph from human-human dialogs yields basic insights into the structure of conversation, and also provides background knowledge to facilitate dialog generation. However, this problem is less studied in open-domain dialogue. In this paper, we conduct unsupervised discovery of discrete dialog structure from chitchat corpora, and then leverage it to facilitate coherent dialog generation in downstream systems. To this end, we present an unsupervised model, Discrete Variational Auto-Encoder with Graph Neural Network (DVAE-GNN), to discover discrete hierarchical latent dialog states (at the level of both session and utterance) and their transitions from corpus as a dialog structure graph. Then we leverage it as background knowledge to facilitate dialog management in a RL based dialog system. Experimental results on two benchmark corpora confirm that DVAE-GNN can discover meaningful dialog structure graph, and the use of dialog structure as background knowledge can significantly improve multi-turn coherence.

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LayoutLMv2: Multi-modal Pre-training for Visually-rich Document Understanding
Yang Xu | Yiheng Xu | Tengchao Lv | Lei Cui | Furu Wei | Guoxin Wang | Yijuan Lu | Dinei Florencio | Cha Zhang | Wanxiang Che | Min Zhang | Lidong Zhou
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)

Pre-training of text and layout has proved effective in a variety of visually-rich document understanding tasks due to its effective model architecture and the advantage of large-scale unlabeled scanned/digital-born documents. We propose LayoutLMv2 architecture with new pre-training tasks to model the interaction among text, layout, and image in a single multi-modal framework. Specifically, with a two-stream multi-modal Transformer encoder, LayoutLMv2 uses not only the existing masked visual-language modeling task but also the new text-image alignment and text-image matching tasks, which make it better capture the cross-modality interaction in the pre-training stage. Meanwhile, it also integrates a spatial-aware self-attention mechanism into the Transformer architecture so that the model can fully understand the relative positional relationship among different text blocks. Experiment results show that LayoutLMv2 outperforms LayoutLM by a large margin and achieves new state-of-the-art results on a wide variety of downstream visually-rich document understanding tasks, including FUNSD (0.7895 to 0.8420), CORD (0.9493 to 0.9601), SROIE (0.9524 to 0.9781), Kleister-NDA (0.8340 to 0.8520), RVL-CDIP (0.9443 to 0.9564), and DocVQA (0.7295 to 0.8672).

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Consistency Regularization for Cross-Lingual Fine-Tuning
Bo Zheng | Li Dong | Shaohan Huang | Wenhui Wang | Zewen Chi | Saksham Singhal | Wanxiang Che | Ting Liu | Xia Song | Furu Wei
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)

Fine-tuning pre-trained cross-lingual language models can transfer task-specific supervision from one language to the others. In this work, we propose to improve cross-lingual fine-tuning with consistency regularization. Specifically, we use example consistency regularization to penalize the prediction sensitivity to four types of data augmentations, i.e., subword sampling, Gaussian noise, code-switch substitution, and machine translation. In addition, we employ model consistency to regularize the models trained with two augmented versions of the same training set. Experimental results on the XTREME benchmark show that our method significantly improves cross-lingual fine-tuning across various tasks, including text classification, question answering, and sequence labeling.

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A Closer Look into the Robustness of Neural Dependency Parsers Using Better Adversarial Examples
Yuxuan Wang | Wanxiang Che | Ivan Titov | Shay B. Cohen | Zhilin Lei | Ting Liu
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

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Dynamic Connected Networks for Chinese Spelling Check
Baoxin Wang | Wanxiang Che | Dayong Wu | Shijin Wang | Guoping Hu | Ting Liu
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

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Learning to Bridge Metric Spaces: Few-shot Joint Learning of Intent Detection and Slot Filling
Yutai Hou | Yongkui Lai | Cheng Chen | Wanxiang Che | Ting Liu
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

2020

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A Sentence Cloze Dataset for Chinese Machine Reading Comprehension
Yiming Cui | Ting Liu | Ziqing Yang | Zhipeng Chen | Wentao Ma | Wanxiang Che | Shijin Wang | Guoping Hu
Proceedings of the 28th International Conference on Computational Linguistics

Owing to the continuous efforts by the Chinese NLP community, more and more Chinese machine reading comprehension datasets become available. To add diversity in this area, in this paper, we propose a new task called Sentence Cloze-style Machine Reading Comprehension (SC-MRC). The proposed task aims to fill the right candidate sentence into the passage that has several blanks. We built a Chinese dataset called CMRC 2019 to evaluate the difficulty of the SC-MRC task. Moreover, to add more difficulties, we also made fake candidates that are similar to the correct ones, which requires the machine to judge their correctness in the context. The proposed dataset contains over 100K blanks (questions) within over 10K passages, which was originated from Chinese narrative stories. To evaluate the dataset, we implement several baseline systems based on the pre-trained models, and the results show that the state-of-the-art model still underperforms human performance by a large margin. We release the dataset and baseline system to further facilitate our community. Resources available through https://github.com/ymcui/cmrc2019

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Combining ResNet and Transformer for Chinese Grammatical Error Diagnosis
Shaolei Wang | Baoxin Wang | Jiefu Gong | Zhongyuan Wang | Xiao Hu | Xingyi Duan | Zizhuo Shen | Gang Yue | Ruiji Fu | Dayong Wu | Wanxiang Che | Shijin Wang | Guoping Hu | Ting Liu
Proceedings of the 6th Workshop on Natural Language Processing Techniques for Educational Applications

Grammatical error diagnosis is an important task in natural language processing. This paper introduces our system at NLPTEA-2020 Task: Chinese Grammatical Error Diagnosis (CGED). CGED aims to diagnose four types of grammatical errors which are missing words (M), redundant words (R), bad word selection (S) and disordered words (W). Our system is built on the model of multi-layer bidirectional transformer encoder and ResNet is integrated into the encoder to improve the performance. We also explore two ensemble strategies including weighted averaging and stepwise ensemble selection from libraries of models to improve the performance of single model. In official evaluation, our system obtains the highest F1 scores at identification level and position level. We also recommend error corrections for specific error types and achieve the second highest F1 score at correction level.

