CNRS Informatics Laboratory of Grenoble

Grenoble, France

CNRS Informatics Laboratory of Grenoble

Grenoble, France
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Braibant T.,CNRS Informatics Laboratory of Grenoble | Pous D.,CNRS Informatics Laboratory of Grenoble
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

We present a set of tools for rewriting modulo associativity and commutativity (AC) in Coq, solving a long-standing practical problem. We use two building blocks: first, an extensible reflexive decision procedure for equality modulo AC; second, an OCaml plug-in for pattern matching modulo AC. We handle associative only operations, neutral elements, uninterpreted function symbols, and user-defined equivalence relations. By relying on type-classes for the reification phase, we can infer these properties automatically, so that end-users do not need to specify which operation is A or AC, or which constant is a neutral element. © 2011 Springer-Verlag.


Braibant T.,CNRS Informatics Laboratory of Grenoble
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

We propose a new library to model and verify hardware circuits in the Coq proof assistant. This library allows one to easily build circuits by following the usual pen-and-paper diagrams. We define a deep-embedding: we use a (dependently typed) data-type that models the architecture of circuits, and a meaning function. We propose tactics that ease the reasoning about the behavior of the circuits, and we demonstrate that our approach is practicable by proving the correctness of various circuits: a text-book divide and conquer adder of parametric size, some higher-order combinators of circuits, and some sequential circuits: a buffer, and a register. © 2011 Springer-Verlag.


Chahuara P.,CNRS Informatics Laboratory of Grenoble | Portet F.,CNRS Informatics Laboratory of Grenoble | Vacher M.,CNRS Informatics Laboratory of Grenoble
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

This research addresses the issue of building home automation systems reactive to voice for improved comfort and autonomy at home. The focus of this paper is on the context-aware decision process which uses a dedicated Markov Logic Network approach to benefit from the formal logical representation of domain knowledge as well as the ability to handle uncertain facts inferred from real sensor data. The approach has been experiemented in a real smart home with naive and users with special needs. © 2013 Springer International Publishing Switzerland.


Braibant T.,CNRS Informatics Laboratory of Grenoble | Pous D.,CNRS Informatics Laboratory of Grenoble
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

We present a reflexive tactic for deciding the equational theory of Kleene algebras in the Coq proof assistant. This tactic relies on a careful implementation of efficient finite automata algorithms, so that it solves casual equations almost instantaneously. The corresponding decision procedure was proved correct and complete; correctness is established w.r.t. any model (including binary relations), by formalising Kozen's initiality theorem. © 2010 Springer-Verlag.


Portet F.,CNRS Informatics Laboratory of Grenoble | Vacher M.,CNRS Informatics Laboratory of Grenoble | Golanski C.,MULTICOM | Roux C.,MULTICOM | Meillon B.,CNRS Informatics Laboratory of Grenoble
Personal and Ubiquitous Computing | Year: 2013

Smart homes equipped with ambient intelligence technology constitute a promising direction to enable the growing number of elderly to continue to live in their own home as long as possible. However, this calls for technological solutions that suit their specific needs and capabilities. The Sweet-Home project aims at developing a new user friendly technology for home automation based on voice command. This paper reports a user evaluation assessing the acceptance and fear of this new technology. Eight healthy persons between 71 and 88 years old, 7 relatives (child, grandchild or friend) and 3 professional carers participated in a user evaluation. During about 45 min, the persons were questioned in co-discovery in the Domus smart home alternating between interview and wizard of Oz periods followed by a debriefing. The experience aimed at testing four important aspects of the project: voice command, communication with the outside world, domotics system interrupting a person's activity, and electronic agenda. Voice interface appeared to have a great potential to ease daily living for elderly and frail persons and would be better accepted than more intrusive solutions. By considering still healthy and independent elderly people in the user evaluation, an interesting finding that came up is their overall acceptance provided the system does not drive them to a lazy lifestyle by taking control of everything. This particular fear must be addressed for the development of smart homes that support daily living by giving them more ability to control rather than putting them away from the daily routine. © 2011 Springer-Verlag London Limited.


