VisitorSim: agent modeling for site management

A few years ago I developed an agent based model prototype for exploring visitor impact on archaeological sites - the idea being to model where visitors would go on a site, and to explore the consequences of alternative routings and so on. I found the presentation I made about ‘VisitorSim’ this morning, as I was looking for something else, and thought that it might be interesting to share it here. I’m interested to know if other archaeologists have ventured down this route, thoughts, ideas, etc for improving the model. I note that Keith Still, the founder of crowddynamics.com has a professional consultancy built around a similar idea, see below.

First, the VisitorSim powerpoint:

And now a page from ‘Crowd Dynamics, about the ‘Myriad II software suite’. The Venn diagram provided neatly encapsulates my own approach to ABM, networks, and archaeology; I wish I’d come across his work during my thesis years! At any rate, Myriad II looks to be an excellent piece of software, to which my VisitorSim is like a tinker-toy…

They’ve also done some analysis on historical problems:

Battlefield Detectives	Agincourt - how the battlefield geometry may have contributed to the French defeat
	Battlefield Detectives - details about the series and the book.
	Gettysburg - how the town geometry may have been a decisive factor in the battle outcome

Myriad II - Integrated Crowd Dynamics Modelling Suite

Over the last 15 years we have been using a range of modelling and analysis techniques for places of public assembly. The process of model building typically requires three different mathematical modelling disciplines. The table below shows how these methods overlap for various projects.

AGENT ANALYSIS	SPATIAL ANALYSIS	NETWORK ANALYSIS

CAA 2006 conference proceedings published

Ah! Just had a note in my email that the conference proceedings from the Computer Applications in Archaeology conference 2006, which was held in Fargo, has now been published. Full bibliographic notice:

Jeffrey T. Clark and Emily M. Hagemeister, Editors. 2007. Digital Discovery: Exploring New Frontiers in Human Heritage. CAA 2006. Computer Applications and Quantitative Methods in Archaeology. Proceedings of the 34th Conference, Fargo, United States, April 2006.Budapest:`Archaeolingua. (ISBN 978-963-8046-90-1)

The TravellerSim paper in that volume, about using agent modeling for growing social networks from regional site distribution data, was written by me with the development help of James Steiner, and presented at that conference. And now, happily, the paper and the code are published!

My thanks to Jeffrey Clark on a big job well done.

Lost Battles: Reconstructing the Great Clashes of the Ancient World

I’ve only just come across this book - and haven’t read it yet - but from the sounds of it, it looks like an application of agent based modeling to some historical problems, so probably well worth a read!

From Amazon.com

 “Ancient battles seize the modern imagination. Far from being forgotten, they have become a significant aspect of popular culture, prompting a continuing stream of books, feature films, television programs and board and computer games… there is a certain escapist satisfaction in looking back to an era when conflicts between entire states turned on clear-cut pitched battles between formed armies, lasting just a few hours and spanning just a few miles of ground. These battles were still unspeakably traumatic and grisly affairs for those involved - at Cannae, Hannibal’s men butchered around two and a half times as many Romans (out of a much smaller overall population) as there were British soldiers killed on the notorious first day of the Somme.

However, as with the great clashes of the Napoleonic era, time has dulled our preoccupation with such awful human consequences, and we tend to focus instead on the inspired generalship of commanders like Alexander and Caesar and on the intriguing tactical interactions of units such as massed pikemen and war elephants within the very different military context of pre-gunpowder warfare.

Lost Battles takes a new and innovative approach to the battles of antiquity. Using his experience with conflict simulation, Philip Sabin draws together ancient evidence and modern scholarship to construct a generic, grand tactical model of the battles as a whole. This model unites a mathematical framework, to capture the movement and combat of the opposing armies, with human decisions to shape the tactics of the antagonists. Sabin then develops detailed scenarios for 36 individual battles such as Marathon and Cannae, and uses the comparative structure offered by the generic model to help cast light on which particular interpretations of the ancient sources on issues such as army size fit in best with the general patterns observed elsewhere. Readers can use the model to experiment for themselves by re-fighting engagements of their choice, tweaking the scenarios to accord with their own judgment of the evidence, trying out different tactics from those used historically, and seeing how the battle then plays out. Lost Battles thus offers a unique dynamic insight into ancient warfare, combining academic rigor with the interest and accessibility of simulation gaming. This book includes access to a downloadable computer simulation where the reader can view the author’s simulations as well create their own.”

Philip Sabin is a prof at King’s College London’s Social Science and Public Policy School.  His website there contains more explanations and downloads connected with the book, including an extract from chapter 9. There’s a discussion group too about using his combat sim, which lives at http://groups.yahoo.com/group/lostbattles/. 

The Glooper, Agent Based Modeling, and the SAA Conference 2008 Vancouver

I received last week two interesting pieces of literature which, on the face of it, should have nothing in common: Terry Pratchet’s ‘Making Money‘ (the latest installment in his ‘Discworld’ novels) and the preliminary schedule of the Society for American Archaeology’s conference in Vancouver. The connection between the two turns on an ingenious device, central for the plot of ‘Making Money’: The Glooper.

