Tuesday, 25 November 2014
Thursday, 20 November 2014
(Credit to Rob Planke for helping in fleshing this idea out.)
Kessler syndrome is a problem that we don't have a solution for yet. It refers to case where the flotsam that accumulates in low Earth orbit accumulates to the point where pieces of it collide with each other, thus breaking apart into more pieces, which make more collisions and so on. If this starts to happen on a large scale, there will be too much garbage in that orbit to make anything else up there safe for long, even with how large space is.
As a younger, I had imagined a curved, ruggedized 'sweeper' satellite to knock trash out of orbit by deflecting it downwards and slowing it enough to destabilize the orbit of the trash. But if the satellite were traditionally made or rigid materials, it could make matters worse. Only three satellites have been destroyed in orbit (many more have been deorbited safely), and their remains are now clouds of thousands of pieces of junk. One sweeper would have to pick up thousands of pieces just to break even if collisions were knocking pieces off of it.
...but what if it were made of something more fluid, cohesive and/or deformable? What if most of the parts that could come off of the sweeper would break down in the vacuum and solar wind? A substance based on ballistics gel comes out as a strong candidate. Its density is comparable to water, it's effective at stopping bullets, and it's cheap. Have a look at some of the pictures here:
Now imagine a pancake shaped object composed of that stuff, perhaps with a membrane to reduce premature breakdown and spillage from impacts. It's pancake shaped to maximize collisions for a fixed amount of payload that has to be brought up.
I'm still a bit concerned about the foam leaving the block of gel in these pictures at the entry and exit points of bullets. Even a paint fleck at orbital speeds is dangerous, but foam is likely less dangerous than a stray bolt or wingnut.
Also, to move the pancake toward the orbit of the centre of a cloud of junk, and to and correct for collisions that arise, there is a 'spine' which holds thrusters along the outer edge. The 'spine' also aids in maintaining the pancake shape when a ball is more natural.
With regards to cost and scaling: A disc of ballistic gel two metres across and 10cm thick, and the density of water has a mass of about... 300kg? Plus skin and thrusters. That's running in the region of $500k for just one disc. How many would be needed? Is there a stickier or lighter material that could be used instead? Is space junk clustered enough for a few discs can catch most of it? What are the limits on mass deflected and time in orbit for such a pancake?
This is going to be an ongoing problem for the rest of the space age because of entropy and accidents, so we should practice good orbital hygiene now before things get ugly.
Monday, 17 November 2014
Part of my work at the Institute for the Study of Teaching and Learning in the Disciplines, or ISLTD for short, is to develop a handbook for statistical design and analysis.
The clients of the ISTLD are Simon Fraser University faculty across all disciplines that are looking to incorporate new teaching ideas and methods into their courses. This handbook is intended for faculty and grad student research assistants with little statistical background. As such, the emphasis is on simplicity rather than accuracy.
One wall I've run into in making this document as accessible as possible is terminology. Different fields use different terms for the same statistical ideas and methods. There's also a lot of shorthand that's used, like "correlation" for "Pearson correlation coefficient".
Why is spatial autocorrelation referred to as 'kriging'? Why is spatial covariance described in terms of the 'sill' and the 'nugget'? Because those are the terms that the miners and geologists came up with when they developed it to predict mineral abundance in areas.
Why are explanatory variables still called 'independent variables' in the social sciences even though it causes other mathematical ambiguities? Because they're trying not to imply a causal relationship by using terms like 'explain' and 'response'.
For the sake of general audience readability field specific language will be kept to a minimum, and shortenings will be used whenever a default option is established, as it is with correlation. However, the alternate terms and shortenings will be included and explained in a statistical thesaurus to be included with the handbook.
Here are three pages from the rough draft of that thesaurus. Since such a thesaurus, to my knowledge, has not been published before, I would very much appreciate your input on its readability, or what terms should be included.
Thanks for reading!
Saturday, 8 November 2014
Banff, in terms of climate, and street structure, makes me feel like I'm at an idealized version of home. Home being Prince George first and Smithers second. Moreso Smithers for the size and more prominent mountains, and Prince George because of the greater level of development that comes from the larger tourist income.
The air is sharper than in Vancouver. You can tell it's drier because it doesn't take your heat away even though it's quite cool out, and wisps of your breath show. Visibility is very good, and the rocky hewn face of mount Rundas kilometers away. Looking down from the direction of the mountain, there are alpine style houses with steep peaked rooves and mortar walls. Every shop and building has the same style, with amber treated logs and wood panels framing the shapes of the buildings, as well as the doors, windows, and awnings. Storefront signs carved and painted wood, written in English and Japanese, line the street and tell of sushi and knickknacks for sale. It's early afternoon, but the sun already seems low because of surrounding mountains making the horizon higher than usual..
