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564 discussions

Mercredi 16 décembre 2020: Stefan Schwoon, ENS Paris-Saclay

by Nicolas BOUTRY

Chers collègues, La prochaine session du séminaire Performance et Généricité du LRDE (Laboratoire de Recherche et Développement de l'EPITA) aura lieu le Mercredi 16 décembre 2020 (11h -- 12h) en distanciel (en raison des conditions sanitaires actuelles) au lien suivant: https://eu.bbcollab.com/collab/ui/session/guest/95a72a9dc7b0405c8c281ea3157… <https://eu.bbcollab.com/collab/ui/session/guest/95a72a9dc7b0405c8c281ea3157…> Vous trouverez sur le site du séminaire [1] les prochaines séances, les résumés, captations vidéos et planches des exposés précédents [2], et le détail de cette séance [3]. [1] http://seminaire.lrde.epita.fr [2] http://seminaire.lrde.epita.fr/Archives [3] http://seminaire.lrde.epita.fr/2020-12-16 Au programme du Mercredi 16 décembre 2020 : * 11h -- 12h: Diagnosis and Opacity in Partially Observable Systems -- Stefan Schwoon, ENS Paris-Saclay http://www.lsv.fr/~schwoon/ In a partially observable system, diagnosis is the task of detecting certain events, for instance fault occurrences. In the presence of hostile observers, on the other hand, one is interested in rendering a system opaque, i.e. making it impossible to detect certain "secret" events. The talk will present some decidability and complexity results for these two problems when the system is represented as a finite automaton or a Petri net. We then also consider the problem of active diagnosis, where the observer has some control over the system. In this context, we study problems such as the computational complexity of the synthesis problem, the memory required for the controller, and the delay between a fault occurrence and its detection by the diagnoser. The talk is based on joint work with B. Bérard, S. Haar, S. Haddad, T. Melliti, and S. Schmitz. -- Stefan Schwoon studied Computer Science at the University of Hildesheim and received a PhD from the Technical University of Munich in 2002. He held the position of Scientific Assistent at the University of Stuttgart from 2002 to 2007, and at the Technical University in Munich from 2007 to 2009. He is currently Associate Professor (Maître de conférences) at Laboratoire Spécification et Vérification (LSV), ENS Paris-Saclay, and a member of the INRIA team Mexico. His research interests include model checking and diagnosis on concurrent and partially-observable systems. L'entrée du séminaire est libre. Merci de bien vouloir diffuser cette information le plus largement possible. N'hésitez pas à nous faire parvenir vos suggestions d'orateurs.

4 years, 3 months

Habilitation defense

by Didier Verna

Dear all, I am pleased to announce my habilitation defense, entitled (dynamic (programming paradigms)) ;; performance and expressivity to be held on Friday, July 10, 14:00 CEST. Due to the current pandemic, the defense will take place on a Zoom public channel. The actual link to the video-conference will be provided later on, at the following URL: https://www.lrde.epita.fr/~didier/research/publications/papers.php#verna.20… The jury is composed as follows. Reporters: Robert Strandh, University of Bordeaux, France Nicolas Neuß, FAU, Erlangen-Nürnberg, Germany Manuel Serrano, INRIA, Sophia Antipolis, France Examiners: Marco Antoniotti, University of Milan, Italy Ralf Möller, Université of Lübech, Germany Gérard Assayag, IRCAM, Paris, France -- Resistance is futile. You will be jazzimilated. Lisp, Jazz, Aïkido: http://www.didierverna.info

4 years, 9 months

New publication: Practical “paritizing” of Emerson-Lei automata

by Florian Renkin

I am happy to announce that the following paper has been accepted at the 18th International Symposium on Automated Technology for Verification and Analysis (ATVA'20) Practical "paritizing" of Emerson-Lei automata Florian Renkin, Alexandre Duret-Lutz, Adrien Pommellet https://www.lrde.epita.fr/wiki/Publications/renkin.20.atva [1] Abstract: We introduce a new algorithm that takes a Transition-based Emerson-Lei Automaton (TELA), that is, an ω-automaton whose acceptance condition is an arbitrary Boolean formula on sets of transitions to be seen infinitely or finitely often, and converts it into a Transition-based Parity Automaton (TPA). To reduce the size of the output TPA, the algorithm combines and optimizes two procedures based on a latest appearance record principle, and introduces a partial degeneralization. Our motivation is to use this algorithm to improve our LTL synthesis tool, where producing deterministic parity automata is an intermediate step. -- Florian Renkin Links: ------ [1] https://www.lrde.epita.fr/wiki/Publications/blahoudek.20.atva

