IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-10-13T17:46:26ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2011-11-22T13:39:08Z2011-12-20T12:00:25Zhttp://eprints.imtlucca.it/id/eprint/1018This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/10182011-11-22T13:39:08ZAction planning for graph transition systemsGraphs are suitable modeling formalisms for software and hardware systems involving aspects such as communication,
object orientation, concurrency, mobility and distribution. State spaces of such systems can be represented by graph transition systems, which are basically transition systems whose states and transitions represent graphs and graph morphisms. In this paper, we propose the modeling of graph transition systems in PDDL and the application of heuristic search planning for their analysis. We consider different heuristics and present experimental results.Stefan EdelkampShahid JabbarAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-11-22T12:19:23Z2011-12-20T12:00:25Zhttp://eprints.imtlucca.it/id/eprint/1016This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/10162011-11-22T12:19:23ZProtocol verification with heuristic searchWe present an approach to reconcile explicit state model checking and heuristic directed search and provide experimental evidence that the model checking problem for concurrent systems, such as communications protocols, can be solved more efficiently, since finding a state violating a property can be understood as a directed search problem. In our work we combine the expressive power and implementation efficiency of the SPIN model checker with the HSF heuristic search workbench, yielding the HSF-SPIN tool that we have implemented. We start off from the A* algorithm and some of its derivatives and define heuristics for various system properties that guide the search so that it finds error states faster. In this paper we focus on safety properties and provide heuristics for invariant and assertion violation and deadlock detection. We provide experimental results for applying HSF-SPIN to two toy protocols and one real world protocol, the CORBA GIOP protocol.Stefan EdelkampAlberto Lluch-Lafuentealberto.lluch@imtlucca.itStefan Leue2011-11-22T11:25:48Z2011-12-20T12:00:25Zhttp://eprints.imtlucca.it/id/eprint/1013This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/10132011-11-22T11:25:48ZAbstraction in directed model checkingAbstraction is one of the most important issues to cope with large and infinite state spaces in model checking and to reduce the verification efforts. The abstract system is smaller than the original one and if the abstract system satisfies a correctness specification, so does the concrete one. However, abstractions may introduce a behavior violating the specification that is not present in the original system.
This paper bypasses this problem by proposing the combination of abstraction with heuristic search to improve error detection. The abstract system is explored in order to create a database that stores the exact distances from abstract states to the set of abstract error states. To check, whether or not the abstract behavior is present in the original system, effcient exploration algorithms exploit the database as a guidance.Stefan EdelkampAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-05-18T08:54:26Z2014-10-07T14:41:43Zhttp://eprints.imtlucca.it/id/eprint/171This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1712011-05-18T08:54:26ZTrail-directed model checkingHSF-SPIN is a Promela model checker based on heuristic search strategies. It utilizes heuristic estimates in order to direct the search for finding software bugs in concurrent systems. As a consequence, HSF-SPIN is able to find shorter trails than blind depth-first search.
This paper contributes an extension to the paradigm of directed model checking to shorten already established unacceptable long error trails. This approach has been implemented in HSF-SPIN. For selected benchmark and industrial communication protocols experimental evidence is given that trail-directed model-checking effectively shortcuts existing witness paths.
Stefan EdelkampAlberto Lluch-Lafuentealberto.lluch@imtlucca.itStefan Leue2011-05-17T14:37:17Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/170This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1702011-05-17T14:37:17ZDirected Explicit Model Checking with HSF-SPINWe present the explicit state model checker HSF-SPIN which is based on the model checker SPIN and its Promela modeling language. HSF-SPIN incorporates directed search algorithms for checking safety and a large class of LTL-specified liveness properties. We start off from the A* algorithm and define heuristics to accelerate the search into the direction of a specified failure situation. Next we propose an improved nested depth-first search algorithm that exploits the structure of Promela Never-Claims. As a result of both improvements, counterexamples will be shorter and the explored part of the state space will be smaller than with classical approaches, allowing to analyze larger state spaces. We evaluate the impact of the new heuristics and algorithms on a set of protocol models, some of which are real-world industrial protocols.
