Correct System Design

Recent Publications

 

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1 Recent Publications (BibTeX Source)




@INPROCEEDINGS{avacs-h3-dec-11,
  AUTHOR = {M. Hilscher AND S. Linker AND E.-R. Olderog AND A.P.
		  Ravn},
  TITLE = {An Abstract Model for Proving Safety of Multi-Lane Traffic
		  Manoeuvres},
  BOOKTITLE = {Int'l Conf.\ on Formal Engineering Methods (ICFEM)},
  YEAR = {2011},
  EDITOR = {Shengchao Qin AND Zongyan Qiu},
  VOLUME = {6991},
  SERIES = {Lecture Notes in Computer Science},
  MONTH = {Oct.},
  PUBLISHER = {Springer-Verlag},
  NOTE = {The original publication is available at \url{http://www.springerlink.com}{www.springerlink.com}. (to appear)},
  SUBPROJECT = {H3},
  ABSTRACT = { We present an approach to prove safety (collision
		  freedom) of multi-lane motorway trac with lane-change
		  manoeuvres. This is ultimately a hybrid veri cation problem
		  due to the continuous dynamics of the cars. We abstract
		  from the dynamics by introducing a new spatial interval
		  logic based on the view of each car. To guarantee safety,
		  we present two variants of a lane-change controller, one
		  with perfect knowledge of the safety envelopes of
		  neighbouring cars and one which takes only the size of the
		  neighbouring cars into account. Based on these controllers
		  we provide a local safety proof for unboundedly many cars
		  by showing that at any moment the reserved space of each
		  car is disjoint from the reserved space of any other car.
		  }
}


@INPROCEEDINGS{AVACS-H3-BRG-11,
  AUTHOR = {J.-D. Quesel AND M. Fr\"{a}nzle AND W. Damm},
  TITLE = {Crossing the bridge between similar games},
  BOOKTITLE = {Formal Modeling and Analysis of Timed Systems - 9th International
	Conference (FORMATS), Aalborg, Denmark, 21-23 September, 2011. Proceedings},
  YEAR = {2011},
  EDITOR = {Stavros Tripakis and Uli Fahrenberg},
  SERIES = {LNCS},
  VOLUME = {6919},
  PAGES = {160--176},
  MONTH = {Sep.},
  PUBLISHER = {Springer},
  NOTE = {The original publication is available at \url{http://www.springerlink.com/content/e6r94n5820k08626}{www.springerlink.com}.},
  SUBPROJECT = {H3},
  PDF = {http://csd.informatik.uni-oldenburg.de/~jdq/paper/bridging.pdf},
  SLIDES = {http://csd.informatik.uni-oldenburg.de/~jdq/slides/bridging-formats-2011-09-21.pdf},
  ABSTRACT = {
	  Specifications and implementations of complex physical systems tend to
	  differ as low level effects such as sampling are often ignored when
	  high level models are created. Thus, the low level models are often
	  not exact refinements of the high level specification. However, they
	  are similar to those. To bridge the gap between those models, we
	  study robust simulation relations for hybrid systems. We identify a
	  family of robust simulation relations that allow for certain bounded
	  deviations in the behavior of a system specification and its
	  implementation in both values of the system variables and timings. We
	  show that for this relaxed version of simulation a broad class of
	  logical properties is preserved. The question whether two systems are
	  in simulation relation can be reduced to a reach avoid problem for
	  hybrid games. We provide a sufficient condition under which a winning
	  strategy for these games exists.}
}


@ARTICLE{FLO+2011,
  AUTHOR = {Johannes Faber and Sven Linker and Ernst-R{\"u}diger Olderog and
Jan-David Quesel},
  TITLE = {Syspect - Modelling, Specifying, and Verifying Real-Time Systems with
Rich Data},
  JOURNAL = {International Journal of Software and Informatics},
  YEAR = {2011},
  VOLUME = {5},
  NUMBER = {1-2},
  PART = {1},
  PAGES = {117--137},
  NOTE = {ISSN 1673-7288.},
  URL = {http://www.ijsi.org/IJSI/ch/reader/create_pdf.aspx?file_no=i78&flag=1&journal_id=ijsi},
  ABSTRACT = {We introduce the graphical tool Syspect for modelling, specifying,
                  and automatically verifying reactive systems with continuous
                  real-time constraints and complex, possibly infinite data. For
                  modelling these systems, a UML profile comprising component
                  diagrams, protocol state machines, and class diagrams is used;
                  for specifying the formal semantics of these models, the
                  combination CSP-OZ-DC of CSP (Communicating Sequential
                  Processes), OZ (Object-Z) and DC (Duration Calculus) is
                  employed; for verifying properties of these specifications,
                  translators are provided to the input formats of the model
                  checkers ARMC (Abstraction Refinement Model Checker) and SLAB
                  (Slicing Abstraction model checker) as well as the tool
                  H-PILoT (Hierarchical Proving by Instantiation in Local Theory
                  extensions). The application of the tool is illustrated by a
                  selection of examples that have been successfully analysed
                  with Syspect. },
}


@INCOLLECTION{springerlink:10.1007/978-3-642-14600-8_40,
  AUTHOR = {Linker, Sven},
  AFFILIATION = {Carl von Ossietzky University of Oldenburg},
  TITLE = {Diagrammatic Specification of Mobile Real-Time Systems},
  BOOKTITLE = {Diagrammatic Representation and Inference},
  SERIES = {Lecture Notes in Computer Science},
  EDITOR = {Goel, Ashok and Jamnik, Mateja and Narayanan, N.},
  PUBLISHER = {Springer Berlin / Heidelberg},
  ISBN = {},
  PAGES = {316-318},
  VOLUME = {6170},
  URL = {http://dx.doi.org/10.1007/978-3-642-14600-8_40},
  NOTE = {10.1007/978-3-642-14600-8_40},
  YEAR = {2010}
}


@INPROCEEDINGS{Kem10,
  AUTHOR = {Stephanie Kemper},
  EDITOR = {Dave Clarke and
               Gul A. Agha},
  TITLE = {Compositional Construction of Real-Time Dataflow Networks},
  BOOKTITLE = {Coordination Models and Languages, 12th International Conference,
               COORDINATION 2010, Amsterdam, The Netherlands, June 7-9,
               2010. Proceedings},
  PUBLISHER = {Springer},
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {6116},
  YEAR = {2010},
  PAGES = {92-106},
  DOI = {10.1007/978-3-642-13414-2_7},
  URL = {http://csd.informatik.uni-oldenburg.de/~stephie/Kemper_COORDINATION10.pdf}
}


@BOOK{Platzer10,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Logical Analysis of Hybrid Systems:
               Proving Theorems for Complex Dynamics},
  PUBLISHER = {Springer},
  ADDRESS = {Heidelberg},
  YEAR = {2010},
  ISBN = {978-3-642-14508-7},
  DOI = {10.1007/978-3-642-14509-4},
  URL = {http://symbolaris.com/lahs/}
}


@INPROCEEDINGS{HMO10,
  AUTHOR = {J. Hoenicke and R. Meyer and E.-R. Olderog},
  TITLE = {Kleene, Rabin, and Scott Are Available},
  EDITOR = {Paul Gastin and Fran\c{c}ois Laroussinie},
  BOOKTITLE = {CONCUR 2010 - Concurrency Theory (CONCUR)},
  PUBLISHER = {Springer},
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {6269},
  PAGES = {462-477},
  YEAR = {2010},
  URL = {http://dx.doi.org/10.1007/978-3-642-15375-4_32}
}


@ARTICLE{FrJaLaSa:InfComput10,
  AUTHOR = {Fr\"{o}schle, Sibylle and Jan\v{c}ar, Petr and Lasota, Slawomir and Sawa, Zden\v{e}k},
  TITLE = {Non-interleaving bisimulation equivalences on Basic Parallel Processes},
  JOURNAL = {Inf. Comput.},
  VOLUME = {208},
  NUMBER = {1},
  YEAR = {2010},
  PAGES = {42--62},
  PUBLISHER = {Academic Press, Inc.}
}


