I’m happy to announce that in January 2014 I will be joining the Electrical and Computer Engineering Department at Rutgers, The State University of New Jersey, as an Assistant Professor.

I’ve had to do a lot of explaining about my current position and institution since moving here, especially when I go visit ECE departments. So I figured I might use the blog to give a quick rundown of the job. I’m a Research Assistant Professor at the Toyota Technological Institute at Chicago, a philanthropically endowed academic computer science institute located on the University of Chicago campus.

  • The Toyota Technological Institute at Chicago is a branch of the Toyota Technological Institute in Nagoya, Japan. Their website is a little slow to load, but the Wikipedia entry has more quick facts. TTI-Japan was founded through an endowment from the Toyota Motor Corporation in 1981 (so it’s younger than me). The Toyota Motor Corporation is not my employer, although some executives are on the board of the school.
  • I do not work for Toyota. My research has nothing to do with cars. At least not intentionally.
  • TTI-Chicago is basically a stand-alone computer science department and was started in 2003. It only has graduate students and grants its own degrees. It happens to be located on the University of Chicago campus — we rent two floors of a building which also contains the IT services. Classes at TTI are cross-listed with the University of Chicago — students at TTI take classes at UChicago and students at UChicago take classes at TTI.
  • I get an “affiliate” card for UChicago which lets me use the library and stuff. It’s great to have a library there, but since UChicago has no engineering, my access to IEEExplore is a bit limited.
  • The research at TTI-Chicago is mostly in machine learning, computer vision, speech processing, computational biology, and CS theory. This makes me a bit of an odd-one-out, but I have been doing more machine learning lately. It’s fun learning new perspectives on things and new problems.
  • The Research Assistant Professor position at TTI-Chicago is a 3-year position (some people have stayed for 4) which pays a 9 month salary (out of general institute funds) and gives a yearly budget for research expenses like travel/conferences and experimental costs (e.g. for Mechanical Turk or Amazon EC2). It’s not a “soft money” position but people are free to raise their summer salary through grants (like I did) or by taking a visiting position elsewhere for part of the year. I do not have to teach but can offer to teach classes or help teach classes
  • There are tenure-track faculty at TTI, and it’s the same tenure deal as elsewhere. Their teaching load is one quarter per year (that should make people jealous).
  • There are graduate students here, but not a whole lot of them. I can’t directly supervise graduate students but I can work with them on research projects. I’m starting to work with one student here and I’m pretty excited about our project.

Bikash Dey, Mike Langberg, Sid Jaggi, and I submitted an extended version of our (now accepted) ISIT paper on new upper bounds for binary channels with causal adversaries to the IT Transactions. The model is pretty straightforward : Alice (the encoder) transmits a message to Bob (the receiver) encoded over n uses of a binary input, binary output channel. The channel is controlled by Calvin (an adversary) who sequentially looks at each bit and can decide whether or not to flip it, up to pn total bit flips. That is, Calvin is causal : the decision to flip bit i is based on the knowledge of bits 1, 2, \ldots, i. What we show is a new upper bound on the capacity of this channel. Let \alpha(p,\bar{p}) = 1-4(p-\bar{p}). Then

C \le \min_{\bar{p} \in [0,p]} \left[ \alpha(p,\bar{p})\left(1-H\left(\frac{\bar{p}}{\alpha(p,\bar{p})}\right)\right) \right]

This is what it looks like:

New Upper Bound for Causal Adversaries

Plot of the new upper bound


So clearly causal adversaries are worse than i.i.d. noise (the 1 - H(p) bound).

To show such a bound we have to propose a new attack for the adversary. We call our attack “babble and push.” It operates in two phases. The first phase is of length \ell channel uses and the second of length n - \ell. Let \mathbf{x}(m) be the codeword for message m.

  1. (Babble) Calvin chooses a random subset \bar{p} n indices uniformly from all (\bar{p} n)-subsets of \{1, 2, \ldots, \ell\} and flips bit i for i \in \Gamma.
  2. (Push) Calvin finds all possible codewords which are consistent with what Bob has received in the first phase:

    B_{\mathbf{y}^{\ell}} = \{ u : d_H(\mathbf{y}^{\ell}, \mathbf{x}^{\ell}(u))=\bar{p}n \},

    and selects an element \hat{u} \in B_{\mathbf{y}_1} uniformly at random. For the second phase, Calvin selectively pushes the received codeword towards \mathbf{x}(\hat{u}) — if the transmitted codeword and the selected codeword match, he does nothing, and if they do not match he flips the bit with probability 1/2.

Analyzing this scheme amounts to showing that Calvin can render the channel “symmetric.” This is a common condition in arbitrarily varying channels (AVCs), a topic near and dear to my heart. Basically Bob can’t tell the difference between the real codeword and the transmitted codeword, because under Calvin’s attack, the chance that Alice chose u and Calvin chose \hat{u} is the same as the chance Alice chose \hat{u} and Calvin chose {u}. To establish this symmetry condition requires some technical excursions which are less fun to blog about, but were fun to figure out.

