Current Research

TL;DR: I develop optimization theory. I apply them to socio-technical systems (e.g., various supply chains).

I focus on robust optimization, including dynamic and bilevel problems, driven by real-world challenges in transportation safety, supply chain resiliency, and broader areas like policy design and intelligent decision-making in high-stakes environments. My goal is to develop models and algorithms that are both practically useful and theoretically sound, with an emphasis on aesthetics and generalizability.

For prospective PhD students: If you have a strong background in optimization or machine learning, and want to apply cutting edge methods to new problems in supply chain and transportation, you can reach out to me.

In Preparation

• Robust Path (with Hao Hao)
• Last-Mile Delivery with Guarantees (with Yidi Miao, Eojin Han)
• Learning by Doing Different Gigs: Uncovering Freelancer Skill Development in Online Labor Markets (with Hai Wang and Guanting Wu)
• Assessing and Explaining Urban Transportation Network Efficiency (with Hao Hao and Hai Wang)
• Optimizing School Bus Pickups with Third-Party Coordination and Delay Prediction (with Neha, Holly Wiberg)
• Data-Driven Contract Design (with Eli Ben-Michael)
• The City of Dakar Reveals Traffic Crash Hotspots and Optimizes Emergency Dispatching (with Bintou Mbathie, Mor Diao, Mark Brennan, and Babacar Mbaye Ndiaye)
• Improving Basic Retail Coverage in Africa: Modeling Geographic Disadvantage Among Farmers in Senegal (with Mark Brennan, Steve Graves, Babacar Mbaye Ndiaye et al)
• Cost and Emissions Tradeoffs for a Decarbonization Hydrogen Aviation Supply Chain (with Jaih Hunter-Hill)
• Price of Fairness Under Uncertainty (with Philippe Blaettchen and Chengxin Yan)

Under Review

• Approximating Multiple Robust Optimization Solutions in a Single Pass (with Hao Hao) | paper
• Redefining Coherent Risk Measure: From Gauge Set to Regularization (with Ningji Wei and Xian Yu) | paper
• Fair Optimization of Mobility Subsidies in Multimodal Transportation Networks (with Lindsay Graff, Sean Qian, Katherine Flanigan)
• Teaching Applied Optimization with Large Language Models | paper
• Optimal Probabilistic Feature Shifts for Reclassification in Tree Ensembles (with Víctor Blanco, Alberto Japón, and Justo Puerto) | paper
• Enhancing Spatial-Temporal Demand Prediction In Transportation Systems Through Region Generation Using Soft Clustering (with Kyoungok Kim) | paper
• Geospatial Analytic Framework for Modeling Energy Savings of Truck-Drone Hybrid Last-Mile Delivery in Arbitrary Cities (with Seung Gyu Baik, Steven Willits, and Sebastian Scherer)
• OPTIMA: Optimized Policy for Intelligent Multi-Agent Systems Enables Coordination-Aware Autonomous Vehicles (with Rui Du, Kai Zhao, Jinlong Hou, and Qiang Zhang) | paper
• Information Basis in Dynamic Robust Optimization (with Ningji Wei)
• Distributionally Robust Principal-Agent Problems and Optimality of Contract Menus | paper
• A Mathematical Programming Approach to Optimal Classification Forests (with Víctor Blanco, Alberto Japón, and Justo Puerto) | paper
• Structural Properties of Equitable Solutions (book with Özgün Elçi and John Hooker)

Publications

1. Adjustability in Robust Linear Optimization (with Ningji Wei), Mathematical Programming (2024), paper
• First place, INFORMS Junior Faculty Forum Paper Competition (2022)
2. Being emotionally supportive: exploring the value of emotional appeals retargeting in recovering consumers of FinTech services. (with Tian Lu, Xianghua Lu, Hui Yang). Production and Operations Management (2024) , paper
3. Travel Cadence and Epidemic Spread, Proceedings of the Winter Simulation Conference (2021) (with Lauren Streitmatter) GitHub.
4. Fleet Sizing and Allocation for On-demand Last-Mile Transportation Systems, Transportation Research Part C. (joint work with Karmel Shehadeh and Hai Wang)
5. Designing response supply chain against bioattacks, Operations Research. (joint work with David Simchi-Levi and Nikos Trichakis)
• INFORMS Koopman Prize (2020)
• POMS HOCM best paper competition runner-up (2018)
• POMS SCM student paper competition runner-up (2017)
• MSOM SIG (2017)
6. Identifying risks and mitigating disruptions in the automotive supply chain. INFORMS Journal on Applied Analytics. (joint work with David Simchi-Levi, William Schmidt, Yehua Wei, and Ford Motor Company)
   • Ford Engineering Excellence Award (2015)
   • INFORMS Daniel H. Wagner Prize for Excellence in Operations Research Practice (2014)
7. Multi-stage resource-aware scheduling for data centers with heterogenous servers. Journal of Scheduling. (joint work with Tony Tran, Heyse Li, Doug Down, and Chris Beck)
8. Solving wind farm layout optimization with mixed integer programs and constraint programs. EURO Journal on Computational Optimization. (joint work with David Romero, Chris Beck, and Cristina Amon)
9. Multiobjective wind farm layout optimization with non-dominated sorting genetic algorithm. Journal of Mechanical Design. (joint work with Penelope Kwong, David Romero, Joaquin Moran, M. Morgenroth, and Cristina Amon)
10. A new mathematical programming approach to optimizing wind farm layouts. Renewable Energy. (joint work with Sarina Turner, David Romero, and Timothy Chan)

Datasets

• U.S. Household Commuting Dataset and Transportation Fairness (with Hao Hao and Hai Wang) | GitHub

Not Peer Reviewed

1. A Pathway to the Fuel of the Future: Hydrogen’s Role in Aviation Decarbonization | Student team: Jon Gordon, Jaih Hunter-Hill, Anna Cobb, Xiaohan Wu, Dorothy Li | Co-advisor: Jared Cohon
• Finalist at NASA 2023 Gateways to Blue Skies: Clean Aviation Energy (Blue Skies) Competition
2. Joint Optimization of School Bus Routes and Last-mile Services | Summary | Full report.
3. The New COVID-19 Variant Prediction with Dynamic Model - A policy memo to the Government of Republic of Indonesia (July 25, 2021) | GitHub.
4. Data-Driven Reopening Strategies for State and Local Governments. Report and slides on this CMU-wide collaboration. Cited in:
• Mitigating Economic Impact of the COVID-19 Pandemic and Preserving U.S. Strategic Competitiveness in Artificial Intelligence, National Security Commission on Artificial Intelligence.
• Process to Reopen Pennsylvania (May 12, 2020) Pennsylvania Governor's Office.

Academic Mentorship

Postdoc:

• Ningji Wei (2020 -- 2022). Current position: Assistant Professor at Texas Tech University.
• Alberto Japón Sáez (2022 -- 2023)

PhD:

• Hao Hao (2021 -- )
• Recipient of the TCS Presidential Fellowship at Carnegie Mellon University (2023)
• Guanting Wu (2022 -- )
• Yidi Miao (2023 -- )