# Lei Xu

> Machine Learning Engineer in AI X Security

Location: New York, New York, United States
Profile: https://flows.cv/leixu

## Work Experience
### Software Engineer, Machine Learning @ Instagram
Jan 2024 – Present | New York, United States
LLM for Instagram Trust and Safety

### Staff Machine Learning Engineer (Tech Lead) @ Abnormal Security
Jan 2020 – Jan 2024 | New York, New York
Build our core ML/AI email security product! Lead of general model team

### Research Engineer @ ASAPP
Jan 2018 – Jan 2019 | New York, New York
NLP, ML, AI, Healthcare | NYC based unicorn

### Teaching Assistant @ New York University
Jan 2017 – Jan 2018 | Greater New York City Area
Teaching fellow for Computer Science Department in Courant Institute of Mathematical Sciences graduate-level course 'Predictive Analytics'

TA for Center for Data Science in Courant Institute of Mathematical Sciences graduate-level course 'Introduction to Casual Inference for Data Scientist'

### Big Data Techinical Intern @ AT&T
Jan 2017 – Jan 2017 | Dallas/Fort Worth Area
1. Worked on post processing module for optical character recognition(OCR) result of AT&T contracts and predicted the best replacement for misspellings using natural language processing knowledge
2. Conducted error analysis with big data tools such as Pyspark, Hadoop and SolrUI in 4 million image-extracted text documents and discovered two major patterns in the misspellings
3. Reviewed existing solution
4. Designed process for tokenization with different ways and correction with Noisy Channel Model
5. Implemented word corrector using Python from scratch tailored for AT&T contracts, which increased Word Recognition Rate by 16% 
6. Created AT&T dictionary for NLP workers within the company

### Machine Learning Intern @ NYU Langone Health
Jan 2017 – Jan 2017 | Greater New York City Area
1. Explored ways of ensembling machine learning models to eliminate overfitting issue in existing osteoporosis classification model 
2. Worked on tuning model hyperparameter using cross-validation and Bayesian optimization with Keras


## Education
### Master of Science (M.S.) in data science
New York University

### Bachelor of Science (B.S.) in Statistics
East China Normal University

### CSC Outstanding Undergraduates Exchange Program in Statistics
Victoria University of Wellington

### Hefei No.1 High School


## Contact & Social
- LinkedIn: https://linkedin.com/in/leixu1005

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Source: https://flows.cv/leixu
JSON Resume: https://flows.cv/leixu/resume.json
Last updated: 2026-04-05