On Constructing Persistent Identifiers with Persistent Resolution Targets

Persistent Identifiers (PID) are the foundation referencing digital assets in scientific publications, books, and digital repositories. In its realization, PIDs contain metadata and resolving targets in form of URLs that point to data sets located on the network. In contrast to PIDs, the target URLs are typically changing over time; thus, PIDs need continuous maintenance -- an effort that is increasing tremendously with the advancement of e-Science and the advent of the Internet-of-Things (IoT). Nowadays, billions of sensors and data sets are subject of PID assignment. This paper presents a new approach of embedding location independent targets into PIDs that allows the creation of maintenance-free PIDs using content-centric network technology and overlay networks. For proving the validity of the presented approach, the Handle PID System is used in conjunction with Magnet Link access information encoding, state-of-the-art decentralized data distribution with BitTorrent, and Named Data Networking (NDN) as location-independent data access technology for networks. Contrasting existing approaches, no green-field implementation of PID or major modifications of the Handle System is required to enable location-independent data dissemination with maintenance-free PIDs.Comment: Published IEEE paper of the FedCSIS 2016 (SoFAST-WS'16) conference, 11.-14. September 2016, Gdansk, Poland. Also available online: http://ieeexplore.ieee.org/document/7733372

An Exploratory Study of COVID-19 Misinformation on Twitter

During the COVID-19 pandemic, social media has become a home ground for misinformation. To tackle this infodemic, scientific oversight, as well as a better understanding by practitioners in crisis management, is needed. We have conducted an exploratory study into the propagation, authors and content of misinformation on Twitter around the topic of COVID-19 in order to gain early insights. We have collected all tweets mentioned in the verdicts of fact-checked claims related to COVID-19 by over 92 professional fact-checking organisations between January and mid-July 2020 and share this corpus with the community. This resulted in 1 500 tweets relating to 1 274 false and 276 partially false claims, respectively. Exploratory analysis of author accounts revealed that the verified twitter handle(including Organisation/celebrity) are also involved in either creating (new tweets) or spreading (retweet) the misinformation. Additionally, we found that false claims propagate faster than partially false claims. Compare to a background corpus of COVID-19 tweets, tweets with misinformation are more often concerned with discrediting other information on social media. Authors use less tentative language and appear to be more driven by concerns of potential harm to others. Our results enable us to suggest gaps in the current scientific coverage of the topic as well as propose actions for authorities and social media users to counter misinformation.Comment: 20 pages, nine figures, four tables. Submitted for peer review, revision

DISCRET: An Interactive Decision Support System for Discrete Alternatives Multicriteria Problems

This paper is one of the series of 11 Working Papers presenting the software for interactive decision support and software tools for developing decision support systems. These products constitute the outcome of the contracted study agreement between the System and Decision Sciences Program at IIASA and several Polish scientific institutions. The theoretical part of these results is presented in the IIASA Working Paper WP-88-071 entitled "Theory, Software and Testing Examples in Decision Support Systems" which contains the theoretical and methodological backgrounds of the software systems developed within the project. This paper presents the DISCRET system. This system has been designed to solve basic multicriteria choice problems in which a finite set of feasible alternatives is explicitly given and for each alternative the value of all criteria are known. The decision maker is assumed to be rational in the sense that he can accept a Pareto-optimal solution as his final solution of the problem. Such a decision problem is rather simple as long as the number of criteria and alternatives is small. However, if the number of alternatives and/or criteria grows, the human information processing capabilities may reach their limits and therefore decision support facilities need to be utilized to guarantee efficient decision making

Dispositif de protection d'un régulateur de tension série mettant en œuvre un transformateur de couplage à entrefer virtuel

International audienceLes régulateurs de tension série, qu'ils soient électromécaniques ou à convertisseurs statiques, constituent une solution pour améliorer la qualité de l'énergie. Cette source d'alimentation variable compense les perturbations de la tension du réseau dans lequel elle est insérée en injectant sa propre tension via un transformateur de couplage. Pour répondre à la problématique de la régulation de tension dans un contexte où l'intensité des courants de défaut peut être élevée, un régulateur de tension à électronique protégée par un entrefer virtuel est proposé. Dans ce cas, l'intégration d'une colonne de retour avec un entrefer virtuel au transformateur de couplage assure la fonction de protection du convertisseur électronique lors de défaut sur le réseau. Le concept d'entrefer virtuel repose sur la saturation locale d'un circuit magnétique dont les effets sont similaires à ceux d'un entrefer mécanique d'épaisseur variable. Cette saturation locale s'apparente donc à un by-pass magnétique qui modifie la circulation du flux dans le transformateur de couplage, selon les modes de fonctionnement