Measurement and Analysis of Online Social Networks

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Measurement and Analysis of Online Social Networks. A. Mislove, M. Marcon, K Gummadi, P. Druschel, B. Bhattacharjee. Presentation by Shahan Khatchadourian Supervisor: Prof. Mariano P. Consens. Focus. graphs of online social networks how they were obtained how they were verified - PowerPoint PPT Presentation

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  • Measurement and Analysis of Online Social NetworksA. Mislove, M. Marcon, K Gummadi, P. Druschel, B. BhattacharjeePresentation byShahan KhatchadourianSupervisor: Prof. Mariano P. Consens

    Measurement and Analysis of Online Social Networks

  • Focusgraphs of online social networkshow they were obtainedhow they were verifiedhow measurement and analysis was performedproperties of obtained graphswhy these properties are relevant

    Measurement and Analysis of Online Social Networks

  • Why study the graphs?important to improve existing system and develop new applicationsinformation searchtrusted userswhat is the structure of online social networkswhat are different ways to examine a social network when complete data is not available?how do they compare with each other and to the Web?

    Measurement and Analysis of Online Social Networks

  • Which graphs?Flickr, YouTube, LiveJournal, and OrkutAll are directed except for OrkutWeakly Connected Component (WCC)Strongly Connected Component (SCC)

    Measurement and Analysis of Online Social Networks

  • How are the graphs obtained?APIusersgroupsforward/backward linksHTML Screen Scraping

    Measurement and Analysis of Online Social Networks

  • Summary of graph propertiessmall-worldscale-freecorrelation between indegree and outdegreelarge strongly connected core of high-degree nodes surrounded by small clusters of low-degree nodes

    Measurement and Analysis of Online Social Networks

  • Crawling Concerns - AlgorithmsBFS and DFSSnowball method: underestimates number of low-degree nodes. In social networks, they underestimate the power-law coefficient, but closely match other metrics such as overall clustering coefficient.

    Measurement and Analysis of Online Social Networks

  • Crawling Concerns FW linkscannot reach entire WCC

    Measurement and Analysis of Online Social Networks

  • How to Verify SamplesObtain a random user sampleLJ: feature which returns 5,000 random usersFlickr: random 8-digit user id generationConduct a crawl using these random users as seedsSee if these random nodes connect to the original WCCSee what the graph structure of the newly crawled graph compares to original

    Measurement and Analysis of Online Social Networks

  • Crawling Concerns FW linksno effect on largest WCC

    Measurement and Analysis of Online Social Networks

  • Crawling Concerns FW linksincreasing the size of the WCC by starting at a different seed

    Measurement and Analysis of Online Social Networks

  • Measurement and Analysis of Online Social Networks

  • Link Symmetryeven with directed links, there is a high level of symmetrypossibly contributed to by informing users of new incoming linksmakes it harder to identify reputable sources due to dilutionpossible sol: who initiated the link?

    Measurement and Analysis of Online Social Networks

  • Power-law node degreesOrkut deviates:only 11.3% of network reached (effect of partial BFS crawl Snowball method)artificial cap of users number of outgoing links, leads to a distortion in distribution of high degreesdiffers from Web

    Measurement and Analysis of Online Social Networks

  • Power-law node degrees

    Measurement and Analysis of Online Social Networks

  • Power-law node degreese.g. analysis of top keywords

    Measurement and Analysis of Online Social Networks

  • Spread of Information

    Measurement and Analysis of Online Social Networks

  • Power Law affectorsservices, accessibility, featuresmobile users10010010-810-8111000010000

    Measurement and Analysis of Online Social Networks

  • Correlation of indegree and outdegreeover 50% of nodes have indegree within 20% of their outdegree

    Measurement and Analysis of Online Social Networks

  • Path lengths and diameterall four networks have short path lengthBroder et al noted if Web were treated as undirected graph, path length would drop from 16 to 7, so what?

    Measurement and Analysis of Online Social Networks

  • Link degree correlationsJDD: joint degree distributionmapping between outdegree and average indegree of all nodes connected to nodes of that outdegreeYouTube different due to extremely popular users being connected to by many unpopular usersOrkut shows bump due to undersampling

    Measurement and Analysis of Online Social Networks

  • Joint degree distribution and Scale-free behaviourundersamplingof low-degreenodescelebrity-drivennaturecap on links

    Measurement and Analysis of Online Social Networks

  • Densely connected coreremoving 10% of core nodes results in breaking up graph into millions of very small SCCswhy an SCC? directed links matter for actual communicationgraphs below show results as nodes are removed starting with highest-degree nodes (left) and path length as graph is constructed beginning with highest-degree nodes(right)Sub logarithmic growth

    Measurement and Analysis of Online Social Networks

  • Tightly clustered fringebased on clustering coefficientsocial network graphs show stronger clustering, most likely due to mutual friendsPossibly because personal content is not shared

    Measurement and Analysis of Online Social Networks

  • Groupsgroup sizes follow power-law distributionrepresent tightly clustered communities

    Measurement and Analysis of Online Social Networks

  • GroupsOrkut special case maybe because of partial crawl

    Measurement and Analysis of Online Social Networks

  • Node Value DeterminationDirected Graph, current modelnodes with many incoming links (hubs) have value due to their connection to many usersit becomes easy to spread important information to the other nodes, e.g. DNSunhealthy in case of spam or virusesin order for a user to send spam, they have become a more important node, amass friends

    Measurement and Analysis of Online Social Networks

  • Node Value DeterminationLink Initiator, requires temporal informationif user A requests a link with user B, does that mean that user B is more important?even though graphs have a high level of link symmetry, this additional information can offset this symmetryunfortunately, examined graphs do not have temporal information

    Measurement and Analysis of Online Social Networks

  • Trustlendingclub.com, Facebook applicationpeople are more willing to lend money to friends who are linked through a short pathpeople are more willing to pay back those who are linked through a short pathno indication of whether this actually worksdoes trust increase as degree increases?what credit rating and JDD does a person have to get a good interest rate?

    Measurement and Analysis of Online Social Networks

  • Thank youshahan@cs

    Measurement and Analysis of Online Social Networks

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