Maximizing the Spread of Influence through a

Social Network

Kempe, Kleinberg, Tardos 2003

Ellie Clougherty

Goal: Which subset of individuals are the most

influential?

How can we select a subset of nodes that will have the

greatest impact?

Name: Ellie Clougherty

Can you find degree

centrality?

Can you find

distance centrality?

Network Data

Co-authorships of high-energy physics papers

Node: Author

Edges: Degree of co-authorship

Goal: Select the most influential nodes

An NP-Hard optimization problem!

Solution:

Naturally-greedy, hill-climbing, submodular algorithm obtains 63% of the optimal

solution

Two Models

Linear Threshold Model

A node becomes active when the total weight of it’s active neighbors exceeds a random threshold

Independent Cascade Model

An activated node has one chance to activate an inactive neighbor with a weighted probability

Weight: Number of Edges / Co-Authorships

Context Matters

Consider the dynamics of information in a network, not just the structure

Weighting the influence of one node to another depends on the context and nature of the data

Future Steps:

Generalized Framework: combine both models

Non-progressive models: activation is bi-directional

Additional Sources

Node Grid:http://en.wikipedia.org/wiki/Centrality#mediaviewer/File:Centrality.svg

Indian Grid:http://www.mnn.com/earth-matters/energy/stories/whats-wrong-with-indias-electric-grid

John Kelly Protesting: http://www.npr.org/2014/10/01/352757107/campus-sexual-assault-law-now-includes-language-on-same-sex-violence

UVA Protestors: http://www.nytimes.com/2014/11/25/us/rocked-by-rape-report-university-of-virginia-to-hold-special-meeting.html?smid=fb-nytimes&smtyp=cur&bicmp=AD&bicmlukp=WT.mc_id&bicmst=1409232722000&bicmet=1419773522000

EM Slide: http://sifaka.cs.uiuc.edu/~wang296/Course/IR_Fall/docs/PDFs/Language%20Models%20II.pdf

Truthy: http://truthy.indiana.edu/

Business Insider: http://www.businessinsider.com/what-makes-an-article-go-viral-2012-5