It’s that conference season again!

September 17, 2014

This month is just raining interesting conferences again! If you’re into the kind of research I like that is: social simulation, The Connected Past, and Historical Networks Research … Ooooooh Yeeeeaaah! :)

Two weeks ago I was in Barcelona for the Social Simulation Conference and the Simulating the Past satellite conference. Reports of this event on my blog did not get beyond part 1. That’s just because Barcelona is so much fun and it would be a shame to sit in a hotel room writing blog posts any longer than I already did. The conference was great overall. There was a surprising number of talks presenting a project outline rather than results. Although conferences are good places to recruit people on such projects, these talks are not always as engaging as others.

Ulrik Brandes giving a keynote presentation at TCP London

Ulrik Brandes giving a keynote presentation at TCP London

Last week I co-organised The Connected Past with Tim Evans and Ray Rivers at Imperial College London, and the rest of the Connected Past team. It strikes me as a wonderful thing how every time we organise an event we attract a truly multi-disciplinary, young, and curious audience. Interestingly there is also always a slight majority of female scholars at The Connected Past events, which is very welcome given that in academia often the opposite is true. Our audience is always a particularly studious bunch. Humanities scholars looking to learn more about what that network thing is all about, and scholars from the hard sciences who want to know if they can jump on a research topic/problem/dataset that is slightly more sexy than gravity. The keynote talks by Alan Wilson, Ulrik Brandes and Joaquim Fort were brilliant! Each drew from their personal experiences of applying a different computation modelling approach to archaeological research: agent-based modelling, network modelling, and statistical modelling. In particular, I can recommend Brandes’co-authored paper entitled ‘what is network science?’, which is definitely required reading for anyone following this blog. I am sure this is not gonna be the last Connected Past event. In fact, I’ll be able to announce some cool TCP news very soon I hope.

This week it’s time for Historical Networks Research, an initiative that already received loads of blogspace here. No need to break the trend: expect reports from the keynotes and talks as the conference progresses over the coming days. I am particularly looking forward to the keynote by Claire Lemercier, who organised a fantastic TCP in Paris in April. Claire is a real pioneer in applying network science in history, and her review article on the subject is a must-read for any historians interested in networks. Stay tuned for more on Historical Networks Research soon!


Thoughts from Connected Pasts 2014 workshop and meeting

September 10, 2014

tombrughmans:

Ruth Fillery-Travis wrote a critical positive review of The Connected Past meeting we held Monday-Tuesday at Imperial College London. Although she argues the conference succeeded in fulfilling the promises it made in the advertisements (multi-disciplinary and awesome), Ruth raises an important issue with the use of network science techniques in archaeology. In particular, with how we use network data as a representation of the past phenomena we are interested in understanding. This is a key issue and one that archaeological network analysts commonly struggle with. But I want to emphasise such decisions are motivated by archaeological data critique and theories, they are not inherent in any way to network data as a way of representation or to network analysis techniques. It’s still early days for archaeological network science, we need more creative and experimental archaeological examples, we need more discussion such as that sparked by Ruth’s review…. But it’s gonna be worth it! :)
Thanks Ruth for actively participating at the meeting and after, stay in touch with the community!!!!

Originally posted on Ruth Fillery-Travis:

This week I spent Monday and Tuesday at the Connected Pasts workshop and meeting in London, learning about network and complexity science and its application to archaeology and the past. The two days consisted of a three hour workshop introducing and exploring one of a number software packages which can be used to analyse networks on Monday morning, followed by talks and key note speeches on Monday afternoon and through Tuesday (full program and abstracts here). The conference was held at Imperial College London, and organised locally by Tim Evans of Imperial, with Tom Brughmans of Konstanz from the wider advisory committee.

The conference was billed as multidisciplinary (within the scope of the past), and largely lived up to that; I chatted to computer scientists, geographers, statisticians, classicists and lots of physicists and archaeologists. It also attracted an international group of speakers and attendees, largely from Central…

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Geeky fun in Barcelona, part 1 #ssc14

September 4, 2014

This week I am in beautiful Barcelona for the Social Simulation conference. Not that I can really attest to this city’s beauty – I have never been here before and spent the first two days here almost exclusively in my hotel on campus preparing my paper. This will be a very recognisable experience for frequent conference goers. So Barcelona tourist tips will have to wait until blog posts at the end of the week.

