1,721,291 research outputs found
Layouts for mobility management in wireless ATM networks
No full textAbstractIn this paper, we present a new model that combines quality of service and mobility aspects in wireless ATM networks. Namely, besides the hop count and load parameters of the basic ATM layouts, we introduce a new notion of distance that estimates the time needed to reconstruct the virtual channel of a wireless user when he moves through the network. Quality of service guarantee dictates that the rerouting phase must be imperceptible, that is, the maximum distance between two virtual channels must be maintained as low as possible. Therefore, a natural combinatorial problem arises in which suitable trade-offs must be determined between the different performance measures. We first show that establishing the existence of a layout with maximum hop count h, load l and distance d is NP-complete, even in the very restricted case h=2, l=1 and d=1. We then provide optimal layout constructions for basic interconnection networks, such as chains and rings
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
Appropriate 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
Nella Spirale del Clima culture e società mediterranee di fronte ai mutamenti climatici.
No full textQuesto libro è nato da uno scambio di osservazioni e di suggestioni “lanciate” fra due versanti, quello storico e quello scientifico, all’inizio quasi un gioco di idee. È cominciato così un viaggio nel tempo, seguendo il filo rosso del clima. Mutamenti climatici e previsioni del tempo non sono problemi solo di oggi: da alcuni millenni le civiltà mediterranee si sono interrogate sul clima e sul suo rapporto con le attività umane, su come prevedere il tempo e difendersi dagli eventi estremi. Cosa pensavano gli antichi dei cambiamenti climatici che li avevano preceduti, di cui tramandano ricordi e riflessioni? In che modo le teorie sulla forma della Terra e le sue rappresentazioni influivano sulla conoscenza dei climi terrestri? Le modificazioni ambientali indotte dalle attività umane del passato potevano influire sul clima? E ancora: come sono stati superati in passato i periodi caldi e quelli freddi, fino al riscaldamento globale attuale? Da pochi anni è aumentata la sensibilità a questi temi e, benché per l’area del Mediterraneo rimanga ancora molto lavoro da fare, questo libro vuole aprire qualche spiraglio sulla storia delle risposte umane ai cambiamenti climatici e agli eventi estremi. La fatica di adattarsi alle variazioni, di subire le bizzarrie del tempo, con i danni e i rischi che ciò ha sempre comportato, non riguarda solo la storia contemporanea. Una riflessione sul passato per comprendere meglio la grande sfida ambientale che ci attende
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