KAROLINE WIESNER, JYOTSNA PURI, and ANDREAS REUMANN

Advances in Complex SystemsVol. 27, No. 06, 2440004 (2024)

As governments and multilateral institutions launch projects and programs to support climate change mitigation and adaptation, the challenge lies in determining their effectiveness. The high complexity of climate-change programs often makes it difficult to determine their effectiveness through standard monitoring and evaluation procedures. ‘complexity-aware monitoring’ is a qualitative approach to monitoring, recently introduced by international development programs. This increasing awareness of complexity in the evaluation sector opens up a window of opportunity for complexity science to support climate change mitigation and adaptation programs. This paper’s contribution is a hands-on methodology for live monitoring and evaluation of development programs. The methodology is rooted in existing literature on social–ecological systems, as pioneered by Ostrom, and in quantitative methods from complexity science. To illustrate the methodology, an existing climate mitigation project in Madagascar, funded, monitored and evaluated by the Green Climate Fund, is discussed.

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Arke Vogell, Udo Schilcher, Jorge F. Schmidt, and Christian Bettstetter

Phys. Rev. E 110, 054214

Coupled oscillator systems can lead to states in which synchrony and chaos coexist. These states are called “chimera states.” The mechanism that explains the occurrence of chimera states is not well understood, especially in pulse-coupled oscillators. We study a variation of a pulse-coupled oscillator model that has been shown to produce chimera states, demonstrate that it reproduces several of the expected chimera properties, like the formation of multiple heads and the ability to control the natural drift that Kuramoto’s chimera states experience in a ring, and explain how chimera states emerge. Our contribution is defining the model, analyzing the mechanism leading to chimera states, and comparing it with examples from the field of Kuramoto oscillators.

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Philippe Collard

Artificial Life (2024) 30 (2): 171–192.

This article deals with individuals moving in procession in real and artificial societies. A procession is a minimal form of society in which individual behavior is to go in a given direction and the organization is structured by the knowledge of the one ahead. This simple form of grouping is common in the living world, and, among humans, procession is a very circumscribed social activity whose origins are certainly very remote. This type of organization falls under microsociology, where the focus is on the study of direct interactions between individuals within small groups. In this article, we focus on the particular case of pine tree processionary caterpillars (Thaumetopoea pityocampa). In the first part, we propose a formal definition of the concept of procession and compare field experiments conducted by entomologists with agent-based simulations to study real caterpillars’ processionaries as they are. In the second part, we explore the life of caterpillars as they could be. First, by extending the model beyond reality, we can explain why real processionary caterpillars behave as they do. Then we report on field experiments on the behavior of real caterpillars artificially forced to follow a circular procession; these experiments confirm that each caterpillar can either be the leader of the procession or follow the one in front of it. In the third part, by allowing variations in the speed of movement on an artificial circular procession, computational simulations allow us to observe the emergence of unexpected mobile spatial structures built from regular polygonal shapes where chaotic movements and well-ordered forms are intimately linked. This confirms once again that simple rules can have complex consequences.

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