./backlog: Charlie's blog

meanderings through tidbits of mathsy computery stuff


I had an idea while getting into my car at lunchtime today - what if you could modify your car to add keyless entry? This idea only really struck me because I’d misplaced my keys, but hey - an idea is an idea, so I ran with it. I thought about plugging a Bluetooth shield into an Arduino and running it from the car’s internal electronics (most cars have a cigarette lighter which provide 12v output - and they usually contain enough juice to run a small Arduino circuit for a few months at a time).

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The Phantom Email "J"

Since I started working at my internship placement this year, I’ve noticed a fairly frequent occurrence of a phenomenon where for some odd reason (and seemingly out of context) a phantom "J" character would appear in an email at the end of a sentence. Take this (fabricated, but representative) example: Hi all, There is cake downstairs if anyone wants some. J Bob Anyhoo, with a bit of Googling, I found this blog post which explains the reason behind the phantom J.

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"XMLHttpRequest" is Silly

Here’s something that’s been irritating me lately - Javascript’s XMLHttpRequest function. I don’t normally spend a great deal of time doing web development, but as part of a project at work I’ve been using the Google Maps API to develop a web application to visualise some mapping data. Developing applications using the Google Maps JavaScript API is great - the API is easy to use, the documentation is well written, it’s consistent and everything’s well named.

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Optimising the Fibonacci Sequence with Generators

So recently, a friend of mine was talking about ways of calculating the sum of the first n numbers in the Fibonacci sequence, and it gave me an idea. The Fibonacci sequence is very well known, and it’s an interesting construct - both mathematically and computationally. As well as commonly being taught in mathematics classes as a simple introduction to sequences, the Fibonacci sequence is often used as a method for introducing beginner programmers to the principle of recursion.

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Testing the Monty Hall Paradox

So today I watched the Mythbusters episode that discussed the "Monty Hall paradox" - the infamous probability problem. The Monty Hall paradox is well-known enough that I’ve come across before during maths lessons in school, in probability and statistics textbooks, in lectures, on TV, and so on. This particular Mythbusters episode was testing the hypothesis that contestants who "switched" their choice were twice as likely to win. Mythbusters is well known for "bad science" - that is (amongst other things), biased test conditions, contrived experiments, low sample sizes and so on.

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