Search results for "centrality"
showing 10 items of 164 documents
Gender differences in bicycle sharing system usage in the city of Valencia
2021
Abstract Bicycle sharing systems (BSS) in cities are an environmentally friendly alternative to fossil-fuel-based transport. Among the different factors that influence its use, the scientific literature points out that there are gender differences in the frequency of trips made. The present study analysed the movements of men and women who use the BSS in the city of Valencia during weekdays. Our database contained a total of 5,300,328 trips by users over a period of 4 years. Ridership networks were constructed through user's trips (arcs) between the bicycle exchange stations (nodes). Different parameters of centrality and density of the generated networks were calculated, and the Voronoi sp…
Prevention of Violence against Children and Psychosocial Models of Intervention: Network Analysis of an Inter-Institutional Service
2014
This study describes an Italian service, the Inter-institutional Groups Operating against child Abuse and Maltreatment (GOIAM), which specializes in the treatment of child abuse. The GOIAM service is composed of 53 professionals divided into four different categories: social workers, psychologists, child neuropsychiatrists, and psychopedagogists. With the aim of detecting strengths and weaknesses of the operative model adopted by GOIAM, the whole service was analyzed through the application of social network analysis (SNA). The analysis revealed a low-density network, while the study of centrality yielded different distributions of power indicators (degree, closeness, and betweenness): pres…
The Whole Is Greater than the Sum of the Parts: A Multilayer Approach on Criminal Networks
2022
Traditional social network analysis can be generalized to model some networked systems by multilayer structures where the individual nodes develop relationships in multiple layers. A multilayer network is called multiplex if each layer shares at least one node with some other layer. In this paper, we built a unique criminal multiplex network from the pre-trial detention order by the Preliminary Investigation Judge of the Court of Messina (Sicily) issued at the end of the Montagna anti-mafia operation in 2007. Montagna focused on two families who infiltrated several economic activities through a cartel of entrepreneurs close to the Sicilian Mafia. Our network possesses three layers which sha…
Community-based Immunization Strategies for Epidemic Control
2014
Understanding the epidemic dynamics, and finding out efficient techniques to control it, is a challenging issue. A lot of research has been done on targeted immunization strategies, exploiting various global network topological properties. However, in practice, information about the global structure of the contact network may not be available. Therefore, immunization strategies that can deal with a limited knowledge of the network structure are required. In this paper, we propose targeted immunization strategies that require information only at the community level. Results of our investigations on the SIR epidemiological model, using a realistic synthetic benchmark with controlled community…
Impact of centrality on cooperative processes
2016
The solution of today's complex problems requires the grouping of task forces whose members are usually connected remotely over long physical distances and different time zones. Hence, understanding the effects of imposed communication patterns (i.e., who can communicate with whom) on group performance is important. Here, we use an agent-based model to explore the influence of the betweenness centrality of the nodes on the time the group requires to find the global maxima of NK-fitness landscapes. The agents cooperate by broadcasting messages, informing on their fitness to their neighbors, and use this information to copy the more successful agents in their neighborhood. We find that for ea…
Correlations among Game of Thieves and other centrality measures in complex networks
2021
Social Network Analysis (SNA) is used to study the exchange of resources among individuals, groups, or organizations. The role of individuals or connections in a network is described by a set of centrality metrics which represent one of the most important results of SNA. Degree, closeness, betweenness and clustering coefficient are the most used centrality measures. Their use is, however, severely hampered by their computation cost. This issue can be overcome by an algorithm called Game of Thieves (GoT). Thanks to this new algorithm, we can compute the importance of all elements in a network (i.e. vertices and edges), compared to the total number of vertices. This calculation is done not in…
Political patterning of urban namescapes and post-socialist toponymic change: A quantitative analysis of three Romanian cities
2020
Abstract Critical scholars of place-name studies have compellingly demonstrated that significant transformations in a society's namescape follow suit major power shifts and regime changes. However, despite the wealth of particular case studies existing in the literature, scarce efforts have been made to examine street name changes in a comparative framework using statistical modeling techniques of multivariate analysis. This paper aims to overcome these shortcomings by developing a comparative approach to analyzing post-socialist street-naming transformations in three Romanian cities from Transylvania (Brașov, Cluj-Napoca, and Sibiu). Based on comprehensive data collected from multiple sour…
Against cyber-utopianism. Utopian discourse "versus" sociological analysis of the transition to the digital paradigm of the cultural sphere
2015
La cultura ha dejado de ser la esfera social que iluminaba la modernidad. A pesar de su mayor centralidad social y económica propia de la sociedad postfordista, las transformaciones económicas y tecnológicas de los últimos años están cuestionando su propia existencia como esfera autónoma. En este contexto, el discurso ciberutopismo hace una lectura totalmente positiva de estas transformaciones como un empoderamiento del consumidor o del surgimientos de nuevas cadenas de cooperación creativa. Frente a este discurso ideológicamente cargado, es necesaria una ruptura epistemológica y una construcción de un programa de investigación desde la sociología de las artes y la cultura, que evalúe de fo…
A Distribution-Free Two-Sample Equivalence Test Allowing for Tied Observations
1999
A new testing procedure is derived which enables to assess the equivalence of two arbitrary noncontinuous distribution functions from which unrelated samples are taken as the data to be analyzed. The equivalence region is defined to consist of all pairs (F, G) of distribution functions such that for independent X ∼F, Y ∼G the conditional probability of {X > Y} given {X ¬= Y} lies in some short interval around 1/2. The test rejects the null hypothesis of nonequivalence if and only if the standardized distance between the U-statistics estimator of P|X > Y | X ¬= Y] and the center of the equivalence interval (1/2 - e 1 , 1/2 + e 2 ) does not exceed a critical upper bound which has to be comput…
M-Centrality: identifying key nodes based on global position and local degree variation
2023
Identifying influential nodes in a network is a major issue due to the great deal of applications concerned, such as disease spreading and rumor dynamics. That is why, a plethora of centrality measures has emerged over the years in order to rank nodes according to their topological importance in the network. Local metrics such as degree centrality make use of a very limited information and are easy to compute. Global metrics such as betweenness centrality exploit the information of the whole network structure at the cost of a very high computational complexity. Recent works have shown that combining multiple metrics is a promising strategy to quantify the node's influential ability. Our wor…