Qos-Based Web Service Discovery And Selection Using Machine Learning

In service computing, the same target functions can be achieved by multiple Web services from different providers. Due to the functional similarities, the client needs to consider the non-functional criteria. However, Quality of Service provided by the developer suffers from scarcity and lack of reliability. In addition, the reputation of the service providers is an important factor, especially those with little experience, to select a service. Most of the previous studies were focused on the user's feedbacks for justifying the selection. Unfortunately, not all the users provide the feedback unless they had extremely good or bad experience with the service. In this vision paper, we propose a novel architecture for the web service discovery and selection. The core component is a machine learning based methodology to predict the QoS properties using source code metrics. The credibility value and previous usage count are used to determine the reputation of the service.Comment: 8 Pages, 3 Figure

Resilience, Reliability, and Recoverability (3Rs)

Recent natural and human-made disasters, mortgage derivatives crises, and the need for stable systems in different areas have renewed interest in the concept of resilience, especially as it relates to complex industrial systems with mechanical failures. This concept in the engineering systems (infrastructure) domain could be interpreted as the probability that system conditions exceed an irrevocable tipping point. But the probability in this subject covers the different areas that different approaches and indicators can evaluate. In this context, reliability engineering is used the reliability (uptime) and recoverability (downtime) indicators (or performance indicators) as the most useful probabilistic tools for performance measurement. Therefore, our research penalty area is the resilience concept in combination with reliability and recoverability. It must be said that the resilience evaluators must be considering a diversity of knowledge sources. In this thesis, the literature review points to several important implications for understanding and applying resilience in the engineering area and The Arctic condition. Indeed, we try to understand the application and interaction of different performance-based resilience concepts. In this way, a collection of the most popular performance-based resilience analysis methods with an engineering perspective is added as a state-of-the-art review. The performance indicators studies reveal that operational conditions significantly affect the components, industry activities, and infrastructures performance in various ways. These influential factors (or heterogeneity) can broadly be studied into two groups: observable and unobservable risk factors in probability analysis of system performance. The covariate-based models (regression), such as proportional hazard models (PHM), and their extent are the most popular methods for quantifying observable and unobservable risk factors. The report is organized as follows: After a brief introduction of resilience, chapters 2,3 priorly provide a comprehensive statistical overview of the reliability and recoverability domain research by using large scientific databases such as Scopus and Web of Science. As the first subsection, a detailed review of publications in the reliability and recoverability assessment of the engineering systems in recent years (since 2015) is provided. The second subsection of these chapters focuses on research done in the Arctic region. The last subsection presents covariate-based reliability and recoverability models. Finally, in chapter 4, the first part presents the concept and definitions of resilience. The literature reviews four main perspectives: resilience in engineering systems, resilience in the Arctic area, the integration of “Resilience, Reliability, and Recoverability (3Rs)”, and performance-based resilience models

Exploring and categorizing maintainability assurance research for service and microservice-based systems

