Ranking in Evolving Complex Networks

Total Page:16

File Type:pdf, Size:1020Kb

Ranking in Evolving Complex Networks View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by RERO DOC Digital Library Published in "Physics Reports doi: 10.1016/j.physrep.2017.05.001, 2017" which should be cited to refer to this work. Ranking in evolving complex networks Hao Liao a, Manuel Sebastian Mariani b,a,*, Matúš Medo c,d,b,*, Yi-Cheng Zhang b, Ming-Yang Zhou a a National Engineering Laboratory for Big Data System Computing Technology, Guangdong Province Key Laboratory of Popular High Performance Computers, College of Computer Science and Software Engineering, Shenzhen University, Shenzhen 518060, PR China b Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland c Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, PR China d Department of Radiation Oncology, Inselspital, Bern University Hospital and University of Bern, 3010 Bern, Switzerland Complex networks have emerged as a simple yet powerful framework to represent and analyze a wide range of complex systems. The problem of ranking the nodes and the edges in complex networks is critical for a broad range of real-world problems because it affects how we access online information and products, how success and talent are evaluated in human activities, and how scarce resources are allocated by companies and Keywords: policymakers, among others. This calls for a deep understanding of how existing ranking Complex networks algorithms perform, and which are their possible biases that may impair their effectiveness. Ranking Many popular ranking algorithms (such as Google’s PageRank) are static in nature and, Centrality metrics as a consequence, they exhibit important shortcomings when applied to real networks Temporal networks that rapidly evolve in time. At the same time, recent advances in the understanding and Recommendation modeling of evolving networks have enabled the development of a wide and diverse range Network science of ranking algorithms that take the temporal dimension into account. The aim of this review is to survey the existing ranking algorithms, both static and time-aware, and their applications to evolving networks. We emphasize both the impact of network evolution on well-established static algorithms and the benefits from including the temporal dimension for tasks such as prediction of network traffic, prediction of future links, and identification of significant nodes. Contents 1. Introduction............................................................................................................................................................................................... 3 2. Ranking with static centrality metrics .................................................................................................................................................... 4 2.1. Getting started: basic language of complex networks .............................................................................................................. 4 2.2. Degree and other local centrality metrics .................................................................................................................................. 4 2.2.1. Degree............................................................................................................................................................................ 4 2.2.2. H-index.......................................................................................................................................................................... 5 2.2.3. Other local centrality metrics ...................................................................................................................................... 5 2.3. Metrics based on shortest paths.................................................................................................................................................. 5 2.3.1. Closeness centrality ...................................................................................................................................................... 6 2.3.2. Betweenness centrality ................................................................................................................................................ 6 2.4. Coreness centrality and its relation with degree and H-index ................................................................................................. 6 * Corresponding authors at: Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland. E-mail addresses: [email protected] (M.S. Mariani), [email protected] (M. Medo). 1 2.5. Eigenvector-based centrality metrics ......................................................................................................................................... 7 2.5.1. Eigenvector centrality .................................................................................................................................................. 7 2.5.2. Katz centrality............................................................................................................................................................... 8 2.5.3. Win–loss scoring systems for ranking in sport........................................................................................................... 8 2.5.4. PageRank ....................................................................................................................................................................... 9 2.5.5. PageRank variants......................................................................................................................................................... 10 2.5.6. HITS algorithm .............................................................................................................................................................. 11 2.6. A case study: node centrality in the Zachary’s karate club network ........................................................................................ 11 2.7. Static ranking algorithms in bipartite networks ........................................................................................................................ 12 2.7.1. Co-HITS algorithm ........................................................................................................................................................ 13 2.7.2. Method of reflections ................................................................................................................................................... 13 2.7.3. Fitness-complexity metric ........................................................................................................................................... 13 2.8. Rating-based ranking algorithms on bipartite networks .......................................................................................................... 14 3. The impact of network evolution on static ranking algorithms ............................................................................................................ 15 3.1. The first-mover advantage in preferential attachment and its suppression............................................................................ 15 3.2. PageRank’s temporal bias and its suppression........................................................................................................................... 16 3.3. Illusion of influence in social systems ........................................................................................................................................ 18 4. Time-dependent ranking algorithms ...................................................................................................................................................... 19 4.1. Striving for time-balance: Node-based time-rescaled metrics................................................................................................. 19 4.2. Metrics with explicit penalization for older edges and/or nodes ............................................................................................. 20 4.2.1. Time-weighted degree and its use in predicting future trends................................................................................. 20 4.2.2. Penalizing old edges: Effective Contagion Matrix ...................................................................................................... 21 4.2.3. Penalizing old edges: TimedPageRank ........................................................................................................................ 21 4.2.4. Focusing on a temporal window: T-Rank, SARA ........................................................................................................ 22 4.2.5. PageRank with time-dependent teleportation: CiteRank.......................................................................................... 22 4.2.6. Time-dependent reputation algorithms ..................................................................................................................... 22 4.3. Model-based ranking of nodes .................................................................................................................................................... 23 5. Ranking nodes in temporal networks...................................................................................................................................................... 25 5.1. Getting started: how to represent a temporal network?
