检索结果-内蒙古大学图书馆

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

来源：评论

学校读者我要写书评

暂无评论

Sparse Bayesian Identification of Polynomial NARX Models

引用

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

来源：评论

学校读者我要写书评

暂无评论

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

arXiv

引用

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

来源：评论

学校读者我要写书评

暂无评论

Critical science plan for the Daniel K. Inouye Solar Telescope (DKIST)

arXiv

引用

arXiv 2020年

作者： Rast, Mark P. Bello González, Nazaret Bellot Rubio, Luis Cao, Wenda Cauzzi, Gianna DeLuca, Edward de Pontieu, Bart Fletcher, Lyndsay Gibson, Sarah E. Judge, Philip G. Katsukawa, Yukio Kazachenko, Maria D. Khomenko, Elena Landi, Enrico Martínez Pillet, Valentin Petrie, Gordon J.D. Qiu, Jiong Rachmeler, Laurel A. Rempel, Matthias Schmidt, Wolfgang Scullion, Eamon Sun, Xudong Welsch, Brian T. Andretta, Vincenzo Antolin, Patrick Ayres, Thomas R. Balasubramaniam, K.S. Ballai, Istvan Berger, Thomas E. Bradshaw, Stephen J. Carlsson, Mats Casini, Roberto Centeno, Rebecca Cranmer, Steven DeForest, Craig Deng, Yuanyong Erdélyi, Robertus Fedun, Viktor Fischer, Catherine E. González Manrique, Sergio J. Hahn, Michael Harra, Louise Henriques, Vasco M.J. Hurlburt, Neal E. Jaeggli, Sarah Jafarzadeh, Shahin Jain, Rekha Jefferies, Stuart M. Keys, Peter H. Kowalski, Adam F. Kuckein, Christoph Kuhn, Jeffrey R. Liu, Jiajia Liu, Wei Longcope, Dana James McAteer, R.T. McIntosh, Scott W. McKenzie, David E. Paz Miralles, Mari Morton, Richard J. Muglach, Karin Nelson, Chris J. Panesar, Navdeep K. Parenti, Susanna Parnell, Clare E. Poduval, Bala Reardon, Kevin P. Reep, Jeffrey W. Schad, Thomas A. Schmit, Donald Sharma, Rahul Socas-Navarro, Hector Srivastava, Abhishek K. Sterling, Alphonse C. Suematsu, Yoshinori Tarr, Lucas A. Tiwari, Sanjiv Alexandra, Tritschler Verth, Gary Vourlidas, Angelos Wang, Haimin Wang, Yi-Ming Department of Astrophysical and Planetary Sciences University of Colorado BoulderCO80309 United States Laboratory for Atmospheric and Space Physics University of Colorado BoulderCO80303 United States Kiepenheuer-Institut für Sonnenphysik Freiburg79104 Germany GranadaE-18080 Spain Big Bear Solar Observatory New Jersey Institute of Technology Big Bear CityCA92314 United States National Solar Observatory BoulderCO80303 United States Harvard-Smithsonian Center for Astrophysics CambridgeMA02138 United States Lockheed Martin Solar & Astrophysics Laboratory Palo AltoCA94304 United States Institute of Theoretical Astrophysics Rosseland Centre for Solar Physics University of Oslo OsloN-0315 Norway School of Physics and Astronomy University of Glasgow GlasgowG12 8QQ United Kingdom High Altitude Observatory National Center for Atmospheric Research BoulderCO80307 United States Department of Astronomical Science School of Physical Sciences The Graduate University for Advanced Studies SOKENDAI Tokyo181-8588 Japan National Astronomical Observatory of Japan National Institutes of Natural Science Tokyo181-8588 Japan Instituto de Astrofísica de Canarias La Laguna Tenerife38205 Spain Department of Climate and Space Sciences and Engineering University of Michigan Ann ArborMI48109 United States Department of Physics Montana State University BozemanMT59717 United States NOAA National Centers for Environmental Information BoulderCO80305 United States Department of Mathematics Physics and Electrical Engineering Northumbria University Newcastle upon TyneNE1 8ST United Kingdom Institute for Astronomy University of Hawaii PukalaniHI96768 United States Department of Natural and Applied Sciences University of Wisconsin Green BayWI54311 United States INAF Osservatorio Astronomico di Capodimonte Naples80131 Italy Center for Astrophysics and Space Astronomy University of Colorado BoulderCO80309 United States AFRL Battlespace Environment Division

The Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand and model the basic physical processes that control the structure and dynamics of the Sun and its atmosphere. The first-light DKIST images, released publicly on 29 January 2020, only hint at the extraordinary capabilities which will accompany full commissioning of the five facility instruments. With this Critical Science Plan (CSP) we attempt to anticipate some of what those capabilities will enable, providing a snapshot of some of the scientific pursuits that the Daniel K. Inouye Solar Telescope hopes to engage as start-of-operations nears. The work builds on the combined contributions of the DKIST Science Working group (SWG) and CSP Community members46, who generously shared their experiences, plans, knowledge and dreams. Discussion is primarily focused on those issues to which DKIST will uniquely contribute. Copyright © 2020, The Authors. All rights reserved.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Predicting Risk of Suicide Using Resting State Heart Rate

Predicting Risk of Suicide Using Resting State Heart Rate

引用

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

来源：评论

学校读者我要写书评

暂无评论

Communication scheduling in robust self-triggered MPC for linear discrete-time systems 5

Communication scheduling in robust self-triggered MPC for li...

引用

5th IFAC Workshop on Distributed Estimation and control in Networked systems, NecSys 2015

作者： Brunner, Florian D. Gommans, T.M.P. Heemels, W.P.M.H. Allgöwer, Prank 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 consider a networked control system consisting of a physical plant, an actuator, a sensor, and a controller that is connected to the actuator and sensor via a communication network. The plant is described by a linear discrete-time system subject to additive disturbances. In order to reduce the required number of communications in the system, we propose a robust self-triggered model predictive controller based on rollout techniques that robustly asymptotically stabilizes a certain periodic sequence of sets in the state space while guaranteeing robust satisfaction of hard state and input constraints. At periodically occurring scheduling times, the self-triggered model predictive control algorithm determines the times at which the control input and plant measurement are updated in the time span until the next scheduling time. We establish a certain upper bound on the average sampling rate in the closed-loop system. Moreover, we show how increasing the asymptotic bound on the system state, which is a design parameter in the control scheme, can be used to further reduce the average number of communications in the system. © 2015, IF AC (International Federation of automatic control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Closed loop systems

来源：评论

学校读者我要写书评

暂无评论

Estimation of fingertip force from surface EMG a multivariate Bayesian mixture of experts approach 8

Estimation of fingertip force from surface EMG a multivariat...

引用

8th International Conference on Bio-Inspired systems and Signal Processing, BIOSIGNALS 2015

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

ISBN: (纸本)9789897580697

Improving the dexterity of active prostheses is a major research area amalgamating machine learning algorithms and biosignals. A recent research niche has emerged from this-providing proportional control to a prosthetic hand by modelling the force applied at the fingertips using surface electromyography (sEMG). The publicly released NinaPro database contains sEMG recording for 6 degree-of-freedom force activations for 40 intact subjects. In this preliminary study the authors successfully perform multivariate force regression using Bayesian mixture of experts (MoE). The accuracy of the model is compared to the benchmark set by the authors of NinaPro;comparable performance is achieved, however in this work a lower dimensional feature extraction representation obtains the best modelling accuracies, hence reducing training time. Inherent to the Bayesian framework is the inclusion of uncertainty in the model structure, providing a natural step in obtaining confidence bounds on the predictions. The MoE model used in this paper provides a powerful method for modelling force regression with application to actively controlling prosthetic and robotic arms for rehabilitation purposes, resulting in highly refined movements.

