Balanced data assimilation for highly-oscillatory mechanical systems

Data assimilation algorithms are used to estimate the states of a dynamical system using partial and noisy observations. The ensemble Kalman filter has become a popular data assimilation scheme due to its simplicity and robustness for a wide range of application areas. Nevertheless, the ensemble Kalman filter also has limitations due to its inherent Gaussian and linearity assumptions. These limitations can manifest themselves in dynamically inconsistent state estimates. We investigate this issue in this paper for highly oscillatory Hamiltonian systems with a dynamical behavior which satisfies certain balance relations. We first demonstrate that the standard ensemble Kalman filter can lead to estimates which do not satisfy those balance relations, ultimately leading to filter divergence. We also propose two remedies for this phenomenon in terms of blended time-stepping schemes and ensemble-based penalty methods. The effect of these modifications to the standard ensemble Kalman filter are discussed and demonstrated numerically for two model scenarios. First, we consider balanced motion for highly oscillatory Hamiltonian systems and, second, we investigate thermally embedded highly oscillatory Hamiltonian systems. The first scenario is relevant for applications from meteorology while the second scenario is relevant for applications of data assimilation to molecular dynamics

A Persona-based Extension for Massive Open Online Courses in Accessible Design

AbstractIn this paper, we present a new participatory design for learning, developed in the context of a transnational initiative for creating Massive Open Online Courses (MOOCs) on Accessible Design for ICT. The core idea is creating an additional learning benefit by means of immersive learning experience. This is achieved by simulating scenarios, in which the participants in the MOOC course are prompted to take on the role of accessible media author, and user, vice versa. The approach is based on the concept of “personas”, a user centered design methodology that illustrates practical needs by portraying realistic personal profiles of hypothetical characters

Endophytes Are Hidden Producers of Maytansine in Putterlickia Roots

Several recent studies have lent evidence to the fact that certain so-called plant metabolites are actually biosynthesized by associated microorganisms. In this work, we show that the original source organism(s) responsible for the biosynthesis of the important anticancer and cytotoxic compound maytansine is the endophytic bacterial community harbored specifically within the roots of Putterlickia verrucosa and P. retrospinosa plants. Evaluation of the root endophytic community by chemical characterization of their fermentation products using HPLC-HRMSn, along with a selective microbiological assay using the maytansine-sensitive type strain Hamigera avellanea revealed the endophytic production of maytansine. This was further confirmed by the presence of AHBA synthase genes in the root endophytic communities. Finally, MALDI-imaging-HRMS was used to demonstrate that maytansine produced by the endophytes is typically accumulated mainly in the root cortex of both plants. Our study, thus, reveals that maytansine is actually a biosynthetic product of root-associated endophytic microorganisms. The knowledge gained from this study provides fundamental insights on the biosynthesis of so-called plant metabolites by endophytes residing in distinct ecological niches

Barrierefreiheit im MOOC

Massive Open Online Courses (MOOCs) sind darauf ausgelegt, im tertiären Bildungsbereich den Wissenserwerb zu fördern, ohne dass die formalen Strukturen einer Ausbildungseinrichtung relevant sind. Dazu werden die Teilnehmer nicht persönlich von Dozenten betreut, sondern sind selbstgesteuert, oder werden durch kollaborative Lernmethoden aktiviert. Der Leistungszwang ist daher geringer, die Anzahl derjenigen, die Kurse abbrechen, jedoch ungleich höher. Durchschnittlich schließen maximal 10% der Teilnehmer ihren MOOC-Kurs ab

Applied Social Robotics—Building Interactive Robots with LEGO Mindstorms

Kipp A, Schneider S. Applied Social Robotics—Building Interactive Robots with LEGO Mindstorms. In: Merdan M, Lepuschitz W, Koppensteiner G, Balogh R, eds. Robotics in Education. Advances in Intelligent Systems and Computing. 1st ed. Cham: Springer Nature; 2016: 29-40