Xian Qian


2023

pdf bib
SESCORE2: Learning Text Generation Evaluation via Synthesizing Realistic Mistakes
Wenda Xu | Xian Qian | Mingxuan Wang | Lei Li | William Yang Wang
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Is it possible to train a general metric for evaluating text generation quality without human-annotated ratings? Existing learned metrics either perform unsatisfactory across text generation tasks or require human ratings for training on specific tasks. In this paper, we propose SEScore2, a self-supervised approach for training a model-based metric for text generation evaluation. The key concept is to synthesize realistic model mistakes by perturbing sentences retrieved from a corpus. We evaluate SEScore2 and previous methods on four text generation tasks across three languages. SEScore2 outperforms all prior unsupervised metrics on four text generation evaluation benchmarks, with an average Kendall improvement of 0.158. Surprisingly, SEScore2 even outperforms the supervised BLEURT and COMET on multiple text generation tasks.

2022

pdf bib
The VolcTrans System for WMT22 Multilingual Machine Translation Task
Xian Qian | Kai Hu | Jiaqiang Wang | Yifeng Liu | Xingyuan Pan | Jun Cao | Mingxuan Wang
Proceedings of the Seventh Conference on Machine Translation (WMT)

This report describes our VolcTrans system for the WMT22 shared task on large-scale multilingual machine translation. We participated in the unconstrained track which allows the use of external resources. Our system is a transformer-based multilingual model trained on data from multiple sources including the public training set from the data track, NLLB data provided by Meta AI, self-collected parallel corpora, and pseudo bitext from back-translation. Both bilingual and monolingual texts are cleaned by a series of heuristic rules. On the official test set, our system achieves 17.3 BLEU, 21.9 spBLEU, and 41.9 chrF2++ on average over all language pairs. Averaged inference speed is 11.5 sentences per second using a single Nvidia Tesla V100 GPU.

2017

pdf bib
A non-DNN Feature Engineering Approach to Dependency Parsing – FBAML at CoNLL 2017 Shared Task
Xian Qian | Yang Liu
Proceedings of the CoNLL 2017 Shared Task: Multilingual Parsing from Raw Text to Universal Dependencies

For this year’s multilingual dependency parsing shared task, we developed a pipeline system, which uses a variety of features for each of its components. Unlike the recent popular deep learning approaches that learn low dimensional dense features using non-linear classifier, our system uses structured linear classifiers to learn millions of sparse features. Specifically, we trained a linear classifier for sentence boundary prediction, linear chain conditional random fields (CRFs) for tokenization, part-of-speech tagging and morph analysis. A second order graph based parser learns the tree structure (without relations), and fa linear tree CRF then assigns relations to the dependencies in the tree. Our system achieves reasonable performance – 67.87% official averaged macro F1 score

2015

pdf bib
Feature Selection in Kernel Space: A Case Study on Dependency Parsing
Xian Qian | Yang 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)

2014

pdf bib
Polynomial Time Joint Structural Inference for Sentence Compression
Xian Qian | Yang Liu
Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

pdf bib
2-Slave Dual Decomposition for Generalized Higher Order CRFs
Xian Qian | Yang Liu
Transactions of the Association for Computational Linguistics, Volume 2

We show that the decoding problem in generalized Higher Order Conditional Random Fields (CRFs) can be decomposed into two parts: one is a tree labeling problem that can be solved in linear time using dynamic programming; the other is a supermodular quadratic pseudo-Boolean maximization problem, which can be solved in cubic time using a minimum cut algorithm. We use dual decomposition to force their agreement. Experimental results on Twitter named entity recognition and sentence dependency tagging tasks show that our method outperforms spanning tree based dual decomposition.

2013

pdf bib
Fast Joint Compression and Summarization via Graph Cuts
Xian Qian | Yang Liu
Proceedings of the 2013 Conference on Empirical Methods in Natural Language Processing

pdf bib
Disfluency Detection Using Multi-step Stacked Learning
Xian Qian | Yang Liu
Proceedings of the 2013 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

pdf bib
Branch and Bound Algorithm for Dependency Parsing with Non-local Features
Xian Qian | Yang Liu
Transactions of the Association for Computational Linguistics, Volume 1

Graph based dependency parsing is inefficient when handling non-local features due to high computational complexity of inference. In this paper, we proposed an exact and efficient decoding algorithm based on the Branch and Bound (B&B) framework where non-local features are bounded by a linear combination of local features. Dynamic programming is used to search the upper bound. Experiments are conducted on English PTB and Chinese CTB datasets. We achieved competitive Unlabeled Attachment Score (UAS) when no additional resources are available: 93.17% for English and 87.25% for Chinese. Parsing speed is 177 words per second for English and 97 words per second for Chinese. Our algorithm is general and can be adapted to non-projective dependency parsing or other graphical models.

pdf bib
Using Supervised Bigram-based ILP for Extractive Summarization
Chen Li | Xian Qian | Yang Liu
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

2012

pdf bib
A Two-step Approach to Sentence Compression of Spoken Utterances
Dong Wang | Xian Qian | Yang Liu
Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

pdf bib
Joint Chinese Word Segmentation, POS Tagging and Parsing
Xian Qian | Yang Liu
Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning

2010

pdf bib
Joint Training and Decoding Using Virtual Nodes for Cascaded Segmentation and Tagging Tasks
Xian Qian | Qi Zhang | Yaqian Zhou | Xuanjing Huang | Lide Wu
Proceedings of the 2010 Conference on Empirical Methods in Natural Language Processing

pdf bib
2D Trie for Fast Parsing
Xian Qian | Qi Zhang | Xuanjing Huang | Lide Wu
Proceedings of the 23rd International Conference on Computational Linguistics (Coling 2010)

2008

pdf bib
CRF-based Hybrid Model for Word Segmentation, NER and even POS Tagging
Zhiting Xu | Xian Qian | Yuejie Zhang | Yaqian Zhou
Proceedings of the Sixth SIGHAN Workshop on Chinese Language Processing