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OCEANS MTS/IEEE Monterey (Conference)

作者： Izaskun Garrido Aitor J. Garrido Jon Lekube Erlantz Otaola Edorta Carrascal Automatic Control Group Department of Automatic Control and Systems Engineering EUITI de Bilbao University of the Basque Country Automatic Control Group - ACG. Inst. of Research and Development of Processes Dept. Aut. Control and Systems Eng. University of the Basque Country (UPV/EHU)

ISBN: (纸本)9781509015276

This article covers research into cost reduction pathways for wave energy. The primary focus is the development and test of reliable and controllable power take-off (PTO) technology for oscillating water column converters (OWC). This is highly relevant to the ocean energy challenge. Extensive testing via data of the NEREIDA MOWC demonstration project, a breakwater wave plant located in the Basque location of Mutriku, using Wells turbines and Doubly Fed Induction (DFIG) generators is proposed to advance wave energy converter (WEC) devices. The control tests involve the integration of the PTO technology within a new variable controller for OWC wave power generation plants. Due to the nature of the control law, it allows monitoring faults caused by parametrical errors or system disturbances. The reliability tests by means of analysing the electrical signals have been conceived as conditioning monitoring, detection of mechanical faults and hardware damaging also fulfil a secondary aim for the reduction of maintenance cost and unscheduled downtime during operation of OWC plants.

关键词： Modelling and Simulation control Wave Energy OWC Condition Monitoring

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Constrained deterministic leader-follower mean field control

Constrained deterministic leader-follower mean field control

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American control Conference

作者： Lukas Moller Basilio Gentile Francesca Parise Sergio Grammatico John Lygeros Automatic Control Laboratory ETH Zurich Switzerland Control Systems group Deptartment of Electrical Engineering Eindhoven University of Technology The Netherlands

ISBN: (纸本)9781467386838

We consider a mean field game among a large population of noncooperative agents divided into two categories: leaders and followers. Each agent is subject to heterogeneous convex constraints and minimizes a quadratic cost function;the cost of each leader is affected by the leaders' aggregate strategy, while the cost of each follower is affected by both the leaders' and followers' aggregate strategy. We propose a decentralized scheme in which the agents update their strategies optimally with respect to a global incentive signal, possibly different for leaders and followers, broadcast by a central coordinator. We propose several incentive update rules that, under different conditions on the problem data, are guaranteed to steer the population to an ε-Nash equilibrium, with ε decreasing linearly to zero as the number of players increases. We illustrate our theoretical results on a demand-response program between electricity consumers and producers in the day-ahead market.

关键词： Sociology Statistics Noise measurement Games Aggregates Cost function Nash equilibrium Noise measurement Cost functions Nash equilibrium Sociology Leaders aggregates Game theory field control Leadership Agents

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Target-distractor synchrony affects performance in a novel motor task for studying action selection

arXiv

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arXiv 2017年

作者： James, Sebastian Bell, Olivia A. Nazli, Muhammed A.M. Pearce, Rachel E. Spencer, Jonathan Tyrrell, Katie Paine, Phillip J. Heaton, Timothy J. Anderson, Sean Lio, Mauro Da Gurney, Kevin Adaptive Behaviour Research Group Department of Psychology University of Sheffield Sheffield United Kingdom Insigneo Institute for in-silico Medicine University of Sheffield Sheffield United Kingdom Department of Automatic Control Systems Engineering University of Sheffield Sheffield United Kingdom Department of Industrial Engineering Università degli Studi di Trento Trento Italy School of Mathematics and Statistics University of Sheffield Sheffield United Kingdom

