TY - THES AU - Walther, Sven ID - 707 TI - Knowledge-based Verification of Service Compositions ER - TY - CONF AB - Today, software verification tools have reached the maturity to be used for large scale programs. Different tools perform differently well on varying code. A software developer is hence faced with the problem of choosing a tool appropriate for her program at hand. A ranking of tools on programs could facilitate the choice. Such rankings can, however, so far only be obtained by running all considered tools on the program.In this paper, we present a machine learning approach to predicting rankings of tools on programs. The method builds upon so-called label ranking algorithms, which we complement with appropriate kernels providing a similarity measure for programs. Our kernels employ a graph representation for software source code that mixes elements of control flow and program dependence graphs with abstract syntax trees. Using data sets from the software verification competition SV-COMP, we demonstrate our rank prediction technique to generalize well and achieve a rather high predictive accuracy (rank correlation > 0.6). AU - Czech, Mike AU - Hüllermeier, Eyke AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ID - 71 T2 - Proceedings of the 3rd International Workshop on Software Analytics TI - Predicting Rankings of Software Verification Tools ER - TY - GEN AB - Software verification competitions, such as the annual SV-COMP, evaluate software verification tools with respect to their effectivity and efficiency. Typically, the outcome of a competition is a (possibly category-specific) ranking of the tools. For many applications, such as building portfolio solvers, it would be desirable to have an idea of the (relative) performance of verification tools on a given verification task beforehand, i.e., prior to actually running all tools on the task.In this paper, we present a machine learning approach to predicting rankings of tools on verification tasks. The method builds upon so-called label ranking algorithms, which we complement with appropriate kernels providing a similarity measure for verification tasks. Our kernels employ a graph representation for software source code that mixes elements of control flow and program dependence graphs with abstract syntax trees. Using data sets from SV-COMP, we demonstrate our rank prediction technique to generalize well and achieve a rather high predictive accuracy. In particular, our method outperforms a recently proposed feature-based approach of Demyanova et al. (when applied to rank predictions). AU - Czech, Mike AU - Hüllermeier, Eyke AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ID - 72 TI - Predicting Rankings of Software Verification Competitions ER - TY - JOUR AB - Proof-carrying hardware (PCH) is a principle for achieving safety for dynamically reconfigurable hardware systems. The producer of a hardware module spends huge effort when creating a proof for a safety policy. The proof is then transferred as a certificate together with the configuration bitstream to the consumer of the hardware module, who can quickly verify the given proof. Previous work utilized SAT solvers and resolution traces to set up a PCH technology and corresponding tool flows. In this article, we present a novel technology for PCH based on inductive invariants. For sequential circuits, our approach is fundamentally stronger than the previous SAT-based one since we avoid the limitations of bounded unrolling. We contrast our technology to existing ones and show that it fits into previously proposed tool flows. We conduct experiments with four categories of benchmark circuits and report consumer and producer runtime and peak memory consumption, as well as the size of the certificates and the distribution of the workload between producer and consumer. Experiments clearly show that our new induction-based technology is superior for sequential circuits, whereas the previous SAT-based technology is the better choice for combinational circuits. AU - Isenberg, Tobias AU - Platzner, Marco AU - Wehrheim, Heike AU - Wiersema, Tobias ID - 68 IS - 4 JF - ACM Transactions on Design Automation of Electronic Systems TI - Proof-Carrying Hardware via Inductive Invariants ER - TY - THES AU - Jakobs, Marie-Christine ID - 685 TI - On-The-Fly Safety Checking - Customizing Program Certification and Program Restructuring ER - TY - JOUR AB - Today, software is traded worldwide on global markets, with apps being downloaded to smartphones within minutes or seconds. This poses, more than ever, the challenge of ensuring safety of software in the face of (1) unknown or untrusted software providers together with (2) resource-limited software consumers. The concept of Proof-Carrying Code (PCC), years ago suggested by Necula, provides one framework for securing the execution of untrusted code. PCC techniques attach safety proofs, constructed by software producers, to code. Based on the assumption that checking proofs is usually much simpler than constructing proofs, software consumers should thus be able to quickly check the safety of software. However, PCC techniques often suffer from the size of certificates (i.e., the attached proofs), making PCC techniques inefficient in practice.In this article, we introduce a new framework for the safe execution of untrusted code called Programs from Proofs (PfP). The basic assumption underlying the PfP technique is the fact that the structure of programs significantly influences the complexity of checking a specific safety property. Instead of attaching proofs to program code, the PfP technique transforms the program into an efficiently checkable form, thus guaranteeing quick safety checks for software consumers. For this transformation, the technique also uses a producer-side automatic proof of safety. More specifically, safety proving for the software producer proceeds via the construction of an abstract reachability graph (ARG) unfolding the control-flow automaton (CFA) up to the degree necessary for simple checking. To this end, we combine different sorts of software analysis: expensive analyses incrementally determining the degree of unfolding, and cheap analyses responsible for safety checking. Out of the abstract reachability graph we generate the new program. In its CFA structure, it is isomorphic to the graph and hence another, this time consumer-side, cheap analysis can quickly determine its safety.Like PCC, Programs from Proofs is a general framework instantiable with different sorts of (expensive and cheap) analysis. Here, we present the general framework and exemplify it by some concrete examples. We have implemented different instantiations on top of the configurable program analysis tool CPAchecker and report on experiments, in particular on comparisons with PCC techniques. AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ID - 69 IS - 2 JF - ACM Transactions on Programming Languages and Systems TI - Programs from Proofs: A Framework for the Safe Execution of Untrusted