The interaction of embedded systems with their environments and their resource limitations make it important to take into account properties such as timing, security, and resource consumption in designing such systems. These so-called Extra-Functional Properties (EFPs) capture and describe the quality and characteristics of a system, and they need to be taken into account from early phases of development and throughout the system's lifecycle. An important challenge in this context is to ensure that the EFPs that are defined at early design phases are actually preserved throughout detailed design phases as well as during the execution of the system on its platform. In this thesis, we provide solutions to help with the preservation of EFPs; targeting both system design phases and system execution on the platform. Starting from requirements, which form the constraints of EFPs, we propose an approach for modeling Non-Functional Requirements (NFRs) and evaluating different design alternatives with respect to the satisfaction of the NFRs. Considering the relationship and trade-off among EFPs, an approach for balancing timing versus security properties is introduced. Our approach enables balancing in two ways: in a static way resulting in a fixed set of components in the design model that are analyzed and thus verified to be balanced with respect to the timing and security properties, and also in a dynamic way during the execution of the system through runtime adaptation. Considering the role of the platform in preservation of EFPs and mitigating possible violations of them, an approach is suggested to enrich the platform with necessary mechanisms to enable monitoring and enforcement of timing properties. In the thesis, we also identify and demonstrate the issues related to accuracy in monitoring EFPs, how accuracy can affect the decisions that are made based on the collected information, and propose a technique to tackle this problem. As another contribution, we also show how runtime monitoring information collected about EFPs can be used to fine-tune design models until a desired set of EFPs are achieved. We have also developed a testing framework which enables automatic generation of test cases in order verify the actual behavior of a system against its desired behavior. On a high level, the contributions of the thesis are thus twofold: proposing methods and techniques to 1) improve maintenance of EFPs within their correct range of values during system design, 2) identify and mitigate possible violations of EFPs at runtime. / CHESS / MBAT / ITS-EASY

Progress

The complexity of modern systems is continuously growing, thus demanding novel powerful development approaches.In this direction, model-driven and component-based software engineering have reached the status of promising paradigms for the development of complex systems. Moreover, in the embedded domain, their combination is believed to be helpful in handling the ever-increasing complexity of such systems.However, in order for them and their combination to definitively break through at industrial level, code generated from models through model transformations should preserve system properties modelled at design level. This research work focuses on aiding the preservation of system properties throughout the entire development process across different abstraction levels. Towards this goal, we provide the possibility of analysing and preserving system properties through a development chain constituted of three steps: (i) generation of code from system models, (ii) execution and analysis of generated code, and (iii) back-propagation of analysis results to system models.With the introduction of steps (ii) and (iii), properties that are hard to predict at modelling level are compared with runtime values and this consequently allows the developer to work exclusively at modelling level thus focusing on optimising system models with the help of those values. / Denna doktorsavhandling presenterar nya och förbättrade tekniker för modelldriven och komponentbaserad utveckling av programvara. Syftet är att bevara systemegenskaper, som specificerats i modeller, genom de olika stadierna av utvecklingen och när modeller översätts mellan olika abstraktionsnivåer och till kod. Vi introducerar möjligheter att studera och bevara systemets egenskaper genom att skapa en kedja i tre steg som: (i) genererar kod från systemmodellen, (ii) exekverar och analyserar den genererade koden och (iii) slutligen återkopplar analysvärden till systemmodellen. Introduktionen av steg (ii) och (iii) gör det möjligt att genomföra en detaljerad analys av egenskaper som är svåra, eller till och med omöjliga, att studera med hjälp av endast systemmodeller. Fördelen med det här tillvägagångssättet är att det förenklar för utvecklaren som slipper arbeta direkt med kod för att ändra systemegenskaper. Istället kan utvecklaren arbeta helt och hållet med modeller och fokusera på optimering av systemmodeller med hjälp av analysvärden från testkörningar av systemet. Vi är övertygade om att denna typ av teknik är nödvändig att utveckla för att stödja modelldriven utveckling av programvara eftersom dagens tekniker inte möjliggör för systemutvecklare att specificera, analysera och optimera systemegenskaper på modellnivå. / La continua crescita in complessitá dei sistemi software moderni porta alla necessitá di definire nuovi e piú efficaci approcci di sviluppo. In questa direzione, metodi basati su modelli (model-driven engineering) e componenti (component-based software engineering) sono stati riconosciuti come promettenti nuove alternative per lo sviluppo di sistemi complessi. Inoltre l'interazione tra loro é ritenuta particolarmente vantaggiosa nella gestione nello sviluppo di sistemi integrati. Affinché questi approcci, cosí come la loro interazione, possano definitivamente prendere piede in campo industriale, il codice generato dai modelli tramite apposite transformazioni deve essere in grado di preservare le proprietá di sistema, sia funzionali che extra-funzionali, definite nei modelli. Il lavoro di ricerca presentato in questa tesi di dottorato si focalizza sul preservamento delle proprietá di sistema nell'intero processo di sviluppo e attraverso i diversi livelli di astrazione. Il risultato principale é rappresentato da un approccio automatico di round-trip engineering in grado di sostenere il preservamento delle proprietá di sistema attraverso: 1) generazione automatica di codice, 2) monitoraggio e analisi dell'esecuzione del codice generate su piattaforme specifiche, e 3) offrendo la possibilitá di propagare verticalmente i risultati da runtime al livello di modellazione. In questo modo, quelle proprietá che possono essere stimate staticamente solo in maniera approssimativa, vengono valutate in rapporto ai valori ottenuti a runtime. Ció permette di ottimizzare il sistema a livello di design attraverso i modelli, piuttosto che manualmente a livello di codice, per assicurare il preservamento degli proprietá di sistema d'interesse.

