An unexpected application of minimization theory to module decompositions

The aim of this work is to show how we can decompose a module (if decomposable) into an indecomposable module with the help of the minimization process.Comment: 15-02-200

Algebraic Elimination of epsilon-transitions

We present here algebraic formulas associating a k-automaton to a k-epsilon-automaton. The existence depends on the definition of the star of matrices and of elements in the semiring k. For this reason, we present the theorem which allows the transformation of k-epsilon-automata into k-automata. The two automata have the same behaviour.Comment: 13 decembre 200

Moderate Growth Time Series for Dynamic Combinatorics Modelisation

Here, we present a family of time series with a simple growth constraint. This family can be the basis of a model to apply to emerging computation in business and micro-economy where global functions can be expressed from local rules. We explicit a double statistics on these series which allows to establish a one-to-one correspondence between three other ballot-like strunctures

A Graph Transformation-Based Approach for the Validation of Checkpointing Algorithms in Distributed Systems

International audience—Autonomic Computing Systems are oriented to pre-vente the human intervention and to enable distributed systems to manage themselves. One of their challenges is the efficient monitoring at runtime oriented to collect information from which the system can automatically repair itself in case of failure. Quasi-Synchronous Checkpointing is a well-known technique, which allows processes to recover in spite of failures. Based on this technique, several checkpointing algorithms have been developed. According to the checkpoint properties detected and ensured, they are classified into: Strictly Z-Path Free (SZPF), Z-Path Free (ZPF) and Z-Cycle Free (ZCF). In the literature, the simulation has been the method adopted for the performance evaluation of checkpointing algorithms. However, few works have been designed to validate their correctness. In this paper, we propose a validation approach based on graph transformation oriented to automatically detect the previous mentioned checkpointing properties. To achieve this, we take the vector clocks resulting from the algorithm execution, and we model it into a causal graph. Then, we design and use transformation rules oriented to verify if in such a causal graph, the algorithm is exempt from non desirable patterns, such as Z-paths or Z-cycles, according to the case

Vérification des propriétés non-fonctionnelles pour l'orchestration de services web

La composition de services est une tâche primordiale dans le développement de systèmes orientés service. L'orchestration se présente comme un ensemble de mécanismes pour la composition d'un nouveau service web formé d'un ensemble de services atteignables. Afin de valider une telle composition, deux classes de propriétés non fonctionnelles doivent être prises en considération à savoir les propriétés génériques et les propriétés spécifiques. Les propriétés génériques peuvent être vérifiées pour tous les services web invoqués dans une orchestration. Les propriétés spécifiques constituent les relations d'interdépendance entre les différentes activités au sein d'un processus d'orchestration. Ces propriétés ne peuvent pas être vérifiées directement sur le processus, l'utilisation donc d'une technique formelle s'avère intéressante. Pour se faire, nous présenterons dans cet article notre approche formelle pour la validation d'une orchestration de services web. L'approche adopte BPEL 2.0 (Business Process Execution Language) comme langage d'orchestration de services web et utilise le model-checker SPIN pour la vérification. La spécification BPEL est traduite en code Promela, le langage de spécification de SPIN, afin de vérifier aussi bien les propriétés génériques que les propriétés spécifiques exprimées en LTL (Linear Temporal Logic). L'outil de transformation de BPEL en Promela est développé en utilisant ANTLR (ANother Tool for Language Recognition). Ce travail a été couronné par le développement de l'outil {\sc BpelVT} (BPEL Verification Tool) afin de consolider l'approche proposée

Position paper: An integration approach of service composition models: from choreography to orchestration

This paper introduces an approach addressing the transition from choreography to orchestration. As far as validation method is achieved through the use of model-checker. We are interested in various levels of transformations. Initially, the process of transformation is based on a set of heterogeneous business protocols. This unit will consequently provide a choreography as result, which unifies them. Then, this choreography will be transformed into an orchestration. Thus, coherence between choreography and orchestration must be checked while showing the relation of conformity between these two different composition models. Indeed, this passage is accompanied by a verification phase. A set of properties will be preserved, the ones, which refer to the choreography and others, which are relative to those checked by the orchestration. Towards the end of this process, and in order to validate the transformation, we must check the maintained properties. This checking will be illustrated by the use of the model-checker, which depends on the properties

