A Path Planning Algorithm for a Dynamic Environment Based on Proper Generalized Decomposition

[EN] A necessity in the design of a path planning algorithm is to account for the environment. If the movement of the mobile robot is through a dynamic environment, the algorithm needs to include the main constraint: real-time collision avoidance. This kind of problem has been studied by different researchers suggesting different techniques to solve the problem of how to design a trajectory of a mobile robot avoiding collisions with dynamic obstacles. One of these algorithms is the artificial potential field (APF), proposed by O. Khatib in 1986, where a set of an artificial potential field is generated to attract the mobile robot to the goal and to repel the obstacles. This is one of the best options to obtain the trajectory of a mobile robot in real-time (RT). However, the main disadvantage is the presence of deadlocks. The mobile robot can be trapped in one of the local minima. In 1988, J.F. Canny suggested an alternative solution using harmonic functions satisfying the Laplace partial differential equation. When this article appeared, it was nearly impossible to apply this algorithm to RT applications. Years later a novel technique called proper generalized decomposition (PGD) appeared to solve partial differential equations, including parameters, the main appeal being that the solution is obtained once in life, including all the possible parameters. Our previous work, published in 2018, was the first approach to study the possibility of applying the PGD to designing a path planning alternative to the algorithms that nowadays exist. The target of this work is to improve our first approach while including dynamic obstacles as extra parameters.This research was funded by the GVA/2019/124 grant from Generalitat Valenciana and by the RTI2018-093521-B-C32 grant from the Ministerio de Ciencia, Innovacion y Universidades.Falcó, A.; Hilario, L.; Montés, N.; Mora, MC.; Nadal, E. (2020). A Path Planning Algorithm for a Dynamic Environment Based on Proper Generalized Decomposition. Mathematics. 8(12):1-11. https://doi.org/10.3390/math8122245S111812Gonzalez, D., Perez, J., Milanes, V., & Nashashibi, F. (2016). A Review of Motion Planning Techniques for Automated Vehicles. IEEE Transactions on Intelligent Transportation Systems, 17(4), 1135-1145. doi:10.1109/tits.2015.2498841Rimon, E., & Koditschek, D. E. (1992). Exact robot navigation using artificial potential functions. IEEE Transactions on Robotics and Automation, 8(5), 501-518. doi:10.1109/70.163777Khatib, O. (1986). Real-Time Obstacle Avoidance for Manipulators and Mobile Robots. The International Journal of Robotics Research, 5(1), 90-98. doi:10.1177/027836498600500106Kim, J.-O., & Khosla, P. K. (1992). Real-time obstacle avoidance using harmonic potential functions. IEEE Transactions on Robotics and Automation, 8(3), 338-349. doi:10.1109/70.143352Connolly, C. I., & Grupen, R. A. (1993). The applications of harmonic functions to robotics. Journal of Robotic Systems, 10(7), 931-946. doi:10.1002/rob.4620100704Garrido, S., Moreno, L., Blanco, D., & Martín Monar, F. (2009). Robotic Motion Using Harmonic Functions and Finite Elements. Journal of Intelligent and Robotic Systems, 59(1), 57-73. doi:10.1007/s10846-009-9381-3Bai, X., Yan, W., Cao, M., & Xue, D. (2019). Distributed multi‐vehicle task assignment in a time‐invariant drift field with obstacles. IET Control Theory & Applications, 13(17), 2886-2893. doi:10.1049/iet-cta.2018.6125Bai, X., Yan, W., Ge, S. S., & Cao, M. (2018). An integrated multi-population genetic algorithm for multi-vehicle task assignment in a drift field. Information Sciences, 453, 227-238. doi:10.1016/j.ins.2018.04.044Falcó, A., & Nouy, A. (2011). Proper generalized decomposition for nonlinear convex problems in tensor Banach spaces. Numerische Mathematik, 121(3), 503-530. doi:10.1007/s00211-011-0437-5Chinesta, F., Leygue, A., Bordeu, F., Aguado, J. V., Cueto, E., Gonzalez, D., … Huerta, A. (2013). PGD-Based Computational Vademecum for Efficient Design, Optimization and Control. Archives of Computational Methods in Engineering, 20(1), 31-59. doi:10.1007/s11831-013-9080-xFalcó, A., Montés, N., Chinesta, F., Hilario, L., & Mora, M. C. (2018). On the Existence of a Progressive Variational Vademecum based on the Proper Generalized Decomposition for a Class of Elliptic Parameterized Problems. Journal of Computational and Applied Mathematics, 330, 1093-1107. doi:10.1016/j.cam.2017.08.007Domenech, L., Falcó, A., García, V., & Sánchez, F. (2016). Towards a 2.5D geometric model in mold filling simulation. Journal of Computational and Applied Mathematics, 291, 183-196. doi:10.1016/j.cam.2015.02.043Falcó, A., & Nouy, A. (2011). A Proper Generalized Decomposition for the solution of elliptic problems in abstract form by using a functional Eckart–Young approach. Journal of Mathematical Analysis and Applications, 376(2), 469-480. doi:10.1016/j.jmaa.2010.12.003Falcó, A., & Hackbusch, W. (2012). On Minimal Subspaces in Tensor Representations. Foundations of Computational Mathematics, 12(6), 765-803. doi:10.1007/s10208-012-9136-6Canuto, C., & Urban, K. (2005). Adaptive Optimization of Convex Functionals in Banach Spaces. SIAM Journal on Numerical Analysis, 42(5), 2043-2075. doi:10.1137/s0036142903429730Ammar, A., Chinesta, F., & Falcó, A. (2010). On the Convergence of a Greedy Rank-One Update Algorithm for a Class of Linear Systems. Archives of Computational Methods in Engineering, 17(4), 473-486. doi:10.1007/s11831-010-9048-