Recommended publications
  • Approximating Network Centrality Measures Using Node Embedding and Machine Learning
    Approximating Network Centrality Measures Using Node Embedding and Machine Learning Matheus R. F. Mendon¸ca,Andr´eM. S. Barreto, and Artur Ziviani ∗† Abstract Extracting information from real-world large networks is a key challenge nowadays. For instance, computing a node centrality may become unfeasible depending on the intended centrality due to its computational cost. One solution is to develop fast methods capable of approximating network centralities. Here, we propose an approach for efficiently approximating node centralities for large networks using Neural Networks and Graph Embedding techniques. Our proposed model, entitled Network Centrality Approximation using Graph Embedding (NCA-GE), uses the adjacency matrix of a graph and a set of features for each node (here, we use only the degree) as input and computes the approximate desired centrality rank for every node. NCA-GE has a time complexity of O(jEj), E being the set of edges of a graph, making it suitable for large networks. NCA-GE also trains pretty fast, requiring only a set of a thousand small synthetic scale-free graphs (ranging from 100 to 1000 nodes each), and it works well for different node centralities, network sizes, and topologies. Finally, we compare our approach to the state-of-the-art method that approximates centrality ranks using the degree and eigenvector centralities as input, where we show that the NCA-GE outperforms the former in a variety of scenarios. 1 Introduction Networks are present in several real-world applications spread among different disciplines, such as biology, mathematics, sociology, and computer science, just to name a few. Therefore, network analysis is a crucial tool for extracting relevant information.
    [Show full text]
  • Network Centrality) (100 Points)
    In the name of God. Sharif University of Technology Analysis of Biological Networks CE 558 Spring 2020 Dr. H.R. Rabiee Homework 3 (Network Centrality) (100 points) 1. Compute centrality of the nodes with the most and least centrality for the following network according to the following measures: • Degree • Eccentricity • Closeness • Shortest Path Betweenness 1 2. For a complete (m,n)-bipartite graph compute Katz centrality measure with α = 2mn for each node and determine which nodes have the most centrality. ( (m, n)-bipartite graph consists of two independent partitions with m and n nodes each) 3. (a) For a cycle graph prove that we don't have a central node. (The centrality of all nodes are the same). Prove it for following centrality measures. • Degree • Eccentricity • Closeness • Shortest Path Betweenness • Katz • PageRank (b) Prove that in a graph that has a full-cycle automorphism, there is no central measure. Prove it for an arbitrary centrality measure. (Note that an appropriate centrality measure only depends on the structure of the graph and not the node labels) (c) for n > 2, find a graph with n nodes that has an automorphism but the centrality of the nodes are not all equal for some measure. 1 4. Prove that for any d-regular graph, PageRank centrality measure approaches to nm CKatz as the number of steps approaches to infinity, where n is the number of nodes, m is the number of steps and CKatz is 1 the Katz centrality measure with α = d . 5. (Fast Algorithm to Calculate Shortest-Path-Betweenness Centrality Measure) Consider an arbitrary undirected graph G = (V; E).