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HIT-SCIR at MRP 2020: Transition-based Parser and Iterative Inference Parser
Longxu Dou | Yunlong Feng | Yuqiu Ji | Wanxiang Che | Ting Liu
Proceedings of the CoNLL 2020 Shared Task: Cross-Framework Meaning Representation Parsing

This paper describes our submission system (HIT-SCIR) for the CoNLL 2020 shared task: Cross-Framework and Cross-Lingual Meaning Representation Parsing. The task includes five frameworks for graph-based meaning representations, i.e., UCCA, EDS, PTG, AMR, and DRG. Our solution consists of two sub-systems: transition-based parser for Flavor (1) frameworks (UCCA, EDS, PTG) and iterative inference parser for Flavor (2) frameworks (DRG, AMR). In the final evaluation, our system is ranked 3rd among the seven team both in Cross-Framework Track and Cross-Lingual Track, with the macro-averaged MRP F1 score of 0.81/0.69.

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Revisiting Pre-Trained Models for Chinese Natural Language Processing
Yiming Cui | Wanxiang Che | Ting Liu | Bing Qin | Shijin Wang | Guoping Hu
Findings of the Association for Computational Linguistics: EMNLP 2020

Bidirectional Encoder Representations from Transformers (BERT) has shown marvelous improvements across various NLP tasks, and consecutive variants have been proposed to further improve the performance of the pre-trained language models. In this paper, we target on revisiting Chinese pre-trained language models to examine their effectiveness in a non-English language and release the Chinese pre-trained language model series to the community. We also propose a simple but effective model called MacBERT, which improves upon RoBERTa in several ways, especially the masking strategy that adopts MLM as correction (Mac). We carried out extensive experiments on eight Chinese NLP tasks to revisit the existing pre-trained language models as well as the proposed MacBERT. Experimental results show that MacBERT could achieve state-of-the-art performances on many NLP tasks, and we also ablate details with several findings that may help future research. https://github.com/ymcui/MacBERT

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AGIF: An Adaptive Graph-Interactive Framework for Joint Multiple Intent Detection and Slot Filling
Libo Qin | Xiao Xu | Wanxiang Che | Ting Liu
Findings of the Association for Computational Linguistics: EMNLP 2020

In real-world scenarios, users usually have multiple intents in the same utterance. Unfortunately, most spoken language understanding (SLU) models either mainly focused on the single intent scenario, or simply incorporated an overall intent context vector for all tokens, ignoring the fine-grained multiple intents information integration for token-level slot prediction. In this paper, we propose an Adaptive Graph-Interactive Framework (AGIF) for joint multiple intent detection and slot filling, where we introduce an intent-slot graph interaction layer to model the strong correlation between the slot and intents. Such an interaction layer is applied to each token adaptively, which has the advantage to automatically extract the relevant intents information, making a fine-grained intent information integration for the token-level slot prediction. Experimental results on three multi-intent datasets show that our framework obtains substantial improvement and achieves the state-of-the-art performance. In addition, our framework achieves new state-of-the-art performance on two single-intent datasets.

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Slot-consistent NLG for Task-oriented Dialogue Systems with Iterative Rectification Network
Yangming Li | Kaisheng Yao | Libo Qin | Wanxiang Che | Xiaolong Li | Ting Liu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Data-driven approaches using neural networks have achieved promising performances in natural language generation (NLG). However, neural generators are prone to make mistakes, e.g., neglecting an input slot value and generating a redundant slot value. Prior works refer this to hallucination phenomenon. In this paper, we study slot consistency for building reliable NLG systems with all slot values of input dialogue act (DA) properly generated in output sentences. We propose Iterative Rectification Network (IRN) for improving general NLG systems to produce both correct and fluent responses. It applies a bootstrapping algorithm to sample training candidates and uses reinforcement learning to incorporate discrete reward related to slot inconsistency into training. Comprehensive studies have been conducted on multiple benchmark datasets, showing that the proposed methods have significantly reduced the slot error rate (ERR) for all strong baselines. Human evaluations also have confirmed its effectiveness.

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Towards Conversational Recommendation over Multi-Type Dialogs
Zeming Liu | Haifeng Wang | Zheng-Yu Niu | Hua Wu | Wanxiang Che | Ting Liu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

We focus on the study of conversational recommendation in the context of multi-type dialogs, where the bots can proactively and naturally lead a conversation from a non-recommendation dialog (e.g., QA) to a recommendation dialog, taking into account user’s interests and feedback. To facilitate the study of this task, we create a human-to-human Chinese dialog dataset DuRecDial (about 10k dialogs, 156k utterances), where there are multiple sequential dialogs for a pair of a recommendation seeker (user) and a recommender (bot). In each dialog, the recommender proactively leads a multi-type dialog to approach recommendation targets and then makes multiple recommendations with rich interaction behavior. This dataset allows us to systematically investigate different parts of the overall problem, e.g., how to naturally lead a dialog, how to interact with users for recommendation. Finally we establish baseline results on DuRecDial for future studies.

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Few-shot Slot Tagging with Collapsed Dependency Transfer and Label-enhanced Task-adaptive Projection Network
Yutai Hou | Wanxiang Che | Yongkui Lai | Zhihan Zhou | Yijia Liu | Han Liu | Ting Liu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

In this paper, we explore the slot tagging with only a few labeled support sentences (a.k.a. few-shot). Few-shot slot tagging faces a unique challenge compared to the other fewshot classification problems as it calls for modeling the dependencies between labels. But it is hard to apply previously learned label dependencies to an unseen domain, due to the discrepancy of label sets. To tackle this, we introduce a collapsed dependency transfer mechanism into the conditional random field (CRF) to transfer abstract label dependency patterns as transition scores. In the few-shot setting, the emission score of CRF can be calculated as a word’s similarity to the representation of each label. To calculate such similarity, we propose a Label-enhanced Task-Adaptive Projection Network (L-TapNet) based on the state-of-the-art few-shot classification model – TapNet, by leveraging label name semantics in representing labels. Experimental results show that our model significantly outperforms the strongest few-shot learning baseline by 14.64 F1 scores in the one-shot setting.

