Papers by Wilhelm Hasselbring
Information and Software Technology, 2017
Context: The number of software applications deployed in organizations is constantly increasing. ... more Context: The number of software applications deployed in organizations is constantly increasing. Those applications – often several hundreds – form large software landscapes. Objective: The comprehension of such landscapes and their applications is often impeded by, for instance , architectural erosion, personnel turnover, or changing requirements. Therefore, an efficient and effective way to comprehend such software landscapes is required. Method: In our ExplorViz visualization, we introduce hierarchical abstractions aiming at solving system comprehension tasks fast and accurately for large software landscapes. Besides hierarchical visualiza-tion on the landscape level, ExplorViz provides multi-level visualization from the landscape to the level of individual applications. The 3D application-level visualization is empirically evaluated with a comparison to the Extravis approach, with physical models and in virtual reality. To evaluate ExplorViz, we conducted four controlled experiments. We provide packages containing all our experimental data to facilitate the verifiability, reproducibility, and further extensibility of our results. Results: We observed a statistical significant increase in task correctness of the hierarchical visualiza-tion compared to the flat visualization. The time spent did not show any significant differences. For the comparison with Extravis, we observed that solving program comprehension tasks using ExplorViz leads to a significant increase in correctness and in less or similar time spent. The physical models improved the team-based program comprehension process for specific tasks by initiating gesture-based interaction, but not for all tasks. The participants of our virtual reality experiment with ExplorViz rated the realized gestures for translation, rotation, and selection as highly usable. However, our zooming gesture was less favored. Conclusion: The results backup our claim that our hierarchical and multi-level approach enhances the current state of the art in landscape and application visualization for better software system comprehension , including new forms of interaction with physical models and virtual reality.
2017 IEEE International Conference on Software Architecture Workshops (ICSAW), 2017
Microservice architectures provide small services that may be deployed and scaled independently o... more Microservice architectures provide small services that may be deployed and scaled independently of each other, and may employ different middleware stacks for their implementation. Microservice architectures intend to overcome the shortcomings of monolithic architectures where all of the application's logic and data are managed in one deployable unit. We present how the properties of microservice architectures facilitate scalability, agility and reliability at otto.de, which is one of the biggest European e-commerce platforms. In particular, we discuss vertical decomposition into self contained systems and appropriate granularity of microservices as well as coupling, integration, scalability and monitoring of microservices at otto.de. While increasing agility to more than 500 live deployments per week, high reliability is achieved by means of automated quality assurance with continuous integration and deployment.
DELOS Research …, Jan 1, 2005
Digital Libraries (DLs) in eHealth are composed of electronic artefacts that are generated and ow... more Digital Libraries (DLs) in eHealth are composed of electronic artefacts that are generated and owned by different healthcare providers. A major characteristic of eHealth DLs is that information is under the control of the organisation where data has been produced. The electronic health record (EHR) of patients therefore consists of a set of distributed artefacts and cannot be materialised for organisational reasons. Rather, the EHR is a virtual entity. The virtual integration of an EHR is done by encompassing services provided by specialised application systems into processes. This paper reports, from an application point of view, on national and European attempts to standardise electronic health EHR. From a technical perspective, the paper addresses how services can be made available in a distributed way, how distributed P2P infrastructures for the management of EHRs can be evaluated, and how novel content-based access can be provided for multimedia EHRs.
