Research

VeriVital People: Collaborators and Students

Research Interests

  • Cyber-physical systems: real-time, networked embedded control systems and software
  • Hybrid systems and distributed systems
  • Software engineering, formal methods, and formal verification
  • Reliability and fault-tolerance
  • Application areas including transportation systems (aerospace and automotive), robotics, power and energy

Research Support

We gratefully acknowledge the support of our ongoing/past research by AFOSR, AFRL, ARO, NSF (CISE CCF/SHF, CNS/CPS; ENG ECCS/EPCN), NVIDIA, ONR, Toyota Technical Center, and USDOT. More details on the projects are available in my CV.

Active & Ongoing Research Projects

Past & Completed Research Projects

  • "Reusable Formal Verification for Cyber-Physical Systems," Air Force Office of Scientific Research (AFOSR), Young Investigator Program (YIP), 2016-2017, Award Number: W911NF-16-1-0534, Role: Sole PI.
  • "Safely and Securely Controlling Large Swarms of Unmanned Aerial Vehicles (UAVs) with the STAbilizing Robot Language (StarL)," Wright Brothers Institute (WBI) Summer of Innovation, Wright-Patterson Air Force Base (WPAFB), Aerospace Systems Directorate (AFRL/RQ), Air Force Research Laboratory (AFRL), May 2017 to August 2017, Award Number: FA8650-12- 3-7255, Role: Sole PI
  • "Testbed Acquisition for Resilient Self-Organizing Microgrids," Defense University Research Instrumentation Program (DURIP), Office of Naval Research (ONR), September 2016 to September 2017, Award Number: N0014-16-1-3180, Role: Co-PI, with PI Ali Davoudi and Co-PIs Frank Lewis and Hamidreza Modares
  • "Realizing Resilient Self-Organizing Microgrids," Department of Defense (DoD) Research and Education Program for Historically Black Colleges and Universities and Minority-Serving Institutions (HBCU/MI), Army Research Office (ARO), September 2016 to September 2017, Award Number: N0014-16-1-3180, Role: Co-PI, with PI Ali Davoudi and Co-PIs Frank Lewis and Hamidreza Modares
  • "Formal Modeling of Emergence in Distributed Cyber-Physical Systems," Air Force Research Laboratory (AFRL), Trusted Autonomy and Verification and Validation (V&V), Integrated Command and Control, BAA-10-01-RIKA, 2015-2017, Award Number: FA8750-15-1-0105, Role: Sole PI
  • "App-Based Crowd Sourcing of Bicycle and Pedestrian Conflict Data," University Transportation Center for Livable Communities (TRCLC), US Department of Transportation (USDOT), 2015-2016, Role: Co-PI, with PI Stephen Mattingly and Co-PI Colleen Casey.

Program Committees and Conference Organization

Research Links

Software and Tools

We develop a large amount of research software, particularly verification tool prototypes. Some code is available on my Bitbucket account and the Verivital Bitbucket account, with limited developed on the Verivital GitHub account. Particular tools are:

Publications

Journal Articles (13)

