. . .

I love deadlines ---
I love the whooshing sound they make as they fly by.
Douglas Adams

I'm working on a paper that uses a hybrid (discrete and continuous) model of a generic water revitalization system to develop and test new measures of system resilience to component level faults. One key idea is that resilience is a dynamic property of the system that cannot be understood in terms of the fault probalities or MTBF (mean time before failure) of individual system components. I've been working on these ideas on and off for a couple of years, starting with a small award from the Director's Discretionary Fund when I was working as a contractor at the NASA Ames Research Center.

One novel method of measuring resilience that we developed estimated the transition probabilities of a Markov chain on the two states "nominal -- demand for clean water met" and "performance failure -- demand for clean water not met" and used the ratio of those parameters as a measure of resilience. Paper available.

The current paper will take a broader view of competing ways to measuring resilience. It's titled: "Alternative Metrics for Evaluating the Resilience of Advanced Life Support Systems" Ann Maria Bell, Orbital Sciences Corporation; Richard Dearden, Research Institute for Advanced Computer Science; Julie A. Levri, NASA Ames Research Center. Abstract:

Ensuring the safety of the crew is a key performance requirement of a life support system. However, a number of conceptual and practical difficulties arise when devising metrics to concretely measure the ability of a life support system to maintain critical functions in the presence of anticipated and unanticipated faults. Resilience is a dynamic property of a life support system that depends on the complex interactions between faults, controls and system hardware. We review some of the approaches to understanding the robustness or resilience of complex systems being developed in diverse fields such as ecology, software engineering and cell biology and discuss their applicability to regenerative life support systems. We also consider how approaches to measuring resilience vary depending on system design choices such as the definition and choice of the nominal operating regime. Finally, we explore data collection and implementation issues such as the key differences between the instantaneous or conditional and average or overall measures of resilience. Extensive simulation of a hybrid computational model of a water revitalization subsystem (WRS) with probabilistic, component-level faults provides data about off-nominal behavior of the system. The data are used to consider alternative measures of resilience as predictors of the system?s ability to recover from component-level faults.

So far so good, now all I need is a paper to go with the abstract.

The deadline for submitting the first draft of the paper was March 7.

. . .

Today the Lysistrata Project is coordinating over 1000 readings of Aristophanes anti-war play Lysistrata in 59 countries. I'm planning on attending a reading here in Madison, WI.

Yesterday's blog-O-rama has an update on what's going on at Rivendell, the housing cooperative that I live in.

The proposed settlement of a class action suit that accused record companies of price fixing includes a possible 5-20$ payment for anyone who claims to have purchased a prerecorded cd between 1995 and 2000. The amount of the award to each individual depends negatively on the total number of claimants.

The deadline to file a claim online is Monday March 3, it doesn't take long but you have to provide your date of birth and the last four digits of your social security number. The website to file a claim is:

http://www.musiccdsettlement.com/english/default.htm

This appeared on slashdot back in January, but the discussion was pretty feeble.

"Depressing as it is to acknowledge, it now seems clear we are witnessing the tantrum of a woefully untutored and inexperienced president whose willfulness rises in direct proportion to his inability to comprehend a world too complex for his grasp."

Robert Scheer

Swami Beyondananda has given his "State of The Universe" address for 2003:

Meanwhile ... the issue facing the United States, and indeed the world is, will George Bush give in to his Big Iraq Attack and order up a war? Latest reports say that a war to force a regime change in Iraq will cost $200 billion. It is puzzling to me why some of those fiscal fitness fanatics in the Republican Party haven't tried to find a cheaper way to do it. Maybe if they offered the Iraqis half -- $100 billion -- they could do it themselves.

Then we'd still have $100 billion left to spend on regime change in this country.

Because -- and I have to be blunt here -- the folks we have in charge are fossils fueled by fossil fuels. And in the reptilian brain, problems aren't solved, they're attacked.

read the full address, it's quite funny.

Sweet --- my question about sending a message back in time to your 12 year old self got posted on /. and generated a lot of interesting (& hilarious) comments. It's interesting that despite the large number of comments relatively few threads developed -- the overwhelming majority were replies to the original post.

CleverNickName (aka Wil Wheaton) linked to the /. post from his website WWDN and got some interesting responses as well.

Looking back over my submission, I see that I didn't answer the question myself. Probably because I still don't know what I'd say, despite asking other people this question for years. I suppose my one piece of practical advice would have to be: "don't even think about getting on your bike without a helmet." I'll take a whack at a long answer in my blog one of these days.

Thanks to all who responded.

Updates to my blog:

find out who's leading the weenie patrol --- blog entry 16.02.03

an experiment to test the 'panspermia hypothesis' that was aboard Columbia, the classic science fiction movie "The Day the Earth Stood Still," and the current political climate in the US --- all in the same blog entry 13.02.03

I got some very interesting and helpful replies to two recent comments, on dealing with bugs in Matlab and OroborOSX in Mac OS X and on why patches to Linux don't seem to cause as many problems as patches to some MS programs like MS SQL. Thanks to everyone who took the time to respond --- it didn't seem to make sense to reply to each one individually, but I did go and add all of the posters to my 'friends' list.

And while I was at it, I decided to add all of my fans to my 'friends' list as well --- even the dubiously nicknamed "smelly jeffrey." Actually it doesn't matter to me if jeffrey smells--- I have no sense of smell due to a head injury. (My unsolicited advice to the entire universe: if you ride a bike, wear a bicycle helmet.)

I update my blog regularly, so if you're interested in being my "instant friend" or listening to me rant about the weather in wisconsin, the functioning of my old G3 laptop, the impending war on Iraq, etc., check out:

blog-O-rama