@INPROCEEDINGS{Faber2010,
  AUTHOR = {J. Faber},
  TITLE = {{Verification Architectures}: Compositional Reasoning for Real-time
	Systems},
  BOOKTITLE = {Integrated Formal Methods},
  YEAR = {2010},
  EDITOR = {D. M{\'e}ry and S. Merz},
  VOLUME = {6396},
  SERIES = {Lecture Notes in Computer Science},
  PAGES = {136--151},
  PUBLISHER = {Springer, Heidelberg},
  DOI = {10.1007/978-3-642-16265-7_11},
  ABSTRACT = { We introduce a conceptual approach to decompose real-time systems,
	specified by integrated formalisms: instead of showing safety of
	a system directly, one proves that it is an instance of a Verification
	Architecture, a safe behavioural protocol with unknowns and local
	real-time assumptions. We examine how different verification techniques
	can be combined in a uniform framework to reason about protocols,
	assumptions, and instantiations of protocols. The protocols are specified
	in CSP, extended by data and unknown processes with local assumptions
	in a real-time logic. To prove desired properties, the CSP dialect
	is embedded into dynamic logic and a sequent calculus is presented.
	Further, we analyse the instantiation of protocols by combined specifications,
	here illustrated by CSP-OZ-DC. Using an example, we show that this
	approach helps us verify specifications that are too complex for
	direct verification. },
  PDF = {http://csd.informatik.uni-oldenburg.de/~jfaber/dl/IFM2010a.pdf},
  NOTE = {This publication is available at
            \url{http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/978-3-642-16265-7_11}
    {SpringerLink}}
}


@INPROCEEDINGS{FIJ+2010,
  AUTHOR = {J. Faber and C. Ihlemann and S. Jacobs and V. Sofronie-Stokkermans},
  TITLE = {Automatic Verification of Parametric Specifications with Complex
	Topologies},
  SERIES = {Lecture Notes in Computer Science},
  BOOKTITLE = {Integrated Formal Methods},
  YEAR = {2010},
  EDITOR = {D. M{\'e}ry and S. Merz},
  VOLUME = {6396},
  PAGES = {152--167},
  PUBLISHER = {Springer, Heidelberg},
  ABSTRACT = {The focus of this paper is on reducing the complexity in verification
	by exploiting modularity at various levels: in specification, in
	verification, and structurally. For specifications, we use the modular
	language CSP-OZ-DC, which allows us to decouple verification tasks
	concerning data from those concerning durations. At the verification
	level, we exploit modularity in theorem proving for rich data structures
	and use this for invariant checking. At the structural level, we
	analyze possibilities for modular verification of systems consisting
	of various components which interact. We illustrate these ideas by
	automatically verifying safety properties of a case study from the
	European Train Control System standard, which extends previous examples
	by comprising a complex track topology with lists of track segments
	and trains with different routes.},
  PDF = {http://csd.informatik.uni-oldenburg.de/~jfaber/dl/IFM2010b.pdf},
  NOTE = {This publication is available at
            \url{http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/978-3-642-16265-7_12}
    {SpringerLink}},
  DOI = {http://dx.doi.org/10.1007/978-3-642-16265-7_12}
}


@INPROCEEDINGS{OS10,
  AUTHOR = {E.-R. Olderog and M. Swaminathan},
  TITLE = {Layered Composition for Timed Automata},
  EDITOR = {K. Chatterjee and T. A Henzinger},
  BOOKTITLE = {Formal Modeling and Analysis of Timed Systems (FORMATS) },
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {6246},
  PUBLISHER = {Springer-Verlag},
  PAGES = {228-242},
  YEAR = {2010},
  URL = {http://dx.doi.org/10.1007/978-3-642-15297-9_18}
}


@INPROCEEDINGS{MS2010,
  EDITOR = {Tayssir Touili and
               Byron Cook and
               Paul Jackson},
  VOLUME = {6174},
  YEAR = {2010},
  PAGES = {175--179},
  ISBN = {978-3-642-14294-9},
  AUTHOR = {R. Meyer and T. Strazny},
  TITLE = {Petruchio: From dynamic networks to nets},
  BOOKTITLE = {Proceedings of the 22nd International Conference on Computer Aided Verification 2010, CAV 2010},
  SERIES = {LNCS},
  PUBLISHER = {Springer-Verlag},
  ABSTRACT = {We introduce Petruchio, a tool for computing Petri net translations of dynamic networks. To cater for unbounded architectures beyond the capabilities of existing implementations, the principle fixed-point engine runs interleaved with coverability queries. We discuss algorithmic enhancements and provide experimental evidence that Petruchio copes with models of reasonable size.}
}


@INPROCEEDINGS{HOP10,
  AUTHOR = {J. Hoenicke and E.-R. Olderog and A. Podelski},
  TITLE = {Fairness for Dynamic Control},
  EDITOR = {J. Esparza and R. Majumdar },
  BOOKTITLE = {Tools and Algorithms for the Construction and Analysis of Systems (TACAS) },
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {6015},
  PUBLISHER = {Springer-Verlag},
  PAGES = {251--265},
  YEAR = {2010}
}


@INPROCEEDINGS{OlPo10,
  AUTHOR = {E.-R. Olderog and A. Podelski},
  EDITOR = {D. Dams and U. Hannemann and M. Steffen},
  TITLE = { Explicit Fair Scheduling for Dynamic Control },
  BOOKTITLE = {Concurrency, Compositionality, and Correctness },
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {5930 },
  PUBLISHER = {Springer-Verlag },
  PAGES = {96--117 },
  YEAR = {2010}
}


@ARTICLE{Kem09,
  AUTHOR = {Stephanie Kemper},
  TITLE = {{SAT}-based {V}erification for {T}imed {C}omponent {C}onnectors},
  JOURNAL = {Electr. Notes Theor. Comput. Sci.},
  VOLUME = {255},
  YEAR = {2009},
  PAGES = {103-118},
  URL = {http://csd.informatik.uni-oldenburg.de/~stephie/Kemper_FOCLASA09.pdf},
  DOI = {10.1016/j.entcs.2009.10.027},
  KEYWORDS = {Timed Constraint Automata, Abstraction Refinement, Model Checking, SAT, Component-Based Software Engineering}
}


@ARTICLE{FrGo:Express09,
  AUTHOR = {Sibylle B. Fr{\"o}schle and
               Daniele Gorla},
  TITLE = {Proceedings 16th International Workshop on Expressiveness
               in Concurrency},
  JOURNAL = {CoRR},
  VOLUME = {abs/0911.3189},
  YEAR = {2009}
}


@INPROCEEDINGS{CzFrLa:Concur09,
  AUTHOR = {Czerwi\'{n}ski, Wojciech and Fr\"{o}schle, Sibylle and Lasota, S\lawomir},
  TITLE = {Partially-Commutative Context-Free Processes},
  BOOKTITLE = {CONCUR 2009: Proceedings of the 20th International Conference on Concurrency Theory},
  YEAR = {2009},
  PAGES = {259--273},
  PUBLISHER = {Springer-Verlag}
}


@ARTICLE{FrSt:ArspaWits09,
  AUTHOR = {Fr\"{o}schle, Sibylle and Steel, Graham},
  TITLE = {Analysing PKCS\#11 Key Management APIs with Unbounded Fresh Data},
  BOOK = {Foundations and Applications of Security Analysis: Joint Workshop on Automated Reasoning for Security Protocol Analysis and Issues in the Theory of Security, ARSPA-WITS 2009, York, UK, March 28-29, 2009, Revised Selected Papers},
  YEAR = {2009},
  PAGES = {92--106},
  PUBLISHER = {Springer-Verlag}
}


@INPROCEEDINGS{Faber2009,
  AUTHOR = {J. Faber},
  TITLE = {Verification Architectures for Real-time Systems},
  BOOKTITLE = {Proceedings of Formal Methods 2009 Doctoral Symposium},
  YEAR = {2009},
  EDITOR = {M. Mousavi and E. Sekerinski},
  NUMBER = {09-15},
  SERIES = {CS-Report, Eindhoven University of Technology},
  PAGES = {14--19},
  PDF = {http://csd.informatik.uni-oldenburg.de/~jfaber/dl/FM09_DS.pdf},
  URL = {http://alexandria.tue.nl/repository/books/654108.pdf },
  INSTITUTION = {Eindhoven University of Technology},
  TYPE = {CS-Report}
}


