%0 Journal Article %J PeerJ %D 2020 %T Ecosystem antifragility: beyond integrity and resilience %A Equihua, Miguel %A Espinosa Aldama, Mariana %A Gershenson, Carlos %A López-Corona, Oliver %A Munguía, Mariana %A Pérez-Maqueo, Octavio %A Ramírez-Carrillo, Elvia %K Antifragility %K Complexity %K Ecosystem integrity %K Resilience %X We review the concept of ecosystem resilience in its relation to ecosystem integrity from an information theory approach. We summarize the literature on the subject identifying three main narratives: ecosystem properties that enable them to be more resilient; ecosystem response to perturbations; and complexity. We also include original ideas with theoretical and quantitative developments with application examples. The main contribution is a new way to rethink resilience, that is mathematically formal and easy to evaluate heuristically in real-world applications: ecosystem antifragility. An ecosystem is antifragile if it benefits from environmental variability. Antifragility therefore goes beyond robustness or resilience because while resilient/robust systems are merely perturbation-resistant, antifragile structures not only withstand stress but also benefit from it. %B PeerJ %V 8 %P e8533 %G eng %U https://doi.org/10.7717/peerj.8533 %R 10.7717/peerj.8533 %0 Journal Article %J Peer-to-Peer Networking and Applications %D 2015 %T Measuring the complexity of adaptive peer-to-peer systems %A Amoretti, Michele %A Gershenson, Carlos %K Adaptive peer-to-peer system %K Complexity %K Evolution %K Information theory %X To improve the efficiency of peer-to-peer (P2P) systems while adapting to changing environmental conditions, static peer-to-peer protocols can be replaced by adaptive plans. The resulting systems are inherently complex, which makes their development and characterization a challenge for traditional methods. Here we propose the design and analysis of adaptive P2P systems using measures of complexity, emergence, self-organization, and homeostasis based on information theory. These measures allow the evaluation of adaptive P2P systems and thus can be used to guide their design. We evaluate the proposal with a P2P computing system provided with adaptation mechanisms. We show the evolution of the system with static and also changing workload, using different fitness functions. When the adaptive plan forces the system to converge to a predefined performance level, the nodes may result in highly unstable configurations, which correspond to a high variance in time of the measured complexity. Conversely, if the adaptive plan is less ``aggressive'', the system may be more stable, but the optimal performance may not be achieved. %B Peer-to-Peer Networking and Applications %P 1-16 %@ 1936-6442 %G eng %U http://dx.doi.org/10.1007/s12083-015-0385-4 %R 10.1007/s12083-015-0385-4 %0 Journal Article %J Complexity %D 2015 %T When slower is faster %A Gershenson, Carlos %A Helbing, Dirk %K cascading effects %K collective motion %K Evolution %K phase transitions %X The slower is faster (SIF) effect occurs when a system performs worse as its components try to do better. Thus, a moderate individual efficiency actually leads to a better systemic performance. The SIF effect takes place in a variety of phenomena. We review studies and examples of the SIF effect in pedestrian dynamics, vehicle traffic, traffic light control, logistics, public transport, social dynamics, ecological systems, and adaptation. Drawing on these examples, we generalize common features of the SIF effect and suggest possible future lines of research. {\copyright} 2015 Wiley Periodicals, Inc. Complexity 21: 9–15, 2015 %B Complexity %V 21 %P 9–15 %G eng %U http://arxiv.org/abs/1506.06796 %R 10.1002/cplx.21736