2018
[J13], , , "Robust Exponential Stability and Disturbance Attenuation for Discrete-Time Switched Systems under Arbitrary Switching", In IEEE Transactions on Automatic Control (TAC), 2018, May. [bibtex] [pdf] [doi]
[J12], , , , , "Cyber-Physical Specification Mismatches", In ACM Transactions on Cyber-Physical Systems (TCPS), 2018. [bibtex] [pdf]
2017
[J11], , , , , , "Hybrid automata: from verification to implementation", In Software Tools for Technology Transfer (STTT), Springer, vol. , , pp. , 2017, August. [abstract] [software / source code] [bibtex] [pdf] [doi] [cites]
[J10], , , , "Model Validation of PWM DC-DC Converters", In IEEE Transactions on Industrial Electronics. (TIE), Institute of Electrical and Electronics Engineers (IEEE), 2017, June. [bibtex] [pdf] [doi]
[J9], "Event-triggered control for continuous-time switched linear systems", In IET Control Theory and Applications, Institution of Engineering and Technology, 2017, February. [abstract] [bibtex] [pdf] [doi]
[J8], , , "Detection of False-data Injection Attacks in Cyber-Physical DC Microgrids", In IEEE Transactions on Industrial Informatics, vol. , no. , pp. , 2017, . [abstract] [bibtex] [pdf] [doi]
[J7], , , "Output Reachable Set Estimation for Switched Linear Systems and Its Application in Safety Verification", In IEEE Transactions on Automatic Control (TAC), 2017. [bibtex] [pdf] [doi]
[J6], , , , "Order-reduction abstractions for safety verification of high-dimensional linear systems", In Discrete Event Dynamic Systems (DEDS), 2017. [bibtex] [pdf] [doi]
2016
[J5], , , , , , , , "Guided Search for Hybrid Systems Based on Coarse-Grained Space Abstractions", In Software Tools for Technology Transfer (STTT), Springer, vol. 18, , pp. , 2016, August. [abstract] [software / source code] [bibtex] [pdf] [doi] [cites]
[J4], , , , "Real-Time Reachability for Verified Simplex Design", In ACM Transactions on Embedded Computing Systems (TECS), ACM, vol. 15, no. 2, New York, NY, USA, pp. 26:1–26:27, 2016, February. [bibtex] [pdf] [doi]
2015
[J3], , "Safe and Stabilizing Distributed Multi-Path Cellular Flows", In Theoretical Computer Science, Elsevier, vol. , no. , , pp. 1–46, 2015, February. [abstract] [software / source code] [bibtex] [pdf] [doi]
2014
[J2], , , "Virtual Prototyping for Distributed Control of a Fault-Tolerant Modular Multilevel Inverter for Photovoltaics", In IEEE Transactions on Energy Conversion, vol. 29, , pp. 841–850, 2014, December. (arxiv preprint) [abstract] [bibtex] [pdf] [doi] [cites]
2011
[J1], , "Safe Flocking in Spite of Actuator Faults using Directional Failure Detectors", In Journal of Nonlinear Systems and Applications, Watam Press Inc., vol. 2, no. 1-2, Waterloo, Ontario, Canada, pp. 73–95, 2011, April. (pdf (publisher), doi) [abstract] [bibtex] [pdf] [cites]

Conference Papers (30)

