Wednesday, April 16, 2014

(Nil)Potent problems

Somehow, every year about this time, I start thinking about preliminary exams. (Also known at other institutions as subject exams, qualifying exams, etc.: the dreaded first hurdle of staying in grad school.) Specifically, I start thinking about questions that would be appropriate to ask on such exams, in difficulty, length, and subject matter.

Now, I'm going to avoid my usual rant about the content of most prelims in algebra -- this post isn't about prelims per se, and besides that, the problem I want to talk about is one that I emphatically wish algebra prelims wouldn't test! But it's a fun little argument nevertheless.

Tuesday, February 25, 2014

Today in features, not bugs

The House GOP: :
The proposal, which Republicans voted for in the House Ways and Means Committee earlier this month, would alter the definition of full time employment under the Affordable Care Act from 30 hours a week to 40 hours a week and exempt more businesses from penalties for not offering employer-based insurance or lower the overall penalty burden. Under existing law, employers with more than 50 workers pay a penalty if their full-time employees (defined as working an average of 30 hours a week) receive subsidized coverage in the law’s health care exchanges. CBO concluded that the GOP proposal would lead to the very same problems Republicans have identified in Obamacare. H.R.2575 would reduce the number of people receiving employment-based coverage by 1 million, increase “the number of people obtaining coverage through Medicaid” or the health care exchanges by between 500,000 and 1 million, and raise the budget deficits by $73.7 billion. The ranks of the uninsured would also grow by “less than 500,000 people.”

Until the Republican Party learns to choose their desired policy outcomes first and structure their legislation around achieving those outcomes, no one has any business voting for them at any level.

Sunday, February 23, 2014

To-Read list, Harlem Renaissance edition

I have to confess a deep ignorance of even the canonical works of the Harlem Renaissance; somehow, the curators of my educational experience skipped that chapter of American letters. And it's my own damn fault for not deciding to work through even one of these books in the last five years, or (even worse) during the three before that, when I was actually working in Harlem!

I will say that my leisure reading patterns have more broadly been what I think of as "light", which of course matches no one else's understanding of that term. Leaving entirely aside the math books that I've read for fun, I've chewed through everything Iain Banks has written that I can get my hands on, most of A Song of Ice and Fire (I had to return A Dance with Dragons to the library before I finished it -- no, seriously, someone recalled it out from under me), some Salman Rushdie, and also some nonfiction too. But it's certainly happened that I've taken out a book and gotten bogged down early, not because I wasn't enjoying it, but because it required my full faculties and I was reading for diversion rather than self-improvement.

So I've been wanting to change the face of my to-think list, and I think the end of my Ph.D. and the concomitant life changes should enable that, if I'm serious. So I'm glad to run across this recommendation from The Humanist, of two Harlem Renaissance authors, both women, whose work has been unjustly forgotten.

And just in case that link goes offline:
Ann Petry, The Narrows
Ann Petry, The Street
Nella Larsen, Quicksand

Wednesday, February 19, 2014

This is absolutely a bookmark.

A couple of weeks ago, I ran across this service -- I think it was actually an ad, and I never click on ads, but there you have it. The basic idea is that you set up an account for your discretionary spending, get a debit card for that account, and --here's the brilliant part -- the account smoothes out your cash flow and displays an available balance of less than is actually in the account.

Anyway, read through the site, liked the concept, closed the window.

Forgot the name.

And tried to google it today, and no fucking combination of search terms hits. Until finally the same inline ad shows up in my search results.

Tuesday, February 18, 2014

Thursday, February 13, 2014

Oh Slate, you're being igorant again

I didn't stay up last night to finish watching the women's downhill final, but that's OK. It's not a sports movie, it's sports; I'm watching for the thrill of the game, not on the edge of my seat to see if the American someone in particular won.

