Linkage : Black Friday edition

This is an amazing video that makes me miss the Bay Area. (via Bobak Nazer)

Also via Bobak, we’re number 8 and 10!

Since it’s holiday season, I figured it’s time to link to some profanity-laden humor about the holidays. For the new, The Hater’s Guide to the Williams-Sonoma Catalog, and the classic It’s Decorative Gourd Season….

A Game of Food Trucks. (via MetaFilter)

Larry Wasserman takes on the Bayesian/Frequentist debate.

LCD Soundsystem + Miles Davis youtube mashup.

My friend Erik, who started the Mystery Brewing Company, has a blog called Top Fermented. He is now starting a podcast, which also has an RSS feed.

Spread spectrum… in spaaaaaaaace…

I saw on the ArXiV earlier this month a paper on interstellar communication by Berkeley’s own David Messerschmitt. I only met him once, really, at my prelim exam oh so many years ago, but I figured I would give it a read. And here you thought spread spectrum was dead…

Prof. Messerschmitt proposes using spread-spectrum because of its combination of interference robustness and detectability. The fundamental assumption is that the receiver doesn’t know too much about the modulation strategy of the transmitter (this is a case of stochastic encoding but deterministic decoding). The choice of wide-band signaling is novel — SETI-related projects have looked for narrowband signals. The bulk of the paper is on what to do at the transmitter:

The focus of this paper is on the choice of a transmitted signal, which directly parallels the receiver’s challenge of anticipating what type of signal to expect. In this we take the perspective of a transmitter designer, because in the absence of explicit coordination it is the transmitter, and the transmitter alone, that chooses the signal. This is significant be- cause the transmitter designer possesses far less information about the receiver’s environment than the receiver designer, due to both distance (tens to hundreds of light-years) and speed-of-light delay (tens to hundreds of years). While the receiver design can and should take into account all relevant characteristics of its local environs and available resources and technology, in terms of the narrower issue of what type of signal to expect the receiver designer must rely exclusively on the perspective of the transmitter designer.

The rest of the paper centers on designing the coding scheme which is robust to any kind of radio-frequency interference (RFI), without assuming any knowledge at the decoder — specific knowledge of the RFI (say, a statistical description) can only enhance detection, but the goal is to be robust against the modeling issues. To get this robustness, he spends a fair bit of time is spent developing isotropic models for noise and coding (which should be familiar to information theorists of a Gaussian disposition) and then reduces the problem to looking for appropriate time and bandwidth parameters.

This is definitely more of a “communication theory” paper, but I think some of the argument could be made clearer by appeals to some things that are known in information theory. In particular, this communication problem is like coding over an AVC; the connection between spread-spectrum techniques and AVCs has been made before by Hughes and Thomas. However, translating Shannon-theoretic ideas from AVCs to concrete modulation schemes is a bit messy, and some kind of translation is needed. This paper doesn’t quite “translate” but it does bring up an interesting communication scenario : what happens when the decoder only has a vague sense of your coding scheme?

QOTD : a lack of “know-what”

From the tail end of The Human Use of Human Beings:

Our papers have been making a great deal of American “know-how” ever since we had the misfortune to discover the atomic bomb. There is one quality more important than “know-how” and we cannot accuse the United States of any undue amount of it. This is “know-what” by which we determine not only how to accomplish our purposes, but what our purposes are to be. I can distinguish between the two by an example. Some years ago, a prominent American engineer bought an expensive player-piano. It became clear after a week or two that this purchase did not correspond to any particular interest in the music played by the piano but rather to an overwhelming interest in the piano mechanism. For this gentleman, the player-piano was not a means of producing music, but a means of giving some inventor the chance of showing how skillful he was at overcoming certain difficulties in the production of music. This is an estimable attitude in a second-year high-school student. How estimable it is in one of those on whom the whole cultural future of the country depends, I leave to the reader.

Oh, snap!