    [Show full text]
  • Models for Networks with Consumable Resources: Applications to Smart Cities Hayato Montezuma Ushijima-Mwesigwa Clemson University, [email protected]
    Clemson University TigerPrints All Dissertations Dissertations 12-2018 Models for Networks with Consumable Resources: Applications to Smart Cities Hayato Montezuma Ushijima-Mwesigwa Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Recommended Citation Ushijima-Mwesigwa, Hayato Montezuma, "Models for Networks with Consumable Resources: Applications to Smart Cities" (2018). All Dissertations. 2284. https://tigerprints.clemson.edu/all_dissertations/2284 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. Models for Networks with Consumable Resources: Applications to Smart Cities A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Computer Science by Hayato Ushijima-Mwesigwa December 2018 Accepted by: Dr. Ilya Safro, Committee Chair Dr. Mashrur Chowdhury Dr. Brian Dean Dr. Feng Luo Abstract In this dissertation, we introduce different models for understanding and controlling the spreading dynamics of a network with a consumable resource. In particular, we consider a spreading process where a resource necessary for transit is partially consumed along the way while being refilled at special nodes on the network. Examples include fuel consumption of vehicles together with refueling stations, information loss during dissemination with error correcting nodes, consumption of ammunition of military troops while moving, and migration of wild animals in a network with a limited number of water-holes. We undertake this study from two different perspectives. First, we consider a network science perspective where we are interested in identifying the influential nodes, and estimating a nodes’ relative spreading influence in the network.
    [Show full text]
  • RESEARCH PAPER . Text Information Aggregation with Centrality Attention
    SCIENCE CHINA Information Sciences . RESEARCH PAPER . Text Information Aggregation with Centrality Attention Jingjing Gong, Hang Yan, Yining Zheng, Qipeng Guo, Xipeng Qiu* & Xuanjing Huang School of Computer Science, Fudan University, Shanghai 200433, China Shanghai Key Laboratory of Intelligent Information Processing, Fudan University, Shanghai 200433, China fjjgong, hyan11, ynzheng15, qpguo16, xpqiu, [email protected] Abstract A lot of natural language processing problems need to encode the text sequence as a fix-length vector, which usually involves aggregation process of combining the representations of all the words, such as pooling or self-attention. However, these widely used aggregation approaches did not take higher-order relationship among the words into consideration. Hence we propose a new way of obtaining aggregation weights, called eigen-centrality self-attention. More specifically, we build a fully-connected graph for all the words in a sentence, then compute the eigen-centrality as the attention score of each word. The explicit modeling of relationships as a graph is able to capture some higher-order dependency among words, which helps us achieve better results in 5 text classification tasks and one SNLI task than baseline models such as pooling, self-attention and dynamic routing. Besides, in order to compute the dominant eigenvector of the graph, we adopt power method algorithm to get the eigen-centrality measure. Moreover, we also derive an iterative approach to get the gradient for the power method process to reduce both memory consumption and computation requirement. Keywords Information Aggregation, Eigen Centrality, Text Classification, NLP, Deep Learning Citation Jingjing Gong, Hang Yan, Yining Zheng, Qipeng Guo, Xipeng Qiu, Xuanjing Huang.
