# The NSF and the sequester

My department chair sent out a recent notice from the NSF about the impact of the sequestration order on the NSF awards.

At NSF, the major impact of sequestration will be seen in reductions to the number of new research grants and cooperative agreements awarded in FY 2013. We anticipate that the total number of new research grants will be reduced by approximately 1,000.

In FY2011 the NSF funded 11,185 proposals, so that’s an 8.94% reduction. Yikes.

# Bellairs Workshop 2013

I just wanted to write a few words about the workshop at the Bellairs Research Institute. I just returned from sunny Barbados to frigid Chicago, so writing this will help me remember the sunshine and sand:

The beach at Bathsheba on the east coast of Barbados

Mike Rabbat put on a great program this year, and there were lots of talks on a range of topics in machine learning, signal processing, and optimization. The format of the workshop was to have talks with lots of room for questions and discussion. Talks were given out on the balcony where we were staying, and we had to end at about 2:30 because the sunshine would creep into our conference area, baking those of us sitting too far west.

# ITA 2013 : part the third

I think this is the end of my ITA blogging! But there were some issues that came up during the conference that may be of interest to some of the readers of this blog (although from anecdotal reports, there are many people who read but never comment, so I’m not sure what to do to encourage more discussions).

# Postdoc position at EURECOM

(via David Tse)

EURECOM’s Communications Theory Group is looking for a highly qualified postdoctoral researcher in the areas of communications theory, cooperative wireless networks, and cloud-aided radio access. The position is open NOW and is to be filled preferably before summer 2013. The location is European Tech-Park Sophia Antipolis, France. Details follow below or can be found underhttp://www.eurecom.fr/cm/gesbert/recruiting or in the text below. If you are interested please contact immediately Prof. David Gesbert (gesbert@eurecom.fr) with CV+motivation.

# Results on petition for Increasing Public Access to the Results of Scientific Research

I signed a petition to the White House a while ago about increasing public access to government-funded research — if a petition gets 100,000 signatures then they White House will draft a response. Some of the petitions are silly, but generate amusing responses, c.f. This Isn’t the Petition Response You’re Looking For on government construction of a Death Star. The old threshold was 60K, which the petition I signed passed. On Friday I got the official response from John Holdren, the Director of the White House Office of Science and Technology Policy. The salient bit is this one:

# Bellairs Workshop

I’m at the Bellairs Research Institute for a workshop this week and I’ll blog a bit later about some of the interesting talks here. We give the talks on the balcony of one of the buildings, projected on the wall. Fortunately, we are facing west, which means talks have to end at around 2:30 before people start baking to death. After all that superheated research the only thing to do, really, is cool off in the ocean next door…

The beach at Belairs

# ITA 2013 : post the second

Again a caveat — these are the talks in which I took reasonable enough notes to write anything coherent.

Green Communication: From Maxwell’s Demon to “Informational Friction”
Pulkit Grover
Pulkit talked about trying to tie a physical interpretation the energy used in communication during computation. Physicists might argue that reversible computation costs nothing, but this ignores friction and noise. Pulkit discussed a simple network model to account for “informational friction” that penalizes the bit-distance product in communicating on a chip. See also Pulkit’s short video on the topic.

Hajar Mahdavi-Doost, Roy Yates
Roy talked about a model in which receivers have to harvest the energy they need for sampling/buffering/decoding the transmissions. These three tasks cost different amounts, and in particular, the rate at which the receiver samples the output dictates the other parameters. The goal is to choose a rate which helps meet the decoder energy requirements. Because the receiver has to harvest the energy it needs, it has to design a policy to switch between the three operations while harvesting the (time-varying) energy available to it.

Multiple Access and Two-way Channels with Energy Harvesting and Bidirectional Energy Cooperation
Kaya Tutuncuoglu Aylin Yener
Unlike the previous talk, this was about encoders which have to transmit energy to the receivers — there’s a tradeoff between transmitting data and energy, and in the MAC and TWC there is yet another dimension in how the two users can cooperate. For eample, they can cooperate in energy transmission but not data cooperation. There were a lot of results in here, but there was also a discussion of policies for the users. In particular a “procrastination” strategy turns out to work well (rejoice!).

An equivalence between network coding and index coding
Michelle Effros, Salim El Rouayheb, Michael Langberg
The title says it all! For every network coding problem (multiple unicast, multicast, whatever), there exists a corresponding index coding problem (constructed via a reduction) such that a solution to the latter can be easily translated to a solution for the former. This equivalence holds for all network coding problems, not just linear ones.

