1,720,968 research outputs found
Synecology of Quercus suber communities in S-Europe along geographical and ecological gradients.European Vegetation Survey, March 2005,Roma
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Vote for me! Election control via social influence in arbitrary scoring rule voting systems
No full textOnline social networks are used to diffuse opinions and ideas among users, enabling a faster communication and a wider audience. The way in which opinions are conditioned by social interactions is usually called social influence. Social influence is extensively used during political campaigns to advertise and support candidates. We consider the problem of exploiting social influence in a network of voters to change their opinion about a target candidate with the aim of increasing his chance to win or lose the election in a wide range of voting systems. We introduce the Linear Threshold Ranking, a natural and powerful extension of the well-established Linear Threshold Model, which describes the change of opinions taking into account the amount of exercised influence. We are able to maximize the score of a target candidate up to a factor of 1-1/e by showing submodularity. We exploit such property to provide a 1/3(1 - l/e)-approximation algorithm for the constructive election control problem and a 1/2(1 - l/e)-approximation algorithm for the destructive control problem. The algorithm can be used in arbitrary scoring rule voting systems, including plurality rule and borda count
Analisi fitogeografica quantitativa della distribuzione dei valori del patrimonio botanico nella regione laziale
No full textEnvironmental heterogeneity and species composition in different communities of mesic deciduous oak forest in Central-Southern Italy
No full textTemperate deciduous forests with Balkano-Apenninic affinities: floristic changes and heterogeneity.European Vegetation Survey,15-20 Aprile 2004
No full textExploiting social influence to control elections based on positional scoring rules
No full textHerein, we present Linear Threshold Ranking (LTR), an extension of the Linear Threshold Model (Kempe et al., KDD 2003). LTR models the spread of a message supporting a target candidate in a social network and how social influence affects the preferences of the voters who receive it, in elections based on positional scoring rules. The problem of election control through social influence requires finding a bounded subset of nodes to be the initial spreaders of this message to maximize the Margin of Victory of a target candidate against the most voted opponent. We prove the problem is NP-hard in LTR. By showing the equivalence of LTR with alternative stochastic processes and then exploiting submodularity, we provide a [Formula presented] approximation algorithm. We achieve similar results also in the destructive variation of LTR, where the message undermines a target candidate, negatively influencing the voters' preference on that candidate
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
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