In this work, a new method to design TMS coils is presented. It is based on the inclusion of the concept of stream function of a quasi-static electric current into a boundary element method. The proposed TMS coil design approach is a powerful technique to produce stimulators of arbitrary shape, and remarkably versatile as it permits the prototyping of many different performance requirements and constraints. To illustrate the power of this approach, it has been used for the design of TMS coils wound on rectangular flat, spherical and hemispherical surfaces, subjected to different constraints, such as minimum stored magnetic energy or power dissipation. The performances of such coils have been additionally described; and the torque experienced by each stimulator in the presence of a main magnetic static field have theoretically found in order to study the prospect of using them to perform TMS and fMRI concurrently. The obtained results show that described method is an efficient tool for the design of TMS stimulators, which can be applied to a wide range of coil geometries and performance requirements.
ABSTRACT:The theoretical teaching of Computer Architecture is not suitable longer. In the present time, students claim for a learning-by-doing according to their dynamic and active character. Nowadays, interactive teaching is possible thanks to the decrease in the prices of the Field Programmable Gate Arrays. This paper proposes a learning-by-doing methodology to teach Computer Architecture to first-year student who belong to a digital-native generation. The method consists in developing a whole computer from scratch while they are introduced to hardware description languages (HDL) and programmable logic devices. Firstly, students design each and every element of the computer by VHDL language. Later on, they interconnect the verified elements and test the complete computer. A FPGA-based board is needed to implement and check the correct performance of the designed computer. This educational approach is intended to be used with first-year students from Computer Engineering Degree, thus, it is the first experience of the students with the basics of Computer Architecture. Students have a computer and a FPGA-based board in anytime. In the final exam, a design of a different computer is propounded. Computer testing and programming is a requirement to pass. The high percentage of passed students corroborated the success of the methodology. Thus, computer functioning and construction is understood by a hands-on methodology at the same time as VHDL language and FPGA technology are introduced. Lack attention is avoided since students keep a dynamic role working with their personal computer and FPGA at all times. ß 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23: [464][465][466][467][468][469][470] 2015; View this article online at wileyonlinelibrary.com/ journal/cae;
Objective. Interleaving TMS (transcranial magnetic stimulation) with fMRI (functional Magnetic Resonance Imaging) is a promising technique to study functional connectivity in the human brain, but its development is being restricted by technical limitations, such as that due to the interaction of the TMS current pulses with the magnetic fields of an MRI scanner. In this work, a TMS coil design method capable of controlling Lorentz forces experienced by the coil in the presence of static magnetic fields is presented. Approach. The suggested approach is based on an existing inverse boundary element method (IBEM) for TMS coil design, in which new electromagnetic computational models of the Lorentz forces have been included to be controlled in the design process. Main results. To demonstrate the validity of this technique, it has been used for the design and simulation of TMS coils wound on rectangular flat, spherical and hemispherical surfaces with improved mechanical stability. The obtained results confirm that TMS coils with reduced Lorentz forces inside the static main field of an MRI scanner can be produced, which is achieved to the detriment of other coil performance parameters. Significance. The proposed approach provides an efficient tool to design TMS stimulators of a wide range of coil geometries with improved mechanical stability, which can be extremely useful to overcome current limitations for interleaved TMS-fMRI.
Motivated by the effects of deregulation over power quality and the subsequent need of new types of measurements, this paper assesses different implementations of an estimate for the spectral kurtosis, considered as a low-level harmonic detection. Performance of a processor-based system is compared with a field programmable gate array (FPGA)-based solution, in order to evaluate the accuracy of this processing function for implementation in autonomous measurement equipment. The fourth-order spectrum, with applications in different fields, needs advanced digital signal processing, making it necessary to compare implementation alternatives. In order to obtain reproducible results, the implementations have been developed using common design and programming tools. Several characteristics of the implementations are compared, showing that the increasing complexity and reduced cost of the current FPGA models make the implementation of complex mathematical functions feasible. We show that FPGAs improve the processing capability of the best processor using an operating frequency 33 times lower. This fact strongly supports its implementation in hand-held instruments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.