Software ER - TY - GEN AU - Pauck, Felix ID - 109 TI - Cooperative static analysis of Android applications ER - TY - GEN AU - Bröcher, Henrik ID - 201 TI - Evaluation von Graphpartitionierungsalgorithmen im Kontext von Konfigurierbarer Softwarezertifizierung ER - TY - CONF AU - Beringer, Steffen AU - Wehrheim, Heike ED - H. ter Beek, Maurice ED - Gnesi, Stefania ED - Knapp, Alexander ID - 3157 T2 - Critical Systems: Formal Methods and Automated Verification - Joint 21st International Workshop on Formal Methods for Industrial Critical Systems and 16th International Workshop on Automated Verification of Critical Systems, FMICS-AVoCS 2016, Pisa, Italy, September 26-28, 2016, Proceedings TI - Verification of AUTOSAR Software Architectures with Timed Automata ER - TY - CONF AU - Travkin, Oleg AU - Wehrheim, Heike ED - Sampaio, Augusto ED - Wang, Farn ID - 3158 T2 - Theoretical Aspects of Computing - {ICTAC} 2016 - 13th International Colloquium, Taipei, Taiwan, ROC, October 24-31, 2016, Proceedings TI - Verification of Concurrent Programs on Weak Memory Models ER - TY - CONF AU - Schellhorn, Gerhard AU - Travkin, Oleg AU - Wehrheim, Heike ED - Huisman, Marieke ID - 3159 T2 - Integrated Formal Methods - 12th International Conference, {IFM} 2016, Reykjavik, Iceland, June 1-5, 2016, Proceedings TI - Towards a Thread-Local Proof Technique for Starvation Freedom ER - TY - CONF AU - Doherty, Simon AU - Dongol, Brijesh AU - Derrick, John AU - Schellhorn, Gerhard AU - Wehrheim, Heike ED - Fatourou, Panagiota ED - Jim{\'{e}}nez, Ernesto ED - Pedone, Fernando ID - 3160 T2 - 20th International Conference on Principles of Distributed Systems, {OPODIS} 2016, December 13-16, 2016, Madrid, Spain TI - Proving Opacity of a Pessimistic {STM} ER - TY - JOUR AU - Isenberg, Tobias AU - Jakobs, Marie{-}Christine AU - Pauck, Felix AU - Wehrheim, Heike ID - 3161 JF - CoRR TI - Deriving approximation tolerance constraints from verification runs ER - TY - JOUR AB - Today, service compositions often need to be assembled or changed on-the-fly, which leaves only little time for quality assurance. Moreover, quality assurance is complicated by service providers only giving information on their services in terms of domain specific concepts with only limited semantic meaning.In this paper, we propose a method for constructing service compositions based on pre-verified templates. Templates, given as workflow descriptions, are typed over a (domain-independent) template ontology defining concepts and predicates. Their meaning is defined by an abstract semantics, leaving the specific meaning of ontology concepts open, however, only up to given ontology rules. Templates are proven correct using a Hoare-style proof calculus, extended by a specific rule for service calls. Construction of service compositions amounts to instantiation of templates with domain-specific services. Correctness of an instantiation can then simply be checked by verifying that the domain ontology (a) adheres to the rules of the template ontology, and (b) fulfills the constraints of the employed template. AU - Walther, Sven AU - Wehrheim, Heike ID - 175 JF - Science of Computer Programming TI - On-The-Fly Construction of Provably Correct Service Compositions - Templates and Proofs ER - TY - CONF AB - Software verification is an established method to ensure software safety. Nevertheless, verification still often fails, either because it consumes too much resources, e.g., time or memory, or the technique is not mature enough to verify the property. Often then discarding the partial verification, the validation process proceeds with techniques like testing.To enable standard testing to profit from previous, partial verification, we use a summary of the verification effort to simplify the program for subsequent testing. Our techniques use this summary to construct a residual program which only contains program paths with unproven assertions. Afterwards, the residual program can be used with standard testing tools.Our first experiments show that testing profits from the partial verification.The test effort is reduced and combined verification and testing is faster than a complete verification. AU - Czech, Mike AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ED - Jens Knoop, Uwe Zdun ID - 186 T2 - Software Engineering 2016 TI - Just test what you cannot verify! ER - TY - CONF AB - In modern software development, paradigms like component-based software engineering (CBSE) and service-oriented architectures (SOA) emphasize the construction of large software systems out of existing components or services. Therein, a service is a self-contained piece of software, which adheres to a specified interface. In a model-based software design, this interface constitutes our sole knowledge of the service at design time, while service implementations are not available. Therefore, correctness checks or detection of potential errors in service compositions has to be carried out without the possibility of executing services. This challenges the usage of standard software error localization techniques for service compositions. In this paper, we review state-of-the-art approaches for error localization of software and discuss their applicability to service compositions. AU - Krämer, Julia AU - Wehrheim, Heike ID - 224 T2 - Proceedings of the 5th European Conference on Service-Oriented and Cloud Computing (ESOCC 2016) TI - A short survey on using software error localization for service compositions ER - TY - CONF AB - Error detection, localization and correction are time-intensive tasks in software development, but crucial to deliver functionally correct products. Thus, automated approaches to these tasks have been intensively studied for standard software systems. For model-based software systems, the situation is different. While error detection is still well-studied, error localization and correction is a less-studied domain. In this paper, we examine error localization and correction for models of service compositions. Based on formal definitions of error and correction in this context, we show that the classical approach of error localization and correction, i.e. first determining a set of suspicious statements and then proposing changes to these statements, is ineffective in our context. In fact, it lessens the chance to succeed in finding a correction at all.In this paper, we introduce correction proposal as a novel approach on error correction in service compositions integrating error localization and correction in one combined step. In addition, we provide an algorithm to compute such correction proposals automatically. AU - Krämer, Julia AU - Wehrheim, Heike ID - 226 T2 - Proceedings of the 1st International Workshop on Formal to Practical Software Verification and Composition (VeryComp 2016) TI - A Formal Approach to Error Localization and Correction in Service Compositions ER - TY - CONF AB - Information flow analysis studies the flow of data between program entities (e.g. variables), where the allowed flow is specified via