Insk, 2006
Software hat sich zu einem zentralen Werkstoff des Informationszeitalters entwickelt. Innovative ... more Software hat sich zu einem zentralen Werkstoff des Informationszeitalters entwickelt. Innovative Produkte und Dienstleistungen sind ohne zuverlässige Software nicht mehr denkbar. Dementsprechend hängt die Wettbewerbsfähigkeit der deutschen Wirtschaft entscheidend von der Fähigkeit ab, Software-intensive Produkte und Dienstleistungen mit höchster Qualität schnell und kostengünstig zu erstellen. Software Engineering (abgekürzt SE, deutsch Softwaretechnik) auf Weltniveau ist die Voraussetzung dafür, dass Deutschland seine führende Stellung im Ingenieurbereich (z.B. Export-Weltmeister im Maschinenbau) halten und ausbauen bzw. eine entsprechende Position in neuen Sparten (z.B. e-Health) aufbauen kann. Die Bedeutung von Software Engineering hat sich verstärkt und wird weiter wachsen. Während Software in der Vergangenheit eine weitgehend isolierte Komponente großer komplexer Systeme war, so wird sie in der Zukunft integrierter -in vielen Fällen sogar dominierender -Teil großer komplexer Systeme sein. In der Automobilindustrie wird dieser Trend bereits heute deutlich sichtbar. Die erforderliche Integration von Mechanik, Elektronik und Software und die Vermeidung unerwünschter Wechselwirkungen kann nur durch die frühzeitige Integration der Modellierungskompetenzen des Software Engineering in den Entwicklungsprozess beherrscht werden. Diese neue Positionierung von Software Engineering als systemische Disziplin erfordert eine neue Ausrichtung in den drei Bereichen Forschung, Lehre und Technologietransfer. Dieses Manifest stellt Forderungen inhaltlicher und organisatorischer Art für Forschung, Lehre und Technologietransfer auf, deren Erfüllung der wirtschaftlichen Bedeutung von Software und Software Engineering Rechnung tragen soll. Es ist die auf sorgfältige Untersuchungen abgestützte Überzeugung der Unterzeichner, dass verstärkte Anstrengungen in allen drei Bereichen notwendig sind, um den Herausforderungen [BJN+06] M. Broy, M.
ACM SIGMOD Record, 1999
After the successful rst International Workshop on Engineering Federated Database Systems EFDBS'9... more After the successful rst International Workshop on Engineering Federated Database Systems EFDBS'97 in Barcelona in June 1997 CEH + 97 , the goal of this second workshop was to bring together researchers and practitioners interested in various issues in the development of federated information systems, whereby the scope has been extended to cover database and non-database information sources the change from EFDBS to EFIS re ects this. This report provides details of the workshop content and the conclusions reached in the nal discussion.
Die Entwicklung elektronischer Stellwerke für den Bahnbetrieb ist ein aufwändiges Unterfangen, we... more Die Entwicklung elektronischer Stellwerke für den Bahnbetrieb ist ein aufwändiges Unterfangen, welches sich besonders für die zahlreichen Nebenstrecken und andere kleinere Bahnanlagen häufig als unrentabel erweist. Um in Zukunft einerseits mehr Verkehr auf die Schiene zu bringen und zudem die Kosten für den Betrieb der Infrastruktur zu senken, müssen die Hardware-Komponenten günstiger werden, aber auch die Entwicklung der darauf laufenden Software produktiver erfolgen, ohne Abstriche bei der Sicherheit zu machen.
Software Engineering, 2008
Wirberichten über unsere Erfahrungen aus drei unterschiedlichen Migrationsprojekten, um daraus ve... more Wirberichten über unsere Erfahrungen aus drei unterschiedlichen Migrationsprojekten, um daraus verallgemeinerte Muster abzuleiten.
Pahl Claus and Boskovic Marko and Barrett Ronan and Hasselbring Wilhelm Quality Aware Model Driven Service Engineering in Rech J and Bunse C Model Driven Software Development Integrating Quality Assurance Information Science Reference Igi Global Pp 400 430 Isbn 978 160566006 6, Oct 1, 2008
Service engineering and service-oriented architecture as an integration and platform technology i... more Service engineering and service-oriented architecture as an integration and platform technology is a recent approach to software systems integration. Quality aspects ranging from interoperability to maintainability to performance are of central importance for the integration of heterogeneous, distributed service-based systems. Architecture models can substantially influence quality attributes of the implemented software systems. Besides the benefits of explicit architectures on maintainability and reuse, architectural constraints such as styles, reference architectures and architectural patterns can influence observable software properties such as performance. Empirical performance evaluation is a process of measuring and evaluating the performance of implemented software. We present an approach for addressing the quality of services and service-based systems at the model-level in the context of model-driven service engineering. The focus on architecture-level models is a consequence of the black-box character of services.
