Today I discovered pybliographer, a decent (if not perfect) BibTeX management tool. Surprisingly, Ubuntu had a package for it already (as does Fedora and Mandrake I think), so it was a breeze (-y badger?) to install. I think I might just start maintaining a huge single BibTeX file and then pull out paper-appropriate subsets as I need them. I’m hoping that they add folders or something to later versions.
When I get my schmancy new Mac laptop I’ll use BibDesk, which looks even better.
I found these on a post-it note from his book Topology. I took the class in spring 2000, which feels like ages ago. He ended up writing me a recommendation letter for grad school, so I suppose I have him to thank for where I am now.
I have more quotes somewhere in my notes for the class, but I have no idea where those are. I have tons of juicy quotes in my probability notes, but those have been AWOL for years, more’s the pity.
Ok, that’s not the best anagram for Opal Mehta, but it’s the best I could do on short notice. I’ve watched the story unfold over the past weeks, starting with the original Harvard Crimson article, and then all the collective handwringing and schadenfreude. On the one hand, I think she’s a dumb kid who was caught and should pay for it, but not for the rest of her life. On the other, she’s 18, and officially an adult, so I guess she should have expected this. But maybe we should spread the blame around to her money-grubbing producers and the “packaging company” that shares the copyright.
I have to admit that I’m baffled by this essay from Sandip Roy. He, tongue in cheek, thanks Viswanathan for proving “that finally we can fail, that we can screw up spectacularly and live to tell the tale.” He then goes into a lengthy standard complaint about upper middle class Indians in the US, the model minority thing, and overachieving and pushy parents. It’s about the system from within the system, and says nothing about class disparity within the South Asian community in the US, the differences between recent versus established immigrants, the Hindu/Muslim gap, or any of that.
In pointing out how Kaavya-gate (as some are calling it) helps disprove the model minority myth by proving that South Asians aren’t all superhuman superachievers, Roy can be seen to reify that stereotype. Implicit in his “not superhuman” claim we can find “but still high-achievers.” That’s too much, I think. His point is that these pushy parents need to find some perspective. But does the Opal Mehta debacle really point that out? I don’t think so — this lacks the kind of Aristotelian tragic ending that would really send the message home. Roy wants to indict the parents with the child. But to do that we would need some anagnoresis (the tragic hero’s recognition of their own flaw) that comes from them. Instead we have some crap about photographic memories and unintentional internalization. No amount of media spectacle will affect the hordes of pushy parents unless the pushiness itself can be unambiguously blamed.
So Roy’s essay seems off-mark to me. But maybe if I have mo phat ale I’ll start to think differently.
The columnist J. Grant Swank, Jr. writes:
Now that the Spanish have decided to take over our national anthem, watch out, America. This is just the start.
The Spanish? As in tapas-eating, sangria-drinking, Gaudi-loving Spanish? It’s almost like a Horatio Hornblower novel, with their talk of “frogs” and “dagos” and 9-pounders.
The more plausible explanation is that we are entering a new era in which “the Spanish” is like “the gay.” Although I’ve only heard of “the gay” in an snide putting-down-homophobes context.
Or maybe conservative commentators are getting hip to internet slang. The National Review will complain about Democratic proposals being “teh suck” and No Child Left Behind as “teh r0xx0r.”
We need a semidefinite article to provide a middle ground between the indefinite and definite. The question is, how would such a semidefinite article look? [There’s a certain answer I’m half-expecting…]
Ever since getting an iPod I’ve spent a significant portion of “commute time” (e.g. to rehearsal on BART) listening to music. I pop in the headphones and (modulo the train rumbling) shut out the world around me. Last night I bought the Chicago Symphony Orchestra (Solti) recording of Verdi’s Requiem (1977 Grammy winner) and popped it in the CD player at home. We’re singing it in June so I figured I would just read along with the score. What struck me immediately was the non-immersiveness of the listening experience. I was acutely aware of the creaking of my chair, the people next door calling their children in from the backyard, and innumerable other distractions.
