| 1. |
- Blöcker, Christopher, et al.
(författare)
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Map equation centrality: community-aware centrality based on the map equation
- 2022
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Ingår i: Applied Network Science. - : Springer. - 2364-8228. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- To measure node importance, network scientists employ centrality scores that typically take a microscopic or macroscopic perspective, relying on node features or global network structure. However, traditional centrality measures such as degree centrality, betweenness centrality, or PageRank neglect the community structure found in real-world networks. To study node importance based on network flows from a mesoscopic perspective, we analytically derive a community-aware information-theoretic centrality score based on network flow and the coding principles behind the map equation: map equation centrality. Map equation centrality measures how much further we can compress the network's modular description by not coding for random walker transitions to the respective node, using an adapted coding scheme and determining node importance from a network flow-based point of view. The information-theoretic centrality measure can be determined from a node's local network context alone because changes to the coding scheme only affect other nodes in the same module. Map equation centrality is agnostic to the chosen network flow model and allows researchers to select the model that best reflects the dynamics of the process under study. Applied to synthetic networks, we highlight how our approach enables a more fine-grained differentiation between nodes than node-local or network-global measures. Predicting influential nodes for two different dynamical processes on real-world networks with traditional and other community-aware centrality measures, we find that activating nodes based on map equation centrality scores tends to create the largest cascades in a linear threshold model.
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| 2. |
- Garrido-Skurkowicz, Natalia, et al.
(författare)
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Networked solidarity economy : Gender in interorganizational networks. An evaluation with ERGMs
- 2022
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Ingår i: Applied Network Science. - London, United Kingdom : Springer Nature. - 2364-8228. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- For their economic success, organizations in the social economy are particularly dependent on access to collective resources through interorganizational networks. Because self-organised network governance of an economy is notoriously intransparent, there is the danger that existing societal inequalities get replicated particularly well. This creates a tension with the equality-promoting mission of these organizations. This paper investigates the degree to which the goal of gender equality has been realized in the social economy of Barcelona. By analysing networks of advice-seeking and economic collaboration with exponential random graph models, network mechanisms are analysed to estimate gender-based inequality.
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| 3. |
- Holme, Petter, et al.
(författare)
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Networks of climate change : connecting causes and consequences
- 2023
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Ingår i: Applied Network Science. - : Springer Science and Business Media LLC. - 2364-8228. ; 8
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Forskningsöversikt (refereegranskat)abstract
- Understanding the causes and consequences of, and devising countermeasures to, global warming is a profoundly complex problem. Network representations are sometimes the only way forward, and sometimes able to reduce the complexity of the original problem. Networks are both necessary and natural elements of climate science. Furthermore, networks form a mathematical foundation for a multitude of computational and analytical techniques. We are only beginning to see the benefits of this connection between the sciences of climate change and network science. In this review, we cover the wide spectrum of network applications in the climate-change literature—what they represent, how they are analyzed, and what insights they bring. We also discuss network data, tools, and problems yet to be explored.
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| 4. |
- Holmgren, Anton, et al.
(författare)
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Mapping change in higher-order networks with multilevel and overlapping communities
- 2023
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Ingår i: Applied Network Science (ANS). - : Springer Nature. - 2364-8228. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- New network models of complex systems use layers, state nodes, or hyperedges to capture higher-order interactions and dynamics. Simplifying how the higher-order networks change over time or depending on the network model would be easy with alluvial diagrams, which visualize community splits and merges between networks. However, alluvial diagrams were developed for networks with regular nodes assigned to non-overlapping flat communities. How should they be defined for nodes in layers, state nodes, or hyperedges? How can they depict multilevel, overlapping communities? Here we generalize alluvial diagrams to map change in higher-order networks and provide an interactive tool for anyone to generate alluvial diagrams. We use the alluvial diagram generator in three case studies to illustrate significant changes in the organization of science, the effect of modeling network flows with memory in a citation network and distinguishing multidisciplinary from field-specific journals, and the effects of multilayer representation of a collaboration hypergraph.
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| 5. |
- Kaveh, Amin, et al.
(författare)
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Probabilistic network sparsification with ego betweenness
- 2021
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Ingår i: Applied Network Science. - : Springer Nature. - 2364-8228. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Sparsification is the process of decreasing the number of edges in a network while one or more topological properties are preserved. For probabilistic networks, sparsification has only been studied to preserve the expected degree of the nodes. In this work we introduce a sparsification method to preserve ego betweenness. Moreover, we study the effect of backboning and density on the resulting sparsified networks. Our experimental results show that the sparsification of high density networks can be used to efficiently and accurately estimate measures from the original network, with the choice of backboning algorithm only partially affecting the result.
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| 6. |
- Kriege, Nils M., et al.