security policies. Typical information flow analyses compute a conservative (over-)approximation of the flows in a program. Such an analysis may thus signal non-existing violations of the security policy.In this paper, we propose a new technique for inspecting the reported violations (counterexamples) for spuriousity. Similar to counterexample-guided-abstraction-refinement (CEGAR) in software verification, we use the result of this inspection to improve the next round of the analysis. We prove soundness of this scheme. AU - Töws, Manuel AU - Wehrheim, Heike ID - 227 T2 - Proceedings of the 18th International Conference on Formal Engineering Methods (ICFEM 2016) TI - A CEGAR Scheme for Information Flow Analysis ER - TY - CONF AB - We present PAndA2, an extendable, static analysis tool for Android apps which examines permission related security threats like overprivilege, existence of permission redelegation and permission flows. PAndA2 comes along with a textual and graphical visualization of the analysis result and even supports the comparison of analysis results for different android app versions. AU - Jakobs, Marie-Christine AU - Töws, Manuel AU - Pauck, Felix ED - Ishikawa F, Romanovsky A, Troubitsyna E ID - 170 T2 - Workshop on Formal and Model-Driven Techniques for Developing Trustworthy Systems TI - PAndA 2 : Analyzing Permission Use and Interplay in Android Apps (Tool Paper) ER - TY - THES AU - Isenberg, Tobias ID - 1190 TI - Induction-based Verification of Timed Systems ER - TY - GEN AU - Zhang, Guangli ID - 162 TI - Program Slicing: A Way of Separating WHILE Programs into Precise and Approximate Portions ER - TY - GEN AU - Czech, Mike ID - 164 TI - Predicting Rankings of Software Verification Tools Using Kernels for Structured Data ER - TY - GEN AB - . AU - Dewender, Markus ID - 133 TI - Verifikation von Service Kompositionen mit Spin ER - TY - GEN AB - . AU - Heinisch, Philipp ID - 134 TI - Verifikation von Service Kompositionen mit Prolog ER - TY - CONF AB - Before execution, users should formally validate the correctness of software received from untrusted providers. To accelerate this validation, in the proof carrying code (PCC) paradigm the provider delivers the software together with a certificate, a formal proof of the software’s correctness. Thus, the user only checks if the attached certificate shows correctness of the delivered software.Recently, we introduced configurable program certification, a generic, PCC based framework supporting various software analyses and safety properties. Evaluation of our framework revealed that validation suffers from certificate reading. In this paper, we present two orthogonal approaches which improve certificate validation, both reducing the impact of certificate reading. The first approach reduces the certificate size, storing information only if it cannot easily be recomputed. The second approach partitions the certificate into independently checkable parts. The trick is to read parts of the certificate while already checking read parts. Our experiments show that validation highly benefits from our improvements. AU - Jakobs, Marie-Christine ID - 250 T2 - Proceedings of the 13th International Conference on Software Engineering and Formal Methods (SEFM) TI - Speed Up Configurable Certificate Validation by Certificate Reduction and Partitioning ER - TY - CONF AB - Today, software verification is an established analysis method which can provide high guarantees for software safety. However, the resources (time and/or memory) for an exhaustive verification are not always available, and analysis then has to resort to other techniques, like testing. Most often, the already achieved partial verification results arediscarded in this case, and testing has to start from scratch.In this paper, we propose a method for combining verification and testing in which testing only needs to check the residual fraction of an uncompleted verification. To this end, the partial results of a verification run are used to construct a residual program (and residual assertions to be checked on it). The residual program can afterwards be fed into standardtesting tools. The proposed technique is sound modulo the soundness of the testing procedure. Experimental results show that this combinedusage of verification and testing can significantly reduce the effort for the subsequent testing. AU - Czech, Mike AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ED - Egyed, Alexander ED - Schaefer, Ina ID - 283 T2 - Fundamental Approaches to Software Engineering TI - Just test what you cannot verify! ER - TY - CONF AB - We propose an incremental workflow for the verification of parameterized systems modeled as symmetric networks of timed automata. Starting with a small number of timed automata in the network, a safety property is verified using IC3, a state-of-the-art algorithm based on induction.The result of the verification, an inductive strengthening, is reused proposing a candidate inductive strengthening for a larger network.If the candidate is valid, our main theorem states that the safety property holds for all sizes of the network of timed automata. Otherwise the number of automata is increased and the next iteration is started with a new run of IC3.We propose and thoroughly examine optimizations to our workflow, e.g. Feedback mechanisms to speed up the run of IC3. AU - Isenberg, Tobias ID - 285 T2 - Proceedings of the 15th International Conference on Application of Concurrency to System Design (ACSD) TI - Incremental Inductive Verification of Parameterized Timed Systems ER - TY - THES AU - Besova, Galina ID - 246 TI - Systematic Development and Re-Use of Model Tranformations ER - TY - CONF AB - Programs from Proofs" is a generic method which generates new programs out of correctness proofs of given programs. The technique ensures that the new and given program are behaviorally equivalent and that the new program is easily verifiable, thus serving as an alternative to proof-carrying code concepts. So far, this generic method has one instantiation that verifies type-state properties of programs. In this paper, we present a whole range of new instantiations, all based on data ow analyses. More precisely, we show how an imprecise but fast data ow analysis can be enhanced with a predicate analysis as to yield a precise but expensive analysis. Out of the safety proofs of this analysis, we generate new programs, again behaviorally equivalent to the given ones, which are easily verifiable" in the sense that now the data ow analysis alone can yield precise results. An experimental evaluation practically supports our claim of easy verification. AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ID - 262 T2 - Proceedings of the 30th Annual ACM Symposium on Applied Computing TI - Programs from Proofs of Predicated Dataflow Analyses ER - TY - JOUR AB - Model transformation is a key concept in model-driven software engineering. The definition of model transformations is usually based on meta-models describing the abstract syntax