Modelling interdependencies between the electricity and information infrastructures

The aim of this paper is to provide qualitative models characterizing interdependencies related failures of two critical infrastructures: the electricity infrastructure and the associated information infrastructure. The interdependencies of these two infrastructures are increasing due to a growing connection of the power grid networks to the global information infrastructure, as a consequence of market deregulation and opening. These interdependencies increase the risk of failures. We focus on cascading, escalating and common-cause failures, which correspond to the main causes of failures due to interdependencies. We address failures in the electricity infrastructure, in combination with accidental failures in the information infrastructure, then we show briefly how malicious attacks in the information infrastructure can be addressed

An architecture-based dependability modeling framework using AADL

For efficiency reasons, the software system designers' will is to use an integrated set of methods and tools to describe specifications and designs, and also to perform analyses such as dependability, schedulability and performance. AADL (Architecture Analysis and Design Language) has proved to be efficient for software architecture modeling. In addition, AADL was designed to accommodate several types of analyses. This paper presents an iterative dependency-driven approach for dependability modeling using AADL. It is illustrated on a small example. This approach is part of a complete framework that allows the generation of dependability analysis and evaluation models from AADL models to support the analysis of software and system architectures, in critical application domains

Software dependability modeling using an industry-standard architecture description language

Performing dependability evaluation along with other analyses at architectural level allows both making architectural tradeoffs and predicting the effects of architectural decisions on the dependability of an application. This paper gives guidelines for building architectural dependability models for software systems using the AADL (Architecture Analysis and Design Language). It presents reusable modeling patterns for fault-tolerant applications and shows how the presented patterns can be used in the context of a subsystem of a real-life application

Fiabilité opérationnelle des avoins (Approche basée sur les modèles et cas d'étude)

Lors de la conception des avions, il est courant que les constructeurs évaluent la sûreté de fonctionnement en utilisant des modèles stochastiques, mais l'évaluation de la fiabilité opérationnelle à l aide de modèles en ligne, pendant la réalisation des missions, reste rarement effectuée. Souvent, l'évaluation stochastique concerne la sécurité des avions. Cette thèse porte sur la modélisation de la fiabilité opérationnelle des avions, pour aider à la planification des activités de maintenance et des missions, ainsi qu à la bonne réalisation de ces dernières. Nous avons développé une approche de modélisation, basée sur un méta-modèle qui sert de base i) de structuration des informations nécessaires à l évaluation de la fiabilité opérationnelle d un avion et ii) pour la construction de modèles stochastiques pouvant être mis à jour dynamiquement. La mise à jour concerne l'état courant des systèmes avion, un profil de mission et les moyens de maintenance disponibles dans les diverses escales incluses dans le profil de la mission. L'objectif est de permettre l'évaluation de la fiabilité opérationnelle en ligne. Deux cas d études, basés sur des sous-systèmes avion, sont considérés à titre d'illustration. Nous présentons des exemples de résultats qui montrent le rôle important de l évaluation de la fiabilité opérationnelle pendant une mission d avionDependability assessment, by system manufacturer, during aircraft design, based on stochastic modeling, is of common practice, but model based operational dependability assessment online, during missions' achievement, is seldom done. Usually, the stochastic assessment addresses aircraft safety.This thesis addresses aircraft operational dependability modeling to support mission and maintenance planning, as well as the achievement of the missions. We develop a modeling approach, based on a meta-model that is used as a basis i) to structure the information needed to assess aircraft operational reliability and ii) to build a stochastic model that can be updated dynamically. The update concerns the current state of the aircraft system, a mission profile and the maintenance facilities available at the flight stop locations involved in the mission. The aim is to enable operational reliability assessment online. Two case studies, based on aircraft subsystems, are considered for illustration. We present examples of evaluation results that show the valuable role of operational dependability assessment during aircraft missionTOULOUSE-INSA-Bib. electronique (315559905) / SudocSudocFranceF

