Verifying service continuity in a satellite reconfiguration procedure: application to a satellite

The paper discusses the use of the TURTLE UML profile to model and verify service continuity during dynamic reconfiguration of embedded software, and space-based telecommunication software in particular. TURTLE extends UML class diagrams with composition operators, and activity diagrams with temporal operators. Translating TURTLE to the formal description technique RT-LOTOS gives the profile a formal semantics and makes it possible to reuse verification techniques implemented by the RTL, the RT-LOTOS toolkit developed at LAAS-CNRS. The paper proposes a modeling and formal validation methodology based on TURTLE and RTL, and discusses its application to a payload software application in charge of an embedded packet switch. The paper demonstrates the benefits of using TURTLE to prove service continuity for dynamic reconfiguration of embedded software

Choosing security elements for the xAAL home automation system

International audienceThe emergence of Internet of Things (IoT) and smart-home systems allows us to combine devices from different domains and to explore new usages and services. Unfortunately interoperability between devices from different technologies is a major issue to overcome before being able to offer smart services. For this purpose we have proposed the xAAL system. It is both a federating home-automation protocol and an open infrastructure designed to address issues caused by the heterogeneity of existing home-automation solutions. xAAL has been implemented, deployed and has proved its efficiency. However, early versions have been designed with functional concerns in mind. The time has come to address security. xAAL has its own specificities: a distributed system, multicast communications on a bus, etc. This paper details choices, compromises and motivations for selecting security elements that have been introduced in the new version of xAAL

A Transparent home Sensors/Actuators layer for Health & Well-being services

International audienceRisks factor leading to type 2 diabetes and cardiovascular diseases can be reduced by a preventive care infrastructure able to modify the habits toward healthier lifestyles, including more exercise, a better diet and a reduced stress. Accessing the home space is important not only to monitor indoor environment quality (IEQ) but also to provide relevant user's feedback and engage users towards a healthy life style. This paper present a new preventive care infrastructure composed of a distributed infrastructure for heterogeneous devices in the home local area network (named xAAL) in conjunction with a machine to machine protocol (MQTT) to external health & well-being services

Contribution à la conception de systèmes temps-réel s'appuyant sur la technique de description formelle RT-LOTOS

Ce mémoire de thèse s'intéresse à la conception de systèmes temps-réel en s'appuyant sur la méthode formelle RT-Lotos, extension temporelle à l'algèbre de processus Lotos. Il aborde plusieurs points relatifs à la spécification, la validation et l'ordonnancement de systèmes concurrents sujets à des contraintes logiques et temporelles. La première partie propose un éventail de méthodes formelles pour la spécification et la validation de systèmes temps-réel. Elle présente également le langage RT-Lotos et la technique de vérification formelle associée basée sur une analyse d'accessibilité. Elle détaille finalement un ensemble de travaux concernant l'automate temporisé (appelé un DTA) dérivé d'une spécification RT-Lotos, avec comme objectifs d'exécuter des simulations rapides, et de s'interfacer avec des outils de vérification de type model-checker. La deuxième partie présente une étude sur la notion de cohérence temporelle et propose une technique ainsi qu'un modèle formel pour exploiter sous un nouvel angle des informations issues de la vérification formelle par analyse d'accessibilité. Cette approche propose de raffiner le graphe des régions, d'en élaguer certaines branches jugées non souhaitables, d'extraire les dates de tir possible des actions, et de présenter ces informations sous la forme d'un nouveau type d'automate temporisé (appelé un TLSA) ayant pour vocation l'ordonnancement dans le temps des actions d'un système. Enfin, la troisième partie se penche sur les liens possibles entre méthodes formelles et semi-formelles. Dans ce cadre, nous proposons une sémantique formelle pour les diagrammes UML s'appuyant sur RT-Lotos, après avoir défini une extension temps-réel à UML appelée TURTLE). Ainsi, nous définissons une méthodologie qui s'inscrit dans les techniques de développement industriel classiques et qui permet une vérification formelle de systèmes temps-réel. ABSTRACT : This thesis deals with the design of real-time systems based on the RT-Lotos formal method, a timed extension to the Lotos process algebra. It addresses several issues related to the specification, validation and scheduling of concurrent systems subject to logical and temporal constraints. The first part of the work proposes a review of formal methods for the specification and validation of real-time systems. It also presents the RT-Lotos language and the associated formal verification technique based on reachability analysis. Finally, it details some works based on the timed automaton (called a DTA) derived from an RT-Lotos specification in order to carry out fast simulations, and to interface with model-checking tools. The second part presents a study on the concept of temporal consistency and proposes both a technique and a formal model to exploit in a new way the information resulting from the formal reachability analysis. This approach proposes to refine the regions graph, to remove paths considered to be nondesirable, to extract the firing instants of the actions, and to present this information in a new model of timed automaton (called a TLSA) which is able to schedule the execution of the actions of a system. Finally, the third part considers the possible relations between formal and nonformal methods. Within this framework, we propose a formal semantics for UML diagrams, after having defined a real-time extension to UML (called TURTLE). Thus, we define a methodology, which takes place inside traditional industrial development techniques and which allows a formal analysis of real-time systems