I wish I could share the feel of Banff with you, but words cut only deep through the umweld. Voice and careful observations may be able to improve that connection.
I wonder if anybody is doing this: high detail, observation based narrations of places, especially tourism places. There are guided meditations which are engrossing narrarions of imaginary generic places like beaches and deserts. There are descriptive audio tracks of television for the vision impaired, which reflect something specific. There are lots of writers that describe imaginary specific places in great detail in text. So is there something out there, preferably in audio format, which describes a real place but takes the time to do so in a high resolution, including the smells and tactile sensations.
I'd like to try it with some of my favourite places in Vancouver like the new west waterfront. It could be a creative project: go down to the waterfront, record audio, take pictures, and make and document observations. Then take all that and turn it into a narration of walking on the boardwalk that someone else could listen to and get, hopefully, a sense as if they had been there to some limited extent. I could incorporate some meditative ideas into it to help people get into an imaginative state.
Wednesday, 5 November 2014
Recently I learned that miraculin, a compound that temporarily alters taste bud receptors, came within a day of being listed by the US FDA as "generally recognized as safe". It had been used before meals in parts of Africa for hundreds of years prior, and without any known cases of related illness.
Then, one day before the safe label was to be given, the FDA decided to treat miraculin as a food additive instead of a food, which barred it from appearing in commercial foods without and additional battery of tests that nobody was prepared to pay for. No reason was given for the change, even after a freedom of information act request.
We live with decision today, and considering obesity related mortality, we die by it too.
If the decision were made today, it seems unlikely that miraculin would have difficulty being listed as a generally safe food ingredient. What's to stop us from reevaluating that decision now by testing miraculin as a food ingredient from scratch? It was never found to be unsafe, so there remains no biological basis for it to not be in foods other than the decisions by men whom have since retired or died.
There are similar legacies scattered through the law, such as in being illegal to wear a mask in a mob, which comes from a law passed more than 100 years ago that nobody had thought to enforce until recently. The legal issues that Tesla Motors currently has getting to market are mostly due to depression era laws pertaining to car dealerships.
This habit of accepting the decisions of the dead is costly. It makes the law more complex than necessary and it hides or hinders ways in which we could improve our society.
I wish there was a think tank of historians whose mission was to dredge up old legal decisions which lack modern relevance. They could bring them to the existing authorities to have them downstruck or updated before they become entangled in modern issues and used for situations that their creators could not have considered in writing the law.
Tuesday, 4 November 2014
In baseball, sabremetrics started a push for batters to hold off for more and better pitches. By 2011 or 2012, strikeout rates were higher than they were in a century, probably in part of the reduced hitting but also due to pitchers throwing more pitches, knowing they would be swung at less often. How long until batters adapt and capitalize on the higher quality pitches they are receiving to increase hit rates and home runs instead of waiting for many pitches?
This is an example of perfect imbalance, as explained in this video by Extra Credits. Players of strategic games that involve a lot of pre game decisions often refer to these decisions and the information leading to them as "the meta game". In MOBA games like League of Legends or fighting games like Smash Bros. or Soul Caliber this amounts to selecting one's avatar character and the bonuses they will bring into the start of a match. In collectible and living card games like Magic: The Gathering and Android: Netrunner the meta game is one's deck building process and the popular types of decks among one's opponents.
The pre game decisions, the meta game, in sports include who to hire and how to train. In sports where game-to-game fatigue is a factor, such as hockey with goalies or baseball with pitchers, the meta also involves choosing who will start the game, and how well that matches against the opposing goalie or pitcher.
The general idea of metagaming is to make choices that counter the likely choices of opponents. Against a learning opponent, this requires constant adaptation.
Consider fashion, where to win is to receive attention, admiration as a consumer and sales as a designer. Fashion is played by wearing/creating an outfit that stands out from that of the existing crowd.
Consider the red queen hypothesis, a biological principle whereby a species succeeds by apadting to its prey predators and competitors. Specifically, the red queen hypothesis is that since all species are doing this, the best a species can hope for is to keep up in evolution, never get ahead.
Sabremetrics got so big as a statistical toolset not simply because it was interesting or novel, but because it was actionable. It provided information that could be converted in decisions, instead of just being elegant or produce a pretty graph.
If hitting in baseball is due for a comeback, might it make sense to load up your farm team with sluggers and curveball pitchers now? Do you reduce your emphasis on stolen bases in anticipation of fewer pitches per at bat?
Would a change from walks and strikeouts to hitting favour franchises that traditionally rely on high scores like Texas, or ones that rely on many small hits like Kansas City?
As always, comments welcome, including those stating I'm wrong about everything.