4 years, 9 months

Soutenance Julie Rivet 17 juillet 14h

by jrivet

**English below** Bonjour à toutes et à tous, J'ai le plaisir de vous inviter à la soutenance de ma thèse qui s'intitule "Non-iterative methods for image improvement in digital holography of the retina" (ci-joint un court résumé). Elle aura lieu le 17 juillet à 14h, dans l'amphithéâtre 401 à l'EPITA, 14-16 Rue Voltaire, 94270 Le Kremlin-Bicêtre (pour plus d'informations : https://www.lrde.epita.fr/wiki/Affiche-these-JR), dans le respect des distances de sécurité. Elle sera également diffusée par visioconférence. Le lien pour y accéder vous sera communiqué prochainement. La soutenance sera suivie d'un pot à côté de l'amphithéâtre. A bientôt je l'espère, Julie Rivet -- Hello everyone, I am pleased to invite you to the defense of my thesis entitled "Non-iterative methods for image improvement in digital holography of the retina" (a short abstract is attached). It will take place on July 17th at 2pm, in the amphitheatre 401 at EPITA, 14-16 Rue Voltaire, 94270 Le Kremlin-Bicêtre (for more information: https://www.lrde.epita.fr/wiki/Affiche-these-JR), with respect to safety distances. It will also be broadcast by videoconference. The link to access it will be communicated to you shortly. The defense will be followed by a toast next to the amphitheatre. See you soon I hope, Julie Rivet

4 years, 9 months

New publication: Improving swarming using genetic algorithms

by Renault Etienne

Greetings, We are please to announce that the following paper has been accepted for publication in "Innovations in Systems and Software Engineering: a NASA journal (ISSE)". Title and corresponding authors: "Improving swarming using genetic algorithms" Etienne Renault (1) (1) LRDE, EPITA, Le Kremlin-Bicêtre, France Abstract: The verification of temporal properties against a given system may require the exploration of its full state space. In explicit model checking, this exploration uses a depth-first search and can be achieved with multiple randomized threads to increase performance. Nonetheless, the topology of the state space and the exploration order can cap the speedup up to a certain number of threads. This paper proposes a new technique that aims to tackle this limitation by generating artificial initial states, using genetic algorithms. Threads are then launched from these states and thus explore different parts of the state space. Our prototype implementation is 10% faster than state-of-the-art algorithms on a general benchmark and 40% on a specialized benchmark. Even if we expected a decrease in an order of magnitude, these results are still encouraging since they suggest a new way to handle existing limitations. Empirically, our technique seems well suited for "linear topology", i.e., the one we can obtain when combining model checking algorithms with partial-order reduction techniques. More information at : https://www.lrde.epita.fr/wiki/Publications/renault.20.isse <https://www.lrde.epita.fr/wiki/Publications/renault.20.isse>

4 years, 10 months

[Last CfP] Onward! Essays @SPLASH 2020, Chicago, Nov 15-20

by Didier Verna

Onward! Essays 2020 ACM SIGPLAN International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software Renaissance Chicago Downtown Hotel Chicago, USA November 15--20 2020 Part of SPLASH 2020 Systems, Programming Languages and Applications: Software for Humanity https://2020.splashcon.org/track/splash-2020-Onward-essays Onward! is a premier multidisciplinary conference focused on everything to do with programming and software: including processes, methods, languages, communities, applications and education. Compared to other conferences, Onward! is more radical, more visionary, and more open to ideas that are well-argued but not yet proven. It is not looking for research-as-usual papers. To allow room for bigger, bolder and/or less mature ideas, it accepts less exact methods of validation, such as compelling arguments, exploratory implementations, and substantial examples. Onward! Essays is looking for clear and compelling pieces of writing about topics important to the software community (there is also a parallel Papers track with a seperate announcement). An essay can be an exploration of the topic and its impact, or a story about the circumstances of its creation; it can present a personal view of what is, explore a terrain, or lead the reader in an act of discovery; it can be a philosophical digression or a deep analysis. It can describe a personal journey, perhaps the one the author took to reach an understanding of the topic. The subject area—software, programming, and programming languages—should be interpreted broadly and can include the relationship of software to human endeavors, or its philosophical, sociological, psychological, historical, or anthropological underpinnings. Format and Selection: Onward! essays must describe unpublished work that is not currently submitted for publication elsewhere as described by SIGPLAN's Republication Policy. Submitters should also be aware of ACM's Policy and Procedures on Plagiarism. Onward! essays should use the ACM SIGPLAN Conference acmart format. Please refer to the conference's website above for full details. The Onward! Essays track follows a two-phase review process. Essays are peer-reviewed in a single-blind manner. Accepted essays will appear in the Onward! Proceedings in the ACM Digital Library, and must be presented at the conference. Submissions will be judged on the potential impact of the ideas and the quality of the presentation. Important dates: All deadlines are midnight, anywhere on Earth. Essay submission: 23 May First-round notification: 11 July Second-round submission: 15 August Final notification: 30 August Conference: 15--20 November Programme Committee: Didier Verna, EPITA Research lab, France (Program Chair) Anya Helene Bagge, University of Bergen, Norway Alexandre Bergel, University of Chile Jean Bresson, Ableton, Germany Maxime Chevalier-Boisvert, Université de Montréal, Québec Elisa Gonzalez Boix, Vrije Universiteit Brussel, Belgium Hidehiko Masuhara, Tokyo Institute of Technology, Japan Kent Pitman, PTC, USA Donya Quick, Stevens Institute of Technology, USA Gordana Rakić, University of Novi Sad, Serbia -- Resistance is futile. You will be jazzimilated. Lisp, Jazz, Aïkido: http://www.didierverna.info

