In this article we consider the 𝛾-stabilization of nth-order linear time-invariant dynamical systems using multiplicity-induced-dominancy-based controller design in the presence of delays in the input or the output channels. A sufficient condition is given for the dominancy of a real root with multiplicity at least n + 1 and at least n using an integral factorization of the corresponding characteristic function. A necessary condition for 𝛾-stabilizability is analyzed utilizing the property that the derivative of a 𝛾-stable quasipolynomial is also 𝛾-stable under certain conditions. Sufficient and necessary conditions are given for systems with real-rooted open-loop characteristic function: the delay intervals are determined where the conditions for dominancy and 𝛾-stabilizability are satisfied. The efficiency of the proposed controller design is shown in the case of a multilink inverted pendulum. K E Y W O R D Scharacteristic equation, dominant roots, feedback system, stabilizability, time delay INTRODUCTIONStabilization of unstable equilibria and orbits in the presence of communication delay is an important and challenging task in engineering applications. [1][2][3] Finding the control parameters that allow stable operation for large feedback delay is not a trivial task. 4 Stability diagrams can be used to visualize stability properties in the space of control parameters. [5][6][7] When performance with respect to settling time has to be optimized in linear time-invariant systems then one has to deal Abbreviations: LTI, linear time-invariant; MID, multiplicity-induced-dominancyThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
The Internet of Things (IoT) is transforming the surrounding everyday physical objects into an ecosystem of information that enriches our everyday life. The IoT represents the convergence of advances in miniaturization, wireless connectivity, and increased data storage and is driven by various sensors. Sensors detect and measure changes in position, temperature, light, and many others; furthermore, they are necessary to turn billions of objects into data-generating “things” that can report on their status and often interact with their environment. Application and service development methods and frameworks are required to support the realization of solutions covering data collection, transmission, data processing, analysis, reporting, and advanced querying. This paper introduces the SensorHUB framework that utilizes the state-of-the-art open source technologies and provides a unified tool chain for IoT related application and service development. SensorHUB is both a method and an environment to support IoT related application and service development; furthermore, it supports the data monetization approach, that is, provides a method to define data views on top of different data sources and analyzed data. The framework is available in a Platform as a Service (PaaS) model and has been applied for the vehicle, health, production lines, and smart city domains.
The reliability of structural systems has to be verified against failure caused by extreme effects, such as fire and seismic effects. To the best of the authors' knowledge, there is a lack of studies in the literature on comprehensive reliability calculation of complex structural systems; the available studies mainly deal with the reliability calculation of simple, separated elements. In this study, a methodology is presented for the calculation of reliability of structures under fire exposure, giving a more complex and comprehensive basis for the calculation of structural reliability than earlier studies in the literature: a) the reliability calculation does not focuses on one single element but the whole structure; b) the presented methodology is able to consider any type of fire curve; c) reliability analysis includes the nonlinear analysis of the structure, in this way the highly nonlinear structural response is followed; d) the structural reliability is assessed on time basis. The applicability of the proposed algorithm is presented through reliability calculation of tapered portal frame structure protected by intumescent coating, as an example structure. The probability of failure is calculated using First Order Reliability Method. The resulted probabilities are verified using Monte Carlo Simulation.
Abstract:The application of buckling restrained braced frames is hindered in Europe by the absence of a standardized design procedure in Eurocode 8, the European seismic design standard. The presented research aims to develop a robust design procedure for buckling restrained braced frames. A design procedure is proposed by the authors. Its performance has been evaluated for buckling restrained braced frames with two-bay X-brace type brace configurations using a state-of-the-art methodology based on the recommendations in the FEMA P695 document. A special numerical material model was developed within the scope of this research to represent the behavior of buckling restrained braces more appropriately in a numerical environment. A total of 24 archetype designs were prepared and their nonlinear dynamic response was calculated using real ground motion records in incremental dynamic analyses. Evaluation of archetype collapse probabilities confirms that the proposed design procedure can utilize the advantageous behavior of buckling restrained braces. Resulting reliability indices suggest a need for additional regulations in the Eurocodes that introduce reasonable structural reliability index limits for seismic design.
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