of languages. While meta-models are thereby able to abstract from uperfluous details of concrete syntax, they often loose structural information inherent in languages, like information on model elements always occurring together in particular shapes. As a consequence, model transformations cannot naturally re-use language structures, thus leading to unnecessary complexity in their development as well as in quality assurance.In this paper, we propose a new approach to model transformation development which allows to simplify the developed transformations and improve their quality via the exploitation of the languages׳ structures. The approach is based on context-free graph grammars and transformations defined by pairing productions of source and target grammars. We show that such transformations have important properties: they terminate and are sound, complete, and deterministic. AU - Besova, Galina AU - Steenken, Dominik AU - Wehrheim, Heike ID - 290 JF - Computer Languages, Systems & Structures TI - Grammar-based model transformations: Definition, execution, and quality properties ER - TY - JOUR AU - Ziegert, Steffen AU - Wehrheim, Heike ID - 3162 IS - 3-4 JF - Computer Science - R & D TI - Temporal plans for software architecture reconfiguration ER - TY - CONF AU - Meyer, Roland AU - Wehrheim, Heike ED - Meyer, Roland ED - Platzer, Andr{\'{e}} ED - Wehrheim, Heike ID - 3163 T2 - Correct System Design - Symposium in Honor of Ernst-R{\"{u}}diger Olderog on the Occasion of His 60th Birthday, Oldenburg, Germany, September 8-9, 2015. Proceedings TI - From Program Verification to Time and Space: The Scientific Life of Ernst-R{\"{u}}diger Olderog ER - TY - CONF AU - Derrick, John AU - Dongol, Brijesh AU - Schellhorn, Gerhard AU - Travkin, Oleg AU - Wehrheim, Heike ED - Bj{\o}rner, Nikolaj ED - S. de Boer, Frank ID - 3164 T2 - {FM} 2015: Formal Methods - 20th International Symposium, Oslo, Norway, June 24-26, 2015, Proceedings TI - Verifying Opacity of a Transactional Mutex Lock ER - TY - CONF AU - Wehrheim, Heike AU - Travkin, Oleg ED - Piterman, Nir ID - 3165 T2 - Hardware and Software: Verification and Testing - 11th International Haifa Verification Conference, {HVC} 2015, Haifa, Israel, November 17-19, 2015, Proceedings TI - {TSO} to {SC} via Symbolic Execution ER - TY - GEN ED - Meyer, Roland ED - Platzer, Andr{\'{e}} ED - Wehrheim, Heike ID - 3166 SN - 978-3-319-23505-9 TI - Correct System Design - Symposium in Honor of Ernst-R{\"{u}}diger Olderog on the Occasion of His 60th Birthday, Oldenburg, Germany, September 8-9, 2015. Proceedings ER - TY - CONF AB - Today, service compositions often need to be assembled or changed on-the-fly, which leaves only little time for quality assurance. Moreover, quality assurance is complicated by service providers only giving information on their services in terms of domain specific concepts with only limited semantic meaning. In this paper, we propose a method to construct service compositions based on pre-verifiedtemplates. Templates, given as workflow descriptions, are typed over a (domain-independent) template ontology defining concepts and predicates. Templates are proven correct using an abstract semantics, leaving the specific meaning of ontology concepts open, however, only up to given ontology rules. Construction of service compositions amounts to instantiation of templates with domain-specific services.Correctness of an instantiation can then simply be checked by verifying that the domain ontology(a) adheres to the rules of the template ontology, and (b) fulfills the constraints of the employed template. AU - Walther, Sven AU - Wehrheim, Heike ED - Lanese, Ivan ED - Madelaine, Eric ID - 336 T2 - Proceedings of the 11th International Symposium on Formal Aspects of Component Software (FACS) TI - Verified Service Compositions by Template-Based Construction ER - TY - GEN AU - Korth, Philipp ID - 340 TI - Untersuchung transitiver Eigenschaften der Technik "Programs from Proofs" ER - TY - CONF AU - Becker, Matthias AU - Becker, Steffen AU - Besova, Galina AU - Walther, Sven AU - Wehrheim, Heike ID - 344 T2 - Proceedings of the 40th Euromicro Conference on Software Engineering and Advanced Applications (Work in Progress Session) TI - Towards Systematic Configuration for Architecture Validation ER - TY - CONF AB - There are many technologies for the automation of processesthat deal with services; examples are service discovery and composition.Automation of these processes requires that the services are described semantically. However, semantically described services are currently not oronly rarely available, which limits the applicability of discovery and composition approaches. The systematic support for creating new semanticservices usable by automated technologies is an open problem.We tackle this problem with a template based approach: Domain independent templates are instantiated with domain specific services andboolean expressions. The obtained services have semantic descriptionswhose correctness directly follows from the correctness of the template.Besides the theory, we present experimental results for a service repository in which 85% of the services were generated automatically. AU - Mohr, Felix AU - Walther, Sven ID - 353 T2 - Proceedings of the 14th International Conference on Software Reuse (ICSR) TI - Template-based Generation of Semantic Services ER - TY - CONF AB - Proof-carrying code approaches aim at safe execution of untrusted code by having the code producer attach a safety proof to the code which the code consumer only has to validate. Depending on the type of safety property, proofs can however become quite large and their validation - though faster than their construction - still time consuming. In this paper we introduce a new concept for safe execution of untrusted code. It keeps the idea of putting the time consuming part of proving on the side of the code producer, however, attaches no proofs to code anymore but instead uses the proof to transform the program into an equivalent but more efficiently verifiable program. Code consumers thus still do proving themselves, however, on a computationally inexpensive level only. Experimental results show that the proof effort can be reduced by several orders of magnitude, both with respect to time and space. AU - Wonisch, Daniel AU - Schremmer, Alexander AU - Wehrheim, Heike ID - 383 T2 - Proceedings of the Software Engineering Conference (SE) TI - Programs from Proofs -- Approach and Applications ER - TY - JOUR AU - Schneider, Steve AU - Treharne, Helen AU - Wehrheim, Heike ID - 3167 IS - 2 JF - Formal Asp. Comput. TI - The behavioural semantics of Event-B refinement ER - TY - JOUR AU - Tofan, Bogdan AU - Travkin, Oleg AU - Schellhorn, Gerhard AU - Wehrheim, Heike ID - 3168 JF - Sci. Comput. Program. TI - Two approaches for proving linearizability of multiset ER - TY - JOUR AU - Schellhorn, Gerhard AU - Derrick, John AU - Wehrheim, Heike ID - 3169 IS - 4 JF - {ACM} Trans. Comput. Log. TI - A Sound and Complete Proof Technique for Linearizability