4 years, 10 months

New publication: LTL Model Checking for Communicating Concurrent Programs

by adrien

I am happy to announce that the following paper has been accepted in the Innovations in Systems and Software Engineering (ISSE) journal. LTL Model Checking for Communicating Concurrent Programs Adrien Pommellet and Tayssir Touili Abstract: We present in this paper a new approach to the static analysis of concurrent programs with procedures. To this end, we model multi-threaded programs featuring recursive procedure calls and synchronisation by rendez-vous between parallel threads with communicating pushdown systems (from now on CPDSs). The reachability problem for this particular class of automata is unfortunately undecidable. However, it has been shown that an efficient abstraction of the execution traces language can nonetheless be computed. To this end, an algebraic framework to over-approximate context-free languages has been introduced by Bouajjani et al. In this paper, we combine this framework with an automata-theoretic approach in order to approximate an answer to the model checking problem of the linear-time temporal logic (from now on LTL) on CPDSs. We then present an algorithm that, given a single-indexed or stutter-invariant LTL formula, allows us to prove that no run of a CPDS verifies this formula if the procedure ends.

4 years, 10 months

New publication: Seminator 2 Can Complement Generalized Büchi Automata via Improved Semi-Determinization

by Alexandre Duret-Lutz

I am happy to announce that the following paper has been accepted at the 32nd International Conference on Computer-Aided Verification (CAV'20), to be held virtually in July 2020. Seminator 2 Can Complement Generalized Büchi Automata via Improved Semi-Determinization František Blahoudek¹, Alexandre Duret-Lutz², Jan Strejček³ ¹University of Texas at Austin, USA ²LRDE, EPITA, Le Kremlin-Bicêtre, France ³Faculty of Informatics, Masaryk University, Brno, Czech Republic https://www.lrde.epita.fr/wiki/Publications/blahoudek.20.atva Abstract: We present the second generation of the tool Seminator that transforms transition-based generalized Büchi automata (TGBAs) into equivalent semi-deterministic automata. The tool has been extended with numerous optimizations and produces considerably smaller automata than its first version. In connection with the state-of-the-art LTL to TGBAs translator Spot, Seminator 2 produces smaller (on average) semi-deterministic automata than the direct LTL to semi-deterministic automata translator ltl2ldgba of the Owl library. Further, Seminator 2 has been extended with an improved NCSB complementation procedure for semi-deterministic automata, providing a new way to complement automata that is competitive with state-of-the-art complementation tools. -- Alexandre Duret-Lutz

