New publication: sensitivity analysis in archaeological simulation

Read about the necessary but terrifying process of having our MERCURY model replicated. How robust were our previously published results? Hilde Kanters’ excellent work! With Iza Romanowska and myself.

Read the open access paper here https://www.sciencedirect.com/science/article/pii/S2352409X21001863

Jeroen Poblome and I published the MERCURY model in 2016 https://doi.org/10.15184/aqy.2016.35… We performed a selected set of experiments that allowed us to explore the model’s behaviour. But how robust were the results that we published there?

Our original experiments suggested that weak market integration (low availability of reliable non-local information), equal production capacities of pottery manufacturers, and equal demands at settlements throughout the roman world were unlikely to explain tableware distributions. We came to these conclusions by performing 34 experiments where we changed the relevant parameters of the MERCURY model that represented key explanatory factors. These experiment settings are shown in detail in our 2016 paper in JASSS: http://dx.doi.org/10.18564/jasss.2953

34 experiments is pretty good for an archaeological model, I tell myself. And certainly they suggest how the model behaves. But they do not reflect the full range of theoretically possible scenarios: we did not originally explore the full possible parameter space.

In comes the fantastic Hilde Kanters, who independently performed a replication of the MERCURY model in Repast Symphony (the original was coded in Netlogo) using only our publications. Her MSc thesis at Leiden University. Imagine my terror/excitement when I heard.

The replication study came to substantively the same conclusions as we did *massive sigh of relief* and made some very critical but constructive recommendations *massive collegial handshake*

This replication study is available open access https://studenttheses.universiteitleiden.nl/handle/1887/68248

The replication was made possible because not only did we publish the technical side of the model in detail in JASSS but mainly because we made the model code openly available on Comses OpenABM https://comses.net/codebases/4347/releases/1.1.0/

We were so impressed with Hilde Kanters’ work and delighted when the opportunity arose for her to do an internship in project MERCURY when I was at UBICS in Barcelona (such a great place to be as a complexity scientist). And Iza Romanowska luckily co-supervised this internship, which really set it up for excellent outputs. But what to do? I had loads of fun ideas to expand MERCURY: transport routes, equilibrium model, pots in spaaaaaaaaaice.

But in the end we knew we needed to do the responsible thing: check how robust the previously published results of MERCURY were by exploring the parameter space. We did a sensitivity analysis! See the results in our new paper in JASR. We now understand the model so much better, and I can be very confident of two key conclusions: the explanatory power of limited availability of reliable non-local information, and of strong differences in production capacity. But crucially, the sensitivity analysis also revealed I should be more cautious about the explanatory power of differences in demand throughout the Roman world: this was a new unexpected result, and will inform how I develop MERCURY in the future for sure.

Another thing that became painfully clear when working on this paper was the sad fact that ARCHAEOLOGISTS DON’T DO SENSITIVITY ANALYSES… But hey, we can help you on your way. We published a script for performing sensitivity analyses of ABM that can be reused by anyone, hurray! https://zenodo.org/record/4741208

Read more in the paper: https://www.sciencedirect.com/science/article/pii/S2352409X21001863

Abstract

Computational modelling is increasingly gaining attention in archaeology and related disciplines. With the number of new models growing it is often difficult to evaluate their significance and the generality of the results. This is partially due to the narrow reporting of the model’s results, which are often limited to those directly relevant to the research question posed in the first place. Although this is not an issue per se, models, if explored exhaustively, can provide a much wider perspective on the studied system. Sensitivity analysis is a widely recognised model exploration method for assessing the importance of different parameters on the model’s behaviour. Such systematic exploration helps in unravelling the dynamics that drive the model and enable researchers to establish how robust the presented results are. Here we present a sensitivity analysis of MERCURY, a previously published archaeological agent-based model. The results show that two out of three of the original conclusions drawn on the basis of selective experiment design stand up to scrutiny. By describing in detail and providing a reusable script with detailed description of all steps of the sensitivity analysis we hope to promote this important model exploration technique among modellers and the wider archaeological audience.