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Conversational Graph Grounded Policy Learning for Open-Domain Conversation Generation
Jun Xu | Haifeng Wang | Zheng-Yu Niu | Hua Wu | Wanxiang Che | Ting Liu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

To address the challenge of policy learning in open-domain multi-turn conversation, we propose to represent prior information about dialog transitions as a graph and learn a graph grounded dialog policy, aimed at fostering a more coherent and controllable dialog. To this end, we first construct a conversational graph (CG) from dialog corpora, in which there are vertices to represent “what to say” and “how to say”, and edges to represent natural transition between a message (the last utterance in a dialog context) and its response. We then present a novel CG grounded policy learning framework that conducts dialog flow planning by graph traversal, which learns to identify a what-vertex and a how-vertex from the CG at each turn to guide response generation. In this way, we effectively leverage the CG to facilitate policy learning as follows: (1) it enables more effective long-term reward design, (2) it provides high-quality candidate actions, and (3) it gives us more control over the policy. Results on two benchmark corpora demonstrate the effectiveness of this framework.

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Dynamic Fusion Network for Multi-Domain End-to-end Task-Oriented Dialog
Libo Qin | Xiao Xu | Wanxiang Che | Yue Zhang | Ting Liu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Recent studies have shown remarkable success in end-to-end task-oriented dialog system. However, most neural models rely on large training data, which are only available for a certain number of task domains, such as navigation and scheduling. This makes it difficult to scalable for a new domain with limited labeled data. However, there has been relatively little research on how to effectively use data from all domains to improve the performance of each domain and also unseen domains. To this end, we investigate methods that can make explicit use of domain knowledge and introduce a shared-private network to learn shared and specific knowledge. In addition, we propose a novel Dynamic Fusion Network (DF-Net) which automatically exploit the relevance between the target domain and each domain. Results show that our models outperforms existing methods on multi-domain dialogue, giving the state-of-the-art in the literature. Besides, with little training data, we show its transferability by outperforming prior best model by 13.9% on average.

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Document Modeling with Graph Attention Networks for Multi-grained Machine Reading Comprehension
Bo Zheng | Haoyang Wen | Yaobo Liang | Nan Duan | Wanxiang Che | Daxin Jiang | Ming Zhou | Ting Liu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Natural Questions is a new challenging machine reading comprehension benchmark with two-grained answers, which are a long answer (typically a paragraph) and a short answer (one or more entities inside the long answer). Despite the effectiveness of existing methods on this benchmark, they treat these two sub-tasks individually during training while ignoring their dependencies. To address this issue, we present a novel multi-grained machine reading comprehension framework that focuses on modeling documents at their hierarchical nature, which are different levels of granularity: documents, paragraphs, sentences, and tokens. We utilize graph attention networks to obtain different levels of representations so that they can be learned simultaneously. The long and short answers can be extracted from paragraph-level representation and token-level representation, respectively. In this way, we can model the dependencies between the two-grained answers to provide evidence for each other. We jointly train the two sub-tasks, and our experiments show that our approach significantly outperforms previous systems at both long and short answer criteria.

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TextBrewer: An Open-Source Knowledge Distillation Toolkit for Natural Language Processing
Ziqing Yang | Yiming Cui | Zhipeng Chen | Wanxiang Che | Ting Liu | Shijin Wang | Guoping Hu
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics: System Demonstrations

In this paper, we introduce TextBrewer, an open-source knowledge distillation toolkit designed for natural language processing. It works with different neural network models and supports various kinds of supervised learning tasks, such as text classification, reading comprehension, sequence labeling. TextBrewer provides a simple and uniform workflow that enables quick setting up of distillation experiments with highly flexible configurations. It offers a set of predefined distillation methods and can be extended with custom code. As a case study, we use TextBrewer to distill BERT on several typical NLP tasks. With simple configurations, we achieve results that are comparable with or even higher than the public distilled BERT models with similar numbers of parameters.

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Combining Self-Training and Self-Supervised Learning for Unsupervised Disfluency Detection
Shaolei Wang | Zhongyuan Wang | Wanxiang Che | Ting Liu
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)

Most existing approaches to disfluency detection heavily rely on human-annotated corpora, which is expensive to obtain in practice. There have been several proposals to alleviate this issue with, for instance, self-supervised learning techniques, but they still require human-annotated corpora. In this work, we explore the unsupervised learning paradigm which can potentially work with unlabeled text corpora that are cheaper and easier to obtain. Our model builds upon the recent work on Noisy Student Training, a semi-supervised learning approach that extends the idea of self-training. Experimental results on the commonly used English Switchboard test set show that our approach achieves competitive performance compared to the previous state-of-the-art supervised systems using contextualized word embeddings (e.g. BERT and ELECTRA).

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Recall and Learn: Fine-tuning Deep Pretrained Language Models with Less Forgetting
Sanyuan Chen | Yutai Hou | Yiming Cui | Wanxiang Che | Ting Liu | Xiangzhan Yu
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)

Deep pretrained language models have achieved great success in the way of pretraining first and then fine-tuning. But such a sequential transfer learning paradigm often confronts the catastrophic forgetting problem and leads to sub-optimal performance. To fine-tune with less forgetting, we propose a recall and learn mechanism, which adopts the idea of multi-task learning and jointly learns pretraining tasks and downstream tasks. Specifically, we introduce a Pretraining Simulation mechanism to recall the knowledge from pretraining tasks without data, and an Objective Shifting mechanism to focus the learning on downstream tasks gradually. Experiments show that our method achieves state-of-the-art performance on the GLUE benchmark. Our method also enables BERT-base to achieve better average performance than directly fine-tuning of BERT-large. Further, we provide the open-source RecAdam optimizer, which integrates the proposed mechanisms into Adam optimizer, to facility the NLP community.

