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Modelling 3D magnetic networks in a realistic solar atmosphere

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arXiv 2019年

作者： Gent, Frederick A. Snow, Ben Fedun, Viktor Erdélyi, Robertus Academy of Finland ReSoLVE Centre of Excellence Department of Computer Science Aalto University FI-02150 Finland College of Engineering Mathematics and Physical Sciences University of Exeter EX4 4QF United Kingdom School of Mathematics Statistics and Physics Newcastle University NE1 7RU United Kingdom School of Mathematics and Statistics University of Sheffield S3 7RH United Kingdom Plasma Dynamics Group Department of Automatic Control and Systems Engineering University of Sheffield S1 3JD United Kingdom Department of Astronomy Eötvös Loránd University Pázmány Péter sétány 1/A Budapest H-1117 Hungary

The magnetic network extending from the photosphere (solar radius ' R) to lower corona (R + 10 Mm) plays an important role in the heating mechanisms of the solar atmosphere. Here we further develop the models with realistic open magnetic flux tubes of the authors in order to model more complicated configurations. Closed magnetic loops, and combinations of closed and open magnetic flux tubes are modelled. These are embedded within a stratified atmosphere, derived from observationally motivated semi-empirical and data-driven models subject to solar gravity and capable of spanning from the photosphere up into the chromosphere and lower corona. Constructing a magnetic field comprising self-similar magnetic flux tubes, an analytic solution for the kinetic pressure and plasma density is derived. Combining flux tubes of opposite polarity it is possible to create a steady background magnetic field configuration modelling a solar atmosphere exhibiting realistic stratification. The result can be applied to SOHO/MDI and SDO/HMI and other magnetograms from the solar surface, upon which photospheric motions can be simulated to explore the mechanism of energy transport. We demonstrate this powerful and versatile method with an application to Helioseismic and Magnetic Imager data. Copyright © 2019, The Authors. All rights reserved.

关键词： 3D modeling

Development and test verification of air temperature model for Chinese solar and Spainish Almeria-type greenhouses

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International Journal of Agricultural and Biological engineering 2017年第4期10卷 66-76页

作者： Jorge Antonio Sanchez-Molina Li Ming Francisco Rodriguez Jose Luis Guzman Wang Hui Yang Xinting The Automatic Control Robotics and Mechatronics Research GroupDepartment of InformaticsceiA3CIESOLUniversity of AlmeriaAlmeria 04120Spain Beijing Research Center for Information Technology in Agriculture/National Engineering Research Center for Information Technology in Agriculture/National Engineering Laboratory for Agri-product Quality Traceability/Key Laboratory for Information Technologies in Agriculture Ministry of AgricultureBeijing 100097China

Growth can be defined as an increment in biomass or an increment in weight or height of the organs of the plant influenced by physiological *** of these processes have their limits genetically determined,but climate and irrigation play an important *** of its importance,microclimate has been extensively studied in the modeling as a surrounding condition which is imposed by the exterior *** main objective of this work was to develop a temperature model based on the energy balance dynamics at two different greenhouse locations-South-eastern Spain and Northern China,and the traditional structures of Chinese solar greenhouse and Almería-type multi-span greenhouse were taken into *** final model was developed by combining the external conditions,the actuator influence and the crop growth,where the temperature is influenced by soil,crop,cover,actuators,back wall and greenhouse *** model took into account the energy lost by convective and conductive fluxes,as well as the energy supplied by solar radiation and heating *** soil and the back wall are the main media for energy *** temperature dynamic was determined by a physical model,which considered the energy balance from a holistic point of view-as a sub-model for a customizable interface among the external climate,the plant and the greenhouse *** influences of different subsystems included in the temperature model were analyzed and *** results showed a high R^(2)value of 0.94 for Beijing and 0.95 for Almeria,and the average error was low,of which the MAE and RMSE were 0.71 and 1.365 for Almeria and 0.62 and 1.102 for Beijing,***,the model can be considered as a powerful tool for control design purposes in microclimate systems.