I left my hotel room for two conference events only until now (Wednesday morning): the wine reception and the first keynote. The reception was actually a proper wine tasting, including long speeches about whatever happens in your nose as you taste each wine. It was of course not very surprising that the speaker struggled to keep the attention of the people he just served his produce to, who were struggling not to drown the drink straight away. But it was worth it, the wine was amazing. We were given four wines from a local wine producer, I can definitely recommend having a look at their products. The wine farmer is also experimenting with an archaeologically inspired wine, called Amphora. The clays on his land were used to create large ceramic containers (amphorae) which replace the oak barrels in which the wine matures. Apparently, the result is that the oak barrel taste which sometimes masks fruity and terroir flavours is reduced, and makes place for the amphora flavour (although he struggled to describe what an amphora tastes like since it’s a recent experiment and admittedly I asked a weird question). 

Today I attended the second keynote of the conference, Cesareo Hernandez talking about artificial economics. He argues ABM methods are necessary in economics, largely because his definition of economics demands it. Economics is a social science, according to Hernadez economics inherits complexity from the social part and it demands experimentation because it is a science. This is now generally accepted and experimental economics is part of mainstream economics, although this did not happen without a fight. Economic models now need to incorporate instability, change, and heterogeneous agents. Artificial economics tries to do just that, through computational modelling. These models should also not be created merely for their mathematical beauty but need to be socially relevant. This is something I very much agree with, if only because I understand social relevance far better than maths :) Hernandez argues three key elements should be included in all models: Agents, environments, and institutions. By varying the implementation of these elements, different artificial economies emerge.

Stay tuned for more!

IMG_0439.JPG


Bursaries available The Connected Past London

August 26, 2014

TCP (2013_05_12 19_17_14 UTC)Just a few more weeks until the next Connected Past conference! The programme is finished and again covers a good range of topics presented by scholars from different disciplines, all discussing the overlap between archaeological challenges and complexity and network science. Registration is still open so don’t hesitate to register soon. We also encourage UK-based researchers to apply for our bursaries to attend The Connected Past.

What? The Connected Past: archaeological challenges and complexity

When? 8-9 September 2014

Where? Imperial College London

Registration? https://www.eventbrite.co.uk/e/the-connected-past-london-2014-tickets-12300893303

More info? http://connectedpast.soton.ac.uk/london-2014/


KEEP THE REVOLUTION GOING! CAA 2015 call for sessions

August 12, 2014

caa2015The CAA is my favourite community of archaeologists, and I am super proud to be the CAA international secretary since April 2014. Next year’s meeting will be in Siena, Italy. And apparently we are a community of revolutionaries! This year’s theme is “KEEP THE REVOLUTION GOING”, and I couldn’t agree more. Computational techniques have revolutionised academia, and the CAA has played a pioneering role in this computational revolution for archaeology since 1973. But there is more work to be done. Computational and quantitative work in archaeology should not be a minority pursuit, they should not be considered simplistic or reductionist, all archaeologists use these techniques to some extent. The CAA community will continue to take a leading role in teaching archaeologists good practice in these techniques. So, KEEP THE REVOLUTION GOING, submit your session proposal to CAA 2015.

Where? University of Siena
When? March 30, 2015 – April 2, 2015
Submission deadline? 30 September 2014
Submission URL
More info

The 43rd Computer Applications and Quantitative Methods in Archaeology “KEEP THE REVOLUTION GOING” Conference (CAA 2015 SIENA) will explore a multitude of topics to showcase ground-breaking technologies and best practice from various archaeological and computer sciences disciplines, with a large diversity of case studies from all over the world. Some of these topics are specific to the Italian scientific community, which played since the early stage of computer applicationa central role, participating to the debate and development in particular of GIS, databases, semantic, remote sensing, 3D data collection, modeling, visualization, etc.

The conference will be held in Italy at the University of Siena in collaboration with the National Research Council, from March 30th to April 3rd 2015.

