Modelling Event-Based Interactions in Component-Based Architectures for Quantitative System Evaluation

This dissertation thesis presents an approach enabling the modelling and quality-of-service prediction of event-based systems at the architecture-level. Applying a two-step model refinement transformation, the approach integrates platform-specific performance influences of the underlying middleware while enabling the use of different existing analytical and simulation-based prediction techniques

Modelling Event-Based Interactions in Component-Based Architectures for Quantitative System Evaluation

This dissertation thesis presents an approach enabling the modelling and quality-of-service prediction of event-based systems at the architecture-level. Applying a two-step model refinement transformation, the approach integrates platform-specific performance influences of the underlying middleware while enabling the use of different existing analytical and simulation-based prediction techniques

Modeling and Simulation of Message-Driven Self-Adaptive Systems

Dynamische, sich selbst rekonfigurierende Systeme nutzen Nachrichtenwarteschlangen als gängige Methode zum Erreichen von Entkopplung zwischen Sendern und Empfängern. Das Vorhersagen der Qualität von Systemen zur Entwurfszeit ist wesentlich, da Änderungen in späteren Phasen der Entwicklung sehr viel aufwändiger und teurer sind. Momentan gibt es keine Methode, Nachrichtenwarteschlangen auf architekturellem Level darzustellen und deren Qualitätseinfluss auf Systeme vorherzusagen. Existierende Ansätze modellieren Warteschlangen nicht explizit sondern abstrahieren sie. Warteschlangeneffekte sowie Details der Nachrichten-Infrastruktur wie zum Beispiel Flusskontrolle werden nicht beachtet. Diese Arbeit schlägt ein Meta-Modell vor, das eine solche Repräsentation ermöglicht, und eine Simulations-Schnittstelle zwischen einer Simulation einer komponentenbasierten Architekturbeschreibungssprache und einer Nachrichtenaustausch-Simulation. Das Meta-Modell wurde als Erweiterung des Palladio Komponentenmodells realisiert. Die Schnittstelle wurde implementiert für den Palladio-Simulator SimuLizar und eine von RabbitMQ inspirierte Simulation, die dem AMQP 0.9.1 Protokoll folgt. Dies ermöglicht architekturelle Repräsentation von Nachrichtenaustausch und das Vorhersagen von Qualitätsattributen von nachrichtengetriebenen, selbst-adaptiven Systemen. Die Evaluation anhand einer Fallstudie zeigt die Anwendbarkeit des Ansatzes und seine Vorhersagegenauigkeit für Punkt-zu-Punkt-Kommunikation. Außerdem konnten andere qualitätsbezogene Metriken, wie etwa Nachrichtenwarteschlangenlänge, Ein- und Ausgangsraten von Nachrichtenwarteschlangen, sowie Speicherverbrauch korrekt vorhergesagt werden. Das ermöglicht tiefere Einsichten in die Qualität eines Systems. Wir argumentieren weiterhin, dass der Ansatz in dieser Arbeit selbst-adaptive nachrichtengetriebene Systeme, die sich basierend auf verschiedenen Metriken rekonfigurieren, simulieren kann

Architecture-based Evolution of Dependable Software-intensive Systems

This cumulative habilitation thesis, proposes concepts for (i) modelling and analysing dependability based on architectural models of software-intensive systems early in development, (ii) decomposition and composition of modelling languages and analysis techniques to enable more flexibility in evolution, and (iii) bridging the divergent levels of abstraction between data of the operation phase, architectural models and source code of the development phase

Weighted Statistical Testing based on Active Learning and Formal Verification Techniques for Software Reliability Assessment

This work developed an automatic approach for the assessment of software reliability which is both theoretical sound and practical. The developed approach extends and combines theoretical sound approaches in a novel manner to systematically reduce the overhead of reliability assessment

An Architecture-based Approach for Change Impact Analysis of Software-intensive Systems

A main property of software-intensive technical systems is sustainability. Sustainable systems need to change continuously. A change to a system element can result in further changes to other system elements. If these elements originate from different domains, the change can also propagate between several domains. This book presents an architecture-based approach to change propagation analysis of software-intensive technical systems that considers heterogeneous elements from different domain

Deriving Goal-oriented Performance Models by Systematic Experimentation

Performance modelling can require substantial effort when creating and maintaining performance models for software systems that are based on existing software. Therefore, this thesis addresses the challenge of performance prediction in such scenarios. It proposes a novel goal-oriented method for experimental, measurement-based performance modelling. We validated the approach in a number of case studies including standard industry benchmarks as well as a real development scenario at SAP

Efficiently Conducting Quality-of-Service Analyses by Templating Architectural Knowledge

Previously, software architects were unable to effectively and efficiently apply reusable knowledge (e.g., architectural styles and patterns) to architectural analyses. This work tackles this problem with a novel method to create and apply templates for reusable knowledge. These templates capture reusable knowledge formally and can efficiently be integrated in architectural analyses

Consistent View-Based Management of Variability in Space and Time

Developing variable systems faces many challenges. Dependencies between interrelated artifacts within a product variant, such as code or diagrams, across product variants and across their revisions quickly lead to inconsistencies during evolution. This work provides a unification of common concepts and operations for variability management, identifies variability-related inconsistencies and presents an approach for view-based consistency preservation of variable systems