Xavier Rubio-Campillo

Scalable agent-based modelling with cloud HPC resources for social simulations

New concepts like agent-based modelling are providing social scientists with new tools, more suited to their background than other simulation techniques. The success of this new trend will be strongly related to the existence of simulation tools capable of fulfilling the needs of these disciplines. Given the computational requirement of realistic agent-based models, high-performance computing infrastructure is often necessary to perform the calculations. At present, such resources are unlikely to be available to humanities researchers. Having developed Pandora, an open-source framework designed to create and execute large-scale social simulations in high-performance computing environments, this work presents an evaluation of the impact of cloud computing within this context. We find that the constraints of the cloud environment do not have a significant impact on the generic pattern of execution, providing a cost-effective solution for social scientists.

The development of new infantry tactics during the early eighteenth century: a computer simulation approach to modern military history

Computational models have been extensively used in military operations research, but they are rarely seen in military history studies. The introduction of this technique has potential benefits for the study of past conflicts. This paper presents an agent-based model (ABM) designed to help understand European military tactics during the eighteenth century, in particular during the War of the Spanish Succession. We use a computer simulation to evaluate the main variables that affect infantry performance in the battlefield, according to primary sources. The results show that the choice of a particular firing system was not as important as most historians state. In particular, it cannot be the only explanation for the superiority of Allied armies. The final discussion shows how ABM can be used to interpret historical data, and explores under which conditions the hypotheses generated from the study of primary accounts could be valid.

When Knowledge Follows Blood: Kin Groups and the Distribution of Traditional Ecological Knowledge in a Community of Seminomadic Pastoralists, Gujarat (India)

Understanding the patterns and processes underlying the heterogeneous distribution of traditional ecological knowledge (TEK) across communities of natural resource users is a growing research topic. However, social organization as a factor potentially shaping TEK intracultural distribution has received scant attention. Here, we analyze the role played by kinship groups—namely, patrilineal lineages and segments—in shaping bodies of TEK among a group of seminomadic pastoralists in India. We use two quantitative approaches (score based and similarity based) to analyze variations in four TEK domains: soils, ethnoveterinary, breeds, and ethnobotany. We find that kinship groups share divergent bodies of knowledge, a finding that we interpret in light of the social organization of migration, in which kinship provides a privileged basis that structures migratory groups and, as such, favors the constitution of shared bodies of knowledge. We conclude by advocating for a better inclusion of the organizational featur...

Model Selection in Historical Research Using Approximate Bayesian Computation

Formal Models and History Computational models are increasingly being used to study historical dynamics. This new trend, which could be named Model-Based History, makes use of recently published datasets and innovative quantitative methods to improve our understanding of past societies based on their written sources. The extensive use of formal models allows historians to re-evaluate hypotheses formulated decades ago and still subject to debate due to the lack of an adequate quantitative framework. The initiative has the potential to transform the discipline if it solves the challenges posed by the study of historical dynamics. These difficulties are based on the complexities of modelling social interaction, and the methodological issues raised by the evaluation of formal models against data with low sample size, high variance and strong fragmentation. Case Study This work examines an alternate approach to this evaluation based on a Bayesian-inspired model selection method. The validity of the classical Lanchester’s laws of combat is examined against a dataset comprising over a thousand battles spanning 300 years. Four variations of the basic equations are discussed, including the three most common formulations (linear, squared, and logarithmic) and a new variant introducing fatigue. Approximate Bayesian Computation is then used to infer both parameter values and model selection via Bayes Factors. Impact Results indicate decisive evidence favouring the new fatigue model. The interpretation of both parameter estimations and model selection provides new insights into the factors guiding the evolution of warfare. At a methodological level, the case study shows how model selection methods can be used to guide historical research through the comparison between existing hypotheses and empirical evidence.

