‚Linked Data‘ - und warum wir uns im hbz-Verbund damit beschäftigen

The topic “Linked Open Data“ is pushing more and more into the library sphere. While “Open Data“ is all about the legal status of any kind of data, “Linked Data“ aims at augmenting the interoperability of data by consistently applying (web-)standards. This article begins with an illustration of why “Linked Data“ is relevant to the library world. This is followed by a short introduction to the most important Linked Data standards and some thoughts on how to migrate bibliographic data to these standards. Finally the current activities of the hbz library network concerning this matter are presented

Zur Konzeption und Implementierung einer Infrastruktur für freie bibliographische Daten

The increasing awareness of the topic "Open Data" in the library world opens up important questions concerning the handling of open data. This article discusses the conceptual base lines of a technical Open Data infrastructure and work out the complex requirements such an infrastructure must meet. The covered aspects range from data publication and description to the versioning of open data. For some aspects promising points of contact are identified, e.g. in form of version control tools in the Open Source community or in form of running projects by the W3C or the Open Knowledge Foundation

A User Study on Explainable Online Reinforcement Learning for Adaptive Systems

Online reinforcement learning (RL) is increasingly used for realizing adaptive systems in the presence of design time uncertainty. Online RL facilitates learning from actual operational data and thereby leverages feedback only available at runtime. However, Online RL requires the definition of an effective and correct reward function, which quantifies the feedback to the RL algorithm and thereby guides learning. With Deep RL gaining interest, the learned knowledge is no longer explicitly represented, but is represented as a neural network. For a human, it becomes practically impossible to relate the parametrization of the neural network to concrete RL decisions. Deep RL thus essentially appears as a black box, which severely limits the debugging of adaptive systems. We previously introduced the explainable RL technique XRL-DINE, which provides visual insights into why certain decisions were made at important time points. Here, we introduce an empirical user study involving 54 software engineers from academia and industry to assess (1) the performance of software engineers when performing different tasks using XRL-DINE and (2) the perceived usefulness and ease of use of XRL-DINE.Comment: arXiv admin note: substantial text overlap with arXiv:2210.0593

Poecilia picta, a Close Relative to the Guppy, Exhibits Red Male Coloration Polymorphism: A System for Phylogenetic Comparisons

Studies on the evolution of female preference and male color polymorphism frequently focus on single species since traits and preferences are thought to co-evolve. The guppy, Poecilia reticulata, has long been a premier model for such studies because female preferences and orange coloration are well known to covary, especially in upstream/downstream pairs of populations. However, focused single species studies lack the explanatory power of the comparative method, which requires detailed knowledge of multiple species with known evolutionary relationships. Here we describe a red color polymorphism in Poecilia picta, a close relative to guppies. We show that this polymorphism is restricted to males and is maintained in natural populations of mainland South America. Using tests of female preference we show female P. picta are not more attracted to red males, despite preferences for red/orange in closely related species, such as P. reticulata and P. parae. Male color patterns in these closely related species are different from P. picta in that they occur in discrete patches and are frequently Y chromosome-linked. P. reticulata have an almost infinite number of male patterns, while P. parae males occur in discrete morphs. We show the red male polymorphism in P. picta extends continuously throughout the body and is not a Y-linked trait despite the theoretical prediction that sexually-selected characters should often be linked to the heterogametic sex chromosome. The presence/absence of red male coloration of P. picta described here makes this an ideal system for phylogenetic comparisons that could reveal the evolutionary forces maintaining mate choice and color polymorphisms in this speciose group

Preface: The disorder of mathematics education, Part II. Critique, imagination and play

The idea of conceiving mathematics education as a disorder evolved at a small conference held at the Freie Universität Berlin from January 15th to 17th in 2015. The conference aimed at destabilizing taken-for-granted truths that lay at the heart of mathematics education as a research field. While the socio-political branch proclaims a critique of mainstream mathematics education to be at the core of its collective identity , the common premise of the participants of the meeting was that the radicality of this critique is more often than not domesticized for the sake of ordering its object in a way that it suits well the storylines that are commonly narrated. The conference and the book that resulted from that conference (The disorder of mathematics education; Straehler-Pohl, Bohlmann & Pais 2017) had a clear focus: developing a critique of the status quo of mathematics education research, including, and perhaps more importantly, research within a sociopolitical vein

Entwicklung eines stufenübergreifenden Qualitätssicherungssystems für die ökologische Ernährungswirtschaft unter besonderer Berücksichtigung der Kommunikations- und Organisationsstrukturen