The iPod made me lazy, I decided. While you do hear all of the music with the earbuds, it’s like it’s being spoon-fed to you and it’s easy to not pay attention to it. When I took the composition seminar from John Harbison, he complained about a similar phenomenon with regards to any headphone-listening experience. He said that ears become more closed when the music is that you don’t really hear the fine details. At the time I kind of lumped that comment with the audiophiles who like the “warmness of tube amplifiers,” but now I’m starting to think he was onto something.
And therefore I resolve to listen to more music without headphones. Too bad I have to work in an office with 20 other people all day.
I’ve gone to a number of job talks lately, since the department is interviewing people, which brought up something I’ve been mulling over since I started grad school. I’ve gone to a huge number of engineering talks aimed at “a general audience.” There are levels of generality, from “control theorists not studying distributed control of hybrid dynamical systems” to “people who look at systems engineering” to “electrical engineers” to “engineers” to “technical people” to “layperson.” A shockingly large number of people I’ve seen talk fail to grasp the fineness of these gradations.
One problem is the “intelligence of the group” issue. In order to pitch their talk to a wider audience, the speaker will dumb down a portion of their research or will abstract away some details. In the former case, they obscure their own contribution by making the problem seem easy. If they then go and introduce some complicated algorithm to solve the problem, the audience may wonder why they went to all that effort. In the latter, they often make their problem seem very similar to another problem that is very simple. When pressed on the point they may fumble because it’s easier to abstract away than to put in the details afterwards. Both simplification and abstraction are important to make the material accesible, but I’ve seen many talks run afoul of underestimating the audience’s ability to follow the argument and find the inconsistencies.
Often times speakers mis-focus their attention. I’ve seen this happen in several ways. Sometimes they wrote the talk for some one hour seminar to a more general audience and then tried to give it to a narrower group in less time. Other times they have just one set of slides for all versions of the talk and get bogged down in the beginning. These can be fixed by just making a fresh set of slides for every talk. Slightly less frequently, they feel the problem needs 5 motivating examples in order to get people interested and they spend all the time explaining their examples. This also happens when work is interdisciplinary. For example, do not give a talk to machine learning people by emphasizing all the points that are more of interest to cancer biologists.
The last and most egregious problem, I think, is that speakers do not have an objective to their talk. Maybe it’s the actor in me, but giving a talk is like doing a monologue, and you can’t just get up on stage and read the text of the monologue without pointing every line and without making the whole thing have an overarching objective. The objective of a job talk should be self-evident (although not to everyone, it seems). Conference talks need objectives too. Most importantly, if you have a poster you better have an objective or people will leave while you’re talking, a truly disheartening experience, as I well know.
I’m not saying that giving a talk is easy — it is a piece of theater, and like all pieces of theater it can be amazing, terrible, or “not quite work.” But thinking about all these talks really reminds me that these aren’t things you can just “phone in,” especially if they are about your research. And some people just don’t think about that enough before getting up there.
I was completely bogged down with work so I missed some friends’ Simpsons Math Party in honor of last night’s episode, in which Principal Skinner is removed from his position after a Larry Summers-like incident in which he said girls are bad at math. His replacement divides the school along gender lines — the girls’ half is beautifully landscaped with famous women artists’ works on the walls, and so on. Unfortunately for Lisa, math class is now about how numbers “make you feel.” “Is the number 7 odd, or just different?” asks the teacher, before leading the class in a self-affirmation conga line.
Lisa decides to sneak over to the boys side, which, in typical Simpsons fashion, has been turned into a post-apocalyptic warzone. The boys are savages, running around playing “guns” and drawing robots made of guns blowing up things with guns that shoot guns. The one saving grace for Lisa is that they study real math there. With Marge’s help she dresses as a boy and goes to math class where she (gasp!) actually learns that +5 and -5 are solutions to X2 = 25. When Lisa gets into a playground fight Bart discovers her secret and helps her become more like a boy. Lisa gains acceptance by beating up Ralph and “becoming all that she hates.”
