A new job, a new apartment, a new life?

Posted by Kurt on September 22nd, 2008

Since beginning my new job as a Software Engineer in Test for Google at their Manhattan office, a lot has changed in my life. Here’s a quick rundown:

My Job (Google)

My job is going great. I really love the work environment and people at Google. Everyone is willing to take time out of their day to help you with whatever you need…which is good because the project I’m working on has a very high learning curve. It uses a ton of Google-centric infastructure pieces that all work together in a very specific way. Since I’ve had no exposure to these technologies before, work has been going a little slow (lots of reading of other’s code and documentation, not a lot of coding). It’s a bit frustrating because it’s hard to measure productivity when most of your time is spent inputting knowledge (into your own brain), not outputting knowledge (to others). However, this means I’m learning something new every day (which is exciting). I’ll also excited to report that I’ll be continuing my work on Video CAPTCHAs at Google :)

My City (Hoboken)

There are tons and tons of young professionals everywhere. According to Wikipedia, the median age here is only 30 (as a comparison, the median age in the US is 35.3). While that doesn’t seem like a big difference, you’ll quickly notice it walking around the streets. The city of Hoboken itself is actually a lot of fun. Since the young population drives the local businesses, there are tons of bars, restaurants, and coffee shops in downtown Hoboken. In fact, no matter what day it is, the streets and bars are always full of people.

My Commute (Walk, PATH Train, Walk)

Nearly everyone here takes the PATH train into NYC for work. The PATH train is a bargain: for $1.30 (if you buy in bulk), you can get to midtown Manhattan in under 15 minutes. My train (from Hoboken to 14th Street) makes 2 stops along the way (at Christopher St and 9th St) and still only takes 11 minutes. That’s a faster commute than it would be even if I lived in most places in Manhattan. The only bad part of my commute is getting to the PATH station in Hoboken. It’s a mile walk from my apartment which isn’t bad now, but once the bad weather hits it’s going to be brutal. I’m going to try to get my bike down here to speed up the commute though. Once I get to 14th St, I have another half a mile or so walk to Google. Others have recommended that I take the L subway, but I’d rather save the $2 each way and walk the two blocks. Overall, my commute into the city costs me $1.30, a few hundred calories, and about 40 minutes of my time.

My Car (A Sad S4)

One of the main reasons that I decided on the apartment that I’m in is that it came with a free garaged parking spot my for S4. However, I’ve quickly realized that having a car down here is rather pointless. I’ve only used it two times since moving down here: 1) buying furniture on move in day 2) returning an air mattress to BJs. Other than that, it sits in the garage and looks at me in anger: it wants to be driven. Next weekend I’ll be driving up to Rochester to present at the IEEE WNYIP 2008 workshop…that’ll cheer my car up :) Also, gas is really cheap (comparatively) down here: $3.30/gallon for regular.

My Eating (An Empty Fridge)

I do all my weekday eating at Google: breakfast (sometimes), lunch (always), and dinner (except on Fridays). Because of this, I have very little (read: no) food in my fridge. In fact, all I have at my apartment is 3 mini-bags of popcorn and some soda. On the weekends, I go out to eat. There’s no sense in going grocery shopping for the weekend only. I’m sure at some point I’ll stock my cabinets with non-perishables like soup, etc. Also I should note that I may end up dying of mercury poisoning due to the amount of fish I’m eating at Google every day.

Video CAPTCHAs: Usability vs. Security

Posted by Kurt on September 13th, 2008

On September 26th, 2008 I will be presenting some of my work on Video CAPTCHAs at the IEEE Western New York Image Processing Workshop 2008 in Rochester, NY. The workshop will be held in the Imaging Science building at RIT (registration details can be found at the above link). The paper is in the form of a 4 page “extended abstract” and can be downloaded below.


The paper can be downloaded here or from the RIT Digital Media Library.