Im Rahmen des Projektes wurden Konzepte zur Lösung drängender Probleme im Bereich Qualitätssicherung in der Ökologischen Lebensmittelwirtschaft erarbeitet. Dazu wurden Strukturen geschaffen, die es erlaubten die Fachleute der Branche in die Problemanalyse und Lösungserarbeitung einzubeziehen. Durch die intensive Einbindung der Akteure konnte gewährleistet werden, dass die erarbeiteten Konzepte von hoher Relevanz für die Branche und direkt umsetzbar sind. Neben der Erarbeitung von Konzepten war deren Abstimmung mit Branchenvertretern und der Wissenstransfer der Ergebnisse ein Schwerpunkt des Projektes. Die Analyse der Kommunikations- und Organisationsstrukturen der Branche gab Hinweise darauf, welche Akteure von besonderer Relevanz sind, welche Kommunikationsmittel genutzt werden und wo Lücken in den Organisationsstrukturen bestehen. Das Projekt hat im Bereich Kontaminationen von Öko-Lebensmitteln mit Pflanzenschutzmittelrückständen Konzepte erarbeitet, die eine Reduktion der Einträge in Erzeugung und Verarbeitung ermöglichen. Die rechtliche Situation bei Haftungsfragen wurde in leicht verständlicher Form aufgearbeitet. Mit der Kommentierung des Anhang III Nr. 9 der EU-Öko-Verordnung wurden Vorschläge zur effizienten Verbesserung der Kontrollen vorgelegt und Grundlagen geschaffen, um die Auslegung des Gesetzes in EU und Bundesländern zu harmonisieren. Im Bereich Gentechnik wurde ein Konzept zur Verbraucherinformation erarbeitet, welches von den Akteuren der Branche umgesetzt wurde. Erarbeitet wurden weiterhin konkrete Vorschläge für die Weiterentwicklung der gesetzlichen Rahmenbedingungen im Gentechnikbereich, um die Ökologische Lebensmittelwirtschaft in ihrem Bestand zu sichern. Von der angestrebten „Koexistenz“ gehen erhebliche Gefahren für diesen Wirtschaftsbereich aus. Die Erstellung einer „Handlungsempfehlung zur Umsetzung von Maßnahmen der Warenrückverfolgbarkeit und Herkunftssicherung in Unternehmen der Ökologischen Lebensmittelwirtschaft“ ist Hauptergebnis in einem weiteren Bereich des Projekts. Mit dem erarbeiteten Krisenmanagementplan steht der Branche künftig ein Instrument zur Verfügung, den kommunikativen Teil einer Krise koordiniert zu bewältigen

Chemical interdiffusion between Na-series tephritic and phonolitic melts with different H2O content, temperature, and oxygen fugacity values

The diffusive exchange of major elements in Na-series tephrite–phonolite diffusion couples with compositions relevant to the Canary Islands magmatism was determined at 300 MPa and variable H2O concentrations (0.3 wt % to 3.3 wt %), temperatures (1150 to 1300 °C), and fO2 levels (NNO−1.5 to NNO+1.7). Composition-dependent effective binary diffusion coefficients were determined from concentration–distance profiles. Results show a wide range of diffusivities for different cations, consistently following the sequence Na Al K ≥ Mg = Fe = Ca > Si > Ti, with a mild diffusivity contrast (0.2–0.8 log units) between tephritic and phonolitic melts. Na is the fastest component, with diffusivities falling ∼ 1.0 log units above those of Si for any given condition. An anomalously fast Al diffusion is observed, with DAl falling ∼ 0.4 log units above Si and ∼ 0.6 log units below Na, suggesting a prevalence of Al–alkali coupling across our range of run conditions. The relationships between log D and H2O content in melt for all cations in an intermediate composition are strongly nonlinear and can be fitted using an exponential function with a convergence in diffusion coefficients for different temperatures with increasing H2O content. Thus, Arrhenius analyses result in a decrease in activation energies from 222–293 kJ mol−1 at 1.7 wt % H2O to 48–112 kJ mol−1 at 3.0 wt % H2O. These results provide new data on chemical interdiffusion in highly alkaline Na-rich melts and suggest that H2O content plays a key role in increasing the chemical efficiency of magma mixing at low temperatures. The obtained dataset is used to test chemical controls of magma mixing in the El Abrigo ignimbrite, Tenerife, where banded pumices involving basanitic–tephritic to phonolitic magmas are common in several compositionally bimodal ignimbrite units

Preface: The disorder of mathematics education, Part II. Critique, imagination and play

The idea of conceiving mathematics education as a disorder evolved at a small conference held at the Freie Universität Berlin from January 15th to 17th in 2015. The conference aimed at destabilizing taken-for-granted truths that lay at the heart of mathematics education as a research field. While the "socio-political branch" proclaims a critique of "mainstream" mathematics education to be at the core of its "collective identity", the common premise of the participants of the meeting was that the radicality of this critique is more often than not domesticized for the sake of ordering its object in a way that it suits well the storylines that are commonly narrated. The conference and the book that resulted from that conference (The disorder of mathematics education; Straehler-Pohl, Bohlmann & Pais 2017) had a clear focus: developing a critique of the status quo of mathematics education research, including, and perhaps more importantly, research within a sociopolitical vein

Boosting the performance of Ni/Al2O3 for the reverse water gas shift reaction through formation of CuNi nanoalloys

Ni supported on alumina is extensively employed as a catalyst for the reverse water gas shift reaction. However, the formation of inactive Ni aluminates and the high selectivity to methane affects the performance of these catalysts, especially at low reaction temperatures. In this study, Cu is employed as an effective enhancer of the catalytic performance, promoting the reducibility of Ni, and suppressing methane production through the formation of stable CuNi nanoalloys. The synergy between both metals suppresses consecutive hydrogenation, reaching conversions close to equilibrium and 100% selectivity to carbon monoxide. At 500 °C, the CO yield of the Cu25Ni75/Al2O3 catalyst was twice that of Ni/Al2O3, with only half the hydrogen consumption. The formation of CuNi nanoalloys was confirmed by HAADF STEM–EDS, without segregation in monometallic phases even after 30 h time on stream. Similarly, Cu50Ni50/Al2O3 remained alloyed after the reaction. However, the catalytic activity decreased due to sintering, in agreement with a higher Cu content. This effect was significantly more pronounced for Cu75Ni25/Al2O3 and Cu/Al2O3, with formation of large particles and consequent loss of active surface area.TU Berlin, Open-Access-Mittel – 2021DFG, 390540038, EXC 2008: Unifying Systems in Catalysis "UniSysCat