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Casper van Elteren

Publications and source records attributed to Casper van Elteren.

6 recordsLinked to original sources

Structuring International Governance through the Space of Concerns

When institutions decide by consensus, the official record shows agreement but hides who shaped what was decided. We introduce a way to recover that hidden structure from the one trace consensus cannot suppress: the documentary record of what actors choose to work on. Adapting tools from economic complexity, we map a ``space of concerns'' in which issues lie close when the same actors repeatedly specialize in both -- turning a flat agenda into a measurable topology of attention. Across six decades of the Antarctic Treaty (6,591 documents, 66 actors), engagement is structured, local, and persistent, and the most specialized actors produce binding law at roughly five times the baseline rate. The approach generalizes to any document-rich consensus forum, showing that unanimity does not erase political structure -- it relocates it upstream, into the organization of attention.

cs.SI

The Paradox of Intervention: Resilience in Adaptive Multi-Role Coordination Networks

Complex adaptive networks exhibit remarkable resilience, driven by the dynamic interplay of structure (interactions) and function (state). While static-network analyses offer valuable insights, understanding how structure and function co-evolve under external interventions is critical for explaining system-level adaptation. Using a unique dataset of clandestine criminal networks, we combine empirical observations with computational modeling to test the impact of various interventions on network adaptation. Our analysis examines how networks with specialized roles adapt and form emergent structures to optimize cost-benefit trade-offs. We find that emergent sparsely connected networks exhibit greater resilience, revealing a security-efficiency trade-off. Notably, interventions can trigger a "criminal opacity amplification" effect, where criminal activity increases despite reduced network visibility. While node isolation fragments networks, it strengthens remaining active ties. In contrast, deactivating nodes (analogous to social reintegration) can unintentionally boost criminal coordination, increasing activity or connectivity. Failed interventions often lead to temporary functional surges before reverting to baseline. Surprisingly, stimulating connectivity destabilizes networks. Effective interventions require precise calibration to node roles, connection types, and external conditions. These findings challenge conventional assumptions about connectivity and intervention efficacy in complex adaptive systems across diverse domains.

physics.soc-ph

Three Myths in Complexity Science and How to Resolve Them

From bird flocking to neural dynamics, complex systems generate fascinating structures and correlations. Often, seemingly simple dynamics lead to intricate emergent properties. Despite their visceral appeal, defining complex systems lacks universal agreement. In this paper, I will debunk three prevalent myths in complex systems and propose resolutions. This work contributes by offering a contemporary interpretation of complex systems, presenting essential definitions that benefit complexity scientists.

physics.hist-ph

Cascades towards noise-induced transitions on networks revealed using information flows

Complex networks, from neuronal assemblies to social systems, can exhibit abrupt, system-wide transitions without external forcing. These endogenously generated ``noise-induced transitions'' emerge from the intricate interplay between network structure and local dynamics, yet their underlying mechanisms remain elusive. Our study unveils two critical roles that nodes play in catalyzing these transitions within dynamical networks governed by the Boltzmann-Gibbs distribution. We introduce the concept of ``initiator nodes'', which absorb and propagate short-lived fluctuations, temporarily destabilizing their neighbors. This process initiates a domino effect, where the stability of a node inversely correlates with the number of destabilized neighbors required to tip it. As the system approaches a tipping point, we identify ``stabilizer nodes'' that encode the system's long-term memory, ultimately reversing the domino effect and settling the network into a new stable attractor. Through targeted interventions, we demonstrate how these roles can be manipulated to either promote or inhibit systemic transitions. Our findings provide a novel framework for understanding and potentially controlling endogenously generated metastable behavior in complex networks. This approach opens new avenues for predicting and managing critical transitions in diverse fields, from neuroscience to social dynamics and beyond.

cs.SI

Criminal organizations exhibit hysteresis, resilience, and robustness by balancing security and efficiency

The interplay between criminal organizations and law enforcement disruption strategies is crucial in criminology. Criminal enterprises, like legitimate businesses, balance visibility and security to thrive. This study uses evolutionary game theory to analyze criminal networks' dynamics, resilience to interventions, and responses to external conditions. We find strong hysteresis effects, challenging traditional deterrence-focused strategies. Optimal thresholds for organization formation or dissolution are defined by these effects. Stricter punishment doesn't always deter organized crime linearly. Network structure, particularly link density and skill assortativity, significantly influences organization formation and stability. These insights advocate for adaptive policy-making and strategic law enforcement to effectively disrupt criminal networks.

physics.soc-ph

The dynamic importance of nodes is poorly predicted by static network features

One of the most central questions in network science is: which nodes are most important? Often this question is answered using structural properties such as high connectedness or centrality in the network. However, static structural connectedness does not necessarily translate to dynamical importance. To demonstrate this, we simulate the kinetic Ising spin model on generated networks and one real-world weighted network. The dynamic impact of nodes is assessed by causally intervening on node state probabilities and measuring the effect on the systemic dynamics. The results show that structural features such as network centrality or connectedness are actually poor predictors of the dynamical impact of a node on the rest of the network. A solution is offered in the form of an information theoretical measure named integrated mutual information. The metric is able to accurately predict the dynamically most important node ('driver' node) in networks based on observational data of non-intervened dynamics. We conclude that the driver node(s) in networks are not necessarily the most well-connected or central nodes. Indeed, the common assumption of network structural features being proportional to dynamical importance is false. Consequently, great care should be taken when deriving dynamical importance from network data alone. These results highlight the need for novel inference methods that take both structure and dynamics into account.

physics.soc-ph