Cheap Power Supplies Are Cheap

March 16th, 2014

When the power supply for my old laptop died a few months ago, I didn't want to spend the $70 that Dell wanted for a new one so I bought a cheap $20 one off Amazon. This promptly broke after a couple of months of use. It stopped charging my laptop but the battery didn't discharge while it was plugged in, so I wasn't bothered that much since I mostly use the computer when it's plugged in anyway.

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Installing Arch on an Encrypted Hard Drive

February 24th, 2014

The Arch logo.

I got a new laptop last week and I thought I'd try out Arch since I've been getting a little bored with the Debian universe lately. My old laptop had CrunchBang on it, which was fun to play around with and very fast but I thought I'd challenge myself and try something that wasn't based on Debian.

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Syntax Trees for Mathematical Expressions

October 21st, 2013

I got bored on Saturday afternoon so I decided to sit down and write a program that would use a neural network to automatically organize my video collection, renaming files with names like The.Conversation.1974.720p.BluRay.x264-AMiABLE [PublicHD] to something more readable like The Conversation (1974). This is my life…

Anyway, I didn't (still don't) know much of anything about neural networks, so I read some words about them and about genetic algorithms. In doing so, I ended up completing this exercise that uses a genetic algorithm to find a sequence of digits and operators that yields a certain target number. The problem I had was that his examples all parsed the sequences from left to right, ignoring order of operations (e.g. 6+5*4/2+1 = 23 instead of 17). I thought it would be fun to try to actually get the right result from these expressions, so I set out to write a simple parser for them.

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Why is Google Translate So Bad?

September 15th, 2013

I saw this post on Reddit this afternoon and it reminded me how terrible Google Translate generally is. Here's the image: Google Translate's interpretation of the numbers 1 through 9. Someone in the comments also linked to Translation Party, which translates between English and Japanese until the same thing comes out twice. It shows a lot of interesting problems with the model that Google uses to do translations. This one came off of a bottle of Rain-X I had lying around.

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Using Subversion through a Firewall

August 12th, 2013

I have been asked by a few different people I work with how to access our Subversion repository through a firewall, so I thought I'd record my solution here in case I'm ever asked again.

My university has a firewall that blocks all incoming connections. There's a VPN system we can use that requires some terrible software that's a pain to set up and there is one server that we have SSH access to from outside the university. I'm sure the IT department really likes its firewall, but it's really inconvenient for those of us who have our own computer systems that are now inaccessible from the internet. My research group has a subversion repository that's located on a computer of ours behind this firewall. It's very handy if I'm on-campus, but if I'm at home or in a hotel or something, I can't get to my work if I forgot to bring it with me or if I want to check in a quick change. I've changed some of the hostnames, but this is basically what the network topology looks like:

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