Antifragility = Elasticity + Resilience + Machine Learning: Models and Algorithms for Open System Fidelity

We introduce a model of the fidelity of open systems - fidelity being interpreted here as the compliance between corresponding figures of interest in two separate but communicating domains. A special case of fidelity is given by real-timeliness and synchrony, in which the figure of interest is the physical and the system's notion of time. Our model covers two orthogonal aspects of fidelity, the first one focusing on a system's steady state and the second one capturing that system's dynamic and behavioural characteristics. We discuss how the two aspects correspond respectively to elasticity and resilience and we highlight each aspect's qualities and limitations. Finally we sketch the elements of a new model coupling both of the first model's aspects and complementing them with machine learning. Finally, a conjecture is put forward that the new model may represent a first step towards compositional criteria for antifragile systems.Comment: Preliminary version submitted to the 1st International Workshop "From Dependable to Resilient, from Resilient to Antifragile Ambients and Systems" (ANTIFRAGILE 2014), https://sites.google.com/site/resilience2antifragile

Design Margins: Impact on Building Energy Performance

This paper examines the addition of design margins for building services energy infrastructure during the design process. It argues that care must be taken when applying margins; ensuring cumulative effects do not undermine the ability of systems to be energy efficient. An example of a hospital Trust is provided showing the addition of design margins impacting the energy efficiency of services provided. Tensions are found between delivery of flexibility, adaptability and other change parameters and the need for the system to be bounded, so as to encourage effectiveness

Risk-Based Approach for Life-Cycle Assessment and Management of Bridges and Ship Structures

Existing civil and marine structures and infrastructures have to maintain their serviceability and safety under the effects induced by normal events and to withstand the effects of extreme events . Although the quantification of the performance of a structural system is usually conducted considering only structural aspects, in this study consequences arising from the occurrence of potential disruption of service due to failure/malfunction of structural components are also considered, leading to risk assessment.Uncertainties are unavoidable in planning, design, and maintenance of structural systems. Advanced probabilistic methods, such as Monte Carlo simulations based on Latin Hypercube sampling, finite element and response surfaces analyses are used in this study in order to account for uncertainties and their propagation over time.The main focus of this study is to develop a risk-based approach for the life-cycle assessment and management of civil and marine structures with emphasis on single highway bridges, groups of bridges, and ship structures. Risk is assessed for highway bridges under the effects of multiple hazards, including traffic, environmental attacks, scour, and earthquakes, whereas the effects of traffic and earthquake are accounted for groups of bridges. Other performance indicators, including reliability, redundancy, and resilience to disasters, are also investigated. For ship structures, a novel approach is developed for the evaluation of time-variant reliability, redundancy, and risk accounting for different limit states of the ship hull, potential effects induced by corrosion, and considering different ship operational conditions over time.Risk is assessed based on reliability analysis by accounting several limit states and quantifying the associated potential monetary losses for a spectrum of consequences, including operating costs and accident costs.A novel approach for near real-time multi-criteria optimal ship routing, integrating risk and structural health monitoring data is developed considering different damage scenarios and generic operational conditions.The developed approaches are applied to several structures, including a highway bridge crossing the Wisconsin River in Wausau, WI, a highway bridge carrying a segment of the northbound I-15 crossing the Temescal Wash located close to the city of Corona, CA, a group of existing bridges located north of the San Diego metropolitan area, and a NAVY\u27s Joint High-Speed Sealift

High-speed civil transport flight- and propulsion-control technological issues

Technology advances required in the flight and propulsion control system disciplines to develop a high speed civil transport (HSCT) are identified. The mission and requirements of the transport and major flight and propulsion control technology issues are discussed. Each issue is ranked and, for each issue, a plan for technology readiness is given. Certain features are unique and dominate control system design. These features include the high temperature environment, large flexible aircraft, control-configured empennage, minimizing control margins, and high availability and excellent maintainability. The failure to resolve most high-priority issues can prevent the transport from achieving its goals. The flow-time for hardware may require stimulus, since market forces may be insufficient to ensure timely production. Flight and propulsion control technology will contribute to takeoff gross weight reduction. Similar technology advances are necessary also to ensure flight safety for the transport. The certification basis of the HSCT must be negotiated between airplane manufacturers and government regulators. Efficient, quality design of the transport will require an integrated set of design tools that support the entire engineering design team

Computer trading and systemic risk: a nuclear perspective

Financial markets have evolved to become complex adaptive systems highly reliant on the communication speeds and processing power afforded by digital systems. Their failure could cause severe disruption to the provision of financial services and possibly the wider economy. In this study we consider whether a perspective from the nuclear industry can provide additional insights