This article introduces the Zeffiro interface (ZI) version 2.2 for brain imaging. ZI aims to provide a simple, accessible and multimodal open source platform for finite element method (FEM) based and graphics processing unit (GPU) accelerated forward and inverse computations in the Matlab environment. It allows one to (1) generate a given multi-compartment head model, (2) to evaluate a lead field matrix as well as (3) to invert and analyze a given set of measurements. GPU acceleration is applied in each of the processing stages (1)-(3). In its current configuration, ZI includes forward solvers for electro-/magnetoencephalography (EEG) and linearized electrical impedance tomography (EIT) as well as a set of inverse solvers based on the hierarchical Bayesian model (HBM). We report the results of EEG and EIT inversion tests performed with real and synthetic data, respectively, and demonstrate numerically how the inversion parameters affect the EEG inversion outcome in HBM. The GPU acceleration was found to be essential in the generation of the FE mesh and the LF matrix in order to achieve a reasonable computing time. The code package can be extended in the future based on the directions given in this article.
This paper aims to study the horizontal vibration dynamic characteristics of high-speed elevator by considering the combined effect of airflow and guiding system. The relationships of lateral force and overturning moment with horizontal displacement, deflection angle displacement and rated speed of the car are mathematically solved, and the horizontal vibration dynamic model of the car under the two excitations is established. For case model, the natural frequency and horizontal vibration response of the car are studied, and the guide-rail excitation frequency and car natural frequency are compared and analyzed. The results indicate that the higher the rated speed is, the more obvious the resonance phenomenon between the guide-rail and car will be in a certain range; the effect of airflow on horizontal vibration acceleration of the car with a speed lower than 6 m/s is small, but when the speed is over 6 m/s, the airflow will greatly affect the single-peak value of horizontal vibration acceleration, which is approximately a quadratic relationship; the deflection angle displacement has an increasing influence on horizontal vibration dynamic response with the increasing speed. The conclusions provide a theoretical guidance for the research and control on the horizontal vibration of high-speed elevator.
Aiming at the problem of transverse vibration of high-speed elevator caused by surface roughness excitation of guide rail and relative motion between car and car frame, firstly, this paper establishes an eight-degree-of-freedom active control model for the transverse vibration of the high-speed elevator separated of car from the car frame. Secondly, the transverse vibration state equation of the high-speed elevator is derived. The H
2 norm is used to minimize the vibration acceleration of the car system. Based on Linear matrix inequality (LMI) optimization technology, a robust controller for the high-speed elevator is designed. Finally, the robust controller is solved by MATLAB and its simulation analysis is carried out. The results show that the vibration of the car and the car frame is inconsistent in actual operation. At the same time, the simulation results also show that the root mean square value, mean value and maximum value of the acceleration of the transverse vibration of the car and the car frame are reduced by more than 19% after using the robust controller. Therefore, the robust controller designed in this paper can effectively suppress the transverse vibration of the vibration car system.
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