Archive for the ‘Uncategorized’ Category

(Rated) PG-13 for Ugly Cast

December 2, 2011

PG-13 for Ugly Cast is a blog created and maintained by my son, Ben.  I encourage you to check it out.  It’s very funny.  If you like it, tell a friend.

The title of the blog is an illustration of how he begins his reviews movies.  It means that the movie received an MPAA rating of PG-13 because its cast is ugly. Ben describes the purpose of his blog as follows:

Are we a nation of cowards?

February 25, 2009

Eric Holder said “In things racial we have always been . . . essentially a nation of cowards” because “average Americans simply do not talk enough with each other about race.”

Eric Holder chose an unnecessarily provocative term, and the media (and anyone who doesn’t like Obama, including Jeff Jacoby) went after Holder as an easy target. But I think Holder was making a simple and true point, which I will paraphrase as follows: “An average American feels uncomfortable about having honest discussions about race with an American of a different race, and therefore avoids these discussions.” This paraphrased comment reflects a tendency of many to avoid uncomfortable conversations, and not a universal truth or a judgment.

The storm of protest over his comments is further evidence that too many Americans spend too much of their mental energy reacting to very mild insults that they can feel aggrieved about.  By the way, there are many Americans who would be very insulted by this remark about how easily they are offended by very mild insults.  But they probably wouldn’t share this with me because they are cowards   🙂

Colored letters, labeled dice: a logic puzzle

February 17, 2009

My daughter Jenn bough a puzzle book, and showed me a cute puzzle.  There are 13 words as follows:  BUOY, CAVE, CELT, FLUB, FORK, HEMP, JUDY, JUNK, LIMN, QUIP, SWAG, VISA, WISH.

There are 24 different letters that appear in the 13 words.  The question is:  can one assign the 24 letters to 4 different cubes so that the four letters of each word appears on different cubes.  (There is one letter from each word on each cube.)  It might be fun for you to try it.  I’ll give a small hint at the end of this post. The puzzle was created by Humphrey Dudley.

This problem is also a graph coloring problem.  There are 24 vertices, one for each letter.  Two vertices are adjacent if there is a word containing the two letters.  The puzzle is equivalent to assigning one of four colors to each letter so that adjacent vertices have different colors.

It can also be expressed as an integer program with variables x(i, j) for i = 1 to 24 and j = 1 to 4.  If anyone wants to write an Excel spreadsheet and solve it via integer programming, please let me know.  I’d be happy to post the Excel spreadsheet if you send it to me, or link to it if you post it and send me the URL.  My e-mail address is jorlin at mit dot edu.

Here is the small hint.  five of the words contain a “U”.  The way I solved the puzzle was to focus first on the cube containing the U.  Once that cube is determined, the second cube is much easier.  And once the second cube is determined, the last two cubes are very straightforward.  Determining the last two cubes reduces to recognizing the two parts of a bipartite graph.

By the way, we didn’t time it, but I think Jenn solved it faster than I did, and she used a different approach.

Mike Trick and INFORMS Resources

February 16, 2009

One of the greatest successes of INFORMS over the past 15 years has been Mike Trick’s OR web page, followed by INFORMS on Line and including INFORMS OR/MS Resources.  These have all been labors of love, and incredibly valuable to the OR Community.  Mike deserves at least three rounds of applause and perhaps many more.

Mike has now developed a way of using Google customizable search engine to develop a search engine for OR Resources.  Check it out.

Here is his post describing it.  

I was the one who pointed out Google’s capability to customize web search.  I was happy to play a role in keeping INFORMS OR/MS resources future successes.

Introduction

December 18, 2008

I am a professor at M.I.T.  Both friends and family suggested that I would enjoy doing a blog.  I hope that they are right.