Online Exploration of Polygons with Holes

We study online strategies for autonomous mobile robots with vision to explore unknown polygons with at most h holes. Our main contribution is an (h+c_0)!-competitive strategy for such polygons under the assumption that each hole is marked with a special color, where c_0 is a universal constant. The strategy is based on a new hybrid approach. Furthermore, we give a new lower bound construction for small h.Comment: 16 pages, 9 figures, submitted to WAOA 201

On the number of simple cycles in planar graphs

Let CG denote the number of simple cycles of a graph G and let Cn be the maximum of CG over all planar graphs with n nodes We present a lower bound on Cn constructing graphs with at least n cycles Applying some probabilistic arguments we prove an upper bound of n We also discuss this question restricted to the subclasses of grid graphs bipartite graphs and of colorable triangulated graph

A high-temperature Mössbauer study into ionic and electronic disorder in BSCF5582

Perovskite-type compounds of the (Ba1-xSrx)(Co1-yFey)O3-δ family have been intensely investigated in respect to their mixed ionic-electronic conductivity and their oxygen disorder which is characterized by extremely high δ-values. The latter properties have made (Ba0.5Sr0.5)(Co0.857Fe0.08Fe0.12)O3-δ (BSCF5582) one of the most promising ceramic materials for oxygen separation membranes. We report on 57Fe Mössbauer in situ studies of BSCF5582 conducted between room temperature and 1000 °C in atmospheres of variable oxygen activity in order to obtain insight into local coordination and valence of iron at working conditions and into the distribution of oxygen vacancies on their different sites. The magnetically-split room-temperature Mössbauer spectra of BSCF5582 reveal the presence of two inequivalent iron species and show significant changes with oxygen content [1]. Evaluation of signal intensities confirms results from theoretical computations on vacancy formation in BSCF which indicate that formation energies of the various types of oxygen vacancies differ by the order of 0.1 eV only [2,3]. The spectral analysis also shows that the distribution of oxygen vacancies on the different sites of the perovskite structure of BSCF is far from random [1]. In the paramagnetic high-temperature phase (T ≥ 320 °C), the quadrupole-split signals demonstrate that local symmetry is lower than cubic. At 700, 850, and 1000°C, the spectra have been collected as a function of oxygen activity, aO2 (5·10−5 ≤ aO2 ≤ 1). Isomer shifts (IS) as well as quadrupole splittings (QS) were found almost independent of aO2. This unexpected finding is discussed in respect to simultaneous, stoichiometry-related changes in valence and local coordination of the iron probes. The isothermal decrease of signal intensity observed with increasing oxygen deficit is attributed to changes in the vibrational properties of the highly oxygen-deficient material. 1. P. Gaczynski, A. Harpf, J. Boer, R. Kircheisen, R. Kriegel, K.-D. Becker, 57Fe Mössbauer study into oxygen vacancy disorder of (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ, Solid State Ionics 316C (2018) 59-65. 2. E.A. Kotomin, Y.A. Mastrikov, M.M. Kuklja, R. Merkle, A. Roytburd, J. Maier, First principles calculation of oxygen vacancy formation and migration in mixed conducting (Ba0.5Sr0.5)(Co1−yFey)O3−δ perovskites, Solid State Ionics 188 (2011) 1-5. 3.Y.A. Mastrikov, M.M. Kuklja, E.A. Kotomin, J. Maier, First-principles modelling of complex perovskite (Ba0.5Sr0.5) (Co1−yFey)O3−δ for oxide fuel cell and gas separation membrane applications, Energy Environ. Sci. 3 (2010) 1544-1550

Kultur als Blickwinkel in interkulturell orientierten Lernsettings: didaktische und theoretische Reflexionen am Beispiel einer Ausbildung in Interkultureller Mediation

Wenn wir Kultur als Sehweise in eine Ausbildung einbringen, dann eröffnen sich Chancen, mit Hilfe theoretisch anspruchsvoller Konzepte komplexe Interaktionssituationen zu bearbeiten. Wie nun Kultur als Perspektive in einer praxisorientierten interkulturellen Mediationsausbildung verankert werden kann, das zeigt dieser Aufsatz. Deutlich werden soll dabei, wie ein multiperspektivischer Zugang zu Kultur Inhalte, Aufbau und Didaktik einer Ausbildung sowie den Gegenstand selbst umfassend verändert.If we integrate culture as a way of seeing into training, we get the chance to handle the most intriguing and complex interactions of humans with the aid of exigent theoretical concepts. This essay wants to show how culture can be conceptualized as a way of seeing or perspective within an intercultural mediation training. We argue that a multiperspective approach of culture will thoroughly transform contents, structure and methodology of the training as well as mediation itself

Culture as a way of seeing in intercultural learning settings. A didactic and theoretical approach using the example of a training in intercultural mediation

Wenn wir Kultur als Sehweise in eine Ausbildung einbringen, dann eröffnen sich Chancen, mit Hilfe theoretisch anspruchsvoller Konzepte komplexe Interaktionssituationen zu bearbeiten. Wie nun Kultur als Perspektive in einer praxisorientierten interkulturellen Mediationsausbildung verankert werden kann, das zeigt dieser Aufsatz. Deutlich werden soll dabei, wie ein multiperspektivischer Zugang zu Kultur Inhalte, Aufbau und Didaktik einer Ausbildung sowie den Gegenstand selbst umfassend verändert.If we integrate culture as a way of seeing into training, we get the chance to handle the most intriguing and complex interactions of humans with the aid of exigent theoretical concepts. This essay wants to show how culture can be conceptualized as a way of seeing or perspective within an intercultural mediation training. We argue that a multiperspective approach of culture will thoroughly transform contents, structure and methodology of the training as well as mediation itself