Category Archives: News

4th World Congress on Social Simulation

I’m currently attending the 4th World Congress on Social Simulation, which is being held in Taipei, Taiwan at National Chengchi University.  I gave a presentation today entitled ‘Semi-Artificial Models of Populations: Connecting Demography with Agent-Based Modelling’.  I enjoyed giving the talk, particularly the encouraging and valuable feedback I received from colleagues from Russia, Japan and America.

I’ve uploaded my slides — bear in mind they were written in somewhat of a rush!

As for Taiwan, so far it’s been fantastic.  The streets are lively and clean, public transport is fast, cheap and reliable, the food is great, and people have been very polite and helpful.  Taipei 101 was particularly impressive; the building design is striking and the views are spectacular.  I’m looking forward to seeing more sights during the rest of my week here in Taiwan!

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Persistence and Uncertainty in the Academic Career

Good article for those of us who are substantially irked by the short-sighted use of fixed-term contracts in academia:

http://arxiv.org/abs/1204.0752  (PDF download link on the right-hand side)

The important bit of the abstract:

“We introduce a model of proportional growth which reproduces these two observations, and additionally accounts for the significantly right-skewed distributions of career longevity and achievement in science. Using this theoretical model, we show that short-term contracts can amplify the effects of competition and uncertainty making careers more vulnerable to early termination, not necessarily due to lack of individual talent and persistence, but because of random negative production shocks. We show that fluctuations in scientific production are quantitatively related to a scientist’s collaboration radius and team efficiency.”

And the discussion gives a nice summary:

“One serious drawback of short-term contracts are the tedious employment searches, which displace career momentum by taking focus energy away from the laboratory, diminishing the quality of administrative performance within the institution, and limiting the individual’s time to serve the community through external outreach [3, 6]. These momentum displacements can directly transform into negative productivity shocks to scientific output. As a result, there may be increased pressure for individuals in short-term contracts to produce quantity over quality, which encourages the presentation of incomplete analysis and diminishes the incentives to perform sound science. These changing features may precipitate in a ‘tragedy of the scientific commons’….

However, this model also shows that the onset of a fluctuation-dominant (volatile) labor market can also be amplified when the labor market is governed by short-term contracts  reinforced by a short-term appraisal system. In such a system, career sustainability relies on continued recent short-term production, which can encourage rapid publication of low-quality science. In professions where there is a high level of competition for employment, bottlenecks form whereby most careers stagnate and fail to rise above an initial achievement barrier. Instead, these careers stagnate, and in a profession that shows no mercy for production lulls, these careers undergo a ‘sudden death’ because they were ‘frozen out’ by a labor market that did not provide insurance against endogenous fluctuations. Such a system is an employment ‘death trap’ whereby most careers stagnate and ‘flat-line’ at zero production. However, at the same time, a small fraction of the population overcomes the initial selection barrier and are championed as the ‘big winners’, possibly only due to random
chance.”

This makes for compelling reading, especially given that the usual justification for the use of fixed-term contracts seems to be the alleged benefits of the inevitable competition for posts — which our overlords would have us believe allows the cream to rise to the top.  What we see here is that, in contrast to the management view, short-term contracts amplify the effects of problems in research production, and those who rise to the top may have done so purely by being lucky rather than particularly skilled.  Meanwhile, the system creates a massive wastage of talent by cutting short potentially promising careers, given that research productivity can be stunted by problems in research teams (which continue to grow larger and more complex over time) or unfortunate bad luck in experiment outcomes or similar, and not necessarily by a lack of effort or skill.

Meanwhile, the focus on short-term contracts with short-term appraisals leads to an intense pressure to publish sub-par science more frequently, rather than well-considered, long-term research with more potential impact.  The loss of productivity due to worries over job insecurity and time-consuming, highly-competitive job application procedures is also not to be underestimated.

When I started my first postdoc I was advised to start looking for my next job when I still had a year left on my contract.  I did so and found, as most others do, that finding an appropriate academic position is very difficult due to the extreme specialisation of every post — if you’re unlucky and there’s not much in your area kicking off when you happen to be looking, you might end up struggling for work through no fault of your own.  Not to mention that it wasn’t uncommon for me to have to send 50+ pages of material to each potential job, causing me to waste rather a lot of time that I could’ve been using for my research.  In the end, getting your next post seems to rely much more on luck, timing, and networking than anything else.

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Submitted a paper to Demographic Research

Yesterday my colleagues Jakub Bijak, Jason Hilton, Viet Cao and I submitted another paper, this one to the journal Demographic Research.  This one is also related to Francesco Billari’s model of partnership formation, but in this case we performed a replication and extension of the original model with a substantial focus on in-depth investigation of the mechanisms underlying the resulting population dynamics.

This kind of paper is fairly unusual in a demography journal, in that agent-based modelling techniques remain largely outside of standard methodology in that field.  Our hope is that we can build on Billari’s attempts to bring new methodologies into demography, and perhaps encourage some enthusiasm for the approach.

Demographic Research is free and open access, just like JASSS, so if our paper gets accepted you’ll soon see the link on this very page.

 

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Submitted a paper to JASSS

On Friday, I submitted a paper as first author to the Journal of Artificial Societies and Social Simulation, together with my colleagues Jakub Bijak, Viet Cao, Jason Hilton and Jason Noble.

The paper describes an agent-based model applied to the study of partnership formation.  We base the model on a previous one by Francesco Billari called ‘The Wedding Ring’, and extend the model into two spatial dimensions while including substantive empirical data to drive mortality and fertility rates for agents in the model.  We conclude by utilising novel methods of uncertainty quantification (Gaussian emulators) to investigate the impact of some of the key parameters on model output.

