Wen Li


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LZ1904 at SemEval-2021 Task 5: Bi-LSTM-CRF for Toxic Span Detection using Pretrained Word Embedding
Liang Zou | Wen Li
Proceedings of the 15th International Workshop on Semantic Evaluation (SemEval-2021)

Recurrent Neural Networks (RNN) have been widely used in various Natural Language Processing (NLP) tasks such as text classification, sequence tagging, and machine translation. Long Short Term Memory (LSTM), a special unit of RNN, has the benefit of memorizing past and even future information in a sentence (especially for bidirectional LSTM). In the shared task of detecting spans which make texts toxic, we first apply pretrained word embedding (GloVe) to generate the word vectors after tokenization. And then we construct Bidirectional Long Short Term Memory-Conditional Random Field (Bi-LSTM-CRF) model by Baidu research to predict whether each word in the sentence is toxic or not. We tune hyperparameters of dropout rate, number of LSTM units, embedding size with 10 epochs and choose the best epoch with validation recall. Our model achieves an F1 score of 66.99 percent in test dataset.


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Ensemble Methods to Distinguish Mainland and Taiwan Chinese
Hai Hu | Wen Li | He Zhou | Zuoyu Tian | Yiwen Zhang | Liang Zou
Proceedings of the Sixth Workshop on NLP for Similar Languages, Varieties and Dialects

This paper describes the IUCL system at VarDial 2019 evaluation campaign for the task of discriminating between Mainland and Taiwan variation of mandarin Chinese. We first build several base classifiers, including a Naive Bayes classifier with word n-gram as features, SVMs with both character and syntactic features, and neural networks with pre-trained character/word embeddings. Then we adopt ensemble methods to combine output from base classifiers to make final predictions. Our ensemble models achieve the highest F1 score (0.893) in simplified Chinese track and the second highest (0.901) in traditional Chinese track. Our results demonstrate the effectiveness and robustness of the ensemble methods.

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NULI at SemEval-2019 Task 6: Transfer Learning for Offensive Language Detection using Bidirectional Transformers
Ping Liu | Wen Li | Liang Zou
Proceedings of the 13th International Workshop on Semantic Evaluation

Transfer learning and domain adaptive learning have been applied to various fields including computer vision (e.g., image recognition) and natural language processing (e.g., text classification). One of the benefits of transfer learning is to learn effectively and efficiently from limited labeled data with a pre-trained model. In the shared task of identifying and categorizing offensive language in social media, we preprocess the dataset according to the language behaviors on social media, and then adapt and fine-tune the Bidirectional Encoder Representation from Transformer (BERT) pre-trained by Google AI Language team. Our team NULI wins the first place (1st) in Sub-task A - Offensive Language Identification and is ranked 4th and 18th in Sub-task B - Automatic Categorization of Offense Types and Sub-task C - Offense Target Identification respectively.


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Detecting Syntactic Features of Translated Chinese
Hai Hu | Wen Li | Sandra Kübler
Proceedings of the Second Workshop on Stylistic Variation

We present a machine learning approach to distinguish texts translated to Chinese (by humans) from texts originally written in Chinese, with a focus on a wide range of syntactic features. Using Support Vector Machines (SVMs) as classifier on a genre-balanced corpus in translation studies of Chinese, we find that constituent parse trees and dependency triples as features without lexical information perform very well on the task, with an F-measure above 90%, close to the results of lexical n-gram features, without the risk of learning topic information rather than translation features. Thus, we claim syntactic features alone can accurately distinguish translated from original Chinese. Translated Chinese exhibits an increased use of determiners, subject position pronouns, NP + “的” as NP modifiers, multiple NPs or VPs conjoined by "、", among other structures. We also interpret the syntactic features with reference to previous translation studies in Chinese, particularly the usage of pronouns.


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Gender Prediction for Chinese Social Media Data
Wen Li | Markus Dickinson
Proceedings of the International Conference Recent Advances in Natural Language Processing, RANLP 2017

Social media provides users a platform to publish messages and socialize with others, and microblogs have gained more users than ever in recent years. With such usage, user profiling is a popular task in computational linguistics and text mining. Different approaches have been used to predict users’ gender, age, and other information, but most of this work has been done on English and other Western languages. The goal of this project is to predict the gender of users based on their posts on Weibo, a Chinese micro-blogging platform. Given issues in Chinese word segmentation, we explore character and word n-grams as features for this task, as well as using character and word embeddings for classification. Given how the data is extracted, we approach the task on a per-post basis, and we show the difficulties of the task for both humans and computers. Nonetheless, we present encouraging results and point to future improvements.

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Classifier Stacking for Native Language Identification
Wen Li | Liang Zou
Proceedings of the 12th Workshop on Innovative Use of NLP for Building Educational Applications

This paper reports our contribution (team WLZ) to the NLI Shared Task 2017 (essay track). We first extract lexical and syntactic features from the essays, perform feature weighting and selection, and train linear support vector machine (SVM) classifiers each on an individual feature type. The output of base classifiers, as probabilities for each class, are then fed into a multilayer perceptron to predict the native language of the author. We also report the performance of each feature type, as well as the best features of a type. Our system achieves an accuracy of 86.55%, which is among the best performing systems of this shared task.


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IUCL at SemEval-2016 Task 6: An Ensemble Model for Stance Detection in Twitter
Can Liu | Wen Li | Bradford Demarest | Yue Chen | Sara Couture | Daniel Dakota | Nikita Haduong | Noah Kaufman | Andrew Lamont | Manan Pancholi | Kenneth Steimel | Sandra Kübler
Proceedings of the 10th International Workshop on Semantic Evaluation (SemEval-2016)


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“My Curiosity was Satisfied, but not in a Good Way”: Predicting User Ratings for Online Recipes
Can Liu | Chun Guo | Daniel Dakota | Sridhar Rajagopalan | Wen Li | Sandra Kübler | Ning Yu
Proceedings of the Second Workshop on Natural Language Processing for Social Media (SocialNLP)