More seriously though, this definitely feels like a criticism of the era in which Wiener was writing. Game theory was very fashionable, and the pseudo-mathematization of Cold War geopolitics definitely gave him pause. I don’t think Wiener would agree current railing against “wasteful” government spending on “useless” research projects, despite his obvious dislike of vanity research and his disappointment with this science of his day. It was important to him that scientists remained free from political pressures and constraints to conform to a government agenda (as described in A Fragile Power).

Norbert Wiener was a man of constant sorrow

He was hitting the haterade pretty hard:

The vacuum tube was first used to replace previously existing components of long-distance telephone circuits and wireless telegraphy. It was not long, however, before it became clear that the radio-telephone had achieved the stature of the radio-telegraph, and that broadcasting was possible. Let not the fact that this great triumph of invention has largely been given over to the soap-opera and the hillbilly singer blind one to the excellent work that was done in developing it, and to the great civilizing possibilities which have been perverted into a national medicine-show.

some slightly more recent reads

Suspended in Language (Jim Ottaviani and Leland Purvis) — a graphic novel about Niels Bohr, his life, his theories, and the birth of modern physics. This was a great read and wonderful introduction for those with a scientific bent but perhaps less physics background (me in a nutshell).

Logicomix(Apostolos Doxiadis and Christos Papadimitriou) — continuing with the intellectual comic book trend, this was a semi-fictionalized history of the foundations of mathematics from the perspective of Bertrand Russell. There’s a lot going on in the book, which tries to examine the connections between logic and madness, maps versus reality, and Russell versus Wittgenstein. I very much enjoyed the beginning of the book but it sort of rushed into the ending : I wanted more about Gödel!

Botany of Desire (Michael Pollan) — this is a lyrically written book about the relationship between people and plants. Pollan goes through 4 case studies : the apple, the tulip, marijuana, and the potato, and describes how the plants satisfy human desires and how humans have shaped the course of their evolution. The writing in this book is beautiful, but his favorite words seem to be Apollonian, Dionysian, and chthonic, which lends some of the text an almost 19th century feeling. His dissection of the issues with GMO farming and Monsanto in the potato chapter is great, but I wish it was more accessible to the average reader. Ah well, it’s a book for elites, and a very pretty book at that.

Interracial Intimacy: The Regulation of Race and Romance (Rachel F. Moran) — This was a slightly more legalistic and policy-oriented analysis of how interracial relationships were regulated by the state in the United States. Unlike Kennedy’s book, it has a fair bit more about non black-white relationships, and highlights the differences faced by different ethnic groups. Also unlike Kennedy’s book, it is not aggressively arguing an a particular agenda. Kennedy was building up an argument against race-matching in adoption, and Moran is a little more circumspect and seems (at least to my mind) to be more attuned to the dangers of being prescriptivist. It’s definitely a dry read, but I found it quite informative.

Completely ridiculous stock photography

I get the IEEE Communications and Signal Processing magazines electronically to save paper (I find they don’t make for great bus reading, so the print version is less appealing). Every month they dutifully send me an email with possibly the most ridiculous stock images. For example, here’s the one for the Signal Processing magazine:

Happy Signal Processing Dude

Oh man, I am so STOKED to get this Signal Processing Magazine! Wooo hoooo!

First off, who is this dude, and what is wrong with his life such that getting this magazine makes him so happy? Clearly he’s not an engineer since he’s wearing a suit. Maybe he works in finance? Of perhaps government, since he’s walking down some pretty “city hall”-looking stairs. Maybe it’s a courthouse, and he’s been cleared of all charges, thanks to the evidence in the signal processing magazine?

Now here’s the Communications one:

Peek inside Communications

Hey there, want to have some sitcom-like hijinks with 4G communication systems?

Again, who is this woman, and why is she creepily hiding behind the magazine, only to pop around the side, holding the pages shut just as I’m opening it? You scared me, lady! What are you trying to do, give me a heart attack? Or are you some sort of not-so-subtle ploy to lure the predominantly male engineering audience to download the magazine?

Honestly, I wish IEEE would not bother paying for the graphic design of the download image and instead use the money for something else, like defraying subscription costs for developing nations. As it stands, these emails make me take the magazine less seriously.