We’re excited about this one!  A related paper is headed to Demographic Research within the next few days, so it’s been a productive summer.  Both journals are fully open-access, so if we’re fortunate enough to get both of them accepted links will be posted here on the Publications page.

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Joined academia.edu

My current mission of expanding my academic web presence continues, now that I’ve got a profile on academia.edu.

I’ll have to add my papers to my profile manually, since the import tool doesn’t seem to want to find my papers on my Publications page here, but that will be done soon.

You know, this makes me think how nice it would be to have a page where you can collaborate live, publish and review papers, and follow the work of your colleagues, all in one place.  Perhaps, someday, someone will set up a site like this….

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More music

Just for kicks — an hour of Frenchcore (hardcore techno by French people).  I particularly enjoy the sample that starts off this set; I’m not sure where the artist found it, but it’s certainly… unique.

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Added a music page

I’ve just added a new page to the site — this just links to my SoundCloud account for now.  I’ve got a couple of my DJ mixes available there for free, with more to come!  Both of the mixes on SoundCloud at the moment are drum & bass, but I’ll be updating soon with some hardcore, techno and hardstyle mixes as well.

What I may do is simply migrate my music to MediaFire or some other free file hosting service, as both SoundCloud and WordPress charge significant fees for audio storage.  I’ll update the blog once I’ve found a good home for everything.

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Basic minds without content

I just heard about an interesting new book on the horizon from Daniel Hutto and Erik Myin called Radicalizing Enactivism: Basic Minds Without Content.  The preface is downloadable, and the authors got my attention pretty early on with this paragraph:

“This raises the worry that the whole enactive and embodied turn in cognitive science is backed by little or nothing more an unreasoned attachment to certain attractive, but ultimately empty, pictures and slogans. For this reason, Prinz (2009) is right to proclaim that – at least in one sense – enactive and embodied approaches may be easier to “sell than to prove” (p. 419).

We aim to supply the philosophical clarifications and strong support that has been sorely missing.”

The criticisms mentioned in the preface line up fairly precisely with my own, so I’m quite interested to see what they come up with to address these issues.  I can also admit to a certain morbid curiousity about how enactivism can be pushed even farther.

I do find myself wondering where the endpoint will be, however.  So far we’ve dismissed qualia, now apparently mental content of any sort is gone, so what’s next?  Will we slide all the way back to behaviourism, then Chomsky will write another devastating critique of it like back in 1967, and then we’ll go round the whole cycle again?

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Report from UCM 2012, Sheffield

Jakub Bijak, Jason Hilton and myself attended the Uncertainty in Computer Models conference in Sheffield earlier this month (http://www.mucm.ac.uk/UCM2012.html).

Our poster was well-received, and attracted a good number of interested colleagues. Among those coming to speak to us were some colleagues from the National Oceanography Centre, also from Southampton, who had a number of posters and presentations at the conference, mostly to do with wind and wave models. Peter Challenor has been a major part of the MUCM project which spawned the conference, and he gave the initial presentation here in Southampton which inspired us to use the project’s tools on our agent-based model. We also spoke with Stephen Chick from INSEAD, several folks from Sheffield and UCL, and some gentlemen from industry including Ball Aerospace and Pratt & Whitney, and also a fellow from the US Air Force (he had some remarkable pictures of lasers mounted on fighter jets).

The attendees were very mixed, and presented work from a huge variety of fields. The commonality was a focus on quantifying uncertainty in models, whether those models were of climate, mechanical components, ocean currents, or in our case populations. Some of the talks were very intensely statistical, and demonstrated that there is a lot of cutting-edge work being done in this area — work that involves techniques we have yet to learn. But through attending the talks and speaking with other presenters, we now have a number of opportunities to learn more, and potential links for collaborative efforts.

What was most striking was to see the huge impact of this work on modeling techniques across this huge variety of fields. We saw how quantifying uncertainty and altering modelling techniques in response produced huge gains in efficiency for industrial applications, and how Gaussian emulators can allow for innovative modelling methods that save incredible amounts of computing time. We also heard some conceptual arguments regarding the effects of uncertainty in climate models; in particular, the talk on this topic by Jonty Rougier (delivered without slides, with him standing in front of the room barefoot) was extremely thought-provoking and one of the best talks of the conference. His talk was based on a book chapter which was recently completed for an upcoming volume entitled Conceptual Issues in Climate Modeling (U Chicago Press), and a draft of the chapter is available here:

http://www.maths.bris.ac.uk/~MAZJCR/climPolUnc.pdf

While the talk mainly referred to climate models, the content was quite applicable to any discipline using highly complex computational models, so I recommend giving it a look.

All told, the conference was intense and challenging. We came away with some useful new contacts and new ideas, and with the distinct sense that our modelling efforts could stand to gain substantial legitimacy and novelty by applying these techniques of quantifying uncertainty. The response to our early-stage efforts was very encouraging, and we think that continuing with this will produce great dividends in our efforts to make our models both more powerful and more useful.

Paper for WCSS 2012

I’m pleased to say I’ll be presenting a paper at the 4th World Congress on Social Simulation, to be held in Taipei, Taiwan from 4-7 September 2012.  My paper is a multidisciplinary simulation effort incorporating substantial demographic expertise from my colleagues Jakub Bijak and Jason Hilton.

View/print the paper from my Google Docs repository here:  Semi-Artificial Models of Population: Connecting Demography with Agent-Based Modelling

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