@INPROCEEDINGS{ero-rm-09,
  AUTHOR = {E.-R. Olderog and R. Meyer},
  TITLE = {Automata-theoretic verification based on
    counterexample specification},
  EDITOR = {V. Diekert and K. Weicker and N. Weicker},
  BOOKTITLE = {Informatik als Dialog zwischen Theorie und Anwendung},
  YEAR = {2009},
  PAGES = {217--225},
  PUBLISHER = {Vieweg-Teubner},
}


@INPROCEEDINGS{MS09,
  AUTHOR = {M. Fr{\"a}nzle and M. Swaminathan},
  TITLE = {Revisiting Decidability and Optimum Reachability for Multi-Priced Timed Automata},
  EDITOR = {J. Ouaknine and F. Vaandrager},
  BOOKTITLE = {Formal Modeling and Analysis of Timed Systems (FORMATS) },
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {5813},
  PUBLISHER = {Springer-Verlag},
  PAGES = {149-163},
  YEAR = {2009},
  URL = {http://dx.doi.org/10.1007/978-3-642-04368-0_13}
}


@INPROCEEDINGS{DBLP:conf/cade/PlatzerQR09,
  AUTHOR = {Andr{\'e} Platzer and Jan-David Quesel and Philipp R{\"u}mmer},
  TITLE = {Real World Verification},
  BOOKTITLE = {Automated Deduction - CADE-22, 22nd International Conference on Automated Deduction, McGill University, Montreal, Canada, August 2 - 7, 2009, Proceedings},
  EDITOR = {Renate A. Schmidt},
  PUBLISHER = {Springer},
  VOLUME = {5663},
  PAGES = {485-501},
  SERIES = {LNCS},
  YEAR = {2009},
  DOI = {10.1007/978-3-642-02959-2_35},
  PDF = {http://symbolaris.com/pub/rwv.pdf},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-642-02959-2_35}{(c)
Springer-Verlag}},
  ABSTRACT = {Scalable handling of real arithmetic is a crucial part of
			the verification of hybrid systems, mathematical algorithms, and mixed
			analog/digital circuits.  Despite substantial advances in
			verification technology, complexity issues with classical decision
			procedures are still a major obstacle for formal verification of
			real-world applications, e.g., in automotive and avionic
			industries.  To identify strengths and weaknesses, we examine state
			of the art symbolic techniques and implementations for the
			universal fragment of real-closed fields: approaches based on
			quantifier elimination, Gr{\"o}bner Bases, and semidefinite
			programming for the Positivstellensatz.  Within a uniform context
			of the verification tool KeYmaera, we compare these approaches
			qualitatively and quantitatively on verification benchmarks from
			hybrid systems, textbook algorithms, and on geometric problems.
			Finally, we introduce a new decision procedure combining
			Gr{\"o}bner Bases and semidefinite programming for the real
			Nullstellensatz that outperforms the individual approaches on an
			interesting set of problems.}
}


@INPROCEEDINGS{conf/icfem/PlatzerQ09,
  AUTHOR = {Andr{\'e} Platzer and Jan-David Quesel},
  TITLE = {European Train Control System: A Case Study in Formal Verification},
  BOOKTITLE = {Formal Methods and Software Engineering, 11th International Conference
	               on Formal Engineering Methods, ICFEM 2009, Rio de Janeiro, December
	               9-12, 2009, Proceedings},
  EDITOR = {Ana Cavalcanti and Karin Breitman},
  PUBLISHER = {Springer},
  ADDRESS = {Heidelberg},
  SERIES = {LNCS},
  VOLUME = {5885},
  PAGES = {246-265},
  YEAR = {2009},
  DOI = {10.1007/978-3-642-10373-5_13},
  PDF = {http://symbolaris.com/pub/etcs.pdf},
  SLIDES = {http://csd.informatik.uni-oldenburg.de/~jdq/slides/ETCS-slides.pdf},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-642-10373-5_13}{(c) Springer-Verlag}},
  ABSTRACT = {Complex physical systems have several degrees of freedom.
	They only work correctly when their control parameters obey
	corresponding constraints.  Based on the informal specification of
	the European Train Control System (ETCS), we design a controller
	for its cooperation protocol.  For its free parameters, we
	successively identify constraints that are required to ensure
	collision freedom. We formally prove the parameter
	constraints to be sharp by characterizing them equivalently
	in terms of reachability properties of the hybrid system
	dynamics.  Using our deductive verification tool KeYmaera,
	we formally verify controllability, safety, liveness, and
	reactivity properties of the ETCS protocol that entail
	collision freedom.  We prove that the ETCS protocol
	remains correct even in the presence of perturbation by
	disturbances in the dynamics.  Finally we verify that
	safety is preserved when a PI controller is used for
	speed supervision.}
}


@INPROCEEDINGS{sj09,
  AUTHOR = {Sch\"afer, A. and John, M.},
  TITLE = {Conceptional Modeling and Analysis of Spatio-Temporal Processes in
        Biomolecular Systems},
  BOOKTITLE = {Sixth Asia-Pacific Conference on Conceptual Modelling (APCCM 2009),
        Wellington, New Zealand, January 2009},
  EDITOR = {Markus Kirchberg and Sebastian Link},
  SERIES = {CRPIT},
  VOLUME = {96},
  PUBLISHER = {Australian Computer Society},
  YEAR = {2009},
  PAGES = {39--48},
}


@ARTICLE{Fr:Express08,
  AUTHOR = {Fr\"{o}schle, Sibylle},
  TITLE = {Adding Branching to the Strand Space Model},
  JOURNAL = {Electron. Notes Theor. Comput. Sci.},
  VOLUME = {242},
  NUMBER = {1},
  YEAR = {2009},
  PAGES = {139--159},
  PUBLISHER = {Elsevier Science Publishers B. V.}
}


@INPROCEEDINGS{SFK08,
  AUTHOR = {M. Swaminathan and M. Fr{\"a}nzle and J-.P. Katoen},
  TITLE = {The Surprising Robustness of (Closed) Timed Automata against Clock-Drift},
  EDITOR = {Giorgio Ausiello and Juhani Karhum{\"a}ki},
  BOOKTITLE = {IFIP International Conference on Theoretical Computer Science (IFIP TCS) },
  SERIES = {International Federation for Information Processing},
  VOLUME = {273},
  PUBLISHER = {Springer},
  PAGES = {537-553},
  YEAR = {2008},
  URL = {http://dx.doi.org/10.1007/978-0-387-09680-3_36}
}


@BOOK{ABO09-Book3,
  AUTHOR = { K. R. Apt and F. S. de Boer and E.-R. Olderog },
  TITLE = {Verification of Sequential and Concurrent Programs,
                     3rd Edition},
  SERIES = {Texts in Computer Science},
  PUBLISHER = {Springer-Verlag},
  YEAR = {2009},
  NOTE = {502 pp, ISBN 978-1-84882-744-8}
}


@BOOK{OD08,
  AUTHOR = {E.-R. Olderog and H. Dierks},
  TITLE = {Real-Time Systems --- Formal Specification and Automatic 
Verification},
  PUBLISHER = {Cambridge University Press},
  YEAR = 2008,
  NOTE = {ISBN 978-0-521-88333-7. For more information see: 
          \url{http://csd.informatik.uni-oldenburg.de/rt-book/}{http://csd.informatik.uni-oldenburg.de/rt-book/}}
}


@INPROCEEDINGS{Old08,
  AUTHOR = {E.-R. Olderog},
  TITLE = {Automatic Verification of Combined Specifications},
  BOOKTITLE = {Proc. of the 1st Internat. Workshop on Harnessing Theories for
               Tool Support in Software (TTSS 2007), Macau},
  YEAR = {2008},
  EDITOR = {G. Pu and V. Stolz},
  SERIES = {ENTCS},
  JOURNAL = {Electr. Notes Theor. Comput. Sci.},
  ISSN = {1571-0661},
  VOLUME = {207},
  NUMBER = {},
  MONTH = {April},
  PAGES = {3--16},
  EE = {http://dx.doi.org/10.1016/j.entcs.2008.03.082},
  URL = {},
  KEYWORDS = {Real-time systems, complex data,
               CSP, Object-Z, Duration Calculus,
               model checking, abstraction refinement, 
               UML profile, tool support},
  ABSTRACT = { This paper gives an overview of results of the project 
``Beyond Timed Automata'' carried out in the Collaborative Research Center AVACS 
(Automatic Verification and Analysis of Complex Systems) 
of the Universities of Oldenburg, Freiburg, and Saarbr\"ucken.
We discuss how properties of high-level specifications 
of real-time systems combining the dimensions of
process behaviour, data, and time
can be automatically verified, exploiting recent advances
in semantics, constraint-based model checking, and
decision procedures for complex data.