Stefan EdelkampAlberto Lluch-Lafuentealberto.lluch@imtlucca.itStefan Leue2011-05-17T13:54:29Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/167This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1672011-05-17T13:54:29ZDirected explicit-state model checking in the validation of communication protocolsThe success of model checking is largely based on its ability to efficiently locate errors in software designs. If an error is found, a model checker produces a trail that shows how the error state can be reached, which greatly facilitates debugging. However, while current model checkers find error states efficiently, the counterexamples are often unnecessarily lengthy, which hampers error explanation. This is due to the use of naive search algorithms in the state space exploration. In this paper we present approaches to the use of heuristic search algorithms in explicit-state model checking. We present the class of A * directed search algorithms and propose heuristics together with bitstate compression techniques for the search of safety property violations. We achieve great reductions in the length of the error trails, and in some instances render problems analyzable by exploring a much smaller number of states than standard depth-first search. We then suggest an improvement of the nested depth-first search algorithm and show how it can be used together with A * to improve the search for liveness property violations. Our approach to directed explicit-state model checking has been implemented in a tool set called HSF-SPIN. We provide experimental results from the protocol validation domain using HSF-SPIN.Stefan EdelkampStefan LeueAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-05-13T13:07:05Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/169This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1692011-05-13T13:07:05ZPartial Order Reduction in Directed Model CheckingPartial order reduction is a very succesful technique for avoiding the state explosion problem that is inherent to explicit state model checking of asynchronous concurrent systems. It exploits the commutativity of concurrently executed transitions in interleaved system runs in order to reduce the size of the explored state space. Directed model checking on the other hand addresses the state explosion problem by using guided search techniques during state space exploration. As a consequence, shorter errors trails are found and less search effort is required than when using standard depth-first or breadth-first search. We analyze how to combine directed model checking with partial order reduction methods and give experimental results on how the combination of both techniques performs.
Alberto Lluch-Lafuentealberto.lluch@imtlucca.itStefan EdelkampStefan Leue2011-05-13T12:54:53Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/168This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1682011-05-13T12:54:53ZPartial-order reduction and trail improvement in directed model checkingIn this paper we present work on trail improvement and partial-order reduction in the context of directed explicit-state model checking. Directed explicit-state model checking employs directed heuristic search algorithms such as A* or best-first search to improve the error-detection capabilities of explicit-state model checking. We first present the use of directed explicit-state model checking to improve the length of already established error trails. Second, we show that partial-order reduction, which aims at reducing the size of the state space by exploiting the commutativity of concurrent transitions in asynchronous systems, can coexist well with directed explicit-state model checking. Finally, we illustrate how to mitigate the excessive length of error trails produced by partial-order reduction in explicit-state model checking. In this context we also propose a combination of heuristic search and partial-order reduction to improve the length to already provided counterexamples. Stefan EdelkampStefan LeueAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-03-31T14:52:50Z2011-07-11T14:34:34Zhttp://eprints.imtlucca.it/id/eprint/157This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1572011-03-31T14:52:50ZHeuristic Search for the Analysis of Graph Transition SystemsGraphs are suitable modeling formalisms for software and hardware systems involving aspects such as communication, object orientation, concurrency, mobility and distribution. State spaces of such systems can be represented by graph transition systems, which are basically transition systems whose states and transitions represent graphs and graph morphisms. Heuristic search is a successful Artificial Intelligence technique for solving exploration problems implicitly present in games, planning, and formal verification. Heuristic search exploits information about the problem being solved to guide the exploration process. The main benefits are significant reductions in the search effort and the size of solutions. We propose the application of heuristic search for the analysis of graph transition systems. We define algorithms and heuristics and present experimental results.Stefan EdelkampShahid JabbarAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-03-24T10:18:31Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/163This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1632011-03-24T10:18:31ZCost-Algebraic Heuristic SearchHeuristic search is used to efficiently solve the single-node
shortest path problem in weighted graphs. In practice, however,
one is not only interested in finding a short path, but
an optimal path, according to a certain cost notion. We propose
an algebraic formalism that captures many cost notions,
like typical Quality of Service attributes. We thus generalize
A*, the popular heuristic search algorithm, for solving
optimal-path problem. The paper provides an answer to a
fundamental question for AI search, namely to which general
notion of cost, heuristic search algorithms can be applied. We
proof correctness of the algorithms and provide experimental
results that validate the feasibility of the approach.Stefan EdelkampShahid JabbarAlberto Lluch-Lafuentealberto.lluch@imtlucca.it