Neural Computation discussion group

Today I'm just going to run a quick advertisement for a new series we're starting in our discussion group on"Neural Computation". It's on Fridays @ 2 pm at CSIRO Marsfield (north-west Sydney), but is open to anyone from outside who is interested.

More details, including the schedule of talks, is available at http://www.prokopenko.net/entropy.html

As it happens, stumbling upon a link for these talks and subsequently coming along to them is how I met Mikhail which led to me starting my PhD. So if you're interested in the area, do come along as you never know where it might lead you!

Funny stunt

Here I was thinking that I was procrastinating about writing up my PhD. Not as much as these guys:
http://dataphiles.blogspot.com/2009/09/machine-learning-protest-at-g20.html
One of the funniest things I've seen for a while ...

Apology to Turing

Not mine, the British government's.

Better late than never.

Information, computation and complex systems workshop

A quick post to advertise the Information, Computation and Complex Systems satellite meeting, which is part of ECCS 09.

From the workshop page:

This workshop will bring together mathematicians and scientists to discuss methods and applications of information theory to complex systems. This includes the perspective of complex systems as computers.
The question of good measures of complexity alone is vital for complex systems research. Many proposals have been made, quite a few based on information theory. The workshop addresses the following topics:

1. Mathematics of information theoretic tools for complex systems
2. Information theory applied to complex systems
3. Complex systems as information processors

The workshop will provide a forum for discussing the various existing information-theoretic and computation-theoretic tools, and their use in complex systems.
The focus will be on the mathematics of information and computation theory applied to complex systems. We encourage both theorists and experimentalists to attend, with either an information theoretic approach or a need for an information theoretic approach.

I think this will be a really interesting workshop, as it directly relates to the focus of my PhD. The invited presentations should be quite good. I'm hoping to get the opportunity to present my own approach of the local information dynamics of distributed computation in complex systems, and hope to meet some people there with the need for this kind of approach.

Submissions are apparently open until Mon 24/8/09, hope to see you there.

Update 1/9/09 - my submission "Coherent local information dynamics in complex computation" was accepted, so I'm now looking forward to presenting at ICCS. The schedule has been posted.

The Ashes 2009

Tonight (Australian time) marks the start of the 2009 Ashes series in the UK. For the uninitiated, The Ashes is the "trophy" for Australia vs England cricket series. These series occur roughly every two years, with a series hosted by each country each four years. For an Australian player or fan, an Ashes series in England is as good as it gets.

To say I am looking forward to the coverage is an understatement. I would really love to get to England for the series one day. I'll be nearby in Germany during the last game of the series this year, but unfortunately all of the tickets are sold out.

As I'm sitting here watching the first few overs, I've been thinking about how I can almost mark progress in my life by what I was doing while watching the Ashes from England every four years. In 1989 I was just finishing primary school. I hadn't been interested in or playing cricket for long, but it sure took up a lot of my thinking. In 1993 I was mid-way through high school, and by this point was taking my studies fairly seriously as I had realised what I could achieve academically. I remember watching the games up late after coming home some of the first times I was allowed to go out with my friends at night. By 1997 I was a couple of years into uni, really enjoying engineering. I was also going out with my wife (then girlfriend) by then and my enduring memory of that series is watching it at her place after everyone else was asleep. 2001 was a big year for growing up: first full-time job, moving out with my girlfriend and thinking about getting married. It was nice watching that series late at night in a place I could call my own. Much better was 2005, when I could watch it in an apartment I owned rather than rented. By this time, we were married, and I had established myself at work though I was thinking a lot about how to go about doing a PhD as I was watching the games. This time, I'm sitting in our own house, am writing up my thesis, and my wife has begun her PhD studies. This time around I'll be occupied by what I/we are going to do next year once I'm finished. I wonder where I will be in four years time?

The information dynamics of cascading failures in energy networks

Disclaimer: shameless self-promotion follows.

So our submission:

Joseph T. Lizier, Mikhail Prokopenko, David J. Cornforth, "The information dynamics of cascading failures in energy networks"

to ECCS 2009 was accepted, and I'll be presenting it in the Policy, Planning and Infrastructure track currently on the Friday morning of the conference.

The abstract is as follows:

Small failures in electrical energy networks can lead to cascading failures that cause large and sustained power blackouts. These can disrupt important services and cost millions of dollars. It is important to understand these events so that they may be avoided. We use an existing model for cascading failures to study the information dynamics in these events, where the network is collectively computing a new stable distribution of flows. In particular, information transfer and storage across the network are shown to exhibit sensitivity to reduced network capacity earlier than network efficiency does, and so could be a useful indicator of critical loading. We also show that the local information dynamics at each node reveals interesting relationships between local topological features and computational traits. Finally, we demonstrate a peak in local information transfer in time coinciding with the height of the cascade's spread.

In a nutshell, this paper describes an application of our framework for the information dynamics of distributed computation to the phenomena of cascading failures on networks. The focus is on energy networks, though the results are applicable to other types of networks, e.g. transport.

Information dynamics may at first not seem applicably to cascading failures, but there are a few good reasons for the application here. First, cascading failures are akin to damage spreading phenomena, and both are often cited as mechanisms of information transfer in networks: it is useful to explore this quantitatively. Further, when a cascading failure occurs, the network is actually computing a new stable state (or attractor), so quantifying the information dynamics is a direct study of this computation. To underline all that, I really like this quote from Melanie Mitchell's new book:

The phenomena of cascading failures emphasizes the need to understand information spreading and how it is affected by network structure.

Primarily, the results show that we get maximisations of information transfer and storage in the network near the critical phase, aligning with our findings in Random Boolean Networks (RBNs) in a paper at ALifeXI last year. We also find some interesting relationships between topological properties of the individual nodes and their own local information dynamics.

From here, I'll be combining this work with that on RBNs in my PhD thesis, and probably seeking to make a journal submission from their combination.

Second International Workshop on Guided Self-Organisation (GSO-2009)

Just a quick post to advertise The Second International Workshop on Guided Self-Organisation (GSO-2009) which I'm planning on attending in August.

A few pertinent clips from the workshop's website:

"... by its very nature, self-organization more often than not has its own way. To be useful in practice, methods of guiding self-organization towards prespecified goals have to be developed. Adding and controlling constraints provides one possibility to this end.
Many properties of self-organisation can be characterised formally (e.g., information-theoretically). However, the lack of agreement of what is meant by complexity, constraints, etc, as well as a common methodology across multiple scales leaves any definition of self-organisation somehow vague, indicating a clear gap. Filling this gap and identifying common principles of guidance are the main themes of GSO-2009. The workshop will put particular emphasis on principles based on information flows through the perception-action loop of embodied systems."

GSO-2008 was a really interesting week, so am hoping for the same level of inspiration this time round.

Registration is open, hope to see you there.