| 1. |
- Bothorel, Cecile, et al.
(författare)
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Clustering attributed graphs : models, measures and methods
- 2015
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Ingår i: Network Science. - : Cambridge University Press (CUP). - 2050-1242 .- 2050-1250. ; 3:3, s. 408-444
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Tidskriftsartikel (refereegranskat)abstract
- Clustering a graph, i.e., assigning its nodes to groups, is an important operation whose best known application is the discovery of communities in social networks. Graph clustering and community detection have traditionally focused on graphs without attributes, with the notable exception of edge weights. However, these models only provide a partial representation of real social systems, that are thus often described using node attributes, representing features of the actors, and edge attributes, representing different kinds of relationships among them. We refer to these models as attributed graphs. Consequently, existing graph clustering methods have been recently extended to deal with node and edge attributes. This article is a literature survey on this topic, organizing, and presenting recent research results in a uniform way, characterizing the main existing clustering methods and highlighting their conceptual differences. We also cover the important topic of clustering evaluation and identify current open problems.
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| 2. |
- Cohen-Cole, Ethan, et al.
(författare)
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Static and dynamic networks in interbank markets
- 2015
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Ingår i: Network Science. - : Cambridge University Press (CUP). - 2050-1242 .- 2050-1250. ; 3:01, s. 98-123
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a model of network interactions in the interbank market. Our innovation is to model systemic risk in the interbank network as the propagation of incentives or strategic behavior rather than the propagation of losses after default. Transmission in our model is not based on default. Instead, we explain bank profitability based on competition incentives and the outcome of a strategic game. As competitors' lending decisions change, banks adjust their own decisions as a result: generating a “transmission” of shocks through the system. We provide a unique equilibrium characterization of a static model, and embed this model into a full dynamic model of network formation. We also determine the key bank, which is the bank that is crucial for the stability of the financial network.
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| 3. |
- Frank, Ove, et al.
(författare)
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Random multigraphs and aggregated triads with fixed degrees
- 2018
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Ingår i: Network Science. - : Cambridge University Press (CUP). - 2050-1242 .- 2050-1250. ; 6:2, s. 232-250
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Tidskriftsartikel (refereegranskat)abstract
- Random multigraphs with fixed degrees are obtained by the configuration model or by so called random stub matching. New combinatorial results are given for the global probability distribution of edge multiplicities and its marginal local distributions of loops and edges. The number of multigraphs on triads is determined for arbitrary degrees, and aggregated triads are shown to be useful for analyzing regular and almost regular multigraphs. Relationships between entropy and complexity are given and numerically illustrated for multigraphs with different number of vertices and specified average and variance for the degrees.
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| 4. |
- Hooijsma, Marianne, et al.
(författare)
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Multidimensional similarity in multiplex networks: friendships between same- and cross-gender bullies and same- and cross-gender victims
- 2020
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Ingår i: Network Science. - : Cambridge University Press. - 2050-1242 .- 2050-1250. ; 8:1, s. 79-96
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Tidskriftsartikel (refereegranskat)abstract
- Similar peers are more likely to become friends, but it remains unclear how the combination of multiple characteristics, known as multidimensional similarity, influences friendships. This study aimed to investigate whether similarity in gender (attribute) and bullying or victimization (network position) contributes to friendships. The school-level networks of friendships and victim-bully relationships in 17 Dutch elementary schools (2,130 students) were examined using multiplex longitudinal social network models (RSiena). The results showed that friendships were more likely to occur between same-gender peers and between bullies sharing their targets of victimization. Multidimensional similarity (similarities in gender as well as bullying) increased the likelihood of friendships for same-gender bullies targeting the same victims, but not for same-gender victims sharing bullies. The findings underline the importance of unraveling the interplay between different dimensions of similarity for children’s relationships and surpass unidimensional similarity based on single attributes.
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| 5. |
- Labun, Alona, et al.
(författare)
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The Co-evolution of Power and Friendship Networks in an Organization
- 2016
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Ingår i: Network Science. - : Cambridge University Press. - 2050-1242 .- 2050-1250. ; 4:3, s. 364-384
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Tidskriftsartikel (refereegranskat)abstract
- Despite the pivotal role that both power and interpersonal trust play in a multitude of social exchange situations, relatively little is known about their interplay. Moreover, previous theorizing makes competing claims. Do we consider our relatively more powerful exchange partners to be less trustworthy, as rational choice reasoning would suggest? Or do more complex psychological mechanisms lead us to trust them more, as motivated cognition reasoning implies? Extending the latter approach, we develop and empirically test three hypotheses on the interrelation between perceptions of interpersonal trust and power. According to the status value hypothesis, individuals are more likely to befriend those whom they or others perceive as powerful. The status signaling hypothesis states that the friends of people one perceives as powerful will also be seen as powerful. According to the self-monitoring hypothesis, high self-monitors are more likely than low self-monitors to befriend those they or others perceive as powerful. We use multiplex stochastic actor-based models to analyze the co-evolution of trust and power relations among n=49 employees in a Dutch Youth Care organization. Data covers three waves of a longitudinal sociometric network survey collected over a period of 18 months in the years 2009–2010. In general, we find some support for all three hypotheses, though the effects are weak. Being one of the first organizational field studies on the co-evolution of power and trust, we conclude with discussing the implications of these findings for the study of social exchange processes.
