347 research outputs found

    Simultaneous exercise recognition and evaluation in prescribed routines: Approach to virtual coaches

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    Home-based physical therapies are effective if the prescribed exercises are correctly executed and patients adhere to these routines. This is specially important for older adults who can easily forget the guidelines from therapists. Inertial Measurement Units (IMUs) are commonly used for tracking exercise execution giving information of patients' motion data. In this work, we propose the use of Machine Learning techniques to recognize which exercise is being carried out and to assess if the recognized exercise is properly executed by using data from four IMUs placed on the person limbs. To the best of our knowledge, both tasks have never been addressed together as a unique complex task before. However, their combination is needed for the complete characterization of the performance of physical therapies. We evaluate the performance of six machine learning classifiers in three contexts: recognition and evaluation in a single classifier, recognition of correct exercises, excluding the wrongly performed exercises, and a two-stage approach that first recognizes the exercise and then evaluates it. We apply our proposal to a set of exercises of the upper-and lower-limbs designed for maintaining elderly people health status. To do so, the motion of 30volunteers were monitored with 4 IMUs. We obtain accuracies of 88.4% and the 91.4% in the two initial scenarios. In the third one, the recognition provides an accuracy of 96.2%, whereas the exercise evaluation varies between 93.6% and 100%. This work proves the feasibility of IMUs for a complete monitoring of physical therapies in which we can get information of which exercise is being performed and its quality, as a basis for designing virtual coaches.Spanish Ministry of Science, In-novation and Universitie

    Design of Fear and Anxiety of COVID-19 Assessment Tool in Spanish Adult Population

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    The aim of this study was to develop a specific scale to measure anxiety and fear levels in the general Spanish population. For this, a transcultural adaptation to Spanish of the fear of coronavirus disease 2019 (COVID-19) scale, in its original version of 10 items, was carried out. Then, the Anxiety and Fear of COVID-19 Assessment Scale (AMICO, for its acronym in Spanish) was designed by translating the tool and Delphi technique into three rounds. Ten experts participated voluntarily, and inter-observer match rates and the reliability study of the designed scale were calculated. A pilot study was carried out with the final version of the scale for the validity and reliability study. The instrument did not raise problems in semantic and cultural terms during the first and second rounds of the translation process, with an overall weighted Kappa value of 0.9. In the third round, eight new items were designed and consensual, obtaining a weighted overall value of 0.89. The pilot study sample was made up of 445 subjects, of which 60.3% were women with a mean age of 46.2 years. The final version consisted of 16 items, 2 factors, and a Cronbach’s alpha value of 0.92. The AMICO scale was developed to assess the level of anxiety and fear of COVID-19 and proved to be valid and reliable for its use in the adult Spanish population.Junta de Andalucía PI 036/2

    Raman spectrum of group IV nanowires: influence of temperature

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    Group IV semiconductor nanowires are characterized by Raman spectroscopy. The results are analyzed in terms of the heating induced by the laser beam on the nanowires. By solving the heat transport equation one can simulate the temperature reached by the NWs under the exposure to a laser beam. The results are illustrated with Si and Si1-xGex nanowires. Both bundles of nanowires and individual nanowires are studied. The main experimental conditions contributing to the nanowire heating are discusse

    Advanced monitoring of rail breakage in double-track railway lines by means of PCA techniques

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    This work describes a classifier designed to identify rail breakages in double-track railway lines, completing the electronic equipment carried out by authors. The main objective of this proposal is to guarantee the integrity of tracks before the railway traffic starts working. In addition, it facilitates maintenance tasks providing information about possible breakages. The detection of breakages is based on the analysis of eight currents provided by the electronic equipment, one per rail, at the ends of the section (emitting and receiving nodes). The imbalance that occurs among the value of these currents implies that there is at least a breakage in the track section under analysis. This analysis is conducted according to three phases. The first one identifies whether there is a breakage, and, in that case, the damaged track is identified. The second phase provides information about which rail is broken (internal, external or both of them) in the previously identified track. Finally, if there is only one breakage, the third phase estimates its most likely zone along the track section. This situation is considered as a classification problem, and solved by means of the Principal Component Analysis technique. This means that a significant number of measurements is required for every breakage pattern (types of breakages) to be considered. Due to the difficulty of having real data, the proposal has been validated using an 8km-long double-track hardware simulator specially designed by the authors, with specific localizations for breakages

    Tratamiento con ozono de lejĂ­as residuales del aderezo de aceitunas negras

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    Black olive wastewaters degradation by ozone has been studied. Organic matter removal was followed by means of global parameters like chemical oxygen demand, aromaticity and polyphenolic compounds. The influence of modified operating variables (temperature and pH) on evolution of this parameters was analized. Ozone consumption, ozone absorption rate and ozonation yield was also determined. Finally, a kinetic study was performed to determine the apparent kinetic constants for the chemical oxygen demand and aromaticity reductions.Se ha estudiado la depuraciĂłn de las lejĂ­as residuales procedentes del aderezo de aceitunas negras mediante ozono. La reducciĂłn de la materia orgĂĄnica contaminante fue seguida por medio de parĂĄmetros globales como son la demanda quĂ­mica de oxĂ­geno, la aromaticidad y los compuestos polifenĂłlicos. En primer lugar, se ha analizado la influencia de las variables de operaciĂłn modificadas (temperatura y pH) sobre la evoluciĂłn de aquellos parĂĄmetros. A continuaciĂłn, se ha determinado el consumo de ozono, la velocidad de absorciĂłn de ozono y el rendimiento de ozonizaciĂłn. Por Ășltimo, se ha realizado un estudio cinĂ©tico con el objeto de determinar la constante cinĂ©tica para la reducciĂłn de la demanda quĂ­mica de oxĂ­geno y de la aromaticidad

