| 1. |
- Khamespanah, Ehsan, et al.
(author)
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State Distribution Policy for Distributed Model Checking of Actor Models
- 2015
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In: Electronic Communications of the EASST. - Berlin : Universitätsverlag der TU Berlin. - 1863-2122. ; 72, s. 1-15
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Journal article (peer-reviewed)abstract
- Model checking temporal properties is often reduced to finding accepting cycles in Büchi automata. A key ingredient for an effective distributed model checking technique is a distribution policy that does not split the potential accepting cycles of the corresponding automaton among several nodes. In this paper, we introduce a distribution policy to reduce the number of split cycles. This policy is based on the call dependency graph, obtained from the message passing skeleton of the model. We prove theoretical results about the correspondence between the cycles of call dependency graph and the cycles of the concrete state space and provide empirical data obtained from applying our distribution policy in state space generation and reachability analysis. We take Rebeca, an imperative interpretation of actors, as our modeling language and implement the introduced policy in its distributed state space generator. Our technique can be applied to other message-driven actor-based models where concurrent objects or services are units of concurrency.
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| 2. |
- Aceto, L., et al.
(author)
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Decompositional Reasoning about the History of Parallel Processes
- 2011
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In: Fundamentals of software engineering. - Heidelberg : Springer Berlin/Heidelberg. - 1611-3349 .- 0302-9743. - 9783642293191 - 9783642293207 ; , s. 32-47
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Conference paper (peer-reviewed)abstract
- This paper presents a decomposition technique for Hennessy-Milner logic with past and its extension with recursively defined formulae. In order to highlight the main ideas and technical tools, processes are described using a subset of CCS with parallel composition, nondeterministic choice, action prefixing and the inaction constant. The study focuses on developing decompositional reasoning techniques for parallel contexts in that language. © 2012 Springer-Verlag.
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| 3. |
- Aceto, Luca, et al.
(author)
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Rule formats for determinism and idempotence
- 2012
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In: Science of Computer Programming. - Amsterdam : Elsevier BV. - 0167-6423 .- 1872-7964. ; 77:7-8, s. 889-907
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Journal article (peer-reviewed)abstract
- Determinism is a semantic property of (a fragment of) a language that specifies that a program cannot evolve operationally in several different ways. Idempotence is a property of binary composition operators requiring that the composition of two identical specifications or programs will result in a piece of specification or program that is equivalent to the original components. In this paper, we propose (related) meta-theorems for guaranteeing the determinism and idempotence of binary operators. These meta-theorems are formulated in terms of syntactic templates for operational semantics, called rule formats. In order to obtain a powerful rule format for idempotence, we make use of the determinism of certain transition relations in the definition of the format for idempotence. We show the applicability of our formats by applying them to various operational semantics from the literature.
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| 4. |
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| 5. |
- Jaghoori, Mohammad Mahdi, et al.
(author)
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Symmetry and partial order reduction techniques in model checking Rebeca
- 2010
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In: Acta Informatica. - New York : Springer. - 0001-5903 .- 1432-0525. ; 47:1, s. 33-66
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Journal article (peer-reviewed)abstract
- Rebeca is an actor-based language with formal semantics which is suitable for modeling concurrent and distributed systems and protocols. Due to its object model, partial order and symmetry detection and reduction techniques can be efficiently applied to dynamic Rebecamodels. We present two approaches for detecting symmetry in Rebeca models: One that detects symmetry in the topology of inter-connections among objects and another one which exploits specific data structures to reflect internal symmetry in the internal structure of an object. The former approach is novel in that it does not require any input from the modeler and can deal with the dynamic changes of topology. This approach is potentially applicable to a wide range of modeling languages for distributed and reactive systems. We have also developed a model checking tool that implements all of the above-mentioned techniques. The evaluation results show significant improvements in model size and model-checkingtime.
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| 6. |
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| 7. |
- Khakpour, Narges, et al.
(author)
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Formal modeling of evolving self-adaptive systems
- 2012
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In: Science of Computer Programming. - Amsterdam : Elsevier. - 0167-6423 .- 1872-7964. ; 78:1, s. 3-26
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Journal article (peer-reviewed)abstract
- In this paper, we present a formal model, named PobSAM (Policy-based Self-Adaptive Model), for developing and modeling self-adaptive evolving systems. In this model, policies are used as a mechanism to direct and adapt the behavior of self-adaptive systems. A PobSAM model is a collection of autonomous managers and managed actors. The managed actors are dedicated to the functional behavior while the autonomous managers govern the behavior of managed actors by enforcing suitable policies. A manager has a set of configurations including two types of policies: governing policies and adaptation policies. To adapt the system behavior in response to the changes, the managers switch among different configurations. We employ the combination of an algebraic formalism and an actor-based model to specify this model formally. Managed actors are expressed by an actor model. Managers are modeled as meta-actors whose configurations are described using a multi-sorted algebra called CA. We provide an operational semantics for PobSAM using labeled transition systems. Furthermore, we provide behavioral equivalence of different sorts of CA in terms of splitting bisimulation and prioritized splitting bisimulation. Equivalent managers send the same set of messages to the actors. Using our behavioral equivalence theory, we can prove that the overall behavior of the system is preserved by substituting a manager by an equivalent one.
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| 8. |
- Khakpour, Narges, et al.
(author)
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PobSAM : policy-based managing of actors in self-adaptive systems
- 2010
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In: Proceedings of the 6th International Workshop on Formal Aspects of Component Software (FACS’09, Eindhoven, The Netherlands, November 2-3, 2009). - Amsterdam : Elsevier. ; 263, s. 129-143
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Conference paper (peer-reviewed)
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| 9. |
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| 10. |
- Aceto, Luca, et al.
(author)
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A Rule Format for Unit Elements
- 2009
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Reports (other academic/artistic)abstract
- This paper offers a meta-theorem for languages with a Structural Operational Semantics (SOS) in the style of Plotkin. Namely, it proposes a generic rule format for SOS guaranteeing that certain constants act as left- or right-unit elements for a set of binary operators. We show the generality of our format by applying it to a wide range of operators from the literature on process calculi.
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