OCLC, WorldCat und die Metadaten-Kontroverse

The article gives an overview over the background, genesis, content and critic of OCLC's proposed metadata policy for WorldCat records. In the end it poses questions for an approach on licensing bibliographic data in germany

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

‚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

Bibliotheken: Wir öffnen Daten. Zum Stand der Entwicklung einer offenen Dateninfrastruktur

In den letzten Jahren haben sich – gerade in Deutschland – viele Bibliotheken und insbesondere Verbundzentralen entschlossen, bibliothekarische Daten unter einer offenen Lizenz zu publizieren und/oder als Linked Data aufzubereiten. Dieser Beitrag versucht, diese Aktivitäten in einem größeren Kontext zu sehen, indem er Open Data als eines von mehreren Elementen einer „offenen Dateninfrastruktur“ versteht. Es werden sieben Elemente einer Dateninfrastruktur skizziert und eingeschätzt, wie offen die einzelnen Elemente gegenwärtig in Deutschland sind. Abschließend wird am Beispiel von (Open) Discovery vorgeführt, wie offene Ansätze bestehende Probleme beheben könnten und welche Handlungsmöglichkeiten es gibt. During the last years many libraries and especially library service centers have decided to publish library data under an open license and/or to expose it as linked data. This paper tries to put these activities in a bigger context by viewing open data as one element of an open data infrastructure. Seven elements of data infrastuctures are outlined and their approximate level of openness in Germany is assessed. Finally, it is demonstrated – using (open) discovery as an example – how open approaches can fix existing problems and which possibilities there are for practical actions

Bibliotheks- und Informationspraxis

Das Buch ist sowohl eine Einführung in die Themen Linked Data, Open Data und Open Linked Data als es auch den konkreten Bezug auf Bibliotheken behandelt. Hierzu werden konkrete Anwendungsprojekte beschrieben. Der Band wendet sich dabei sowohl an Personen aus der Bibliothekspraxis als auch an Personen aus dem Bibliotheksmanagement, die noch nicht mit dem Thema vertraut sind

Convergence proof for stochastic gradient descent in the training of deep neural networks with ReLU activation for constant target functions

In many numerical simulations stochastic gradient descent (SGD) type optimization methods perform very effectively in the training of deep neural networks (DNNs) but till this day it remains an open problem of research to provide a mathematical convergence analysis which rigorously explains the success of SGD type optimization methods in the training of DNNs. In this work we study SGD type optimization methods in the training of fully-connected feedforward DNNs with rectified linear unit (ReLU) activation. We first establish general regularity properties for the risk functions and their generalized gradient functions appearing in the training of such DNNs and, thereafter, we investigate the plain vanilla SGD optimization method in the training of such DNNs under the assumption that the target function under consideration is a constant function. Specifically, we prove under the assumption that the learning rates (the step sizes of the SGD optimization method) are sufficiently small but not $L^1$-summable and under the assumption that the target function is a constant function that the expectation of the riskof the considered SGD process converges in the training of such DNNs to zero as the number of SGD steps increases to infinity.Comment: 71 pages, 5 figures, 2 tables, 4 Python source codes. To appear in Electronic Research Archiv

lobid-gnd – Eine Schnittstelle zur Gemeinsamen Normdatei für Mensch und Maschine

Mit lobid-gnd bietet das Hochschulbibliothekszentrum des Landes Nordrhein-Westfalen (hbz) eine Schnittstelle zur Gemeinsamen Normdatei (GND) für Mensch und Maschine an. In diesem Beitrag werden detailliert die Nutzungsmöglichkeiten von lobid-gnd beleuchtet. Vorgestellt werden die graphische Nutzeroberfläche, Möglichkeiten komplexer Abfragen gegen die Web-API und die Integration in OpenRefine. Darüber hinaus beschreiben wir den Prozess der Datengenerierung auf Basis des Linked-Data-Angebots der Deutschen Nationalbibliothek (DNB)

lobid – Dateninfrastruktur für Bibliotheken

lobid ist der zentrale Anlaufpunkt für die Linked-Open-Data-Dienste des Hochschulbibliothekszentrums des Landes Nordrhein-Westfalen (hbz). Das Akronym „lobid" steht für „Linking Open Bibliographic Data“. lobid umfasst Rechercheoberflächen für Anwender und Web-APIs.Die lobid-Dienste bieten Zugriff auf die Titeldaten des hbz-Verbundkatalogs, Beschreibungen von bibliothekarischen Organisationen und anderen Gedächtnisinstitutionen aus dem Sigelverzeichnis und der Deutschen Bibliotheksstatistik (DBS) sowie auf die Gemeinsame Normdatei (GND). Die Datensets können so in verschiedenen Kontexten einheitlich (JSON-LD über HTTP) genutzt und eingebunden werden. Vielfältige Möglichkeiten der Datenabfrage werden unterstützt.Der Artikel beschreibt zunächst die technischen Hintergründe der Bereitstellung von lobid und die Erfahrungen, die bei der Transformation verschiedener Datensets nach JSON-LD gemacht wurden. Vorgestellt wird auch der Entwicklungsprozess und die Art und Weise der Dokumentation der Dienste

Testing the link between terrestrial climate change and Galactic spiral arm transit

We re-examine past suggestions of a close link between terrestrial climate change and the Sun's transit of spiral arms in its path through the Milky Way galaxy. These links produced concrete fits, deriving the unknown spiral pattern speed from terrestrial climate correlations. We test these fits against new data on spiral structure based on CO data that does not make simplifying assumptions about symmetry and circular rotation. If we compare the times of these transits to changes in the climate of Earth, not only do the claimed correlations disappear, but also we find that they cannot be resurrected for any reasonable pattern speed.Comment: Accepted for publication in ApJ Letters. Moderate revisions with clarification, no change in conclusion

Observed Changes in the Lifetime and Amplitude of the Madden–Julian Oscillation Associated with Interannual ENSO Sea Surface Temperature Anomalies

The Madden-Julian Oscillation (MJO) is analysed using the reanalysis zonal wind and satellite outgoing longwave radiation-based indices of Wheeler and Hendon for the 1974-2005 period. The average life time of MJO events varies with season, being 36 days for events whose central date occurs in December, and 48 days for events in September. The life time of the MJO in the equinoctial seasons (March-May and October-December) is also dependent on the state of the El Nino-Southern Oscillation (ENSO). During October-December it is only 32 days under El Nino conditions, increasing to 48 days under La Nina conditions, with similar values in northern spring. This difference is due to faster eastward propagation of the MJO convective anomalies through the Maritime Continent and western Pacific during El Nino, consistent with theoretical arguments concerning equatorial wave speeds. The analysis is extended back to 1950 by using an alternative definition of the MJO based on just the zonal wind component of the Wheeler and Hendon indices. A rupture in the amplitude of the MJO is found in 1975, at the same time as the well known rupture in the ENSO time series, that has been associated with the Pacific Decadal Oscillation. The mean amplitude of the MJO is 16% larger in the post-rupture period (1976-2005) compared to the pre-rupture period (1950-1975). Before the 1975 rupture, the amplitude of the MJO is a maximum (minimum) under El Nino (La Nina) conditions during northern winter, and a minimum (maximum) under El Nino (La Nina) conditions during northern summer. After the rupture, this relationship disappears. When the MJO-ENSO relationship is analysed using all year round data, or a shorter data set, as in some previous studies, no relationship is found