4 years, 10 months

Spot 2.9 released

by Alexandre Duret-Lutz

We are happy to announce the release of Spot 2.9 Spot is a library of algorithms for manipulating LTL formulas and omega-automata. This is a major release that has been under development for 9 months. It contains new features contributed by from Florian Renkin and myself. A summary of those changes is given at the end of this email. Note that version 2.9 and the following 2.9.x minor releases are likely to be the last releases using C++14. We plan is to switch to C++17 for the next major release. The current code-base is already compatible with C++17, so tools using Spot as a library may consider switching to C++17 already. You can find the new release here: http://www.lrde.epita.fr/dload/spot/spot-2.9.tar.gz See https://spot.lrde.epita.fr/ for documentation and installation instructions. Please direct any feedback to <spot(a)lrde.epita.fr>. New in spot 2.9 (2020-04-30) Command-line tools: - When the --check=stutter-sensitive-example option is passed to tools like ltl2tgba, autfilt, genaut, or ltldo, the produced automata are checked for stutter-invariance (as in the --check=stutter-invariant case), additionally a proof of stutter-sensitiveness is provided as two stutter-equivalent words: one accepted, and one rejected. These sample words are printed in the HOA output. % ltl2tgba --check=stutter-sensitive-example Xa | grep word: spot-accepted-word: "!a; cycle{a}" spot-rejected-word: "!a; !a; cycle{a}" - autfilt learned the --partial-degeneralize option, to remove conjunctions of Inf, or disjunctions of Fin that appears in arbitrary conditions. - ltlfilt and autfilt learned a --nth=RANGE (a.k.a. -N) option to select a range of their input formulas or automata (assuming a 1-based numbering). - When running translators, ltlcross will now display {names} when supplied. - ltlcross is now using the generic emptiness check procedure introduced in Spot 2.7, as opposed to removing Fin acceptance before using a classical emptiness check. - ltlcross learned a --save-inclusion-products=FILENAME option. Its use cases are probably quite limited. We use that to generate benchmarks for our generic emptiness check procedure. - ltlsynt --algo=lar uses the new version of to_parity() mentionned below. The old version is available via --algo=lar.old - ltlsynt learned --csv=FILENAME, to record some statistics about the duration of its different phases. - The dot printer is now automatically using rectangles with rounded corners for automata states if one state label have five or more characters. This saves space with very long labels. Use --dot=c, --dot=e, or --dot=E to force the use of Circles, Ellipses, or rEctangles. Library: - Historically, Spot only supports LTL with infinite semantics so it had automatic simplifications reducing X(1) and X(0) to 1 and 0 whenever such formulas are constructed. This caused issues for users of LTLf formulas, where it is important to distinguish a "weak next" (for which X(1)=1 but X(0)!=0) from a "strong next" (for which X(0)=0 but X(1)!=1). To accommodate this, this version introduces a new operator op::strong_X in addition to the existing op::X (whose interpretation is now weak in LTLf). The syntax for the strong next is X[!] as a reference to the PSL syntax (where the strong next is written X!). Trivial simplification rules for X are changed to just X(1) = 1 (and not X(0)=0 anymore) while we have X[!]0 = 0 The X(0)=0 and X[!]1=1 reductions are now preformed during LTL simplification, not automatically. Aside from the from_ltlf() function, the other functions of the library handle X and X[!] in the same way, since there is no difference between X and X[!] over infinite words. Operators F[n:m!] and G[n:m!] are also supported as strong variants of F[n:m] and G[n:m], but those four are only implemented as syntactic sugar. - acc_cond::acc_code::parity(bool, bool, int) was not very readable, as it was unclear to the reader what the boolean argument meant. The following sister functions can now improve readability: parity_max(is_odd, n) = parity(true, is_odd, n) parity_max_odd(n) = parity_max(true, n) parity_max_even(n) = parity_max(false, n) parity_min(is_odd, n) = parity(false, is_odd, n) parity_min_odd(n) = parity_min(true, n) parity_min_even(n) = parity_min(false, n) - partial_degeneralize() is a new function performing partial degeneralization to get rid of conjunctions of Inf terms, or disjunctions of Fin terms in acceptance conditions. - simplify_acceptance_here() and simplify_acceptance() learned to simplify subformulas like Fin(i)&Fin(j) or Inf(i)|Inf(j), or some more complex variants of those. If i is uniquely used in the acceptance condition, these become respectively Fin(i) or Inf(i), and the automaton is adjusted so that i also appears where j appeared. - acc_code::unit_propagation() is a new method for performing unit propagation in acceptance condition. E.g. Fin(0) | (Inf(0) & Inf(1)) becomes Fin(0) | Inf(1). This is now called by simplify_acceptance_here(). - propagate_marks_vector() and propagate_marks_here() are helper functions for propagating marks on the automaton: ignoring self-loops and out-of-SCC transitions, marks common to all the input transitions of a state can be pushed to all its outgoing transitions, and vice-versa. This is repeated until a fix point is reached. propagate_marks_vector() does not modify the automaton and returns a vector of the acc_cond::mark_t that should be on each transition; propagate_marks_here() actually modifies the automaton. - rabin_to_buchi_if_realizable() is a new variant of rabin_to_buchi_maybe() that converts a Rabin-like automaton into a Büchi automaton only if the resulting Büchi automaton can keep the same transition structure (where the ..._maybe() variant would modify the Rabin automaton if needed). - to_parity() has been rewritten. It now combines several strategies for paritizing automata with any acceptance condition. - relabel_bse(), used by ltlfilt --relabel-bool, is now better at dealing with n-ary operators and isolating subsets of operands that can be relabeled as a single term. - print_dot()'s default was changed to use circles for automata with fewer than 10 unamed states, ellipses for automata with up to 1000 unamed states (or named states with up to 4 characters), and rounded rectangles otherwise. Rectangles are also used for automata with acceptance bullets on states. The new "E" option can be used to force rectangles in all situations. - The generic emptiness check has been slightly improved (doing fewer recursive calls in the worst case). Backward-incompatible changes: - iar() and iar_maybe() have been moved from spot/twaalgos/rabin2parity.hh spot/twaalgos/toparity.hh and marked as deprecated, they should be replaced by to_parity(). In case the input is Rabin-like or Streett-like, to_parity() should be at least as good as iar(). - The twa_graph::is_alternating() and digraph::is_alternating() methods, deprecated in Spot 2.3.1 (2017-02-20), have been removed. Bugs fixed: - Relabeling automata could introduce false edges. Those are now removed. - Emptiness checks, and scc_info should now ignore edges labeled with false. - relabel_bse() could incorrectly relabel Boolean subformulas that had some atomic propositions in common. -- Alexandre Duret-Lutz

