Varela Aldas, José
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Varela Aldas, José
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Ambato
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josevarela@uti.edu.ec
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57192546163

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Effects of a dual intervention (motor and virtual reality-based cognitive) on cognition in patients with mild cognitive impairment: a single-blind, randomized controlled trial

2024 , Buele, Jorge , Avilés-Castillo, Fátima , Carolina Del-Valle-Soto , Varela Aldas, José , Guillermo Palacios-Navarro

Abstract Background The increase in cases of mild cognitive impairment (MCI) underlines the urgency of finding effective methods to slow its progression. Given the limited effectiveness of current pharmacological options to prevent or treat the early stages of this deterioration, non-pharmacological alternatives are especially relevant. Objective To assess the effectiveness of a cognitive-motor intervention based on immersive virtual reality (VR) that simulates an activity of daily living (ADL) on cognitive functions and its impact on depression and the ability to perform such activities in patients with MCI. Methods Thirty-four older adults (men, women) with MCI were randomized to the experimental group (n = 17; 75.41 ± 5.76) or control (n = 17; 77.35 ± 6.75) group. Both groups received motor training, through aerobic, balance and resistance activities in group. Subsequently, the experimental group received cognitive training based on VR, while the control group received traditional cognitive training. Cognitive functions, depression, and the ability to perform activities of daily living (ADLs) were assessed using the Spanish versions of the Montreal Cognitive Assessment (MoCA-S), the Short Geriatric Depression Scale (SGDS-S), and the of Instrumental Activities of Daily Living (IADL-S) before and after 6-week intervention (a total of twelve 40-minutes sessions). Results Between groups comparison did not reveal significant differences in either cognitive function or geriatric depression. The intragroup effect of cognitive function and geriatric depression was significant in both groups (p < 0.001), with large effect sizes. There was no statistically significant improvement in any of the groups when evaluating their performance in ADLs (control, p = 0.28; experimental, p = 0.46) as expected. The completion rate in the experimental group was higher (82.35%) compared to the control group (70.59%). Likewise, participants in the experimental group reached a higher level of difficulty in the application and needed less time to complete the task at each level. Conclusions The application of a dual intervention, through motor training prior to a cognitive task based on Immersive VR was shown to be a beneficial non-pharmacological strategy to improve cognitive functions and reduce depression in patients with MCI. Similarly, the control group benefited from such dual intervention with statistically significant improvements. Trial registration ClinicalTrials.gov NCT06313931; https://clinicaltrials.gov/study/NCT06313931.

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Salty Taste Intensity Classifier Through Multivariate Analysis

2022 , Fuentes E.M. , Varela Aldas, José , Verdú S. , Grau Meló R. , Barat J.M. , Alcañiz M.

Voltammetric electronic Tongues (VET) are widely used on the industry, especially when focused on sample classification, adulteration recognizement and quality control, a VET equipment developed by the Interuniversity Institute of Molecular Recognition and Technological Development of the UPV-UV (IDM) was employed to develop the study, the results of each test were 7920 data, and different Chloride of Sodium concentrations such as 1.25 mM, 2.5 mM, 5 mM and 10 mM were tested. This is a part of a series of studies related with basic flavor recognize though VET, so the aim of this work was to study the capability of the VET to recognize different intensity of salt concentrations, supported on multivariate analysis. The results showed a concordance of more than 70.31% in the separation of samples, allowing to conclude as acceptable the performance of the classifier and the data acquired through the voltammetric electronic tongues. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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Voltammetric Electronic Tongues Applied to Classify Sucrose Samples Through Multivariate Analysis

2021 , Fuentes, E.M. , Varela Aldas, José , Verdú S. , Meló R.G. , Alcañiz M.

The aim of the present study was to classify samples of sugar with different concentrations through a Voltammetric Electronic tongues (VET), with a generic pulse sequence consisted of 22 pulses ranging from –1000 mV to + 1000 mV with a duration of 20 ms/pulse over different samples such as 1.25mM, 2.5mM, 5mM and 10mM, of sucrose concentration, these were measured 4 times each concentration and the test was developed 4 times, giving a total number of 506.880 data supervised learning algorithm using support vector machine was employed, choosing a linear function as a classifying element. In the training, 75% of the data was used to determine the coefficients of the classification function, and the remaining (25%) was used to evaluate the performance of the proposal. The results showed a concordance of more than 80% in the separation of sample, allowing to conclude as acceptable the performance of the classifier and the data acquired through the voltammetric tongue. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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Optimal cooperative control of mobile robots based on Pontryagin's Minimum Principle

2022 , Varela Aldas, José

This work presents the cooperative control with optimization for positioning of mobile robots based on Pontryagin's Minimum Principle. The problem to be solved is the minimum energy related to the control actions of the robots. The objective function is subject to the equations of states of the triangular formation of the 3 mobile robots and is restricted to boundary conditions that include the desired form parameters. The mathematical model of the system is based on the kinematic transformation of the position of the robots towards the parameters of the formation. To solve the differential equations obtained, the shooting method is programmed for two initial value problems. The results show the evolution of the robots' positions and the positioning errors that tend to zero, validating this proposal through simulation. In addition, the control actions allow determining the energy index to compare it with a previous work, achieving a lower value. © 2022 IEEE.

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Construction of a WBGT index meter using low cost devices

2020 , Varela Aldas, José , Fuentes, E.M. , Ruales, María Belén , Ichina, C.

