Machine Learning Contests

I just found another machine learning contest site called TunedIT. TunedIT seems to be very similar to Kaggle. On first inspection one of the TunedIT contests seemed to be very interesting - categorizing the genre and instruments in music. My current area of research involves one dimensional time-series data, so I thought audio would be an interesting domain to work with. Unfortunately, instead of providing the raw audio data, the contest organizers decided to process the audio and provide feature vectors instead. No longer being a one-dimensional temporal problem, the contest has lost much of its appeal.

I have been treating the traffic prediction contest on Kaggle as a one-dimensional temporal prediction problem (considering every road segment as a completely independent problem). I am currently ranked 8th out of 214 teams. I am guessing that my ranking won't improve before the contest end because I don't have any new ideas on how to increase my score. Most of my submissions so far have been used for parameter tuning. However, my parameter tuning efforts seem to have reached a local optimum.

Ambigram Failure

Two people who don't know my name tried to decrypt my ambigram. Their responses were "liynh knoll" and "liymr uwnq". :(

Ambigram

Today I tried to make my first ambigram:
After staring at it for several hours and making minor adjustments, I still have no idea how legible it is. I guess a good test would be to show it to someone who doesn't know my name and see if they can decipher it.

Captcha

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Kaggle

I recently found a great website which hosts competitions related to machine learning. I am currently competing in the freeway travel time contest and the grant proposal contest. I think Kaggle has potential to be very successful. The contest sponsors benefit by getting good solutions to tough problems at a relatively low cost. The contest participants benefit by getting access to interesting problems and the potential of winning cash prizes.

Christmas in Sri Lanka

From left to right: Nathan (dad), Archie (dog), Martha (mom), George (tortoise), Skylor (brother), Aaron (brother), Byron (me).

Al Zimmermann's Programming Contests

Over the last couple of days I have been working on a programming contest called Topswops. I am currently ranked 31 out of 312. This is the third Al Zimmermann programming contest I have competed in. The site has some very interesting optimization problems. In my first two contests I ranked 65 out of 414 and 49 out of 143.

Game Review

I noticed that somebody wrote a review about the laser game I made. The game got quite a bit of traffic when I posted a link to it on Reddit. I am pleased.

Lasers

Thanks to everyone for the useful feedback on my Laser game so far. I have added another three levels, making a total of ten. I am trying to order the levels in increasing difficulty. However, I am having trouble comparing the difficulty of levels (since I already know the solution to levels when I design them, it is hard to judge how hard it would be for someone else to solve them). It would be great if I could get some more feedback on if you encounter an earlier level which appears to be more difficult than a later level.

Batman

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Lasers

My laser reflection game now has seven levels. I have found that it is much easier to create levels for this game than it was for the art gallery problem game. I think the last two levels are quite challenging, so let me know if you manage to beat them.

Lasers

Today I started working on a new Java game. It will be a geometry-based puzzle game. The idea is to position mirrors so that they reflect lasers to a set of targets. I have posted a prototype version here.

State of the Art

For my master's thesis I have been looking into compression-based techniques for classification, clustering, and anomaly detection. I have implemented a classification algorithm using PAQ and evaluated it on three datasets. So far the results look very promising and it seems to get state of the art results on all three datasets. The first dataset (called 20news) involves categorizing newsgroup articles into one of twenty categories. The other two datasets are spam-filtering (ling-spam and PU1). For the spam-filtering datasets a tradeoff can be made between spam/ham misclassification rates. I therefore evaluated my algorithm using ROC curves. Although my algorithm wasn't the best spam-classifier on all portions of the ROC curves, on both datasets there was still a significant portion in which it got state of the art results.

It's Alive!

After the suitcase incident, my desktop has been broken for the last six months. Earlier this week I replaced its motherboard. When I tried booting, I was disappointed to hear that it was still just beeping error codes. However, the error codes this time indicated a memory problem (which is different from the beep codes I was hearing before). I identified the damaged stick of RAM and removed it. Finally my computer seemed to boot normally, except that it unexpectedly turned off about 30 seconds later. I identified this problem to be due to the heatsink not attaching properly to the CPU. I ordered a new heatsink from Ebay and it arrived today. I just put in the new heatsink and the computer seems to be functioning normally. yay. In total, transporting my desktop in a suitcase destroyed the motherboard, one stick of RAM, and the CPU heatsink.

Art Gallery Problem

My art gallery game now has seven levels. Designing challenging levels is surprisingly difficult. Today I implemented mirrors which reflect the guard visibility polygons (seen in the screenshot above). Hopefully mirrors will allow me to create harder levels.

Logarithmic Scales

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Genius

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Art Gallery Problem

I was looking through Wikipedia's list of NP-complete problems to try to come up with an idea for a game. A few of the problems on the list have already been made into games. I thought the art gallery problem might make an interesting game. My research on Google suggests that it has never been adapted into a game before. I spent the day implementing the game and have posted it online here. So far I have only made four levels but I plan on adding more soon.

Google Offer

I just accepted a job offer from Google! The position is Software Engineer. After I finish my master's degree, I will be moving to Mountain View, California.

ACM Eligibility

During the last two weekends I competed in tryouts to be part of the UBC programming team. I did well enough to qualify for the first team. However, yesterday I noticed on the 2010 ACM eligibility chart that I am ineligible because I am slightly too old (by four months). We tried emailing the ICPC manager but she verified that I can not compete :(