2019

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Entity-Consistent End-to-end Task-Oriented Dialogue System with KB Retriever
Libo Qin | Yijia Liu | Wanxiang Che | Haoyang Wen | Yangming Li | Ting Liu
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

Querying the knowledge base (KB) has long been a challenge in the end-to-end task-oriented dialogue system. Previous sequence-to-sequence (Seq2Seq) dialogue generation work treats the KB query as an attention over the entire KB, without the guarantee that the generated entities are consistent with each other. In this paper, we propose a novel framework which queries the KB in two steps to improve the consistency of generated entities. In the first step, inspired by the observation that a response can usually be supported by a single KB row, we introduce a KB retrieval component which explicitly returns the most relevant KB row given a dialogue history. The retrieval result is further used to filter the irrelevant entities in a Seq2Seq response generation model to improve the consistency among the output entities. In the second step, we further perform the attention mechanism to address the most correlated KB column. Two methods are proposed to make the training feasible without labeled retrieval data, which include distant supervision and Gumbel-Softmax technique. Experiments on two publicly available task oriented dialog datasets show the effectiveness of our model by outperforming the baseline systems and producing entity-consistent responses.

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Cross-Lingual Machine Reading Comprehension
Yiming Cui | Wanxiang Che | Ting Liu | Bing Qin | Shijin Wang | Guoping Hu
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

Though the community has made great progress on Machine Reading Comprehension (MRC) task, most of the previous works are solving English-based MRC problems, and there are few efforts on other languages mainly due to the lack of large-scale training data.In this paper, we propose Cross-Lingual Machine Reading Comprehension (CLMRC) task for the languages other than English. Firstly, we present several back-translation approaches for CLMRC task which is straightforward to adopt. However, to exactly align the answer into source language is difficult and could introduce additional noise. In this context, we propose a novel model called Dual BERT, which takes advantage of the large-scale training data provided by rich-resource language (such as English) and learn the semantic relations between the passage and question in bilingual context, and then utilize the learned knowledge to improve reading comprehension performance of low-resource language. We conduct experiments on two Chinese machine reading comprehension datasets CMRC 2018 and DRCD. The results show consistent and significant improvements over various state-of-the-art systems by a large margin, which demonstrate the potentials in CLMRC task. Resources available: https://github.com/ymcui/Cross-Lingual-MRC

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A Stack-Propagation Framework with Token-Level Intent Detection for Spoken Language Understanding
Libo Qin | Wanxiang Che | Yangming Li | Haoyang Wen | Ting Liu
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

Intent detection and slot filling are two main tasks for building a spoken language understanding (SLU) system. The two tasks are closely tied and the slots often highly depend on the intent. In this paper, we propose a novel framework for SLU to better incorporate the intent information, which further guiding the slot filling. In our framework, we adopt a joint model with Stack-Propagation which can directly use the intent information as input for slot filling, thus to capture the intent semantic knowledge. In addition, to further alleviate the error propagation, we perform the token-level intent detection for the Stack-Propagation framework. Experiments on two publicly datasets show that our model achieves the state-of-the-art performance and outperforms other previous methods by a large margin. Finally, we use the Bidirectional Encoder Representation from Transformer (BERT) model in our framework, which further boost our performance in SLU task.

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Cross-Lingual BERT Transformation for Zero-Shot Dependency Parsing
Yuxuan Wang | Wanxiang Che | Jiang Guo | Yijia Liu | Ting Liu
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

This paper investigates the problem of learning cross-lingual representations in a contextual space. We propose Cross-Lingual BERT Transformation (CLBT), a simple and efficient approach to generate cross-lingual contextualized word embeddings based on publicly available pre-trained BERT models (Devlin et al., 2018). In this approach, a linear transformation is learned from contextual word alignments to align the contextualized embeddings independently trained in different languages. We demonstrate the effectiveness of this approach on zero-shot cross-lingual transfer parsing. Experiments show that our embeddings substantially outperform the previous state-of-the-art that uses static embeddings. We further compare our approach with XLM (Lample and Conneau, 2019), a recently proposed cross-lingual language model trained with massive parallel data, and achieve highly competitive results.

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A Span-Extraction Dataset for Chinese Machine Reading Comprehension
Yiming Cui | Ting Liu | Wanxiang Che | Li Xiao | Zhipeng Chen | Wentao Ma | Shijin Wang | Guoping Hu
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

Machine Reading Comprehension (MRC) has become enormously popular recently and has attracted a lot of attention. However, the existing reading comprehension datasets are mostly in English. In this paper, we introduce a Span-Extraction dataset for Chinese machine reading comprehension to add language diversities in this area. The dataset is composed by near 20,000 real questions annotated on Wikipedia paragraphs by human experts. We also annotated a challenge set which contains the questions that need comprehensive understanding and multi-sentence inference throughout the context. We present several baseline systems as well as anonymous submissions for demonstrating the difficulties in this dataset. With the release of the dataset, we hosted the Second Evaluation Workshop on Chinese Machine Reading Comprehension (CMRC 2018). We hope the release of the dataset could further accelerate the Chinese machine reading comprehension research. Resources are available: https://github.com/ymcui/cmrc2018

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HIT-SCIR at MRP 2019: A Unified Pipeline for Meaning Representation Parsing via Efficient Training and Effective Encoding
Wanxiang Che | Longxu Dou | Yang Xu | Yuxuan Wang | Yijia Liu | Ting Liu
Proceedings of the Shared Task on Cross-Framework Meaning Representation Parsing at the 2019 Conference on Natural Language Learning

This paper describes our system (HIT-SCIR) for CoNLL 2019 shared task: Cross-Framework Meaning Representation Parsing. We extended the basic transition-based parser with two improvements: a) Efficient Training by realizing Stack LSTM parallel training; b) Effective Encoding via adopting deep contextualized word embeddings BERT. Generally, we proposed a unified pipeline to meaning representation parsing, including framework-specific transition-based parsers, BERT-enhanced word representation, and post-processing. In the final evaluation, our system was ranked first according to ALL-F1 (86.2%) and especially ranked first in UCCA framework (81.67%).