Ehmke Nils Christian Wulf Christian and Hasselbring Wilhelm the Kieker Analysis Framework Kieker S Webgui Christian Albrechts Universitat Zu Kiel, Nov 7, 2014
In Kontrollzentren für Telefon-, Ve rkehrs-oder Energieversorgungsnetzen werden Leitstände verwen... more In Kontrollzentren für Telefon-, Ve rkehrs-oder Energieversorgungsnetzen werden Leitstände verwendet, um dem Betriebspersonal einen schnellen Überblick über die Netzarchitektur und deren gegenwärtige Eigenschaften (z.B. Auslastung) zu bieten. Leitstände sind ein grundlegender Bestandteil vonK ontrollzentren z.B. für Energieversorgungsnetze. Für Softwaresysteme sind solche Überwachungs-und Steuerungssysteme bislang wenig verbreitet. Leitstände können bei der Systemüberwachung und dem Erkennen und Beheben vonS törungen helfen, da Betriebsdaten im Zusammenhang überblickt werden können. Wircharakterisieren Software-Betriebs-Leitstände mit Hilfe einer Taxonomie vonSoftware-Leitständen und beschreiben Anforderungen an solche Leitstände, beispielhaft für JavaEE-basierte Systeme. * Diese Arbeit wurde gefördert durch die Deutsche Forschungsgemeinschaft, GRK 1076/1.
Pahl Claus and Boskovic Marko and Hasselbring Wilhelm Model Driven Performance Evaluation For Service Engineering in Gschwind Thomas and Pautasso Cesare Emerging Web Services Technology Birkhaeuser Computer Science Ii Springer Birkhaeuser Pp 171 185 Isbn 978 3 7643 8863 9, 2008
Service engineering and service-oriented architecture as an integration and platform technology i... more Service engineering and service-oriented architecture as an integration and platform technology is a recent approach to software systems integration. Software quality aspects such as performance are of central importance for the integration of heterogeneous, distributed service-based systems. Empirical performance evaluation is a process of measuring and calculating performance metrics of the implemented software. We present an approach for the empirical, model-based performance evaluation of services and service compositions in the context of model-driven service engineering. Temporal databases theory is utilised for the empirical performance evaluation of model-driven developed service systems.
Model-based measurement techniques are relevant in the field of software analysis. Several meta m... more Model-based measurement techniques are relevant in the field of software analysis. Several meta models for the specification of quantitative measures have been proposed. However, they often focus either on static or dynamic aspects of a software system. Nevertheless, considering reengineering activities often both dimensions reveal valuable complementary insights. Existing meta models are also frequently bound to specific modeling languages, redefine underlying concepts for any new meta model, or provide only limited tool support for the automated computation of measurements from modeled measures.
Gi Jahrestagung, 2006
Lernmanagementsysteme unterstützen Lehrende und Lernende bei der Organisation des Lehrens und Ler... more Lernmanagementsysteme unterstützen Lehrende und Lernende bei der Organisation des Lehrens und Lernens auf der Basis des WWW. Sie werden bereits seit längerer Zeit in vielen E-Learning-Projekten genutzt und halten seit kurzem auch vermehrt flächen deckenden Einzug in die deutschen Universitäten. In diesem Artikel werden zunächst die Eigenschaften und Vorteile von Lernmanagementsystemen im Allgemeinen erläutert. Anschließend wird auf den Einsatz des Open-Source-LMS Stud.IP an der Universität Oldenburg und die dabei gemachten Erfahrungen eingegangen.
Ieee Software, 2007
When introducing new technologies, small software development enterprises must pay attention to v... more When introducing new technologies, small software development enterprises must pay attention to version control.
Requirements Engineering, 1993
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Papers by Wilhelm Hasselbring