Adaptivity engineering : Modeling and quality assurance for self-adaptive software systems

Moderne Softwareentwicklung nutzt Techniken der Selbstadaptation, um Wartung von Softwaresystemen zu automatisieren und diese somit flexibler und robuster zu gestalten. Allerdings führt die Einführung solcher Techniken zu größeren und komplizierten Softwareentwürfen. Die Konsequenz sind Fehler im Entwurf. In der Literatur werden konstruktive Methoden wie MDE oder Patterns und analytische Methoden wie Testen oder Model Checking vorgeschlagen, um das Komplexitätsproblem zu verringern. Allerdings werden die Techniken der Selbstadaption von solchen Methoden bisher noch wenig unterstützt, d.h. dass es wenige integrierte Ansätze für die explizite Modellierung und Qualitätssicherung von Selbstadaptation gibt. In dieser Arbeit schlagen wir einen integrierten Modellierungs- und Qualitätssicherungsansatz für den Entwurf selbstadaptiver Softwaresysteme vor. Es werden sowohl konstruktive Methoden (z.B. Sprachen) als auch analytische Methoden (z.B. Model Checking) für die Unterstützung der Entwicklung solcher Systeme vorgeschlagen. Beide Typen von Methoden sind in Standardtechniken und Werkzeuge integriert. Im Ergebnis wird der Entwickler in der Modellierung selbstadaptiver Softwaresysteme durch den Einsatz von adaptionsspezifischen Sprachen unterstützt. Durch die dazu passenden Qualitätssicherungsverfahren erhält der Entwickler unmittelbare Rückmeldung über die Qualität seiner Modelle. Somit wird die Entwicklung selbstadaptiver Systeme bereits in frühen Phasen des Entwicklungsprozesses unterstützt, Entwurfsfehler werden vermieden und somit bessere Software gebaut.Modern software engineering introduces self-adaptivity features to perform automatic maintenance and make software systems more flexible and resilient. Unfortunately, introducing the additional self-adaptivity features makes software design bloated and complicated. As a consequence, software design models are often prone to errors. The literature proposes constructive approaches such as MDE, patterns, etc. as well as analytical approaches such as testing or model checking to solve the problem of complexity in general. However, there is no sufficient adaptivity-specific support throughout the engineering process, i.e. no approaches that support the creation of self-adaptivity specification models and their quality assurance. In this thesis, we will propose an integrated modeling and quality assurance environment for designing self-adaptive software systems. Therefore, we will propose constructive methods (e.g., languages) and analytical methods (e.g., model-checking) to support the engineering of these systems. Both types of methods are integrated into standard software engineering techniques and tools. As a result, the designer is supported in modeling self-adaptive software systems using concern-specific languages and receives immediate feedback about the quality of his models. This way, software engineering for self-adaptive systems is getting supported starting at the early design phase leading to less errors produced, and thus, to better software, overall.Tag der Verteidigung: 26.09.2013Paderborn, Univ., Diss., 201

Timing Architecture for ESS

Programa Oficial de Doutoramento en Investigación en Tecnoloxías da Información. 5023V01[Resumo] O sistema de temporización é unha compoñente fundamental para o control e sincronización de instalacións industriais e científicas, coma aceleradores de partículas. Nesta tese traballamos na especificación e desenvolvemento do sistema de temporización para a European Spallation Source (ESS), a maior fonte de neutróns actualmente en construción. Abordamos este tra­ ballo a dous niveis: a especificación do sistema de temporización, e a imple­ mentación física de sistemas de control empregando circuítos reconfigurables. Con respecto á especificación do sistema de temporización, deseñamos e implementamos a configuración do protocolo de temporización para cumprir cos requirimentos do ESS e ideamos un modo de operación e unha aplicación para a configuración e control do sistema de temporización. Tamén presentamos unha ferramenta e unha metodoloxía para imple­ mentar sistemas de control empregando FPGAs, coma os nodos do sistema de temporización. ámbalas <lúas están baseadas en statecharts, unha repre­ sentación gráfica de sistemas que expande o concepto de máquinas de estados finitos, orientada a sistemas que necesitan ser reconfigurados rápidamente en múltiples localizacións minimizando a posibilidade de erros. A ferramenta crea automaticamente código VHDL sintetizable a partir do statechart do sistema. A metodoloxía explica o procedemento para implementar o state­ chart como unha arquitectura microprogramada en FPGAs.[Resumen] El sistema de temporización es un componente fundamental para el control y sincronización de instalaciones industriales y científicas, como aceleradores e partículas. En esta tesis trabajamos en la especificación y desarrollo el sistema de temporización para la European Spallation Source (ESS), la mayor fuente de neutrones actualmente en construcción. Abordamos este trabajo en dos niveles: la especificación del sistema de temporización, y la mplementación física de sistemas de control empleando circuitos reconfig­ rables. Con respecto a la especificación del sistema de temporización, diseñamos e implementamos la configuración del protocolo de temporización para cumplir on los requisitos de ESS e ideamos un modo de operación y una aplicación ara la configuración y control del sistema de temporización. También presentamos una herramienta y una metodología para imple­ entar sistemas de control empleando FPGAs, como los nodos del sistema e temporización. Ambas están basadas en statecharts) una representación gráfica de sistemas que expande el concepto de máquinas de estados fini­ os, orientada a sistemas que necesitan ser reconfigurados rápidamente en últiples localizaciones minimizando la posibilidad de errores. La her­ramienta crea automáticamente código VHDL sintetizable a partir del state­chart del sistema. La metodología explica el procedimiento para implemen­tar el statechart como una arquitectura microprogramada en FPGAs.[Abstract] The timing system is a key component for the control and synchronization of industrial and scientific facilities, such as particle accelerators. In this thesis we tackle the specification and development of the timing system for the European Spallation Source (ESS), the largest neutron source currently in construction. We approach this work at two levels: the specification of the timing system and the physical implementation of control systems using reconfigurable hardware. Regarding the specification of the timing system, we designed and imple­ mented the configuration of the timing protocol to fulfil the requirements of ESS and devised an operation mode andan application for the configuration and control of the timing system. We also present one too! and one methodology to implement control systems using FPGAs, such as the nodes of the timing system. Both are based on statecharts, a graphical representation of systems that expand the concepts of Finite State Machines, targeted at systems that need to be re­ configured quickly in multiple locations minimizing the chance of errors. The too! automatically creates synthesizable VHDL code from a statechart of the system. The methodology explains the procedure to implement the statechart as a microprogrammed architecture in FPGAs