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Generating Natural Language Adversarial Examples through Probability Weighted Word Saliency
Shuhuai Ren | Yihe Deng | Kun He | Wanxiang Che
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

We address the problem of adversarial attacks on text classification, which is rarely studied comparing to attacks on image classification. The challenge of this task is to generate adversarial examples that maintain lexical correctness, grammatical correctness and semantic similarity. Based on the synonyms substitution strategy, we introduce a new word replacement order determined by both the word saliency and the classification probability, and propose a greedy algorithm called probability weighted word saliency (PWWS) for text adversarial attack. Experiments on three popular datasets using convolutional as well as LSTM models show that PWWS reduces the classification accuracy to the most extent, and keeps a very low word substitution rate. A human evaluation study shows that our generated adversarial examples maintain the semantic similarity well and are hard for humans to perceive. Performing adversarial training using our perturbed datasets improves the robustness of the models. At last, our method also exhibits a good transferability on the generated adversarial examples.

2018

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Sequence-to-Sequence Data Augmentation for Dialogue Language Understanding
Yutai Hou | Yijia Liu | Wanxiang Che | Ting Liu
Proceedings of the 27th International Conference on Computational Linguistics

In this paper, we study the problem of data augmentation for language understanding in task-oriented dialogue system. In contrast to previous work which augments an utterance without considering its relation with other utterances, we propose a sequence-to-sequence generation based data augmentation framework that leverages one utterance’s same semantic alternatives in the training data. A novel diversity rank is incorporated into the utterance representation to make the model produce diverse utterances and these diversely augmented utterances help to improve the language understanding module. Experimental results on the Airline Travel Information System dataset and a newly created semantic frame annotation on Stanford Multi-turn, Multi-domain Dialogue Dataset show that our framework achieves significant improvements of 6.38 and 10.04 F-scores respectively when only a training set of hundreds utterances is represented. Case studies also confirm that our method generates diverse utterances.

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Sequence-to-Sequence Learning for Task-oriented Dialogue with Dialogue State Representation
Haoyang Wen | Yijia Liu | Wanxiang Che | Libo Qin | Ting Liu
Proceedings of the 27th International Conference on Computational Linguistics

Classic pipeline models for task-oriented dialogue system require explicit modeling the dialogue states and hand-crafted action spaces to query a domain-specific knowledge base. Conversely, sequence-to-sequence models learn to map dialogue history to the response in current turn without explicit knowledge base querying. In this work, we propose a novel framework that leverages the advantages of classic pipeline and sequence-to-sequence models. Our framework models a dialogue state as a fixed-size distributed representation and use this representation to query a knowledge base via an attention mechanism. Experiment on Stanford Multi-turn Multi-domain Task-oriented Dialogue Dataset shows that our framework significantly outperforms other sequence-to-sequence based baseline models on both automatic and human evaluation.

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Parsing Tweets into Universal Dependencies
Yijia Liu | Yi Zhu | Wanxiang Che | Bing Qin | Nathan Schneider | Noah A. Smith
Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long Papers)

We study the problem of analyzing tweets with universal dependencies (UD). We extend the UD guidelines to cover special constructions in tweets that affect tokenization, part-of-speech tagging, and labeled dependencies. Using the extended guidelines, we create a new tweet treebank for English (Tweebank v2) that is four times larger than the (unlabeled) Tweebank v1 introduced by Kong et al. (2014). We characterize the disagreements between our annotators and show that it is challenging to deliver consistent annotation due to ambiguity in understanding and explaining tweets. Nonetheless, using the new treebank, we build a pipeline system to parse raw tweets into UD. To overcome the annotation noise without sacrificing computational efficiency, we propose a new method to distill an ensemble of 20 transition-based parsers into a single one. Our parser achieves an improvement of 2.2 in LAS over the un-ensembled baseline and outperforms parsers that are state-of-the-art on other treebanks in both accuracy and speed.

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Towards Better UD Parsing: Deep Contextualized Word Embeddings, Ensemble, and Treebank Concatenation
Wanxiang Che | Yijia Liu | Yuxuan Wang | Bo Zheng | Ting Liu
Proceedings of the CoNLL 2018 Shared Task: Multilingual Parsing from Raw Text to Universal Dependencies

This paper describes our system (HIT-SCIR) submitted to the CoNLL 2018 shared task on Multilingual Parsing from Raw Text to Universal Dependencies. We base our submission on Stanford’s winning system for the CoNLL 2017 shared task and make two effective extensions: 1) incorporating deep contextualized word embeddings into both the part of speech tagger and parser; 2) ensembling parsers trained with different initialization. We also explore different ways of concatenating treebanks for further improvements. Experimental results on the development data show the effectiveness of our methods. In the final evaluation, our system was ranked first according to LAS (75.84%) and outperformed the other systems by a large margin.

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Distilling Knowledge for Search-based Structured Prediction
Yijia Liu | Wanxiang Che | Huaipeng Zhao | Bing Qin | Ting Liu
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Many natural language processing tasks can be modeled into structured prediction and solved as a search problem. In this paper, we distill an ensemble of multiple models trained with different initialization into a single model. In addition to learning to match the ensemble’s probability output on the reference states, we also use the ensemble to explore the search space and learn from the encountered states in the exploration. Experimental results on two typical search-based structured prediction tasks – transition-based dependency parsing and neural machine translation show that distillation can effectively improve the single model’s performance and the final model achieves improvements of 1.32 in LAS and 2.65 in BLEU score on these two tasks respectively over strong baselines and it outperforms the greedy structured prediction models in previous literatures.