of Concurrent Data Structures ER - TY - CONF AU - Derrick, John AU - Dongol, Brijesh AU - Schellhorn, Gerhard AU - Tofan, Bogdan AU - Travkin, Oleg AU - Wehrheim, Heike ED - B. Jones, Cliff ED - Pihlajasaari, Pekka ED - Sun, Jun ID - 3170 T2 - {FM} 2014: Formal Methods - 19th International Symposium, Singapore, May 12-16, 2014. Proceedings TI - Quiescent Consistency: Defining and Verifying Relaxed Linearizability ER - TY - CONF AU - Travkin, Oleg AU - Wehrheim, Heike ED - Yahav, Eran ID - 3171 T2 - Hardware and Software: Verification and Testing - 10th International Haifa Verification Conference, {HVC} 2014, Haifa, Israel, November 18-20, 2014. Proceedings TI - Handling {TSO} in Mechanized Linearizability Proofs ER - TY - CONF AU - Isenberg, Tobias AU - Wehrheim, Heike ED - Merz, Stephan ED - Pang, Jun ID - 3172 T2 - Formal Methods and Software Engineering - 16th International Conference on Formal Engineering Methods, {ICFEM} 2014, Luxembourg, Luxembourg, November 3-5, 2014. Proceedings TI - Timed Automata Verification via {IC3} with Zones ER - TY - CONF AU - A. Schneider, Steve AU - Treharne, Helen AU - Wehrheim, Heike AU - M. Williams, David ED - Albert, Elvira ED - Sekerinski, Emil ID - 3173 T2 - Integrated Formal Methods - 11th International Conference, {IFM} 2014, Bertinoro, Italy, September 9-11, 2014, Proceedings TI - Managing {LTL} Properties in Event-B Refinement ER - TY - JOUR AU - Schneider, Steve AU - Treharne, Helen AU - Wehrheim, Heike AU - M. Williams, David ID - 3174 JF - CoRR TI - Managing {LTL} properties in Event-B refinement ER - TY - JOUR AU - Isenberg, Tobias AU - Wehrheim, Heike ID - 3175 JF - CoRR TI - Proof-Carrying Hardware via {IC3} ER - TY - CONF AB - Configurable program analysis (CPA) is a generic concept for the formalization of different software analysis techniques in a single framework. With the tool CPAchecker, this framework allows for an easy configuration and subsequent automatic execution of analysis procedures ranging from data-flow analysis to model checking. The focus of the tool CPAchecker is thus on analysis. In this paper, we study configurability from the point of view of software certification. Certification aims at providing (via a prior analysis) a certificate of correctness for a program which is (a) tamper-proof and (b) more efficient to check for validity than a full analysis. Here, we will show how, given an analysis instance of a CPA, to construct a corresponding sound certification instance, thereby arriving at configurable program certification. We report on experiments with certification based on different analysis techniques, and in particular explain which characteristics of an underlying analysis allow us to design an efficient (in the above (b) sense) certification procedure. AU - Jakobs, Marie-Christine AU - Wehrheim, Heike ID - 450 T2 - Proceedings of the 21st International Symposium on Model Checking of Software (SPIN) TI - Certification for Configurable Program Analysis ER - TY - CONF AB - Verification of hardware and software usually proceeds separately, software analysis relying on the correctness of processors executing instructions. This assumption is valid as long as the software runs on standard CPUs that have been extensively validated and are in wide use. However, for processors exploiting custom instruction set extensions to meet performance and energy constraints the validation might be less extensive, challenging the correctness assumption.In this paper we present an approach for integrating software analyses with hardware verification, specifically targeting custom instruction set extensions. We propose three different techniques for deriving the properties to be proven for the hardware implementation of a custom instruction in order to support software analyses. The techniques are designed to explore the trade-off between generality and efficiency and span from proving functional equivalence over checking the rules of a particular analysis domain to verifying actual pre and post conditions resulting from program analysis. We demonstrate and compare the three techniques on example programs with custom instructions, using stateof-the-art software and hardware verification techniques. AU - Jakobs, Marie-Christine AU - Platzner, Marco AU - Wiersema, Tobias AU - Wehrheim, Heike ED - Albert, Elvira ED - Sekerinski, Emil ID - 408 T2 - Proceedings of the 11th International Conference on Integrated Formal Methods (iFM) TI - Integrating Software and Hardware Verification ER - TY - CONF AB - Model transformation is a key concept in modeldrivensoftware engineering. The definition of model transformationsis usually based on meta-models describing the abstractsyntax of languages. While meta-models are thereby able to abstractfrom superfluous details of concrete syntax, they often loosestructural information inherent in languages, like information onmodel elements always occurring together in particular shapes.As a consequence, model transformations cannot naturally re-uselanguage structures, thus leading to unnecessary complexity intheir development as well as analysis.In this paper, we propose a new approach to model transformationdevelopment which allows to simplify and improve thequality of the developed transformations via the exploitation ofthe languages’ structures. The approach is based on context-freegrammars and transformations defined by pairing productions ofsource and target grammars. We show that such transformationsexhibit three important characteristics: they are sound, completeand deterministic. AU - Besova, Galina AU - Steenke, Dominik AU - Wehrheim, Heike ID - 417 T2 - Proceedings 3rd Workshop on Model Driven Approaches in System Development (MDASD) TI - Grammar-based model transformations ER - TY - GEN AU - Pauck, Felix ID - 418 TI - Generierung von Eigenschaftsprüfern in einem Hardware/Software-Co-Verifikationsverfahren ER - TY - CONF AU - Isenberg, Tobias AU - Steenken, Dominik AU - Wehrheim, Heike ED - Beyer, Dirk ED - Boreale, Michele ID - 3176 T2 - Formal Techniques for Distributed Systems - Joint {IFIP} {WG} 6.1 International Conference, {FMOODS/FORTE} 2013, Held as Part of the 8th International Federated Conference on Distributed Computing Techniques, DisCoTec 2013, Florence, Italy, June 3-5, 2013. Proceedings TI - Bounded Model Checking of Graph Transformation Systems via {SMT} Solving ER - TY - CONF AU - Travkin, Oleg AU - Mütze, Annika AU - Wehrheim, Heike ED - Bertacco, Valeria ED - Legay, Axel ID - 3177 T2 - Hardware and Software: Verification and Testing - 9th International Haifa Verification Conference, {HVC} 2013, Haifa, Israel, November 5-7, 2013, Proceedings TI - {SPIN} as a Linearizability Checker under Weak Memory Models ER - TY - CONF AU - Dongol, Brijesh AU - Travkin, Oleg AU - Derrick, John AU - Wehrheim, Heike ED - Liu, Zhiming ED - Woodcock, Jim ED - Zhu, Huibiao ID - 3178 T2 - Theoretical Aspects of Computing - {ICTAC} 2013 - 10th International Colloquium, Shanghai, China, September 4-6, 2013. Proceedings TI - A High-Level Semantics