Towards Error-Handling-aware Choreography to Orchestration Transformation Approach

International audienc

Contributions à la théorie et aux applications des automates à multiplicités

Ce mémoire de thèse est un travail autour de publications en Informatique Théorique. Il contient deux contributions à la théorie des automates à Multiplicités, structure qui s'applique avec succès aux sciences voisines (Informatique, Mathématique, Physique, ). Un type particulier d'automates à multiplicités est constitué des automates avec -transitions notés k- -automates. Dans la première partie, on donne une méthode algébrique pour éliminer les -transitions de ces k- -automates afin d'obtenir un k-automate équivalent ayant le même comportement. Nous discutons les deux aspects du problème de l'étoile (par somme infinie et par équations). La théorie de la minimisation permet de minimiser un k-automate, au sens de réduire au maximum son nombre d'états tout en conservant le même comportement. Elle peut être utilisée, avec une légère modification, pour résoudre d'autres problèmes. Deux applications sont développées : dans un premier temps, on a utilisé cet algorithme de décomposition pour casser des fonctions booléennes, qui constituent l'élément non linéaire des algorithmes cryptographiques. La deuxième application consiste à décomposer des -modules où est l'algèbre de Hecke à q=0.This thesis is a work based on publications in Theoretical Computer Science. It consists of two contributions of the theory of automata with multiplicities. This structure has many applications to connected sciences (Computer Sciences, Mathematics, Physics, ). A particular type of automata with multiplicities is the automaton with -transitions denoted by k- -automaton. In the first part, we give an algebraic method for removing the -transitions of the k- -automaton in order to obtain an equivalent k-automaton with the same behaviour. We discuss two aspects of the star problem (by infinite sums and by equations). The theory of minimization allows to minimize a k-automaton in the sense of reducing to the smallest among the number of states. It can be used with some modification to solve other problems such as the splitting of modules. We have used the algorithm of decomposition to split a Boolean function which constitute the non linear element of the cryptographic algorithm and to split a -module where is the Hecke algebra as q=0.ROUEN-BU Sciences (764512102) / SudocROUEN-BU Sciences Madrillet (765752101) / SudocSudocFranceF

A Mechanism for the Causal Ordered Set Representation in Large-Scale Distributed Systems

International audienceDistributed systems have undergone a very fast evolution these last years. Large-scale distributed systems have become an integral part of everyday life with the development of new large-scale applications, consisting of thousands of computers and supporting millions of users. Examples include global Internet services, cloud computing systems, " big data " analytics platforms, peer-to-peer systems, wireless sensor networks and so on. The recent research addresses questions related to the way one may design, build, operate and maintain large-scale distributed systems. An other question related to such area, is how to represent causal dependencies in such systems in a minimal way. In general, causal dependencies can be established according to the Happened-Before Relation (HBR), which was introduced by Lamport. The HBR is a strict partial order, and therefore, one main problem linked to it is the combinatorial state explosion. The Immediate Dependency Relation (IDR) and the Causal Order Set Abstraction (CAOS) present a solution for such a problem. In this paper, we propose a mechanism which uses the concepts HBR, IDR, CAOS to model a large-scale distributed system execution in the form of the minimal graph (IDR graph) and the compact graph (CAOS graph). This mechanism is implemented in C++. The results of its execution are given here. The resultant causal graphs can be used for different purposes, such as for the design of more efficient algorithms, validation, verification, and/or the debugging of the existing ones, among others

Algebraic elimination of ε-transitions

We present here algebraic formulas associating a k-automaton to a k-ε-automaton. The existence depends on the definition of the star of matrices and of elements in the semiring k. For this reason, we present the theorem which allows the transformation of k-ε-automata into k-automata. The two automata have the same behaviour