As specification language we consider CS-OZ-DC,
which integrates concepts from 
Communicating Sequential Processes (CSP), Object-Z (OZ),
and Duration Calculus (DC).
Our approach to automatic verification of CSP-OZ-DC rests
on a compositional semantics of this languages in terms of 
Phase-Event-Automata. These can be translated into 
Transition Constraint Systems which serve as an input 
language of an abstract refinement model checker called
ARMC which can handle constraints covering both real-time
and infinite data.
This is demonstrated by a case study concerning emergency
messages in the European Train Control System (ETCS).
For CSP-OZ-DC we also discuss a UML profile and tool support.
 }
}


@ARTICLE{MORW08,
  AUTHOR = {M. M{\"o}ller and E.-R. Olderog and H. Rasch and H.
                 Wehrheim},
  TITLE = {Integrating a Formal Method into a Software
                 Engineering Process with {UML} and {Java}},
  JOURNAL = {Formal Apsects of Computing},
  YEAR = {2008},
  VOLUME = {20},
  PAGES = {161--204},
  ABSTRACT = {We describe how CSP-OZ, a formal method combining the
                 process algebra CSP with the specification language
                 Object-Z, can be integrated into an object-oriented
                 software engineering process employing the UML as a
                 modelling and Java as an implementation language. The
                 benefit of this integration lies in the rigour of the
                 formal method, which improves the precision of the
                 constructed models and opens up the possibility of (1)
                 verifying properties of models in the early design
                 phases, and (2) checking adherence of implementations
                 to models. The envisaged application area of our
                 approach is the design of distributed {\em reactive
                 systems}. To this end, we propose a specific UML {\em
                 profile} for reactive systems. The profile contains
                 facilities for modelling components, their interfaces
                 and interconnections via synchronous/broadcast
                 communication, and the overall architecture of a
                 system. The integration with the formal method proceeds
                 by generating a significant part of the CSP-OZ
                 specification from the initially developed UML model.
                 The formal specification is on the one hand the
                 starting point for {\em verifying} properties of the
                 model, for instance by using the FDR model checker. On
                 the other hand, it is the basis for generating {\em
                 contracts} for the final implementation. Contracts are
                 written in the Java Modeling Language (JML)
                 complemented by \CSPjassda{}, an assertion language for
                 specifying orderings between method invocations. A set
                 of tools for runtime checking can be used to supervise
                 the adherence of the final Java implementation to the
                 generated contracts.},
}


@ARTICLE{schaefer2008,
  AUTHOR = {A. Sch\"afer},
  TITLE = {{Beschreibung und Verifikation r\"aumlicher und zeitlicher Eigenschaften
	mobiler Systeme}},
  JOURNAL = {it -- Information Technology},
  YEAR = {2008},
  VOLUME = {50},
  PAGES = {324-326},
  NUMBER = {5},
  DOI = {DOI 10.1524/itit.2008.0503},
  URL = {http://csd.informatik.uni-oldenburg.de/pub/Papers/itti0805_324a.pdf},
  NOTE = {\url{http://it-Information-Technology.de}{http://it-Information-Technology.de}},
  ABSTRACT = {
This paper provides an overview over a formal method for the analysis of mobile real-time systems. Control systems for cars and trains as well as mobile robots are examples of such systems. We develop a spatio-temporal logic that is used to model both the systems and safety requirements. We investigate the theoretical foundations like decidability and axiomatisability and develop a prototype tool for the automatic verification based on these results. The application of this logic is exemplified with an industrial case study.}
}


@ARTICLE{DBLP:journals/logcom/Platzer08,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Differential-Algebraic Dynamic Logic for Differential-Algebraic Programs},
  JOURNAL = {Journal of Logic and Computation},
  YEAR = {2008},
  NOTE = {Accepted for publication},
  DOI = {10.1093/logcom/exn070},
  PDF = {http://symbolaris.com/pub/DAL.pdf},
  KEYWORDS = {dynamic logic, differential constraints, sequent calculus, verification of hybrid systems, differential induction, theorem proving},
  ABSTRACT = {
      We generalise dynamic logic to a logic for
      differential-algebraic programs, i.e., discrete programs
      augmented with first-order differential-algebraic formulas as
      continuous evolution constraints in addition to first-order
      discrete jump formulas.  These programs characterise interacting
      discrete and continuous dynamics of hybrid systems elegantly and
      uniformly.  For our logic, we introduce a calculus over real
      arithmetic with discrete induction and a new \emph{differential
      induction} with which differential-algebraic programs can be
      verified by exploiting their differential constraints
      algebraically without having to solve them.  We develop the
      theory of differential induction and differential refinement and
      analyse their deductive power.  As a case study, we present
      parametric tangential roundabout maneuvers in air traffic
      control and prove collision avoidance in our calculus.}
}


@ARTICLE{DBLP:journals/jar/Platzer08,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Differential Dynamic Logic for Hybrid Systems.},
  JOURNAL = {Journal of Automated Reasoning},
  YEAR = {2008},
  VOLUME = {41},
  NUMBER = {2},
  PAGES = {143-189},
  DOI = {10.1007/s10817-008-9103-8},
  PDF = {http://symbolaris.com/pub/freedL.pdf},
  NOTE = {\url{http://dx.doi.org/10.1007/s10817-008-9103-8}{(c)
Springer-Verlag}},
  KEYWORDS = {dynamic logic, differential equations, sequent calculus, axiomatisation, automated theorem proving, verification of hybrid systems},
  ABSTRACT = {
      Hybrid systems are models for complex physical systems and are
      defined as dynamical systems with interacting discrete
      transitions and continuous evolutions along differential
      equations.  With the goal of developing a theoretical and
      practical foundation for deductive verification of hybrid
      systems, we introduce a dynamic logic for hybrid programs, which
      is a program notation for hybrid systems.  As a verification
      technique that is suitable for automation, we introduce a free
      variable proof calculus with a novel combination of real-valued
      free variables and Skolemisation for lifting quantifier
      elimination for real arithmetic to dynamic logic.  The calculus
      is compositional, i.e., it reduces properties of hybrid programs
      to properties of their parts.  Our main result proves that this
      calculus axiomatises the transition behaviour of hybrid systems
      completely relative to differential equations.  In a case study
      with cooperating traffic agents of the European Train Control
      System, we further show that our calculus is well-suited for
      verifying realistic hybrid systems with parametric system
      dynamics.
  }
}


@ARTICLE{Meyer2008,
  AUTHOR = {R. Meyer and J. Faber and J. Hoenicke and A. Rybalchenko},
  TITLE = {Model Checking Duration Calculus: A Practical Approach},
  JOURNAL = {Formal Aspects of Computing},
  YEAR = {2008},
  PUBLISHER = {Springer London},
  VOLUME = {20},
  PAGES = {481--505},
  NUMBER = {4--5},
  MONTH = JUL,
  NOTE = {{ISSN} 0934-5043 (Print) 1433-299X (Online)},
  ABSTRACT = {Model checking of real-time systems against Duration Calculus (DC)
	specifications requires the translation of DC formulae into automata-based
	semantics. The existing algorithms provide a limited DC coverage
	and do not support compositional verification. We propose a translation
	algorithm that advances the applicability of model checking tools
	to realistic applications. Our algorithm significantly extends the
	subset of DC that can be checked automatically. The central part
	of the algorithm is the automatic decomposition of DC specifications
	into sub-properties that can be verified independently. The decomposition
	is based on a novel distributive law for DC. We implemented the algorithm
	in a tool chain for the automated verification of systems comprising
	data, communication, and real-time aspects. We applied the tool chain
	to verify safety properties in an industrial case study from the
	European Train Control System (ETCS).},
  DOI = {10.1007/s00165-008-0082-7},
  ISSN = {0934-5043},
  KEYWORDS = {Model checking, Verification, Duration Calculus, Timed automata, Real-time
	systems, European Train Control System, Case study},
  URL = {http://www.springerlink.com/content/81g876074077601g/fulltext.pdf},
}