In the end, Lisa wins the prize for best math student and unmasks herself, saying that it proves girls are good at math. Bart responds with the point that it is because she “became a boy” that she could learn the math. As Lisa tries to wend her way through these opposing points the auditorium descends into chaos. As the credits roll we’re treated to Jethro Tull’s masterpiece, Thick As A Brick.
For me, the credits were probably the best part of this episode. While I have to give credit to the show for taking a difficult issue and trying their best to satirize it, it misses the point, I think. To the writers, the public discussion of the Summers case focused too much on him and not on what the underlying problem issue, which is that of mathematics education. Correspondingly, Skinner is disposed of in a matter of minutes (his pandering nature could be another subject of discussion). The new principal, a hard-talking cariacature of a feminist, decries inequity but is uninterested in real reform. The episode kind of moves from there on out in the logic of The Simpsons world. In a way, it all justifies Skinner/Summers, since the most vocal critics are uninterested in the real issue at hand (math).
The issue of gender and learning and whether there are “gendered” school subjects is just brought up at the end of the episode and never addressed! Perhaps to the writers it lampoons itself by its absurdity and we’re supposed to laugh Bart out of the debate, but Lisa takes him seriously and so do a huge number of people. Indeed, the gender-labeling of academic disciplines is probably one of the more harmful effects of our current public education system. When Bart claims that you have to be boy-like to learn math, is this a pointer to the debate we should be having, or just a garnish for the episode? I would argue that the chaos of the “chair-fight” at the end points gives the latter effect — the last thing the show wants is to seriously moralize. But to leave it so ambiguous is a bit dangerous, I think.
What the episode does do is bring up a whole barrel of ideas to play around with and fodder for discussion, so it wasn’t a total wash. Plus, how often do you hear Thick As A Brick on TV?
This is kind of a cop-out, since it’s a two-page “note” rather than a real paper, but since I’m so out of practice of reading and synthesizing papers I think that it’ll be a baby-step back into the swing of things. This paper is another information-theory one, but it uses a more general strategy that is easily explained to a general audience.
A Counterexample to Cover’s 2P Conjecture on Gaussian Feedback Capacity
Young-Han Kim
ArXiV : cs.IT/0511019
Imagine you have a communication channel that can be modeled as:
where X is the input, Y is the output, and Z is a stationary Gaussian process (not necessarily white noise, but possibly shaped with some spectrum). The approach information theory uses is to say that we’ll limit ourselves to a block of n time steps and then pick a set of 2nR sequences of length n that will encode 2nR messages. These sequences are called codewords and R is the rate of the code, measured in bits/time. If you use n = 10 time steps at rate R, you get a total of 10 R bits, which can stand for one of 210 R messages. A coding system for this model picks a set of codewords and a decoder that will take the noisy output Y = X + Z and guess which codeword was sent. Shannon’s Noisy Coding Theorem says that there’s an number C, called the capacity of the channel, such that for any rate R below C, the probabiliy of making a decoding error goes to 0 as the blocklength n goes to infinity.
Of course, you have constrained resources, and in the above Gaussian problem we assume that the power (squared Euclidean norm) of the codewords is constrained to n P. If we fix the noise power as well, the capacity is neatly parameterized in terms of P and we can denote it by C(P). The paper here is about the role of feedback — if the encoder knows exactly what the decoder receives, then picking codewords “in advance” may not be a good idea, since the encoder can adapt what it sends based on “how confused” the decoder is. There’s a longstanding conjecture that feedback can’t improve the actual capacity by more than doubling the effective power, so that CFB(P) is smaller than C(2P).