‘Mr. Hubert believes that this… device is a sort of crystal ball for showing the future,’ said Bent, and rolled his eyes.

‘Possible futures. Would Mr. Lipstick like to see it in operation?’ said Hubert, vibrating with enthusiasm and eagerness.[...]

‘The Glooper, as it is affectionately known, is what I call a quote analogy machine unquote. It solves problems not by considering them as a numerical exercise but by actually duplicating them in a form we can manipulate: in this case, the flow of money and its effects within our society become water flowing through a glass matrix - the Glooper. The geometrical shape of certain vessels, the operation of valves and, although i say so myself, ingenious tipping buckets and flow-rate propellers enable the Glooper to simulate quite complex transactions. We can change the starting conditions, too, to learn the rules inherent in the system. For example, we can find out what happens if you halve the labour force in the city by the adjustment of a few valves, rather than by going out into the streets and killing people.’

‘A big improvement! Bravo!’ said Moist desperately, and started to clap. No one joined in.

Strangely enough, this passage is one of the best descriptions you’ll find of what agent-based models actually do (minus the water, glass beakers, tipping buckets etc), and what you can do with them. I haven’t done much with my agent modeling work of late, so reading about the Glooper almost got me charged up enough to download the latest version of Netlogo and to update/refine some models I’ve got kicking around. Which is timely, since I read almost immediately thereafter that at the SAA conference, there is a session called ‘Parallel Worlds: Interdisciplinary Agent-Based Models of Socioecological Processes and Complexity’ (scheduled for Friday March 28). Tim Kohler, Mark Lake, Luke Premo and many other excellent archaeologists-cum-agent-modelers are going to participate, so it looks like it should be a fantastic event.

I was at the CAA in Fargo a few years ago, in a session on agent-modeling, and it was interesting to observe how the agent modelers divided into two broad camps: those who tried to develop models that accounted for everything, and those who tried to develop limited models that tried to capture one specific aspect. I count myself amongst the latter: if I aim small, my results are, paradoxically, applicable to wider situations because I haven’t tried to account for everything (and thus be relevant only to what I’ve mapped). The Glooper, as it transpires in the novel, becomes such an excellent model that it maps one-to-one: changing the model changes reality.

If you’re interested in developing agent models, the learning curve can be steep. My recommendation is to download Netlogo, join the user group on Yahoo groups, do some of the tutorials (included in the documentation), and start mucking about. Other resources are here.

Tim Kohler on Agent Based Models in Archaeology

The powerpoint from Tim Kohler’s presentation of ABM for archaeology may be found here . It was part of this conference:

Agent Based Models for Spatial Systems in Social Sciences
& Economic Science with Heterogeneous Interacting Agents

(ABM–S4–ESHIA)

Agelonde, La Londe les Maures (var, France), September 17-22, 2007 (6 days).

From the look of the other presentations (scroll down, links to ppts), it looks like it was a fascinating time. I’m sorry I missed it!

Electric Archaeology: Research Notes - writers wanted!

The turn-around time for publishing research can sometimes feel like it takes ages. This isn’t - necessarily- problematic when you are publishing the results of years of study in a field that doesn’t change all that much (like my own cozy world of brick stamp studies…). But when you’re working in a field that changes monthly, if not weekly (like anything connected with digital media) by the time that article of yours comes out, it could very well be out of date. My article on agent-based modeling the Antonine Itineraries was published quite quickly, but by the time it came out the platform I used - Netlogo - had already undergone a substantial upgrade. My code was already out of date (though upgrading the model code would probably only take a day or two). I did find though that the comments and correspondence I received as a result of putting up a tatty web 1.0 website during that research were invaluable to the development of my project. I was able to put up ‘work-in-progress’ notes that generated great feedback that helped negate some of the dangers of working in a void (I was the only person in my department interested in agent modeling, at the time).

Reflecting on that experience - the lag time to final publication, and the power of many eyes looking at your work - I would like therefore to offer to anyone (especially at the senior undergrad or grad student level) who is working with digital media and archaeology or history, space on this blog to publish a series of ‘research notes’ - short articles, updates or ideas concerning their research. If you’re interested, drop me a line and I’ll set you up as an author: grahams at cc.umanitoba.ca

Slideshare and Slidecasting (and the Travellersim slideshow)

So slideshare.net has a new feature allowing the user to coordinate a podcast with a slideshow, and present it all in one neat package. Very nice. The only downside, that I can see, is that every slideshow is public. It is possible to embed a slideshare presentation into the Moodle environment, but I don’t want people not in my class to view my show back at the original slideshare website.

Here’s a sample of what a slideshare presentation looks like (my own presentation from the 2006 Congress of the Humanities at York University):

Ancient World Mapping Center

I was pleased to discover that the Ancient World Mapping Center has picked up my paper from the Journal of Mediterranean Archaeology 19.1 (2006) 25-64. The abstract from that paper is here, and some of my agent based models can be found over at my postdoc pages at the University of Manitoba.