Bibtex Entry

	Title = {Video CAPTCHAs: Usability vs. Security},
	Author = {Kurt Alfred Kluever and Richard Zanibbi},
	Booktitle = {Proceedings of the IEEE Western New York Image Processing Workshop 2008},
	Address = {Rochester, NY, USA},
	Month = {September},
	Year = {2008}

Google Translate in Beta (for a reason)

Posted by Kurt on August 24th, 2008

The Google Translate service is quiet useful. However, I just ran into this little bug when playing around with it. If you submit a chunk of English text and ask it to detect the language and then translate it to English, it brings up an warning saying that they are “not yet able to translate from English to English”. Whoops :) I guess it’s in Beta for a reason.

Click the thumbnail for a full-sized image.

Video CAPTCHA Demo

Posted by Kurt on August 22nd, 2008

If you haven’t already, check out the Video CAPTCHA demo at:


There’s no entrance survey, exit survey and you can quit at any time (don’t feel obligated to finish all 22 videos).  Enjoy!

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}

My Hobby: Tossing whiteboard markers

Posted by Kurt on August 10th, 2008

In the spirit of the many xkcd comics, here is one of my (new) hobbies: tossing whiteboard markers. In the massive amounts of time I spend alone in my lab, I’ve developed a new game similar to an egg toss to entertain me while my code is executing. I’ll caution you in advance that it’s both extremely addicting and surprisingly loud. Oh yea, you will get some funny looks from anyone who witnesses the game.

The Game: Toss white board markers at the whiteboard and try to get them to land in the ledge/trough.

My current distance record is 18 feet, mostly because that’s the width of the lab.  I might have to open my door and start tossing them from the hallway…

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

Top Ten Most Frequent YouTube Tags

Posted by Kurt on August 5th, 2008

Over the past few months, I’ve been writing tons of code to perform analysis on YouTube tags. Luckily, they have a great API available in Java, .NET, Python, and PHP. I needed to obtain estimated tag frequencies on videos, but I couldn’t find this data available anywhere else online.  I ended up having to calculate them myself, so I thought I’d share the results:

  1. music, 1.78%
  2. video, 1.75%
  3. funny, 1.63%
  4. rock, 1.28%
  5. de, 1.11%
  6. dance, 0.95%
  7. film,0.88%
  8. 2008,0.82%
  9. live, 0.78%
  10. 2007, 0.77%

The list of tags to query was obtained by merging a standard Linux dictionary and the set of tags discovered during a random walk of the YouTube graph. The API was then queried to determine the estimated number of videos which contain the given tag. The above list is only a partial list, but the full list is available upon request.

Switched to WordPress Platform

Posted by Kurt on July 15th, 2008

Well I finally switched to a real blogging platform, namely WordPress. Since it will be a lot easier to post content, that means I should be posting more often (in theory at least). Also, I stole my theme choice from my friend’s blog @ RespectCapitalism.com. There are very few good looking WP themes in my opinion…sorry Ben :)

Video Tagging Experiment

Posted by Kurt on July 1st, 2008


As many of you know, I am in the process of completing my MS thesis in Computer Science at RIT. My area of research is online human verification (i.e., proving that a human is behind an online request, and not an automated computer program). When completing an online form, users are often presented with a distorted string of text which they are forced to transcribe. These are known as CAPTCHAs, and exist to prevent automated programs from abusing online services (humans can read the distorted text but most computer programs cannot). My thesis idea is to create a Video CAPTCHA, where instead of transcribing a string of distorted text, users must supply an appropriate label for a short video (a challenge which computers cannot complete but humans should be able to).

What you can do for me:

I have setup an online data collection website, which will allow me analyze how people label (tag) online videos. You will be asked to quickly tag 20 short online videos. I would greatly appreciate your help in completing the short (10-15 minutes) experiment at the following link:


Feel free to forward this request to anyone else you know who may be interested in participating. If you have any questions, please let me know. The experiment will remain open until July 14th, 2008.

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