Friday, April 29, 2011

face guards by Andrew Winslow, Diane Souvaine and me


A classic problem in computational geometry is the art gallery problem: given an enclosure, how should guards be placed to ensure every location in the enclosure is seen by some guard. In this paper we consider guarding the interior of a simple polyhedron using face guards: guards that roam over an entire interior face of the polyhedron.
Bounds for the number of face guards g that are necessary and sufficient to guard any polyhedron with f faces are given.
We show that for orthogonal polyhedra,

while for general polyhedra

Example of the orthogonal polyhedron:

PDF version of the submitted paper.

Wednesday, April 27, 2011

Chomsky Normal Form for a simple CFG

In case anyone from Comp 170 is interested, here's the Chomsky normal form for the language discussed in class. Note that some definitions of CNF say that you can not put the start symbol S on the right hand side.

Tuesday, April 19, 2011

Creating povray files from Python

A nice recipe from Activestate found here.
Someone added some functionality (added Object) with the description and code found here.

Thursday, April 14, 2011

Service Oriented Architecture links

A collection of links for SOA (mostly from Tisch Library at Tufts:

  1. SOA on wikipedia

  2. Service oriented architecture for dummies

  3. Service oriented architecture field guide for executives

vim - how to resize windows from the command line

:res[ize] -N decrease height of current window by N
:res[ize] +N increase height of current window by N
:vertical res[ize] -Ndecrease width of current window by N
:vertical res[ize] -Nincrease width of current window by N