146 research outputs found

    Strong practical stability based robust stabilization of uncertain discrete linear repetitive processes

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    Repetitive processes are a distinct class of 2D systems of both theoretical and practical interest whose dynamics evolve over a subset of the positive quadrant in the 2D plane. The stability theory for these processes originally consisted of two distinct concepts termed asymptotic stability and stability along the pass respectively where the former is a necessary condition for the latter. Stability along the pass demands a bounded-input bounded-output property over the complete positive quadrant of the 2D plane and this is a very strong requirement, especially in terms of control law design. A more feasible alternative for some cases is strong practical stability, where previous work has formulated this property and obtained necessary and sufficient conditions for its existence together with Linear Matrix Inequality (LMI) based tests, which then extend to allow control law design. This paper develops considerably simpler, and hence computationally more efficient, stability tests that extend to allow control law design in the presence of uncertainty in process model

    Fruit trees and viruses: the molecular diagnosis.

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    Ten questions concerning energy flexibility in buildings

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    Funding Information: The authors are key collaborators in the IEA EBC Annex 82 project. Dr. Li leads IEA EBC Annex 82 “Energy Flexible Buildings Towards Resilient Low Carbon Energy Systems.” Mr. Satchwell researches utility regulatory and business models that achieve greater deployment of energy efficiency, demand flexibility, and other distributed energy resources. Prof. Finn investigates demand response measures in the residential and commercial building sectors. Senior researcher Christensen researches the role of users in smart energy solutions and low-carbon energy transitions. Prof. Michaël Kummert's research focuses on modeling and control of building-scale and community-scale energy systems to optimize energy flexibility and resilience. Dr. Le Dréau researches energy flexibility of buildings both at building and district scales, develops occupant behavior models and prediction techniques related to flexibility. Dr. Lopes is involved in two international projects funded by the European Union's H2020 programme where he is developing and applying energy flexibility characterization methodologies and optimization algorithms in several demonstration activities. Prof. Madsen leads a national research project ‘Energy Flexible Denmark’ and he focuses on grey-box modeling, digital twins, forecasting and control for smart buildings in smart grids. Dr. Salom research works focus on zero/positive energy buildings and districts and their interaction with energy infrastructures being involved in several international projects. Prof. Henze researches model predictive and reinforcement learning control and data analytics for the integration of building and district energy systems with the electric grid. Mr. Wittchen research works focus on zero/positive energy buildings and districts and implementation of European legislation on building's energy performance. Funding Information: The authors acknowledge the many organizations that directly or indirectly supported the completion of this article. We acknowledge the European Commission for the ARV (grant number 101036723 ), Syn.ikia (grant number 869918 ), Hestia (grant number 957823 ) projects; the Danish Energy Agency for supporting the Danish delegates participating IEA EBC Annex 82 through EUDP (grant number 64020-2131 ); Innovation Fund Denmark in relation to SEM4Cities ( IFD 0143–0004 ) and Flexible Energy Denmark ( IFD 8090-00069B ); the Building Technologies Office, Office of Energy Efficiency and Renewable Energy, at the US Department of Energy , under Lawrence Berkeley National Laboratory (contract number DE-AC02-05CH11231 ); the Center of Technology and Systems (CTS UNINOVA) and the Portuguese Foundation for Science and Technology (FCT) through the Strategic Program UIDB/00066/2020 ; Research Council of Norway in relation to Research Centre on Zero Emission Neighborhoods in Smart Cities - FME-ZEN (No. 2576609 ) and FlexBuild (No. 294920 ); the AGAUR Agency from the Generalitat de Catalunya through the project ComMit-20 ( 2020PANDE00116 ); the National Science and Engineering Research Council of Canada (NSERC Discovery Grant RGPIN 2016-06643 ). Publisher Copyright: © 2022 The AuthorsDemand side energy flexibility is increasingly being viewed as an essential enabler for the swift transition to a low-carbon energy system that displaces conventional fossil fuels with renewable energy sources while maintaining, if not improving, the operation of the energy system. Building energy flexibility may address several challenges facing energy systems and electricity consumers as society transitions to a low-carbon energy system characterized by distributed and intermittent energy resources. For example, by changing the timing and amount of building energy consumption through advanced building technologies, electricity demand and supply balance can be improved to enable greater integration of variable renewable energy. Although the benefits of utilizing energy flexibility from the built environment are generally recognized, solutions that reflect diversity in building stocks, customer behavior, and market rules and regulations need to be developed for successful implementation. In this paper, we pose and answer ten questions covering technological, social, commercial, and regulatory aspects to enable the utilization of energy flexibility of buildings in practice. In particular, we provide a critical overview of techniques and methods for quantifying and harnessing energy flexibility. We discuss the concepts of resilience and multi-carrier energy systems and their relation to energy flexibility. We argue the importance of balancing stakeholder engagement and technology deployment. Finally, we highlight the crucial roles of standardization, regulation, and policy in advancing the deployment of energy flexible buildings.publishersversionpublishe
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