Analysis of reliable deployment of TDOA local positioning architectures

.Local Positioning Systems (LPS) are supposing an attractive research topic over the last few years. LPS are ad-hoc deployments of wireless sensor networks for particularly adapt to the environment characteristics in harsh environments. Among LPS, those based on temporal measurements stand out for their trade-off among accuracy, robustness and costs. But, regardless the LPS architecture considered, an optimization of the sensor distribution is required for achieving competitive results. Recent studies have shown that under optimized node distributions, time-based LPS cumulate the bigger error bounds due to synchronization errors. Consequently, asynchronous architectures such as Asynchronous Time Difference of Arrival (A-TDOA) have been recently proposed. However, the A-TDOA architecture supposes the concentration of the time measurement in a single clock of a coordinator sensor making this architecture less versatile. In this paper, we present an optimization methodology for overcoming the drawbacks of the A-TDOA architecture in nominal and failure conditions with regards to the synchronous TDOA. Results show that this optimization strategy allows the reduction of the uncertainties in the target location by 79% and 89.5% and the enhancement of the convergence properties by 86% and 33% of the A-TDOA architecture with regards to the TDOA synchronous architecture in two different application scenarios. In addition, maximum convergence points are more easily found in the A-TDOA in both configurations concluding the benefits of this architecture in LPS high-demanded applicationS

Table Organization Optimization in Schools for Preserving the Social Distance during the COVID-19 Pandemic

[EN] The COVID-19 pandemic has supposed a challenge for education. The school closures during the initial coronavirus outbreak for reducing the infections have promoted negative effects on children, such as the interruption of their normal social relationships or their necessary physical activity. Thus, most of the countries worldwide have considered as a priority the reopening of schools but imposing some rules for keeping safe places for the school lessons such as social distancing, wearing facemasks, hydroalcoholic gels or reducing the capacity in the indoor rooms. In Spain, the government has fixed a minimum distance of 1.5 m among the students’ desks for preserving the social distancing and schools have followed orthogonal and triangular mesh patterns for achieving valid table dispositions that meet the requirements. However, these patterns may not attain the best results for maximizing the distances among the tables. Therefore, in this paper, we introduce for the first time in the authors’ best knowledge a Genetic Algorithm (GA) for optimizing the disposition of the tables at schools during the coronavirus pandemic. We apply this GA in two real-application scenarios in which we find table dispositions that increase the distances among the tables by 19.33% and 10%, respectively, with regards to regular government patterns in these classrooms, thus fulfilling the main objectives of the paper.SIMinisterio de Ciencia, Innovación y Universidade

Characterization of AGV Localization System in Industrial Scenarios Using UWB Technology

[EN] Automatic guided vehicles (AGVs) are indispensable elements for the advancement of Industry 4.0 and the digital transformation of factories. These industrial vehicles use embedded intelligence to orient themselves and plan their routes in the short term with the aim of achieving a collaborative, safe, and efficient environment, increasing the competitiveness of industrial plants. However, AGVs still present some challenges that do not allow the full deployment of these vehicles for precision industrial tasks. For this reason, in this article, we propose a localization system to enhance the position determination of AGVs in the industrial plant. This system is based on a wireless ad hoc network that modulates the localization signal through ultra-wideband (UWB) technology to take advantage of the very short duration of the emitted pulses granting robustness against the multipath and non-line-of-sight (NLOS) negative effects typical of industrial environments. In addition, we optimize the location of the architecture sensors through a metaheuristic algorithm (MA-VND-Chains) that requires the definition of the system localization uncertainties given a particular sensor arrangement. For this purpose, we introduce in this article the most complete characterization of the uncertainties of the time difference of arrival (TDOA) localization architecture based on noise, clock, and multipath effects. This allows us to finally obtain localization errors up to six centimeters, thus attaining the required accuracy for AGVs to address high-demanded accuracy applications within the industrial plant.SIThis work was supported in part by the Spanish Ministry of Science and Innovation Project under Grant PID2019-108277GB-C21/ AEI/10.13039/501100011033 and in part by the University of León. The Associate Editor coordinating the review process was Dr. Yong Yan.Agencia Estatal de Investigació

Digital Twin for Automatic Transportation in Industry 4.0

[EN] Industry 4.0 is the fourth industrial revolution consisting of the digitalization of processes facilitating an incremental value chain. Smart Manufacturing (SM) is one of the branches of the Industry 4.0 regarding logistics, visual inspection of pieces, optimal organization of processes, machine sensorization, real-time data adquisition and treatment and virtualization of industrial activities. Among these tecniques, Digital Twin (DT) is attracting the research interest of the scientific community in the last few years due to the cost reduction through the simulation of the dynamic behaviour of the industrial plant predicting potential problems in the SM paradigm. In this paper, we propose a new DT design concept based on external service for the transportation of the Automatic Guided Vehicles (AGVs) which are being recently introduced for the Material Requirement Planning satisfaction in the collaborative industrial plant. We have performed real experimentation in two different scenarios through the definition of an Industrial Ethernet platform for the real validation of the DT results obtained. Results show the correlation between the virtual and real experiments carried out in the two scenarios defined in this paper with an accuracy of 97.95% and 98.82% in the total time of the missions analysed in the DT. Therefore, these results validate the model created for the AGV navigation, thus fulfilling the objectives of this paper.SIMinisterio de Ciencia, Innovación y Universidade