Crowd-sourcing epidemic detection
Constantine Caramanis, Chris Milling, Shie Mannor, Sanjay Shakkottai
Suppose we have a graph and we can see some nodes are infected. This paper was on trying to distinguish between whether the infected nodes started from a single point infection spread via an SI model, or just from a random pattern of infection. They provide two algorithms for doing this and then address how to deal with false positives using ideas from robust statistics.

# A village of indomitable researchers

The year is 50 BC. Gaul is entirely occupied by the Romans. Well, not entirely… One small laboratory of indomitable Gauls still holds out against the invaders…

• Stationaryergodix
• Binarysymmetrix
• Channelmatrix
• Stochastix
• Cyclicprefix
• Nonlineardynamix
• Pseudometrix
• Empiricalrix
• Kerneltrix
• Orderstatistix
• Bayesianonparametrix
• Bigdatanalytix

# ITA Workshop 2013 : post the first

I promised some ITA blogging, so here it is. Maybe Alex will blog a bit too. These notes will by necessity be cursory, but I hope some people will find some of these papers interesting enough to follow up on them.

A Reverse Pinsker Inequality
Daniel Berend, Peter Harremoës , Aryeh Kontorovich
Aryeh gave this talk on what we can say about bounds in the reverse direction of Pinsker’s inequality. Of course, in general you can’t say much, but what they do is show an expansion of the KL divergence in terms of the total variation distance in terms of the balance coefficient of the distribution $\beta = \inf \{ P(A) : P(A) \ge 1/2 \}$.

Unfolding the entropy power inequality
Mokshay gave a talk on the entropy power inequality. Given vector random variables $X_1$ and $X_2$ is there a term we know that $h(X_1 + X_2) \ge h(Z_1 + Z_2)$ where $Z_1$ and $Z_2$ are isotropic Gaussian vectors with the same differential entropy as $X_1$ and $X_2$. The question in this paper is this : can we insert a term between these two in the inequality? The answer is yes! They define a spherical rearrangement of the densities of $X_1$ and $X_2$ into variables $X_1^{\ast}$ and $X_2^{\ast}$ with spherically symmetric decreasing densities and show that the differential entropy of their sum lies between the two terms in the regular EPI.

Improved lower bounds on the total variation distance and relative entropy for the Poisson approximation
Igal Sason
The previous lower bounds mentioned in the title were based on the Chen-Stein method, and they can be strengthened by sharpening the analysis in the Chen-Stein method.

Fundamental limits of caching
This talk was on tradeoffs in caching. If there are $N$ files, $K$ users and a size $M$ cache at each user, how should they cache files so as to best allow a broadcaster to share the bandwidth to them? More simply, suppose there are three people who may want to watch one of three different TV shows, and they can buffer the content of one TV show. Since a priori you don’t know which show they want to watch, the idea might be to buffer/cache the first 3rd of each show at each user. They show that this is highly suboptimal. Because the content provider can XOR parts of the content to each user, the caching strategy should not be the same at each user, and the real benefit is the global cache size.

Simple outer bounds for multiterminal source coding
This was a very cute result on using the HGR maximal correlation to get outer bounds for multiterminal source coding without first deriving a single letterization of the outer bound. The main ideas are to use two properties of the HGR correlation : it tensorizes (to get the multiletter part) and the strong DPI from Elza Erkip and Tom Cover’s paper (referenced above).

# How do you attend conferences?

As I’ve gotten farther along in this whole research career, I’ve found it more and more difficult to figure out the optimal way to balance the different things one does at a conference :

• Going to talks. This is ostensibly the point of the conference. It’s impossible to read all of the papers that are out there and a talk is a fast way to get the gist of a bunch of papers or learn about a new problem in less time than it takes to really read and digest the paper. We’re social creatures so it’s more natural to get information this way.
• Meeting collaborators to talk about research problems. I have lots of collaborators who are outside TTI and a conference is a good chance to catch up with them face-to-face, actually sit down and hammer out some details of a problem, or work on a new problem with a (potential) new collaborator. Time sitting over a notepad is time not spent in talks, though.
• Professional networking. I’m on the job market now, and it’s important to at least chat casually with people about your research, what you think is exciting your future plans, and the like. This is sometimes the “real” point of conferences.
• Social networking. Sometimes conferences are the only times I get to see my friends from grad school, and in a sense your professional peers are the only people who “get” your crazy obsession with esoteric problem $P$ and like to get a beer with you.

So the question for the readership : how do you decide the right balance for yourself? Do you go in with a plan to see at least N talks or a certain set $S$ of talks, or are you open to just huddling in the corner with a notepad?

I wrote this post in an attempt to procrastinate about ITA blogging, which I will get to in a bit. I went to far fewer talks than I expected to this year, but I’ll write about ’em later.