—Captchas are designed to be easy for humans but hard for machines. However, most recent research has focused only on making them hard for machines. In this paper, we present wha...
Elie Bursztein, Steven Bethard, Celine Fabry, John...
A CAPTCHA is a program that generates challenges that are easy to solve for humans but difficult to solve for computers. The most common CAPTCHAs today are text-based ones where a ...
Paul Baecher, Marc Fischlin, Lior Gordon, Robert L...
The ASIRRA CAPTCHA [6], recently proposed at ACM CCS 2007, relies on the problem of distinguishing images of cats and dogs (a task that humans are very good at). The security of AS...
"Human computation" is a recent approach that extracts information from large numbers of Web users. reCAPTCHA is a human computation project that improves the process of...
In examine the tutoring protocols of one expert human tutor tutoring 10 students in solving physics problems, four analyses reveal that he tutored the five good learners in differe...