The study of action selection in humans can present challenges of task design since our actions are usually defined by many degrees of freedom and therefore occupy a large action-space. While saccadic eye-movement offers a more constrained paradigm for investigating action selection, the study of reach-and-grasp in upper limbs has often been defined by more complex scenarios, not easily interpretable in terms of such selection. Here we present a novel motor behaviour task which addresses this by limiting the action space to a single degree of freedom in which subjects have to track (using a stylus) a vertical coloured target line displayed on a tablet computer, whilst ignoring a similarly oriented distractor line in a different colour. We ran this task with 55 subjects and showed that, in agreement with previous studies, the presence of the distractor generally increases the movement latency and directional error rate. Further, we used two distractor conditions according to whether the distractor’s location changes asynchronously or synchronously with the location of the target. We found that the asynchronous distractor yielded poorer performance than its synchronous counterpart, with significantly higher movement latencies and higher error rates. We interpret these results in an action selection framework with two actions (move left or right) and competing ‘action requests’ offered by the target and distractor. As such, the results provide insights into action selection performance in humans and supply data for directly constraining future computational models therein. Copyright © 2017, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

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Amidst centralized and distributed frequency control in power systems

Amidst centralized and distributed frequency control in powe...

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American control Conference

作者： Florian Dorfler Sergio Grammatico Automatic Control Laboratory ETH Zurich Switzerland Control Systems group Dep. of Electrical Engineering Eindhoven University of Technology The Netherlands

ISBN: (纸本)9781467386838

We propose a novel frequency control approach in between centralized and distributed architectures, that is a generalized continuous-time feedback control version of the dual decomposition optimization method. Specifically, a convex combination of the frequency measurements is centrally aggregated and followed by an integral control, which is broadcast as the control signal, and then by the optimal local allocations. We show that our controller comprises many previously proposed strategies for specific parameter sets. Under mild parametric assumptions, we prove local asymptotic stability of the closed-loop equilibria of the power system, which is modeled as a nonlinear, differential-algebraic, dynamical system that includes traditional generators, frequency-responsive as well as passive loads, where the sources are already equipped with primary droop control. Our feedback control is designed such that the closed-loop equilibria of the power system solve the optimal economic dispatch problem.

关键词： Atmospheric measurements Particle measurements Particle measurements power systems atmospheric monitoring Frequency control frequency measurement feedback control integral control asymptotic stability region

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OWC on-shore wave power plants modeling and simulation

OWC on-shore wave power plants modeling and simulation

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IEEE International Conference on Emerging Technologies and Innovative Business Practices for the Transformation of Societies (EmergiTech)

作者： A.J. Garrido I. Garrido J. Lekube M. de la Sen E. Carrascal Automatic Control Group Department of Automatic Control and Systems Engineering University of the Basque Country (UPV/EHU) Bilbao Spain Dept. Aut. Control and Systems Eng. University of the Basque Country (UPV/EHU) Bilbao Spain Department of Electricity and Electronics University of the Basque Country (UPV/EHU) Spain Automatic Control Group - ACG University of the Basque Country (UPV/EHU) Spain

ISBN: (纸本)9781509007073

The Spanish Renewable Energies Plan (SREP) for 2011-2020 and the European Energy Road Map are promoting the use of renewable sources as the best way to avoid the undesired global warming, and in particular, the use of Ocean Energy. Within the different types of on-shore wave-based ocean energy devices, Oscillating Water Column (OWC) converters are one of the widely used ones. An OWC device is basically composed by a capture chamber with a turbo-generator module attached to it. This paper presents the modeling and simulation of OWC on-shore wave power plants. The results are particularised for the case of the Mutriku's power plant and then validated by means of experimental data.

关键词： Turbines Mathematical model Conferences Business Torque Data models

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Analysis of 3D plasma motions in a chromospheric jet formed due to magnetic reconnection