Ionic-liquid doped polymeric composite as passive colorimetric sensor for meat freshness as a use case

[EN] A composite membrane containing 1,2-naphthoquinone-4-sulfonic acid sodium salt (NQS) embedded in an ionic liquid (IL)- polydimethylsiloxane (PDMS)- tetraethyl orthosilicate (TEOS)- SiO2 nanoparticles (NPs) polymeric matrix is proposed. The selected IL was 1-methyl-3-octylimidazolium hexafluorophosphate (OMIM PF6). It is demonstrated that ILs chemical additives of PDMS influenced the sol-gel porosity. The sensor analytical performance for ammonia atmospheres has been tested as a function of sampling time (between 0.5 and 312 h), temperature (25 ◦C and 4 ◦C) and sampling volume (between 2L and 22 mL) by means of diffuse reflectance measurements and sensor photos, which can be registered and saved as images by a smartphone, which permit RGB measurements too. Flexible calibration was possible, adapting it to the sampling time, temperature and sampling volume needed for its application. Calibration linear slopes (mA vs ppmv) between 1.7 and 467 ppmv-1 were obtained for ammonia in function of the several studied conditions. Those slopes were between 48 and 91% higher than those achieved with sensors without ILs. The practical application of this sensing device was demonstrated for the analysis of meat packaging environments, being a potential cost-effective candidate for in situ meat freshness analysis. NQS provided selectivity in reference to other family compounds emitted from meat products, such as sulphides. After 10 days at 4 ◦C ammonia liberated by the assayed meat was 20 ± 4 μg/kg and 18 ± 3 μg/kg, quantified by using diffuse reflectance and %R measurements, respectively. Homogeneity of the ammonia atmosphere was tested by using two sensors placed in two different positions inside the packages

Assessing Emotional Distress in Adolescents: Psychometrics of the Spanish Version of the Social Emotional Distress Scale-Secondary

Background The Social Emotional Distress Scale-Secondary (SEDS-S) is a short measure designed for comprehensive school-based mental health screening, particularly for using very brief self-reported measures of well-being and distress. Whereas prior studies have shown validity and reliability evidence for the English version, there is a lack of literature about its psychometric properties for Spanish-speaking youths. Objective To examine the psychometric properties of the SEDS-S in a large sample of Spanish adolescents, providing evidence of its reliability, structure, convergent and discriminant validity, longitudinal and gender measurement invariance, and normative data. Methods Participants were 5550 adolescents aged 12–18 years old. Test–retest reliability was examined using Cronbach’s alpha and McDonald’s omega coefficients, and evidence for convergent and discriminant validity was measured using Pearson’s correlation. Confirmatory factor analysis (CFA) was used to examine structure validity, while multigroup and longitudinal measurement invariance analysis was conducted for longitudinal and gender latent structure stability. Results The CFA supported a unidimensional latent structure, which was also observed to be invariant between gender groups and over time. The scale showed evidence of reliability, with coefficients above .85. In addition, the SEDS-S score was positively related to measures assessing distress and negatively related to measures assessing well-being, thereby providing convergent/discriminant validity of the total scores. Conclusion This study provides the first evidence of the reliability and validity of the Spanish version of the SEDS-S for assessing emotional distress among adolescents, cross-sectionally and longitudinally. Furthermore, findings indicated that SEDS-S could be a suitable assessment tool for screening and program evaluation purposes at different contexts beyond the school setting

Comparativa morphology of the venom apparatus in some subfamilias of braconid wasps (Hymenoptera: Braconidae)*