@INPROCEEDINGS{DBLP:conf/cade/PlatzerQ08,
  AUTHOR = {Andr{\'e} Platzer and
               Jan-David Quesel},
  TITLE = {{KeYmaera}: A Hybrid Theorem Prover for Hybrid Systems.},
  BOOKTITLE = {Automated Reasoning, Fourth International Joint Conference,
               IJCAR 2008, Sydney, Australia, Proceedings},
  YEAR = {2008},
  PAGES = {171-178},
  EDITOR = {Alessandro Armando and
               Peter Baumgartner and
               Gilles Dowek},
  PUBLISHER = {Springer},
  SERIES = {LNCS},
  VOLUME = {5195},
  DOI = {10.1007/978-3-540-71070-7_15},
  ISBN = {10.1007/978-3-540-71070-7_15},
  ISSN = {0302-9743},
  KEYWORDS = {dynamic logic, automated theorem proving, decision procedures, computer algebra, verification of hybrid systems},
  ABSTRACT = {
      KeYmaera is a hybrid verification tool for hybrid systems that
      combines deductive, real algebraic, and computer algebraic
      prover technologies.  It is an automated and interactive theorem
      prover for a natural specification and verification logic for
      hybrid systems.  KeYmaera supports differential dynamic logic,
      which is a real-valued first-order dynamic logic for hybrid
      programs, a program notation for hybrid automata.  For
      automating the verification process, KeYmaera implements a
      generalized free-variable sequent calculus and automatic proof
      strategies that decompose the hybrid system specification
      symbolically.  To overcome the complexity of real arithmetic, we
      integrate real quantifier elimination following an iterative
      background closure strategy.  Our tool is particularly suitable
      for verifying parametric hybrid systems and has been used
      successfully for verifying collision avoidance in case studies
      from train control and air traffic management.},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-71070-7_15}{(c)
Springer-Verlag}},
  URL = {http://symbolaris.com/pub/KeYmaera.pdf},
  SLIDES = {http://csd.informatik.uni-oldenburg.de/~jdq/slides/keymaera-slides.pdf}
}


@INPROCEEDINGS{DBLP:conf/cav/PlatzerC08,
  AUTHOR = {Andr{\'e} Platzer and
               Edmund M. Clarke},
  TITLE = {Computing Differential Invariants of Hybrid Systems as Fixedpoints},
  YEAR = {2008},
  MONTH = {},
  EDITOR = {Aarti Gupta and
               Sharad Malik},
  BOOKTITLE = {Computer-Aided Verification, CAV 2008, Princeton, USA, Proceedings},
  PUBLISHER = {Springer},
  SERIES = {LNCS},
  PAGES = {176-189},
  VOLUME = {5123},
  ISBN = {},
  DOI = {10.1007/978-3-540-70545-1_17},
  KEYWORDS = {verification of hybrid systems, differential invariants, verification logic, fixedpoint engine},
  ABSTRACT = {
      We introduce a fixedpoint algorithm for verifying safety
      properties of hybrid systems with differential equations whose
      right-hand sides are polynomials in the state variables.  In
      order to verify nontrivial systems without solving their
      differential equations and without numerical errors, we use a
      continuous generalization of induction, for which our algorithm
      computes the required differential invariants.  As a means for
      combining local differential invariants into global system
      invariants in a sound way, our fixedpoint algorithm works with a
      compositional verification logic for hybrid systems.  To improve
      the verification power, we further introduce a saturation
      procedure that refines the system dynamics successively with
      differential invariants until safety becomes provable.  By
      complementing our symbolic verification algorithm with a robust
      version of numerical falsification, we obtain a fast and sound
      verification procedure.  We verify roundabout maneuvers in air
      traffic management and collision avoidance in train control.},
  PDF = {http://symbolaris.com/pub/fpdi.pdf},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-70545-1_17}{(c)
Springer-Verlag}}
}


@INPROCEEDINGS{Meyer2008BoundedDepth,
  AUTHOR = {R. Meyer},
  TITLE = {On Boundedness in Depth in the $\pi$-Calculus},
  BOOKTITLE = {Proc. of the 5th IFIP International
Conference on Theoretical Computer Science, IFIP TCS 2008},
  SERIES = {IFIP},
  VOLUME = {273},
  PUBLISHER = {Springer-Verlag},
  YEAR = {2008},
  PAGES = {},
  NOTE = {To appear},
  KEYWORDS = {$\pi$-Calculus, structural congruence, well-structured transition
systems, termination},
  ABSTRACT = {
We investigate the class $P_{\mathit{BD}}$ of $\pi$-Calculus processes that are
bounded in the function depth. First, we show that boundedness in depth has an
intuitive characterisation when we understand processes as graphs: a process is
bounded in depth if and only if the length of the simple paths is bounded. The
proof is based on a new normal form for the $\pi$-Calculus called anchored
fragments. Using this concept, we then show that processes of bounded depth have
well-structured transition systems (WSTS). As a consequence, the termination
problem is decidable for this class of processes. The instantiation of the WSTS
framework employs a new well-quasi-ordering for processes in $P_{\mathit{BD}}$.}
}


@ARTICLE{MeyerKhomenkoStrazny2009Unfolding,
  AUTHOR = {R. Meyer and V. Khomenko and T. Strazny},
  TITLE = {A Practical Approach to Verification of Mobile Systems Using Net Unfoldings},
  JOURNAL = {Fundamenta Informaticae},
  PUBLISHER = {IOS Press},
  NOTE = {Special Issue on Petri Nets 2008, invited version of the ATPN 2008 paper},
  VOLUME = {94},
  NUMBER = {3--4},
  PAGES = {439--471},
  YEAR = {2009},
  KEYWORDS = {finite control processes, safe processes, $\pi$-Calculus, mobile
systems, model checking, Petri net unfoldings},
  ABSTRACT = {
We propose a technique for verification of mobile systems. We
translate \emph{finite control processes,} which are a
well-known subset of \picalc, into Petri nets, which are
subsequently used for model checking. This translation always
yields bounded Petri nets with a small bound, and we develop a
technique for computing a non-trivial bound by static analysis.
Moreover, we introduce the notion of \emph{safe processes,}
which are a subset of finite control processes, for which our
translation yields safe Petri nets, and show that every finite
control process can be translated into a safe one of at most
quadratic size. This gives a possibility to translate every
finite control process into a safe Petri net, for which
efficient unfolding-based verification is possible. Our
experiments show that this approach has a significant advantage
over other existing tools for verification of mobile systems in
terms of memory consumption and runtime. We also demonstrate
the applicability of our method on a realistic model of an
automated manufacturing system.}
}


@INPROCEEDINGS{MeyerKhomenkoStrazny2008Unfolding,
  AUTHOR = {R. Meyer and V. Khomenko and T. Strazny},
  TITLE = {A Practical Approach to Verification of Mobile Systems Using Net Unfoldings},
  BOOKTITLE = {Proc. of the 29th International Conference on Application and Theory of Petri Nets and Other Models of Concurrency, ATPN 2008},
  SERIES = {LNCS},
  VOLUME = {5062},
  PUBLISHER = {Springer-Verlag},
  PAGES = {327--347},
  YEAR = {2008},
  KEYWORDS = {finite control processes, safe processes, $\pi$-Calculus, mobile
systems, model checking, Petri net unfoldings},
  ABSTRACT = {
In this paper we propose a technique for verification of mobile
systems.We translate finite control processes, which are a well-known
subset of $\pi$-Calculus, into Petri nets, which are subsequently used for
model checking. This translation always yields bounded Petri nets with
a small bound, and we develop a technique for computing a non-trivial
bound by static analysis. Moreover, we introduce the notion of safe pro-
cesses, which are a subset of finite control processes, for which our
translation
yields safe Petri nets, and show that every finite control process can
be translated into a safe one of at most quadratic size. This gives a
possibility
to translate every finite control process into a safe Petri net, for
which efficient unfolding-based verification is possible. Our experiments
show that this approach has a significant advantage over other existing
tools for verification of mobile systems in terms of memory consumption
and runtime.}
}


