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26 June, 2008

"If By a Man's Works Shall We Know Him...

...then you, sir, are a colourful, nine-dimensional blob."

A quote from a colleague. I take it as a compliment. If you can't make pretty graphs, what's the point of science?

EVD


Apologies for my absence - recent days are mostly spent taking tea in a rough-and-ready way while writing up. With a new position starting for me next week (though happily in the same group), my thesis-writing time will be squeezed into evenings and week-ends alone, so I don't see much chance of improvement in the immediate future. Your patience is appreciated!


Toodlepip,

Hobbes

16 comments:

  1. ~ Phyll26 June 2008 at 18:52

    Doughnuts...Yum! :p

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  2. Brent26 June 2008 at 20:01

    Thanks for the update! Good luck with your writing.

    Brent

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  3. Anonymous26 June 2008 at 20:30

    doughnuts with sugar sprinkles..

    what is your theme of research?


    robert

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  4. 小 約翰26 June 2008 at 20:47

    looks kind of Eigen-ish? john

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  5. Hobbes26 June 2008 at 21:30

    Thanks for the good wishes, I really appreciate them. :)

    The general field is variously known as:

    "Artificial Intelligence"
    "Information Engineering"
    "Signal Processing"
    "Machine Learning"
    "Pattern Analysis"
    "Statistical Pattern Recognition"

    ...depending on which department of which institution you're in. Our name is Legion, for we are many. ;)


    Toodlepip,

    Hobbes

    P.s. John, the graph is an Extreme Value Distribution for a three-dimensional Gaussian Mixture Model of three components, with general covariance matrices. If the model represents "normality", it effectively describes where the extreme bounds of "normality" lie, so that you can identify extreme events (stock crashes, aircraft engine problems, patient organ failures, etc.).

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  6. speakfreely26 June 2008 at 22:37

    Sooo..."normality" consists of two orthogonal distorted doughnuts centered around the origin, with an undistorted parallel doughnut in positive space and a more eccentrically distorted parallel doughnut in negative space?

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  7. Hobbes26 June 2008 at 22:45

    Uh-oh, it's CB, better tighten up my loose techspeak. :)

    The image is just a few slices through a four-dimensional blob (contourslice.m in Matlab, if you use it) to give the general impression - of course, a probability distribution defined over 3-D is a 4-D quantity, so it's hard to visualise holistically. I had to slice the lumpy model, so you're looking at a few cross-sections taken at orthogonal axes.

    "Normality" here is a trimodal GMM: three hyperellipsoids that sit within the middle of the doughnuts. Like three American footballs of different stretch and width, fused together into a lumpy bundle. :)


    Toodlepip,

    Hobbes

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  8. speakfreely27 June 2008 at 18:25

    Allright, I'm off to tape 3 footballs together and see if that will help me predict what's going to happen to our crippled economy.

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  9. Si's blog28 June 2008 at 20:58

    If the number of dimensions is the least it takes to locate yourself, need a lot less than that. Can't hardly find where at I am no how with just three (time is an illusion so it does not count).

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  10. Jamus29 June 2008 at 14:27

    All this talk of doughnuts and footballs...by far the most ridiculously beautiful rant I've seen in a very long time.

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  11. Matt29 June 2008 at 17:11

    If one were to send you some samples where could they send them?

    Peace

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  12. Hobbes29 June 2008 at 18:14

    Dear Matt,

    That's very kind of you, thank you. I'm always happy to swap tea-samples. Do please e-mail me (hobbesoxon 'at' gmail 'dot' com), or leave your e-mail address here and I'll contact you.


    Toodlepip,

    Hobbes

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  13. MarshalN4 July 2008 at 04:06

    Aha, you use free photobucket, which has now kicked you out for exceeding your bandwidth. Obviously, you're getting too many hits for your own good :)

    I pony up the money every year for a pro account. It does make photo hosting easier to handle.

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  14. Hobbes4 July 2008 at 07:26

    I considered it, but apparently the Photobucket bandwidth counter resets on the 4th of each month for my account... why is, by sheer coincidence, today. So let's see if all the images return. Fingers crossed.


    Toodlepip,

    Hobbes

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  15. MarshalN4 July 2008 at 21:39

    Indeed, they do

    But your bandwidth usage will only go up, not down :)

    Although, one way to avoid it -- if there's a way for you to reduce the number of posts you show on your blog's first page, then you will reduce your bandwidth usage significantly without needing to pay them. After all, I doubt most of your readers are going 40 days back to read old entires there -- if they really want, they can always go dig it up.

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  16. Hobbes5 July 2008 at 07:37

    That's a clever idea, gracias.

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(and thanks)