arXiv

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arXiv 2018年

作者： González-Avilés, J.J. Guzmán, F.S. Fedun, V. Verth, G. Sharma, R. Shelyag, S. Regnier, S. Instituto de Geofísica Unidad Michoacán Universidad Nacional Autónoma de México Antigua Carretera a Pátzcuaro Morelia Michoacán8710 Mexico Laboratorio de Inteligencia Artificial y Supercómputo Instituto de Física y Matemáticas UniversidadMichoacana de San Nicolás de Hidalgo Edificio C3 Cd. Universitaria Morelia Michoacán5840 Mexico Department of Automatic Control and Systems Engineering University of Sheffield Mappin Street SheffieldS1 3JD United Kingdom School of Mathematics and Statistics University of Sheffield Hicks Building Hounsfield Road SheffieldS3 7RH United Kingdom Space Research Group - Space Weather Departamento de Física y Matemáticas Universidad de Alcalá Calle el Escorial 19-21 Alcalá de28805 Department of Mathematics Physics and Electrical Engineering Northumbria University Ellison Place Newcastle upon TyneNE1 8ST United Kingdom

Within the framework of resistive MHD, implementing the C7 equilibrium atmosphere model and a 3D potential magnetic field realistic configuration, we simulate the formation of a plasm jet with the morphology, upward velocity up to 130 km/s and timescale formation between 60 and 90 s after beginning of simulation, similar to those expected for Type II spicules. Initial results of this simulation were published in Paper (e.g., González-Avilés et al. 2018) and present paper is devoted to the analysis of transverse displacements and rotational type motion of the jet. Our results suggest that 3D magnetic reconnection may be responsible for the formation of the jet in Paper (González-Avilés et al. 2018). In this paper, by calculating times series of the velocity components vx and vy in different points near to the jet for various heights we find transverse oscillations in agreement with spicule observations. We also obtain a time-distance plot of the temperature in a cross-cut at the plane x =0.1 Mm and find significant transverse displacements of the jet. By analyzing temperature isosurfaces of 104 K with the distribution of vx, we find that if the line-of-sight (LOS) is approximately perpendicular to the jet axis then there is both motion towards and away from the observer across the width of the jet. This red-blue shift pattern of the jet is caused by rotational motion, initially clockwise and anti-clockwise afterwards, which could be interpreted as torsional motion. From a nearly vertical perspective of the jet the LOS velocity component shows a central blue-shift region surrounded by red-shifted plasma. Copyright © 2018, The Authors. All rights reserved.

关键词： Magnetohydrodynamics

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Robust Event-Triggered MPC for Constrained Linear Discrete-Time systems with Guaranteed Average Sampling Rate

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IFAC-PapersOnLine 2015年第23期48卷 117-122页

作者： Brunner, Florian D. Heemels, W.P.M.H. Allgöwer, Frank Institute for Systems Theory and Automatic Control University of Stuttgart Pfaffenwaldring 9 Stuttgart70569 Germany Control System Technology Group Department of Mechanical Engineering Eindhoven University of Technology Netherlands

We propose a robust event-triggered model predictive control (MPC) scheme for linear time-invariant discrete-time systems subject to bounded additive stochastic disturbances and hard constraints on the input and state. For given probability distributions of the disturbances acting on the system, we design event conditions such that the average frequency of communication between the controller and the actuator in the closed-loop system attains a given value. We employ Tube MPC methods to guarantee robust constraint satisfaction and a robust asymptotic bound on the system state. Moreover, we show that based on a given periodically updated Tube MPC scheme, an appropriate event-triggered MPC scheme can be designed, with the same guarantees on constraints and region of attraction, but with a reduced number of average communications. © 2015, IFAC (International Federation of automatic control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Discrete time control systems Closed loop systems Digital control systems Linear control systems Model predictive control Predictive control systems Probability distributions Robustness (control systems) Stochastic models Stochastic systems Constraint Satisfaction Discrete time systems Event triggered controls Linear discrete time systems Linear time invariant Predictive control Region of attraction Stochastic disturbances

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Sparse Bayesian Identification of Polynomial NARX Models

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IFAC-PapersOnLine 2015年第28期48卷 172-177页

作者： Jacobs, William R. Baldacchino, Tara Anderson, Sean R. Department of Automatic Control and Systems Engineering University of Shefield Shefield United Kingdom Dynamics Research Group Department of Mechanical Engineering University of Shefield Dynamics Research Group Department of Mechanical Engineering University of Shefield Shefield United Kingdom

