1,721,065 research outputs found
A primer on statistically validated networks
No full textIn this contribution we discuss some approaches of network analysis providing information about single links or single nodes with respect to a null hypothesis taking into account the heterogeneity of the system empirically observed. With this approach, a selection of nodes and links is feasible when the null hypothesis is statistically rejected. We focus our discussion on approaches using i) the so-called disparity filter and ii) statistically validated network in bipartite networks. For both methods we discuss the importance of using multiple hypothesis test correction. Specific applications of statistically validated networks are discussed. We also discuss how statistically validated networks can be used to i) pre-process large sets of data and ii) detect cores of communities that are forming the most close-knit and stable subsets of clusters of nodes present in a complex system
Preface
No full textThe Enrico Fermi Schools are a highly prestigious series of summer schools of the Italian Physical Society with a tradition of more than 60 years and with many Nobel laureates as lecturers (https://www.sif.it/attivita/scuola_fermi/). The International Schools devote special care in planning the program and produces proceedings of the school that have become classics.
Recently an increasing number of interdisciplinary topics have been selected and our school fits into this trend. Our school will consider complex systems of social and economic origin by teaching and discussing concepts and topics of computational social science and econophysics. These are fields, where physicists, computer scientists, sociologists and economists join efforts to understand the laws governing the complex system of human interactions
Exploring the landscape of dismantling strategies based on the community structure of networks
Full text linkNetwork dismantling is a relevant research area in network science, gathering attention both from a theoretical and an operational point of view. Here, we propose a general framework for dismantling that prioritizes the removal of nodes that bridge together different network communities. The strategies we detect are not unique, as they depend on the specific realization of the community detection algorithm considered. However, when applying the methodology to some synthetic benchmark and real-world networks we find that the dismantling performances are strongly robust, and do not depend on the specific algorithm. Thus, the stochasticity inherently present in many community detection algorithms allows to identify several strategies that have comparable effectiveness but require the removal of distinct subsets of nodes. This feature is highly relevant in operational contexts in which the removal of nodes is costly and allows to identify the least expensive strategy that still holds high effectiveness
Using network community detection to investigate psychological and social features of individuals condemned for mafia crimes
No full textObjective: Only few studies have investigated social and personality characteristics of members of Italian organized criminal groups: Mafia, Camorra, ‘Ndrangheta, and Sacra Corona Unita. This study aimed to explore the most relevant social and clinical features of Mafia criminals and their psychopathic traits. Method: The Psychopathy Check List-Revised (PCL-R) and a socio-demographic questionnaire were administered to 30 condemned for Mafia crimes and imprisoned in the “Pagliarelli” district prison of Palermo (Italy). The results were investigated applying the methods of Network Theory. Results: The study identified two communities, which were statistically different in terms of history of juvenile delinquency, levels of education, and antisocial and deviant behaviours score at PCL-R. Conclusions: The onset of antisocial behaviour and educational achievement might be relevant variables in understanding mafia offences, as well as antisocial behaviours in general. Moreover, methodologies of Network Theory may be used to characterize real-world complex systems of sociological and clinical dates
Anagraphical relationships and crime specialization within Cosa Nostra
Full text linkThe aim of the present work is to investigate the relationships established within Cosa Nostra, by making use of networks and complex-systems methods. The analysis is performed at three different levels, that is, individuals, groups within mafia syndicates, and relationships amongst mafia syndicates. The reported empirical analysis is based on the criminal records of 632 affiliates to Cosa Nostra selected from a set of 125 judgements emitted by the Palermo courts from 2000 to 2014. According to the criminal records of the Palermo Prosecutor Office, such a dataset includes approximately 10% of the whole population of Cosa Nostra affiliates in western Sicily. Furthermore, the vital statistics of 235 subjects sentenced for mafia crimes and the one of their relatives complemented the database that, overall, includes about 4000 subjects. Our results show that mafia syndicates are not specialized in terms of criminal activity, rather they show a strong territorial attachment and are involved in heterogeneous criminal activities. Since syndicates insist on a delimited territory, young affiliates are selected on a territorial basis according to the significance and variety of their past criminal activity. Once inside a syndicate, affiliates tend to specialize in a few criminal activities, depending on their attitudes and the needs of the organization. Finally, despite the fact that the vast majority of mafia affiliates are males, our results highlight that female subjects are crucial to form and consolidate alliances between mafia syndicates through suitable marriages
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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