for Program Execution under Total Store Order Memory ER - TY - CONF AU - Ziegert, Steffen AU - Wehrheim, Heike ED - Kowalewski, Stefan ED - Rumpe, Bernhard ID - 3179 T2 - Software Engineering 2013: Fachtagung des GI-Fachbereichs Softwaretechnik, 26. Februar - 2. M{\"{a}}rz 2013 in Aachen TI - Temporal Reconfiguration Plans for Self-Adaptive Systems ER - TY - CONF AB - Runtime monitoring aims at ensuring program safety by monitoring the program's behaviour during execution and taking appropriate action before a program violates some property.Runtime monitoring is in particular important when an exhaustive formal verification fails. While the approach allows for a safe execution of programs, it may impose a significant runtime overhead.In this paper, we propose a novel technique combining verification and monitoring which incurs no overhead during runtime at all. The technique proceeds by using the inconclusive result of a verification run as the basis for transforming the program into one where all potential points of failure are replaced by HALT statements. The new program is safe by construction, behaviourally equivalent to the original program (except for unsafe behaviour),and has the same performance characteristics. AU - Wonisch, Daniel AU - Schremmer, Alexander AU - Wehrheim, Heike ID - 469 T2 - Proceedings of the 11th International Conference on Software Engineering and Formal Methods (SEFM) TI - Zero Overhead Runtime Monitoring ER - TY - THES AB - Software systems are playing an increasing role in our everyday life, and as the amount of software applications grows, so does their complexity and the relevance of their computations. Software components can be found in many systems that are charged with safety-critical tasks, such as control systems for aviation or power plants. Hence, software verification techniques that are capable of proving the absence of critical errors are becoming more and more important in the field software engineering. A well-established approach to software verification is model checking. Applying this technique involves an exhaustive exploration of a state space model corresponding to the system under consideration. The major challenge in model checking is the so-called state explosion problem: The state space of a software system grows exponentially with its size. Thus, the straightforward modelling of real-life systems practically impossible. A common approach to this problem is the application of abstraction techniques, which reduce the original state space by mapping it on a significantly smaller abstract one. Abstraction inherently involves a loss of information, and thus, the resulting abstract model may be too imprecise for a definite result in verification. Therefore, abstraction is typically combined with abstraction refinement: An initially very coarse abstract model is iteratively refined, i.e. enriched with new details about the original system, until a level of abstraction is reached that is precise enough for a definite outcome. Abstraction refinement-based model checking is fully automatable and it is considered as one of the most promising approaches to the state explosion problem in verification. However, it is still faced with a number of challenges. There exist several types of abstraction techniques and not every type is equally well-suited for all kinds of systems and verification tasks. Moreover, the selection of adequate refinement steps is nontrivial and typically the most crucial part of the overall approach: Unfavourable refinement decisions can compromise the state space-reducing effect of abstraction, and as a consequence, can easily lead to the failure of verification. It is, however, hard to predict which refinement steps will eventually be expedient for verification – and which not. AU - Timm, Nils ID - 478 TI - Three-Valued Abstraction and Heuristic-Guided Refinement for Verifying Concurrent Systems ER - TY - CONF AB - Proof-carrying code approaches aim at safe execution of untrusted code by having the code producer attach a safety proof to the code which the code consumer only has to validate. Depending on the type of safety property, proofs can however become quite large and their validation - though faster than their construction - still time consuming. In this paper we introduce a new concept for safe execution of untrusted code. It keeps the idea of putting the time consuming part of proving on the side of the code producer, however, attaches no proofs to code anymore but instead uses the proof to transform the program into an equivalent but more efficiently verifiable program. Code consumers thus still do proving themselves, however, on a computationally inexpensive level only. Experimental results show that the proof effort can be reduced by several orders of magnitude, both with respect to time and space. AU - Wonisch, Daniel AU - Schremmer, Alexander AU - Wehrheim, Heike ID - 498 T2 - Proceedings of the 25th International Conference on Computer Aided Verification (CAV) TI - Programs from Proofs – A PCC Alternative ER - TY - CONF AB - In the Semantic (Web) Services area, services are considered black boxes with a semantic description of their interfaces as to allow for precise service selection and configuration. The semantic description is usually grounded on domain-specific concepts as modeled in ontologies. This accounts for types used in service signatures, but also predicates occurring in preconditions and effects of services. Ontologies, in particular those enhanced with rules, capture the knowledge of domain experts on properties of and relations between domain concepts. In this paper, we present a verification technique for service compositions which makes use of this domain knowledge. We consider a service composition to be an assembly of services of which we just know signatures, preconditions, and effects. We aim at proving that a composition satisfies a (user-defined) requirement, specified in terms of guaranteed preconditions and required postconditions. As an underlying verification engine we use an SMT solver. To take advantage of the domain knowledge (and often, to enable verification at all), the knowledge is fed into the solver in the form of sorts, uninterpreted functions and in particular assertions as to enhance the solver’s reasoning capabilities. Thereby, we allow for deductions within a domain previously unknown to the solver. We exemplify our technique on a case study from the area of water network optimization software. AU - Walther, Sven AU - Wehrheim, Heike ID - 517 T2 - Proceedings of the 18th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS) TI - Knowledge-Based Verification of Service Compositions - An SMT approach ER - TY - JOUR AU - Travkin, Oleg AU - Wehrheim, Heike AU - Schellhorn, Gerhard ID - 3180 JF - {ECEASST} TI - Proving Linearizability of Multiset with Local Proof Obligations ER - TY - JOUR AU - Ruhroth, Thomas AU - Wehrheim, Heike ID - 3181 IS - 3 JF - Sci. Comput. Program. TI - Model evolution and refinement ER - TY - CONF