@INPROCEEDINGS{DBLP:conf/hybrid/PlatzerQ08,
  AUTHOR = {Andr{\'e} Platzer and
               Jan-David Quesel},
  TITLE = {Logical Verification and Systematic Parametric Analysis in
Train Control.},
  YEAR = {2008},
  PAGES = {646-649},
  DOI = {10.1007/978-3-540-78929-1_55},
  EDITOR = {Magnus Egerstedt and
               Bud Mishra},
  BOOKTITLE = {Hybrid Systems: Computation and Control, 10th International
               Conference, HSCC 2008, St. Louis, USA, Proceedings},
  PUBLISHER = {Springer},
  SERIES = {LNCS},
  VOLUME = {4981},
  ISBN = {},
  KEYWORDS = {parametric verification, logic for hybrid systems, symbolic
decomposition},
  ABSTRACT = {
      We formally verify hybrid safety properties of cooperation
      protocols in a fully parametric version of the European Train
      Control System (ETCS). We present a formal model using hybrid
      programs and verify correctness using our logic-based
      decomposition procedure. This procedure supports free parameters
      and parameter discovery, which is required to determine correct
      design choices for free parameters of ETCS.},
  URL = {http://symbolaris.com/pub/ETCS-short.pdf},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-78929-1_55}{(c)
Springer-Verlag}}
}


@INPROCEEDINGS{Meyer2007Dagstuhl,
  AUTHOR = {R. Meyer},
  TITLE = {{A Petri Net Semantics for $\pi$-Calculus Verification}},
  BOOKTITLE = {Dagstuhl ''zehn plus eins''},
  PAGES = {76--77},
  YEAR = {2007},
  PUBLISHER = {Verlagshaus Mainz GmbH Aachen},
}


@ARTICLE{FrLa:TCS07,
  AUTHOR = {Sibylle Fr{\"o}schle and S{\l}awomir Lasota},
  TITLE = {Causality versus true-concurrency},
  JOURNAL = {Theoretical Computer Science},
  YEAR = {2007},
  VOLUME = {386},
  NUMBER = {3},
  PAGES = {169--187},
}


@ARTICLE{AVACS07,
  AUTHOR = {B. Becker and A. Podelski and W. Damm and M. Fr{\"a}nzle and
                  E.-R. Olderog and R. Wilhelm},
  TITLE = {{SFB/TR 14 AVACS -- Automatic Verification and Analysis of 
Complex Systems}},
  JOURNAL = {it -- Information Technology},
  PUBLISHER = {Oldenbourg},
  YEAR = {2007},
  NUMBER = {2},
  VOLUME = {49},
  PAGES = {118--126},
  NOTE = {See also \url{http://www.avacs.org}{http://www.avacs.org}}
}


@ARTICLE{sch07b,
  AUTHOR = {A. Sch\"afer},
  TITLE = {{PhD Abstract: Specification and Verification of Mobile Real-Time
Systems}},
  EDITOR = {V. Sassone},
  YEAR = {2007},
  PAGES = {193-195},
  PUBLISHER = {EATCS},
  JOURNAL = {Bulletin of the EATCS},
  VOLUME = {92},
  URL = {http://csd.informatik.uni-oldenburg.de/pub/Papers/as07b.pdf}
}


@INPROCEEDINGS{sch07a,
  AUTHOR = {A. Sch\"afer},
  TITLE = {{Spezifikation und Verifikation mobiler Realzeitsysteme}},
  BOOKTITLE = {{Ausgezeichnete Informatikdissertationen 2007}},
  EDITOR = {D. Wagner},
  YEAR = {2007},
  PAGES = {169-177},
  SERIES = {GI-Edition-Lecture Notes in Informatics (LNI)},
  PUBLISHER = {Gesellschaft f\"ur Informatik},
  URL = {http://csd.informatik.uni-oldenburg.de/pub/Papers/as07a.pdf}
}


@INPROCEEDINGS{DBLP:conf/verify/Platzer07,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Combining Deduction and Algebraic Constraints for Hybrid System
Analysis.},
  BOOKTITLE = {4th International Verification Workshop, VERIFY'07, Workshop at
Conference on Automated Deduction (CADE), Bremen, Germany},
  YEAR = {2007},
  PAGES = {164-178},
  EDITOR = {Bernhard Beckert},
  VOLUME = {259},
  PUBLISHER = {CEUR-WS.org},
  SERIES = {},
  NOTE = {\url{http://ceur-ws.org/Vol-259}{CEUR Workshop Proceedings}},
  ISSN = {1613-0073},
  KEYWORDS = {modular prover combination, analytic tableaux, verification of
hybrid systems, dynamic logic},
  ABSTRACT = {
      We show how theorem proving and methods for handling real
      algebraic constraints can be combined for hybrid system
      verification.  In particular, we highlight the interaction of
      deductive and algebraic reasoning that is used for handling the
      joint discrete and continuous behaviour of hybrid systems.  We
      illustrate proof tasks that occur when verifying scenarios with
      cooperative traffic agents.  From the experience with these
      examples, we analyse proof strategies for dealing with the
      practical challenges for integrated algebraic and deductive
      verification of hybrid systems, and we propose an iterative
      background closure strategy.},
  URL = {http://symbolaris.com/pub/cdachsa.pdf}
}


@INPROCEEDINGS{DammMOOPPSW07,
  AUTHOR = {Werner Damm and Alfred Mikschl and Jens Oehlerking and
Ernst-R{\"u}diger Olderog and Jun Pang and Andr{\'e} Platzer and Marc 
Segelken and Boris Wirtz},
  TITLE = {Automating Verification of Cooperation, Control, and Design in
Traffic Applications.},
  YEAR = {2007},
  PAGES = {115--169},
  EDITOR = {Cliff Jones and Zhiming Liu and Jim Woodcock},
  BOOKTITLE = {Formal Methods and Hybrid Real-Time Systems},
  PUBLISHER = {Springer-Verlag},
  SERIES = {LNCS},
  VOLUME = {4700},
  DOI = {10.1007/978-3-540-75221-9_6},
  ISSN = {},
  KEYWORDS = {},
  ABSTRACT = {
      We present a verification methodology for cooperating traffic
      agents covering analysis of cooperation strategies, realization
      of strategies through control, and implementation of control.
      For each layer, we provide dedicated approaches to formal
      verification of safety and stability properties of the design.
      The range of employed verification techniques invoked to span
      this verification space includes application of pre-verified
      design patterns, automatic synthesis of Lyapunov functions,
      constraint generation for parameterized designs, model-checking
      in rich theories, and abstraction refinement.  We illustrate
      this approach with a variant of the European Train Control
      System (ETCS), employing layer specific verification techniques
      to layer specific views of an ETCS design.},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-75221-9_6}{(c)
Springer-Verlag}}
}


@INPROCEEDINGS{BSO07,
  AUTHOR = {D. Basin and E.-R. Olderog and P.E. Sevin\c{c}},
  TITLE = {Specifying and analyzing security automata using {CSP-OZ}},
  BOOKTITLE = {Proceedings of the 2007 ACM Symposium on Information, Computer
and Communications Security (ASIACCS 2007)},
  PAGES = {70--81},
  YEAR = 2007,
  MONTH = {March},
  PUBLISHER = {ACM Press},
  LOCATION = {Singapore},
  ABSTRACT = {
    Security automata are a variant of B\"uchi automata used to specify
    security policies that can be enforced by monitoring system execution.
    In this paper, we propose using CSP-OZ, a specification language
    combining Communicating Sequential Processes (CSP) and Object-Z (OZ), to
    specify security automata, formalize their combination with target
    systems, and analyze the security of the resulting system
    specifications.  We provide theoretical results relating CSP-OZ
    specifications and security automata and show how
    refinement can be used to reason about specifications of security
    automata and their combination with target systems.  Through a case
    study, we provide evidence for the practical usefulness of this approach.
    This includes the ability to specify concisely complex operations and
    complex control, support for structured specifications, refinement, and
    transformational design, as well as automated, tool-supported analysis.
   }
}


