1 / 13

Today’s topics

Today’s topics. Strength of Weak Ties Next Topic How does Google rank webpages in search? Acknowledgements James Moody, Alan Kirman , Dejan Vinkovic. F actors influencing diffusion. Network structure ( unweighted ) density degree distribution clustering connected components

zeroun
Download Presentation

Today’s topics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Today’s topics Strength of Weak Ties Next Topic How does Google rank webpages in search? Acknowledgements James Moody, Alan Kirman, DejanVinkovic

  2. Factors influencing diffusion • Network structure (unweighted) • density • degree distribution • clustering • connected components • community structure • Strength of ties (weighted) • frequency of communication • strength of influence • Spreading agent • attractiveness and specificity of information

  3. How does strength of a tie influence diffusion? • M. S. Granovetter: The Strength of Weak Ties, AJS, 1973: • Finding a job through a contact that one saw • frequently (2+ times/week) 16.7% • occasionally (more than once a year but < 2x week) 55.6% • rarely 27.8% • But… length of path is short • contact directly works for/is the employer • or is connected directly to employer

  4. Strength of Weak Ties • Why do leads for new jobs come from weak contacts? • What binds communities together? • How do ties afffect access to resources? • What are the social implications?

  5. Strong ties • A strong tie • frequent contact • affinity • many mutual contacts • Less likely to be a bridge (or a local bridge) “forbidden triad”: strong ties are likely to “close” Source: Granovetter, M. (1973). "The Strength of Weak Ties", American Journal of Sociology, Vol. 78, Issue 6, May 1973, pp. 1360-1380.

  6. Triadic Closure

  7. Triadic Closure

  8. Triadic Closure

  9. Strength of ties on facebook

  10. Strength of ties on Facebook • Why are some ties more common than others?

  11. Strength of ties on twitter Study by Wu, Golder & Huberman

  12. Whatindicates cohesion? • Mutuality of ties • everybody in the group knows everybody else • Closeness or reachability of subgroup members • individuals are separated by at most n hops • Frequency of ties • Among members • everybody in the group has links to at least k others • Among subgroup members compared to nonmembers • Why? • Discover communities of practice • Measure isolation of groups • Threshold processes: • I will adopt an innovation if some number of my contacts do • I will vote for a measure if a fraction of my contacts do

  13. Columbia Small World Experiment • Identical protocol to Travers and Milgram, but conducted via the Internet • 60,000 participants from 170 countries attempting to reach 18 different targets • Results • Median “true” chain length 5 < L < 7 • Successful chains disproportionately used • professional ties (34% vs. 13%) • ties originating at work/college • target's work (65% vs. 40%) • weak ties (Granovetter) • . . . and disproportionately avoided • hubs (8% vs. 1%) (+ no evidence of funnels) • family/friendship ties (60% vs. 83%)

More Related