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Proceedings of ACL 2018, Student Research Workshop
Vered Shwartz | Jeniya Tabassum | Rob Voigt | Wanxiang Che | Marie-Catherine de Marneffe | Malvina Nissim
Proceedings of ACL 2018, Student Research Workshop

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Chinese Grammatical Error Diagnosis using Statistical and Prior Knowledge driven Features with Probabilistic Ensemble Enhancement
Ruiji Fu | Zhengqi Pei | Jiefu Gong | Wei Song | Dechuan Teng | Wanxiang Che | Shijin Wang | Guoping Hu | Ting Liu
Proceedings of the 5th Workshop on Natural Language Processing Techniques for Educational Applications

This paper describes our system at NLPTEA-2018 Task #1: Chinese Grammatical Error Diagnosis. Grammatical Error Diagnosis is one of the most challenging NLP tasks, which is to locate grammar errors and tell error types. Our system is built on the model of bidirectional Long Short-Term Memory with a conditional random field layer (BiLSTM-CRF) but integrates with several new features. First, richer features are considered in the BiLSTM-CRF model; second, a probabilistic ensemble approach is adopted; third, Template Matcher are used during a post-processing to bring in human knowledge. In official evaluation, our system obtains the highest F1 scores at identifying error types and locating error positions, the second highest F1 score at sentence level error detection. We also recommend error corrections for specific error types and achieve the best F1 performance among all participants.

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An AMR Aligner Tuned by Transition-based Parser
Yijia Liu | Wanxiang Che | Bo Zheng | Bing Qin | Ting Liu
Proceedings of the 2018 Conference on Empirical Methods in Natural Language Processing

In this paper, we propose a new rich resource enhanced AMR aligner which produces multiple alignments and a new transition system for AMR parsing along with its oracle parser. Our aligner is further tuned by our oracle parser via picking the alignment that leads to the highest-scored achievable AMR graph. Experimental results show that our aligner outperforms the rule-based aligner in previous work by achieving higher alignment F1 score and consistently improving two open-sourced AMR parsers. Based on our aligner and transition system, we develop a transition-based AMR parser that parses a sentence into its AMR graph directly. An ensemble of our parsers with only words and POS tags as input leads to 68.4 Smatch F1 score, which outperforms the current state-of-the-art parser.

2017

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The HIT-SCIR System for End-to-End Parsing of Universal Dependencies
Wanxiang Che | Jiang Guo | Yuxuan Wang | Bo Zheng | Huaipeng Zhao | Yang Liu | Dechuan Teng | Ting Liu
Proceedings of the CoNLL 2017 Shared Task: Multilingual Parsing from Raw Text to Universal Dependencies

This paper describes our system (HIT-SCIR) for the CoNLL 2017 shared task: Multilingual Parsing from Raw Text to Universal Dependencies. Our system includes three pipelined components: tokenization, Part-of-Speech (POS) tagging and dependency parsing. We use character-based bidirectional long short-term memory (LSTM) networks for both tokenization and POS tagging. Afterwards, we employ a list-based transition-based algorithm for general non-projective parsing and present an improved Stack-LSTM-based architecture for representing each transition state and making predictions. Furthermore, to parse low/zero-resource languages and cross-domain data, we use a model transfer approach to make effective use of existing resources. We demonstrate substantial gains against the UDPipe baseline, with an average improvement of 3.76% in LAS of all languages. And finally, we rank the 4th place on the official test sets.

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Benben: A Chinese Intelligent Conversational Robot
Wei-Nan Zhang | Ting Liu | Bing Qin | Yu Zhang | Wanxiang Che | Yanyan Zhao | Xiao Ding
Proceedings of ACL 2017, System Demonstrations

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Transition-Based Disfluency Detection using LSTMs
Shaolei Wang | Wanxiang Che | Yue Zhang | Meishan Zhang | Ting Liu
Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing

In this paper, we model the problem of disfluency detection using a transition-based framework, which incrementally constructs and labels the disfluency chunk of input sentences using a new transition system without syntax information. Compared with sequence labeling methods, it can capture non-local chunk-level features; compared with joint parsing and disfluency detection methods, it is free for noise in syntax. Experiments show that our model achieves state-of-the-art f-score of 87.5% on the commonly used English Switchboard test set, and a set of in-house annotated Chinese data.

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Deep Learning in Lexical Analysis and Parsing
Wanxiang Che | Yue Zhang
Proceedings of the IJCNLP 2017, Tutorial Abstracts

Neural networks, also with a fancy name deep learning, just right can overcome the above “feature engineering” problem. In theory, they can use non-linear activation functions and multiple layers to automatically find useful features. The novel network structures, such as convolutional or recurrent, help to reduce the difficulty further. These deep learning models have been successfully used for lexical analysis and parsing. In this tutorial, we will give a review of each line of work, by contrasting them with traditional statistical methods, and organizing them in consistent orders.

2016

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Chinese Grammatical Error Diagnosis with Long Short-Term Memory Networks
Bo Zheng | Wanxiang Che | Jiang Guo | Ting Liu
Proceedings of the 3rd Workshop on Natural Language Processing Techniques for Educational Applications (NLPTEA2016)

Grammatical error diagnosis is an important task in natural language processing. This paper introduces our Chinese Grammatical Error Diagnosis (CGED) system in the NLP-TEA-3 shared task for CGED. The CGED system can diagnose four types of grammatical errors which are redundant words (R), missing words (M), bad word selection (S) and disordered words (W). We treat the CGED task as a sequence labeling task and describe three models, including a CRF-based model, an LSTM-based model and an ensemble model using stacking. We also show in details how we build and train the models. Evaluation includes three levels, which are detection level, identification level and position level. On the CGED-HSK dataset of NLP-TEA-3 shared task, our system presents the best F1-scores in all the three levels and also the best recall in the last two levels.