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| 6. |
- Magnani, Matteo, et al.
(författare)
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Introduction to the special issue on multilayer networks
- 2017
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Ingår i: NETWORK SCIENCE. - : CAMBRIDGE UNIV PRESS. - 2050-1242 .- 2050-1250. ; 5:2, s. 141-143
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- During the last century, networks of several types have been used to model a wide range of physical, biological and social systems. For example, Moreno (1934) studied social networks with multiple types of ties, later called multiplex networks (Verbrugge, 1979; Minor, 1983; Lazega & Pattison, 1999) as well as networks with multiple types of actors. Networks with multiple types of actors and relational ties have often been used together: relevant examples are the extensions of two-mode networks studied by Wasserman & Iacobucci (1991), multi-level networks (Lazega & Snijders, 2016), and heterogeneous information networks (Sun et al., 2012). More recently, researchers in physics and computer science have developed models for different types of interconnected networks known as networks of networks (Buldyrev et al., 2010; D'Agostino & Scala, 2014), multilayer social networks (Magnani & Rossi, 2011), and interconnected networks (Dickison et al., 2012).
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| 7. |
- Maya-Jariego, Isidro, et al.
(författare)
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Personal networks and psychological attributes: Exploring individual differences in personality and sense of community and their relationship to the structure of personal networks
- 2020
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Ingår i: NETWORK SCIENCE. - : CAMBRIDGE UNIV PRESS. - 2050-1242 .- 2050-1250. ; 8:2, s. 168-188
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Tidskriftsartikel (refereegranskat)abstract
- The paper explores the relationship between personality characteristics, sense of community and the structure of personal networks. We collected personal network data from 100 adults, consisting of the information about their 45 alters and ties among them. In addition to the typically used bivariate correlations to analyze the relationship between individual psychological differences and network structure, we propose first the use of typologies of networks and personality and second modified versions of the triadic census in ego-networks. The results show that different personality types tend to occupy a different kind of networks and that newly introduced triadic measures show a relatively higher association with examined psychological attributes than global network measures. Overall, the Psychological Sense of Community showed higher associations with network measures than Big Five personality traits. The former was positively correlated with measures of closed triads among alters, but also with alters embedded in triads with weak ties. Regarding personality traits, Emotional Stability was positively correlated with strong closed triads and with the overall indicator of density. The elaboration of typologies and the census of triads are shown to be effective strategies for the description of personal networks, as well as for the analysis of individual psychological differences.
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| 8. |
- Nordlund, Carl
(författare)
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Power-relational core-periphery structures : Peripheral dependency and core dominance in binary and valued networks
- 2018
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Ingår i: Network Science. - : Cambridge University Press (CUP). - 2050-1242 .- 2050-1250. ; 6:3, s. 348-369
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Forskningsöversikt (refereegranskat)abstract
- With origins in post-war development thinking, the core-periphery concept has spread across the social and, increasingly, the natural sciences. Initially reflecting divergent socioeconomic properties of geographical regions, its relational connotations rapidly led to more topological interpretations. In today's network science, the standard core-periphery model consists of a cohesive set of core actors and a peripheral set of internally disconnected actors. Exploring the classical core-periphery literature, this paper finds conceptual support for the characteristic intra-categorical density differential. However, this literature also lends support to the notions of peripheral dependency and core dominance, power-relational aspects that existing approaches do not capture. To capture such power-relations, this paper suggests extensions to the correlation-based core-periphery metric of Borgatti and Everett (2000). Capturing peripheral dependency and, optionally, core dominance, these extensions allow for either measuring the degree of such power-relational features in given core-periphery partitions, or as part of a criteria function to search for power-relational core-periphery structures. Applied to the binary and valued citation data in Borgatti and Everett (2000), the proposed extensions seemingly capture dependency and dominance features of core-periphery structures. This is particularly evident when, circling back to the original domains of the concept, examining the network of European commodity trade in 2010.
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| 9. |
- Spricer, Kristoffer, et al.
(författare)
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An SIR epidemic on a weighted network
- 2019
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Ingår i: Network science. - : Cambridge University Press (CUP). - 2050-1242 .- 2050-1250. ; 7:4, s. 556-580
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Tidskriftsartikel (refereegranskat)abstract
- We introduce a weighted configuration model graph, where edge weights correspond to the probability of infection in an epidemic on the graph. On these graphs, we study the development of a Susceptible-Infectious-Recovered epidemic using both Reed-Frost and Markovian settings. For the special case of having two different edge types, we determine the basic reproduction number R-0, the probability of a major outbreak, and the relative final size of a major outbreak. Results are compared with those for a calibrated unweighted graph. The degree distributions are based on both theoretical constructs and empirical network data. In addition, bivariate standard normal copulas are used to model the dependence between the degrees of the two edge types, allowing for modeling the correlation between edge types over a wide range. Among the results are that the weighted graph produces much richer results than the unweighted graph. Also, while R-0 always increases with increasing correlation between the two degrees, this is not necessarily true for the probability of a major outbreak nor for the relative final size of a major outbreak. When using copulas we see that these can produce results that are similar to those of the empirical degree distributions, indicating that in some cases a copula is a viable alternative to using the full empirical data.
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