The conference usually brings together hundreds of participants coming from all over the world involving delegates in parallel sessions, workshops, tutorials and roundtables. For general information please email: info@caa2015.org


Registration open The Connected Past @ Imperial College London

July 23, 2014

TCP (2013_05_12 19_17_14 UTC)The programme has been finalised and it’s looking like it will be a great event. Time to plan your trip to London and register for The Connected Past conference and workshop at Imperial College London, 8-9 September 2014!

Register here for this event.

Outline

The Connected Past: archaeological challenges and complexity is a one and a half day multi-disciplinary meeting to explore how concepts and techniques from network- and complexity science can be used to study archaeological data. These challenges include the use of material data as proxy evidence for past human behaviour, questions about long-term processes of social change, and the fragmentary nature of archaeological data. We aim to bring together physical scientists and archaeologists in order to highlight the challenges posed by archaeological data and research questions, and explore collaborative ways of tackling them using perspectives drawn from network and complexity science.

The workshop is funded in part by an EPSRC NetworkPlus grant addressing one of Physics Grand Challenges: Emergence and Physics Far From Equilibrium so this meeting will explore ways that archaeological problems can be tackled from such a viewpoint. There is likely to be a small registration fee to cover local costs but some of the funding can and will be used to support travel by some UK based researchers.

The meeting will take place on the afternoon of Monday 8th September and all day Tuesday 9th September at Imperial College London. A hands-on introductory workshop is planned for the morning of Monday 8th September.

Keynote talks. The meeting will feature keynote talks by Alan Wilson, University College London, and Ulrik Brandes, University Konstanz (a further additional keynote will be announced soon). Shorter talks will be given by other invited speakers and from researchers submitting abstracts. Finally, at a later date we will issue a call for some quick fire (five minute) talks to allow researchers at all stages of their career to participate.

Further Information. Full details are available on the web site at
http://www.complexity.org.uk/events/conpastlondon2014/

On Twitter follow the hashtag #tcp2014

Location
Huxley 139 Lecture Theatre
More details on how to get to the meeting can be found here.

Organisers: Tim Evans (chair), Ray Rivers, Tom Brughmans, Anna Collar, Fiona Coward.
Advisory Committee: The Connected Past committee

Programme

To be announced very soon.

Registration

The registration is £40 for those with financial support or waged, £20 for students and others with limited or no financial support. This will help us cover the local expenses for your attendance, other costs (such as keynote speakers) will be supported by the EPSRC networkplus grant. Registration provides lunch on the Tuesday, coffee/tea breaks plus the informal social event on the Monday evening. Except for speakers, please REGISTER HERE for TCP2014. Speakers should register using the link provided in a forthcoming email. If you have any questions about registration, please get in touch. Also note there are a few travel bursaries, see below.

Travel Bursaries

Some support is available to cover travel and other costs of UK based researchers attending the meeting. If you wish to be considered for such support, please send a request explaining why you should be considered for a bursary to the same address as for papers with the subject “Bursary application [your name]” to connectedpast2014@imperial.ac.uk. Bursaries will be given out from mid June onwards while funds remain.


The networks they are a-changin': introducing ERGM for visibility networks

July 17, 2014

legosIn my madness series of posts published a few months ago I mentioned I was looking for a method to study processes of emerging intervisibilty patterns. I can finally reveal this fancy new approach to you :) Here it is: introducing exponential random graph modelling (ERGM) for visibility networks. In previous posts I showed that when archaeologists formulate assumptions about how lines of sight affected past human behaviour, these assumptions imply a sequence of events rather than a static state. Therefore, a method is needed that allows one to test these assumed processes. Just analysing the structure of static visibility networks is not enough, we need a method that can tackle changing networks. ERGM does the trick! I just published a paper in Journal of Archaeological Science with Simon Keay and Graeme Earl that sets out the archaeological use of the method in detail. You can download the full paper on ScienceDirect, my Academia page or via my bibliography page. But in this blog post I prefer to explain the method with LEGOs :)

 