Im Laufe des Softwarelebenszyklus eines Programms innerhalb einer sich ständig wechselnden Softwareumgebung ist es wahrscheinlich, dass dieses Programm regelmäßig gewartet werden muss. Wartungen kosten Geld und somit ist es wichtig, dass ebensolche Wartungen effizient und effektiv durchgeführt werden können. Im Laufe der Geschichte der Softwareentwicklung traten unter anderem zwei Architekturmuster hervor: Serviceorientierte Architektur und Microservices. Da diese Architekturmuster ein hohes Maß an Wartbarkeit versprechen, wurden viele Altsysteme hin zu diesen modernen Architekturen migriert. Es kann fatale Folgen für Unternehmen haben, wenn Änderungen an einem System nicht schnell, risikofrei und fehlerfrei umgesetzt werden können. Es wurden bereits viele Forschungsarbeiten bezogen auf die Wartbarkeit von serviceorientierter Architektur publiziert. Systeme basierend auf Microservices fanden jedoch, bezogen auf Wartbarkeitssicherung, nicht viel Beachtung. Sämtliche Forschungsarbeiten befinden sich verteilt auf viele Literaturdatenbanken, wodurch ein umfassender Überblick erschwert wird. Um einen solchen Überblick bereitzustellen, führten wir im Rahmen dieser Bachelorarbeit eine systematische Literaturstudie durch, die sich mit der Wartbarkeitssicherung von serviceorienter Architektur und Systemen basierend auf Microservices beschäftigt. Zur Durchführung dieser systematischen Literaturstudie entwickelten wir eine Reihe von relevanten Forschungsfragen sowie ein striktes Forschungsprotokoll. Aufbauend auf diesem Protokoll sammelten wir insgesamt 223 Forschungsarbeiten von verschiedenen Herausgebern. Diese Arbeiten wurden bezüglich ihres Inhalts zuerst in drei Gruppen von Kategorien unterteilt (architektonisch, thematisch und methodisch). Danach wurden die jeweils relevantesten Forschungsrichtungen aus jeder thematischen Kategorie herausgearbeitet und vorgestellt. Zum Abschluss wurden deutliche Unterschiede der in den Forschungsarbeiten präsentierten Inhalte in Bezug auf serviceorientierte Architektur und Microservice-basierte Systeme herausgearbeitet und dargestellt. Unsere Ergebnisse zeigten eine deutliche Unterrepräsentation von Forschungsarbeiten zur Wartbarkeitssicherung für Microservice-basierte Systeme. Während der Untersuchung der Kategorien konnten wir diverse Forschungsrichtungen innerhalb dieser feststellen. Ein Beispiel hierfür ist die Forschungsrichtung "change impact in business processes" in der Kategorie "Change Impact and Scenarios". Abschließend konnten wir einige Unterschiede bezogen auf die gesammelten Forschungsarbeiten zwischen Systemen basierend auf einer serviceorientierten Architektur und Systemen basierend auf Microservices feststellen. Ein solcher Unterschied kann zum Beispiel in der Kategorie "Antipatterns and Bad Smells" gefunden werden. Im Vergleich zu Forschungsarbeiten, welche sich auf serviceorientierte Architektur beziehen, beinhalten Forschungsarbeiten im Zusammenhang mit Systemen auf Basis von Microservices nur grundlegende Informationen zu Antipatterns, jedoch keine Herangehensweisen, um diese zu erkennen. Aufgrund unserer Ergebnisse schlagen wir einen stärkeren Fokus auf Forschung zur Wartbarkeitssicherung in Microservice-basierten Systemen vor. Mögliche zukünftige Forschungsarbeiten könnten überprüfen, ob Herangehensweisen zur Wartbarkeitssicherung von serviceorientierter Architektur auch bei Microservices anwendbar sind. Darüber hinaus schlagen wir die Durchführung von systematischen Literaturstudien vor, welche Themen wie "runtime adaptation", "testing" und "legacy migration" untersuchen, da diese Themen in unserer Literaturstudie ausgeschlossen wurden.It is very likely that software running in an everchanging environment needs to evolve at multiple points during its lifecycle. Because maintenance costs money, it is important for such tasks to be as effective and efficient as possible. During the history of software development service- and microservice-based architectures have emerged among other architectures. Since these architectures promise to provide a high maintainability, many legacy systems are or were migrated towards a service- or microservice-based architecture. In order to keep such systems running, maintenance is inevitable. While a lot of research has been published regarding maintainability assurance for service-based systems, microservice-based systems have not gotten a lot of attention. All published research is spread across several scientific databases which makes it difficult to get an extensive overview of existing work. In order to provide such overview of maintainability assurance regarding service- and microservice-based systems, we conducted a systematic literature review. To support our literature review, we developed a set of meaningful research questions and a rigid research protocol. Based on our protocol we collected a set of 223 different papers. These papers were first categorized into a threefold set of categories (architectural, thematical and methodical). After that, the most relevant research directions from each thematical category were extracted and presented. Lastly, we extracted and presented notable differences between approaches relating to service-oriented architecture or microservice-based systems. Our findings show a clear underrepresentation of maintainability assurance approaches suitable for microservice-based systems. We further discovered that regarding our formed categories, we could find several research directions such as change impact in business processes in "Change Impact and Scenarios". In the end, we could identify some differences between service- and microservice-based systems concerning approaches we retrieved in this thesis. A difference, for example was that in comparison with papers related to service-oriented architecture in "Antipatterns and Bad Smells", microservices related papers only contained basic information on antipatterns, but no approaches to detect them. Due to our findings we suggest a higher participation in research regarding maintainability assurance for microservice-based systems. Possible future work in this area could include further research on the applicability of service-oriented maintainability assurance approaches or techniques in microservice-based systems. Furthermore, future researchers could conduct follow-up literature reviews and investigate topics such as runtime adaptation, testing and legacy migration, since we excluded such topics from this thesis