It’s relatively clear that this approach would extend to more general AVCs, which we could work on for the future. What is neat to me is that this shows how much value Calvin can derive by knowing the current input bit — by forcing additional uncertainty to Bob during the babble phase, Calvin can buy some time to more efficiently use his bit flipping budget in the second phase.

I am singing with the UChicago Early Music Ensemble, a somewhat relaxed group led by David Douglass and Ellen Hargis of The Newbury Consort. I started rehearsing a bit late, so I’ve been playing catch-up. This year the repertoire is all music from Spain and Spanish colonies, and today we worked on two of the harder pieces in the program : an ensalada called La Bomba, by Mateo Flecha “El Viejo”, and a jacara by Juan Gutiérrez de Padilla. Too many words!

In looking for some recordings to get a better sense of the pieces, I came across this charmingly old King’s Singers TV special (check out those sweater vests!) acting out La Bomba in what appears to be the house from Clue:

Lucky them, they get multiple takes which makes it a bit easier to manage the crazy transitions in the piece. There’s also a multitracked recording on which is pretty good:

Unfortunately we are doing it up a third from there, much to the chagrin of my passagio.

We spent a bit of time trying to get the jácara up to speed, but singing Spanish that fast is hard! When I heard how fast this version went I almost lost it:

It looks like I have my work cut out for me, especially if I want to roll my r’s like that.

Congratulations to my fellow Beast Amitha Knight on being a co-winner of the 2012 PEN New Enlgand Susan P. Bloom Children’s Book Discovery Award!

Speaking of children’s books, some people who saw The Hunger Games movie are upset that Rue is black. Unsurprising but sad.

And speaking of friends, my friend Amber is slumming it in Antarctica and is writing some fascinating blog posts from down there.

Can Ellen Do More Push-Ups Than Michelle Obama? They both seem to be able to do more pushups than me. Time to hit the gym I think.

I’ve been eating this spicy peanut noodle salad for lunch this week and boy is it delicious.

Sacra Profana, a San Diego choir with whom I have performed before, is hoping to get funding for a new CD via a kickstarter campaign. There’s less than two weeks left in the campaign and we are getting close to our goal, but if you read this blog and are feeling generous (every $5 counts), please consider supporting this group. They are doing some really innovative programming — we did Ligeti’s Lux Aeterna, a piece I have loved since high school and never thought I would get the chance to perform.

This is my last concert in San Diego, schade! It should be a good one!

In Memoriam: Marking the tenth anniversary of 9/11

W.A. Mozart : Requiem in D minor, K 626 (Levin completion)

Bach Collegium San Diego
Ruben Valenzuela, dirigent

Claire Fedoruk (Soprano)
Angela Young Smucker (Alto)
Pablo Corá (Tenor)
Mischa Bouvier (Bass)

St. James by-the-Sea Episcopal Church
San Diego, California
Friday, 16 September 2011
7:30 PM

Pt. Loma Nazarene University: Crill Hall
San Diego, California
Saturday, 17 September 2011
7:30 PM

Tickets available online.

I have accepted an offer to join the Toyota Technological Institute at Chicago this fall as a Research Assistant Professor. I’m excited by all of the opportunities there; it’s a great chance to dig deeper into some exciting research problems while learning a lot of new things from the great people they have there. It’s in Hyde Park, which is a great stepping stone for future career opportunities

I’m heading off to Mexico in less than 12 hours for a week during which I hope to disconnect : no email, web, or phone. I guess I’ll miss the majority of the post-Bin Laden news cycle. In the meantime, here are some more links because I am too lazy to post content.

Speaking of 9/11, this is simply terrible.

An interview with George Saunders, one of my favorite authors.

Blackwell’s proof of Wald’s Identity, as told by Max.

Long pepper looks fascinating and tasty!

Can Voter ID Laws Be Administered in a Race-Neutral Manner? The short answer is no. The longer answer is a 30 page paper.

Frank has blogger about our trip last weekend to The 2nd 8th Annual Grilled Cheese Invitational. My arteries may never be the same again.

There are no more typewriter factories. This makes me especially sad, as I have a 1914 Underwood No. 5 that I love (and lug).

SACRA/PROFANA (dir. Krishan Oberoi) presents…

EX/CAN/DES/CENT*
*a. [L. excandescentia .] 1. Growing hot; white or glowing with heat

Saturday, February 19 · 7:00pm – 8:30pm
St. Peter’s Church
off of 15th St., Del Mar, CA
Sunday, February 20th at 4 p.m.
Village Community Presbyterian Church
6225 Paseo Delicias, Rancho Santa Fe

San Diego’s virtuosic vocal ensemble SACRA/PROFANA returns in a
program exploring themes of light and illumination. New works by young
American composers will be highlighted, including winners of the 2010
Choral Composition Contest. Also featuring music by Poulenc, Britten
and The Smashing Pumpkins, plus György Ligeti’s enigmatic choral
masterpiece “Lux Aeterna”.

15th Street Chamber Music says:”SACRA/PROFANA features some of the
premier young voices from all around San Diego and Southern California
and has a fresh new sound with a thrilling take on the art of choral
music.”

More information at: www.sacraprofana.org.

There is a $10 suggested donation at the door. Reserve seats are
available by emailing us at:
15thstreetchambermusic@gmail.com

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