Our new publication in JAMT: over half a million pot sherds from Jerash and simulation

Really delighted to announce that our latest paper was recently published open access online in the Journal of Archaeological Method and Theory. It’s the result of years of collaborating between excavators, ceramics specialists and simulation experts. We analysed over half a million ceramics sherds from Jerash (ancient Gerasa, in Jordan), and identified that over 99% of the stuff was locally produced. What really excited me in this collaboration was the discrepancy between this proportion and the tendency for classical archaeologists (including myself) to always focus on imports.

Read the open access paper here.

The proportion of locally produced, regional and imported pottery for (left: ‘total’) all excavated ceramics (n = 625,063; excludes 133,584 topsoil entries), (middle) three securely dated trenches closed by the earthquake event of AD 749 (K n = 10 006; P n = 2184; V n = 10 614) and (right) three trenches consisting of ancient olive oil press installations filled in with ceramics (B n = 58 751; J n = 144 390; N n = 71 555)

Caption feature image: The Jerash Northwest Quarter excavations with trench letters (© Danish-German Jerash Northwest Quarter Project)

Why are there so many locally produced ceramics in Jerash, and so few regional and imported ones? This new publication quantitatively analyses the more than half a million sherds that were recorded by the Danish-German Jerash Northwest Quarter Project, and discusses different answers to this question. I applies innovative simulation techniques to evaluate whether personal preference for local Jerash products might have played a role. The result? The authors show that three ways of conceptualising preference for the local product might explain the ceramic data pattern, but other theories of preference are less good explanations.

Abstract

The Danish-German Jerash Northwest Quarter Project revealed a robust and striking pattern of the extreme dominance (>99%) of locally produced ceramics over six centuries and across different depositional contexts (in total over half a million pottery sherds). The archaeology of Jerash points towards an exceptional degree of self-sufficiency in craft products: why? The project team implemented a full quantification approach during excavation, manually and digitally recording and counting all pottery and other classes of artefacts. This enabled a full analysis of trends in production and use of ceramics throughout the archaeologically documented history of Jerash and revealed the unexpected pattern of the extreme dominance of local pottery. Archaeologists formulated a set of hypotheses to explain this pattern, and we developed an agent-based model of simple customer preference driving product distribution to evaluate several explanatory factors and their potential interactions. Our simulation results reveal that preference for locally produced ceramics at Jerash might be a plausible theory, but only if its intrinsic value was considered rather high in comparison to other goods, or if it was preferred by a majority of the population, and there was a tendency to follow this majority preference (or a combination of these factors). Here, we present a complete research pipeline of a full quantification of ceramics, analysis and modelling applicable at any archaeological site. We argue that transparent methods are necessary at all stages of an archaeological project: not only for data collection, management and analysis but also in theory development and testing. By focusing on a common archaeological material and by leveraging a range of widely available computational tools, we are able to better understand local and intra-regional distribution patterns of craft products in Jerash and in the ancient eastern Mediterranean.

Results of different simulation experimental setups. Each boxplot represents how close the simulated proportions of local, regional and imported ceramics are to the archaeologically observed ceramics (100 repetitions; 500 time steps; 100 agents)

Job: postdoc ABM Ancient Egypt

The following job might be of interest to readers of this blog:

http://www.nitschke-lab.uct.ac.za/nitschke/positions

Postdoctoral Position : Agent-Based Modeling of Social Complexity in Ancient Egypt

An interdisciplinary (social science, computational archaeology, and machine learning) two (2) year postdoctoral research fellowship for agent-based modeling and simulation is currently available at the Department of Computer Science, University of Cape Town.

The postdoctoral fellow will work on an interdisciplinary agent-based modeling (ABM) and simulation project that investigates the emergence of social complexity in early Egypt. The project proposes to develop the ABM as an experimental computational platform for studying and analyzing complex system behaviour, in this case, the evolution of societal complexity. The ABM will be used to design experiments that examine the social dynamics of early Egypt, including the emergence of entrenched inequality, urbanism, social hierarchy, networks, and ideology of kingship. The goal is to explore how the Egyptian state emerged as a
result of the meaningful actions of individuals pursuing their own interests within the particular environmental conditions of the Nile
Valley in the fourth millennium BC, as well as compare this system to similar case studies in social complexity in Africa more broadly.