Braibant T.,CNRS Informatics Laboratory of Grenoble | Pous D.,CNRS Informatics Laboratory of Grenoble
Logical Methods in Computer Science | Year: 2012

We present a re exive tactic for deciding the equational theory of Kleene algebras in the Coq proof assistant. This tactic relies on a careful implementation of efficient finite automata algorithms, so that it solves casual equations instantaneously and properly scales to larger expressions. The decision procedure is proved correct and complete: correctness is established w.r.t. any model by formalising Kozen's initiality theorem; a counter-example is returned when the given equation does not hold. The correctness proof is challenging: it involves both a precise analysis of the underlying automata algorithms and a lot of algebraic reasoning. In particular, we have to formalise the theory of matrices over a Kleene algebra. We build on the recent addition of first-class typeclasses in Coq in order to work efficiently with the involved algebraic structures. © Thomas Braibant and Damien Pous.


Peltier N.,CNRS Informatics Laboratory of Grenoble
Journal of Logic and Computation | Year: 2014

We study the complexity of the satisfiability problem for a class of logical formulae called iterated propositional schemata, modelling infinite sequences of structurally similar propositional formulae (such as the sequence (Equation), where n ∈ ℕ). We prove that the problem is EXPSPACE-complete in general and PSPACE-complete if the numbers occurring in the formula are polynomially bounded by the size of the schema. We then consider more restricted classes: we prove that the problem is still PSPACE-complete for the Horn class, but only NP-complete for the Krom class (sets of clauses of length 2). Finally, we devise a simple criterion ensuring that the satisfiability problem is in P. © The Author, 2012.


Safadi B.,CNRS Informatics Laboratory of Grenoble | Quenot G.,CNRS Informatics Laboratory of Grenoble
Proceedings - International Workshop on Content-Based Multimedia Indexing | Year: 2013

In this paper, we propose and evaluate a method for optimizing descriptors used for content-based multimedia indexing and retrieval. A large variety of descriptors are commonly used for this purpose. However, the most efficient ones often have characteristics preventing them to be easily used in large scale systems. They may have very high dimensionality (up to tens of thousands dimensions) and/or be suited for a distance costly to compute (e.g. X 2). The proposed method combines a PCA-based dimensionality reduction with pre- and post-PCA non-linear transformations. The resulting transformation is globally optimized. The produced descriptors have a much lower dimensionality while performing at least as well, and often significantly better, with the Euclidean distance than the original high dimensionality descriptors with their optimal distance. The method has been validated and evaluated for a variety of descriptors using TRECVid 2010 semantic indexing task data. It has then be applied at large scale for the TRECVid 2012 semantic indexing task on tens of descriptors of various types and with initial dimensionalities from 15 up to 32,768. The same transformation can be used also for multimedia retrieval in the context of query by example and/or relevance feedback. © 2013 IEEE.


Delahaye M.,CNRS Informatics Laboratory of Grenoble | Kosmatov N.,CEA Saclay Nuclear Research Center | Signoles J.,CEA Saclay Nuclear Research Center
Proceedings of the ACM Symposium on Applied Computing | Year: 2013

Various combinations of static and dynamic analysis techniques were recently shown to be beneficial for software verification. A frequent obstacle to combining different tools in a completely automatic way is the lack of a common specification language. Our work proposes to translate a Pre-Post based specification into executable C code. This paper presents E-ACSL, subset of the ACSL specification language for C programs, and its automatic translator into C implemented as a FRAMA-C plug-in. The resulting C code is executable and can be used by a dynamic analysis tool. We illustrate how the PATHCRAWLER test generation tool automatically treats such pre- and postconditions specified as C functions. Copyright 2013 ACM.


Pous D.,CNRS Informatics Laboratory of Grenoble
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

We prove "untyping" theorems: in some typed theories (semirings, Kleene algebras, residuated lattices, involutive residuated lattices), typed equations can be derived from the underlying untyped equations. As a consequence, the corresponding untyped decision procedures can be extended for free to the typed settings. Some of these theorems are obtained via a detour through fragments of cyclic linear logic, and give rise to a substantial optimisation of standard proof search algorithms. © 2010 Springer-Verlag Berlin Heidelberg.

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