I am an Assistant Professor of Computer Science at George Mason University where I run the Robotic Anticipatory Intelligence & Learning (RAIL) Group. Our research, at the intersection of robotics and machine learning, is centered around developing representations that allow robots to better understand the impact of their actions, so that they may plan quickly and intelligently in a dynamic and uncertain world.
[NEW] We are developing 'railroad,' an open-source planning framework for concurrent multi-robot task planning under uncertainty that represents the unification of many of our lab's advances. Feel free to experiment with our learning-informed planning tool in a Colab notebook linked from our GitHub!
Recent and Highlighted News
Spring 2026 My lab graduated 4 PhD students this term! Congradulations to the new doctors: Dr. Abhishek Paudel, Dr. Abhish Khanal, Dr. Raihan Islam Arnob, and Dr. Hoang-Dung Bui (Bui co-advised by Erion Plaku).
March, 2026 I gave a talk at MIT’s Robotics Seminar Series. Here’s a recording of my talk:
My talk at MIT provides an excellent motivating introduction to our in-development multi-robot planning under uncertainty software package: railroad.
My talk at MIT provides an excellent motivating introduction to our in-development multi-robot planning under uncertainty software package: railroad.
May 2026 Our paper Why Do LLM-based Web Agents Fail? A Hierarchical Planning Perspective, by Mohamed Aghzal, Gregory J. Stein, and Ziyu Yao, has been accepted to the Annual Meeting of the Association for Computational Linguistics (acl) 2026.
Summer 2025 My lab is delighted to be hosting three high school summer student interns through the gmu assip program. Welcome all!
December 2024 I, as principal investigator, and gmu collaborators Daigo Shishika, Xuesu Xiao, and Xuan Wang have been awarded a $1.7 million grant from the US Army Research Lab’s Tactical Behaviors and Maneuvers program. Read more about through the gmu news announcement.
November 6, 2024 The rail Group had a busy Conference on Robot Learning (corl) 2024! First, my student Abhishek presentend a paper on multi-strategy domain adaptation for fast deployment-time improvement for navigation under uncertainty. Second, the lab presented a workshop paper at the Learning Effective Abstractions for Planning (leap) Workshop, at which I also gave an invited talk.
Roshan Dhakal, Duc M. Nguyen, Tom Silver, Xuesu Xiao, and Gregory J. Stein. “Anticipatory Task and Motion Planning: Improved Rearrangement in Persistent Continuous-Space Environments.” IEEE Robotics and Automation Letters (RA-L). 11(2), pp. 1850–1857. 2026. paper, ArXivshow bibtex
@article{dhakal2025anttamp,
title = {Anticipatory Task and Motion Planning: Improved
Rearrangement in Persistent Continuous-Space
Environments},
author = {Dhakal, Roshan and Nguyen, Duc M and
Silver, Tom and Xiao, Xuesu and
Stein, Gregory J.},
journal = {IEEE Robotics and Automation Letters},
volume = {11},
number = {2},
pages = {1850–1857},
year = {2026},
}
Abhish Khanal, Joseph Prince Mathew, Cameron Nowzari, Gregory J Stein. “Learning-Augmented Model-Based Multi-Robot Planning for Time-Critical Search and Inspection Under Uncertainty.” In: International Conference on Automation Science and Engineering (CASE). 2025. paper. show bibtex
@inproceedings{khanal2025mrsearch,
title = {Learning-Augmented Model-Based Multi-Robot
Planning for Time-Critical Search and
Inspection Under Uncertainty},
author = {Abhish Khanal and Joseph Prince Mathew and
Cameron Nowzari and Gregory J. Stein},
booktitle = {International Conference on Automation Science
and Engineering (CASE)},
pages = {969--975},
year = {2025},
}
Abhishek Paudel, Xuesu Xiao, and Gregory J. Stein. “Multi-Strategy Deployment-Time Learning and Adaptation for Navigation under Uncertainty.” In: Conference on Robot Learning (CoRL). 2024. paper, video. show bibtex
@inproceedings{paudel2024multistrategy,
author = {Abhishek Paudel and Xuesu Xiao and Gregory J. Stein},
title = {Multi-Strategy Deployment-Time Learning and Adaptation
for Navigation under Uncertainty},
booktitle = {Conference on Robot Learning (CoRL)},
year = {2024},
}
Raihan Islam Arnob and Gregory J. Stein. “Active Information Gathering for Long-Horizon Navigation Under Uncertainty by Learning the Value of Information.” In: International Conference on Intelligent Robots and Systems (IROS). 2024. paper, ArXiv. show bibtex
@inproceedings{arnob2024active,
author = {Raihan Islam Arnob and Gregory J. Stein},
title = {Active Information Gathering for Long-Horizon Navigation Under
Uncertainty by Learning the Value of Information},
booktitle = {International Conference on Intelligent Robots and Systems
(IROS)},
year = {2024},
}
Gregory J. Stein. “Generating High-Quality Explanations for Navigation in Partially-Revealed Environments.” In: Advances in Neural Information Processing Systems (NeurIPS). 2021. paper, talk (13 min), GitHub, blog post. show bibtex