关键词： Learning algorithms

来源：评论

学校读者我要写书评

暂无评论

Optimal control of quantum systems with SU(1,1)dynamical symmetry

引用

control Theory and Technology 2015年第3期13卷 211-220页

作者： Wenbin DONG Rebing WU Jianwu WU Chunwen LI Tzyh-Jong TARN Department of Automation Tsinghua University Center for Quantum Information Science and Technology Tsinghua National Laboratory for Information Science and Technology(TNlist) Beijing Aerospace Automatic Control Institute Electrical and Systems Engineering Department Washington University in St.Louis

SU（1,1） dynamical symmetry is of fundamental importance in analyzing unbounded quantum systems in theoretical and applied physics. In this paper, we study the control of generalized coherent states associated with quantum systems with SU（1,1） dynamical symmetry. Based on a pseudo Riemannian metric on the SU（1,1） group, we obtain necessary conditions for minimizing the field fluence of controls that steer the system to the desired final state. Further analyses show that the candidate optimal control solutions can be classified into normal and abnormal extremals. The abnormal extremals can only be constant functions when the control Hamiltonian is non-parabolic, while the normal extremals can be expressed by Weierstrass elliptic functions according to the parabolicity of the control Hamiltonian. As a special case, the optimal control solution that maximally squeezes a generalized coherent state is a sinusoidal field, which is consistent with what is used in the laboratory.

关键词： Quantum control optimal control dynamical symmetry

来源：评论

学校读者我要写书评

暂无评论

Heterogeneity of time delays determines synchronization of coupled oscillators

引用

Physical Review E 2016年第1期94卷 012209-012209页

作者： Spase Petkoski Andreas Spiegler Timothée Proix Parham Aram Jean-Jacques Temprado Viktor K. Jirsa Aix-Marseille Université Inserm INS UMR_S 1106 13005 Marseille France Aix-Marseille Université CNRS ISM UMR 7287 13288 Marseille France Department of Automatic Control and Systems Engineering University of Sheffield Sheffield S10 2TN United Kingdom

Network couplings of oscillatory large-scale systems, such as the brain, have a space-time structure composed of connection strengths and signal transmission delays. We provide a theoretical framework, which allows treating the spatial distribution of time delays with regard to synchronization, by decomposing it into patterns and therefore reducing the stability analysis into the tractable problem of a finite set of delay-coupled differential equations. We analyze delay-structured networks of phase oscillators and we find that, depending on the heterogeneity of the delays, the oscillators group in phase-shifted, anti-phase, steady, and non-stationary clusters, and analytically compute their stability boundaries. These results find direct application in the study of brain oscillations.

关键词： Neuroscience Synchronization Coupled oscillators

来源：评论

学校读者我要写书评

暂无评论

An improved image distortion correction algorithm

An improved image distortion correction algorithm

引用

International Conference on Multimedia, Communication and Computing Application, MCCA 2014

作者： Lv, S.T. Ding, Y. Wei, H.L. Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of Education School of Aerospace Engineering Beijing Institute of Technology Beijing China Department of Automatic Control and Systems Engineering University of Sheffield United Kingdom

ISBN: (纸本)9781138027756

In the optical measuring apparatus based on the TV camera, the image distortion usually occurs due to the defects of optical system design and manufacture or the distortion of the image sensor. For the common barrel distortion and pincushion distortion, this paper proposes an improved distortion correction algorithm based on the equivalent spherical surface, and processes the corrected image with bilinear interpolation, scaling and edge filling algorithm. This text uses actual images with barrel distortion and pincushion distortion to conduct an experiment which verifies that the proposed algorithm can not only efficiently correct the spherical distortion in the image, but also can ensure the integrity of its information and frame. © 2015 Taylor & Francis group, London.

关键词： Image enhancement

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：