关键词： air temperature model Chinese solar greenhouse Spanish Almería-type greenhouse energy balance dynamics microclimate

Numerical Evaluation of a Robust Self-Triggered MPC Algorithm

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IFAC-PapersOnLine 2016年第22期49卷 151-156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 present numerical examples demonstrating the efficacy of a recently proposed self-triggered model predictive control scheme for disturbed linear discrete-time systems with hard constraints on the input and state. In order to reduce the amount of communication between the controller and the actuator, the control input is not re-computed at each point in time but only at certain sampling instances. These instances are determined in a self-triggered fashion in the sense that at every sampling instant the next sampling instant is computed as a function of the current system state. A compact set in the state space, whose size is a design parameter in the control scheme, is stabilized. © 2016

关键词： Discrete time control systems Digital control systems Model predictive control Predictive control systems Robustness (control systems) control inputs control schemes Design parameters Hard constraints Linear discrete time systems Predictive control Sampling instants Self triggered controls

Collaborative target-tracking control using multiple autonomous fixed-wing UAVs with constant speeds: Theory and experiments

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arXiv 2018年

作者： Sun, Zhiyong Garcia de Marina, Héctor Seyboth, Georg S. Anderson, Brian D.O. Yu, Changbin Research School of Engineering Australian National University CanberraACT2601 Australia Hangzhou310018 China Department of Automatic Control Lund University Lund Sweden Unmanned Aerial Systems centre Maersk Mc-Kinney Moller Institute University of Southern Denmark Odense MDK-5230 Denmark Robert Bosch Automotive Steering GmbH

—This paper considers a collaborative tracking control problem using a group of fixed-wing UAVs with constant and non-identical speeds. The dynamics of fixed-wing UAVs are modelled by unicycle-type equations, with nonholonomic constraints by assuming that UAVs fly at constant attitudes in the nominal operation mode. The control focus is on the design of a collective tracking controller such that all fixed-wing UAVs as a group can collaboratively track a desired target’s position and velocity. We construct a reference velocity that includes both the target’s velocity and position as feedback, which is to be tracked by the group centroid. In this way, all vehicles’ headings are controlled such that the group centroid follows a reference trajectory that successfully tracks the target’s trajectory. We consider three cases of reference velocity tracking: the constant velocity case, the turning velocity case with constant speed, and the time-varying velocity case. An additive spacing controller is further devised to ensure that all vehicles stay close to the group centroid trajectory. Trade-offs and performance limitations of the target tracking control due to the constant-speed constraint are also discussed in detail. Experimental results with three fixed-wing UAVs tracking a target rotorcraft are shown to validate the effectiveness and performance of the proposed tracking controllers. Copyright © 2018, The Authors. All rights reserved.

关键词： Fixed wings

Iterative information granulation for novelty detection in complex datasets

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Iterative information granulation for novelty detection in c...

2016 IEEE International Conference on Fuzzy systems, FUZZ-IEEE 2016

作者： Adrian, Rubio-Solis Panoutsos, George Automatic Control and Systems Engineering Department University of Sheffield United Kingdom

ISBN: (纸本)9781509006250

Recognition memory in a number of mammals is usually utilised to identify novel objects that violate model predictions. In humans in particular, the recognition of novel objects is foremost associated to their ability to group objects that are highly compatible/similar. Granular computing not only mimics the human cognition to draw objects together but also mimics the ability to capture associated properties by similarity, proximity or functionality. In this paper, an iterative information granulation approach is presented, for the problem of novelty detection in complex data. Two granular compatibility measures are used, based on principles of Granular Computing, namely the multidimensional distance between the granules, as well as the granular density and volume. A two-stage iterative information granulation is proposed in this work. In the first stage, a predefined number of granular detectors are constructed. The granular detectors capture the relationships (rules) between the inputoutput data and then use this information in a second granulation stage in order to discriminate new samples as novel. The proposed iterative information granulation approach for novelty detection is then applied to three different benchmark problems in pattern recognition demonstrating very good performance. © 2016 IEEE.

关键词： Granular computing

Frequency-driven market mechanisms for optimal dispatch in power networks

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arXiv 2017年

作者： Stegink, Tjerk Cherukuri, Ashish de Persis, Claudio van der Schaft, Arjan Cortés, Jorge Center for Systems and Control University of Groningen Netherlands Automatic Control Laboratory ETH Zürich Department of Mechanical and Aerospace Engineering University of California San Diego United States

This paper studies real-time bidding mechanisms for economic dispatch and frequency regulation in electrical power networks. We consider a market administered by an independent system operator (ISO) where a group of strategic generators participate in a Bertrand game of competition. Generators bid prices at which they are willing to produce electricity. Each generator aims to maximize their profit, while the ISO seeks to minimize the total generation cost and to regulate the frequency of the system. We consider a continuous-time bidding process coupled with the swing dynamics of the network through the use of frequency as a feedback signal for the negotiation process. We analyze the stability of the resulting interconnected system, establishing frequency regulation and the convergence to a Nash equilibrium and optimal generation levels. The results are verified in the IEEE 14-bus benchmark case. Copyright © 2017, The Authors. All rights reserved.