    El territorio de la frontera luso-andaluza. Una geometrĂ­a variable

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    La frontera hispano-portuguesa que discurre entre la región del Algarve, el Baixo Alentejo y la provincia de Huelva ha dividido comunidades de estructuras territoriales similares, a las que, acorde a la desactivación de la frontera, se les ha aplicado políticas territoriales y de cooperación que en términos generales no han servido ni para su desarrollo ni para el mantenimiento de su población. En este trabajo se pretende, principalmente, caracterizar los elementos estructurantes de este espacio fronteriz

    Biomass valorization by using a sequence of acid hydrolysis and pyrolysis processes. Application to Leucaena leucocephala

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    Among main ways to provide an environmentally friendly energy and platform chemicals are the lignocellulosic conversion processes. The proper execution of this way will depend on the correct selection of lignocellulosic materials. A compelling plant is Leucaena leucocephala because its great variety of uses, its high biomass production and its leguminous nature. In this study, acid hydrolysis (130-170°C and 0.5-2% H2SO4, to extract valuable hemicelluloses) as pretreatment and pyrolysis of the solid residue (to get a gaseous fuel) as treatment have been used in its valorization. A laboratory-scale reactor was used for the pyrolysis experiments (550ÂșC, N2) for both Leucaena leucocephala, as raw material, and the solid residues after hydrolysis process and raw material. The amounts of CO, CO2 and H2 found in the raw material are similar to those found in the solids obtained after the different studied hydrolysis conditions. Moreover, the thermal behavior of studied solids has been studied by thermogravimetric analysis under nitrogen atmosphere at different heating rates (5, 10, 15 and 20 ÂșC min-1). Activation energy for all samples has been obtained by the Flynn-Wall-Ozawa method. The optimum value, in which a high relationship between recoverable hemicelluloses fraction and H2 concentration is found, under medium hydrolysis temperature (150ÂșC) has been obtained and was independent of the amount of acid added to the hydrolysis process

    Maximizing furfural concentration from wheat straw and Eucalyptus globulus by nonisothermal autohydrolysis

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    The autohydrolysis process as a method for selective extraction of hemicelluloses and conversion to furfural was proposed for lignocellulosic raw materials. Samples of wheat straw (WS) and Eucalyptus globulus (EG) were subjected to nonisothermal autohydrolysis, defined by temperature 180–240°C. Within a biorefinery scheme for the selected materials, the aim of this study is both (a) to optimize furfural processing technology to enable higher yields and improved productivity from EG and WS by autohydrolysis and (b) to not excessively degrade the remaining polymeric constituents (glucan) in solid to facilitate a potential later use. Differences in the rate of the dehydration reaction of xylose to furfural have been observed, and it is faster in the case of WS with respect to that observed for eucalyptus. In that form, 4.25 g/100 g raw material (26% of the initial xylan in WS) could be found at 220°C, and an increase in the temperature (240°C) yielded 4.54 g/100 g raw material, 28% of the initial xylan. In EG, the increase in the hydrolysis temperature (240°C) yielded liquor with higher contents of furfural (4.45 g/100 g raw material, 25% of the initial xylan) and acetic acid (4.49 g/100 g raw material) and smaller contents of arabinose and xylan. In WS, a faster dehydration is found

    Integral valorization of tagasaste (Chamaecytisus proliferus) under thermochemical processes

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    The generation of compounds derived from lignocellulosic biomass fractionation has a boost in recent years. An interesting plant could be tagasaste (Chamaecytisus proliferus) due to its high biomass production and its leguminous nature. A sequence of acid hydrolysis, as pretreatment, and pyrolysis of the solid residue, as treatment, has been used in its valorization. An experimental design (H2SO4 acid concentration 0.5–2%, temperature 130–170 °C, and time 30– 60 min) has been used to study the hydrolysis process. In the proposed acid hydrolysis process, under 170 °C as operational temperature, 0.5% of H2SO4 and 30 min for the operation time, 91.75% of the initial xylose have been extracted. The thermal behavior of both tagasaste trunks-large branches and some solid residues after hydrolysis (furthest and center points in the experimental design) process and raw material have been studied by thermogravimetric analysis under nitrogen atmosphere at different heating rates (5, 10, 15, and 20 °C min−1). The thermal degradation of the studied materials is influenced by its initial composition. Then, the higher reactivity of hemicelluloses can accelerate the pyrolysis degradation reaction. However, higher cellulose content implies lower activation energy in pyrolysis process
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