Validation of the Scale of Basic Psychological Needs towards Physical Exercise, with the Inclusion of Novelty

The purpose of this study was to validate and adapt to the Spanish context of Physical Education, the Spanish version of the Scale of Basic Psychological Needs in the context of physical exercise, with the incorporation of novelty to the scale. The sample that took part in the study was 2372 people from 16 to 48 years old from the province of Almeria. In order to analyze the psychometric properties of the scale, several analyses have been carried out. The results have offered support both for the eight-factor structure and for the higher-order double model where the eight subscales are joined into two constructs called frustration and satisfaction. The structure of both models was invariant with respect to gender and age. Cronbach’s alpha values were above 0.70 in the subscales and scales; and adequate levels of temporal stability. In addition, the subfactors pertaining to the satisfaction of basic psychological needs positively predicted the intrinsic motivation for physical activity, while each of the subfactors of the frustration of psychological needs predicted it negatively. The results of this study provide evidence of the reliability and validity of the BPNS in the Spanish context of physical activity

Estudio de Evaluación Financiera de una PCH en el Río la Máquina, Ubicado en el Municipio de Diriamba.

Presenta un estudio de considerando la oferta eléctrica, el análisis de los precios actuales y futuros, la participación de la PCH en el mercado para finalizar con el plan estratégico de comercialización

Physical Education Classes as a Precursor to the Mediterranean Diet and the Practice of Physical Activity

Physical activity and a healthy, balanced diet are remaining unresolved issues among young people. According to the World Health Organization, young people do not get enough exercise during the week, and physical education classes are the best way to promote healthy habits. This study aims to analyze how the role of the teacher influences the frustration of psychological needs, coping strategies, motivation, and the adoption of healthy eating habits through the Mediterranean diet and the regular practice of physical activity. The study involved 1031 boys and 910 girls between the ages of 13 and 18. To explain the relationships between the different variables included in this study, a model of structural equations has been developed. The results showed that autonomy support negatively predicted the frustration of four psychological needs. The failure to meet four psychological needs negatively predicted resilience. Likewise, resilience positively predicted autonomous motivation, and this positively predicted the Mediterranean diet and the practice of physical activity. Thus, the results obtained in the present study are in line with those of various studies wherein physical education classes were seen to help consolidate healthy living habits

Analysis of the correlation between deformation and temperature in a concrete dam

Deformational control of structures has its greatest exponent in large dams monitoring, which, depending on their structural typology, can be subjected to movements generally based on both the pressure that they upport and the temperature.The designer usually calculates the theoretical displacements that the dam will suffer onsidering the hydrostatic thrust and the temperature, but it is also true that these displacements are theoretical and they do not often fit to the real movements, due to the uncertainties that arise during the onstruction of any dam and make the final structure have changes which can be more or less significant with respect to the originally projected one. However, it is worth mentioning that they are usually lower than those theoretically calculated. The present research work focuses on a potential correlation and the subsequent determination of an mpirical model that allows calculating the deformation by means of a polynomial fit, working on the basis of temperature observations held over 14 years. This empirical model is contrasted and validated with the observations taken during the following year, and although it is only valid for the dam where the test has been made (“La Cohilla” Dam), the methodology is suitable for any other structure

Determination of an empirical model for calculating the strain of a dam in terms of hydrostatic thrust

The deformational control of structures has its greatest exponent in the control of large dams, which depending on structural typology, can be subjected to movement generally based on the pressure that it suffers. The designer usually calculates the theoretical displacements that the dam must suffer depending on the ydrostatic pressure, function of the thrust bearing, but it is also true that this calculation is theoretical and it is not usually adjusted to the real movements, due to the uncertainties that arise in the construction of any dam and make the original project have more or less significant changes in the final construction. In favour of the builder, it must be said that the actual displacements are usually lower than the theoretical ones. The present research focuses on the determination of an empirical model that allows calculating the deformation based on practical observations of a direct pendulum over 14 years, which determines the isplacement and the pressure experienced by the dam represented by the height of water contained, by means of a polynomial adjustment. This empirical model is tested and then validated with observations over the ollowing year and, although it is only valid for the dam where the trial (La Cohilla Dam) is made, the ethodology is applicable to any other structure