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Search Results: 1 - 10 of 1020 matches for " Wilhelm Hasselbring "
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Formalization of Federated Schema Architectural Style Variability  [PDF]
Wilhelm Hasselbring
Journal of Software Engineering and Applications (JSEA) , 2015, DOI: 10.4236/jsea.2015.82009
Abstract: Data integration requires managing heterogeneous schema information. A federated database system integrates heterogeneous, autonomous database systems on the schema level, whereby both local applications and global applications accessing multiple component database systems are supported. Such a federated database system is a complex system of systems which requires a well-designed organization at the system and software architecture level. A specific challenge that federated database systems face is the organization of schemas into a schema architecture. This paper provides a detailed, formal investigation of variability in the family of schema architectures, which are central components in the architecture of federated database systems. It is shown how the variability of specific architectures can be compared to the reference architecture and to each other. To achieve this, we combine the semi-formal object-oriented modeling language UML with the formal object-oriented specification language Object-Z. Appropriate use of inheritance in the formal specification, as enabled by Object-Z, greatly supports specifying and analyzing the variability among the studied schema architectures. The investigation also serves to illustrate the employed specification techniques for analyzing and comparing software architecture specifications.
Runtime Reconfiguration of J2EE Applications
Jasminka Matevska-Meyer,Sascha Olliges,Wilhelm Hasselbring
Computer Science , 2004,
Abstract: Runtime reconfiguration considered as "applying required changes to a running system" plays an important role for providing high availability not only of safety- and mission-critical systems, but also for commercial web-applications offering professional services. Hereby, the main concerns are maintaining the consistency of the running system during reconfiguration and minimizing its down-time caused by the reconfiguration. This paper focuses on the platform independent subsystem that realises deployment and redeployment of J2EE modules based on the new J2EE Deployment API as a part of the implementation of our proposed system architecture enabling runtime reconfiguration of component-based systems. Our "controlled runtime redeployment" comprises an extension of hot deployment and dynamic reloading, complemented by allowing for structural change
Performance-oriented DevOps: A Research Agenda
Andreas Brunnert,Andre van Hoorn,Felix Willnecker,Alexandru Danciu,Wilhelm Hasselbring,Christoph Heger,Nikolas Herbst,Pooyan Jamshidi,Reiner Jung,Joakim von Kistowski,Anne Koziolek,Johannes Kro?,Simon Spinner,Christian V?gele,Jürgen Walter,Alexander Wert
Computer Science , 2015,
Abstract: DevOps is a trend towards a tighter integration between development (Dev) and operations (Ops) teams. The need for such an integration is driven by the requirement to continuously adapt enterprise applications (EAs) to changes in the business environment. As of today, DevOps concepts have been primarily introduced to ensure a constant flow of features and bug fixes into new releases from a functional perspective. In order to integrate a non-functional perspective into these DevOps concepts this report focuses on tools, activities, and processes to ensure one of the most important quality attributes of a software system, namely performance. Performance describes system properties concerning its timeliness and use of resources. Common metrics are response time, throughput, and resource utilization. Performance goals for EAs are typically defined by setting upper and/or lower bounds for these metrics and specific business transactions. In order to ensure that such performance goals can be met, several activities are required during development and operation of these systems as well as during the transition from Dev to Ops. Activities during development are typically summarized by the term Software Performance Engineering (SPE), whereas activities during operations are called Application Performance Management (APM). SPE and APM were historically tackled independently from each other, but the newly emerging DevOps concepts require and enable a tighter integration between both activity streams. This report presents existing solutions to support this integration as well as open research challenges in this area.
Kinetic Study of the Aldol Condensation of Isobutyraldehyde Catalyzed by Sodium Hydroxide  [PDF]
Wilhelm J. Tic
Advances in Chemical Engineering and Science (ACES) , 2016, DOI: 10.4236/aces.2016.64041
Abstract: The initial step of works on the designing of a mathematical model of a commercial process to manufacture a mixture of butyric acid hydroxyesters, for use in ecological solvent compositions for the paint and varnish industry, is presented in the paper. The works referred to in this paper relate the mathematical model of the condensation reactor. A unit process kinetic model was designed based on an analysis of the general differential form of the equation of the reactor mass balance and an analysis of the mechanism of the Tishchenko aldol condensation reaction, as used in the synthesis of butyric acid hydroxyesters, confirmed by the results of GC/MS analysis. The forms of the kinetic equations obtained were verified experimentally by determining the values of the respective reaction rate constants.
Climate change in urban areas. Part 2, Measures
Wilhelm Kuttler
Environmental Sciences Europe , 2011, DOI: 10.1186/2190-4715-23-21
Abstract: In Teil 2 werden anhand verschiedener Beispiele Ma?nahmen gegen den globalen Klimawandel auf lokaler, insbesondere st?dtischer Ebene, vorgestellt. Im Wesentlichen handelt es sich dabei um M?glichkeiten, trockener Hitze und hohen Strahlungsintensit?ten durch Beschattung, aber auch durch Aufhellung von Oberfl?chen zu begegnen. Dabei wird zwischen objekt- und fl?chenbezogene Ma?nahmen unterschieden. Eine besondere Rolle nimmt hierbei die Begrünung von Stra?enschluchten und Geb?uden ein. Auch wird exemplarisch untersucht, ob eine Nutzung der urbanen Untergrundw?rmeinsel als Energietr?ger sinnvoll ist.
