December 21st

[edit] Polish Notation

On this day in 1878, Polish mathematician and logician Jan Łukasiewicz was born. In the 1920's he developed Polish notation, a way of writing mathematical expressions without parenthesis -- essentially the invention of the computer "stack." The stack was first implemented in hardware by Charles Hamblin (1963). And in HP calculators as "Reverse" Polish notation (RPN) in the late 60's without digital integrated circuits.

rpn.jpg

[edit] Crossword Puzzles

Also on this day in 1913, the New York World published the first crossword puzzle, by inventor Arthur Wynne.

At first glance, the crossword puzzle seems as if it would be difficult for a computer to solve, and would make a good Turing test -- because it requires knowledge about the meaning of words, puns, etc.

However, it seems a program called WebCrow, uses a Web search engine to attack the problem quite well -- it's even won a tournament for bilingual crossword puzzle solving (English/Italian). The WebCrow website has a neat flash demo that explains how it wins.

Thank goodness we don't have to worry about Crossword Captcha...

[edit] © 2006, Jorge Monasterio

HP Calculator Image from [1]

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