@inproceedings{stein2021xailsp,
title = {Generating High-Quality Explanations for Navigation
in Partially-Revealed Environments},
author = {Gregory J. Stein},
booktitle = {Advances in Neural Information Processing Systems (NeurIPS)},
pages = {17493–17506},
year = {2021},
keywords = {explainability; planning under uncertainty;
subgoal-based planning; interpretable-by-design},
}
Christopher Bradley, Adam Pacheck, Gregory J. Stein, Sebastian Castro, Hadas Kress-Gazit, and Nicholas Roy. “Learning and Planning for Temporally Extended Tasks in Unknown Environments.” In: International Conference on Robotics and Automation (ICRA). 2021. paper, talk (3 min). show bibtex
@inproceedings{bradley2021potlp,
title = {Learning and Planning for Temporally Extended Tasks in Unknown
Environments},
author = {Christopher Bradley and Adam Pacheck and Gregory J. Stein and
Sebastian Castro and Hadas Kress-Gazit and Nicholas Roy},
booktitle = {International Conference on Robotics and Automation (ICRA)},
pages = {4830--4836},
year = {2021},
}
Gregory J. Stein, Christopher Bradley, and Nicholas Roy. “Learning over Subgoals for Efficient Navigation of Structured, Unknown Environments”. In: Conference on Robot Learning (CoRL). 2018. paper, talk (14 min). show bibtex
@inproceedings{stein2018subgoal,
author = {Stein, Gregory J. and Bradley, Christopher and Roy, Nicholas},
title = {Learning over Subgoals for Efficient Navigation of Structured,
Unknown Environments},
booktitle = {Conference on Robot Learning (CoRL)},
pages = {213--222},
year = {2018},
}
Best Paper Finalist at CoRL 2018; Best Oral Presentation at CoRL 2018.
Best Paper Finalist at CoRL 2018; Best Oral Presentation at CoRL 2018.
[Communication & Learning] Why have meetings with my advisor? This document gives an overview of how I think about when and how often my PhD students need to meet with me and what the substance of those meetings should be.
[Workflow & Process] A proof-of-concept for automated running of experiments and automatically including results and statistics in a LaTeX PDF via Make.
[Research] We improve reliable, long-horizon, goal-directed navigation in partially-mapped environments by using non- locally available information to predict the goodness of temporally-extended actions that enter unseen space.
[Research] We present a fast and reliable policy selection approach for navigation in partial maps that leverages information collected during deployment to introspect the behavior of alternative policies without deployment.
[Communication & Learning] I recently asked my students to prep Pecha Kucha-style presentations—18 slides that auto-advance every 20 seconds—and then told them to present each other’s slides, a fun and fantastic (if chaotic) way to improve slide quality.
[Workflow & Process] This guide aims to outline my strategies to encourage idea generation, essential for long-term research progress, through a habit of regular writing.
[Workflow & Process] Even research code benefits greatly from automated testing. My approach to getting started: if you need to write additional code to verify that some functionality is working, that additional code should be written as a test.
[Research] We generate explanations of a robot agent’s behavior as it navigates through a partially-revealed environment, expressed in terms of changes to its predictions about what lies in unseen space. Blog post accompanying our NeurIPS 2021 paper.
[Workflow & Process] I’ve started to think of expectation management as a part of self-care, and I try to think of myself as an other. As such, I try to underpromise and overdeliver to my future self.
[Workflow & Process] I try to make sure that my tasks are both easy to start making progress towards and have clear completion criteria, essential criteria for making sure they get done.
[Communication & Learning] Looking at the in-development work of others pulls back the curtain and reveals insight into the thought process of other researchers. Reviews are a largely-untapped pedagogical resource.
[Workflow & Process] All code in my research group is run exclusively inside Docker containers, helping us develop more quickly and share code with ease.
[Communication & Learning] One communication pitfall I often see is that many researchers will take figures from their papers and paste them into their slides. Here, I provide some tips for tailoring your figures to talks.
[Research] Using DeepMind’s AlphaZero AI to solve real problems will require a change in the way computers represent and think about the world. In this post, we discuss how abstract models of the world can be used for better AI decision making and discuss recent work of ours that proposes such a model for the task of navigation.