DBpedia's triple pattern fragments: usage patterns and insights

Queryable Linked Data is published through several interfaces, including SPARQL endpoints and Linked Data documents. In October 2014, the DBpedia Association announced an official Triple Pattern Fragments interface to its popular DBpedia dataset. This interface proposes to improve the availability of live queryable data by dividing query execution between clients and servers. In this paper, we present a usage analysis between November 2014 and July 2015. In 9 months time, the interface had an average availability of 99.99 %, handling 16,776,170 requests, 43.0% of which were served from cache. These numbers provide promising evidence that low-cost Triple Pattern Fragments interfaces provide a viable strategy for live applications on top of public, queryable datasets

Type-Constrained Representation Learning in Knowledge Graphs

Large knowledge graphs increasingly add value to various applications that require machines to recognize and understand queries and their semantics, as in search or question answering systems. Latent variable models have increasingly gained attention for the statistical modeling of knowledge graphs, showing promising results in tasks related to knowledge graph completion and cleaning. Besides storing facts about the world, schema-based knowledge graphs are backed by rich semantic descriptions of entities and relation-types that allow machines to understand the notion of things and their semantic relationships. In this work, we study how type-constraints can generally support the statistical modeling with latent variable models. More precisely, we integrated prior knowledge in form of type-constraints in various state of the art latent variable approaches. Our experimental results show that prior knowledge on relation-types significantly improves these models up to 77% in link-prediction tasks. The achieved improvements are especially prominent when a low model complexity is enforced, a crucial requirement when these models are applied to very large datasets. Unfortunately, type-constraints are neither always available nor always complete e.g., they can become fuzzy when entities lack proper typing. We show that in these cases, it can be beneficial to apply a local closed-world assumption that approximates the semantics of relation-types based on observations made in the data

Linked Data - the story so far

The term “Linked Data” refers to a set of best practices for publishing and connecting structured data on the Web. These best practices have been adopted by an increasing number of data providers over the last three years, leading to the creation of a global data space containing billions of assertions— the Web of Data. In this article, the authors present the concept and technical principles of Linked Data, and situate these within the broader context of related technological developments. They describe progress to date in publishing Linked Data on the Web, review applications that have been developed to exploit the Web of Data, and map out a research agenda for the Linked Data community as it moves forward

Innovationen im Kontext von Nachhaltigkeit

Innovationen sind das Kernelement des Überlebens und der Positionierung von Volkswirtschaften, da sie zur Befriedigung der Marktbedürfnisse beitragen. Vor dem Hintergrund knapper Ressourcen werden jedoch regelmäßig nur die Innovationen realisiert, die aus einer betriebswirtschaftlichen Betrachtung vorteilhaft erscheinen und damit weniger als eigentlich sinnvoll wären. Zunehmend setzt sich allerdings die Erkenntnis durch, dass die betriebswirtschaftliche Marktabgrenzung und damit die traditionelle Wirtschaftlichkeitsbewertung von Innovationen und Innovationsprojekten zu eng sind. Vielmehr erfordert die heutige Innovationsbewertung eine Erweiterung um soziale und ökologische Aspekt, also eine nachhaltige Ausrichtung. Basierend auf dem Forschungsprojekt Nachhaltigkeitsorientierte Bewertung von Innovationsprojekten (NaBI) gibt dieses Papier einen Überblick über das Forschungsfeld und analysiert die Nachhaltigkeitstheorie im Hinblick auf Innovationen. Im Ergebnis wird die Festlegung auf ein bestimmtes Indikatorset für die jeweilige Nachhaltigkeitsebene (Satellitensystem) vorgeschlagen, in denen essenzielle Bestandteile mit festgelegten Grenzwerten vorgegeben sind

Tracing fairness intentions: Chinese whisper

The paper aims at defining the role of intentions for reciprocity. The ultimatum game is modified, by adding a kind of randomizer (Chinese Whisper), to generate outcomes which are not intended und thus to separate the proposers' initial intentions from their actual offers. The mechanism ensures that the responder reacts to changing intentions and not to changing outcomes. This experimental approach also has the advantage that the number of available options for the proposer is not limited. Our evidence supports the view that fairness theory should explicitly address intentions responders exhibit different acceptance rates depending on the intentions of proposers

Für eine pragmatische Politik der Steuervereinfachung: Ein Darmstädter Entwurf

Steuervereinfachungen sind en vogue. Die bisherigen großen Würfe wie der „Karlsruher Entwurf“ oder der „Heidelberger Entwurf“ zur Einkommen- bzw. Einfachsteuer dürften indes geringe Chancen auf politische Umsetzung haben. Kilian Bizer und Jürgen Lyding stellen den „Darmstädter Entwurf“ für eine pragmatische Politik der Steuervereinfachung vor. --

Lock-in effects in competitive bidding schemes for payments for ecosystem services: Revisiting the fundamental transformation

Competitive bidding is considered to be a cost-effective allocation mechanism for payments for ecosystem services. This article shows that competition is not a necessary condition for sustaining cost-effectiveness in the long run. In a repeated conservation auction, learning, specific investments and the creation of social capital bias the chances of winning a follow-up contract in favour of former auction winners. Applying the concept of fundamental transformation (Williamson 1985), we argue that this asymmetry weakens competition and leads to lock-in effects between the auctioning agency and a stable pool of sellers with uncertain consequences for cost-effectiveness. We compare data from two laboratory experiments on auction-based conservation programmes and show under which conditions lock-in effects are likely to occur in a controlled environment. Our findings demonstrate lock-in effects do not erode the effectiveness of an auction but change the rules of the game towards more favourable conditions for the provision of the targeted good or service. In view of the empirical evidence for a superior performance of long-term contract relationships compared to low-cost short-term contracting, we discuss directions for follow-up empirical work

Exploring scholarly data with Rexplore.

Despite the large number and variety of tools and services available today for exploring scholarly data, current support is still very limited in the context of sensemaking tasks, which go beyond standard search and ranking of authors and publications, and focus instead on i) understanding the dynamics of research areas, ii) relating authors ‘semantically’ (e.g., in terms of common interests or shared academic trajectories), or iii) performing fine-grained academic expert search along multiple dimensions. To address this gap we have developed a novel tool, Rexplore, which integrates statistical analysis, semantic technologies, and visual analytics to provide effective support for exploring and making sense of scholarly data. Here, we describe the main innovative elements of the tool and we present the results from a task-centric empirical evaluation, which shows that Rexplore is highly effective at providing support for the aforementioned sensemaking tasks. In addition, these results are robust both with respect to the background of the users (i.e., expert analysts vs. ‘ordinary’ users) and also with respect to whether the tasks are selected by the evaluators or proposed by the users themselves