ABSTRACT Venom apparatus morphology has been investigated in 23 species of 6 subfamilies of Braconidae: Braconinae, Doryctinae, Exothecinae, Rogadinae, Opiinae and Cheloninae. Several signiñcant characters are described and illustrated. Differences in the presence or absence of constrictions dividing the reservoir into a number of distinct regions, the number and position of the insertions of the venom gland ducts on the reservoir, the branching pattern of the venom glands, and in the evennes and distribution of the spiral thickenings of the reservoir and duct intima are discussed. Key words: Braconidae, venom apparatus, reservoir, venom glands, intima, morphology. RESUMEN Anatomía comparada del aparato del veneno en bracónidos (Hymenoptera: Braconidae). Se estudia la anatomía del aparato del veneno en 23 especies incluidas en 6 subfamilias de Braconidae: Braconinae, Doryctinae, Exothecinae, Rogadinae, Opiinae y Cheloninae. Se presentan y describen algunos caracteres como son la presencia o ausencia de constricciones en el reservorio, el número y posición de los filamentos glandulares en el reservorio, la ramificación de la glándula del veneno o el tipo y distribución de espiralamiento en la íntima del reservorio y de los conductos glandulares. Palabras clave: Braconidae, aparato del veneno, reservorio, glándula del veneno, íntima, anatomía

New silica based adsorbent material from rice straw and its in-flow application to nitrate reduction in waters: Process sustainability and scale-up possibilities

[EN] This paper shows a particular example to move to a sustainable circular economical process from valorization of rice straw ashes by developing a green synthesis for obtaining a useful sub-product. This strategy can palliate negative effects of the agriculture waste practices on the environment and also the obtained silica reduced nitrate content in waters. It is demonstrated that the silica synthesis developed at lab was scalable more than a hundred times with good results. Adsorption studies of nitrate in standards and real well waters at lab scale and scaling-up provided similar results. Adsorption values near to 15 mg/g for nitrate standards and 8.5 mg/g for well water were obtained until achieving the initial nitrate concentration. Experimental breakthrough curves fitted to Thomas model, which gave similar results for adsorption capacities. The adsorption capacity was checked with that obtained by a commercial resin, providing improved results. The method at large scale was compared with industrial traditional methods and green adsorbents.The authors are grateful to EU (EASME LIFE and CIP ECO-Innovation) LIBERNITRATE. LIFE 16 ENV/ES/000419; EU FEDER and the Gobierno de Espana MCIU-AEI (CTQ2017-90082-P) and the Generalitat Valenciana (PROMETEO 2020/078) and EU FEDER-Generalitat Valenciana (ID-FEDER/2018/049) for the financial support received. H. R. Robles-Jimarez expresses his grateful to EU-LIBERNITRATE. L. Sanjuan-Navarro expresses his gratitude for the FPU-grant (MCIU-AEI) .Robles-Jimarez, H.; Sanjuan-Navarro, L.; Jornet-Martínez, N.; Primaz, C.; Teruel-Juanes, R.; Molins-Legua, C.; Ribes-Greus, A.... (2022). New silica based adsorbent material from rice straw and its in-flow application to nitrate reduction in waters: Process sustainability and scale-up possibilities. Science of The Total Environment. 805:1-12. https://doi.org/10.1016/j.scitotenv.2021.15031711280

Evaluation of an Organic Waste Composting Device to Household Treatment

The performance of a plug-flow automated aerobic digester used with the compost of the Biodegradable Organic Waste (BOW) from a typical family at its generation rhythm was evaluated. During a 13 month assessment, 179.7 kg of BOW were treated and 106.7 kg of compost were obtained with a C:N ratio of 12 and an average concentration of N of about 2.72%. Additional tests enabled to assess the generation of stable and good quality compost according to the considered standards, suitable for using as organic fertilizer and other uses, such as biotreatments. The design, location and operational characteristics of the device have determined reduced leachate emissions, the absence of unpleasant odour generation and incidence of insects or other vectors, implying the viability of their use without affecting the user´s life quality. It could be an efficient alternative treatment for household BOW, from a technical, economic, energy, cultural and environmental point of view, easy to implement for users lacking in special training

Mytilus galloprovincialis Myticin C: A Chemotactic Molecule with Antiviral Activity and Immunoregulatory Properties

