Calculating entropy with Python.

Fun fact: There is more than one kind of entropy out there.

If you've been through high school chemistry or physics, you might have learned about thermodynamic entropy, which is (roughly speaking) the amount of disorder in a closed system.  Alternatively, and a little more precisely, thermodynamic entropy can be defined as the heat in a volume of space equalizing throughout the volume.  But that's not the kind of entropy that I'm talking about.

Information theory has its own concept of entropy.  One way of explaining information theory is that it's the mathematical study of messages as they travel through …

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Another possible solution to an NP-complete problem?

A couple of days ago a research team comprised of faculty at Nanyang Technological University in Singapore, the University of Southampton in the UK, and IQFR-CSIC in Madrid, Spain published a paper containing a creative solution to a problem known to be NP-complete, namely a version of the traveling salesman problem. The TSP, in summary, postulates a scenario in which you have an arbitrary number of towns spread over a large area and an arbitrary number of paths connecting them. What is the shortest possible path one can take in which the traveler visits each town only once and returns …

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Prime Minister of England formally apologizes to the memory of Alan Matheson Turing.

For many years, Alan Turing was one of the lesser-known heroes of World War II. Born in 1912, he rose to prominence at Cambridge in the early 1930’s where he was eventually elected a fellow of the King’s College. Much of his work on computability, or whether or not a problem can be solved and the most effective methods of going about it if it can, is now considered 101-level stuff in comp.sci programs around the world. At the time, however, this work was revolutionary. Turing is best known for the hypothetical Turing Machine, a computing device …

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WPA/TKIP partially broken?

Just when you thought it was safe to raise an antenna and go wireless again, along comes another attack to make you think twice. A pair of security researchers, Erik Tews and Martin Beck, will present a new attack against WPA (Wi-Fi Protected Access) at the PacSec conference next week. If you're not up on wireless network technologies, WPA is the system developed to secure wireless network traffic after WEP was found to be too insecure. The basic purpose of WPA is to encrypt all data traffic between a wireless client and an access point (modulo the control packets, of …

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