Fundamental Approaches to Software Engineering

computer software maintenance; computer software selection and evaluation; formal logic; formal methods; formal specification; programming languages; semantics; software engineering; specifications; verificatio

User-centric product derivation in software product lines

Software Product Line (SPL) engineering aims at achieving efficient development of software products in a specific domain. New products are obtained via a process which entails creating a new configuration specifying the desired product’s features. This configuration must necessarily conform to a variability model, that describes the scope of the SPL, or else it is not viable. To ensure this, configuration tools are used that do not allow invalid configurations to be expressed. A different concern, however, is making sure that a product addresses the stakeholders’ needs as best as possible. The stakeholders may not be experts on the domain, so they may have unrealistic expectations. Also, the scope of the SPL is determined not only by the domain but also by limitations of the development platforms. It is therefore possible that the desired set of features goes beyond what is possible to currently create with the SPL. This means that configuration tools should provide support not only for creating valid products, but also for improving satisfaction of user concerns. We address this goal by providing a user-centric configuration process that offers suggestions during the configuration process, based on the use of soft constraints, and identifying and explaining potential conflicts that may arise. Suggestions help mitigating stakeholder uncertainty and poor domain knowledge, by helping them address well known and desirable domain-related concerns. On the other hand, automated conflict identification and explanation helps the stakeholders to understand the trade-offs required for realizing their vision, allowing informed resolution of conflicts. Additionally, we propose a prototype-based approach to configuration, that addresses the order-dependency issues by allowing the complete (or partial) specification of the features in a single step. A subsequent resolution process will then identify possible repairs, or trade-offs, that may be required for viabilization

Feature Model Synthesis

Variability provides the ability to adapt and customize a software system's artifacts for a particular context or circumstance. Variability enables code reuse, but its mechanisms are often tangled within a software artifact or scattered over multiple artifacts. This makes the system harder to maintain for developers, and harder to understand for users that configure the software. Feature models provide a centralized source for describing the variability in a software system. A feature model consists of a hierarchy of features—the common and variable system characteristics—with constraints between features. Constructing a feature model, however, is a arduous and time-consuming manual process. We developed two techniques for feature model synthesis. The first, Feature-Graph-Extraction, is an automated algorithm for extracting a feature graph from a propositional formula in either conjunctive normal form (CNF), or disjunctive normal form (DNF). A feature graph describes all feature diagrams that are complete with respect to the input. We evaluated our algorithms against related synthesis algorithms and found that our CNF variant was significantly faster than the previous comparable technique, and the DNF algorithm performed similarly to a comparable, but newer technique, with the exception of several models where our algorithm was faster. The second, Feature-Tree-Synthesis, is a semi-automated technique for building a feature model given a feature graph. This technique uses both logical constraints and text to address the most challenging part of feature model synthesis—constructing the feature hierarchy—by ranking potential parents of a feature with a textual similarity heuristic. We found that the procedure effectively reduced a modeler's choices from thousands, to five or less when synthesizing the Linux and eCos variability models. Our third contribution is the analysis of Kconfig—a language similar to feature modeling used to specify the variability model of the Linux kernel. While large feature models are reportedly used in industry, these models have not been available to the research community for benchmarking feature model analysis and synthesis techniques. We compare Kconfig to feature modeling, reverse engineer formal semantics, and translate 12 open-source Kconfig models—including the Linux model with over 6000 features—to propositional logic

Pushing the Boundaries of Spacecraft Autonomy and Resilience with a Custom Software Framework and Onboard Digital Twin

This research addresses the high CubeSat mission failure rates caused by inadequate software and overreliance on ground control. By applying a reliable design methodology to flight software development and developing an onboard digital twin platform with fault prediction capabilities, this study provides a solution to increase satellite resilience and autonomy, thus reducing the risk of mission failure. These findings have implications for spacecraft of all sizes, paving the way for more resilient space missions

Proceedings, MSVSCC 2012

Proceedings of the 6th Annual Modeling, Simulation & Visualization Student Capstone Conference held on April 19, 2012 at VMASC in Suffolk, Virginia