Wei Xu     

[phonetic pronunciation: way shoo ]

Assistant Professor
School of Interactive Computing
Georgia Institute of Technology
  @cocoweixu      @cocoxu

My research lies at the intersections of machine learning, natural language processing, and social media. I focus on designing algorithms for learning semantics from large data for natural language understanding, and natural language generation in particular with stylistic variations. I recently received the NSF CRII Award, Criteo Faculty Research Award, CrowdFlower AI for Everyone Award, Best Paper Award at COLING'18, as well as research funds from DARPA. I was a postdoctoral researcher at the University of Pennsylvania. I received my PhD in Computer Science from New York University, MS and BS from Tsinghua University.

I am a senior area chair for NAACL 2022 (machine learning for NLP), 2021 (generation), and ACL 2020 (generation), and an area chair for EMNLP 2021 (computational social science), EMNLP 2020 (generation), AAAI 2020 (NLP), ACL 2019 (semantics), NAACL 2019 (generation), EMNLP 2018 (social media), COLING 2018 (semantics), EMNLP 2016 (generation), a workshop chair for ACL 2017, and the publicity chair for EMNLP 2019, NAACL 2018 and 2016. I also created a new undergraduate course on Social Media and Text Analytics.

  I'm recruiting 2-3 new PhD students this year (apply to PhD program and list me as a potential advisor). I also advise undergraduate and MS students with research thesis option (apply to MSCS program and email me).
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Research Highlights

Natural Language Generation / Stylistics

Many text-to-text generation problems can be thought of as sentential paraphrasing or monolingual machine translation. It faces an exponential search space larger than bilingual translation, but a much smaller optimal solution space due to specific task requirements. I am interested in a variety of generation problems, including style transfer [COLING'12] and stylistics in general (e.g., historic ↔ modern, non-standard ↔ standard [BUCC'13], feminine ↔ masculine [AAAI'16]). Our latest work focuses on controllable text generation [NAACL'21]. My work uncovered multiple serious problems in previous research (from 2010 to 2014) on text simplification [TACL'15] , designed a new tunable metric SARI [TACL'16] which is effective for evaluation and as a learning objective for training (now added to TensorFlow by the Google AI group), optimized syntax-based machine translation models [TACL'16], created pairwise neural ranking models to for lexical simplification [EMNLP'18], and studied document-level simplification [AAAI'20]. Our newest Transformer-based model initialized with BERT is the current state-of-the-art for automatic text simplification [ACL'20a].

Natural Language Understanding / Semantics

My approach to natural language understanding is learning and modeling paraphrases on a much larger scale and with a much broader range than previous work, essentially by developing more robust machine learning models and leveraging social media data. These paraphrase can enable natural language systems to handle errors (e.g., “everytime” ↔ “every time”), lexical variations (e.g., “oscar nom’d doc” ↔ “Oscar-nominated documentary”), rare words (e.g “NetsBulls series” ↔ “Nets and Bulls games”), and language shifts (e.g. “is bananas” ↔ “is great”). We designed a series of unsupervised and supervised learning approaches for paraphrase identification in social media data (also applicable to question/answer pairs for QA systems), ranging from neural network models [COLING'18][NAACL'18a] to multi-instance learning [TACL'14][EMNLP'16], and crowdsourcing large-scale datasets [SemEval'15][EMNLP'17].

Noisy User-generated Data / Social Media

For AI to truly understand human language and help people (e.g., instructing a robot), we ought to study the language people actually use in their daily life (e.g., posting on social media), besides the formally written texts that are well supported by existing NLP software. I thus focus on specially designed learning algorithms and the data for training these algorithms to develop tools to process and analyze noisy user-generated data. I have worked a lot with Twitter data [EMNLP'19][EMNLP'17][EMNLP'16] [TACL'14], given its importance and large scale coverage. Social media also contains very diverse languages for studying stylistics and semantics, carrying information that is important for both people’s everyday lives and national security. In the past three years, with my students, I have expanded my scope to cover a wider range of user-generated data, including biology lab protocols [NAACL'18b], GitHub, and StackOverflow [ACL'20b].


Group outings in 2021 with social distance.

