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Reminiscences of a Real-Time Researcher

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Real Time and Such

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 15230))

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Abstract

I give a personal account about the wave of new research activities that rose in the 1990s on the specification, verification, and control of real-time systems.

For Wang, an early conspirator

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Notes

  1. 1.

    The second references are examples illustrating that the original contributions have lasting impact.

  2. 2.

    Clarke and others used the term SMC synonymous with BDD-based model checking.

  3. 3.

    We joined forces for the journal paper [4].

  4. 4.

    A semi-algorithm may not terminate; in verification it ensures soundness, but not completeness.

References

  1. Abadi, M., Lamport, L.: An old-fashioned recipe for real time. In: Real-Time: Theory in Practice, REX Workshop, volume 600 of Lecture Notes in Computer Science, pages 1–27. Springer (1991)

    Google Scholar 

  2. Ábrahám, E., Mazo Jr, M. editors: Proc. 27th Conference on Hybrid Systems: Computation and Control, HSCC. ACM (2024)

    Google Scholar 

  3. Alur, R., Courcoubetis, C., Dill, D.L.: Model checking for real-time systems. In: Proc. 5th Symposium on Logic in Computer Science, LICS, pages 414–425. IEEE Computer Society (1990)

    Google Scholar 

  4. Alur, R., Courcoubetis, C., Halbwachs, N., Henzinger, T.A., Ho, P., Nicollin, X., Olivero, A., Sifakis, J., Yovine, S.: The algorithmic analysis of hybrid systems. Theor. Comput. Sci. 138(1), 3–34 (1995)

    Article  MathSciNet  Google Scholar 

  5. Alur, R., Courcoubetis, C., Henzinger, T.A., Ho, P.: Hybrid automata: An algorithmic approach to the specification and verification of hybrid systems. In: Hybrid Systems, volume 736 of Lecture Notes in Computer Science, pages 209–229. Springer, (1992)

    Google Scholar 

  6. Alur, R., Dill, D.L.: Automata for modeling real-time systems. In Automata, Languages and Programming, 17th International Colloquium, ICALP, volume 443 of Lecture Notes in Computer Science, pages 322–335. Springer, 1990

    Google Scholar 

  7. Alur, R., Dill, D.L.: A theory of timed automata. Theor. Comput. Sci. 126(2), 183–235 (1994)

    Article  MathSciNet  Google Scholar 

  8. Alur, R., Feder, T., Henzinger, T.A.: The benefits of relaxing punctuality. In: Proc. 10th Symposium on Principles of Distributed Computing, PODC, pages 139–152. ACM (1991)

    Google Scholar 

  9. Alur, R., Fix, L., Henzinger, T.A.: A determinizable class of timed automata. In: Computer Aided Verification, 6th Conference, CAV, volume 818 of Lecture Notes in Computer Science, pages 1–13. Springer (1994)

    Google Scholar 

  10. Alur, R., Henzinger, T.A.: A really temporal logic. In: Proc. 30th Symposium on Foundations of Computer Science, FOCS, pages 164–169. IEEE Computer Society (1989)

    Google Scholar 

  11. Alur, R., Henzinger, T.A.: Real-time logics: Complexity and expressiveness. In: Proc. 5th Symposium on Logic in Computer Science, LICS, pages 390–401. IEEE Computer Society (1990)

    Google Scholar 

  12. Alur, R., Henzinger, T.A.: Back to the future: Towards a theory of timed regular languages. In: Proc. 33rd Symposium on Foundations of Computer Science, FOCS, pages 177–186. IEEE Computer Society (1992)

    Google Scholar 

  13. Alur, R., Henzinger, T.A.: Reactive modules. In: Proc. 11th Symposium on Logic in Computer Science, LICS, pages 207–218. IEEE Computer Society (1996)

    Google Scholar 

  14. Alur, R., Henzinger, T.A.: Modularity for timed and hybrid systems. In: Concurrency Theory, 8th Conference, CONCUR, volume 1243 of Lecture Notes in Computer Science, pages 74–88. Springer (1997)

    Google Scholar 

  15. Alur, R., Henzinger, T.A.: Real-time system = discrete system + clock variables. Int. J. Softw. Tools Technol. Transf. 1(1–2), 86–109 (1997)