Appropriate working conditions can improve the working performance of an employee on a company, one of the main concerns nowadays is the thermal stress, due to the affection not only to the productivity of an employee but also for the risk of affections to his health, in this sense, WBGT (Wet-Bulb Globe Temperature) index is widely proved to define thermal discomfort and thermal stress but in some cases is out of reach due to its cost or availability on a certain region of the world, so this work explains the construction of a low cost device WBGT meter built by an Arduino pro mini, three lm35 temperature sensors and an LCD to install the electronic system; Globe temperature and wet bulb temperature was achieved using a matte black sphere and moistened fabric, respectively. After testing the dispositive, the collected information was sent to a computer through serial communication for further analysis which showed acceptable errors on the measurement of the WBGT index taken indoors and outdoors thru the device and compared to the data obtained by a commercial WBGT meter. © Springer Nature Switzerland AG 2020.

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Quadcopters Control Using Online Dynamic Mode Decomposition

2023 , Guevara B.S. , Recalde L.F. , Varela Aldas, José , Gandolfo D.C. , Toibero J.M.

Over the past few years, unmanned aerial vehicles (UAVs) have gained popularity in a wide range of applications such as delivery services, inspection, and monitoring. However, for these applications to be safe and efficient, an accurate model of the UAV's dynamic is essential. In this article, the authors propose a novel control system for the DJI Matrice 100 quadcopter based on the online dynamic mode decomposition with control (DMDc) algorithm and iterative optimal estimation techniques. The online DMDc algorithm enables the identification of the system's dynamic, a critical requirement for an adaptive control. By decomposing the quadcopter's system into dynamic modes, the authors create a precise model of the system's behavior using a Hardware in the Loop (HiL) framework, which is used to design the control system based on inverse dynamics. The adaptive control system can adjust its parameters based on changes in the system's behavior, making it suitable for UAV operations in unpredictable environments. These results demonstrate that the proposed control system significantly improves performance in the presence of disturbances.The research contributes to the field of UAV control and highlights the potential of DMD and adaptive control techniques for enhancing the safety and efficiency of UAV operations. Copyright © 2023 The Authors.

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Inverse kinematics of a redundant manipulator robot using constrained optimization

2020 , Varela Aldas, José , Ayala-Chauvin, Manuel Ignacio , Andaluz, V.H. , Santamaría, M.

Redundant manipulative robots are characterized by greater manipulability improving performance but complicating inverse kinematics, on the other hand, optimization techniques allow solving complex problems in robotics applications with greater efficiency. This paper presents the inverse kinematics of a redundant manipulative robot with four degrees of freedom to track a desired trajectory, and considering constraint in manipulability. The optimization problem is proposed using the quadratic position errors of the operative end and the constraint is established by a manipulability index, for this the kinematic model of the robot is determined. The results show the points of singularity of the robot and the performance of the proposal implemented, observing the positional errors and the manipulability for each point of the trajectory. In addition, the optimization is evaluated for two desired manipulability values. Finally, it is concluded that the implemented method optimizes the inverse kinematics to track the desired path while constraining the manipulability. © Springer Nature Switzerland AG 2020.

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Virtual System for Industrial Processes: Distillation Towers

2021 , Jacome E.M. , Toaquiza J.F. , Mullo G.M. , Andaluz V.H. , Varela Aldas, José

In this paper a realistic and intuitive virtual environment of a distillation tower system is developed. The three-dimensional model of the system is based on a real system, which is replicated in Blender software to be later implemented in Unity, in order to simulate its behavior. By showing the evolution of the system, control and monitoring maneuvers are implemented, so that the virtual animation is similar to a real process. The application developed is intended to provide support in the learning process of an operator in the work area. © 2021, Springer Nature Switzerland AG.

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Dynamics of a Unicycle-Type Wheeled Mobile Manipulator Robot

2020 , Varela Aldas, José , Chicaiza, F.A. , Andaluz V.H.

Mathematical modeling is widely used in robotics to display behaviors and design control algorithms; the dynamic model of a robot describes the movements considering the action of internal and external forces of the system. This paper presents the dynamics of a unicycle mobile manipulator robot using the Euler-Lagrange proposal and conditioning the model to obtain the output velocities in the robot from the desired velocities. Additionally, the dynamic model is complemented by the identification of parameters using experimental data obtained from the AKASHA robot. The results present the signals applied in the identification, the values of the dynamic constants are found and the validation data which indicate a correct performance of the proposal are graphically shown. © 2020, Springer Nature Switzerland AG.

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Mobile Manipulator for Hospital Care Using Firebase

2022 , Varela Aldas, José , Buele, Jorge , Guerrero-Núñez S , Andaluz V.H.

The COVID-19 pandemic has shown that the use of the technology in medicine is no longer a luxury, but a necessity. The use of the robotics in the treatment of diseases and physical therapies is limited in Latin America due to the high acquisition and maintenance costs. This document proposes the design, development, and evaluation of a robotic system for the guided monitoring of patients, through remote control using a mobile application. Within the methodology, four phases were proposed: planning, design, development, and evaluation. The 3D design is done using the Tinkercad software, which facilitates the construction of the pieces using 3D printing technology. The ESP32 board is the main element that receives the signals from the sensors and controls the actions of the actuators through the orders received from Firebase. For the development of the application, App inventor is used, building a friendly and easy-to-use interface. To validate this proposal, experimental tests were carried out with two patients in a medical center. In addition, a parameter compliance questionnaire was applied to the robot, obtaining a score of 92.6%, and the mobile application obtained 72.5% in the usability test. All this confirms an efficient care proposal, with a reduced investment. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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