Current Students:
    Mounica Maddela (PhD student, autumn 2017 -- ; generation/ranking EMNLP'21 NAACL'21 ACL'19 EMNLP'18)
    Chao Jiang (PhD student, autumn 2018 -- ; semantics/crosslingual ACL'21 ACL'20a NAACL'18)
    Yao Dou (PhD student, autumn 2021 -- ; generation AAAI'21)
    Jonathan Zheng (Undergrad, autumn 2020 -- ; social media)
    David Heineman (Undergrad, winter 2020 -- ; user interface/generation)
    Michael Ryan (Undergrad, winter 2020 -- ; text simplification)
    Dylan Small (Undergrad, autumn 2021 -- ; generation)
    Vishnu Suresh (Undergrad, autumn 2021 -- ; medical NLP)
    Elizabeth Liu (Undergrad, spring 2022 -- )
    Marcus Ma (Undergrad, spring 2022 -- )
    Alexandra Soong (Undergrad, spring 2022 -- )
    Jonathan Zhou (Undergrad, spring 2022 -- )
    Srushti Nandu (Research intern, summer 2021 -- ; social media)
    Andrew Duffy (Research intern, summer 2021 -- ; linguistic annotation)

PhD Thesis Committee:
    Yuval Pinter (PhD @GaTech, 2021; interpretability/semantics/morphology - advisor: Jacob Eisenstein)
    Sanqiang Zhao (PhD @UPitt, 2021; text simplification - advisor: Daqing He)
    Kai Cao (PhD @NYU, 2017; information extraction - advisor: Ralph Grishman)
    Maria Pershina (PhD @NYU, 2014; information extraction ACL'14 - advisor: Ralph Grishman)

Former Student Advisees:
    Wuwei Lan (PhD @OSU, 2021; semantics ACL'21 EMNLP'20'17 COLING'18 NAACL'18 → applied scientist Amazon)
    Jeniya Tabassum (PhD @OSU, 2021; social media ACL'20 EMNLP'16 - co-advisor: Alan Ritter → lecturer at OSU)
    Chaitanya Kulkarni (PhD @OSU; biology protocols NAACL'18b - advisor: Raghu Machiraju)
    Yang Zhong (MS @OSU, 2021; stylistics EMNLP-F'21 AAAI'20 → phd at UPitt)
    Mingkun Gao (MS @UPenn; crowdsourcing/MT NAACL'15 - advisor: Chris Callison-Burch → phd at UIUC)
    Siyu Qiu (MS @UPenn; semantics EMNLP'17 → Hulu)
    Piyush Ghai (MS @OSU; semantics → Amazon)
    Daniel Joongwon Kim (Undergrad @UPenn; generation EMNLP'21 - advisor: Chris Callison-Burch)
    Sydney Lee (Undergrad @OSU; linguistic annotation WNUT'20 → Capital One)
    Jim Chen (Undergrad @UPenn; crowdsourcing HCOMP'14 TACL'16 - advisor: Chris Callison-Burch → phd at UW)
    Ray Lei (Undergrad @UPenn; crowdsourcing HCOMP'14 → Microsoft)
    Wenchao Du (Undergrad @UWaterloo; dialog AAAI'17 SAP - advisor: Pascal Poupart → MS at CMU LTI)
    Sam Stevens (Undergrad @OSU; scientific writing → phd at OSU)
    Ema Goh (Undergrad; text simplification)
    Brian Seeds (Undergrad; user interface)
    Daniel Szoke (Undergrad; offensive language)
    Sarah Flanagan (Undergrad; linguistic annotation)
    Kenneth Koepcke (Undergrad; linguistic annotation)
    Panya Bhinder (High school intern, summer 2020 → CS undergrad at Georgia Tech)
    Solomon Wood (High school intern, spring 2020)

Professional Service
Senior Area Chair:    NAACL (2022), NAACL (2021), ACL (2020)
Area Chair:   EMNLP (2021, 2020, 2018, 2016), ACL (2019), AAAI (2020), NAACL (2019), COLING (2018)
Workshop Chair:   ACL (2017)
Publicity Chair:   EMNLP (2019), NAACL (2018, 2016)
     - Workshop on Natural Language Generation, Evaluation, and Metrics (GEM) at ACL 2021
     - Workshop on Noisy User-generated Text (W-NUT) at ACL 2015, COLING 2016, EMNLP 2017, 2018, 2019, 2020
     - SemEval 2015 shared-task: Paraphrases and Semantic Similarity in Twitter
     - 2016 Mid-Atlantic Student Colloquium on Speech, Language and Learning
Program Committee:
     ACL (2021, 2018, 2017, 2015, 2014, 2013), NAACL (2018, 2015), EMNLP (2017, 2016, 2015, 2014)
     WWW (2016, 2015), COLING (2016, 2014), AAAI (2016, 2015, 2012), KDD (2015)
Journal Reviewer:
     Transactions of the Association for Computational Linguistics (TACL)
     Journal of Artificial Intelligence Research (JAIR)

Invited Talks

When I have spare time, I enjoy visiting art museums, hiking, biking, and snowboarding.

I wrote a biography of my phd advisor Ralph Grishman along with some early history of Information Extraction research in 2017.

I also made a list of the best dressed NLP researchers in 2016/17 , 2015 and 2014.