@INPROCEEDINGS{Froeschle:CSF07,
  AUTHOR = {Sibylle Fr{\"o}schle},
  TITLE = {The Insecurity Problem: tackling Unbounded Data},
  BOOKTITLE = {IEEE Computer Security Foundations Symposium 2007},
  YEAR = {2007},
  PUBLISHER = {IEEE Computer Society},
  ABSTRACT = {
In this paper we focus on tackling the insecurity problem of
security protocols in the presence of an unbounded number of data
such as nonces or session keys. First, we pinpoint four open
problems in this category. The first two problems concern protocols
with natural restrictions that any `realistic' protocol should
satisfy while the second two concern protocols with disequality
constraints. For protocols with disequality constraints we will
prove: (1)~Insecurity is decidable in NEXPTIME when bounding the
size of messages and not requiring data to be \emph{freshly}
generated. (2)~Insecurity is NEXPTIME-complete when bounding the
size of messages and the number of freshly generated data used in
honest sessions. This shows that unbounded data can be tackled in
settings which do not trivially reduce to the case of bounded data.
The second result is in contrast with a recently published proof,
which appears to prove the same problem undecidable. We will point
out why this proof cannot be considered to be valid.
},
}


@INPROCEEDINGS{DBLP:conf/tableaux/Platzer07,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Differential Dynamic Logic for Verifying Parametric Hybrid
Systems.},
  PAGES = {216-232},
  DOI = {10.1007/978-3-540-73099-6_17},
  KEYWORDS = {dynamic logic, sequent calculus, verification of parametric
hybrid systems, quantifier elimination},
  ABSTRACT = {
      We introduce a first-order dynamic logic for reasoning about
      systems with discrete and continuous state transitions, and we
      present a sequent calculus for this logic.  As a uniform model,
      our logic supports hybrid programs with discrete and
      differential actions.  For handling real arithmetic during
      proofs, we lift quantifier elimination to dynamic logic.  To
      obtain a modular combination, we use side deductions for
      verifying interacting dynamics.  With this, our logic supports
      deductive verification of hybrid systems with symbolic
      parameters and first-order definable flows.  Using our calculus,
      we prove a parametric inductive safety constraint for speed
      supervision in a train control system.},
  BOOKTITLE = {Automated Reasoning with Analytic Tableaux and Related Methods,
International
               Conference, TABLEAUX 2007, Aix en Provence, France, July 3-6,
2007, Proceedings},
  YEAR = {2007},
  EDITOR = {Nicola Olivetti},
  VOLUME = {4548},
  SERIES = {LNCS},
  PUBLISHER = {Springer-Verlag},
  ISBN = {},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-73099-6_17}{(c)
Springer-Verlag}},
  URL = {http://symbolaris.com/pub/dL.pdf}
}


@INPROCEEDINGS{FJSS07,
  AUTHOR = {J. Faber and S. Jacobs and V. Sofronie-Stokkermans},
  TITLE = {Verifying {CSP-OZ-DC} Specifications with Complex Data Types and
	Timing Parameters},
  BOOKTITLE = {Integrated Formal Methods},
  YEAR = {2007},
  EDITOR = {J. Davies and J. Gibbons},
  VOLUME = {4591},
  SERIES = {Lecture Notes in Computer Science},
  PAGES = {233--252},
  PUBLISHER = {Springer-Verlag},
  MONTH = JUL,
  ABSTRACT = {We extend existing verification methods for CSP-OZ-DC to
	reason about real-time systems with complex data types and timing
	parameters.
	We show that important properties of systems can be encoded
	in well-behaved logical theories in which hierarchical reasoning is
	possible.
	Thus, testing invariants and bounded model checking can be reduced
	to checking satisfiability of ground formulae over a simple base theory.
	We illustrate the ideas by means of a simplified version of a case
	study from the European Train Control System standard.},
  URL = {http://csd.informatik.uni-oldenburg.de/~jfaber/dl/FaberJacobsSofronie.pdf}
}


@INPROCEEDINGS{ib07ifm,
  AUTHOR = {I. Br{\"u}ckner},
  TITLE = {{Slicing Concurrent Real-Time System Specifications for
Verification}},
  BOOKTITLE = {Integrated Formal Methods},
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {4591},
  PUBLISHER = {Springer-Verlag},
  ISSN = {0302-9743},
  ISBN = {978-3-540-73209-9},
  EDITOR = {J. Davies and J. Gibbons},
  PAGES = {54--74},
  MONTH = JUL,
  YEAR = {2007},
  ABSTRACT = {
    The high-level specification language CSP-OZ-DC has been shown to
    be well-suited for modelling and analysing industrially relevant
    concurrent real-time systems.  It allows to model each of the most
    important functional aspects such as control flow, data, and
    real-time requirements in adequate notations, maintaining a common
    semantical foundation for subsequent verification.  Slicing on the
    other hand has become an established technique to complement the
    fight against state space explosion during verification which
    inherently accompanies increasing system complexity.  In this
    paper, we exploit the special structure of CSP-OZ-DC
    specifications by extending the dependence graph---which usually
    serves as a basis for slicing---with several new types of
    dependencies, including timing dependencies derived from the
    specification's DC part.  Based on this we show how to compute a
    specification slice and prove correctness of our approach.
},
  URL = {http://csd.informatik.uni-oldenburg.de/pub/Papers/ib07ifm.pdf}
}


@INPROCEEDINGS{BDFW07,
  AUTHOR = {I. Br\"uckner and K. Dr\"ager and B. Finkbeiner and H. Wehrheim},
  TITLE = {{Slicing Abstractions}},
  BOOKTITLE = {FSEN 2007: IPM International Symposium on Fundamentals of 
              Software Engineering},
  SERIES = {Lecture Notes in Computer Science},
  VOLUME = {4767},
  PUBLISHER = {Springer},
  ISSN = {},
  ISBN = {978-3-540-75697-2},
  EDITOR = {F. Arbab and M. Sirjani},
  PAGES = {17--32},
  MONTH = {April},
  YEAR = {2007},
  ABSTRACT = {
    Abstraction and slicing are both techniques for reducing the size
    of the state space to be inspected during verification.  In this
    paper, we present a new model checking procedure for
    infinite-state concurrent systems that interleaves automatic
    abstraction refinement, which splits states according to new
    predicates obtained by Craig interpolation, with slicing, which
    removes irrelevant states and transitions from the
    abstraction. The effects of abstraction and slicing complement
    each other. As the refinement progresses, the increasing accuracy
    of the abstract model allows for a more precise slice; the
    resulting smaller representation gives room for additional
    predicates in the abstraction. The procedure terminates when an
    error path in the abstraction can be concretized, which proves
    that the system is erroneous, or when the slice becomes empty,
    which proves that the system is correct.
},
  URL = {http://csd.informatik.uni-oldenburg.de/pub/Papers/ib07fsen.pdf}
}


@INPROCEEDINGS{DBLP:conf/lfcs/Platzer07,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {A Temporal Dynamic Logic for Verifying Hybrid System
Invariants.},
  EDITOR = {S. Artemov and A. Nerode},
  DOI = {10.1007/978-3-540-72734-7_32},
  BOOKTITLE = {Logical Foundations of Computer Science, International
               Symposium, LFCS 2007, New York, USA,
               Proceedings},
  PUBLISHER = {Springer},
  SERIES = {LNCS},
  YEAR = {2007},
  PAGES = {457--471},
  VOLUME = {4514},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-72734-7_32}{(c)
Springer-Verlag}},
  URL = {http://symbolaris.com/pub/dTL.pdf},
  KEYWORDS = {dynamic logic, sequent calculus, logic for hybrid systems, 
               temporal logic, deductive verification of embedded systems},
  ABSTRACT = {
    We combine first-order dynamic logic for reasoning about possible
    behaviour of hybrid systems with temporal logic for reasoning
    about the temporal behaviour during their operation.  Our logic
    supports verification of hybrid programs with first-order
    definable flows and provides a uniform treatment of discrete and
    continuous evolution.  For our combined logic, we generalise the
    semantics of dynamic modalities to refer to hybrid traces instead
    of final states. Further, we prove that this gives a conservative
    extension of dynamic logic.  On this basis, we provide a modular
    verification calculus that reduces correctness of temporal
    behaviour of hybrid systems to non-temporal reasoning.  Using this
    calculus, we analyse safety invariants in a train control system
    and symbolically synthesise parametric safety constraints.
  }
}