AU - Schellhorn, Gerhard AU - Wehrheim, Heike AU - Derrick, John ED - Madhusudan, P. ED - A. Seshia, Sanjit ID - 3182 T2 - Computer Aided Verification - 24th International Conference, {CAV} 2012, Berkeley, CA, USA, July 7-13, 2012 Proceedings TI - How to Prove Algorithms Linearisable ER - TY - CONF AB - Predicate abstraction is an established technique for reducing the size of the state space during verification. In this paper, we extend predication abstraction with block-abstraction memoization (BAM), which exploits the fact that blocks are often executed several times in a program. The verification can thus benefit from caching the values of previous block analyses and reusing them upon next entry into a block. In addition to function bodies, BAM also performs well for nested loops. To further increase effectiveness, block memoization has been integrated with lazy abstraction adopting a lazy strategy for cache refinement. Together, this achieves significant performance increases: our tool (an implementation within the configurable program analysis framework CPAchecker) has won the Competition on Software Verification 2012 in the category “Overall”. AU - Wonisch, Daniel AU - Wehrheim, Heike ID - 590 T2 - Proceedings of the 14th International Conference on Formal Engineering Methods (ICFEM) TI - Predicate Analysis with Block-Abstraction Memoization ER - TY - CONF AB - Predicate abstraction is an established technique in software verification. It inherently includes an abstraction refinement loop successively adding predicates until the right level of abstraction is found. For concurrent systems, predicate abstraction can be combined with spotlight abstraction, further reducing the state space by abstracting away certain processes. Refinement then has to decide whether to add a new predicate or a new process. Selecting the right predicates and processes is a crucial task: The positive effect of abstraction may be compromised by unfavourable refinement decisions. Here we present a heuristic approach to abstraction refinement. The basis for a decision is a set of refinement candidates, derived by multiple counterexample-generation. Candidates are evaluated with respect to their influence on other components in the system. Experimental results show that our technique can significantly speed up verification as compared to a naive abstraction refinement. AU - Timm, Nils AU - Wehrheim, Heike AU - Czech, Mike ID - 608 T2 - Proceedings of the 14th International Conference on Formal Engineering Methods (ICFEM) TI - Heuristic-Guided Abstraction Refinement for Concurrent Systems ER - TY - CONF AB - Block Abstraction Memoization (ABM) is a technique in software model checking that exploits the modularity of programs during verification by caching. To this end, ABM records the results of block analyses and reuses them if possible when revisiting the same block again. In this paper we present an implementation of ABM into the predicate-analysis component of the software-verification framework CPAchecker. With our participation at the Competition on Software Verification we aim at providing evidence that ABM can not only substantially increase the efficiency of predicate analysis but also enables verification of a wider range of programs. AU - Wonisch, Daniel ID - 627 T2 - Proceedings of the 18th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS) TI - Block Abstraction Memoization for CPAchecker ER - TY - CONF AB - In model-driven development of multi-layer systems (e.g. application, platform and infrastructure), each layer is usually described by separate models. When generating analysis models or code, these separate models rst of all need to be linked. Hence, existing model transformations for single layers cannot be simply re-used. In this paper, we present a modular approach to the transformation of multi-layer systems. It employs model weaving to dene the interconnections between models of dierent layers. The weaving models themselves are subject to model transformations: The result of transforming a weaving model constitutes a conguration for the models obtained by transforming single layers, thereby allowing for a re-use of existing model transformations. We exemplify our approach by the generation of analysis models for component-based software. AU - Besova, Galina AU - Walther, Sven AU - Wehrheim, Heike AU - Becker, Steffen ID - 565 T2 - Proceedings of the 15th International Conference on Model Driven Engineering Languages & Systems (MoDELS) TI - Weaving-based configuration and modular transformation of multi-layer systems ER - TY - JOUR AU - Schneider, Steve AU - Treharne, Helen AU - Wehrheim, Heike ID - 3183 JF - Electr. Notes Theor. Comput. Sci. TI - Bounded Retransmission in Event-B{\(\parallel\)}CSP: a Case Study ER - TY - JOUR AU - Derrick, John AU - Schellhorn, Gerhard AU - Wehrheim, Heike ID - 3184 IS - 1 JF - {ACM} Trans. Program. Lang. Syst. TI - Mechanically verified proof obligations for linearizability ER - TY - CONF AU - Ruhroth, Thomas AU - Wehrheim, Heike AU - Ziegert, Steffen ID - 3185 T2 - 37th {EUROMICRO} Conference on Software Engineering and Advanced Applications, {SEAA} 2011, Oulu, Finland, August 30 - September 2, 2011 TI - ReL: {A} Generic Refactoring Language for Specification and Execution ER - TY - CONF AU - Derrick, John AU - Schellhorn, Gerhard AU - Wehrheim, Heike ED - J. Butler, Michael ED - Schulte, Wolfram ID - 3186 T2 - {FM} 2011: Formal Methods - 17th International Symposium on Formal Methods, Limerick, Ireland, June 20-24, 2011. Proceedings TI - Verifying Linearisability with Potential Linearisation Points ER - TY - CONF AU - Steenken, Dominik AU - Wehrheim, Heike AU - Wonisch, Daniel ED - da Silva Sim{\~{a}}o, Adenilso ED - Morgan, Carroll ID - 3187 T2 - Formal Methods, Foundations and Applications - 14th Brazilian Symposium, {SBMF} 2011, S{\~{a}}o Paulo, Brazil, September 26-30, 2011, Revised Selected Papers TI - Sound and Complete Abstract Graph Transformation ER - TY - CONF AU - Schneider, Steve AU - Treharne, Helen AU - Wehrheim, Heike ED - Derrick, John ED - A. Boiten, Eerke ED - Reeves, Steve ID - 3188 T2 - Proceedings 15th International Refinement Workshop, Refine@FM 2011, Limerick, Ireland, 20th June 2011. TI - A {CSP} Account of Event-B Refinement ER - TY - JOUR AU - Leuschel, Michael AU - Wehrheim, Heike ID - 647 IS - 10 JF - Science of Computer Programming TI - Selected papers on Integrated Formal Methods (iFM09) ER - TY - JOUR AB - Today, the concept of service oriented architectures provides a way of building integrated solutions out of existing services. To this end, services from different providers are composed using advanced orchestration and choreography techniques. However, while this principle allows for greater flexibility at a smaller cost, the use of third party services also includes a risk: Deployed services might not work as claimed by their providers. In this paper, we propose a technique for analyzing the expected reliability of service compositions based on ratings given by (previous) service users. Every service thereby comes with a reputation, and the analysis computes an overall reliability of a service composition from the reputations of its constituent services. The proposed model-driven approach proceeds by translating statechart models of service compositions into input for a probabilistic model checker (PRISM) using state-of-the-art model transformations techniques. The approach has been implemented as an Eclipse plug-in and is fully compliant with UML. AU - Besova, Galina AU - Wehrheim, Heike AU - Wagner, Annika ID - 649 IS - 2 JF - Electronic Notes in Theoretical Computer Science TI - Reputation-based Reliability Prediction of Service Compositions ER - TY - GEN AU - Schremmer, Alexander ID - 658 TI - Function Specification Inference Using Craig Interpolation ER - TY - CONF AU - Schneider, Steve AU - Treharne, Helen AU - Wehrheim, Heike ED - M{\'{e}}ry, Dominique ED - Merz, Stephan ID - 3195 T2 - Integrated Formal Methods - 8th International Conference, {IFM} 2010, Nancy, France, October 11-14, 2010. Proceedings TI - A {CSP} Approach to Control in Event-B ER - TY - CONF AU - Dräger, Klaus AU - Kupriyanov, Andrey AU - Finkbeiner, Bernd AU - Wehrheim, Heike ED - Esparza, Javier ED - Majumdar, Rupak ID - 3196 T2 - Tools and Algorithms for the Construction and Analysis of Systems, 16th International Conference, {TACAS} 2010, Held as Part of the Joint European Conferences on Theory and Practice of Software, {ETAPS} 2010, Paphos, Cyprus, March 20-28, 2010. Proceedings TI - {SLAB:} {A} Certifying Model Checker for Infinite-State Concurrent Systems ER - TY - JOUR AU - Steenken, Dominik AU - Wehrheim, Heike AU - Wonisch, Daniel ID - 3198 JF - CoRR TI - Towards {A} Shape Analysis for Graph Transformation Systems ER - TY - JOUR AU - Derrick, John AU - Wehrheim, Heike ID - 3189 IS - 3 JF - Sci. Comput. Program. TI - Model transformations across views ER - TY - CONF AU - Schäfer, Wilhelm AU - Wehrheim, Heike ED - Engels, Gregor ED - Lewerentz, Claus ED - Sch{\"{a}}fer, Wilhelm ED - Sch{\"{u}}rr, Andy ED - Westfechtel, Bernhard ID - 3191 T2 - Graph Transformations and Model-Driven Engineering - Essays Dedicated to Manfred Nagl on the Occasion of his 65th Birthday TI - Model-Driven Development with Mechatronic {UML} ER - TY - CONF AU - Timm, Nils AU - Wehrheim, Heike ED - Song Dong, Jin ED - Zhu, Huibiao ID - 3193 T2 - Formal Methods and Software Engineering - 12th International Conference on Formal Engineering Methods, {ICFEM} 2010, Shanghai, China, November 17-19, 2010. Proceedings TI - On Symmetries and Spotlights - Verifying Parameterised Systems ER - TY - CONF AU - Hülsbusch, Mathias AU - König, Barbara AU - Rensink, Arend AU - Semenyak, Maria AU - Soltenborn, Christian AU - Wehrheim, Heike ED - M{\'{e}}ry, Dominique ED - Merz, Stephan ID - 3194 T2 - Integrated Formal Methods - 8th International Conference, {IFM} 2010, Nancy, France, October 11-14, 2010. Proceedings TI - Showing Full Semantics Preservation in Model Transformation - {A} Comparison of Techniques ER - TY - JOUR AU - Wehrheim, Heike AU - Wonisch, Daniel ID - 3199 IS - 2 JF - Electr. Notes Theor. Comput. Sci. TI - Compositional {CSP} Traces Refinement Checking ER - TY - JOUR AU - Ruhroth, Thomas AU - Wehrheim, Heike ID - 3200 JF - Electr. Notes Theor. Comput. Sci. TI - Static Class Elements for Object-Z ER - TY - CONF AU - Ruhroth, Thomas AU - Voigt, Hendrik AU - Wehrheim, Heike ID - 3201 T2 - 35th Euromicro Conference on Software Engineering and Advanced Applications, {SEAA} 2009, Patras, Greece, August 27-29, 2009, Proceedings TI - Measure, Diagnose, Refactor: {A} Formal Quality Cycle for Software Models ER - TY - GEN ED - Leuschel, Michael ED - Wehrheim, Heike ID - 3202 SN - 978-3-642-00254-0 TI - Integrated Formal Methods, 7th International Conference, {IFM} 2009, D{\"{u}}sseldorf, Germany, February 16-19, 2009. Proceedings ER - TY - JOUR AU - Wehrheim, Heike ID - 3203 JF - Electr. Notes Theor. Comput. Sci. TI - Refinement in the Presence of Unknowns ER - TY - JOUR AU - Estler, H.{-}Christian AU - Wehrheim, Heike ID - 3204 JF - Electr. Notes Theor. Comput. Sci. TI - Alloy as a Refactoring Checker? ER - TY - JOUR AU - Möller, Michael AU - Olderog, Ernst-Rüdiger AU - Rasch, Holger AU - Wehrheim, Heike ID - 3205 IS - 2 JF - Formal Asp. Comput. TI - Integrating a formal method into a software engineering process with {UML} and Java ER - TY - JOUR AU - Brückner, Ingo AU - Dräger, Klaus AU - Finkbeiner, Bernd AU - Wehrheim, Heike ID - 3206 IS - 4 JF - Fundam. Inform. TI - Slicing Abstractions ER - TY - CONF AU - Engels, Gregor AU - Kleppe, Anneke AU - Rensink, Arend AU - Semenyak, Maria AU - Soltenborn, Christian AU - Wehrheim, Heike ED - Schieferdecker, Ina ED - Hartman, Alan ID - 3207 T2 - Model Driven Architecture - Foundations and Applications, 4th European Conference, {ECMDA-FA} 2008, Berlin, Germany, June 9-13, 2008. Proceedings TI - From {UML} Activities to {TAAL} - Towards Behaviour-Preserving Model Transformations ER - TY - CONF AU - Derrick, John AU - Schellhorn, Gerhard AU - Wehrheim, Heike ED - Barthe, Gilles ED - S. de Boer, Frank ID - 3208 T2 - Formal Methods for Open Object-Based Distributed Systems, 10th {IFIP} {WG} 6.1 International Conference, {FMOODS} 2008, Oslo, Norway, June 4-6, 2008, Proceedings TI - Mechanizing a Correctness Proof for a Lock-Free Concurrent Stack ER - TY - CONF AU - Metzler, Björn AU - Wehrheim, Heike AU - Wonisch, Daniel ED - Liu, Shaoying ED - S. E. Maibaum, T. ED - Araki, Keijiro ID - 3209 T2 - Formal Methods and Software Engineering, 10th International Conference on Formal Engineering Methods, {ICFEM} 2008, Kitakyushu-City, Japan, October 27-31, 2008. Proceedings TI - Decomposition for Compositional Verification ER - TY - CONF AU - Wehrheim, Heike ED - S. Fitzgerald, John ED - Elisabeth Haxthausen, Anne ED - Yenig{\"{u}}n, H{\"{u}}sn{\"{u}} ID - 3210 T2 - Theoretical Aspects of Computing - {ICTAC} 2008, 5th International Colloquium, Istanbul, Turkey, September 1-3, 2008. Proceedings TI - Bounded Model Checking for Partial Kripke Structures ER - TY - JOUR AU - Derrick, John AU - Wehrheim, Heike ID - 3211 IS - 1 JF - Acta Inf. TI - On using data abstractions for model checking refinements ER - TY - JOUR AU - Metzler, Björn AU - Wehrheim, Heike ID - 3212 IS - 2 JF - Electr. Notes Theor. Comput. Sci. TI - Extending a Component Specification Language with Time ER - TY - JOUR AU - Estler, H.{-}Christian AU - Ruhroth, Thomas AU - Wehrheim, Heike ID - 3213 JF - Electr. Notes Theor. Comput. Sci. TI - Modelchecking Correctness of Refactorings - Some Experiments ER - TY - CONF AU - Engels, Gregor AU - Güldali, Baris AU - Soltenborn, Christian AU - Wehrheim, Heike ED - Sch{\"{u}}rr, Andy ED - Nagl, Manfred ED - Z{\"{u}}ndorf, Albert ID - 3214 T2 - Applications of Graph Transformations with Industrial Relevance, Third International Symposium, {AGTIVE} 2007, Kassel, Germany, October 10-12, 2007, Revised Selected and Invited Papers TI - Assuring Consistency of Business Process Models and Web Services Using Visual Contracts ER -