Model-based testing of PLC programs with appropriate conformance relations

International audienceNumerous theoretical results have been obtained in the field of conformance testing, a very promising formal technique to improve dependability of critical systems. Nevertheless, developing on this basis PLC test techniques that produce correct conformance verdicts requires to take into account the real technological features of PLC. This paper proposes conformance relations that meet this objective. Examples illustrate the benefits of the contribution

A Discrete event model for multiple inhabitants location tracking

6 pagesInternational audienceSmart Home technologies are aiming to improve the comfort and safety of the inhabitants into their houses. To achieve this goal, online indoor location tracking of the inhabitants is often used to monitor the air conditioning, to detect dangerous situations and for many other applications. In this paper, it is proposed an approach to build a model allowing dynamic tracking of several persons in their house. A method to construct such a model by using finite automata and Discrete Event System (DES) paradigms is presented. An approach to reduce the size of the model is also introduced. Finally, an efficient algorithm for location tracking is proposed. For the sake of better understanding, an illustrative example is used throughout the paper

Circadian Rhythm and Sleep Disruption: Causes, Metabolic Consequences and Countermeasures.

Circadian (∼ 24 hour) timing systems pervade all kingdoms of life, and temporally optimize behaviour and physiology in humans. Relatively recent changes to our environments, such as the introduction of artificial lighting, can disorganize the circadian system, from the level of the molecular clocks that regulate the timing of cellular activities to the level of synchronization between our daily cycles of behaviour and the solar day. Sleep/wake cycles are intertwined with the circadian system, and global trends indicate that these too are increasingly subject to disruption. A large proportion of the world's population is at increased risk of environmentally-driven circadian rhythm and sleep disruption, and a minority of individuals are also genetically predisposed to circadian misalignment and sleep disorders. The consequences of disruption to the circadian system and sleep are profound and include myriad metabolic ramifications, some of which may be compounded by adverse effects on dietary choices. If not addressed, the deleterious effects of such disruption will continue to cause widespread health problems; therefore, implementation of the numerous behavioural and pharmaceutical interventions that can help restore circadian system alignment and enhance sleep will be important

Commutations sûres de mode pour les systèmes à événements discrets

The work presented in this thesis concerns a framework applied to the modal approach for discrete-event system (DES). A mode is a particular configuration of a system where this one handles a set of components and has to respect a set of specifications. The problem of mode management is about the design of modes and on their switching. The aim of our work is to propose a, completely defined, designing framework, where the specifications are guaranteed, and only the admissible switching between modes may happen. It also verifies that every switching in a mode effectively leads to safely another one. To reach this goal, we firstly use the Supervisory Control Theory (SCT) which computes safe models in which the requirements are respected. The proposed framework is composed by several steps, splitting the different studies of design. The first step focuses on the formalization of requirements into mathematical models - Finite State Machine. The next one concerns the synthesis by SCT of the internal behavior of mode to ensure that the specifications are respected, independently of other modes. The third step studies the switching behavior such as the switching specifications in each mode are respected. In this step, the admissible switchings are specified and forbid the other ones. The next step is a function of process tracking which verifies that all switchings effectively lead into only one mode. In the opposite case, the function of process tracking identifies and characterizes the problematic switchings to help the designer to solve these possibilities. At the end, a step of merging states is computed to remove the non-significant states and obtaining one model per mode representing the behavior of this one. To show the applicability of the proposed framework, we apply it on an example used in the literature.Le travail présenté dans ce mémoire concerne une démarche de conception appliquée à une gestion modale pour les systèmes à événements discrets (SED). Un mode est une configuration particulière du système où celui-ci exploite un ensemble de composants et doit respecter un ensemble de spécifications. La problématique de la gestion de mode porte principalement sur la conception des modes et sur leurs commutations. Notre objectif est de proposer une démarche de conception complètement définie où les spécifications sont assurément respectées, et où seules les commutations désirées entre modes peuvent se produire. Il est également vérifié que toute commutation dans un mode mène de manière sûre dans un autre mode. Pour réaliser cet objectif, nous utilisons la théorie de contrôle par supervision qui permet de concevoir des modèles sûrs par construction tel que les spécifications utilisées pour la construction soient respectées. La démarche proposée possède plusieurs étapes séparant ainsi les différentes études de conception. La première concerne la formalisation du cahier des charges en modèles automate à états. L'étude suivante concerne le comportement interne où celui-ci doit respecter les spécifications propres aux modes, indépendamment des autres modes. Cette étape valide le comportement de chaque mode, avant d'étudier leurs commutations. La troisième étape étudie le comportement commutatif tel que les spécifications de commutations soient respectées. Cette étape spécifie les commutations désirées, et inversement celles non voulues. L'étape suivante est l'exécution d'une fonction de suivi de trajectoire qui vérifie que toutes les commutations mènent bien dans un autre mode. Dans le cas contraire, la fonction de suivi identifie et caractérise les commutations problématiques afin d'aider le concepteur dans la résolution de ces situations. Enfin, une étape de fusion d'états finalise la démarche afin de fournir un modèle par mode qui représente le comportement de celui-ci. Pour montrer l'applicabilité de la démarche proposée, et sa faculté à être utilisée en milieu industriel, nous l'utilisons sur un exemple de taille importante utilisée dans la littérature