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A Universal Framework for Inductive Transfer Parsing across Multi-typed Treebanks
Jiang Guo | Wanxiang Che | Haifeng Wang | Ting Liu
Proceedings of COLING 2016, the 26th International Conference on Computational Linguistics: Technical Papers

Various treebanks have been released for dependency parsing. Despite that treebanks may belong to different languages or have different annotation schemes, they contain common syntactic knowledge that is potential to benefit each other. This paper presents a universal framework for transfer parsing across multi-typed treebanks with deep multi-task learning. We consider two kinds of treebanks as source: the multilingual universal treebanks and the monolingual heterogeneous treebanks. Knowledge across the source and target treebanks are effectively transferred through multi-level parameter sharing. Experiments on several benchmark datasets in various languages demonstrate that our approach can make effective use of arbitrary source treebanks to improve target parsing models.

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A Neural Attention Model for Disfluency Detection
Shaolei Wang | Wanxiang Che | Ting Liu
Proceedings of COLING 2016, the 26th International Conference on Computational Linguistics: Technical Papers

In this paper, we study the problem of disfluency detection using the encoder-decoder framework. We treat disfluency detection as a sequence-to-sequence problem and propose a neural attention-based model which can efficiently model the long-range dependencies between words and make the resulting sentence more likely to be grammatically correct. Our model firstly encode the source sentence with a bidirectional Long Short-Term Memory (BI-LSTM) and then use the neural attention as a pointer to select an ordered sub sequence of the input as the output. Experiments show that our model achieves the state-of-the-art f-score of 86.7% on the commonly used English Switchboard test set. We also evaluate the performance of our model on the in-house annotated Chinese data and achieve a significantly higher f-score compared to the baseline of CRF-based approach.

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A Unified Architecture for Semantic Role Labeling and Relation Classification
Jiang Guo | Wanxiang Che | Haifeng Wang | Ting Liu | Jun Xu
Proceedings of COLING 2016, the 26th International Conference on Computational Linguistics: Technical Papers

This paper describes a unified neural architecture for identifying and classifying multi-typed semantic relations between words in a sentence. We investigate two typical and well-studied tasks: semantic role labeling (SRL) which identifies the relations between predicates and arguments, and relation classification (RC) which focuses on the relation between two entities or nominals. While mostly studied separately in prior work, we show that the two tasks can be effectively connected and modeled using a general architecture. Experiments on CoNLL-2009 benchmark datasets show that our SRL models significantly outperform state-of-the-art approaches. Our RC models also yield competitive performance with the best published records. Furthermore, we show that the two tasks can be trained jointly with multi-task learning, resulting in additive significant improvements for SRL.

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SemEval-2016 Task 9: Chinese Semantic Dependency Parsing
Wanxiang Che | Yanqiu Shao | Ting Liu | Yu Ding
Proceedings of the 10th International Workshop on Semantic Evaluation (SemEval-2016)

2015

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Cross-lingual Dependency Parsing Based on Distributed Representations
Jiang Guo | Wanxiang Che | David Yarowsky | Haifeng Wang | Ting Liu
Proceedings of the 53rd Annual Meeting of the Association for Computational Linguistics and the 7th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)

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Transition-Based Syntactic Linearization
Yijia Liu | Yue Zhang | Wanxiang Che | Bing Qin
Proceedings of the 2015 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

2014

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Type-Supervised Domain Adaptation for Joint Segmentation and POS-Tagging
Meishan Zhang | Yue Zhang | Wanxiang Che | Ting Liu
Proceedings of the 14th Conference of the European Chapter of the Association for Computational Linguistics

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Learning Sense-specific Word Embeddings By Exploiting Bilingual Resources
Jiang Guo | Wanxiang Che | Haifeng Wang | Ting Liu
Proceedings of COLING 2014, the 25th International Conference on Computational Linguistics: Technical Papers

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Jointly or Separately: Which is Better for Parsing Heterogeneous Dependencies?
Meishan Zhang | Wanxiang Che | Yanqiu Shao | Ting Liu
Proceedings of COLING 2014, the 25th International Conference on Computational Linguistics: Technical Papers

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Sentence Compression for Target-Polarity Word Collocation Extraction
Yanyan Zhao | Wanxiang Che | Honglei Guo | Bing Qin | Zhong Su | Ting Liu
Proceedings of COLING 2014, the 25th International Conference on Computational Linguistics: Technical Papers

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Revisiting Embedding Features for Simple Semi-supervised Learning
Jiang Guo | Wanxiang Che | Haifeng Wang | Ting Liu
Proceedings of the 2014 Conference on Empirical Methods in Natural Language Processing (EMNLP)

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Domain Adaptation for CRF-based Chinese Word Segmentation using Free Annotations
Yijia Liu | Yue Zhang | Wanxiang Che | Ting Liu | Fan Wu
Proceedings of the 2014 Conference on Empirical Methods in Natural Language Processing (EMNLP)

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Learning Semantic Hierarchies via Word Embeddings
Ruiji Fu | Jiang Guo | Bing Qin | Wanxiang Che | Haifeng Wang | Ting Liu
Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

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Character-Level Chinese Dependency Parsing
Meishan Zhang | Yue Zhang | Wanxiang Che | Ting Liu
Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

2013

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Named Entity Recognition with Bilingual Constraints
Wanxiang Che | Mengqiu Wang | Christopher D. Manning | Ting Liu
Proceedings of the 2013 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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Chinese Parsing Exploiting Characters
Meishan Zhang | Yue Zhang | Wanxiang Che | Ting Liu
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