As part of the process of developing the ABM, the fellow will be expected to conduct research on the modeling of emergent complexity in agent-based models of ancient societies, including the application of evolutionary machine learning to simulate adaptive behaviour. Ideally the ABM design principles will take inspiration from the relevant social complexity literature and prevailing theories of emergent complexity.  However, the exact focus of the project will be jointly decided by the postdoctoral fellow and supervisors.

The candidate will have the opportunity to collaborate with the interdisciplinary network of researchers at the Evolutionary Machine
Learning Group, University of Cape Town, the Department of Ancient Studies, Stellenbosch University, and the Department of Archaeology, University of Cape Town. In addition to research, candidate is expected to co-supervise graduate students within this network of researchers.
Requirements:

  • PhD (or nearly completed) degree in computational archaeology, computer science, or a closely related field.
  • Good programming skills (Java, Python, Net Logo or other agent-based modeling languages).
  • Excellent communication skills, in both spoken and written English, and the ability to work independently.
  • Expertise in agent-based modeling and simulation.
  • Some expertise in evolutionary machine learning would be advantageous.
  • Candidates with a background in computational archaeology who are willing to acquire machine learning expertise during the postdoc, are encouraged to apply.

Deadlines and More Information:

Starting date is flexible: From February 1, 2020.

Applications will be evaluated on a first-come-first-serve basis, and will continue to be received and reviewed from December 1, 2019 until the position is filled.

New resource: ABM in archaeology bibliography

Agent-based modelling is no longer a niche pursuit in archaeology. It’s a thriving sub-discipline with an active community engaged in developing original methods and software to tackle a varied range of archaeological research topics. This is reflected in a new bibliography project by the SimulatingComplexity team, and in particular Iza Romanowska and Lennart Linde. They compiled all published cases they could find in a structured Github archive. Everyone is invited to add missing publications to the corpus!

Find the bibliography here.

Check our SimulatingComplexity.

Workshop in Ottawa tomorrow

networks-simulation-workshop-imageIza Romanowska and I have spent the last few weeks at Carleton University in Ottawa, Canada, doing some awesome Roman networky boardgame “research” with Shawn Graham. You’ll hear more about this cool work soon. Tomorrow we will give a workshop on simulation and networks for the humanities. If you happen to be in the neighbourhood, swing by! If not, get in touch if you are interested and I will share the workshop tutorials with you.

Carleton University, Ottawa, Macodrum Library Discovery Centre RM 481, 11 – 2

networks-simulation-workshop-imageUnderstanding the complexity of past and present societies is a challenge across the humanities. Simulation and network science provide computational tools for confronting these problems. This workshop will provide a hands-on introduction to two popular techniques, agent based modeling and social network analysis. The workshop has been designed with humanities students in mind, so no prior computer experience required.

The workshop is led by Tom Brughmans and Iza Romanowska of University of Konstanz and the University of Southampton, two of the leading digital archaeologists. Brughmans is co-editor of the recent volume, ‘The Connected Past: Challenges to Network Studies in Archaeology and History‘ published by Oxford University Press. Romanowska edits the scholarly blog ‘Simulating Complexity‘ and is a Fellow of the Software Sustainability Institute where she promotes the use of computational methods in the humanities.

2-day ABM workshop

abm

If you want to learn how to use networks in an ABM environment then join this free 2-day workshop. A lot of ABM related topics will be taught, including networks. So sign up! More info below and in this leaflet.