@INPROCEEDINGS{DBLP:conf/hybrid/Platzer07,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Differential Logic for Reasoning about Hybrid Systems.},
  YEAR = {2007},
  EDITOR = {A. Bemporad and A. Bicchi and G. Buttazzo},
  BOOKTITLE = {Hybrid Systems: Computation and Control, 10th International
               Conference, HSCC 2007, Pisa, Italy, Proceedings},
  PUBLISHER = {Springer-Verlag},
  SERIES = {LNCS},
  PAGES = {746--749},
  DOI = {10.1007/978-3-540-71493-4_75},
  VOLUME = {4416},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-71493-4_75}{(c)
Springer-Verlag}},
  URL = {http://symbolaris.com/pub/dL-short.pdf},
  KEYWORDS = {dynamic logic, hybrid systems, parametric verification},
  ABSTRACT = {
    We propose a first-order dynamic logic for reasoning about hybrid
    systems. As a uniform model for discrete and continuous evolutions
    in hybrid systems, we introduce hybrid programs with differential
    actions. Our logic can be used to specify and verify correctness
    statements about hybrid programs, which are suitable for symbolic
    processing by calculus rules. Using first-order variables, our
    logic supports systems with symbolic parameters. With dynamic
    modalities, it is prepared to handle multiple system components.
  }
}


@INPROCEEDINGS{DBLP:conf/hybrid/PlatzerC07,
  AUTHOR = {Andr{\'e} Platzer and Edmund M. Clarke},
  TITLE = {The Image Computation Problem in Hybrid Systems Model Checking.},
  YEAR = {2007},
  DOI = {10.1007/978-3-540-71493-4_37},
  EDITOR = {A. Bemporad and A. Bicchi and G. Buttazzo},
  BOOKTITLE = {Hybrid Systems: Computation and Control, 10th International
               Conference, HSCC 2007, Pisa, Italy, Proceedings},
  PUBLISHER = {Springer-Verlag},
  SERIES = {LNCS},
  PAGES = {473--486},
  VOLUME = {4416},
  KEYWORDS = {model checking, hybrid systems, image computation},
  NOTE = {\url{http://dx.doi.org/10.1007/978-3-540-71493-4_37}{(c)
Springer-Verlag}},
  URL = {http://symbolaris.com/pub/happroximation.pdf},
  ABSTRACT = {
    In this paper, we analyze limits of approximation techniques for
    (non-linear) continuous image computation in model checking hybrid
    systems. In particular, we show that even a single step of
    continuous image computation is not semidecidable numerically even
    for a very restricted class of functions. Moreover, we show that
    symbolic insight about derivative bounds provides sufficient
    additional information for approximation refinement model
    checking. Finally, we prove that purely numerical algorithms can
    perform continuous image computation with arbitrarily high
    probability. Using these results, we analyze the prerequisites for
    a safe operation of the roundabout maneuver in air traffic
    collision avoidance.
  }
}


@ARTICLE{schaefer07,
  AUTHOR = {A. Sch\"afer},
  TITLE = {Axiomatisation and Decidability of Multi-Dimensional Duration
Calculus},
  JOURNAL = {TIME'05 special issue of Information and Computation},
  YEAR = {2007},
  VOLUME = {205},
  NUMBER = {1},
  NOTE = {DOI
    \url{http://dx.doi.org/10.1016/j.ic.2006.08.005}{10.1016/j.ic.2006.08.005}
  },
  ABSTRACT = {
    The Shape Calculus is a spatio-temporal logic based on an
    $n$-dimensional Duration Calculus tailored for the specification
    and verification of mobile real-time systems.  After showing
    non-axiomatisability, we give a complete embedding in
    $n$-dimensional interval temporal logic and present two different
    decidable subsets, which are important for tool support and
    practical use.
  }
}


@INPROCEEDINGS{DBLP:journals/entcs/KemperP07,
  AUTHOR = {Stephanie Kemper and Andr{\'e} Platzer},
  TITLE = {SAT-based Abstraction Refinement for Real-time Systems},
  BOOKTITLE = {Formal Aspects of Component Software, Third International 
               Workshop, FACS 2006, Prague, Czech Republic, Proceedings},
  YEAR = {2007},
  EDITOR = {Frank S. de Boer and Vladimir Mencl},
  JOURNAL = {Electr. Notes Theor. Comput. Sci.},
  VOLUME = {182},
  SERIES = {ENTCS},
  ISSN = {1571-0661},
  PAGES = {107-122},
  DOI = {10.1016/j.entcs.2006.09.034},
  URL = {http://symbolaris.com/pub/SAAtRe.pdf},
  KEYWORDS = {abstraction refinement, model checking, real-time systems, 
              SAT, Craig interpolation},
  ABSTRACT = {     
    In this paper, we present an abstraction refinement approach for
    model checking safety properties of real-time systems using
    SAT-solving. With a faithful embedding of bounded model checking
    for systems of timed automata into propositional logic and linear
    arithmetic, we achieve both, quick abstraction techniques and a
    linear-size representation of parallel composition. In this
    logical setting, we introduce an abstraction that works uniformly
    for clocks, events, and states. When necessary, abstractions are
    refined by analysing spurious counterexamples using a promising
    extension of counterexample-guided abstraction refinement with
    syntactic information about Craig interpolants. To support
    generalisations, our overall approach identifies the algebraic and
    logical principles required for logic-based abstraction
    refinement.
  }
}


@ARTICLE{FrLa:Infinity06,
  AUTHOR = {Fr\"{o}schle, Sibylle and Lasota, S\lawomir},
  TITLE = {Normed Processes, Unique Decomposition, and Complexity of Bisimulation Equivalences},
  JOURNAL = {Electron. Notes Theor. Comput. Sci.},
  VOLUME = {239},
  YEAR = {2009},
  PAGES = {17--42},
  PUBLISHER = {Elsevier Science Publishers B. V.}
}


@INPROCEEDINGS{DBLP:journals/entcs/Platzer07,
  AUTHOR = {Andr{\'e} Platzer},
  TITLE = {Towards a Hybrid Dynamic Logic for Hybrid Dynamic Systems},
  BOOKTITLE = {Proc., LICS International Workshop on Hybrid Logic, HyLo 
              2006, Seattle, USA},
  YEAR = {2007},
  EDITOR = {Patrick Blackburn and Thomas Bolander and Torben Bra\"{u}ner 
            and Valeria de Paiva and J{\o}rgen Villadsen},
  SERIES = {ENTCS},
  JOURNAL = {Electr. Notes Theor. Comput. Sci.},
  ISSN = {1571-0661},
  VOLUME = {174},
  NUMBER = {6},
  MONTH = {Jun},
  PAGES = {63-77},
  DOI = {10.1016/j.entcs.2006.11.026},
  URL = {http://symbolaris.com/pub/hdL.pdf},
  KEYWORDS = {hybrid logic, dynamic logic, sequent calculus, compositional 
              verification, real-time hybrid dynamic systems},
  ABSTRACT = { 
    We introduce a hybrid variant of a dynamic logic with continuous
    state transitions along differential equations, and we present a
    sequent calculus for this extended hybrid dynamic logic. With the
    addition of satisfaction operators, this hybrid logic provides
    improved system introspection by referring to properties of states
    during system evolution. In addition to this, our calculus
    introduces state-based reasoning as a paradigm for delaying
    expansion of transitions using nominals as symbolic state
    labels. With these extensions, our hybrid dynamic logic advances
    the capabilities for compositional reasoning about (semialgebraic)
    hybrid dynamic systems. Moreover, the constructive reasoning
    support for goal-oriented analytic verification of hybrid dynamic
    systems carries over from the base calculus to our extended
    calculus. 
  }
}