4 years, 11 months

[CfP] Reminder: Onward! Essays / SPLASH 2020, Nov. 15-20, Chicago.

by Didier Verna

Onward! Essays 2020 ACM SIGPLAN International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software Renaissance Chicago Downtown Hotel Chicago, USA November 15--20 2020 Part of SPLASH 2020 Systems, Programming Languages and Applications: Software for Humanity https://2020.splashcon.org/track/splash-2020-Onward-essays Onward! is a premier multidisciplinary conference focused on everything to do with programming and software: including processes, methods, languages, communities, applications and education. Compared to other conferences, Onward! is more radical, more visionary, and more open to ideas that are well-argued but not yet proven. It is not looking for research-as-usual papers. To allow room for bigger, bolder and/or less mature ideas, it accepts less exact methods of validation, such as compelling arguments, exploratory implementations, and substantial examples. Onward! Essays is looking for clear and compelling pieces of writing about topics important to the software community (there is also a parallel Papers track with a seperate announcement). An essay can be an exploration of the topic and its impact, or a story about the circumstances of its creation; it can present a personal view of what is, explore a terrain, or lead the reader in an act of discovery; it can be a philosophical digression or a deep analysis. It can describe a personal journey, perhaps the one the author took to reach an understanding of the topic. The subject area—software, programming, and programming languages—should be interpreted broadly and can include the relationship of software to human endeavors, or its philosophical, sociological, psychological, historical, or anthropological underpinnings. Format and Selection: Onward! essays must describe unpublished work that is not currently submitted for publication elsewhere as described by SIGPLAN's Republication Policy. Submitters should also be aware of ACM's Policy and Procedures on Plagiarism. Onward! essays should use the ACM SIGPLAN Conference acmart format. Please refer to the conference's website above for full details. The Onward! Essays track follows a two-phase review process. Essays are peer-reviewed in a single-blind manner. Accepted essays will appear in the Onward! Proceedings in the ACM Digital Library, and must be presented at the conference. Submissions will be judged on the potential impact of the ideas and the quality of the presentation. Important dates: All deadlines are midnight, anywhere on Earth. Essay submission: 23 Mai (#COVID19 extended by one month!) First-round notification: 11 June Second-round submission: 15 July Final notification: 30 July Conference: 18--20 November Programme Committee: Didier Verna, EPITA Research lab, France (Program Chair) Anya Helene Bagge, University of Bergen, Norway Alexandre Bergel, University of Chile Jean Bresson, Ableton, Germany Maxime Chevalier-Boisvert, Université de Montréal, Québec Elisa Gonzalez Boix, Vrije Universiteit Brussel, Belgium Hidehiko Masuhara, Tokyo Institute of Technology, Japan Kent Pitman, PTC, USA Donya Quick, Stevens Institute of Technology, USA Gordana Rakić, University of Novi Sad, Serbia -- Resistance is futile. You will be jazzimilated. Jazz site: http://www.didierverna.com Other sites: http://www.didierverna.info

4 years, 11 months

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Annonce