1,720,959 research outputs found
Using RIPE Atlas for Geolocating IP Infrastructure
Get PDFThe vast majority of studies on IP geolocation focuses on localizing the end-users, and little attention has been devoted to localizing the elements of the Internet infrastructure, i.e., the routers and servers that make the Internet work. In this paper, we study the maximum theoretical accuracy that can be achieved by a geolocation approach aimed at geolocating the Internet infrastructure. In particular, we study the effects on localization accuracy produced by the position of landmarks and by the strategy followed for their enrollment. We compare two main approaches: the first is more centralized and controlled, and uses well-connected machines belonging to the infrastructure as landmarks; the second is more distributed and scalable and is based on landmarks positioned at the edge of the network. The study is based on an extensive set of measurements collected using the RIPE Atlas platform. The results show that the uniform and widespread diffusion of landmarks can be as important as their measurement accuracy. The study is carried out at both the worldwide and regional scale, including regions that were scarcely observed in the past. The results highlight that the geographical characteristics of the Internet paths are dependent on the considered region, thus suggesting the use of specifically calibrated models. Finally, the study shows that geolocating IP infrastructure with active measurements is feasible in terms of precision and scalability of the overall system
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Radian: Visual Exploration of Traceroutes
Get PDFSeveral projects deploy probes in the Internet. Probes are systems that continuously perform traceroutes and other networking measurements (e.g. ping) towards selected targets. Measurements can be stored and analyzed to gain knowledge on several aspects of the Internet, but making sense of such data requires suitable methods and tools for exploration and visualization. We present Radian, a tool that allows to visualize traceroute paths at different levels of detail and to animate their evolution during a selected time interval. We also describe extensive tests of the tool using traceroutes performed by RIPE Atlas Internet probes
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Long-Lasting Sequences of BGP Updates
No full textThe Border Gateway Protocol (BGP) is the protocol that makes the various networks composing the Internet communicate to each other. Routers speaking BGP exchange updates to keep the routing up-to-date and allow such communication. This usually is done to reflect changes in the routing configurations or as a consequence of link failures. In the Internet as a whole it is normal that BGP updates are continuously exchanged, but for any specific IP prefix, these updates are supposed to be concentrated in a short time interval that is needed to react to a network change. On the contrary, in this paper we show that there are many IP prefixes involved in quite long sequences consisting of a large number of BGP updates. Namely, examining ~30 billion updates collected by 172 observation points distributed worldwide, we estimate that almost 30% of them belong to sequences lasting more than one week. Such sequences involve 222285 distinct IP prefixes, approximately one fourth of the number of announced prefixes. We detect such sequences using a method based on the Discrete Wavelet Transform. We publish an online tool for the exploration and visualization of such sequences, which is open to the scientific community for further research. We empirically validate the sequences and report the results in the same online resource.The analysis of the sequences shows that almost all the observation points are able to see a large amount of sequences, and that 53% of the sequences last at least two weeks
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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