arXiv subjects

Roger Cremades

Publications and source records attributed to Roger Cremades.

3 recordsLinked to original sources

arXiv2026

Diversification of global food trade partners increased inequalities in the exposure to shock risks

Recent global food trade disruptions have evidenced how local shocks can cascade into global security threats. While the capacity of food systems to absorb spillovers depends heavily on its underlying trade networks, few studies quantify how their temporal evolution reshapes systemic vulnerability over time. Here, we evaluate how changes in global connectivity from 1986 to 2022 reshaped responses to production shocks. Using FAO data, we built yearly multiplex representations of the food trade system and quantified robustness through a stochastic shock-propagation model with dynamic export bans. We find that while increasing globalization intensified inter-dependencies and amplified cascades, robustness trends remain heterogeneous. Grain trade has become more decentralized and resilient to targeted shocks; conversely, Animal and Vegetable Fats exhibit growing centralization and fragility around key exporters like Indonesia and Malaysia. These structural transformations caused diverging shifts in systemic vulnerability, disproportionately threatening already vulnerable regions such as Africa and Southern Asia.

physics.soc-ph↗

arXiv2025

Large Language Models for Agent-Based Modelling: Current and possible uses across the modelling cycle

The emergence of Large Language Models (LLMs) with increasingly sophisticated natural language understanding and generative capabilities has sparked interest in the Agent-based Modelling (ABM) community. With their ability to summarize, generate, analyze, categorize, transcribe and translate text, answer questions, propose explanations, sustain dialogue, extract information from unstructured text, and perform logical reasoning and problem-solving tasks, LLMs have a good potential to contribute to the modelling process. After reviewing the current use of LLMs in ABM, this study reflects on the opportunities and challenges of the potential use of LLMs in ABM. It does so by following the modelling cycle, from problem formulation to documentation and communication of model results, and holding a critical stance.

cs.MA↗

arXiv2023

Vulnerability of democratic electoral systems

The two most common types of electoral systems (ES) used in electing national legislatures are proportional representation and plurality voting. When they are evaluated, most often the arguments come from social choice theory and political sciences. The former overall uses an axiomatic approach including a list of mathematical criteria a system should fulfill. The latter predominantly focuses on the trade-off between proportionality of apportionment and governability. However, there is no consensus on the best ES, nor on the set of indexes and measures that would be the most important in such assessment. Moreover, the ongoing debate about the fairness of national elections neglects the study of their vulnerabilities. Here we address this research gap with a framework that can measure electoral systems' vulnerability to different means of influence. Using in silico analysis we show that plurality voting systems are less stable than proportional representation. They are also more susceptible to political agitators and media propaganda. A review of real-world ES reveals possible improvements in their design leading to lower susceptibility. Additionally, our simulation framework allows computation of popular indexes, as the Gallagher index or the effective number of parties, in different scenarios. Our work provides a new tool for dealing with modern threats to democracy that could destabilize voting processes. Furthermore, our results add an important argument in a long-standing discussion on evaluation of ES.

physics.soc-ph↗