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Showing posts from December, 2011

Wrong end of the stick

There's a story about air-force scientists during world war 2, that reflects an interesting concept about the things we see and how they can alter our assumptions. The story goes that the allied bombers were suffering great losses during their air-raids of continental europe. The allied scientists got together and anaylsed the damage reports from the engineers tasked with fixing the planes after each raid. (One of the scientists working on these problems was Abraham Wald )

Here is an example of the sort of summary engineering reports they might of been faced with. The report details the parts of the plane and what proportion of aeroplanes had been damaged in that area: (This data is completely made up by me):
15% had damage to 1 or more engines
25% had tail damage
25% had damage to the nose and cockpit area.
35% had damage to the fuselage

The aircraft engineers could only add extra-armour to one part of the plane, any more armour would limit the aeroplane in other ways e.g.: makin…

Testing, Testing, 1, 2, 3.

When I have a spare moment, I usually try and think about how to test something. In fact thats not true, what I do is actually test something. It might be an app on my phone, an online tool, parking-ticket machine or search engine. Usually it is what-ever is to hand, at the time. This is a good way to practice my skills, and can take as long as I have free. In fact having only moments is beneficial, you soon get better at finding out more issues - more quickly.

For example, a few moments ago I thought I'd test Google's currency converter. If you haven't seen it, it looks like this:


You enter a value and two currencies in the format shown, and Google will give you an answer with great precision. (I haven't examined the accuracy.)

Starting from this I varied the text slightly, using "euro" instead of "EUR", also swapping "gbp" and "euro" to see how precedence affected the results. This seemed to behave as expected, but it did make …