1,720,992 research outputs found
The benthic foraminifers of the Gulf of Policastro (Southern Tyrrhenian Sea, Italy)
No full textThe benthic foraminiferal assemblages of the Gulf of Policastro have been studied and particular attention has been paid to continental shelf sediments sampled by a Shipek grab-sampler in the vicinity of major river outfalls and two stations that were not subjected to fresh-water discarge. The samples were preserved in 4% formol and Rose Bengal in order to compare the biocoenoses and thanatocoenoses. The assemblages showed areal and bathymetric differences that may be determined by different environmental factors such as grain size, fresh-water discharge and the presence of algal populations. By taking into considerations the previous parameteres, we have been able to define dominant assemblages for different habitats. Moreover, it was possible to determine that the influence that fresh-water disharge had on species assemblages was confined to the circalittoral area
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
On the Incompleteness of the AS-level graph: a Novel Methodology for BGP Route Collector Placement
No full textIn the last decade many studies have used the Internet AS-level topology to perform several analyses, from the discovery of its graph properties to its impact on the effectiveness
of worm-containment strategies. Yet the BGP data typically used to reveal the topologies are far from being complete. Our contribution is three-fold. Firstly, we analyze BGP data currently gathered by RouteViews, RIPE RIS and PCH route collectors, and investigate the reasons for its incompleteness.
We found that large areas of the Internet are not properly
captured due to the geographic placement of the feeders and to BGP filters, such as BGP export policies and BGP decision processes. Secondly, given the incompleteness of data
available, we design a novel algorithm for selecting the optimal number of ASes that should join a route collector project to obtain a view of the Internet AS level topology that is closer to reality. We applied this algorithm to the global
topology and to five regional AS-level topologies, highlighting that the particular characteristics of the Internet at a regional level cannot be ignored during this process. Thirdly,
we provide a characterization of the ASes that we found to
be part of at least an optimal solution set, and highlight the characteristics of a typical AS that should join a route collector project. By analyzing these ASes we found that the current route collector infrastructure is rarely connected to them, highlighting that much more effort should be made in
devising an ideal route collector infrastructure that ideally would be able to capture a complete view of the Internet
The representation of the territory as an instrument of survey of the Unesco heritage in Montenegro on the Adriatic coast.
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
ICE: A memory-efficient BGP route collecting engine
No full textSince their deployment, BGP route collectors have played a fundamental role in investigating and detecting routing accidents and hijack attempts. However, an increasing number of detection techniques designed for real-time environments show that the lack of interactivity of route collectors represents a limitation to their efficacy, together with the small amount of sources from which data is collected. Both issues stem from the current implementation of route collectors, which relies on single-threaded and general-purpose routing suites to establish BGP sessions and collect data. With this implementation any interactive operation impacts on the collection process and the number of sessions that can be established is limited by memory usage, which is not optimized for route collecting purposes. In this paper we present ICE, a multi-threaded and memory-efficient BGP collecting engine which allows route collectors to overcome the above mentioned limitations. The multi-threaded environment allows us to solve the lack of interactiveness, allowing concurrent read/write operations. Memory efficiency has been obtained thanks to the design of a variant of the Liv-Zempel compression algorithms specifically tailored to operate within a BGP real-time collecting environment. The proposed technique exploits the high degree of repetitiveness characterizing BGP data and reduces the ICE memory usage by as much as 30%
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