Climate change in urban areas, Part 1, Effects
Wilhelm Kuttler
Environmental Sciences Europe , 2011, DOI: 10.1186/2190-4715-23-11
Abstract: Part 1 deals with the origins of the natural and anthropogenic greenhouse effects, presents the contributions of the two effects to global warming and discusses recent examples of climate development from the Ruhr metropolis. The climate changes projected by various numeric and statistical models include an increase in thermal stress for city-dwellers and a rise in convective precipitation with corresponding run-off peaks in summer. As regard air pollutants (e.g. O3, PM10), it will mainly be the concentration of the near-surface trace gas ozone which will be clearly increased with rising temperatures. In contrast, a close correlation between atmospheric fine dust concentrations (≤ PM10) and temperature changes has not yet been established.Part 2 of the publication indicates how global climate change can be effectively combated at the local level using a number of application-oriented examples. These include measures affecting both individual properties and whole areas with a view to reducing urban overheating and CO2 emissions.Ziel dieses Beitrags, der in zwei Teilen erfolgt, ist es, die Wirkungen des globalen Klimawandels auf einen Ballungsraum (Ruhrgebiet) zu untersuchen und Gegenmaβnahmen auf lokaler Ebene zu diskutieren.Im ersten Teil wird auf die Entstehung des natürlichen und anthropogenen Treibhauseffektes eingegangen und deren jeweilige Beitr?ge an der globalen überw?rmung herausgestellt. Exemplarisch wird auf die jüngere Klimaentwicklung in der Metropolregion Ruhr eingegangen. Zu den durch verschiedene numerische und statistische Modelle projizierten Klimaver?nderungen z?hlen auch die Zunahme thermischer Belastungen für die Stadtbev?lkerung sowie die Verst?rkung sommerlicher konvektiver Niederschl?ge mit entsprechenden Abflussspitzen. Unter den Luftverunreinigungen wird es in erster Linie das bodennahe Spurengas Ozon sein, dass bei ansteigenden Temperaturen eindeutig h?here Konzentrationen erwarten l?sst, wohingegen die atmosph?rischen Feinstaubkonzentratio
The smallest chemical reaction system with bistability
Thomas Wilhelm
BMC Systems Biology , 2009, DOI: 10.1186/1752-0509-3-90
Abstract: Biological systems are based upon elementary mono- and bimolecular chemical reactions. In order to definitely clarify all necessary conditions for bistability we here present the corresponding minimal system. According to our definition, it contains the minimal number of (i) reactants, (ii) reactions, and (iii) terms in the corresponding ordinary differential equations (decreasing importance from i-iii). The minimal bistable system contains two reactants and four irreversible reactions (three bimolecular, one monomolecular).We discuss the roles of the reactions with respect to the necessary conditions for bistability: two reactions comprise the positive feedback loop, a third reaction filters out small stimuli thus enabling a stable 'off' state, and the fourth reaction prevents explosions. We argue that prevention of explosion is a third general necessary condition for bistability, which is so far lacking discussion in the literature.Moreover, in addition to proving that in two-component systems three steady states are necessary for bistability (five for tristability, etc.), we also present a simple general method to design such systems: one just needs one production and three different degradation mechanisms (one production, five degradations for tristability, etc.). This helps modelling multistable systems and it is important for corresponding synthetic biology projects.The presented minimal bistable system finally clarifies the often discussed question for the necessary conditions for bistability. The three necessary conditions are: positive feedback, a mechanism to filter out small stimuli and a mechanism to prevent explosions. This is important for modelling bistability with simple systems and for synthetically designing new bistable systems. Our simple model system is also well suited for corresponding teaching purposes.Bistability is key for understanding basic phenomena of cellular functioning, such as decision-making processes in cell cycle progression, cel
Digital publishing: tools and products
Wilhelm Ott
Poiesis & Praxis , 2008, DOI: 10.1007/s10202-007-0039-6
Abstract: Les publications électroniques ne sont pas accessibles sans auxiliaires techniques et nécessitent un entretien minutieux et constant ; un regard sur les supports et formats de données des 25 dernières années en témoigne. Plus récemment, le problème est l’objet de congrès et d’études. L’utilisation de formats de données standard, la neutralité des médias et des données indépendantes de plates-formes, de même que le centrage sur les données au lieu du centrage sur les processus sont les conditions d’une disponibilité à long terme. Pour les sciences humaines, les textes ne sont pas seulement source d’information, mais font eux-mêmes l’objet d’études scientifiques. C’est pourquoi leur publication dans un seul format de présentation ne suffit pas. Outre les instruments d’étude, de recherche et de navigation, il est nécessaire de disposer d’une forme de publication qui ne mette pas la présentation au premier plan, mais qui donne également accès au contenu et à la structure des documents publiés. Tant l’élaboration que l’analyse scientifique de tels documents requièrent des outils dont l’étendue excède ce que proposent les outils de publication et d’accès commerciaux. La flexibilité indispensable doit être garantie par la présence de fonctions de base dans le traitement de texte qui n’impliquent ni n’excluent aucun questionnement donné. Ceci est démontré par deux exemples d’analyse et de préparation de textes disponibles sous forme électronique.
Klaus D rner: Leben und sterben, wo ich hingeh re. Dritter Sozialraum und neues Hilfesystem []
Rimpau, Wilhelm
GMS Zeitschrift für Medizinische Ausbildung , 2007,
Roland Schiffter: Vom Leben, Leiden und Sterben in der Romantik. Neue Pathografien zur Romantischen Medizin []
Rimpau, Wilhelm
GMS Zeitschrift für Medizinische Ausbildung , 2009, DOI: 10.3205/zma000608
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