Wielding Supercomputers To Make High-Stakes Predictions 65
aarondubrow writes "The emergence of the uncertainty quantification field was initially spurred in the mid-1990s by the federal government's desire to use computer models to predict the reliability of nuclear weapons. Since then, the toll of high-stake events that could potentially have been better anticipated if improved predictive computer models had been available — like the Columbia disaster, Hurricane Katrina and the World Trade Center collapse after the 9/11 terrorist attacks — has catapulted research on uncertainty quantification to the scientific and engineering forefronts." (Read this with your Texas propaganda filter turned to High.)
"Texas propaganda filter"???? (Score:3, Insightful)
Chaotic Systems (Score:3, Insightful)
Some things can be well-modeled by using good input data and fine-grained analysis, which may require supercomputers.
A problem arises when inherently chaotic (in the mathematical sense) systems are modeled. No amount of computing power will improve the quality of the results.
It may be hard to know what type of system you are dealing with.
And by definition, black swans cannot be modeled at all.
Predictions are only as good as the models... (Score:4, Insightful)
The only way to validate the model is to apply it and see if it works. The problem with hish risk disasters is that they don't happen all that often so it's hard to validate the model. I mean sure you can special case it to death to get it to predict "the Columbia disaster, Hurricane Katrina and the World Trade Center collapse" but if you special case it too much it loses predictive ability for similar but not identical events.
The reason there is so much "uncertainty" (not for me but many others) around climate change is that it is practically a singular event that'll occur 50-100 years in the future. Of course the models can be validated as we go but how much validation is enough? When it's too late?
Scepticism... (Score:5, Insightful)
I like supercomputers in the same way I like architectural monuments - there's an element of beauty in stretching technology to ever more extreme goals, but I'm far from convinced that there's an objective, practical, point to any of the calculations they make.
I'm very sceptical about climate change prediction - because, without any calculation, it's blindingly obvious that climate will change (all evidence suggests vast changes throughout history) and - because mankind is significant among life on earth - obviously we should assume a fair chunk to be 'man made'. I seldom see the questions that matter addressed... for example, in what ways can we expect climate change to be beneficial to mankind? When we ask the wrong questions, no matter how large-scale or accurate our computation, it will be worthless. Don't get me wrong, I see immense value in forecasting... but I don't see available computational power as a limiting factor... in my opinion there are two critical issues for forecasting: (1) collecting relevant data accurately; (2) establishing the right kind of summaries and models. While some models are computationally expensive - in my opinion - the reason for attempting to brute-force these models has far less to do with objective research and far more to do with political will to have a concrete answer irrespective of its relevance... The complexity of extensive computation is exploited to lend an air of credibility, in most cases, IMHO.
"Don't worry about the future. Or worry, but know that worrying is as effective as trying to solve an algebra equation by chewing bubble gum. The real troubles in your life are apt to be things that never crossed your worried mind, the kind that blindside you at 4 p.m. on some idle Tuesday."
The reason is simple: avoidable disasters occur not because we haven't done enough calculations - but because the calculations we do are done for the wrong reasons and produce irrelevant results. If we want to move forwards, we need more observation and more intelligent consideration. Iterating existing formulas beyond the extent possible with off-the-shelf technology, IMHO, is unlikely to yield anything significant.