@article{AxenieLopezCoronaMakridisetal.2024, author = {Axenie, Cristian and L{\´o}pez-Corona, Oliver and Makridis, Michail A. and Akbarzadeh, Meisam and Saveriano, Matteo and Stancu, Alexandru and West, Jeffrey}, title = {Antifragility in complex dynamical systems}, series = {npj Complexity}, volume = {1}, journal = {npj Complexity}, number = {1}, publisher = {Springer Science and Business Media LLC}, issn = {2731-8753}, doi = {10.1038/s44260-024-00014-y}, year = {2024}, abstract = {Antifragility characterizes the benefit of a dynamical system derived from the variability in environmental perturbations. Antifragility carries a precise definition that quantifies a system's output response to input variability. Systems may respond poorly to perturbations (fragile) or benefit from perturbations (antifragile). In this manuscript, we review a range of applications of antifragility theory in technical systems (e.g., traffic control, robotics) and natural systems (e.g., cancer therapy, antibiotics). While there is a broad overlap in methods used to quantify and apply antifragility across disciplines, there is a need for precisely defining the scales at which antifragility operates. Thus, we provide a brief general introduction to the properties of antifragility in applied systems and review relevant literature for both natural and technical systems' antifragility. We frame this review within three scales common to technical systems: intrinsic (input-output nonlinearity), inherited (extrinsic environmental signals), and induced (feedback control), with associated counterparts in biological systems: ecological (homogeneous systems), evolutionary (heterogeneous systems), and interventional (control). We use the common noun in designing systems that exhibit antifragile behavior across scales and guide the reader along the spectrum of fragility-adaptiveness-resilience-robustness-antifragility, the principles behind it, and its practical implications.}, language = {en} } @article{AxenieSaveriano2023, author = {Axenie, Cristian and Saveriano, Matteo}, title = {Antifragile Control Systems: The Case of Mobile Robot Trajectory Tracking Under Uncertainty and Volatility}, series = {IEEE Access}, volume = {11}, journal = {IEEE Access}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2169-3536}, doi = {10.1109/ACCESS.2023.3339988}, pages = {138188 -- 138200}, year = {2023}, abstract = {Mobile robots are ubiquitous. Such vehicles benefit from well-designed and calibrated control algorithms ensuring their task execution under precise uncertainty bounds. Yet, in tasks involving humans in the loop, such as elderly or mobility impaired, the problem takes a new dimension. In such cases, the system needs not only to compensate for uncertainty and volatility in its operation but at the same time to anticipate and offer responses that go beyond robust. Such robots operate in cluttered, complex environments, akin to human residences, and need to face during their operation sensor and, even, actuator faults, and still operate. This is where our thesis comes into the foreground. We propose a new control design framework based on the principles of antifragility. Such a design is meant to offer a high uncertainty anticipation given previous exposure to failures and faults, and exploit this anticipation capacity to provide performance beyond robust. In the current instantiation of antifragile control applied to mobile robot trajectory tracking, we provide controller design steps, the analysis of performance under parametrizable uncertainty and faults, as well as an extended comparative evaluation against state-of-the-art controllers. We believe in the potential antifragile control has in achieving closed-loop performance in the face of uncertainty and volatility by using its exposures to uncertainty to increase its capacity to anticipate and compensate for such events.}, language = {en} } @book{AxenieAkbarzadehMakridisetal.2025, author = {Axenie, Cristian and Akbarzadeh, Meisam and Makridis, Michail A. and Saveriano, Matteo and Stancu, Alexandru}, title = {Applied Antifragility in Technical Systems}, publisher = {Springer Nature Switzerland}, address = {Cham}, isbn = {9783031904240}, issn = {2191-5768}, doi = {10.1007/978-3-031-90425-7}, pages = {XVI, 122}, year = {2025}, abstract = {The book purpose is to build a foundational knowledge base by applying antifragile system design, analysis, and development in technical systems, with a focus on traffic engineering, robotics, and control engineering. The authors are interested in formalizing principles and an apparatus that turns the basic concept of antifragility into a tool for designing and building closed-loop technical systems that behave beyond robust in the face of uncertainty. As coined in the book of Nassim Taleb, antifragility is a property of a system to gain from uncertainty, randomness, and volatility, opposite to what fragility would incur. An antifragile system's response to external perturbations is beyond robust, such that small stressors can strengthen the future response of the system by adding a strong anticipation component. The work of the Applied Antifragility Group in traffic control and robotics, led by the authors, provides a good overview on the current research status.}, language = {en} }