    Article  Google Scholar 

  16. Alur, R., Henzinger, T.A., Ho, P.: Automatic symbolic verification of embedded systems. In Proc. 14th Real-Time Systems Symposium, RTSS, pages 2–11. IEEE Computer Society, (1993)

    Google Scholar 

  17. Alur, R., Henzinger, T.A., Kupferman, O.: Alternating-time temporal logic. In: Proc. 38th Symposium on Foundations of Computer Science, FOCS, pages 100–109. IEEE Computer Society (1997)

    Google Scholar 

  18. Alur, R., Henzinger, T.A., Sontag, E.D. editors: Hybrid Systems III: Verification and Control, volume 1066 of Lecture Notes in Computer Science. Springer (1996)

    Google Scholar 

  19. Antsaklis, P.J., Kohn, W., Nerode, A., Sastry, S. editors: Hybrid Systems II, volume 999 of Lecture Notes in Computer Science. Springer (1995)

    Google Scholar 

  20. Antsaklis, P.J., Kohn, W., Nerode, A., Sastry, S. editors: Hybrid Systems IV, volume 1273 of Lecture Notes in Computer Science. Springer (1997)

    Google Scholar 

  21. Asarin, E., Maler, O., Pnueli, A.: Symbolic controller synthesis for discrete and timed systems. In: Hybrid Systems II, volume 999 of Lecture Notes in Computer Science, pages 1–20. Springer (1994)

    Google Scholar 

  22. Bengtsson, J., Larsen, K.G., Larsson, F., Pettersson, P., Yi, W.: Uppaal: A tool suite for automatic verification of real-time systems. In: Hybrid Systems III: Verification and Control, volume 1066 of Lecture Notes in Computer Science, pages 232–243. Springer (1995)

    Google Scholar 

  23. Bose, S., Henzinger, T.A., Lehtinen, K., Schewe, S., Totzke, P.: History-deterministic timed automata are not determinizable. In: Reachability Problems, 16th Conference, RP, volume 13608 of Lecture Notes in Computer Science, pages 67–76. Springer (2022)

    Google Scholar 

  24. Bouyer, P., Markey, N., Ouaknine, J., Worrell, J.: The cost of punctuality. In: Proc. 22nd Symposium on Logic in Computer Science, LICS, pages 109–120. IEEE Computer Society (2007)

    Google Scholar 

  25. Burch, J.R., Clarke, E.M., McMillan, K.L., Dill, D.L., Hwang, L.J.: Symbolic model checking: \(10^{20}\) states and beyond. In: Proc. 5th Symposium on Logic in Computer Science, LICS, pages 428–439. IEEE Computer Society (1990)

    Google Scholar 

  26. Büchi, J.R., Landweber, L.H.: Solving sequential conditions by finite-state strategies. Trans. AMS 38(27), 295–311 (1969)

    Article  MathSciNet  Google Scholar 

  27. Chaochen, Z., Hoare, C.A.R., Ravn, A.P.: A calculus of durations. Inf. Process. Lett. 40(5), 269–276 (1991)

    Article  MathSciNet  Google Scholar 

  28. Chatterjee, K., Henzinger, T.A.: Value iteration. In: 25 Years of Model Checking: History, Achievements, Perspectives, volume 5000 of Lecture Notes in Computer Science, pages 107–138. Springer (2008)

    Google Scholar 

  29. Clarke, E.M., Emerson, E.A.: Design and synthesis of synchronization skeletons using branching-time temporal logic. In: Logics of Programs, Workshop, volume 131 of Lecture Notes in Computer Science, pages 52–71. Springer, (1981)

    Google Scholar 

  30. Daws, C., Olivero, A., Yovine, S.: Verifying ET-Lotos programs with Kronos. In: Formal Description Techniques, 7th WG6.1 Conference, FORTE, volume 6 of IFIP Proceedings, pages 227–242. Chapman & Hall (1994)

    Google Scholar 

  31. de Alfaro, L., Faella, M., Henzinger, T.A., Majumdar, R., Stoelinga, M.: The element of surprise in timed games. In: Concurrency Theory, 14th Conference, CONCUR, volume 2761 of Lecture Notes in Computer Science, pages 142–156. Springer (2003)