Agent-based modelling (ABM) has taken by storm disciplines from all corners of the scientific spectrum, from ecology to medical research and social sciences and it is becoming increasingly popular in archaeology.
Now it is your turn to give it go!
Learn how to use the simulation software and explore how this popular complexity science technique can complement your research. This two-day workshop will provide an introduction to ABM using NetLogo – an open-source platform for building agent-based models, which combines user-friendly interface, simple coding language and a vast library of model examples, making it an ideal starting point for entry-level agent-based modellers, as well as a useful prototyping tool for more experienced programmers.
For more details see the Workshop leaflet.
To secure a place please send an email to i.romanowska at soton.ac.uk<http://soton.ac.uk> expressing your interest and briefly describing your background and the reasons why you want to attend. The event is free of charge, but you need to register to the CAA conference. Please note that places are limited and early applications will be given preference.
If you are:
an undergraduate, master or PhD student in archaeology, anthropology, history or a similar subject, an early career researcher, a lecturer, a commercial archaeologists or a heritage specialist
and if
● you are interested in computational modelling and simulations, or
● you work on a complex problem which can only be solved by modelling, or
● your supervisor told you to ‘go an learn how to do simulations’, or
● your students seem to be doing some magic with computers and you want to
help them but don’t know the tools, or
● you have once heard of agent-based modelling so you want to check what is
the whole fuss about, then this workshop is for you!
What will you learn?
● the theory and practice of agent-based modelling;
● how to create an archaeological simulation;
● basic and intermediate programming skills in NetLogo;
● the modelling process, from finding the right research questions to publishing your groundbreaking results;
● how to make your code better, clearer and faster;
● NetLogo extensions incorporating GIS, network science, and stats.
Coding experience is NOT required.
You need to bring your own laptop.

Livestream Crabtree seminar Tuesday

crabtree_webNext Tuesday (21-01-2014) Stefani Crabtree will give a talk entitled ‘A Tale of Two Villages: How Food Exchange Led to Aggregation in the American Southwest’ in the Archaeological Computing Research Group here in Southampton. This talk will be livestreamed via this URL, so no reason not to watch this promising talk! Stef’s work will be of interest to all of us who love their networks, adore agent-based-modelling, have a passion for the archaeology of the US Southwest … or those who just enjoy a great talk by an inspiring researcher.


When? Tuesday 21 January 2014 5pm GMT
Where? Southampton and online!
Livestream URL
Stefani’s abstract is attached below, and have a look at the poster for her talk by clicking on the image above.

Want to know more about the research done at the Archaeological Computing Research Group? We’ve been pretty good in sharing our work on our group’s blog lately, so check it out there!

In this talk I use computer simulation to explore the extent to which food-sharing practices would have been instrumental for the survival of Ancestral Pueblo people across the patchy landscape of the Prehispanic American Southwest. Social networks would have created stable bonds among these exchanging individuals, further helping the survival of those individuals and their progeny. Specifically, I engage Sahlins’s notion of balanced reciprocal exchange networks (BRN; when unrelated individuals rely upon reputation building to inform exchange relationships) within the experimental test-bed of the Village Ecodynamics Project’s agent-based simulation.

CFP Simulating The Past

simulpastA really interesting conference is coming up: Simulating the past in Barcelona, 1-5 September 2014. Organised by the Simulpast project with keynote speakers Tim Kohler and Joshua Epstein. The call for papers is open until February 28 2014. More info below and on the Simulpast website.

From September 1st to 5th, 2014, the European Social Simulation Association  (http://www.essa.eu.org/) will celebrate its annual meeting in Barcelona (Spain), at the Universitat Autònoma de Barcelona  (www.uab.cat):

SOCIAL SIMULATION-2014

http://www.essa2014.eu/

On that occasion there will be the satellite conference, organized in collaboration with the Computer Applications and Quantitative Methods in Archaeology Society (http://caaconference.org/about/):

SIMULATING THE PAST TO UNDERSTAND HUMAN HISTORY

The conference is organized with the contribution of the SimulPast project (www.simulpast.es), a 5-year exploratory research project funded by the Spanish Government (MICINN CSD2010-00034) that aims at developing an innovative and interdisciplinary methodological framework to model and simulate ancient societies and their relationship with environmental transformations. To achieve these aims, SimulPast integrates knowledge from diverse fields covering humanities, social, computational and ecological sciences within a national and international network.

The conference intention is to showcase the result of the SimulPast project together with current international research on the methodological and theoretical aspects of computer simulation in archaeological and historical contexts. The conference will bring together scholars from different disciplinary backgrounds (history, ecology, archaeology, anthropology, sociology, computer science and complex systems) in order to promote deeper understanding and collaboration in the study of past human behavior and history.

