ソーシャル・ネットワーキング・サービスにおける人的ネットワークの構造  [in Japanese] Structural Analysis of Human Network in Social Networking Services  [in Japanese]

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Abstract

ソーシャル・ネットワーキング・サービス(SNS: Social Networking Services)というWeb 上でのサービスが世界中で急激な拡大を続けている.SNS においては,先行研究では把握が困難な,相互認証された友人関係という人的ネットワークが大規模に顕在化している.本報告では,日本最大規模のSNS であるmixi(ミクシィ)の2005 年2 月15 日時点における36 万ノード・190 万リンクの人的ネットワークを分析した.基本的なネットワーク解析結果として,次数のゆるやかなスケールフリー性,高い凝集性が確認された.構造を視認するために粗視化を行った.近年開発された解析アルゴリズムを適用し部分的なつながり(link)が密になっている高密度集団(community)を抽出した.解析結果から独特な内部構造が視覚的に確認された.高密度集団は規模別に大中小の3 種類に大別された.詳細に高密度集団の人数のばらつきを調べると,集団の人数に全体のトレンドとしてZipf則が見いだされた.そして100 人から300 人ほどの高密度集団が分離されず,100 人以下から,300人以上の集団へとサイズがスキップするという現象を発見した.発見された内部構造は,既存のモデルでは説明できない独特のものであることを確認した.新しいコミュニケーション・インフラへの進化も期待できるSNS,その研究の端緒を報告する.Social Networking Services (SNS) have recently prevailed all over the World Wide Web. People grow up connections by making a tie to another who acknowledges as being a friend. Such a giant network of people, with each link being a mutually acknowledged friendship, has not ever been under previous investigation. This work analyzed the largest SNS in japan, called mixi, comprised of 360,000 nodes and 1.9million links as of February 15, 2005. Our analysis shows scale-free distribution of degree in its tail, and high cliquishness. To observe structure by coarse-graining, we employed a community (highly intra-connected group) extracting method developed by other researchers. As a result, we uncovered three classes of communities according to size. Overall rank-size plot shows Zipf's law for community-size distribution. Nevertheless, we found the existence of a skip in size, which implies absence of community between 100 and 300 in the number of people. This structure cannot be explained by models such as preferential attachment nor connecting nearest neighbor. We report some results of our analysis in anticipation to future advent and development of SNS as an innovative human communication infrastructure.

Social Networking Services (SNS) have recently prevailed all over the World Wide Web. People grow up connections by making a tie to another who acknowledges as being a friend. Such a giant network of people, with each link being a mutually acknowledged friendship, has not ever been under previous investigation. This work analyzed the largest SNS in japan, called mixi, comprised of 360,000 nodes and 1.9 million links as of February 15, 2005. Our analysis shows scale-free distribution of degree in its tail, and high cliquishness. To observe structure by coarse-graining, we employed a community (highly intra-connected group) extracting method developed by other researchers. As a result, we uncovered three classes of communities according to size. Overall rank-size plot shows Zipf's law for community-size distribution. Nevertheless, we found the existence of a skip in size, which implies absence of community between 100 and 300 in the number of people. This structure cannot be explained by models such as preferential attachment nor connecting nearest neighbor. We report some results of our analysis in anticipation to future advent and development of SNS as an innovative human communication infrastructure.

Journal

  • IPSJ journal

    IPSJ journal 47(3), 865-874, 2006-03-15

    Information Processing Society of Japan (IPSJ)

References:  13

Cited by:  31

Codes

  • NII Article ID (NAID)
    110004708844
  • NII NACSIS-CAT ID (NCID)
    AN00116647
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    1882-7764
  • NDL Article ID
    7875626
  • NDL Source Classification
    ZM13(科学技術--科学技術一般--データ処理・計算機)
  • NDL Call No.
    Z14-741
  • Data Source
    CJP  CJPref  NDL  NII-ELS  IPSJ 
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