2017
[C30], , , , , "Hyperproperties of real-valued signals", In 15th ACM-IEEE International Conference on Formal Methods and Models for System Design (MEMOCODE 2017), IEEE, 2017, October. [bibtex] [pdf]
[C29], , , "Operational models of piecewise-smooth systems", In 17th ACM SIGBED International Conference on Embedded Software (EMSOFT 2017), 2017, October. [bibtex] [pdf] [doi]
[C28], , "On Reachable Set Estimation for Discrete-Time Switched Linear Systems under Arbitrary Switching", In 30th IEEE American Control Conference (ACC 2017), 2017, july. [bibtex] [pdf] [doi]
[C27], , , "Verifying safety and persistence properties of hybrid systems using flowpipes and continuous invariants", In 9th NASA Formal Methods Symposium (NFM 2017), 2017, May. [bibtex] [pdf] [doi]
[C26], , , , , , "Abnormal Data Classification Using Time-Frequency Temporal Logic", In 20th Intl. Conf. on Hybrid Systems: Computation and Control (HSCC 2017), ACM, 2017, April. [bibtex] [pdf] [doi]
2016
[C25], , , "Decoupled simulating abstractions of non-linear ordinary differential equations", Chapter in Proceedings of the 21st International Symposium on Formal Methods (FM 2016), Limassol, Cyprus, 2016, December. [abstract] [bibtex] [pdf] [doi]
[C24], , , "Reachable Set Estimation and Control for Switched Linear Systems with Dwell-Time Restriction", In Proceedings of the 55th IEEE Conference on Decision and Control (CDC 2016), Las Vegas, NV, USA, 2016, December. [bibtex] [pdf] [doi]
[C23], , , , , , , , , , , , , , "Tutorial: Software Tools for Hybrid Systems Verification, Transformation, and Synthesis: C2E2, HyST, and TuLiP", In Proceedings of the IEEE Multi-Conference on Systems and Control (MSC 2016), Las Vegas, NV, USA, 2016, September. [bibtex] [pdf] [doi]
[C22], , , , , "Probabilistic Formal Verification of the SATS Concept of Operation", In Proceedings of the 8th NASA Formal Methods (NFM 2016) International Symposium (Sanjai Rayadurgam, Oksana Tkachuk, eds.), Springer International Publishing, pp. 191–205, 2016, june. [bibtex] [pdf] [doi]
[C21], , , , , "Scalable Static Hybridization Methods for Analysis of Nonlinear Systems", In 19th Intl. Conf. on Hybrid Systems: Computation and Control (HSCC 2016), ACM, 2016, April. [bibtex] [pdf] [doi]
2015
[C20], , "Periodically-Scheduled Controller Analysis using Hybrid Systems Reachability and Continuization", In 36th IEEE Real-Time Systems Symposium (RTSS 2015), IEEE Computer Society, San Antonio, Texas, 2015, December. [bibtex] [pdf]
[C19], , , , "Runtime Verification of Model-based Development Environments", In 15th International Conference on Runtime Verification (RV 2015), Vienna, Austria, 2015, September. [bibtex] [pdf]
[C18], , , "A Survey of Electrical and Electronic (E/E) Notifications for Motor Vehicles", In 24th NHTSA International Technical Conference on the Enhanced Safety of Vehicles (ESV), Gothenburg, Sweden, pp. 1–15, 2015, June. (publisher PDF) [abstract] [bibtex] [pdf] [doi] [cites]
[C17], , , "Cyber-Physical Specification Mismatch Identification with Dynamic Analysis", In 6th International Conference on Cyber-Physical Systems (ICCPS 2015), ACM/IEEE, Seattle, Washington, 2015, April. (Hynger software tool) [software / source code] [bibtex] [pdf]
[C16], , , "HyST: A Source Transformation and Translation Tool for Hybrid Automaton Models", In 18th International Conference on Hybrid Systems: Computation and Control (HSCC 2015), ACM, Seattle, Washington, 2015, April. (Hyst software tool) [software / source code] [bibtex] [pdf]
[C15], , , , "Verified Planar Formation Control Algorithms by Composition of Primitives", In AIAA SciTech, AIAA, Kissimmee, Florida, 2015, January. [bibtex] [pdf]
2014
[C14], , , , "Real-Time Reachability for Verified Simplex Design", In 35th IEEE Real-Time Systems Symposium (RTSS 2014), IEEE Computer Society, Rome, Italy, 2014, December. [slides] [bibtex] [pdf]