This thesis is focused on the attributes concept of ProCom, a component model developed within The Progress Centre for Predictable Embedded Software Systems. Attributes are pieces of information of various types and levels of abstraction associated with the ProCom entities during the development of a system. Based on the analysis of the development process envisioned by Progress, the requirements for the attributes of ProCom entities are identified, and various alternatives of realizing attributes are analyzed. The chosen solution of highly structured, multi-valued, and extensible attributes is elaborated. The thesis also consists of the design and the prototype implementation of an attribute framework realizing and proving the feasibility of the proposed concepts. The framework addresses the needs of all actors involved in working with attributes throughout the development of a system: It provides an extensible, modular GUI for viewing and editing possibly highly complex information contained in attributes, an interface for the programmatic access to attributes, and well-defined mechanisms for extending the attribute pool by new attributes, new attribute types, and means for their manipulation. The framework is integrated into the main tool supporting the Progress development, the Progress IDE. / Progress

Model-driven and component-based software engineering have been widely recognized as promising paradigms for development of a wide range of systems. Moreover, in the embedded real-time domain, their combination is believed to be helpful in handling the ever-increasing complexity of such systems design.However, in order for these paradigms and their combination to definitely break through at an industrial level for development of embedded real-time systems, both functional and extra-functional properties need to be addressed at each level of abstraction. This research focuses on the preservation of extra-functional properties. More specifically, the aim is to provide support for easing such preservation throughout the entire development process at different abstraction levels.The main outcome of the research work is a round-trip engineering approach aiding the preservation of extra-functional properties by providing code generators, supporting monitoring and analysis of code execution, and then enabling back-propagation of the results to modelling level. In this way, properties that can only be roughly estimated statically are evaluated against runtime values and this consequently allows to optimize the design models for ensuring preservation of analysed extra-functional properties. Moreover, a solution for managing evolution of computational context in which extra-functional properties are defined by means of validity analysis is provided. Such solution introduces a new language for the description of the computational context in which a given property is provided and/or computed by some analysis, enables detection of changes performed to the context description, and analyses the possible impacts on the extra-functional property values based on a precise representation of differences between previous and current version of the model.

Progress

L’accroissement continu de la complexité des systèmes embarqués pose un problème majeur pour leur développement lequel doit aussi prendre en compte les exigences extra-fonctionnelles et les contraintes du domaine telles que la limitation et le partage des ressources, la distribution, et les contraintes temporelles et de fiabilité. De ce fait, les systèmes embarqués requièrent de nouvelles solutions pouvant efficacement et de manière prévisible répondre à l’ensemble de ces besoins. L’ingénierie logicielle basée composants est un paradigme qui a déjà démontré des aptitudes pour appréhender la complexité logicielle. Cependant, pour supporter de manière efficace les propriétés extra-fonctionnelles, un modèle de composants doit posséder des mécanismes spécifiques. L’objectif de cette thèse est de construire un tel support. Pour ce faire, nous avons analysé de manière systématique des modèles de composants existants à ce jour et identifié des challenges relatifs à la réalisation d’une approche basée composants dédiée au développement des systèmes embarqués. S’appuyant sur ces challenges, nous avons avancé l’état de l’art en développant ProCom, un nouveau modèle de composants qui répond aux attentes des systèmes embarqués au travers de sa sémantique d’exécution et de sa structuration en niveaux. Centré autour de ProCom, nous avons aussi développé PRIDE, son environnement de développement intégré. PRIDE couvre le procédé de développement des premières phases de spécification jusqu’à la synthèse et le déploiement et fournit des moyens d’intégrer différents outils d’analyse et de vérification. La contribution principale de cette thèse réside dans la modélisation et la réalisation d’un support pour la gestion des propriétés extra-fonctionnelles pour les systèmes embarqués construits à base de composants logiciels. Ce support facilite la spécification, le management et l’intégration de propriétés multi-valuées tenant compte du contexte dans lequel elles ont été établies. Les propriétés peuvent être attachées aux éléments architecturaux des modèles de composants et leurs valeurs peuvent être comparées et raffinées durant le développement. En particulier, le fait d’avoir des valeurs multiples avec leur contexte d’évaluation permet de comparer des valeurs provenant de différentes sources. Les concepts proposés ont été illustrés au travers d’exemples représentatifs de systèmes. / The continuously increasing complexity of embedded systems is a major issue for their development, which, in addition, must also consider specific extra-functional requirements and constraints, such as limited and shared resources, distribution, timing, and dependability. Thus, embedded systems call for development solutions that can efficiently and predictably cope with these issues. Component-based software engineering is a proven paradigm to handle complexity. Yet, for efficiently managing extra-functional properties, a component model needs to have dedicated mechanisms that provide a suitable support for their management. The objective of this thesis is to build this support. We have performed a systematic analysis of existing component models and identified challenges of applying a component-based approach to embedded system development. Based on these challenges we have advanced the current state-of-the-art by developing a new component model, called ProCom, that accommodates the specifics of embedded systems through its well-defined execution semantics and layered structure. Centered around ProCom, we have also developed PRIDE, the ProCom Integrated Development Environment. PRIDE supports the development from early specification to synthesis and deployment, providing the means to aggregate various analysis and verification tools. The main contribution of the thesis is in the design and implementation of an extra-functional property management framework that enables to seamlessly specify, manage and integrate multi-valued context-aware extra-functional properties of component-based embedded systems. Properties can be attached to architectural elements of component models and their values can be compared and refined during the development process. In particular, having multiple context-aware values allows values from different sources to be compared. The proposed concepts have been demonstrated on several representative example systems.