    Google Scholar 

  32. de Alfaro, L., Henzinger, T.A., Kupferman, O.: Concurrent reachability games. In: Proc. 39th Symposium on Foundations of Computer Science, FOCS, pages 564–575. IEEE Computer Society (1998)

    Google Scholar 

  33. de Alfaro, L., Henzinger, T.A., Majumdar, R.: From verification to control: Dynamic programs for omega-regular objectives. In: Proc. 16th Symposium on Logic in Computer Science, LICS, pages 279–290. IEEE Computer Society (2001)

    Google Scholar 

  34. de Alfaro, L., Henzinger, T.A., Majumdar, R.: Symbolic algorithms for infinite-state games. In: Concurrency Theory, 12th Conference, CONCUR, volume 2154 of Lecture Notes in Computer Science, pages 536–550. Springer (2001)

    Google Scholar 

  35. de Alfaro, L., Majumdar, R.. Quantitative solution of omega-regular games. In: Proc. on 33rd Symposium on Theory of Computing, STOC, pages 675–683. ACM (2001)

    Google Scholar 

  36. de Bakker, J.W., Huizing, C., de Roever, W.P., Rozenberg, G. editors: Real-Time: Theory in Practice, REX Workshop, volume 600 of Lecture Notes in Computer Science. Springer (1992)

    Google Scholar 

  37. Dill, D.L.: Timing assumptions and verification of finite-state concurrent systems. In: Automatic Verification Methods for Finite-State Systems, Workshop, volume 407 of Lecture Notes in Computer Science, pages 197–212. Springer (1989)

    Google Scholar 

  38. Grossman, R.L., Nerode, A., Ravn, A.P., Rischel, H. editors: Hybrid Systems, volume 736 of Lecture Notes in Computer Science. Springer (1993)

    Google Scholar 

  39. Gupta, V., Henzinger, T.A., Jagadeesan, R.: Robust timed automata. In: Hybrid and Real-Time Systems, Workshop, HART, volume 1201 of Lecture Notes in Computer Science, pages 331–345. Springer (1997)

    Google Scholar 

  40. Hasrat, I.R., Jensen, P.G., Larsen, K.G., Srba, J.: A toolchain for domestic heat-pump control using Uppaal Stratego. Sci. Comput. Program. 230, 102987 (2023)

    Article  Google Scholar 

  41. Henzinger, T.A.: Half-order modal logic: How to prove real-time properties. In: Proc. 9th Symposium on Principles of Distributed Computing, PODC, pages 281–296. ACM (1990)

    Google Scholar 

  42. Henzinger, T.A.: Sooner is safer than later. Inf. Process. Lett. 43(3), 135–141 (1992)

    Article  MathSciNet  Google Scholar 

  43. Henzinger, T.A.: The theory of hybrid automata. In: Proc. 11th Symposium on Logic in Computer Science, LICS, pages 278–292. IEEE Computer Society (1996)

    Google Scholar 

  44. Henzinger, T.A., Ho, P.: HyTech: The Cornell HYbrid TECHnology tool. In: Hybrid Systems II, volume 999 of Lecture Notes in Computer Science, pages 265–293. Springer (1994)

    Google Scholar 

  45. Henzinger, T.A., Ho, P., Wong-Toi, H.: HyTech: A model checker for hybrid systems. Int. J. Softw. Tools Technol. Transf. 1(1–2), 110–122 (1997)

    Article  Google Scholar 

  46. Henzinger, T.A., Ho, P., Wong-Toi, H.: Algorithmic analysis of nonlinear hybrid systems. IEEE Trans. Autom. Control 43(4), 540–554 (1998)

    Article  MathSciNet  Google Scholar 

  47. Henzinger, T.A., Horowitz, B., Majumdar, R.: Rectangular hybrid games. In: Concurrency Theory, 10th Conference, CONCUR, volume 1664 of Lecture Notes in Computer Science, pages 320–335. Springer (1999)

    Google Scholar 

  48. Henzinger, T.A., Kopke, P.W.: State equivalences for rectangular hybrid automata. In: Concurrency Theory, 7th Conference, CONCUR, volume 1119 of Lecture Notes in Computer Science, pages 530–545. Springer (1996)

