CS Department’s “5 Minutes with Kurt”

Posted by Kurt on March 8th, 2009

You knew you were headed for a career in Computer Science when…
I witnessed the thrill and the excitement of the dot com boom in the late 90’s.

What is your favorite class and why?
Theory of Computer Algorithms. This course is the first formal, in-depth course on algorithms, complexity, and data structures. These three components are the foundations of Computer Science and I highly recommend that everyone take this course (although it is a very difficult course).

One piece of advice I have for 1st year students is…
Establish a relationship with your professors by asking questions in class and utilizing office hours when you are confused.

If you could have dinner with a famous computer scientist, living or dead, who would you choose?
Luis von Ahn. His work on CAPTCHAs and human computation has inspired me to pursue it as my thesis topic.

What is the most interesting project you have worked on, either in a course or on the job?
The most interesting project I’ve worked on has been my thesis. Reading all of the existing research has helped me develop a brand new idea that nobody else in the world has worked on.

Where do you see yourself in ten years?
Hopefully back in school earning my PhD in Computer Science.

Original post: http://www.cs.rit.edu/about/profiles/Kurt_Kluever
PDF version: http://www.cs.rit.edu/five_minutes/pdf/Kurt_Kluever.pdf

Also check out 5 Minutes with Richard Zanibbi (my thesis advisor) and 5 Minutes with Brian Renzenbrink (a good friend).

Video CAPTCHAs at Center for Imaging Science

Posted by Kurt on January 30th, 2009

On January 28th, 2009, my thesis advisor (Richard Zanibbi) presented a talk on Video CAPTCHAs at the RIT Center for Imaging Science. An abstract of the talk can be download here. A video of his talk (with slides) can be watched here using Adobe Acrobat Connect.

Evaluating the Usability and Security of a Video CAPTCHA

Posted by Kurt on August 18th, 2008

I just scheduled the time and location for my thesis defense. Everyone is welcome to come, watch, and try to stump me with questions. Hope to see you there! -Kurt

Thesis Statement

One can increase usability while maintaining security in a video CAPTCHA by intelligently extending the set of user-supplied and ground truth tags.


A CAPTCHA is a variation of the Turing test, in which a challenge is used to distinguish humans from computers (”bots”) on the internet. They are commonly used to prevent the abuse of online services. CAPTCHAs discriminate using hard artificial intelligence problems: the most common type requires a user to transcribe distorted characters displayed within a noisy image. Unfortunately, many users find them frustrating and break rates as high as 60% have been reported (for Microsoft’s Hotmail).

We present a new CAPTCHA in which users provide three words (”tags”) that describe a video. A challenge is passed if a user’s tag belongs to a set of automatically generated ground-truth tags. In an experiment, we were able to increase human pass rates for our video CAPTCHAs from 69.7% to 90.2% (184 participants over 20 videos). Under the same conditions, the pass rate for an attack submitting the three most frequent tags (estimated over 86,368 videos) remained nearly constant (5% over the 20 videos, roughly 12.9% over a separate sample of 5146 videos). Challenge videos were taken from YouTube.com. For each video, 90 tags were added from related videos to the ground-truth set; security was maintained by pruning all tags with a frequency ≥ 0.6%. Tag stemming and approximate matching were also used to increase human pass rates. Only 20.1% of participants preferred text-based CAPTCHAs, while 58.2% preferred our video-based alternative.

Finally, we demonstrate how our technique for extending the ground truth tags allows for different usability/security trade-offs, and discuss how it can be applied to other types of CAPTCHAs.

Thesis Committee

Thesis Defense

Time: Thursday, August 28, 2008 at 10:00 a.m.
Location: Building 70, Room 3000


Live Demo


Bibtex Entry

	Title = {Evaluating the Usability and Security of a Video CAPTCHA},
	Author = {Kurt Alfred Kluever},
	School = {Rochester Institute of Technology},
	Address = {Rochester, NY, USA},
	Month = {August},
	Year = {2008}

Video CAPTCHA Experiment

Posted by Kurt on August 7th, 2008

You are invited to try a new video-based CAPTCHA developed within the Computer Science Department at RIT. A CAPTCHA is a challenge designed to distinguish humans from computer programs (’bots’) on the internet; they are typically implemented as a string of distorted characters which must be transcribed.

Many people find the text-based CAPTCHAs frustrating, so we have developed a video-based alternative. In our Video CAPTCHAs, a user must quickly label a video with three tags (words) describing its content.

We would appreciate it if you could help us evaluate the usability of this new approach by completing 20 Video CAPTCHAs. The experiment will only take about 15 minutes of your time. The task may be found at:


Thank you very much for your time.

Kurt Alfred Kluever (MS Student)
Richard Zanibbi (Supervisor)

Document and Pattern Recognition Lab
Department of Computer Science
Rochester Institute of Technology

GCCIS Welcomes 1st Graders from Canandaigua

Posted by Kurt on May 5th, 2008

RIT hosted the Golisano College Kids of 2023 for an activity inspired by CS Unplugged. We had a ton of fun with the 26 first graders from Canandaigua Primary School and even taught them how to convert to and from binary!  There’s a short blurb about it in the GCCIS Women in Computing 2007/2008 Year in Review.  The class was celebrating their internationally award-winning video that promotes women in technology.  You can watch the video below:

Possibilities In Computing Conference

Posted by Kurt on April 2nd, 2008

RIT hosted the second annual Possibilities In Computing conference in the Golisano College atrium. It was designed for guidance counselors, computing, math and technology teachers to learn about the latest job opportunities and degree programs. I volunteered to share my experiences and thoughts with the attendees and met some great people from the local highschools.

CS Community: Sample Technical Interview

Posted by Kurt on March 24th, 2008

I prepared a sample technical interview for the Speed Networking Spectacular event hosted by the CSC. It contains some general info about the technical interview process, some sample technical questions, and a mind puzzler. The questions are based on examples from Programming Interviews Exposed: Secrets to Landing Your Next Job. You can download the document here!

Joined the Document and Pattern Recognition Lab

Posted by Kurt on October 1st, 2007

For my Master’s thesis, I’ve decided to work in the Department of Computer Science’s new Document and Pattern Recognition Lab (DPRL) lab under the advisement of Dr. Richard Zanibbi. My area of research will be Human Interactive Proofs / CAPTCHAs.

Featured in Student Spotlight

Posted by Kurt on September 3rd, 2007

I was spotlighted by the Computer Science Department in the latest ‘Undergraduate Quarterly’ newsletter (Volume 2, Issue 1, Fall 20071) that was released on September 3rd, 2007. The newsletter contains important dates, announcements, a student spotlight and an alumni spotlight. The newsletter can be found scattered around the Golisano building and online here. Many thanks to Christina for putting the newsletter together.

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