PLEASE NOTE UNUSUAL LOCATION!

Speaker: Luis von Ahn

Time: Wednesday 12pm 

Place: NSH 3305

Thesis Oral

Title: Human Computation

Abstract:

Tasks like image recognition are trivial for humans, but continue to 
challenge even the most sophisticated computer programs. This thesis 
introduces a paradigm for utilizing human processing power to solve 
problems that computers cannot yet solve. Traditional approaches to 
solving such problems focus on improving software. I advocate a novel 
approach: constructively channel human brainpower using computer games. 
For example, the ESP Game, introduced in this thesis, is an enjoyable 
online game -- many people play over 40 hours a week -- and when people 
play, they help label images on the Web with descriptive keywords. These 
keywords can be used to significantly improve the accuracy of image 
search. People play the game not because they want to help, but because 
they enjoy it.

I introduce three other examples of games with a purpose: Peekaboom, 
which helps determine the location of objects in images, Phetch, which 
collects paragraph descriptions of arbitrary images to help 
accessibility of the Web, and Verbosity, which collects common-sense 
knowledge. I also show that, in principle, every problem that could be 
solved by a computer, today or in the future, could be solved using 
enjoyable computer games.

In addition, I introduce CAPTCHAs, automated tests that humans can pass 
but computer programs cannot. CAPTCHAs take advantage of human 
processing power in order to differentiate humans from computers, an 
ability that has important applications in practice.

The results of this thesis are currently in use by hundreds of Web sites 
and companies around the world, and some of the games presented here 
have been played by over 100,000 people. Practical applications of this 
work include improvements in problems such as: image search, 
adult-content filtering, spam, common-sense reasoning, computer vision, 
accessibility, and security in general.

Thesis Committee:
Manuel Blum, Chair
Takeo Kanade
Michael Reiter
Josh Benaloh, Microsoft Research
Jitendra Malik, University of California, Berkeley