1,720,968 research outputs found
L’evoluzione delle tecniche di ingegneria sociale e il loro utilizzo negli attacchi contro gli utenti di servizi di pagamento online
No full textLa recente pandemia ha catalizzato il già rapido processo di trasformazione digitale che da tempo coinvolge tanto la sfera privata quanto quella lavorativa dei cittadini dei principali Paesi industrializzati. Se da un lato la digitalizzazione ha rappresentato una enorme opportunità di sviluppo, in alcuni casi la rapidità di questo fenomeno ha reso evidenti nuove vulnerabilità di tipo tecnologico, procedurale, psicologico e sociale. Lo scenario della minaccia cyber è evoluto conseguentemente: i threat actor hanno colto le nuove opportunità affinando le tecniche, tattiche e procedure d’attacco (TTP), rendendole più efficaci per il perseguimento dei propri interessi. In questo frangente si osserva, in particolare contro il settore finanziario, un’ampia diffusione di tecniche avanzate di ingegneria sociale (dall’inglese social engineering), in sinergia con l’uso malevolo di piattaforme e artefatti digitali.
La diffusione di un’adeguata consapevolezza sull’evoluzione di questa minaccia a livello individuale, professionale e collettivo rappresenta il principale fattore di contrasto. A tal fine è fondamentale sviluppare un’adeguata conoscenza (situational awareness) della minaccia cyber, attraverso attività continuative di cyber threat intelligence (CTI) e information sharing, e la conduzione di campagne di security awareness, finalizzate a trasformare l’elemento umano da vulnerabilità a sensore in grado di rilevare la componente degli attacchi cyber non individuabili attraverso i presidi di sicurezza tecnologici
Coexistence of Defect Morphologies in Three-Dimensional Active Nematics
Full text linkWe establish how active stress globally affects the morphology of disclination lines of a three-dimensional active nematic liquid crystal under chaotic flow. Thanks to a defect detection algorithm based on the local nematic orientation, we show that activity selects a crossover length scale in between the size of small defect loops and that of long and tangled defect lines of fractal dimension 2. This length scale crossover is consistent with the scaling of the average separation between defects as a function of activity. Moreover, on the basis of numerical simulation in a 3D periodic geometry, we show the presence of a network of regular defect loops, contractible onto the 3-torus, always coexisting with wrapping defect lines. While the length of regular defects scales linearly with the emerging active length scale, it verifies an inverse quadratic dependence for wrapping defects. The shorter the active length scale, the more the defect lines wrap around the periodic boundaries, resulting in extremely long and buckled structures
Phase Coexistence in Two-Dimensional Passive and Active Dumbbell Systems
Full text linkWe demonstrate that there is a macroscopic coexistence between regions with hexatic order and regions in the liquid or gas phase over a finite interval of packing fractions in active dumbbell systems with repulsive power-law interactions in two dimensions. In the passive limit, this interval remains finite, similar to what has been found in two-dimensional systems of hard and soft disks. We did not find discontinuous behavior upon increasing activity from the passive limit
Dynamics of Motility-Induced clusters: coarsening beyond Ostwald ripening
Full text linkWe study the dynamics of clusters of Active Brownian Disks generated by
Motility-Induced Phase Separation, by applying an algorithm that we devised to
track cluster trajectories. We identify an aggregation mechanism that goes
beyond Ostwald ripening but also yields . Active clusters of mass
self-propel with enhanced diffusivity Pe. Their fast
motion drives aggregation into large fractal structures, which are patchworks
of diverse hexatic orders, and coexist with regular, orientationally uniform,
smaller ones. To bring out the impact of activity, we perform a comparative
study of a passive system that evidences major differences with the active
case.Comment: 6 pages, 5 figures, S
Morphology, Polarization Patterns, Compression, and Entropy Production in Phase-Separating Active Dumbbell Systems
No full textPolar patterns and topological defects are ubiquitous in active matter. In this paper, we study a paradigmatic polar active dumbbell system through numerical simulations, to clarify how polar patterns and defects emerge and shape evolution. We focus on the interplay between these patterns and morphology, domain growth, irreversibility, and compressibility, tuned by dumbbell rigidity and interaction strength. Our results show that, when separated through MIPS, dumbbells with softer interactions can slide one relative to each other and compress more easily, producing blurred hexatic patterns, polarization patterns extended across entire hexatically varied domains, and stronger compression effects. Analysis of isolated domains reveals the consistent presence of inward-pointing topological defects that drive cluster compression and generate non-trivial density profiles, whose magnitude and extension are ruled by the rigidity of the pairwise potential. Investigation of entropy production reveals instead that clusters hosting an aster/spiral defect are characterized by a flat/increasing entropy profile mirroring the underlying polarization structure, thus suggesting an alternative avenue to distinguish topological defects on thermodynamical grounds. Overall, our study highlights how interaction strength and defect–compression interplay affect cluster evolution in particle-based active models, and also provides connections with recent studies of continuum polar active field models
Arrested phase separation and chiral symmetry breaking in active dumbbells under shear
No full textThrough molecular dynamics simulations, we investigate the phase separation and aggregation dynamics of active dumbbell particles in two dimensions subjected to shear. We find that the growth of the phase-separated region is arrested when shear is applied, with the average cluster size plateauing toward a value R_{s} that remains constant over time. While activity enhances the resilience of clusters against shear-induced breakup, R_{s} decreases with growing shear rate γ[over ̇], with an intermediate regime where R_{s}∝γ[over ̇]^{−1}. We find that clusters in the stationary state are progressively less polarized and increasingly elongated with increasing shear. At the same time, we find a breaking in chiral symmetry of both rotation direction and internal organization of clusters: Typically, dumbbells point toward the cluster center with a small nonzero angle, such that the active torque opposes the shear torque, with cluster's angular velocity well captured by a simplified analytical model. We argue that this conformation makes clusters more stable against shear
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
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