659 karma · joined September 21, 2007
From 2011-2015, I was a senior research scientist at Disney Research, working on AI and machine learning. From 1998-2011, I was in the Algorithms group at Mitsubishi Electric Research Labs (MERL), where my last job title was distinguished research scientist. The focus of my work was probabilistic inference algorithms, and their applications in communications, signal processing, and AI.
I worked at Viaweb (which is relevant to Hacker News because that's the company Paul Graham co-founded) for one year before joining MERL in 1998. Before that, I was a professional chess player and teacher, and before that I was a theoretical physicist (Ph.D., Physics, Princeton 1990; Harvard Society of Fellows, 1990-93).
You can learn more about me and my interests at my (now inactive) blog at http://nerdwisdom.com, or at http://jonathanyedidia.wordpress.com.
It maintains trees of examples that let it train and respond to test queries in logarithmic time with the number of stored examples, which can be much less than the overall number of training samples. It thus maintains k-NN's property of very fast training time, and is also an online algorithm, and can be used for regression problems as well as classification.
See our paper that was presented at AAAI 2015 here: http://www.disneyresearch.com/publication/the-boundary-fores...
At first, it seemed to me like Coursera, Udacity and EdX offered similar quality courses. But at this point, I think that, on average, the EdX ones tend to be significantly better. And that difference does seem to me to be related to the fact that EdX is not a for-profit institution trying to extract money from you. Also keep in mind that the EdX systems were largely developed at MIT, and EdX was originally intended as the improved version of OCW.
The above information is based on a quick Google search.
Of course, there are advantages of Literate's output compared with CWEB's; it's more flexible in that you can embed arbitrary HTML in the output, so you can easily put images into your explanations, and you can put as many code blocks and text blocks as you like in each paragraph.
Longer articles have many advantages in allowing for a more in-depth explanation, and it is certainly not the case that every reader wants papers shoe-horned into an artificial page limit.
So the thing making people speculate the Patriots cheated is that the Colts' balls didn't deflate, combined with a lack of understanding of the ideal gas law, or a refusal to take it into account.
I take it as a given that the ideal gas law holds. That means that for the Colts' balls not to deflate when going from indoors to outdoors they must have prepared them differently than the Patriots. A simple explanation is that the gas inside their balls had already equilibrated to the outdoors temperatures before the balls were given to the refs (e.g. the Colts threw them around outside). It is speculation, but it seems to me more reasonable than the assumption that the Patriots' and Colts' balls both managed to evade the workings of the ideal gas law, and the Patriots' balls deflated because the Patriots cheated.
The "evidence" for my explanation is the ideal gas law and what Belichick said his team did in his press conference today. If the Patriots followed that procedure, which there is no reason to believe they didn't, and which is legal, one expects from the ideal gas law that their balls would seem under-inflated at half-time. It's basic physics and easy to understand theoretically and reproduce experimentally.
My speculation for what the Colts did rests on the reports that their balls did not deflate. For that to hold, given the laws of physics, something like the balls equilibrating to the outdoors temperatures before giving them to the refs must have happened.
Many people are speculating that the Patriots cheated on no grounds except that the balls deflated when taken outdoors, which is exactly what you expect from the laws of physics.
By the way, about why the Colts balls didn't deflate: the BC professor says they may have over-inflated them, but I think a simpler explanation is that if the Colts prepared their balls outdoors and they equilibrated to outdoors temperatures before giving them to the refs, you would not expect them to deflate. Watch Belichick's press conference today, with an understanding of the ideal gas law, and the fact that working in a ball will also increase the temperature of the gas inside it, and it becomes obvious that if they followed the legal procedure Belichick claimed they followed, the Patriots did not cheat, unless you think having your footballs obey the ideal gas law is cheating.
"Your explanation isn't supported by the data": I wasn't trying to give an explanation supported by the data. I was trying to give an explanation for the data that makes sense and is supported by observing the Patriots play.
It's like saying Magnus Carlsen must cheat at chess, because the chance of him making so few errors is effectively zero assuming he makes errors at the rate that other grandmasters do.