Komponentenarchitektur für verteilte Systeme

An der Fachhochschule Hamburg fuhren wir in der Informatik seit einigen Semestern das Projekt „SEVERS - Software-Engineering für die Versicherungswirtschaft“ im Ausbildungskontext durch. Nach Betrachtung der im Rahmen des GDV (Gesamtverband der Deutschen Versicherungswirtschaft) formulierten Versicherungs- Anwendungs-Architektur (VAA) entstand im Projekt eine eigene SEVERSAnwendungsarchitektur, die einige softwaretechnische Probleme der VAA vermeidet. Folgende Hauptziele wurden verfolgt: • Information-Hiding als zentrales Konstruktionsprinzip, • Verifizierbare und zertifizierbare Komponenten, • Entwurf einer Migrationsstrategie, • Verwendung aktueller Entwicklungsmethoden und Technologien für neue Komponenten. In diesem Beitrag wird die SEVERS-Architektur kurz vorgestellt und es werden einige Fragen diskutiert, die mit der Anwendungsentwicklung verteilter, komponentenbasierter Anwendungen und mit der Einbettung solcher Systeme in Informationsmärkte zu tun haben. Die Versicherungswirtschaft liefert für die hier geschilderte Architekturentwicklung den Anlaß und den ersten Anwendungskontext. Die vorgestellte Architektur ist aber übertragbar auf andere, ähnlich gelagerte Anwendungsfelder und damit Konferenz, GeNeMe 1998, Neue Medien, Web 2.0, E-Learningverallgemeinerbar

Energy balance closure for the LITFASS-2003 experiment

In the first part, this paper synthesises the main results from a series of previous studies on the closure of the local energy balance at low-vegetation sites during the LITFASS-2003 experiment. A residual of up to 25% of the available energy has been found which cannot be fully explained either by the measurement uncertainty of the single components of the surface energy balance or by the length of the flux-averaging period. In the second part, secondary circulations due to heterogeneities in the surface characteristics (roughness, thermal and moisture properties) are discussed as a possible cause for the observed energy balance non-closure. This hypothesis seems to be supported from the fluxes derived from area-averaging measurement techniques (scintillometers, aircraft)

The Arabidopsis leucine-rich repeat receptor-like kinase MIK2 is a crucial component of early immune responses to a fungal-derived elicitor

- Fusarium spp. cause severe economic damage in many crops, exemplified by Panama Disease of banana or Fusarium head blight of wheat. Plants sense immunogenic patterns (termed elicitors) at the cell surface to initiate pattern-triggered immunity (PTI). Knowledge of fungal elicitors and corresponding plant immune-signaling is incomplete but could yield valuable sources of resistance. - We characterized Arabidopsis thaliana PTI responses to a peptide elicitor fraction present in several Fusarium spp. and employed a forward-genetic screen using plants containing a cytosolic calcium reporter to isolate fusarium elicitor reduced elicitation (fere) mutants. - We mapped the causal mutation in fere1 to the leucine-rich repeat receptor-like kinase MDIS1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) and confirmed a crucial role of MIK2 in fungal elicitor perception. MIK2-dependent elicitor responses depend on known signaling components and transfer of AtMIK2 is sufficient to confer elicitor sensitivity to Nicotiana benthamiana. - Arabidopsis senses Fusarium elicitors by a novel receptor complex at the cell surface that feeds into common PTI pathways. These data increase mechanistic understanding of PTI to Fusarium and place MIK2 at a central position in Arabidopsis elicitor responses

Biventricular Assist Device Terminates Polymorphic Ventricular Tachycardia in Giant Cell Myocarditis

We present the case of a 55-year-old woman with giant cell myocarditis who experienced a rapid deterioration in her condition. As her heart failure progressed, she developed more ventricular ectopic beats, which culminated in a polymorphic ventricular tachycardia that did not improve despite immunosuppressive and antiarrhythmic therapy. Emergent biventricular assist device placement, however, did eliminate her arrhythmia

Die technische Infrastruktur zur Teilnahme von Unternehmen an Gemeinschaften in Neuen Medien

Ein Internet-Auftritt eines Unternehmens setzt voraus, daß bezüglich der internen Informations-Infrastruktur bestimmte organisatorische und technische Voraussetzungen erfüllt sind. In diesem Beitrag soll dargelegt werden, daß eine komponentenbasierte Anwendungsarchitektur wegen ihrer leichten Erweiterbarkeit und wegen ihrer Übersichtlichkeit den Internet-Auftritt und damit die Beteiligung an Medien-Gemeinschaften erheblich erleichtern kann. Dies wird anhand einer Prototypentwicklung dargestellt und um Sicherheitsbetrachtungen, die für einen professionellen Einsatz der entwickelten Konzepte unabdingbar sind, ergänzt

Beyond convergence rates: Exact recovery with Tikhonov regularization with sparsity constraints

The Tikhonov regularization of linear ill-posed problems with an $\ell^1$ penalty is considered. We recall results for linear convergence rates and results on exact recovery of the support. Moreover, we derive conditions for exact support recovery which are especially applicable in the case of ill-posed problems, where other conditions, e.g. based on the so-called coherence or the restricted isometry property are usually not applicable. The obtained results also show that the regularized solutions do not only converge in the $\ell^1$-norm but also in the vector space $\ell^0$ (when considered as the strict inductive limit of the spaces $\R^n$ as $n$ tends to infinity). Additionally, the relations between different conditions for exact support recovery and linear convergence rates are investigated. With an imaging example from digital holography the applicability of the obtained results is illustrated, i.e. that one may check a priori if the experimental setup guarantees exact recovery with Tikhonov regularization with sparsity constraints

Improving collisional growth in Lagrangian cloud models: development and verification of a new splitting algorithm

Lagrangian cloud models (LCMs) are increasingly used in the cloud physics community. They not only enable a very detailed representation of cloud microphysics but also lack numerical errors typical for most other models. However, insufficient statistics, caused by an inadequate number of Lagrangian particles to represent cloud microphysical processes, can limit the applicability and validity of this approach. This study presents the first use of a splitting and merging algorithm designed to improve the warm cloud precipitation process by deliberately increasing or decreasing the number of Lagrangian particles under appropriate conditions. This new approach and the details of how splitting is executed are evaluated in box and single-cloud simulations, as well as a shallow cumulus test case. The results indicate that splitting is essential for a proper representation of the precipitation process. Moreover, the details of the splitting method (i.e., identifying the appropriate conditions) become insignificant for larger model domains as long as a sufficiently large number of Lagrangian particles is produced by the algorithm. The accompanying merging algorithm is essential to constrict the number of Lagrangian particles in order to maintain the computational performance of the model. Overall, splitting and merging do not affect the life cycle and domain-averaged macroscopic properties of the simulated clouds. This new approach is a useful addition to all LCMs since it is able to significantly increase the number of Lagrangian particles in appropriate regions of the clouds, while maintaining a computationally feasible total number of Lagrangian particles in the entire model domain.</p