ARTICLE | doi:10.20944/preprints202302.0092.v1
Subject: Computer Science And Mathematics, Computer Science Keywords: Adaptive Algorithm; Tremor Suppression; LMS; Parkinson
Online: 6 February 2023 (09:09:01 CET)
The increase in life expectancy, according to the World Health Organization, is a fact, and with it rises the incidence of age-related neurodegenerative diseases. The most recurrent symptoms are those associated with tremors resulting from Parkinson's Disease (PD) or Essential Tremors (ET). The main alternatives for the treatment of these patients are medication and surgical intervention, which sometimes have restrictions and side effects. Through computer simulations in Matlab software, this work investigates the performance of adaptive algorithms based on least mean squares (LMS) to suppress tremors in upper limbs, especially in the hands. The signals resulting from pathological hand tremors, related to PD, present components at frequencies that vary between 3~Hz and 6~Hz, with the more significant energy present in the fundamental and second harmonics, while physiological hand tremors, referred to as ET, vary between 4~Hz and 12~Hz. We simulated and used these signals as reference signals in adaptive algorithms, Filtered-x Least Mean Square (Fx-LMS), Filtered-x Normalized Least Mean Square (Fx-NLMS), and a hybrid Fx-LMS\&NLMS purpose. Our results showed that the vibration control provided by the Fx-LMS\&LMS algorithm is the most suitable for physiological tremors. For pathological tremors, we have used a proposed algorithm with a filtered sinusoidal input signal, Fsinx-LMS, which presented the best results in this specific case.
ARTICLE | doi:10.20944/preprints202103.0313.v1
Subject: Social Sciences, Education Keywords: Learning Management System (LMS); perceived role; readiness; integration
Online: 11 March 2021 (11:06:24 CET)
The rapid development of information and communication technologies has led to the use of new and digital technologies in education which involves combinations of text, graphics, audio, video, animations and other eLearning resources such as authoring tools, Learning Management System (LMS), Mobile learning and others. Arguably, using LMS leaves much to be desired. The inherent problem here is that the future of extensive adoption of ICT via LMS to enhance and promote classroom interaction in Open and Distance Learning (ODL) is bleak. This is worrisome given that the country is lagging far behind in the innovative use of this web 2.0 technology to impart knowledge. Further, the low-level application of LMS in instruction connotes the loss of inherent advantages in its adoption. Also, the online setting which makes students less nervous and interactive, sharing of ideas and viewpoints; and a host of other benefit will be lost. While evidence has shown that LMS is not a new phenomenon, the use of LMS in ODL is still at its infancy, particularly in Nigeria. Research in this area is rare. A quick search on prominent research databases could testify that. It is on this thrust that this study investigates University of Ibadan undergraduate students’ perceived roles and readiness towards integration of learning management system into teaching and learning.
ARTICLE | doi:10.20944/preprints202202.0282.v1
Subject: Computer Science And Mathematics, Computer Science Keywords: content creation tools; plugin; Moodle; e-learning technologies; LMS; XML file; quiz
Online: 22 February 2022 (16:23:33 CET)
The use of Learning Management Systems (LMS) has had a rapid growth over the last decades. Great efforts have been recently made to assess the level of performance of the students online due to the COVID-19 pandemic. Faculty members with limited experience in the use of LMS such as Moodle, Edmodo, MOOC, Blackboard and Google Classroom can have some problems creat-ing online tests. In this work, a new plugin for Moodle is presented: FastTest PlugIn. This plugin is based on a Microsoft® Excel spreadsheet and it can be used to export questions to Moodle. Us-ers of FastTest PlugIn can create question pools in an easy and intuitive way. A literature review about plugins used to import/export questions in Moodle is carried out. Then, the characteristics of FastTest PlugIn are presented. At the end, the characteristics of the main plugins found in the literature are discussed and compared with the ones of FastTest PlugIn.
ARTICLE | doi:10.20944/preprints202302.0031.v1
Subject: Physical Sciences, Applied Physics Keywords: chaotic systems; Van der Pol oscillator; drive-response; synchronization of chaotic systems; global chaos synchronization; deterministic artificial intelligence; feedforward; feedback; non-linear adaptive control; online estimation; recursive least squares (RLS); exponential forgetting; Kalman filter; least mean squares (LMS).
Online: 2 February 2023 (06:17:48 CET)
The Van der Pol oscillator is a chaotic non-linear system. Small perturbations in initial conditions may result in wildly different trajectories. Because of its chaotic nature, controlling, or forcing, the behavior of a Van der Pol oscillator is difficult to achieve through traditional adaptive control methods. Connecting two Van der Pol oscillators together where the output of one oscillator, the driver, drives the behavior of its partner, the responder, is a proven technique for controlling the Van der Pol oscillator. Deterministic AI (DAI) is an adaptive feedback control method that leverages the known physics of the Van der Pol system to learn optimal system parameters for the forcing function. We assessed the performance of DAI employing three different online parameter estimation algorithms. Our evaluation criteria include mean absolute error (MAE) between the target trajectory and the response oscillator trajectory over time. RLS with exponential forgetting (RLS-EF) had the lowest MAE overall, with a 2.46% reduction in error. However, another method was notable. Least Mean Squares with normalized gradient adaptation (LMS-NG) had worse initial error in the first 10% of the simulation, but after that point had consistently better performance. We found that over the last 90% of the simulation, DAI with LMS-NG had a 48.7% reduction in MAE compared to feedforward alone.