Analyzing the Evolution of Scientific Citations & Collaborations: A Multiplex Network Approach

1. Analyzing the Evolution of Scientific Citations & Collaborations: A Multiplex Network Approach By SoumajitPramanik Guide : Dr. BivasMitra

2. Citation Network • Important Author-based Metrics: • In-Citation Count • H-Index etc.

3. Co-Authorship Network

4. Existing Works • Previous works on Citation Network mainly focused on: • Analyzing the evolution of citation and collaboration networks using “Preferential Attachment” [Barabasi et al. 2002] • Understanding the importance of community structure in citation networks [Chin et al. 2006] • Studying the evolution of research topics [He et al. 2009]

5. Continued… • Previous works on Collaboration Network mainly focused on: • Adopting social network measures of degree, closeness, betweenness and eigenvector centrality to explore individuals’ positions in a given co-authorship network [Liu et al. 2005]. • Analyzing the importance of the geographical proximity (same university/city/country etc.) of the collaborators [Divakarmurthy et al. 2011].

6. Motivation: 1. Existing studies focused on the dominant factors like preferential attachment 2. None of these factors can be self- regulated. 3. Does their exist any self-tunable factor (suppressed by dominant factors) for boosting own citations/collaboration?

7. Continued… Advantage of attending Conferences: Face-to-Face interactions with Fellow Scientists Studying the influence of such interactions on the evolution of Citation and Collaboration Networks

8. Assumptions: • The authors, whose talks are scheduled in the same technical session of a conference, have high chances of interaction. • In general, the first or the last author (or sometimes both) of a paper attends the conference.

9. Real Dataset: • Citations & Collaborations: • DBLPDataset for Computer Science domain (1960-2008) • Around 1 million papers along with information about author, year, venue and references • 501060 authors tagged with continents (using Microsoft Academic Search) • 6559415 author-wise citation links http://arnetminer.org/citation http://cse.iitkgp.ac.in/resgrp/cnerg/Files/resources.html

10. Continued… • Interactions: • Two domains: 1> Networking & Distributed Computing 2> Artificial Intelligence • Selected 3 leading conferences from each domain: 1> INFOCOM, ICDCS, IPDPS from the first domain (1982-2007) 2> AAAI, ICRA, ICDE from the second domain (1980-2008) • Collected session information from DBLP and program schedule of the conferences

11. Synthetic Dataset: • To regulate some important parameters and manifest their effects on the citation network • Followed statistics regarding articles per field per year, distribution of the number of authors in a paper and citation information from the real dataset • Only tunable parameter used: Successful interaction Rate p (p=0.1,0.2,…,1)

12. Methodology: • Multiplex Network Construction: For each year t: • Citation Layer: Directed author-wise citation links created at t, pointing to papers published before t (or sometimes, in t) • Interaction Layer: Undirected interaction links between authors presenting in same sessions in selected conferences in t • Co-authorship Layer: Undirected collaboration links between two authors if they co-author a paper published in those chosen conferences in t

13. Continued…

14. Evaluation Metrics: • 1. Conversion Rate (CR) for a conference C for a time-span T: No. of “Successful” interactions in C during T -------------------------------------- Total no. of interactions in C during T From this, the definition of the Overall Conversion rate can be simply extended.

15. Continued… • 2. Induced Citation Link Repetition (LR): LR measures the no. of times each “induced” citation link appears within the recorded time period. • 3. Lifespan of Induced citation (LS): The Lifespan of an “induced” citation is measured as the difference between the first and the last appearing year of the “induced” citation link.

16. Continued… • 4. Rate of appearance (RA): The rate of appearance of the of a induced citation link is denoted by the ratio of the repetition count and lifespan. Hence RA = LR / LS • 5. Influence of successful interaction (IG): The influence of a “successful” interaction is measured as the latency between the “successful” interaction and the formation of the first induced citation.

17. Interactions to Citations

18. Conversion Rates • Real Datasets: Networking Domain: 2.87% (381 out of 13240) for [0.9,0.1] interaction probabilities AI Domain: 2.1% (1291 out of 61896) for [0.9,0.1] interaction probabilities

19. Continued… • Synthetic Dataset: Downfall near end years due to “Boundary Effect”

20. Heat-Maps Networking Domain: 1. Overall Value increasing 2. Distributed Contribution AI Domain: 1. Overall Value slowly increasing 2. Dominated Contribution

21. Induced Citation Repetition (LR) & Lifespan (Ls) In both domains, Power-Law distribution A significant no. of “induced” citations repeat a high no. of times Networking Domain AI Domain Significant no. of “induced” citations have high RA values Reasons can be a) Low LS or/and b) High LR Networking Domain AI Domain AI Domain

22. Continued… Networking Domain AI Domain 1. High RA ratio results from mainly low LS 2. Ä large no. of induced" citations missing from the right side of the plot due to the boundary effect. Networking Domain 1. Aperiodicity of repetitions of “induced” citations increase almost linearly with their Lifespan 2. High LR not necessarily imply high standard deviation AI Domain

23. Networking Domain All the highly repeating “induced” citations have low “Influence” Gap • Influence Gap (IG) • Influence of Continents AI Domain Dominance of North America-North America pairs AI Domain Networking Domain

24. Correlation Values

25. Citations To Collaborations

26. Conversion Rates • 1. Considered only collaboration between established researchers (having at least 1 publication) • 2. In Networking domain out of 8920 co-author links, 2495 (28%) exhibits a past history of mutual citations! • 3. In AI domain 3211 out of 10192 (31.5%) are such “induced” co-author links. • Induced Collaboration Repetition Count and Influence Gap Networking Domain Here also, all highly repeating “induced” collaborations have small “influence” gap AI Domain

27. Component Evolution Networking Domain: 1. Giant component size 8152, Second Largest Component size 63 2. 28% (167) of induced collaboration links took part in the merging process AI Domain: 1. Giant component size 16203, Second Largest Component size 41 2. 36:6% (263) of induced collaboration links took part in the merging process

28. Conclusion & Future Plans • Interactions during conferences can be used as a tool to boost own citation-count. • This can indirectly help in creating effective future collaborations and this cycle goes on. • With time people are being more and more aware about the benefits of interacting with fellow researchers during conferences. • Need to check • 1. Influence of specific fields of interacting authors on creation of “induced” citations • 2. Effects of “induced” citations/collaborations on the citation/collaboration degree distribution • 3. Modeling the dynamics

29. References • 1. A. L. Barabasi, H. Jeong, Z. Neda, E. Ravasz, A. Schubert, and T. Vicsek: “Evolution of the social network of scientic collaborations”. Physica A: Statistical Mechanics and its Applications, 311(3-4):590 - 614, 2002. • 2. A. Chin and M. Chignell.: “A social hypertext model for finding community in blogs. In HYPERTEXT '06”. Proceedings of the seventeenth conference on Hypertext and hypermedia, pages 11-22, New York, NY, USA, 2006. ACM Press. • 3. Q. He, B. Chen, J. Pei, B. Qiu, P. Mitra, and C. L. Giles: “Detecting topic evolution in scientific literature: how can citations help?” In CIKM, pages 957-966, 2009. • 4. X. Liu, J. Bollen, M. L. Nelson, and H. Van de Sompel.: “Co-authorship networks in the digital library research community”. Information processing & management, 41(6):1462-1480, 2005. • 5. P. Divakarmurthy, P. Biswas, and R. Menezes.: “A temporal analysis of geographical distances in computer science collaborations”. In SocialCom/PASSAT, pages 657-660. IEEE, 2011.

30. Thank you…