Decision Engine for SIP Based Dynamic Call Routing

Abstract. Enterprises nowadays are subscribing access to several Internet Service Providers (ISPs) for reliability, redundancy and better revenues underlying the service extension, while providing good Quality of Service (QoS). In this paper, a dynamic decision-making framework is presented for Session Initiation Protocol (SIP) based voice/video call routing in multihomed network. The decision engine takes multiple criteria into account while computing the routing decision (attributes from context of the request, platform's latest conditional parameters, business objectives of the company, etc.). Two Multi-Criteria Decision Making (MCDM) methods, namely Grey Relational Analysis (GRA) and an extended version of Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) are used for decision calculation in outsourcing and provisioning enforcement modes respectively. The proposed solution gives higher throughput and lower call dropping probability while fulfilling the desired goals, taking into account the multiple attributes for choosing the best alternative

MPTCP Solution for Seamless Local SIPTO Mobility

International audienceIn this paper, we propose a method to support seamless mobility for sessions carried by SIPTO connections. Session continuity has been considered an issue to be solved within 3GPP, as none of the solutions proposed for Mobile IP directly apply in the context of LTE. As in some cases, typically when SIPTO relies on using Local Gateways (LGW), it is necessary to change the IP address allocated to a User Equipment (UE), an active session may be interrupted. We propose an MPTCP based solution within the LTE architecture to maintain a single session, initially carried over a given SIPTO connection, and then carried over another SIPTO connection initiated due to the mobility of user equipment (UE). We identify how MPTCP operates over the LTE architecture, and estimate whether the corresponding delay is compatible with session continuity

UML and RT-LOTOS: an integration for real-time system validation

The paper presents a UML profile that overcomes the limitations of real-time solutions currently available on the market. Associations between classes are given a formal semantics. New temporal operators are introduced; they include a non deterministic delay and a time-limited offering. UML models can be validated against logical and timing constraints. The profile’s semantics is given through a translation into the formal language RT-LOTOS. The latter is supported by a validation tool which generates reachability graphs from extended UML models. A coffee machine serves as example in the paper. The profile is under evaluation on a satellite-based software reconfiguration system

Interaction with a Virtual Coach for Active and Healthy Ageing

International audienceSince life expectancy has increased significantly over the past century, society is being forced to discover innovative ways to support active aging and elderly care. The e-VITA project, which receives funding from both the European Union and Japan, is built on a cutting edge method of virtual coaching that focuses on the key areas of active and healthy aging. The requirements for the virtual coach were ascertained through a process of participatory design in workshops, focus groups, and living laboratories in Germany, France, Italy, and Japan. Several use cases were then chosen for development utilising the open-source Rasa framework. The system uses common representations such as Knowledge Bases and Knowledge Graphs to enable the integration of context, subject expertise, and multimodal data, and is available in English, German, French, Italian, and Japanese