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Jure Leskovec Machine Learning Department Carnegie Mellon University. Who are the most influential bloggers?. Question…. I have 10 minutes. Which blogs should one read to be most up to date? Who are the most influential bloggers?. ?. News spreads….
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Jure Leskovec Machine Learning Department Carnegie Mellon University Who are the most influential bloggers?
Question… • I have 10 minutes. Which blogs should one read to be most up to date? • Who are the most influential bloggers? ?
News spreads… So, who is really the influential here? Obscure technology story Small tech blog Small tech blog Slashdot Wired New Scientist New York Times CNN BBC
Blogs: Information propagation We want to know about things before everyone else does. Detect blue & green soon but miss red. • Data: All posts from top 50,000 blogs for 1 year • 60 million posts, 120 million links Detect all stories but late.
Problem: Covering blogosphere • Given a budget (of blogs 3) • Which blogs to read to cover the blogosphere? • Bad news: Solving this exactly is NP-hard • Good news: Theorem: Our algorithm can do it in linear timeand with factor 3 approximation Blogosphere
Reading blogs • Which blogs to read to be most up to date? More info: www.blogcascades.org Our solution % of stories detected(higher is better) In-links (used by Technorati) Out-links # posts Random Number of selected blogs
[w/ Krause et al., J. of Water Resource Planning] Same problem: Water Network • Given: • a real city water distribution network • data on how contaminants spread over time • Place sensors (to save lives) • Problem posed by the US Environmental Protection Agency c1 S S c2
[w/ Ostfeld et al., J. of Water Resource Planning] Water network: Results CELF • Our approach performed best at the Battle of Water Sensor Networks competition Degree Random Population saved (higher is better) Population Flow Number of placed sensors