JAS

Social network analysts often use an archaeological analogy to explain the concept of an ERGM (e.g., Lusher and Robins 2013, p. 18). Past material remains are like static snapshots of dynamic processes in the past. Archaeologists explore the structure of these material residues to understand past dynamic processes. Such snapshots made up of archaeological traces are like static fragmentary cross-sections of a social process taken at a given moment. If one were to observe multiple cross-sections in sequence, changes in the structure of these fragmentary snapshots would become clear. This is exactly what an ERGM aims to do: to explore hypothetical processes that could give rise to observed network structure through the dynamic emergence of small network fragments or subnetworks (called configurations). These configurations can be considered the building blocks of networks; indeed, LEGO blocks offer a good analogy for explaining ERGMs. To give an example, a network’s topology can be compared to a LEGO castle boxed set, where a list of particular building blocks can be used to re-assemble a castle. But a LEGO castle boxed set does not assemble itself through a random process. Instead, a step by step guide needs to be followed, detailing how each block should be placed on top of the other in what order. By doing this we make certain assumptions about building blocks and their relationship to each other. We assume that in order to achieve structural integrity in our LEGO castle, a certain configuration of blocks needs to appear, and in order to make it look like a castle other configurations will preferentially appear creating ramparts, turrets, etc. ERGMs are similar: they are models that represent our assumptions of how certain network configurations affect each other, of how the presence of some ties will bring about the creation or the demise of others. This is where the real strength of ERGMs lies: the formulation and testing of assumptions about what a connection between a pair of nodes means and how it affects the evolution of the network, explicitly addressing the dynamic nature of our archaeological assumptions.

More formally, exponential random graph models are a family of statistical models originally developed for social networks (Anderson et al. 1999; Wasserman and Pattison 1996) that aim to scrutinize the dependence assumptions underpinning hypotheses of network formation by comparing the frequency of particular configurations in observed networks with their frequency in stochastic models.

The figure below is a simplified representation of the creation process of an ERGM. (1a) an empirically observed network is considered; (1b) in a simulation we assume that every arc between every pair of nodes can be either present or absent; (2) dependence assumptions are formulated about how ties emerge relative to each other (e.g. the importance of inter-visibility for communication); (3) configurations or network building blocks are selected that best represent the dependence assumptions (e.g. reciprocity and 2-path); (4) different types of models are created (e.g. a model without dependence assumptions (Bernoulli random graph model) and one with the previously selected configurations) and the frequency of all configurations in the graphs simulated by these models is determined; (5) the number of configurations in the graphs simulated by the models are compared with those in the observed network and interpreted.

JAS_Brughmans-etal_fig4

My madness series of posts and the recently published paper introduce a case study that illustrates this method. Iron Age sites in southern Spain are often located on hilltops, terraces or at the edges of plateaux, and at some of these sites there is evidence of defensive architecture. These combinations of features may indicate that settlement locations were purposefully selected for their defendable nature and the ability to visually control the surrounding landscape, or even for their inter-visibility with other urban settlements. Yet to state that these patterns might have been intentionally created, implies a sequential creation of lines of sight aimed at allowing for inter-visibility and visual control. An ERGM was created that simulates these hypotheses. The results suggest that the intentional establishment of a signalling network is unlikely, but that the purposeful creation of visually controlling settlements is better supported.

A more elaborate archaeological discussion of this case study will be published very soon in Journal of Archaeological Method and Theory, so stay tuned :) Don’t hesitate to try out ERGMs for your own hypotheses, and get in touch if you are interested in this. I am really curious to see other archaeological applications of this method.

References mentioned:

Anderson, C. J., Wasserman, S., & Crouch, B. (1999). A p* primer: logit models for social networks. Social Networks, 21(1), 37–66. doi:10.1016/S0378-8733(98)00012-4

Lusher, D., Koskinen, J., & Robins, G. (2013). Exponential Random Graph Models for Social Networks. Cambridge: Cambridge university press.

Lusher, D., & Robins, G. (2013). Formation of social network structure. In D. Lusher, J. Koskinen, & G. Robins (Eds.), Exponential Random Graph Models for Social Networks (pp. 16–28). Cambridge: Cambridge University Press.

Wasserman, S., & Pattison, P. (1996). Logit models and logistic regressions for social networks: I. An introduction to Markov graphs and p*. Psychometrika, 61(3), 401–425.


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