Comigrants and friends: Informal networks and the transmission of traditional ecological knowledge among seminomadic pastoralists of Gujarat, India

Previous research has shown that social organization may affect the distribution of traditional ecological knowledge (TEK) within local communities of natural resource users in multiple ways. However, in this line of research the potential role of informal relationships has mostly been overlooked. In this article, we contribute toward filling this research gap by studying how two types of informal relationships, namely migration partnership and friendship, affect the distribution of TEK within a community of seminomadic pastoralists from the Kutch area, Gujarat, India. Using social network analysis, we map three networks, migration, men friendship, and women friendship, and compare with similarity-based quantitative approaches the clusters extracted from these networks in relation to four domains of TEK: knowledge about soils, about ethnoveterinary practices, about sheep breeds, and in ethnobotany. Our results show that (1) migration clusters are associated to significant variations in three TEK domains, while (2) friendship clusters are associated to minor variations. We relate these results to the importance of common practical experiences involved by joint migration. Moreover, kin relations are shown to strongly underlie friendship and migration relations, and as such appear as a potential driver of the dynamics of the local TEK system. We conclude by advocating for a better inclusion of such informal relationships in future research on local TEK dynamics, following recent developments in studies on natural resource governance.

Quantum Probabilistic Description of Dealing with Risk and Ambiguity in Foraging Decisions

A forager in a patchy environment faces two types of uncertainty: ambiguity regarding the quality of the current patch and risk associated with the background opportunities. We argue that the order in which the forager deals with these uncertainties has an impact on the decision whether to stay at the current patch. The order effect is formalised with a context-dependent quantum probabilistic framework. Using Heisenbergs uncertainty principle, we demonstrate the two types of uncertainty cannot be simultaneously minimised, hence putting a formal limit on rationality in decision making. We show the applicability of the contextual decision function with agent-based modelling. The simulations reveal order-dependence. Given that foraging is a universal pattern that goes beyond animal behaviour, the findings help understand similar phenomena in other fields.

Military reconstructive simulation in the cloud to aid battlefield excavations

Archaeological studies on battlefields may see great benefits from simulated military engagements: simulations help testing hypotheses based on historical data and may also help with validating methodologies used on the site. Such methods, however, require high-performance computing expertise and considerable computational power. With the emergence of on-demand computing instances in the cloud, distributed computations have become available to technically every organization or individual. This puts large-scale battlefield simulations within the reach of archaeologists, and the cloud paradigm also lowers the required technological expertise, potentially leading to a more widespread adoption of such simulation methods.

The study of spatiotemporal patterns integrating temporal uncertainty in late prehistoric settlements in northeastern Spain

This paper explores the integration of two variables that are typically difficult to use in spatial analysis: time and uncertainty. A framework is constructed to analyse mid- and long-term variation in settlement dynamics during late prehistory in northeastern Spain. Following previous proposals, an aoristic model is built with ceramic dating to feed a Monte Carlo simulation that explores the case study using a discrete time-step approach. At the same time, available radiometric dating is used to validate the accuracy of the simulation results. Departing from the static analysis of spatial variables, the model proposes a new approach by which researchers can address temporal uncertainty. The results show that patterns detected by classical spatial analysis can be produced by artefacts derived from the division of time in chronological units instead of discrete time periods. The model is also used to compare a priori identical variations whose rate of change, when analysed with this approach, is revealed to be completely different.

Bayesian analysis and free market trade within the Roman Empire

Abstract The trade networks of the Roman Empire are among the most intensively researched large-scale market systems in antiquity, yet there is no consensus on the economic structure behind this vast network. The difficulty arises from data fragmentation and the lack of formal analytical methods. Here, the authors present a Bayesian analysis quantifying the extent to which four previously proposed hypotheses match the evidence for the market system in Roman olive oil. Results suggest that the size of economic agents involved in this network followed a power-law distribution, strongly indicating the presence of free market structures supplying olive oil to Rome. This new analysis offers an important tool to researchers exploring the impact of trade on the dynamics of past societies.

Multilevel processes and cultural adaptation: Examples from past and present small-scale societies

Cultural adaptation has become central in the context of accelerated global change with authors increasingly acknowledging the importance of understanding multilevel processes that operate as adaptation takes place. We explore the importance of multilevel processes in explaining cultural adaptation by describing how processes leading to cultural (mis)adaptation are linked through a complex nested hierarchy, where the lower levels combine into new units with new organizations, functions, and emergent properties or collective behaviours. After a brief review of the concept of cultural adaptation from the perspective of cultural evolutionary theory and resilience theory, the core of the paper is constructed around the exploration of multilevel processes occurring at the temporal, spatial, social and political scales. We do so by examining small-scale societies case studies. In each section, we discuss the importance of the selected scale for understanding cultural adaptation and then present an example that illustrates how multilevel processes in the selected scale help explain observed patterns in the cultural adaptive process. We end the paper discussing the potential of modelling and computer simulation for studying multilevel processes in cultural adaptation.