[C13], , "Anonymized Reachability of Hybrid Automata Networks", In Proceedings of the 12th International Conference on Formal Modeling and Analysis of Timed Systems (FORMATS 2014), Florence, Italy, pp. , 2014, September. [abstract] [bibtex] [pdf] [doi] [cites]
2013
[C12], , "Invariant Synthesis for Verification of Parameterized Cyber-Physical Systems with Applications to Aerospace Systems", In Proceedings of the AIAA Infotech at Aerospace Conference (AIAA Infotech 2013) (, ed.), AIAA, vol. , Boston, MA, pp. , 2013, August. [abstract] [bibtex] [pdf] [doi] [cites]
[C11], , , , , , , , "Abstraction-Based Guided Search for Hybrid Systems", In Proceedings of the 20th International SPIN Symposium on Model Checking of Software (SPIN 2013), Stony Brook, New York, USA, pp. , 2013, July. [abstract] [bibtex] [pdf] [doi] [cites]
[C10], , , "Reachability Analysis of Closed-Loop Switching Power Converters", In Proceedings of the 4th IEEE Power and Energy Conference at Illinois (PECI 2013), Urbana, Illinois, USA, pp. , 2013, February. [abstract] [bibtex] [pdf] [doi] [cites]
2012
[C9], , , , "Static and Dynamic Analysis of Timed Distributed Traces", In Proceedings of the 33rd IEEE Real-Time Systems Symposium (RTSS 2012), San Juan, Puerto Rico, pp. 173–182, 2012, December. [abstract] [bibtex] [pdf] [doi] [cites]
[C8], , , , , "Satellite Rendezvous and Conjunction Avoidance: Case Studies in Verification of Nonlinear Hybrid Systems", Chapter in Proceedings of the 18th International Conference on Formal Methods (FM 2012) (Dimitra Giannakopoulou, Dominique Méry, eds.), Springer Berlin Heidelberg, vol. 7436, Paris, France, pp. 252–266, 2012, August. [abstract] [bibtex] [pdf] [doi] [cites]
[C7], , "A Small Model Theorem for Rectangular Hybrid Automata Networks", In Proceedings of the IFIP International Conference on Formal Techniques for Distributed Systems, Joint 14th Formal Methods for Open Object-Based Distributed Systems and 32nd Formal Techniques for Networked and Distributed Systems (FORTE/FMOODS 2012), Stockholm, Sweden, pp. , 2012, June. (Best Paper Award for DisCoTec, Passel tool and specification source, Passel tool overview) [abstract] [software / source code] [bibtex] [pdf] [doi] [cites]
[C6], , "Parameterized Verification of Distributed Cyber-Physical Systems: An Aircraft Landing Protocol Case Study", In Proceedings of the 3rd ACM/IEEE International Conference on Cyber-Physical Systems (ICCPS 2012), Beijing, China, pp. 161–170, 2012, April. (source code) [abstract] [bibtex] [pdf] [doi] [cites]
[C5], , , "Design Verification Methods for Switching Power Converters", In Proceedings of the 3rd IEEE Power and Energy Conference at Illinois (PECI 2012), Urbana, Illinois, USA, pp. 1–6, 2012, February. [abstract] [bibtex] [pdf] [doi] [cites]
2011
[C4], , , "Stability of Digitally Interconnected Linear Systems", In Proceedings of the 50th IEEE Conference on Decision and Control and European Control Conference (CDC ECC 2011), Orlando, Florida, USA, pp. 2687–2692, 2011, December. [abstract] [bibtex] [pdf] [doi] [cites]
[C3], , "Turbo-Alternator Stalling Protection using Available Power Estimate", In Proceedings of the 2nd Annual IEEE Power and Energy Conference at Illinois (PECI 2011), Urbana, Illinois, USA, 2011, February. (Best Paper Award) [abstract] [bibtex] [pdf] [doi] [cites]
2010
[C2], , "Safe Flocking in Spite of Actuator Faults", Chapter in 12th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS 2010) (Shlomi Dolev, Jorge Cobb, Michael Fischer, Moti Yung, eds.), Springer Berlin / Heidelberg, vol. 6366, pp. 588–602, 2010, September. [abstract] [bibtex] [pdf] [doi] [cites]
[C1], , , "Safe and Stabilizing Distributed Cellular Flows", In 30th IEEE International Conference on Distributed Computing Systems (ICDCS 2010), Genoa, Italy, pp. 577–578, 2010, June. [abstract] [bibtex] [pdf] [doi] [cites]