    [Show full text]
  • Katz Centrality for Directed Graphs • Understand How Katz Centrality Is an Extension of Eigenvector Centrality to Learning Directed Graphs
    Prof. Ralucca Gera, [email protected] Applied Mathematics Department, ExcellenceNaval Postgraduate Through Knowledge School MA4404 Complex Networks Katz Centrality for directed graphs • Understand how Katz centrality is an extension of Eigenvector Centrality to Learning directed graphs. Outcomes • Compute Katz centrality per node. • Interpret the meaning of the values of Katz centrality. Recall: Centralities Quality: what makes a node Mathematical Description Appropriate Usage Identification important (central) Lots of one-hop connections The number of vertices that Local influence Degree from influences directly matters deg Small diameter Lots of one-hop connections The proportion of the vertices Local influence Degree centrality from relative to the size of that influences directly matters deg C the graph Small diameter |V(G)| Lots of one-hop connections A weighted degree centrality For example when the Eigenvector centrality to high centrality vertices based on the weight of the people you are (recursive formula): neighbors (instead of a weight connected to matter. ∝ of 1 as in degree centrality) Recall: Strongly connected Definition: A directed graph D = (V, E) is strongly connected if and only if, for each pair of nodes u, v ∈ V, there is a path from u to v. • The Web graph is not strongly connected since • there are pairs of nodes u and v, there is no path from u to v and from v to u. • This presents a challenge for nodes that have an in‐degree of zero Add a link from each page to v every page and give each link a small transition probability controlled by a parameter β. u Source: http://en.wikipedia.org/wiki/Directed_acyclic_graph 4 Katz Centrality • Recall that the eigenvector centrality is a weighted degree obtained from the leading eigenvector of A: A x =λx , so its entries are 1 λ Thoughts on how to adapt the above formula for directed graphs? • Katz centrality: ∑ + β, Where β is a constant initial weight given to each vertex so that vertices with zero in degree (or out degree) are included in calculations.
    [Show full text]
  • A Systematic Survey of Centrality Measures for Protein-Protein
    Ashtiani et al. BMC Systems Biology (2018) 12:80 https://doi.org/10.1186/s12918-018-0598-2 RESEARCHARTICLE Open Access A systematic survey of centrality measures for protein-protein interaction networks Minoo Ashtiani1†, Ali Salehzadeh-Yazdi2†, Zahra Razaghi-Moghadam3,4, Holger Hennig2, Olaf Wolkenhauer2, Mehdi Mirzaie5* and Mohieddin Jafari1* Abstract Background: Numerous centrality measures have been introduced to identify “central” nodes in large networks. The availability of a wide range of measures for ranking influential nodes leaves the user to decide which measure may best suit the analysis of a given network. The choice of a suitable measure is furthermore complicated by the impact of the network topology on ranking influential nodes by centrality measures. To approach this problem systematically, we examined the centrality profile of nodes of yeast protein-protein interaction networks (PPINs) in order to detect which centrality measure is succeeding in predicting influential proteins. We studied how different topological network features are reflected in a large set of commonly used centrality measures. Results: We used yeast PPINs to compare 27 common of centrality measures. The measures characterize and assort influential nodes of the networks. We applied principal component analysis (PCA) and hierarchical clustering and found that the most informative measures depend on the network’s topology. Interestingly, some measures had a high level of contribution in comparison to others in all PPINs, namely Latora closeness, Decay, Lin, Freeman closeness, Diffusion, Residual closeness and Average distance centralities. Conclusions: The choice of a suitable set of centrality measures is crucial for inferring important functional properties of a network.
    [Show full text]
  • Eigenvector Centrality and Uniform Dominant Eigenvalue of Graph Components
    Eigenvector Centrality and Uniform Dominant Eigenvalue of Graph Components Collins Anguzua,1, Christopher Engströmb,2, John Mango Mageroa,3,∗, Henry Kasumbaa,4, Sergei Silvestrovb,5, Benard Abolac,6 aDepartment of Mathematics, School of Physical Sciences, Makerere University, Box 7062, Kampala, Uganda bDivision of Applied Mathematics, The School of Education, Culture and Communication (UKK), Mälardalen University, Box 883, 721 23, Västerås,Sweden cDepartment of Mathematics, Gulu University, Box 166, Gulu, Uganda Abstract Eigenvector centrality is one of the outstanding measures of central tendency in graph theory. In this paper we consider the problem of calculating eigenvector centrality of graph partitioned into components and how this partitioning can be used. Two cases are considered; first where the a single component in the graph has the dominant eigenvalue, secondly when there are at least two components that share the dominant eigenvalue for the graph. In the first case we implement and compare the method to the usual approach (power method) for calculating eigenvector centrality while in the second case with shared dominant eigenvalues we show some theoretical and numerical results. Keywords: Eigenvector centrality, power iteration, graph, strongly connected component. ?This document is a result of the PhD program funded by Makerere-Sida Bilateral Program under Project 316 "Capacity Building in Mathematics and Its Applications". arXiv:2107.09137v1 [math.NA] 19 Jul 2021 ∗John Mango Magero Email addresses: [email protected] (Collins Anguzu), [email protected] (Christopher Engström), [email protected] (John Mango Magero), [email protected] (Henry Kasumba), [email protected] (Sergei Silvestrov), [email protected] (Benard Abola) 1PhD student in Mathematics, Makerere University.
