Category: Technical

The mathematics of Pan Am contracts

I wrote a mathematical analysis of the bidding process for the security of the Pan Am games (submitted to KES2014 conference):

I found problems with how the bidding score is computed, and the Globe & Mail picked the story.

Though my write up consisted of several pages of math, the Globe & Mail went for the (important) bottom line 🙂 as you can read here:

The price bidders submitted made up 40 per cent of the final score for each finalist. “The money amount was not given a proportionate weight,” suggested Michael Soltys, a professor in McMaster’s computing and software department (Mr. Soltys is also a consultant for a company that is owned by Reilly Security).

Other newspaper stories on the Pan Am bidding process:

MySQL scripts

In order to do a MySQL dump on a remote machine with ssh, one can do it with the following command:

ssh name@URL 'mysqldump -u root dbname -ppasswd > dbname.sql'

This results in the following Warning:

Warning: Using a password on the command line interface can be insecure

In order to avoid it, add the file

~/.my.cnf

in the remote machine home directory, with the lines

[client]
password="passwd"

and change its permissions with

chmod 600 ~/.my.cnf

and use the following command instead:

ssh name@URL 'mysqldump -u root dbname > dbname.sql'

Chrome Sync

One of the nicest features of Chrome is the sync between various devices: Desktop, laptop, iPod, etc. All of them will be synchronized with the same book marks, open tabs, passwords, etc. I had a small glitch that arose as follows: I bought my desktop after my laptop, and I installed my files from the laptop’s Time Machine backup. As a result, the following directory was placed on the desktop machine:

~/Library/Application Support/Google/Chrome

which contains Chrome’s configuration, preferences and caches. Thus, on my desktop Chrome was running with the preferences from my laptop. One of the ways that this manifested itself was that the laptop and the desktop were seen by the Chrome sync process as one and the same. The way to fix it was simple; delete the directory above, and reinstall Chrome. Here is a related post.