Anyway, I wake up this morning and find this nonsense on my Facebook feed:
But it’s still weird that the race had to end like this, because the timekeepers know who really won. The official timing for all Olympic events is supervised by the Swatch Group, through its divisions Omega Watches and Swiss Timing... and today Swiss Timing can measure every race in every event with such precision that there should never be any question about who won. The International Luge Federation, for example, times its races down to 1/1000th of a second. So does speedskating. Why can’t the FIS do the same?
Well, it can, and it does. That’s the weird thing. The official FIS rule book for international ski competitions says competitors’ times “must be immediately and automatically sequentially recorded on printed strips to at least the 1/1000th (0.001) precision.” As Bill Pennington reported today in the New York Times, the clock in the official timing booth on the downhill ski slope actually exceeds that standard, measuring skiers’ times to 1/10000th of a second. So even though the women’s downhill was scored as a tie, “in the timing control booth, three people—the head timer, a backup timer and a computer operator—saw who won the race according to the timing data.”
 Incorrect, Justin. At least three people saw the raw numbers assigned by the timing mechanism to the two skiers. But that's not the same thing as seeing who won. And why is that? Because even though the timing booth may record a number with 4 decimal places, does not mean that this number is correct to all those places.

This is something we were all supposed to learn in middle-school or high-school science: that any measuring device in any experiment is reliable within a certain tolerance, but is useless for distinguishing variations smaller than that tolerance. This is known as the "precision" of the instrument. If the instrument reports numbers in decimal notation, one normally distinguishes between those digits which are known to be correct, and those which are uncertain. (If the tolerance within which the equipment can measure is \( \varepsilon \), and \[ 10^{-e} > \varepsilon \geq 10^{-e-1} \]then the digit corresponding to \( 10^{-e} \) is the first uncertain digit.)

Note that the same piece of equipment may have different reliable precision in different experiments. Think about luge: the timing gate is extremely small and the profile of the athlete is very uniform (they're coming in toes-first), so an additional order of magnitude might be warranted. Or maybe, the true tolerance is only half of the true tolerance for skiing, but that's still enough to warrant one fewer digit in the official time.

Think about it this way: the FIS' decision to truncate to two decimal places means that, in their judgement, it is possible for the timing mechanism to report skier A's time as X.035 and skier B's time as X.037, while skier B actually made it down the course in less time. This is not an absurd judgement, and awarding these skiers a tie is actually more scientifically literate than pushing for the ghost in the Swatch machine.

Tuesday, January 28, 2014

Liveblogging the Veritas Forum

21:30 And we're done. I think two things kinda say it all: more of the audience questions were appropriate for a preacher than for a scientist; and the book table on the lobby was packed with every desperate attempt to make theism intellectually respectable published in the last twenty years. Veritas indeed.

21:25 I made my way to the mike line and asked about personhood being an emergent phenomenon. In particular, since she had gone out of her way to dismiss the very idea in less than a sentence, my question is, do you have the scientific basis for such a rejection? Result: total deflection. I mean, yes, it's also interesting that other humans ascribe person-ness to dumb routines, which is why the Turing Test is less powerful than it first appears, but answer the damn question.

20:58 Did she just approvingly mention Killing Jesus? As in, Bill Fucking O'Reilly?

20:50 Oh, and apparently the Bible instructs us not to self-promote. Or at least not to do the research you already did last year.

20:45  Now Picard and Spickard are sitting down for Q&A. His first questions are about religion.

20:37 ...And she came from an "atheist faith" to a Christian faith. Lovely.

20:36 Ah, now we see the reveal. Imagine an alien race which stumbles across inductions for building a radio. Lo and behold, it's more than its components: there's music too! And it's an emergent phenomenon! Personhood is analogous to the music "emerging" from a radio.

20:29 We've now seen two going on three multimedia clips; yet for some reason the products didn't bother to figure out how to connect the laptop's sound to the PA.

20:13 Picard opens by polling the room about their beliefs on whether human beings are "just" machines. She says she used to. Very few in the audience raise their hands. (The room, by the way, is FULL.)

20:11 A student brings the room to order. Picard's research sounds well worth doing.

The guest of honor: Rosalind Picard of MIT.

The local host: Anderson Spickard. The Third. Captain, I detect no warning signs of incipient douchebaggery.