Network community detection via iterative edge removal in a flocking-like system

We present a network community-detection technique based on properties that emerge from a nature-inspired system of aligning particles. Initially, each vertex is assigned a random-direction unit vector. A nonlinear dynamic law is established so that neighboring vertices try to become aligned with each other. After some time, the system stops and edges that connect the least-aligned pairs of vertices are removed. Then the evolution starts over without the removed edges, and after enough number of removal rounds, each community becomes a connected component. The proposed approach is evaluated using widely-accepted benchmarks and real-world networks. Experimental results reveal that the method is robust and excels on a wide variety of networks. Moreover, for large sparse networks, the edge-removal process runs in quasilinear time, which enables application in large-scale networks

Optimizing community detection in social networks using antlion and K-median

Antlion Optimization (ALO) is one of the latest population based optimization methods that proved its good performance in a variety of applications. The ALO algorithm copies the hunting mechanism of antlions to ants in nature. Community detection in social networks is conclusive to understanding the concepts of the networks. Identifying network communities can be viewed as a problem of clustering a set of nodes into communities. k-median clustering is one of the popular techniques that has been applied in clustering. The problem of clustering network can be formalized as an optimization problem where a qualitatively objective function that captures the intuition of a cluster as a set of nodes with better in ternal connectivity than external connectivity is selected to be optimized. In this paper, a mixture antlion optimization and k-median for solving the community detection problem is proposed and named as K-median Modularity ALO. Experimental results which are applied on real life networks show the ability of the mixture antlion optimization and k-median to detect successfully an optimized community structure based on putting the modularity as an objective function

STUDI AWAL PENGELOMPOKAN DATA TWITTER TOKOH POLITIK INDONESIA MENGGUNAKAN GRAPH CLUSTERING

Twitter sebagai sosial media yang populer, memiliki jumlah pengguna yang sangat besar. Pengelompokan pengguna Twitter menjadi penting untuk dilakukan. Salah satunya dapat menjadi strategi marketing suatu perusahaan dalam memasarkan produk yang digunakan. Pengelompokan dapat dilakukan dengan memanfaatkan fitur-fitur Twitter yang kemudian dimodelkan dalam bentuk  graph sehingga dapat dilakukan graph clustering. Penelitian ini membandingkan tiga metode graph clustering yaitu  fastgreedy,  walktrap  dan  leading eigenvector  dengan menggunakan 23000  tweet  dari 96 akun politisi Indonesia. Dari hasil penelitian, nilai purity yang diperoleh adalah antara 0.7-0.8. Dengan nilai purity  tertinggi diperoleh saat menggunakan algoritma  walktrap  dan  leading eigenvector  yaitu 0.833 dimana fitur Twitter yang digunakan adalah fitur mentions.  Kata kunci:  Twitter, graph clustering, fastgreedy, walktrap, leading eigenvector, deteksi komunita

Modelling human network behaviour using simulation and optimization tools: the need for hybridization

The inclusion of stakeholder behaviour in Operations Research / Industrial Engineering (OR/IE) models has gained much attention in recent years. Behavioural and cognitive traits of people and groups have been integrated in simulation models (mainly through agent-based approaches) as well as in optimization algorithms. However, especially the influence of relations between different actors in human networks is a broad and interdisciplinary topic that has not yet been fully investigated. This paper analyses, from an OR/IE point of view, the existing literature on behaviour-related factors in human networks. This review covers different application fields, including: supply chain management, public policies in emergency situations, and Internet-based human networks. The review reveals that the methodological approach of choice (either simulation or optimization) is highly dependent on the application area. However, an integrated approach combining simulation and optimization is rarely used. Thus, the paper proposes the hybridization of simulation with optimization as one of the best strategies to incorporate human behaviour in human networks and the resulting uncertainty, randomness, and dynamism in related OR/IE models.Peer Reviewe

Community Detection In Social Networks Using Parallel Clique-finding Ants

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Bilişim Enstitüsü, 2010Thesis (M.Sc.) -- İstanbul Technical University, Institute of Informatics, 2010İnternet ağının sürekli artan popülaritesiyle birlikte, insanlar daha çok bilgiyi ağ üzerinden dünyanın geri kalanıyla paylaşmaya ve geliştirmeye başladılar; buna bağlı olarak farklı disiplinlerde sosyal ağların analizi konusu da popüler hale geldi. Günümüzde sosyal ağlar üzerinde bulunan topluluk yapılarının tespiti, bilgisayar bilimleri açısından da önem kazandı. Bu amaçla kullanılan topluluk bulma algoritmaları iyi sonuçlar üretse de, büyük ölçekli sosyal ağlarda işlem karmaşıklığı ve buna bağlı ölçeklendirme konusunda yetersiz kalmaktadır. Bu tezin ana amacı, elde bulunan sosyal ağ çizgesini, çizgenin ana özelliklerini koruyarak daha küçük bir hale indirgemek, dolayısıyla topluluk bulma algoritmalarının verimini çözüm kalitesinden kayıp olmadan arttırmaktır. Bu çalışmada Karınca Kolonisi İyileştirme yöntemi sayesinde yarı bağlı alt çizgeler bulunmakta ve bu alt çizgeler ile ana çizge daha küçük bir hale indirgenmekte, son olarak indirgenmiş çizge üzerinde topluluk bulma algoritmaları koşturulmaktadır. Çeşitli sosyal ağ çizgeleri üzerinde koşulan testlerin sonuçları, uygulanan indirgeme yöntemi sonrasında topluluk bulma algoritmalarının çalışma sürelerinde iyileşme gözlenmiş, buna bağlı olarak indirgenme sonrasında çözüm kalitesinin de korunduğu tespit edilmiştir.Attractiveness of social network analysis as a research topic in many different disciplines is growing in parallel to the continuous growth of the Internet, which allows people to share and collaborate more. Nowadays, detection of community structures, which may be established on social networks, is a popular topic in Computer Science. High computational costs and non-scalability on large-scale social networks are the biggest drawbacks of popular community detection methods. The main aim of this thesis is to reduce the original network graph to a maintainable size so that computational costs decrease without loss of solution quality, thus increasing scalability on such networks. In this study, we focus on Ant Colony Optimization techniques to find quasi-cliques in the network and assign these quasi-cliques as nodes in a reduced graph to use with community detection algorithms. Experiments are performed on commonly used social networks with the addition of several large-scale networks. Based on the experimental results on various sized social networks, we may say that the execution times of the community detection methods are decreased while the overall quality of the solution is preserved.Yüksek LisansM.Sc

A self-organizing algorithm for community structure analysis in complex networks

Community structure analysis is a critical task for complex network analysis. It helps us to understand the properties of the system that a complex network represents, and has significance to a wide range of real applications. The Label Propagation Algorithm (LPA) is currently the most popular community structure analysis algorithm due to its near linear time complexity. However, the performance of the LPA has proven to be unstable and the correctness of community assignment of nodes is unsatisfactory. In this paper a Self-Organizing Community Detection and Analytic Algorithm (SOCDA2) based on swarm intelligence is proposed. In the algorithm, a network is modeled as a swarm intelligence system, while each node within the network acts iteratively to join or leave communities based on a set of pre-defined node action rules, in order to improve the quality of the communities. When there is not a node changing its belonging community anymore, an optimal community structure will emerge as a result. A variety of experiments conducted on both synthesized and real-world networks have shown results which indicate that the proposed algorithm can effectively detect community structures and the performance is better than that of the LPA. In addition, the algorithm can be extended for overlapping community detection and be parallelized for largescale network analysis