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Joint Word Alignment and Bilingual Named Entity Recognition Using Dual Decomposition
Mengqiu Wang | Wanxiang Che | Christopher D. Manning
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

2012

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SemEval-2012 Task 5: Chinese Semantic Dependency Parsing
Wanxiang Che | Meishan Zhang | Yanqiu Shao | Ting Liu
*SEM 2012: The First Joint Conference on Lexical and Computational Semantics – Volume 1: Proceedings of the main conference and the shared task, and Volume 2: Proceedings of the Sixth International Workshop on Semantic Evaluation (SemEval 2012)

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Micro blogs Oriented Word Segmentation System
Yijia Liu | Meishan Zhang | Wanxiang Che | Ting Liu | Yihe Deng
Proceedings of the Second CIPS-SIGHAN Joint Conference on Chinese Language Processing

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Multiple TreeBanks Integration for Chinese Phrase Structure Grammar Parsing Using Bagging
Meishan Zhang | Wanxiang Che | Ting Liu
Proceedings of the Second CIPS-SIGHAN Joint Conference on Chinese Language Processing

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A Separately Passive-Aggressive Training Algorithm for Joint POS Tagging and Dependency Parsing
Zhenghua Li | Min Zhang | Wanxiang Che | Ting Liu
Proceedings of COLING 2012

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Stacking Heterogeneous Joint Models of Chinese POS Tagging and Dependency Parsing
Meishan Zhang | Wanxiang Che | Ting Liu | Zhenghua Li
Proceedings of COLING 2012

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Exploiting Multiple Treebanks for Parsing with Quasi-synchronous Grammars
Zhenghua Li | Ting Liu | Wanxiang Che
Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

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A Comparison of Chinese Parsers for Stanford Dependencies
Wanxiang Che | Valentin Spitkovsky | Ting Liu
Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

2011

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Joint Models for Chinese POS Tagging and Dependency Parsing
Zhenghua Li | Min Zhang | Wanxiang Che | Ting Liu | Wenliang Chen | Haizhou Li
Proceedings of the 2011 Conference on Empirical Methods in Natural Language Processing

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A Graph-based Method for Entity Linking
Yuhang Guo | Wanxiang Che | Ting Liu | Sheng Li
Proceedings of 5th International Joint Conference on Natural Language Processing

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Improving Chinese POS Tagging with Dependency Parsing
Zhenghua Li | Wanxiang Che | Ting Liu
Proceedings of 5th International Joint Conference on Natural Language Processing

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Word Sense Disambiguation Corpora Acquisition via Confirmation Code
Wanxiang Che | Ting Liu
Proceedings of 5th International Joint Conference on Natural Language Processing

2010

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HIT-CIR: An Unsupervised WSD System Based on Domain Most Frequent Sense Estimation
Yuhang Guo | Wanxiang Che | Wei He | Ting Liu | Sheng Li
Proceedings of the 5th International Workshop on Semantic Evaluation

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Improving Semantic Role Labeling with Word Sense
Wanxiang Che | Ting Liu | Yongqiang Li
Human Language Technologies: The 2010 Annual Conference of the North American Chapter of the Association for Computational Linguistics

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Jointly Modeling WSD and SRL with Markov Logic
Wanxiang Che | Ting Liu
Proceedings of the 23rd International Conference on Computational Linguistics (Coling 2010)

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LTP: A Chinese Language Technology Platform
Wanxiang Che | Zhenghua Li | Ting Liu
Coling 2010: Demonstrations

2009

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Multilingual Dependency-based Syntactic and Semantic Parsing
Wanxiang Che | Zhenghua Li | Yongqiang Li | Yuhang Guo | Bing Qin | Ting Liu
Proceedings of the Thirteenth Conference on Computational Natural Language Learning (CoNLL 2009): Shared Task

2008

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A Cascaded Syntactic and Semantic Dependency Parsing System
Wanxiang Che | Zhenghua Li | Yuxuan Hu | Yongqiang Li | Bing Qin | Ting Liu | Sheng Li
CoNLL 2008: Proceedings of the Twelfth Conference on Computational Natural Language Learning

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Fast Computing Grammar-driven Convolution Tree Kernel for Semantic Role Labeling
Wanxiang Che | Min Zhang | Ai Ti Aw | Chew Lim Tan | Ting Liu | Sheng Li
Proceedings of the Third International Joint Conference on Natural Language Processing: Volume-II

2007

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HIT-IR-WSD: A WSD System for English Lexical Sample Task
Yuhang Guo | Wanxiang Che | Yuxuan Hu | Wei Zhang | Ting Liu
Proceedings of the Fourth International Workshop on Semantic Evaluations (SemEval-2007)

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A Grammar-driven Convolution Tree Kernel for Semantic Role Classification
Min Zhang | Wanxiang Che | Aiti Aw | Chew Lim Tan | Guodong Zhou | Ting Liu | Sheng Li
Proceedings of the 45th Annual Meeting of the Association of Computational Linguistics

2006

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A Hybrid Convolution Tree Kernel for Semantic Role Labeling
Wanxiang Che | Min Zhang | Ting Liu | Sheng Li
Proceedings of the COLING/ACL 2006 Main Conference Poster Sessions

2005

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Semantic Role Labeling System Using Maximum Entropy Classifier
Ting Liu | Wanxiang Che | Sheng Li | Yuxuan Hu | Huaijun Liu
Proceedings of the Ninth Conference on Computational Natural Language Learning (CoNLL-2005)

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Improved-Edit-Distance Kernel for Chinese Relation Extraction
Wanxiang Che | Jianmin Jiang | Zhong Su | Yue Pan | Ting Liu
Companion Volume to the Proceedings of Conference including Posters/Demos and tutorial abstracts

2004

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A New Chinese Natural Language Understanding Architecture Based on Multilayer Search Mechanism
Wanxiang Che | Ting Liu | Sheng Li
Proceedings of the Third SIGHAN Workshop on Chinese Language Processing

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