    [Show full text]
  • An Axiom System for Feedback Centralities
    Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence (IJCAI-21) An Axiom System for Feedback Centralities Tomasz W ˛as∗ , Oskar Skibski University of Warsaw {t.was, o.skibski}@mimuw.edu.pl Abstract Centrality General axioms EC _ EM CY _ BL Eigenvector LOC ED NC EC CY In recent years, the axiomatic approach to central- Katz LOC ED NC EC BL ity measures has attracted attention in the literature. Katz prestige LOC ED NC EM CY However, most papers propose a collection of ax- PageRank LOC ED NC EM BL ioms dedicated to one or two considered centrality measures. In result, it is hard to capture the differ- Table 1: Our characterizations based on 7 axioms: Locality (LOC), ences and similarities between various measures. Edge Deletion (ED), Node Combination (NC), Edge Compensation In this paper, we propose an axiom system for four (EC), Edge Multiplication (EM), Cycle (CY) and Baseline (BL). classic feedback centralities: Eigenvector central- ity, Katz centrality, Katz prestige and PageRank. ties, while based on the same principle, differ in details which We prove that each of these four centrality mea- leads to diverse results and often opposite conclusions. sures can be uniquely characterized with a subset In recent years, the axiomatic approach has attracted at- of our axioms. Our system is the first one in the lit- tention in the literature [Boldi and Vigna, 2014; Bloch et al., erature that considers all four feedback centralities. 2016]. This approach serves as a method to build theoret- ical foundations of centrality measures and to help in mak- ing an informed choice of a measure for an application at 1 Introduction hand.
    [Show full text]
  • Utilizing the Simple Graph Convolutional Neural Network As a Model for Simulating Infuence Spread in Networks
    Mantzaris et al. Comput Soc Netw (2021) 8:12 https://doi.org/10.1186/s40649-021-00095-y RESEARCH Open Access Utilizing the simple graph convolutional neural network as a model for simulating infuence spread in networks Alexander V. Mantzaris1* , Douglas Chiodini1 and Kyle Ricketson2 *Correspondence: [email protected] Abstract 1 Department of Statistics The ability for people and organizations to connect in the digital age has allowed the and Data Science, University of Central Florida (UCF), growth of networks that cover an increasing proportion of human interactions. The 4000 Central Florida Blvd, research community investigating networks asks a range of questions such as which Orlando 32816, USA participants are most central, and which community label to apply to each mem- Full list of author information is available at the end of the ber. This paper deals with the question on how to label nodes based on the features article (attributes) they contain, and then how to model the changes in the label assignments based on the infuence they produce and receive in their networked neighborhood. The methodological approach applies the simple graph convolutional neural network in a novel setting. Primarily that it can be used not only for label classifcation, but also for modeling the spread of the infuence of nodes in the neighborhoods based on the length of the walks considered. This is done by noticing a common feature in the formulations in methods that describe information difusion which rely upon adjacency matrix powers and that of graph neural networks. Examples are provided to demonstrate the ability for this model to aggregate feature information from nodes based on a parameter regulating the range of node infuence which can simulate a process of exchanges in a manner which bypasses computationally intensive stochas- tic simulations.
