Publications

Preprints

Liu, Zexiang, Necmiye Ozay, Eduardo Sontag, “Properties of Immersions for Systems with Multiple Limit Sets with Implications to Learning Koopman Embeddings”, arXiv preprint arXiv:2312.17045 (2023)
Liu, Zexiang and Necmiye Ozay, “Quantifying the Value of Preview Information for Safety Control” arXiv preprint arXiv:2303.10660 (2023)

Journal Papers

Liu, Zexiang, Hao Chen, Yulong Gao, and Necmiye Ozay, “Opportunistic Safety Outside the Maximal Controlled Invariant Set”, IEEE Control Systems Letters, 2023 (website)
Anevlavis, Tzanis*, Zexiang Liu*, Necmiye Ozay, and Paulo Tabuada. “Controlled Invariant Sets: Implicit Closed-form Representations and Applications”, IEEE Transactions on Automatic Control (TAC), 2023.
Balim, Haldun, Antoine Aspeel, Zexiang Liu, and Necmiye Ozay, “Koopman-inspired Implicit Backward Reachable Sets for Unknown Nonlinear Systems”, IEEE Control Systems Letters, 2023.

Conference Papers

Liu, Zexiang, Necmiye Ozay, and Eduardo Sontag, “On the Non-Existence of Immersions for Systems with Multiple Omega-Limit Sets”, IFAC World Congress, Yokohoma, Japan, July 2023 (to appear)
Liu, Zexiang, and Necmiye Ozay. “On the Convergence of the Backward Reachable Sets of Robust Controlled Invariant Sets For Discrete-time Linear Systems.” Proc. 61th IEEE Conference on Decision and Control (CDC), Cancun, Mexico, December 2022.
Du, Zhe*, Zexiang Liu*, Jack Weitze, and Necmiye Ozay. “Sample Complexity Analysis and Self-regularization in Identification of Over-parameterized ARX Models.”, Proc. 61th IEEE Conference on Decision and Control (CDC), Cancun, Mexico, December 2022.
Li, Dan, Mohamad Louai Shehab, Zexiang Liu, Nikos Aréchiga, Jonathan DeCastro, and Necmiye Ozay. “Outlier-robust Inverse Reinforcement Learning and Reward-based Detection of Anomalous Driving Behaviors.” In 2022 IEEE 25th International Conference on Intelligent Transportation Systems (ITSC), pp. 4175-4182. IEEE, 2022.
Liu, Zexiang, Tzanis Anevlavis, Necmiye Ozay, and Paulo Tabuada. “Automaton-based implicit controlled invariant set computation for discrete-time linear systems.” In 2021 60th IEEE Conference on Decision and Control (CDC), pp. 1112-1119. IEEE, 2021.
Liu, Zexiang, and Necmiye Ozay. “On the value of preview information for safety control.” In 2021 American Control Conference (ACC), pp. 2348-2354. IEEE, 2021.
Anevlavis, Tzanis, Zexiang Liu, Necmiye Ozay, and Paulo Tabuada. “An enhanced hierarchy for (robust) controlled invariance.” In 2021 American Control Conference (ACC), pp. 4860-4865. IEEE, 2021.
Jiang, Minghao, Kristina Miller, Dawei Sun, Zexiang Liu, Yixuan Jia, Arnab Datta, Necmiye Ozay, and Sayan Mitra. “Continuous integration and testing for autonomous racing software: An experience report from graic.” In IEEE ICRA 2021, International Conference on Robotics and Automation, Workshop on OPPORTUNITIES AND CHALLENGES WITH AUTONOMOUS RACING. 2021.
Liu, Zexiang, and Necmiye Ozay. “Safe online planning in unknown nonconvex environments with implicit controlled invariant sets.” IFAC-PapersOnLine 54, no. 5 (2021): 163-168.
Arwashan, Michael, Tiancheng Ge, Zexiang Liu, and Necmiye Ozay. “Driving with guardian: Blending user inputs with safety ensuring barriers”, Proc. IEEE Conference on Control Technology and Applications (CCTA), Montreal, Canada, August 2020.
Liu, Zexiang, Liren Yang, and Necmiye Ozay. “Scalable Computation of Controlled Invariant Sets for Discrete-Time Linear Systems with Input Delays”, Proc. American Control Conference (ACC), Denver, CO, July 2020.
Liu, Zexiang, and Necmiye Ozay. “Safety control with preview automaton”, Proc. 58th IEEE Conference on Decision and Control (CDC), Nice, France, December 2019
Sahin, Yunus E., Zexiang Liu, Kwesi Rutledge, Dimitra Panagou, Sze Zheng Yong, and Necmiye Ozay. “Intention-Aware Supervisory Control with Driving Safety Applications”, Proc. IEEE Conference on Control Technology and Applications (CCTA), Hong Kong, China, August 2019.

Technical Reports

Liu, Zexiang, Necmiye Ozay, and Nicolas Perrin. “Warm-Starting Fixed-Point Based Control Synthesis”, University of Michigan, Department of Electrical Engineering and Computer Science, technical report, 2018.