Zekun Xu bio photo

Zekun Xu

Applied Scientist at Amazon

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Projects

Overview

Latent State Models for Personalized Medicine

  • Propose a partially observable Markov decision process framework that recommends personalized treatment for maximizing patient outcome.

  • Study asymptotics and causal inference in Q-Learning and V-learning with functional approximation.

Hidden Markov Models for Longitudinal Accelerometer Data

  • Develop a gradient-based estimation and inference for hierarchical hidden Markov model on zero-inflated count data.

  • Apply the methodology on clinical accelerometer data for arthritic cat and human physical activity.

Two Sigma: Using News to Predict Stock Movement

  •  Leverage news and market information to predict stock movement using neural network, random forest and gradient boosting tree. (Top 7% on Kaggle)

Data mining with the Truven Health Insurance Claim Database

  •  Build a propensity-score matched logistic regression to identify risk factors associated with fracture nonunion in the highly unbalanced population of surgical and nonsurgical patients.

  •  Implement multiple imputation methods for missing data.