847,346 research outputs found
A computational approach for cam size optimization of disc cam-follower mechanisms with translating roller followers
The main objective of this work is to present a computational approach for design optimization of disc cam mechanisms with eccentric translating roller followers. For this purpose, the objective function defined here takes into account the three major parameters that influence the final cam size, namely the base circle radius of the cam, the radius of the roller and the offset of the follower. Furthermore, geometric constraints related to the maximum pressure angle and minimum radius of curvature are included to ensure good working conditions of the system. Finally, an application example is presented and used to discuss the main assumptions and procedure adopted throughout this work.Fundação para a Ciência e a Tecnologia (FCT
Feature Selection Library (MATLAB Toolbox)
Feature Selection Library (FSLib) is a widely applicable MATLAB library for
Feature Selection (FS). FS is an essential component of machine learning and
data mining which has been studied for many years under many different
conditions and in diverse scenarios. These algorithms aim at ranking and
selecting a subset of relevant features according to their degrees of
relevance, preference, or importance as defined in a specific application.
Because feature selection can reduce the amount of features used for training
classification models, it alleviates the effect of the curse of dimensionality,
speeds up the learning process, improves model's performance, and enhances data
understanding. This short report provides an overview of the feature selection
algorithms included in the FSLib MATLAB toolbox among filter, embedded, and
wrappers methods.Comment: Feature Selection Library (FSLib) 201
High resolution in-vivo MR-STAT using a matrix-free and parallelized reconstruction algorithm
MR-STAT is a recently proposed framework that allows the reconstruction of
multiple quantitative parameter maps from a single short scan by performing
spatial localisation and parameter estimation on the time domain data
simultaneously, without relying on the FFT. To do this at high-resolution,
specialized algorithms are required to solve the underlying large-scale
non-linear optimisation problem. We propose a matrix-free and parallelized
inexact Gauss-Newton based reconstruction algorithm for this purpose. The
proposed algorithm is implemented on a high performance computing cluster and
is demonstrated to be able to generate high-resolution (
in-plane resolution) quantitative parameter maps in simulation, phantom and
in-vivo brain experiments. Reconstructed and values for the gel
phantoms are in agreement with results from gold standard measurements and for
the in-vivo experiments the quantitative values show good agreement with
literature values. In all experiments short pulse sequences with robust
Cartesian sampling are used for which conventional MR Fingerprinting
reconstructions are shown to fail.Comment: Accepted by NMR in Biomedicine on 2019-12-0
Tvarování vstupu pro podtlumené systémy
The main aim of this paper is to provide possibility to test and validate multiple damping and input shaping methods for underdamped systems. Mathematical model for specific development and demonstration was created in Matlab Simscape environment. Additional Matlab Simulink system was modelled to achieve proper data acquisition and comparison in contrast to plain system without any special damping methods.Hlavním cílem této práce je poskytnout možnost testování a validace více metod tlumení a vstupních tvarů u podtlumených systémů. Matematický model pro specifický vývoj a demonstraci byl vytvořen v prostředí Matlab Simscape. Další systém Matlab Simulink byl modelován tak, aby dosáhl správného získávání a srovnání dat v porovnání s běžným systémem bez zvláštních metod tlumení
Matlab code for Lyapunov exponents of fractional order systems
In this paper the Benettin-Wolf algorithm to determine all Lyapunov exponents
for a class of fractional-order systems modeled by Caputo's derivative and the
corresponding Matlab code are presented. First it is proved that the considered
class of fractional-order systems admits the necessary variational system
necessary to find the Lyapunov exponents. The underlying numerical method to
solve the extended system of fractional order, composed of the initial value
problem and the variational system, is the predictor-corrector
Adams-Bashforth-Moulton for fractional differential equations. The Matlab
program prints and plots the Lyapunov exponents as function of time. Also, the
programs to obtain Lyapunov exponents as function of the bifurcation parameter
and as function of the fractional order are described. The Matlab program for
Lyapunov exponents is developed from an existing Matlab program for Lyapunov
exponents of integer order. To decrease the computing time, a fast Matlab
program which implements the Adams-Bashforth-Moulton method, is utilized. Four
representative examples are considered.Comment: accepte
- …