Automated Generation of Models of Activities of Daily Living

International audienceIn order to increase the safety of autonomous elderly people in their home, Ambient Assisted Living technologies are currently emerging. Namely, the recognition of their activities might be a way to detect eventual health problems, and can be performed in a Smarthome equipped with binary sensors. Hence, this communication aims at providing means to automatically generate a formal model of the Activities of Daily Living. A data mining approach in order to discover frequent habits of the observed inhabitant from a database of sequences of sensor events is proposed. Those frequent habits are then formally modelled using finite automata, leading to the construction of a map of habits mirroring the behaviour of the inhabitant. Such a model could then be used for online identification of habits, and even predictions of the upcoming behaviour. Results obtained on a case study are also presented

Mathematical Criteria for a Priori Performance Estimation of Activities of Daily Living Recognition

Monitoring Activities of Daily Living (ADL) has become a major occupation to respond to the aging population and prevent frailty. To do this, the scientific community is using Machine Learning (ML) techniques to learn the lifestyle habits of people at home. The most-used formalism to represent the behaviour of the inhabitant is the Hidden Markov Model (HMM) or Probabilistic Finite Automata (PFA), where events streams are considered. A common decomposition to design ADL using a mathematical model is Activities–Actions–Events (AAE). In this paper, we propose mathematical criteria to evaluate a priori the performance of these instrumentations for the goals of ADL recognition. We also present a case study to illustrate the use of these criteria

Equivalence of Behaviors Between Centralized and Multi-model Approaches

Abstract — This paper presents a comparison between centralized approach and multi-model approach based on Supervisory Control Theory (SCT). The centralized approach uses both the whole process and specification to compute the controlled process. The multi-model approach, on the other hand, is used basing on various modal perspectives. This approach allows to build smaller models, which lead to smaller scale and better understanding of the latter. The comparison is made basing on a number of conditions, which all ensure the identical behavior between the controlled processes of each discussed approach. An example of a manufacturing system illustrating the comparison is also presented. I

Identification des états équivalents dans l'approche modale

International audienceCe papier présente une extension de la fonction de suivi de trajectoire pour identifier les états compatibles entre modes. La fonction de suivi de trajectoire a pour but d'assurer que les commutations entre modes soient sûres. Utilisée dans une démarche d'aide à la conception se basant sur la Théorie de Contrôle par Supervision (TCS), les spécifications sont formellement assurées. Cependant, les modèles manipulés sont des automates à états émondés et il a été mise en évidence que certains états non-accessibles, donc supprimés pour obtenir un automate émondé, étaient accessibles depuis un autre mode par une commutation. L'extension que nous proposons s'appuie sur les automates non-émondés et propose une comparaison formelle sur les noms des états pour déterminer les états accessibles depuis d'autres modes

Life Habits Modeling with Stochastic Timed Automata in Ambient Assisted Living

International audienceRecent improvements in connected tools and learning algorithms allow new opportunities in the field of Ambient Assisted Living (AAL). However, smart home inhabitant's life habits are often required to obtain adequate results for energy management, security, Health at Home (HaH), and numerous other applications. In this paper, a model for life routines representation and algorithms for its generation is introduced. Study on the state of the art exposes that activity ordering and duration are key features of human behavior. Consequently, the presented approach focuses on a higher level of semantic by observing activities performed by the inhabitant rather than the sensor logs, which allow for better understanding of his comportment and universality of the model for multiple aims. Stochastic Time Automata (STA) is proposed as it adequately models activity ordering with probability associated to edges and activity duration through probability distribution associated to location delay. Presented approach does not require specific equipment besides sensors required for activity recognition and is versatile enough to be used in various applications. A case study highlights the relevancy of the chosen features and demonstrates that the proposed model is efficient to depict and understand inhabitants' life habits