Safety-critical applications employed in automotive, avionics and aerospace domains are placed under strict demands for performance, power efficiency and fault tolerance. Development of system hardware and software satisfying all criteria is challenging and time-consuming. System co-design based on specifications and desired high-performance requirements, is one solution to this problem, however, it remains a largely unexplored territory. Currently at KTH Royal Institute of Technology, a co-design framework in relation to theoretical system design models is being researched with the objective to move the embedded system design to a higher abstraction level. Presently, it focuses on correct-by-construction design of low power and reliable safety-critical systems. This thesis intends to assess the accuracy of this framework in comparison to conventional design approaches. The accuracy is evaluated empirically in terms of extra functional requirements - average total power consumption and Mean Time Between Failure (MTBF). A simple payload Central Direct Memory Access (CDMA) application is integrated with Xilinx Soft Error Mitigation (SEM) IP Core and source of system failure is a Single Event Upset (SEU) which occurs due to ionizing radiations. Measurements obtained from this reference system are compared to results determined theoretically from model related equations for the same system. Comparison of measured MTBF values with theoretical estimations shows that measured ones are higher by an average huge difference of 324.63%. Similarly for power consumption, measurements were found to be higher than estimated ones by 0.4465 Watts. In conclusion, it can be said that theoretical model design framework is not accurate and models must somehow take into account implementation dependent factors. Nevertheless, this case study provided a good insight and pathways for enhancements and optimizations to turn this reference into a dependable platform. Finally, future work required for desirable experiment system improvements are identified. / Säkerhetskritiska applikationer som används inom fordons-, flyg- och flygindustrin ställs strikta krav på prestanda, energieffektivitet och feltolerans. Utveckling av systemhårdvara och mjukvara som uppfyller alla kriterier är utmanande och tidskrävande. Systemdesign baserad på specifikationer och önskade högpresterande krav är en lösning på detta problem, men det är fortfarande ett i stort sett outforskat område. För närvarande vid KTH Royal Institute of Technology undersöks ett ramverk för samdesign i relation till teoretiska systemdesignmodeller undersöks med målet att flytta den inbyggda systemdesignen till en högre abstraktionsnivå. Nuvarande, den fokuserar på korrekt konstruktion av låg effekt och pålitliga säkerhetskritiska system. Denna avhandling avser att bedöma riktigheten i detta ramverk i jämförelse med konventionella designmetoder. Noggrannheten utvärderas empiriskt när det gäller extra funktionskrav - genomsnittlig total strömförbrukning och medeltid mellan misslyckande (MTBF). En enkel nyttolast central direktminnesåtkomst (CDMA) applikation är integrerad med Xilinx begränsning av en händelse (SEM) IP kärnan och källan till systemfel är en singelhändelse upprörd (SEU) som uppstår på grund av joniserande strålning. Mätningar erhållna från detta referenssystem jämförs med resultat som bestämts teoretiskt från modellrelaterade ekvationer för samma system. Jämförelse av uppmätta MTBF -värden med teoretiska uppskattningar visar att uppmätta värden är högre med en genomsnittlig enorm skillnad på 324,63%. På samma sätt för strömförbrukning befanns mätningarna vara högre än beräknade med 0,4465 Watt. Sammanfattningsvis kan man säga att det teoretiska ramverket för modelldesign inte är korrekt och att modellerna på något sätt måste ta hänsyn till implementeringsberoende faktorer. Ändå gav denna fallstudie en bra insikt och vägar för förbättringar och optimeringar för att göra denna referens till en pålitlig plattform. Slutligen identifieras framtida arbete som krävs för önskvärda experimentsystemförbättringar.