Changes in Complex Adaptive Systems: The Role of External Influences

Dear Colleagues,

The scientific background of this Special Issue lies in examining the processes within complex systems that are capable of change, such as adaptation and learning, particularly in response to external influences, disturbances, noise, perturbations, and even deliberate external interventions. Since complexity is intrinsically linked to the occurrence of emergence processes, understood as the acquisition of properties such as coherence and correlations in collective behaviors and ecosystems, it is a matter of identifying approaches capable of influencing it to the point—in extreme cases—of inducing or even deactivating it. This applies to all types of complex systems, including biological, economic, medical, physical, and social systems.

Changes in environmental conditions, such as energy and constraint configurations, are examples of influences. The creative role of noise and errors in complex systems is well established, as in [1–3].

Among these influences, we highlight the role of three factors that are often overlooked: weak forces, remote synchronization, and network interactions between links in underlying networks.

• Weak forces:

We consider the inherent incompatibility between complexity and reductionist or mechanistic paradigms, which are often assumed to be comprehensive and sufficient for determining changes within a complex system. The focus should instead be on introducing appropriately modified constraints such as weak forces as inputs for the system to process, particularly through adaptive mechanisms [4]. This involves interdisciplinary approaches.

In generic networked systems, such as collective behaviors and social systems, we may consider the following:

• Remote synchronization:

At its most fundamental level, remote synchronization occurs when two nodes become synchronized even in the absence of a direct structural link between them. This sustained synchronization is mediated by intermediary nodes or by the broader network, which itself may remain unsynchronized [5,6].

• Networks of links between links:

Links within networks can themselves be considered nodes of a superimposed network, defining interlink interdependencies, relationships, compatibilities and incompatibilities, and the admissibility of link configurations [8]. Actions and interventions on these networks of links between links exert only weak-force-like effects [7].

Other aspects considerable for various types of systems include, for example, the following:

• Mesoscopicity: The mesoscopic level of description focuses on the ongoing interactions and negotiations between the micro and macro scales of complex systems [8] as for clusters with macroscopic properties but identified by micro characteristics, such as markets.
• Internal emergences: Processes of self-influence that may appear external but are actually self-generated should also be considered, as in ecosystems.
• Constraints: Phenomenological emergence cannot be explicitly dictated, but can only be induced. It remains highly sensitive to environmental constraints, relying on initial conditions, necessary adjustments, component configurations and topologies as in the case of vehicular traffic.
• Multiple systems: Interventions aimed at a single system often lead to corresponding changes in other interconnected systems, as seen in ecosystems. This interconnection creates mechanisms so that changes in one system can drive changes in another, as in social systems.

The purpose of this Special Issue is to explore approaches, cases, experiences, experiments, methodologies, models, pending issues, problems, simulations, and theoretical aspects related to, but not limited to, the above-mentioned interdisciplinary topics.

References

1. Agarwal, V.; Yorke, J.A.; Balachandran, B. Noise-induced chaotic-attractor escape route. Nonlinear Dyn2020, 102, 863–876. https://doi.org/10.1007/s11071-020-05873-3
2. Roli, A.; Braccini, M.; Stano, P. On the Positive Role of Noise and Error in Complex Systems. Systems 2024, 12, (9), 338 https://doi.org/10.3390/systems12090338
3. Jacob, R.; Harikrishnan, K.P.; Misra, R.; Ambika, G., How does noise affect the structure of a chaotic attractor: A recurrence network perspective, 2015 https://arxiv.org/abs/1508.02724
4. Minati, G. Multiplicity, Logical Openness, Incompleteness, and Quasi-ness as Peculiar Non-reductionist Properties of Complexity. In From Electrons to Elephants and Elections: Saga of Content and Context, Wuppuluri, S., Stewart, I., Eds.; Springer: New York, NY, USA, 2022; pp. 151–173 https://doi.org/10.1007/978-3-030-92192-7_10
5. Gambuzza, L.V.; Cardillo, A.; Fiasconaro, A.; Fortuna, L.; Gómez-Gardenes, J.; Frasca, M. Analysis of remote synchronization in complex networks. Chaos 2013, 23, 1–8.
6. Nicosia, V.; Valencia, M.; Chavez, M.; Diaz-Guilera, A.; Latora, V. Remote synchronization reveals network symmetries and functional modules. Physical Review Letters 2013, 110 (17), 174102–174106.
7. Minati, G., Linked Links-A Research Project: The Multiple Superimposed Soft Networks as Network Profiles. Systems2024, 12, (8), 303.  https://doi.org/10.3390/systems12080303
8. Minati, G.; Licata, I. Emergence as Mesoscopic Coherence, Systems 2013, 1, (4), 50-65. https://doi.org/10.3390/systems1040050

Dr. Gianfranco Minati
Dr. Andrea Roli
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Systems is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.