It turns out this is false, and the scheme used to show it is a modification of an old one by Schalkwijk and Kailath (Transactions on Information Theory, 1966). The intution is that with perfect feedback, the encoder knows exactly what the decoder does, and therefore can mimic the decoder’s operation perfectly. Imagine Alice is talking to Bob, but Alice knows exactly what Bob thinks she is saying. Using this knowledge, she can tailor the next thing she says to correct Bob’s misunderstanding as best she can. Bob will still not quite get it, but will be closer, so Alice can iteratively zoom on the precise meaning until she’s satisfied that Bob has gotten close enough.
Another way of thinking about it is helping someone hang a picture. You can see if the picture is level or not, and you issue commands: “two inches higher on the left,” “one inch on the right,” “half an inch on the left,” “a nudge more on the right,” until it’s hung straight. This is precisely the intuition behind the Schalkwijk-Kailath coding scheme. With this feedback you can get more precise than you could without, and similarly in this Gaussian communication example, you can communicate more bits reliably with feedback than without.
The result is not earth-shattering, since there’s another result that says you can get at most half a bit per unit time with feedback than without. But it’s a nice application of the coding scheme and a cool demonstration of the usefulness of concrete examples.
I’m listening to Don Byron’s album Ivey-Divey, which I picked up from the SF Public Library earlier this week. I’m a bit of a Byron enthusiast, so I tend to view everything the man touches as gold. Part of this is from seeing him at Yoshi’s back when they had student tickets and let people stay from the 8pm set to the 10pm set if the latter hadn’t sold out (Yoshi’s has since become lame and student-unfriendly). Byron’s approach to albums is often that of a curator — works like Bug Music and The Music of Mickey Katz are examinations of eras or genres of music. The former is early Ellington, Raymond Scott, and John Kirby, and is a real delight. The latter is a jazzy klezmer variety act. Other albums take genres and deconstruct them a bit, like This is #6 or (arguably) Nu Blaxploitation. The album Romance With The Unseen is a little more straightahead but features a jaw droppingly beautiful version of the Beatles’ I’ll Follow The Sun with Bill Frisell on guitar.
Ivey-Divey takes a look at a recording session with Lester Young, Nat King Cole, and Buddy Rich. The bass-less combo has a charm and sound all its own (I’ve only heard the original once, but now it looks like I’ll have to buy it). Byron isn’t “doing Lester Young” on this album, however. He places those tunes next to some originals and classic Miles Davis. He has a killer combo — Jack DeJohnette on drums and the monstrously talented (and young) Jason Moran. Better players you couldn’t ask for, and when the chemistry is on and the soloists are quoting each other’s licks you know something’s happening.
It’s easy to complain that the album is stylistically disjointed. You have to remember that Byron is not only the best clarinet player alive, he’s one of those great curators who juxtaposes with intent. So you get a funky tune like “Leopold, Leopold” (you have to know your Bugs Bunny) followed by a Freddy Freeloader that starts out with just the clarinet, singing to itself before being joined by a Monk-like plunkety-plunk and light high-hat taps and slowly working itself into a lumber like Leopold and then flying off somewhere else with Moran’s hypnotic solo.
I can’t believe I didn’t listen to this album until know. What else have I missed out on?
I’m sitting with Amrys in an Espresso Royale in Madison. She’s reading a book before class and I’m trying to clean up a writeup on for my research. Espresso Royale was one of my favorite hangouts in high school, and I was distressed to learn, upon moving to Boston, that it was in fact a chain. But there’s something familiar about the place here beyond the Generic College Coffeehouse thing.
Maybe it’s the glassware or ther furniture, the branding of the place (which only became so coordinated and overt in the late 90’s, I think). It’s a manifestation of a greater sense of “home” that I get here. Maybe all midwest college towns are somehow the same. The snow is falling thick and wet outside, we’re warm in here with our coffees, and 90% of the people in here are working. It’s comforting like my recent sojourn in 1369, but this nostalgia runs farther back, to the days of my purple spiral notebook, Ritz crackers, and Coca-Cola.
An Ergodic Walk 