关键词： Electric load dispatching

Model fitting and simulation of the respiratory control system under incremental exercise and altitude in healthy subjects 7th

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Model fitting and simulation of the respiratory control syst...

7th Latin American Congress on Biomedical engineering, CLAIB 2016

作者： Sarmiento, C.A. Hernández, A.M. Serna, L.Y. Bioinstrumentation and Clinical Engineering Research Group - GIBIC Bioengineering Department Engineering Faculty Universidad de Antioquia UdeA Calle 70 No. 52-21 Medellín Colombia Department of Automatic Control ESAII Biomedical Engineering Research Center CREB Technical University of Catalonia Barcelona Spain Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine CIBER-BBN Barcelona Spain

ISBN: (纸本)9789811040856

The modeling and simulation of the respiratory control system allows a better understanding of the physiological system to different stimuli and pathologies. Although different models have been validated under different situations, it is unusual to perform a fitting of their parameters based on environmental characteristics such as altitude, which can significantly affect the accuracy of the simulation results. The purpose of this work is to fit the respiratory control model proposed by Fincham and Tehrani with experimental data obtained under exercise. The experimental test include carbon dioxide production between 0.4 and 2.5 l / min at an altitude of 1538 m above sea level. The variables compared between simulation without fitting and with fitting regarding experimental data were total minute ventilation, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide and Frequency of breathing. The results evidence the altitude as a stimulus that should be considered in simulations of respiratory models in order to obtain more accurate results. © Springer Nature Singapore Pte Ltd. 2017.

关键词： Carbon dioxide

Overview of groups forming methods for long student's project

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Overview of groups forming methods for long student's projec...

Strategic Partnership of Universities and Enterprises of Hi-Tech Branches (Science. Education. Innovations), IV Forum

作者： T. A. Minav Anastasia D. Stotskaya Department of Mechanical Engineering Aalto University Aalto Finland Department of Automatic Control Systems Saint Petersburg Electrotechnical University “1” St. Petersburg Russia

ISBN: (纸本)9781538625729

Lecturing is one of the most traditional methods for teaching in university which can be lacking of interaction and real life application. This is a reason to transition to small groups with objectives of project development are appearing in the end of many master thesis programs. These project-based courses are created for better prepare student engineers for engineering work practices. Starting from 1990s, project-based courses has become a regular part of most undergraduate engineering programs. In these courses, small groups provide opportunity for students to engage actively with learning, to enhance practical skills, and to develop 21 century skills such as critical thinking, oral communication, and collaboration. Consequently, all academic staff involved in supporting and supervising group-based student projects sometimes face problems in forming effective groups. This becomes even more difficult when the life of the group project spans between 2 to 10 months. Therefore, this research paper concentrates on reviewing methods for the formation of groups of students working in such lengthy projects in order to create guidance, which will help instructors to divide students into groups, and organize and coordinate the work dynamic among team members.

关键词： Education Mechanical engineering Oral communication Face Teamwork

Weak interactions based system partitioning using integer linear programming

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arXiv 2017年

作者： Guicherd, Romain Trodden, Paul A. Mills, Andrew R. Kadirkamanathan, Visakan Rolls-Royce University Technology Centre Department of Automatic Control & Systems Engineering University of Sheffield Mappin Street SheffieldS1 3JD United Kingdom

The partitioning of a system model will condition the structure of the controller as well as its design. In order to partition a system model, one has to know what states and inputs to group together to define subsystem models. For a given partitioning, the total magnitude of the interactions between subsystem models is evaluated. Therefore, the partitioning problem seeking for weak interactions can be posed as a minimization problem. Initially, the problem is formulated as a non-linear integer minimization that is then relaxed into a linear integer programming problem. It is shown within this paper that cuts can be applied to the initial search space in order to find the least interacting partitioning;only composed of controllable subsystems. Two examples are given to demonstrate the methodology. Copyright © 2017, The Authors. All rights reserved.

关键词： Integer programming