All entries for Wednesday 12 October 2005

October 12, 2005

Latent Semantic Analysis

I am allergic to jargon! It can be used to

  • conceal the lack of substance or meaning in an idea

  • inflate the commonplace or trivial

  • exclude the unititiated

  • confer pseudo-scientific authority and claim false superiority

So what about Latent Semantic Analysis and its inevitable contraction to LSA? I came across it in an interesting conversation with Mike Joy about current issues in e-learning and assessment. LSA is a statistical method designed to measure the commonality of meaning in a collection of text passages or documents. It compares the frequency of significant words, numerically conflates their meanings, applies some mathematical jiggery-pokery to the data (viewed as sparse matrices), and comes up with some numbers that may indicate how close the texts are in meaning. It can be used as an alternative to the more familiar comparison of strings (a la Google) in detecting likely plagiarism. I believe that it is used effectively in monitoring plagiarism in program source code submitted for assessment by students in the Department of Computer Science.

Clearly jargon is both necessary and useful to experts, and LSA meets this test. It also has the virtue of meaning what it says: the analysis of hidden meaning. It might be interesting to run LSA on this and other blogs on plagiarism!

Isaac would probably not have blogged it

There are many posters around the Warwick campus claiming that Isaac, Albert and Co "would have blogged it" (part of an eye-catching campaign which I seem to have succumbed to). However, all the evidence suggests that Newton was a very private person, secretive about his scientific acitivites, possessive of his creative priority, and at times almost paranoic about his rivals. Historians! Correct me if I am wrong.

Seduce them with style

Writing about web page

Have a look at this elegant example of an "interactive self-assessment quiz" written in the Flash-based software QWriter (click the URL above). I'd take this test again and again just for the pleasure of experiencing its cool and stylish interface. It offers a wide range of question types, presents mathematics well and shows its scientific paces from GCSE to University level in this Chemistry test.

What is not clear is how much effort went into authoring this example; I suspect you need to be an academic chemist and a graphics wiz who can write Actionscipt to produce something like this. I want to find out more. Watch this blog.

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