Previous research has shown that an antimicrobial peptide (AMP) of the myticin class C (Myt C) is the most abundantly expressed gene in cDNA and suppressive subtractive hybridization (SSH) libraries after immune stimulation of mussel Mytilus galloprovincialis. However, to date, the expression pattern, the antimicrobial activities and the immunomodulatory properties of the Myt C peptide have not been determined. In contrast, it is known that Myt C mRNA presents an unusual and high level of polymorphism of unidentified biological significance. Therefore, to provide a better understanding of the features of this interesting molecule, we have investigated its function using four different cloned and expressed variants of Myt C cDNA and polyclonal anti-Myt C sera. The in vivo results suggest that this AMP, mainly present in hemocytes, could be acting as an immune system modulator molecule because its overexpression was able to alter the expression of mussel immune-related genes (as the antimicrobial peptides Myticin B and Mytilin B, the C1q domain-containing protein MgC1q, and lysozyme). Moreover, the in vitro results indicate that Myt C peptides have antimicrobial and chemotactic properties. Their recombinant expression in a fish cell line conferred protection against two different fish viruses (enveloped and non-enveloped). Cell extracts from Myt C expressing fish cells were also able to attract hemocytes. All together, these results suggest that Myt C should be considered not only as an AMP but also as the first chemokine/cytokine-like molecule identified in bivalves and one of the few examples in all of the invertebrates

Real-Time Path Planning Based on Harmonic Functions under a Proper Generalized Decomposition-Based Framework

This paper presents a real-time global path planning method for mobile robots using harmonic functions, such as the Poisson equation, based on the Proper Generalized Decomposition (PGD) of these functions. The main property of the proposed technique is that the computational cost is negligible in real-time, even if the robot is disturbed or the goal is changed. The main idea of the method is the off-line generation, for a given environment, of the whole set of paths from any start and goal configurations of a mobile robot, namely the computational vademecum, derived from a harmonic potential field in order to use it on-line for decision-making purposes. Up until now, the resolution of the Laplace or Poisson equations has been based on traditional numerical techniques unfeasible for real-time calculation. This drawback has prevented the extensive use of harmonic functions in autonomous navigation, despite their powerful properties. The numerical technique that reverses this situation is the Proper Generalized Decomposition. To demonstrate and validate the properties of the PGD-vademecum in a potential-guided path planning framework, both real and simulated implementations have been developed. Simulated scenarios, such as an L-Shaped corridor and a benchmark bug trap, are used, and a real navigation of a LEGO®MINDSTORMS robot running in static environments with variable start and goal configurations is shown. This device has been selected due to its computational and memory-restricted capabilities, and it is a good example of how its properties could help the development of social robots

Contaminants químics: estudi de dieta total a Catalunya, 2000-2002

Estudi de dieta total; Contaminants químics; Seguretat alimentàriaTotal diet study; Chemical pollutants; Food safetyEstudio de dieta total; Contaminantes químicos; Seguridad alimentariaL’estudi intenta contribuir a conèixer millor alguns riscos per a la salut associats a la contaminació química dels aliments. A més, ho fa tenint en compte els hàbits alimentaris de Catalunya, amb la qual cosa té el valor afegit de proporcionar-nos eines que ens poden ajudar a dissenyar mesures que contribueixin a la millora de la salutde la nostra població.El estudio intenta contribuir a conocer mejor algunos riesgos para la salud asociados a la contaminación química de los alimentos. Además, lo hace teniendo en cuenta los hábitos alimentarios de Cataluña, con lo cual tiene el valor añadido de proporcionarnos herramientas que nos pueden ayudar a diseñar medidas que contribuyan a la mejora de la salud de nuestra población.The study seeks to contribute to better understand certain health risks associated with chemical contamination of food. In addition, it takes into account the food habits in Catalonia, which has the added value of providing tools that can help us to design measures that contribute to improving the health of our population

Tensor completion in hierarchical tensor representations

Compressed sensing extends from the recovery of sparse vectors from undersampled measurements via efficient algorithms to the recovery of matrices of low rank from incomplete information. Here we consider a further extension to the reconstruction of tensors of low multi-linear rank in recently introduced hierarchical tensor formats from a small number of measurements. Hierarchical tensors are a flexible generalization of the well-known Tucker representation, which have the advantage that the number of degrees of freedom of a low rank tensor does not scale exponentially with the order of the tensor. While corresponding tensor decompositions can be computed efficiently via successive applications of (matrix) singular value decompositions, some important properties of the singular value decomposition do not extend from the matrix to the tensor case. This results in major computational and theoretical difficulties in designing and analyzing algorithms for low rank tensor recovery. For instance, a canonical analogue of the tensor nuclear norm is NP-hard to compute in general, which is in stark contrast to the matrix case. In this book chapter we consider versions of iterative hard thresholding schemes adapted to hierarchical tensor formats. A variant builds on methods from Riemannian optimization and uses a retraction mapping from the tangent space of the manifold of low rank tensors back to this manifold. We provide first partial convergence results based on a tensor version of the restricted isometry property (TRIP) of the measurement map. Moreover, an estimate of the number of measurements is provided that ensures the TRIP of a given tensor rank with high probability for Gaussian measurement maps.Comment: revised version, to be published in Compressed Sensing and Its Applications (edited by H. Boche, R. Calderbank, G. Kutyniok, J. Vybiral