In this paper a novel sparse Bayesian structure detection algorithm is introduced for the identification of nonlinear autoregressive with exogenous inputs (NARX) dynamic systems. The main advantage of this algorithm over alternatives is that parameter uncertainty is naturally incorporated, and parameter estimation by variational inference is computationally efficient, consisting of a sequence of closed form updates. The proposed framework is demonstrated through a commonly used simulated benchmark problem. © 2015

关键词： Inference engines Identification (control systems) automatic relevance determination Bench mark problems Computationally efficient NARX models Non linear autoregressive with exogenous Parameter uncertainty Variational bayes Variational inference

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Predicting Risk of Suicide Using Resting State Heart Rate

Predicting Risk of Suicide Using Resting State Heart Rate

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Asia-Pacific Signal and Information Processing Association Annual Summit and Conference

作者： Daud Sikander Mahnaz Arvaneh Francesco Amico Graham Healy Tomas Ward Damien Kearney Eva Mohedano Jennifer Fagan John Yek Alan F. Smeaton Justin Brophy Automatic Control and Systems Engineering Department University of Sheffield Sheffield United Kingdom Newcastle Hospital Co. Wicklow Ireland The Insight Centre for Data Analytics Dublin City University Ireland Biomedical Engineering Research Group Maynooth University Ireland

ISBN: (纸本)9781509024018

This study investigates the potential of using heart rate-related measurements to aid clinicians in predicting suicide risk. For this purpose, heart rate was recorded during 10 minutes resting state from 15 patients with suicide ideation and 15 healthy subjects using an affordable and wearable sensor. Our results showed statistically significant differences (p<0.05) in two time-domain features measuring overall heart rate variability and short term heart rate variations. KNN and SVM classifiers were implemented on the features obtained. Our results showed that using heart rate-related features the risk of suicide could be predicted by an average accuracy of 80%.

关键词： Predicting Risk Suicide Resting State Heart Rate

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Magnetic swirls and associated fast magnetoacoustic kink waves in a solar chromospheric flux tube

arXiv

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arXiv 2017年

作者： Murawski, K. Kayshap, P. Srivastava, A.K. Pascoe, D.J. Jelínek, P. Kuźma, B. Fedun, V. Maria Curie-Sklodowska University Institute of Physics Group of Astrophysics Radziszewskiego 10 LublinPL–20 031 Poland Centre for Fusion Space and Astrophysics Department of Physics University of Warwick CV4 7AL United Kingdom Department of Physics Indian Institute of Technology Banaras Hindu University Varanasi221005 India University of South Bohemia Faculty of Science Institute of Physics and Biophysics Branišovská 1760 České BudějoviceCZ – 370 05 Czech Republic Space Systems Laboratory Department of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom

We perform numerical simulations of impulsively generated magnetic swirls in an isolated flux tube which is rooted in the solar photosphere. These swirls are triggered by an initial pulse in a horizontal component of the velocity. The initial pulse is launched either: (a) centrally, within the localized magnetic flux tube;or (b) off-central, in the ambient medium. The evolution and dynamics of the flux tube is described by three-dimensional, ideal magnetohydrodynamic equations. These equations are numerically solved to reveal that in case (a) dipole-like swirls associated with the fast magnetoacoustic kink and m = 1 Alfvén waves are generated. In case (b), the fast magnetoacoustic kink and m = 0 Alfvén modes are excited. In both these cases, the excited fast magnetoacoustic kink and Alfvén waves consist of similar flow pattern and magnetic shells are also generated with clockwise and counter-clockwise rotating plasma within them, which can be the proxy of dipole-shaped chromospheric swirls. The complex dynamics of vortices and wave perturbations reveals the channelling of sufficient amount of energy to fulfill energy losses in the chromosphere (∼ 104 W m−1) and in the corona (∼ 102 W m−1). Some of these numerical findings are reminiscent of signatures in recent observational data. Copyright © 2017, The Authors. All rights reserved.

关键词： Magnetic flux

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