    Google Scholar 

  49. Henzinger, T.A., Kopke, P.W.: Discrete-time control for rectangular hybrid automata. In: Automata, Languages and Programming, 24th International Colloquium, ICALP, volume 1256 of Lecture Notes in Computer Science, pages 582–593. Springer (1997)

    Google Scholar 

  50. Henzinger, T.A., Kopke, P.W., Puri, A., Varaiya, P.: What’s decidable about hybrid automata? In: Proc. 27th Symposium on Theory of Computing, STOC, pages 373–382. ACM (1995)

    Google Scholar 

  51. Henzinger, T.A., Majumdar, R., Raskin, J.: A classification of symbolic transition systems. ACM Trans. Comput. Log. 6(1), 1–32 (2005)

    Article  MathSciNet  Google Scholar 

  52. Henzinger, T.A., Manna, Z., Pnueli, A.: An interleaving model for real-time. In: Proc. 5th Jerusalem Conference on Information Technology, pages 717–730. IEEE Computer Society (1990)

    Google Scholar 

  53. Henzinger, T.A., Manna, Z., Pnueli, A.: Temporal proof methodologies for real-time systems. In: Proc. 18th Symposium on Principles of Programming Languages, POPL, pages 353–366. ACM (1991)

    Google Scholar 

  54. Henzinger, T.A., Manna, Z., Pnueli, A.: What good are digital clocks? In: Automata, Languages and Programming, 19th International Colloquium, ICALP, volume 623 of Lecture Notes in Computer Science, pages 545–558. Springer (1992)

    Google Scholar 

  55. Henzinger, T.A., Nicollin, X., Sifakis, J., Yovine, S.: Symbolic model checking for real-time systems. In: Proc. 7th Symposium on Logic in Computer Science, LICS, pages 394–406. IEEE Computer Society, (1992)

    Google Scholar 

  56. Henzinger, T.A., Otop, J.: Model measuring for discrete and hybrid systems. Nonlinear Anal. 23, 166–190 (2017)

    MathSciNet  Google Scholar 

  57. Henzinger, T.A., Raskin, J.:. Robust undecidability of timed and hybrid systems. In: Hybrid Systems: Computation and Control, 3rd Workshop, HSCC, volume 1790 of Lecture Notes in Computer Science, pages 145–159. Springer (2000)

    Google Scholar 

  58. Henzinger, T.A., Raskin, J., Schobbens, P.: The regular real-time languages. In: Automata, Languages and Programming, 25th International Colloquium, ICALP, volume 1443 of Lecture Notes in Computer Science, pages 580–591. Springer (1998)

    Google Scholar 

  59. Henzinger, T.A., Sastry, S. editors: Hybrid Systems: Computation and Control, 1st Workshop, HSCC, volume 1386 of Lecture Notes in Computer Science. Springer, (1998)

    Google Scholar 

  60. Hoffmann, G., Wong-Toi, H.: The input-output control of real-time discrete-event systems. In: Proc. 13th Real-Time Systems Symposium, RTSS, pages 256–265. IEEE Computer Society (1992)

    Google Scholar 

  61. Jahanian, F., Mok, A.K.: Safety analysis of timing properties in real-time systems. IEEE Trans. Software Eng. 12(9), 890–904 (1986)

    Article  Google Scholar 

  62. Koymans, R.: Specifying real-time properties with metric temporal logic. Real Time Syst. 2(4), 255–299 (1990)

    Article  Google Scholar 

  63. Lamport, L.: Specifying Systems: The TLA+ Language and Tools for Hardware and Software Engineers. Addison-Wesley (2002)

    Google Scholar 

  64. Larsen, K.-G. , Pettersson, P., Yi, W.: Compositional and symbolic model-checking of real-time systems. In: Proc. 16th Real-Time Systems Symposium, RTSS, pages 76–87. IEEE Computer Society (1995)

    Google Scholar 

  65. Larsen, K.G., Pettersson, P., Yi, W.: Uppaal in a nutshell. Int. J. Softw. Tools Technol. Transf. 1(1–2), 134–152 (1997)

