Développement sans rupture de systèmes complexes : une approche basée multi-exigences

Prouver qu'un système satisfait à ses exigences est un défi important de l'ingénierie des exigences. D'une part, les approches formelles fournissent un moyen d'exprimer les exigences mathématiquement et de prouver qu'un système satisfait ses exigences. Cependant, si la formalisation offre des possibilités supplémentaires telles que la vérification, voire la validation, elle s'avère souvent trop difficile à utiliser en pratique par les acteurs impliqués dans le développement des systèmes. D'autre part, dans la plupart des cas, les exigences sont écrites et parfois tracées en langage naturel à des fins de communication et de compréhension mutuelle. De plus, cela reste le cas tout au long du processus de développement. Ainsi, il est nécessaire de considérer le besoin de s'adresser à toutes ces parties prenantes pendant le processus de développement. L'objectif principal de cette thèse est de fournir une méthodologie sans rupture qui permet de bénéficier de la formalisation des exigences tout en étant compréhensible par toutes les parties prenantes. Nous proposons une approche qui considère les exigences comme des parties du code du système, ce qui, en tant que tel, contribue à améliorer l'évaluation de la qualité. De plus, l'intégration des exigences dans le code garantit un développement sans rupture. Ces contributions visent trois avantages principaux. Premièrement, il n'est pas nécessaire de passer d'un outil ou d'un environnement à un autre : un cadre unique prend en charge le développement de l'analyse à la mise en œuvre. Deuxièmement, les changements et la réversibilité deviennent un phénomène régulier, directement pris en charge par la méthode, le langage et les outils, ce qui facilite les allers-retours. Enfin, les différents niveaux d'abstraction restent dans le cadre du paradigme orienté objet. Nous appliquons cette vision au processus de développement lui-même avec les mêmes avantages attendus. Le cycle de vie du développement peut alors bénéficier de cette forte intégration des exigences dans le code. Ces artefacts aident au développement du logiciel en fournissant un support et des lignes directrices pour l'analyse ou l'aide à la décision et en renforçant la qualité du logiciel. En outre, la réutilisabilité, l'évolutivité et la maintenabilité sont améliorées. La traçabilité entre les exigences et le code permet une analyse d'impact facile lorsque l'un de ces artefacts évolue. Cependant, si ce paradigme est familier aux développeurs et même si nous faisons un effort d'expressivité, il ne s'adresse pas aux autres parties prenantes qui ont l'habitude de travailler avec d'autres outils. Puisque nous souhaitons également que des non-experts utilisent notre approche pour valider des systèmes dans la première phase de leur développement, nous proposons un langage spécifique au domaine : (i) proche du langage naturel et (ii) basé sur une sémantique formelle. En utilisant les techniques de l'ingénierie dirigée par les modèles, ce langage permet de combler le fossé entre les différents acteurs impliqués dans un projet (compte tenu de leurs différentes expériences) et entre les exigences et le code. Nous avons enfin consacré un effort de recherche à la définition des relations entre les exigences. Nous fournissons leurs définitions formelles et leurs propriétés sur la propagation de l'état de satisfaction. Ces définitions peuvent aider les ingénieurs à vérifier les exigences (en vérifiant la validité de la sémantique des relations entre deux exigences) et à vérifier la conformité du système (grâce à la propagation de la satisfaction). Ce travail est une étape vers l'introduction de la sémantique formelle dans la traçabilité, permettant d'analyser automatiquement les exigences et d'utiliser leurs relations pour vérifier l'implémentation correspondante du système.Proving that a system satisfies its requirements is an important challenge of Requirements Engineering. On the one hand, formal approaches provide a way to express requirements mathematically and prove that a system satisfies its requirements. However, if formalization offers additional possibilities such as verification, or even validation, it often proves to be too difficult to use in practice by the stakeholders involved in the development of systems. On the other hand, in most cases, requirements are written and sometimes traced in Natural Language for communication and mutual understanding purposes. Moreover, this remains during the whole development process. Thus, it is necessary to consider the need to address all these stakeholders during the development process. The main objective of this thesis is to provide a seamless methodology that allows benefiting from the formalization of requirements while being understandable by all stakeholders. We propose an approach that considers requirements as parts of the system's code, which, as such, contributes to improving quality assessment. In addition, integrating the requirements into the code guarantees a seamless development. The contributions target three main benefits. First, there is no need to switch from one tool or environment to another: a single framework supports the development from analysis to implementation. Second, changes and reversibility become a regular occurrence, directly supported by the method, language, and tools, facilitating round-trips. Third, the different levels of abstraction remain inside the object-oriented paradigm. We apply this vision to the development process itself with the same expected advantages. The development life-cycle can then benefit from this strong integration of requirements into the code. These artifacts help in software development by providing support and guidelines for analysis or decision support and reinforcing the software quality. Besides, reusability, evolutivity, and maintainability are enhanced. Traceability between requirements and code allows an easy impact analysis when any of these artifacts evolve. However, if this paradigm is familiar to developers and even if we put an effort in providing expressivity, they are not addressed to other stakeholders that used to work with several tools. Since we also want non-experts to use our approach to validate systems in the early stage of their development, we propose a Domain-Specific Language: (i) close to natural language and (ii) based on formal semantics. Using Model-Driven Engineering techniques, this language bridges the gap between the several stakeholders involved in a project (considering their different backgrounds) and between the requirements and the code. We finally put a research effort into defining relationships between requirements. We provide their formal definitions and properties on the propagation of the satisfaction state. These definitions can help engineers verify requirements (by checking the validity of the semantics of the relationships between two requirements) and verify the system compliance (thanks to satisfaction propagation). This work is a step towards introducing formal semantics into traceability, making it possible to automatically analyze requirements and use their relationships to verify the corresponding implementation of the system