Workshop Papers (14)

2017
[W14], , , , "Computer-Aided Formal Verification of Power Electronics Circuits", In 8th International Workshop on Frontiers in Analog CAD (FAC), Frankfurt, Germany, 2017, july. [bibtex] [pdf]
[W13], , , "Reachability Analysis of Transformer-Isolated DC-DC Converters (Benchmark Proposal)", In 4th Applied Verification for Continuous and Hybrid Systems Workshop (ARCH), Pittsburgh, PA, 2017, April. [bibtex] [pdf]
[W12], "ARCH-COMP17 Repeatability Evaluation Report", In 4th Applied Verification for Continuous and Hybrid Systems Workshop (ARCH), Pittsburgh, PA, 2017, April. [bibtex] [pdf]
[W11], , , , "Distributed Autonomous Systems (Benchmark Proposal)", In 4th Applied Verification for Continuous and Hybrid Systems Workshop (ARCH), Pittsburgh, PA, 2017, April. [bibtex] [pdf]
2016
[W10], , , "CyFuzz: : A Differential Testing Framework for Cyber-Physical Systems Development Environments", In 6th International Workshop Workshop on Design, Modeling and Evaluation of Cyber Physical Systems (CyPhy 2016), Pittsburgh, PA, 2016, August. [bibtex] [pdf] [doi]
[W9], , , "Charge Pump Phase-Locked Loops and Full Wave Rectifiers for Reachability Analysis (Benchmark Proposal)", In 3rd Applied Verification for Continuous and Hybrid Systems Workshop (ARCH), Vienna, Austria, 2016, April. [bibtex] [pdf]
[W8], , , "Non-linear Continuous Systems for Safety Verification (Benchmark Proposal)", In 3rd Applied Verification for Continuous and Hybrid Systems Workshop (ARCH), Vienna, Austria, 2016, April. [bibtex] [pdf]
[W7], , , "Large-Scale Linear Systems from Order-Reduction (Benchmark Proposal)", In 3rd Applied Verification for Continuous and Hybrid Systems Workshop (ARCH), Vienna, Austria, 2016, April. [bibtex] [pdf]
2015
[W6], , , , "Quantified Bounded Model Checking for Rectangular Hybrid Automata", In 9th International Workshop on Constraints in Formal Verification (CFV 2015), Austin, Texas, 2015, November. [bibtex] [pdf]
[W5], , , "HyST: A Source Transformation and Translation Tool for Hybrid Automaton Models", In 1st International Workshop on Symbolic and Numerical Methods for Reachability Analysis (SNR 2015), Co-Located with the 27th International Conference on Computer Aided Verification (CAV 2015), San Francisco, California, 2015, July. [bibtex] [pdf]
[W4], , , "Benchmark: A Nonlinear Reachability Analysis Test Set from Numerical Analysis", In 2nd Applied Verification for Continuous and Hybrid Systems Workshop (ARCH 2015), Seattle, Washington, pp. , 2015, April. (model source code) [abstract] [bibtex] [pdf] [doi] [cites]
[W3], , , , "Benchmark Generator for Stratified Controllers of Tank Networks", In 2nd Applied Verification for Continuous and Hybrid Systems Workshop (ARCH 2015), Seattle, Washington, pp. , 2015, April. (model source code) [abstract] [bibtex] [pdf] [doi] [cites]
2014
[W2], , "Benchmark: DC-to-DC Switched-Mode Power Converters (Buck Converters, Boost Converters, and Buck-Boost Converters)", In Applied Verification for Continuous and Hybrid Systems Workshop (ARCH 2014), Berlin, Germany, pp. , 2014, April. [abstract] [software / source code] [bibtex] [pdf] [doi] [cites]
[W1], , , , , , , "Model-Based Design and Analysis of a Reconfigurable Continuous-Culture Bioreactor (Work-in-Progress)", In Fourth ACM Workshop on Design, Modeling, and Evaluation of Cyber Physical Systems (CyPhy 2014), Berlin, Germany, pp. , 2014, April. (ACM Authorizer) [abstract] [bibtex] [pdf] [doi] [cites]

Theses (2)

2013
[TH2], "Uniform Verification of Safety for Parameterized Networks of Hybrid Automata", PhD thesis, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, 2013, August. (doi) [abstract] [software / source code] [bibtex] [pdf] [cites]
2010
[TH1], "Fault-Tolerant Distributed Cyber-Physical Systems: Two Case Studies", Master's thesis, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, 2010, May. (doi) [abstract] [bibtex] [pdf] [cites]

Technical Reports (1)

2010
[R1], , "Safe and Stabilizing Distributed Flocking In Spite of Actuator Faults", UILU-ENG-10-2204 (CRHC-10-02), University of Illinois at Urbana-Champaign, no. UILU-ENG-10-2204 (CRHC-10-02), Urbana, IL 61801, USA, 2010, May. [bibtex] [pdf]

Patents (1)

2015
[P1], , , , , , "Control of a component of a downhole tool", no. US 9222352, 2015, December. (DOI) [abstract] [bibtex] [pdf]

Demos/Posters/Abstracts (3)

2015
[D3], , , , "HyRG: a random generation tool for affine hybrid automata", Presented at 18th International Conference on Hybrid Systems: Computation and Control (HSCC 2015) Poster/Demo Session, 2015, April. (HyRG Software Tool) [software / source code] [bibtex] [pdf] [doi] [cites]
2009
[D2], , "Handling Failures in Cyber-Physical Systems: Potential Directions", Presented at RTSS 2009 PhD Student Forum, 2009, December. (Award for Most Interesting Cyber-Physical Systems Research Problem) [abstract] [slides] [bibtex] [pdf] [cites]
[D1], , "Power Usage of Time and Event-Triggered Paradigms: A Case Study", Presented at RTAS 2009 Poster Session, 2009, April. [abstract] [slides] [software / source code] [bibtex] [pdf] [cites]

The entire BiBteX file is available here.

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