Saturday, June 24, 2006

Prof. Keith Decker, loosely coupled distributed autonomous systems

While at BBN, I sometimes worked with the Cougaar team to explore distributed system design as it related to complex logistics problems. Since Hurricane Katrina, I've often wondered if Cougaar could be used to model disaster response in a real-time context. As a CAP responder, I also think about the use of computers to improve search & rescue activity.

Now along comes this ACM TechNews article, referencing Prof. Keith Decker's work on loosely coupled distributed autonomous systems. See also the Univ. of Delaware press release. I'm very glad to see that Prof. Decker is specifically working to improve the ability of organizations to adapt their plans successfully to real-time events (such as Katrina) and constraints (e.g., bureaucracy and physical limitations).

Monday, May 22, 2006


Recently on Mac OS X I've transitioned my Berkeley DB, Graphviz, Hugs, MySQL, Octave, Perl, PHP, PostgreSQL, Python, SBCL and TeX installations to the Darwinports port package management system. On the whole, maintenance has become easier.

Wednesday, March 29, 2006

Tuesday, March 28, 2006

maybe I should switch to FreeBSD or ubuntu...

I just upgraded one of my systems from FC4 to FC5. Now I can't login to the console except in failsafe mode. When I ssh into the system, I see:

$ ls
ls: error while loading shared libraries: cannot open shared object file: No such file or directory

I figured out what was wrong today (5/22):

I had this in my ~/.bash_profile from some much earlier Java installation:

export LD_ASSUME_KERNEL=2.2.5

I commented out that line with LD_ASSUME_KERNEL, which apparently is no longer supported, and that fixed everything.

Monday, March 27, 2006

MacQTeX for online math quizzes

Macquarie University in Sydney, Australia has created some neat software for doing math quizzes online using MacQTeX with embedded Javascript in PDFs.

After FC5 upgrade, yum update stopped working

After I upgraded my GNU/Linux system from FC4 to FC5, yum update stopped working. This is now fixed.

yum couldn't find repositories, it couldn't read repomd.xml files, it really couldn't do anything at all. Firefox would load a repomd.xml off the net just fine, but wget would act as though the file didn't exist.

I traced the problem (in my case) to /etc/nsswitch.conf:

< hosts: files nisplus dns
> hosts: files dns

Saturday, March 25, 2006

Why this blog

I started this blog so I could respond to something Mike Olson wrote at