在线社会系统的若干问题研究 刘建国 上海理工大学复杂系统科学研究中心

Presentation on theme: "在线社会系统的若干问题研究 刘建国 上海理工大学复杂系统科学研究中心"— Presentation transcript:

1 在线社会系统的若干问题研究 刘建国 上海理工大学复杂系统科学研究中心 E-mail:liujg004@ustc.edu.cn

2 Team member and collaborators
Complexity research center of USST 博士：傅家旗，刘晓露，杨凯 研三：任卓明，胡兆龙，杨光勇 研二：侯磊，宋文君，张一璐 研一：林坚洪，计磊，王江盼，唐丽英 University of Fribourg Prof. Yi-Cheng Zhang Said Business School, University of Oxford Prof. Felix Reed-Tsochas Prof. Robin Dunbar Dr. Mason Porter

3

4 Facebook 2010年数据 Facebook 2013年数据

5 2013年全球B2C电子商务销售额达1.2万亿美元

6 The possible science questions
How to measure the impact of the modern communication tools on human collective behaviors? Whether the modern communication tools have change our behavior pattern? And how? What is the relationship between the online and offline behaviors? How to rank the node importance of the large-scale social networks? How to identify the evolution pattern of the online user reputation and project quality? What is the social influence? How to measure the online user interests? ……?

7 Statistical properties of Facebook user interaction behaviors
Collective behavior analysis of online users User interest measurement Identifying the node importance

8 Facebook user interaction behaviors
Dunbar’s Number is an estimate of the sizes of human and primate social networks. Dunbar discovered that the size of the neocortex is strongly correleated to group sizes.

9 Related works Y. Ahn, S. Han, H. Kwak, S. Moon and H. Jeong, Analysis of topological characteristics of huge online social networking services. in: Proceedings of the 16th international conference on World Wide Web, New York, 2007, p Mean number of friends 46 S.A. Golder, D. Wilkinson and B.A. Huberman, Rhythms of social interaction: messaging within a massive online network. in: Proceedings of the 3rd International Conference on Communities and Technologies Conference, Michigan State, 2007, p Mean number of friends Goncalves, N. Perra and A. Vespignani, Modeling users’ activity on Twitter networks: validation of Dunbar’ number. PLoS One 6(8) (2011) e Mean number of friends C. Mccarty, P.D. Killworth, H.R. Bernard, E.C. Johnsen and G.A. Shelley, Comparing two methods for estimating network size. Human Organization 60(1) (2001) Mean number of friends 291.

10 The data of Facebook are collected from New Orleans.
From Sep. 14th, 2004 to Jan. 22nd, EPL 104 （2013） 28004

11 We find that, for the growth rate of the number of users’ posts, there is a transformation point at kout = 65. The average link weight reaches a maximum when kout ranges from 28 to 65, and after that it drops down quickly while before that it rises sharply, which suggests that the stable and meaningful social circle is roughly 65 There are still some restrictions on our social capabilities in spite of the modern technology and communication tools.

12 Online user collective behaviors
measured the number of users with degree k who gives ratings to objects with degree

13 Recommendations

14

15 Ceiling effect of online user interests for the movies

16 Evolution Pattern of the Network Nucleus in Facebook

17 Nat Phys 6:

18 Statistical properties of the network nucleus of Facebook
(a) The Facebook-link plot of all nodes are ordered by Ks; (b) The Facebook-wall plot of all nodes.

19 User interests and recommendations

20 Object degree distributions of the recommendation lists

21 Property of the directed user similarity

22 The average neighbor degree and its variance

23

24 GRM is a global ranking method;
CF is the collaborative filtering algorithm based on random walks; Heter-CF is a modified CF algorithm, in which the user similarity is defined based on the mass diffusion process. CB-CF refers to the CF algorithm on weighted bipartite network; Hybrid is an abbreviation for the hybrid algorithm.

25 Node importance ranking based on the k-shell decomposition method

26 Zhuoming Ren, Jianguo Liu, 392, 4154-4159 (2013)
网络中的节点重要性评价-1 Zhuoming Ren, Jianguo Liu, 392,  (2013)

27 network. the network of University Rovirai Virgili (URV) of Spain contains faculty, researchers, technicians, managers, administrators, and graduate students Peer-To-Peer (P2P). A sequence of snapshots of the Gnutella peer-to-peer file sharing network from August Each node represents a host in the Gnutella network and each link represents the connection between each pair of Gnutella hosts. Pretty-Good-Privacy (PGP). Pretty-Good-Privacy algorithm have been developed in order to maintain privacy between peers, wherefore, it is also called web of trust of PGP. Autonomous Systems (AS). The data was collected from University of Oregon Route Views Project

28 Kendall's tau is a measure of rank correlation, i. e
Kendall's tau is a measure of rank correlation, i.e., the similarity of the orderings of the data. Tau equals to 1 if two vectors are exactly same, equals to 0 if two vectors are uncorrelated. Closeness Centrality(CC)

29 The results on the BA network

30 国家自然科学基金(61374177): 在线社会网络的时序分析理论及其应用研究.
国家自然科学基金( ): 基于通讯和移动模式分析的社会网络演化机制与动力学研究. 国家自然科学基金( ): 基于兴趣图谱的社会网络演化机制研究. 国家自然科学基金( ): 非常规突发事件恐慌群体行为分析与疏导机制研究. [已结题] 国家自然科学基金( ) : 复杂动态网络的信息自动过滤问题研究.[已结题] 国家自然科学基金( ) : 基于超网络模型的科学知识图谱分析研究.[已结题]

31 PloS ONE 9(3) e89746  (2014) ; EPL 106, (2014); EPL  (2013) ； Physica A 402, (2014); Physica A 401, (2014); Physica A 400, (2014); Euro. Phys. J B, (2013) ； Chin. Phys. B, 23(1) (2013)； 物理学报, 62(21) (2013).； Physica A 392(18),  (2013). 

32 Thank you！！

33