Extending relational model transformations to better support the verification of increasingly autonomous systems

Over the past decade the capabilities of autonomous systems have been steadily increasing. Unmanned systems are moving from systems that are predominantly remotely operated, to systems that include a basic decision making capability. This is a trend that is expected to continue with autonomous systems making decisions in increasingly complex environments, based on more abstract, higher-level missions and goals. These changes have significant implications for how these systems should be designed and engineered. Indeed, as the goals and tasks these systems are to achieve become more abstract, and the environments they operate in become more complex, are current approaches to verification and validation sufficient? Domain Specific Modelling is a key technology for the verification of autonomous systems. Verifying these systems will ultimately involve understanding a significant number of domains. This includes goals/tasks, environments, systems functions and their associated performance. Relational Model Transformations provide a means to utilise, combine and check models for consistency across these domains. In this thesis an approach that utilises relational model transformation technologies for systems verification, Systems MDD, is presented along with the results of a series of trials conducted with an existing relational model transformation language (QVT-Relations). These trials identified a number of problems with existing model transformation languages, including poorly or loosely defined semantics, differing interpretations of specifications across different tools and the lack of a guarantee that a model transformation would generate a model that was compliant with its associated meta-model. To address these problems, two related solvers were developed to assist with realising the Systems MDD approach. The first solver, MMCS, is concerned with partial model completion, where a partial model is defined as a model that does not fully conform with its associated meta-model. It identifies appropriate modifications to be made to a partial model in order to bring it into full compliance. The second solver, TMPT, is a relational model transformation engine that prioritises target models. It considers multiple interpretations of a relational transformation specification, chooses an interpretation that results in a compliant target model (if one exists) and, optionally, maximises some other attribute associated with the model. A series of experiments were conducted that applied this to common transformation problems in the published literature

Design of the Electronics Subsystem for a High-Resolution Electro-Optical Payload Using Systems Engineering Approach

Satellite imagers, in contrast to commercial imagers, demand exceptional performance and operate under harsh conditions. The camera is an essential part of an Earth Observation Electro Optical (EO) payload that is designed in response to needs such as military demands, changes in world politics, inception of new technologies, operational requirements and experiments. As one of the key subsystems, the Imager Electronics Subsystem of a high-resolution EO payload plays very important role in the accomplishment of mission objectives and payload goals. Hence, these Electronics Subsystems require a special design approach optimised for their needs and meticulous characterizations of high-resolution space applications. This dissertation puts forward the argument that the system being studied is a subsystem of a larger system and that systems engineering principles can be applied to the subsystem design process also. The aim of this dissertation is to design the Imager Electronics Subsystem of a high-resolution Electro Optical Payload using a systems engineering approach to represent a logical integration and test flow using the space industry guidelines. The Imager Electronics Subsystem consists of group of elements forming the functional chain from the Image Sensors on the Focal Plane down to electrical interface to the Data Handling Unit and power interface of the satellite. This subsystem is responsible for collecting light in different spectral bands, converting this light to data of different spectral bands from image sensors for high-resolution imaging, performing operations for aligning, tagging and multiplexing along with incorporating internal and external interfaces

Intensional Cyberforensics

This work focuses on the application of intensional logic to cyberforensic analysis and its benefits and difficulties are compared with the finite-state-automata approach. This work extends the use of the intensional programming paradigm to the modeling and implementation of a cyberforensics investigation process with backtracing of event reconstruction, in which evidence is modeled by multidimensional hierarchical contexts, and proofs or disproofs of claims are undertaken in an eductive manner of evaluation. This approach is a practical, context-aware improvement over the finite state automata (FSA) approach we have seen in previous work. As a base implementation language model, we use in this approach a new dialect of the Lucid programming language, called Forensic Lucid, and we focus on defining hierarchical contexts based on intensional logic for the distributed evaluation of cyberforensic expressions. We also augment the work with credibility factors surrounding digital evidence and witness accounts, which have not been previously modeled. The Forensic Lucid programming language, used for this intensional cyberforensic analysis, formally presented through its syntax and operational semantics. In large part, the language is based on its predecessor and codecessor Lucid dialects, such as GIPL, Indexical Lucid, Lucx, Objective Lucid, and JOOIP bound by the underlying intensional programming paradigm.Comment: 412 pages, 94 figures, 18 tables, 19 algorithms and listings; PhD thesis; v2 corrects some typos and refs; also available on Spectrum at http://spectrum.library.concordia.ca/977460

Tools and Algorithms for the Construction and Analysis of Systems

This open access book constitutes the proceedings of the 28th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2022, which was held during April 2-7, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 46 full papers and 4 short papers presented in this volume were carefully reviewed and selected from 159 submissions. The proceedings also contain 16 tool papers of the affiliated competition SV-Comp and 1 paper consisting of the competition report. TACAS is a forum for researchers, developers, and users interested in rigorously based tools and algorithms for the construction and analysis of systems. The conference aims to bridge the gaps between different communities with this common interest and to support them in their quest to improve the utility, reliability, exibility, and efficiency of tools and algorithms for building computer-controlled systems

Safety and Reliability - Safe Societies in a Changing World

The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen

Tools and Algorithms for the Construction and Analysis of Systems

This open access book constitutes the proceedings of the 28th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2022, which was held during April 2-7, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 46 full papers and 4 short papers presented in this volume were carefully reviewed and selected from 159 submissions. The proceedings also contain 16 tool papers of the affiliated competition SV-Comp and 1 paper consisting of the competition report. TACAS is a forum for researchers, developers, and users interested in rigorously based tools and algorithms for the construction and analysis of systems. The conference aims to bridge the gaps between different communities with this common interest and to support them in their quest to improve the utility, reliability, exibility, and efficiency of tools and algorithms for building computer-controlled systems