The topics of interest include, but are not limited to:

  • Applications of computational modeling in archaeology and history
    • Social organization and change
    • Cultural transmission and evolution
    • Long term socio-ecology
    • Human adaptation and climate change
    • Cooperation and warfare
    • Trade and exchange

 

  • Tools and methods for development of simulation models
    • Calibration and validation
    • Realistic vs abstract modeling
    • Results analysis and verification
    • Simulation software & programming computational frameworks

 

Applications are welcomed on all subjects (from Anthropology, Archaeology, Geography and History) using different approaches to social simulation and presenting case studies from any region of the world and any prehistoric or historic period. Theoretical aspects of social and cultural evolution are also encouraged.

For more information do not hesitate to contact the local organizers (juanantonio.barcelo@uab.cat). Detailed information, EasyChair links for submissions and registration will be available at:    http://www.essa2014.eu/

Given the coincidence with Union Internationale des Sciences Prehistoriques et  Protohistoriques Meeting in Burgos (Spain) (http://www.burgos2014uispp.com), every effort will be made in order to allow interested researchers to assist to both Conferences. Burgos is well connected with Barcelona by plane (from Valladolid) or by train.

CfP CAA2014 S25. “Agents, Networks, Equations and Complexity: the potential and challenges of complex systems simulation”

CAA headerApologies for cross-posting!

Dear all,

We would like to draw your attention to a session on complex systems simulation in archaeology as part of the Computer Applications and Quantitative Methods in Archaeology (CAA) conference in Paris, France, this April.

If you have created a computational model (Agent-based, mathematical, statistical, network analysis) within the broad topic of complex systems in archaeology, developed a new technique or particularly innovative solution to one of the recurrent issues in modelling, if you think you might have some new insights into the theoretical underpinnings of using simulations and complexity science in archaeology then we would like to hear more about it
We are organising a session on complex systems and computational models in archaeology: “S25. Agents, Networks, Equations and Complexity: the potential and challenges of complex systems simulation”. We hope to bring together a wide variety of researchers working on a diverse case studies using techniques from all spectrum of complexity science. The goal of this session is to showcase the best applications, discuss the potential and challenges and sketch out the long-term outlook for applications of simulation techniques in archaeology. For further information see the abstract below.

The call for papers closes on the 31st of October 2013. To submit an abstract, please, go to this website, create your user account, click on ‘submissions’ under the heading ‘My Space’ in the left hand side menu and follow the instructions on screen. Please do not forget to choose “S25. Agents, Networks, Equations and Complexity: the potential and challenges of complex systems simulation” from the dropdown menu “Topic”.

We will also be running a workshop on computational modelling in archaeology, which you are all welcome to join. More information about the workshop will follow in January when the workshop registration will open.

Hope to see you in Paris.
Best wishes,

Ben, Iza, Enrico, Tom

Ben Davies (Department of Anthropology, University of Auckland)
Iza Romanowska (Institute for Complex Systems Simulation, University of Southampton)
Enrico Crema (Institute of Archaeology, University College London)
Tom Brughmans (Archaeological Computing Research Group, University of Southampton)

SESSION ABSTRACT

S25 Agents, Networks, Equations and Complexity: the potential and challenges of complex systems simulation

Chairs : Benjamin Davies 1, Iza Romanowska 2, Enrico Crema 3, Tom Brughmans 2

1 : The University of Auckland – Website
2 : University of Southampton – Website
3 : University College London – Website

Simulation is not new in archaeology. However, the last decade knew an increased focus among archaeologists in the use of simple computational models used to evaluate processes which may have operated in the past. Rather than all-encompassing reconstructions of the prehistoric world, models have been used as ‘virtual labs’ or ‘tools to think with’, permitting archaeologists to explore hypothetical processes that give rise to archaeologically attested structures. Computational modelling techniques such as equation-based, statistical, agent-based and network-based modelling are becoming popular for quickly testing conceptual models, creating new research questions and better understand the workings of complex systems. Complexity science perspectives offer archaeology a wide set of modelling and analytical approaches which recognise the actions of individual agents on different scales who collectively and continually create new cultural properties.

This session aims to bring together complex systems simulation applications in archaeology. We invite innovative and critical applications in analytical and statistical modelling, ABM, network analysis and other methods performed under the broad umbrella of complexity science. We hope this session will spark creative and insightful discussion on the potentials and limitations of complexity science, its many simulation techniques and the future of modelling in archaeology.