    [Show full text]
  • A Graph Neural Network Deep Learning Model Of
    bioRxiv preprint doi: https://doi.org/10.1101/2021.03.15.435531; this version posted March 15, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Structure Can Predict Function in the Human Brain: A Graph Neural Network Deep Learning Model of Functional Connectivity and Centrality based on Structural Connectivity Josh Neudorf, Shaylyn Kress, and Ron Borowsky* Cognitive Neuroscience Lab, Department of Psychology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada * Corresponding author E-mail: [email protected] (RB) bioRxiv preprint doi: https://doi.org/10.1101/2021.03.15.435531; this version posted March 15, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. STRUCTURE CAN PREDICT FUNCTION IN THE HUMAN BRAIN 1 Abstract Although functional connectivity and associated graph theory measures (e.g., centrality; how centrally important to the network a region is) are widely used in brain research, the full extent to which these functional measures are related to the underlying structural connectivity is not yet fully understood. The most successful recent methods have managed to account for 36% of the variance in functional connectivity based on structural connectivity. Graph neural network deep learning methods have not yet been applied for this purpose, and offer an ideal model architecture for working with connectivity data given their ability to capture and maintain inherent network structure.
    [Show full text]
  • Hybrid Centrality Measures for Binary and Weighted Networks
    Hybrid Centrality Measures for Binary and Weighted Networks (Accepted at the 3rd workshop on Complex Networks) Alireza Abbasi, Liaquat Hossain Centre for Complex Systems Research, Faculty of Engineering and IT, University of Sydney, NSW 2006, Australia; [email protected]. Abstract Existing centrality measures for social network analysis suggest the im- portance of an actor and give consideration to actor’s given structural position in a network. These existing measures suggest specific attribute of an actor (i.e., popularity, accessibility, and brokerage behavior). In this study, we propose new hybrid centrality measures (i.e., Degree-Degree, Degree-Closeness and Degree- Betweenness), by combining existing measures (i.e., degree, closeness and bet- weenness) with a proposition to better understand the importance of actors in a given network. Generalized set of measures are also proposed for weighted net- works. Our analysis of co-authorship networks dataset suggests significant corre- lation of our proposed new centrality measures (especially weighted networks) than traditional centrality measures with performance of the scholars. Thus, they are useful measures which can be used instead of traditional measures to show prominence of the actors in a network. 1 Introduction Social network analysis (SNA) is the mapping and measuring of relationships and flows between nodes of the social network. SNA provides both a visual and a ma- thematical analysis of human-influenced relationships. The social environment can be expressed as patterns or regularities in relationships among interacting units [1]. Each social network can be represented as a graph made of nodes or ac- tors (e.g. individuals, organizations, information) that are tied by one or more spe- cific types of relations (e.g., financial exchange, trade, friends, and Web links).
    [Show full text]
  • Arxiv:2105.01931V2 [Physics.Soc-Ph] 24 May 2021 Barrat Et Al., 2008; Boccaletti Et Al., 2006; Albert and Barab´Asi, 2002)
    Centralities in complex networks Alexandre Bovet1, ∗ and Hern´anA. Makse2, y 1Mathematical Institute, University of Oxford, United Kingdom 2Levich Institute and Physics Department, City College of New York, New York, NY 10031, USA I. GLOSSARY NetworkA network is a collection of nodes (also called vertices) and edges (also called links) linking pair of nodes. Mathematically, it is represented by a graph G = (V; E) where V is the set of nodes and E ⊆ V × V is the set of edges. Additional information can be attached to each node or edge, for example edges can have different weights. Edges can be undirected or directed. Adjacency matrix The adjacency matrix, A, of a network is a N × N matrix (N = jV j) with element Aij = 1 if there is an edge from node i and to node j and Aij = 0 otherwise. If the network is weighted, Aij = wij where wij 2 R is the weight associated with the edge between nodes i and j if it exists and Aij = 0 otherwise. For undirected network, Aij = Aji, i.e. A is symmetric. Degree of a node The degree, ki, of node i in an undirected network is equal to its number of connections, i.e. P in P ki = j Aij. For directed network, we differentiate the in-degree, ki = j Aji and the out- out P degree, ki = j Aij, i.e. the number of edges in-coming to node i and out-coming from node i, respectively. In weighted undirected networks, the degree of a node is replaced by its strength, P si = j wij or in-strength and out-strength for weighted directed networks.
    [Show full text]