(författare)
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A survey on graph kernels
- 2020
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Ingår i: Applied Network Science. - : Springer Science and Business Media LLC. - 2364-8228. ; 5:1
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Forskningsöversikt (refereegranskat)abstract
- Graph kernels have become an established and widely-used technique for solving classification tasks on graphs. This survey gives a comprehensive overview of techniques for kernel-based graph classification developed in the past 15 years. We describe and categorize graph kernels based on properties inherent to their design, such as the nature of their extracted graph features, their method of computation and their applicability to problems in practice. In an extensive experimental evaluation, we study the classification accuracy of a large suite of graph kernels on established benchmarks as well as new datasets. We compare the performance of popular kernels with several baseline methods and study the effect of applying a Gaussian RBF kernel to the metric induced by a graph kernel. In doing so, we find that simple baselines become competitive after this transformation on some datasets. Moreover, we study the extent to which existing graph kernels agree in their predictions (and prediction errors) and obtain a data-driven categorization of kernels as result. Finally, based on our experimental results, we derive a practitioner’s guide to kernel-based graph classification.
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| 7. |
- Lőrincz, László, et al.
(författare)
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Global connections and the structure of skills in local co-worker networks
- 2020
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Ingår i: Applied Network Science. - : Springer. - 2364-8228. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Social connections that reach distant places are advantageous for individuals, firms and cities, providing access to new skills and knowledge. However, systematic evidence on how firms build global knowledge access is still lacking. In this paper, we analyse how global work connections relate to differences in the skill composition of employees within companies and local industry clusters. We gather survey data from 10% of workers in a local industry in Sweden, and complement this with digital trace data to map co-worker networks and skill composition. This unique combination of data and features allows us to quantify global connections of employees and measure the degree of skill similarity and skill relatedness to co-workers. We find that workers with extensive local networks typically have skills related to those of others in the region and to those of their co-workers. Workers with more global ties typically bring in less related skills to the region. These results provide new insights into the composition of skills within knowledge-intensive firms by connecting the geography of network contacts to the diversity of skills accessible through them.
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| 8. |
- Michaud, Jérôme, Dr, 1984-, et al.
(författare)
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A spatial analysis of parliamentary elections in Sweden 1985-2018
- 2021
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Ingår i: Applied Network Science. - : Springer Nature. - 2364-8228. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding where and why political change is happening in a country is a fundamental issue in political geography. While electoral choice is individual, it is influenced by various sociological, cultural, and geographical factors postulated to create 'cultural fields' influencing individual decision-making. Here, we test the cultural field hypothesis on Sweden, an important democracy of Europe long regarded as an example by other European countries, by studying the middle-long-term evolution of the spatial structure of political choice over the last three decades. In testing the cultural field hypothesis, an analysis of spatial correlations is combined with groupings of Swedish municipalities into larger communities reflecting the similarity of their voting profiles. We show that spatial correlations decay logarithmically, which is a sign of long-ranged interactions, and also demonstrate that Sweden can be divided into three or four large and stable politico-cultural communities. More precisely, a transition from three to four main politico-cultural communities is observed. The fourth community, which emerged in the early 2000s is of particular interest as it is characterized by a large vote-share for the Sweden Democrats, while almost all other parties underperform. Moreover, the Swedish electoral landscape seems to be increasingly fragmenting even when the voting profiles of the municipalities over the country are slowly converging.
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| 9. |
- Mondani, Hernan, 1985-
(författare)
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The evolving network of labor flows in the Stockholm Region : Sector dynamics, connectivity and stability
- 2017
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Ingår i: Applied Network Science. - : Springer Science and Business Media LLC. - 2364-8228. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary theories of organizational change aim at finding processes that introduce structural variations in organizational variables and the conditions under which they can survive and be reproduced. However, the theory is limited by the lack of knowledge on interactions between organizations and the stability of interaction patterns over time. In this study, we use the network of interorganizational labor flows and tools and concepts from network science to inform the study of organizational evolution at the level of sector dynamics, in particular along the dimensions of connectivity and stability of labor flow patterns. We use a unique Swedish longitudinal register on employment in the Stockholm Region from 1990 to 2003. We find that the network is characterized by positive sector assortativity, and the public sector is relatively more tightly connected than the private one. A stability analysis shows that public organizations survive longer time in the dataset, and movements within publicly-owned organizations are the most stable while movements within the private sector are least stable. A network backbone overlap analysis shows that movements within the public sector are structurally stable over larger periods, while the ones within the private sector change quickly after a few years. We also find that the distributions for degree, interorganizational flows and betweenness centrality are highly skewed and “fat”-tailed; the public sector consistently has fatter tails than the private sector in all distributions. Implications for our understanding of how publicly and privately owned organizations are connected and react to external shocks are discussed.
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| 10. |
- Neuman, Magnus, et al.
(författare)
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Cross-validation of correlation networks using modular structure
- 2022
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Ingår i: Applied Network Science (ANS). - : Springer Science and Business Media LLC. - 2364-8228. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Correlation networks derived from multivariate data appear in many applications across the sciences. These networks are usually dense and require sparsification to detect meaningful structure. However, current methods for sparsifying correlation networks struggle with balancing overfitting and underfitting. We propose a module-based cross-validation procedure to threshold these networks, making modular structure an integral part of the thresholding. We illustrate our approach using synthetic and real data and find that its ability to recover a planted partition has a step-like dependence on the number of data samples. The reward for sampling more varies non-linearly with the number of samples, with minimal gains after a critical point. A comparison with the well-established WGCNA method shows that our approach allows for revealing more modular structure in the data used here.
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