ABM workshop at CAA 2013

CAAworkshop_complexity_leafletI will be involved in an awesome workshop on agent-based modelling in Archaeology at CAA 2013 in Perth. Sound interesting? Hell yeah! Read the outline below and feel free to register you interest. Click here or on the image to the left to check out our awesome flyer (courtesy of Iza Romanowska).

Dear all,

We would like to draw your attention to a workshop on agent-based modelling in archaeology as part of the Computer Applications and Quantitative Methods in Archaeology (CAA) conference

Ever wondered what all this complex systems talk in archaeology is about, or how to design your own sophisticated simulation model? Then this might be for you:

We will organise a workshop on complex systems and agent-based simulations models in archaeology at the CAA Conference in Perth, Australia, this March. Places are still available but Early Bird Registration to the conference ends on Thursday February 7th, so hurry up to get a discount! The workshop itself is free of charge.

The workshop will take place on Monday March 25th and will consist of a morning and an afternoon session. At the end of the day you will be able to design and program your own simulation model to help you answer your research questions in archaeology or related social sciences – guaranteed …

Registration for the conference at:

http://www.caa2013.org/drupal/registration

Registration to the workshop will be announced on the CAA website soon, but you can already reserve a seat by contacting Carolin at cv275@cam.ac.uk

For further information see the abstract below. A flyer with a detailed programme is attached.

Hope to see you there.

Best wishes,

Carolin, Iza, Tom and Eugene

Carolin Vegvari (Department of Biological Anthropology, University of Cambridge)
Iza Romanowska (Institute for Complex Systems Simulation, University of Southampton)
Tom Brughmans (Archaeological Computing Research Group, University of Southampton)
Eugene Ch’ng (IBM Visual and Spatial Technology Centre, University of Birmingham)

WORKSHOP ABSTRACT

W1: Complex Systems and Agent-Based Modelling in Archaeology
Chairs: E. Ch’ng, C. Vegvari
Discussants: I. Romanowska, T. Brughmans

Modelling in various forms has always been an integral part of archaeology. In the broadest sense, archaeology is the study of human activities in the past, and a model is a simplified representation of reality. As a map is a useful abstract of the physical world that allows us to see aspects of the world we chose to, so a computational model distils reality into a few key features, leaving out unnecessary details so as to let us see connections. Human societies in their environmental context can be considered as complex systems. Complex systems are systems with many interacting parts, they are found in every hierarchy of the universe, from the molecular level to large planetary systems within which life and humanity with its cultural developments occur. Formal modelling can help archaeologists to identify the relationships between elements within a complex socio-environmental system in that particular hierarchy. Simulating large populations and non-linear interactions are computationally expensive. In recent years, however, the introduction of new mathematical techniques, rapid advances in computation, and modelling tools has greatly enhanced the potential of complex systems analysis in archaeology. Agent-Based Modelling (ABM) is one of these new methods and has become highly popular with archaeologists. In Agent-Based Modelling, human individuals in ancient societies are modelled as individual agents. The interaction of agents with each other and with their environment can give rise to emergent properties and self-organisation at the macro level – the distribution of wealth within a society, the forming of cohesive groups, population movements in climate change, the development of culture, and the evolution of landscape use are among the examples. Thus, the application of Agent-Based Models to hypothesis testing in archaeology becomes part of the question. The ability to construct various models and run hundreds of simulation in order to see the general developmental trend can provide us with new knowledge impossible in traditional approaches. Another advantage of agent-based models over other mathematical methods is that they can easily model, or capture heterogeneity within these systems, such as the different characteristics (personalities, gender, age, size, etc), preferences (coastal, in-land, food, fashion), and dynamics (microstates of position and orientation).

We would like to invite archaeologists new to complex systems and Agent-Based Modelling for an introductory workshop on Complex Systems and Agent-Based Modelling in archaeology. The workshop introduces the concept of Complexity in archaeology, drawing relationships between Information, Computation and Complexity. The practicality of the workshop leads beginners in building simple agent- based models and provides a means to build more complex simulations after. Participants knowledgeable in Complexity wishing to gain insights on real-world applications of Complexity will benefit from this workshop. Participants will get the opportunity to experiment with simple models and draw conclusions from analysis of simulations of those models. Programming experience is not required as the workshop leads beginners from the ground up in modelling tools.

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