    Article  Google Scholar 

  66. Lichtenstein, O., Pnueli, A.: Checking that finite-state concurrent programs satisfy their linear specification. In: Proc. 12th Symposium on Principles of Programming Languages, POPL, pages 97–107. ACM (1985)

    Google Scholar 

  67. Maler, O., Manna, Z., Pnueli, A.: From timed to hybrid systems. In: Real-Time: Theory in Practice, REX Workshop, volume 600 of Lecture Notes in Computer Science, pages 447–484. Springer (1991)

    Google Scholar 

  68. Manna, Z., Pnueli, A.: The Temporal Logic of Reactive and Concurrent Systems: Specification. Springer (1992)

    Google Scholar 

  69. Manna, Z., Pnueli, A.: Temporal Verification of Reactive Systems: Safety. Springer (1995)

    Google Scholar 

  70. Nerode, A., Kohn, W.: Models for hybrid systems: Automata, topologies, controllability, observability. In: Hybrid Systems, volume 736 of Lecture Notes in Computer Science, pages 317–356. Springer (1992)

    Google Scholar 

  71. Nicollin, X., Olivero, A., Sifakis, J., Yovine, S.: An approach to the description and analysis of hybrid systems. In: Hybrid Systems, volume 736 of Lecture Notes in Computer Science, pages 149–178. Springer (1992)

    Google Scholar 

  72. Nicollin, X., Richier, J., Sifakis, J., Voiron, J.: ATP: An algebra for timed processes. In Programming concepts and methods, IFIP WG2.2 & WG2.3 Working Conference on Programming Concepts and Methods, pages 415–442. North-Holland (1990)

    Google Scholar 

  73. Nicollin, X., Sifakis, J.: An overview and synthesis on timed process algebras. In: Computer Aided Verification, 3rd Workshop, CAV, volume 575 of Lecture Notes in Computer Science, pages 376–398. Springer (1991)

    Google Scholar 

  74. Ouaknine, J., Worrell, J.: On the decidability and complexity of metric temporal logic over finite words. Log. Methods Comput. Sci., 3(1) (2007)

    Google Scholar 

  75. Pnueli, A.: The temporal logic of programs. In: Proc. 18th Symposium on Foundations of Computer Science, FOCS, pages 46–57. IEEE Computer Society (1977)

    Google Scholar 

  76. Pnueli, A., Rosner, R.: On the synthesis of a reactive module. In: Proc. 16th Symposium on Principles of Programming Languages, POPL, pages 179–190. ACM (1989)

    Google Scholar 

  77. Queille, J., Sifakis, J.: Specification and verification of concurrent systems in Cesar. In: Symposium on Programming, Fifth Colloquium, volume 137 of Lecture Notes in Computer Science, pages 337–351. Springer (1982)

    Google Scholar 

  78. Ramadge, P.J., Wonham, W.M.: The control of discrete-event systems. Proc. IEEE 77(1), 81–98 (1989)

    Article  Google Scholar 

  79. P. Tabuada. Verification and Control of Hybrid Systems: A Symbolic Approach. Springer (2009)

    Google Scholar 

  80. Yi, W., Pettersson, P., Daniels, M.: Automatic verification of real-time communicating systems by constraint-solving. In: Formal Description Techniques, 7th WG6.1 Conference, FORTE, volume 6 of IFIP Proceedings, pages 243–258. Chapman & Hall (1994)

    Google Scholar 

  81. Yovine, S.: Kronos: A verification tool for real-time systems. Int. J. Softw. Tools Technol. Transf. 1(1–2), 123–133 (1997)

    Article  Google Scholar 

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Acknowledgements and apologies

I thank all my collaborators over the years. None of the mentioned contributions would have been possible without them. I also apologize for all omissions. The selection of contributions in this essay reflects primarily my personal involvement rather than any measure of importance.

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Correspondence to Thomas A. Henzinger .

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Henzinger, T.A. (2025). Reminiscences of a Real-Time Researcher. In: Graf, S., Pettersson, P., Steffen, B. (eds) Real Time and Such. Lecture Notes in Computer Science, vol 15230. Springer, Cham. https://doi.org/10.1007/978-3-031-73751-0_12

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