Resilient Computing Curriculum

This Deliverable presents the MSc Curriculum in Resilient Computing suggested by ReSIST. It includes the description of the syllabi for all the courses in the two semesters of the first year, those for the common courses in semester 3 in the second year together with an exemplification of possible application tracks with the related courses. This MSc curriculum has been updated and completed taking advantage of a large open discussion inside and outside ReSIST. This MSc Curriculum is on-line on the official ReSIST web site, where all information is available together with all the support material generated by ReSIST and all other relevant freely available support material.European Commission through NoE IST-4-026764-NOE (ReSIST

Resilient Computing Courseware

This Deliverable describes the courseware in support to teaching Resilient Computing in a Curriculum for an MSc track following the scheme of the Bologna process. The development of the supporting material for such a curriculum has required a rather intensive activity that involved not only the partners in ReSIST but also a much larger worldwide community with the aim of identifying available updated support material that can be used to build a progressive and methodical line of teaching to accompany students and interested persons in a profitable learning process. All this material is on-line on the official ReSIST web site http://www.resistnoe.org/, can be viewed and downloaded for use in a class and constitutes, at our knowledge, the first, almost comprehensive attempt, to build a database of support material related to Dependable and Resilient Computing.European Commission through NoE IST-4-026764-NOE (ReSIST

Croissance de la sûreté de fonctionnement des logiciels. Caractérisation, modélisation, évaluation

This thesis is dedicated to software dependability evaluation.Dans ce mémoire nous nous intéressons à l'évaluation de la sûreté de fonctionnement d'un système informatique et plus particulièrement du logiciel. Nous considérons à la fois les aspects de fiabilité (prise en compte des temps hors défaillance uniquement) et de disponibilité (prise en compte simultanée des temps hors défaillance et des temps où le système est défaillant. Nous nous intéressons à la sûreté de fonctionnement d'un logiciel déjà codé et qui est en cours d'évolution. cette évolution a pour origine soit des corrections, soit des changements de spécifications, situation couramment appelé "croissance de fiabilité

Evaluation de la sûreté de fonctionnement des systèmes de sécurité - Application à la commande des postes à très haute tension

The thesis is dedicated to the evlaution of the dependability of safety systems. The main property of such systems is dormance: some functions are activated only in case of an external incident. In case of incident occurrence, serious injuries may affect the environment. Due to dormance, several failures may accumulate without being detected, and thay can be activated only in case of an incident. The aim of the theis id to define new architectures, tolerant to dormance failures, based on dependability evaluation.Le mémoire traite de l'évaluation de la sûreté de fonctionnement de systèmes de sécurité,. La propriété principale de ces systèmes est la dormance : certaines fonctions ne sont sollicitées que très rarement, suite à un incident extérieur. Si le système ne réagit pas immédiatement à l'incident, des conséquences graves sur l'environnement peuvent avoir lieu. Ainsi des défaillances peuvent s'accumuler dans le système et ne pourront être révélées que lors de leur sollicitation. Partant du système actuel, comme référence, nous proposons une méthode d'évaluation de sa sûreté , basée sur les processus de Markov. Nous définissons ensuite un ensemble d'architectures tolérantes aux fautes et nous comparons leur fiabilité, dans l'objectif de définir de nouvelles architectures tolérantes aux fautes

A Measurement-Based Framework for Software Reliability Improvement

Programs for software reliability improvement based on measurements require the collection and analysis of comprehensive and consistent data sets on several software projects. In this paper, we put emphasis on data collection and analysis programs for software reliability improvement. We first present the objectives of data collection programs, report some success stories related to software reliability improvement, then discuss the practical aspects of data collection, validation and processing before giving recommendations for successful data collection and analysis programs. The success stories show that the gain in productivity and reliability is obtained at almost no extra cost, and even with an overall cost reduction most of the time. Data processing consists in performing statistical treatments. For reliability purposes, we consider three main activities: descriptive analysis, trend analysis, and reliability evaluation. The recommendations and examples of results, given at the end of the paper, are based on our experience in processing failure data collected on real-life software systems. We discuss in particular, the relevance of software reliability evaluation according to the life-cycle phase considered.