An alternative approach for robot localization inside pipes using RF spatial fadings

Accurate robot localization represents a challenge inside pipes due to the particular conditions that characterize this type of environment. Outdoor techniques (GPS in particular) do not work at all inside metal pipes, while traditional indoor localization methods based on camera or laser sensors do not perform well mainly due to a lack of external illumination and distinctive features along pipes. Moreover, humidity and slippery surfaces make wheel odometry unreliable. In this paper, we estimate the localization of a robot along a pipe with an alternative Radio Frequency (RF) approach. We first analyze wireless propagation in metallic pipes and propose a series of setups that allow us to obtain periodic RF spatial fadings (a sort of standing wave periodic pattern), together with the influence of the antenna position and orientation over these fadings. Subsequently, we propose a discrete RF odometry-like method, by means of counting the fadings while traversing them. The transversal fading analysis (number of antennas and cross-section position) makes it possible to increase the resolution of this method. Lastly, the model of the signal is used in a continuous approach serving as an RF map. The proposed localization methods outperform our previous contributions in terms of resolution, accuracy, reliability and robustness. Experimental results demonstrate the effectiveness of the RF-based strategy without the need for a previously known map of the scenario or any substantial modification of the existing infrastructure

Robot Localization in Tunnels: Combining Discrete Features in a Pose Graph Framework; 35214292

Robot localization inside tunnels is a challenging task due to the special conditions of these environments. The GPS-denied nature of these scenarios, coupled with the low visibility, slippery and irregular surfaces, and lack of distinguishable visual and structural features, make traditional robotics methods based on cameras, lasers, or wheel encoders unreliable. Fortunately, tunnels provide other types of valuable information that can be used for localization purposes. On the one hand, radio frequency signal propagation in these types of scenarios shows a predictable periodic structure (periodic fadings) under certain settings, and on the other hand, tunnels present structural characteristics (e.g., galleries, emergency shelters) that must comply with safety regulations. The solution presented in this paper consists of detecting both types of features to be introduced as discrete sources of information in an alternative graph-based localization approach. The results obtained from experiments conducted in a real tunnel demonstrate the validity and suitability of the proposed system for inspection applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

A robotized dumper for debris removal in tunnels under construction

Tunnels in construction exhibit many challenges for automation. In this work we address the robotization of a conventional dumper for debris removal during the construction of tunnels, in the framework of a technological transfer project. The goal is to convert a dumper into an autonomous vehicle capable of planning, navigate and localize itself. Planning and navigation techniques have been adapted to the special kinodynamic characteristics of the vehicle. The difficulties for having a precise continuous localization in this kind of scenarios, due to the irregularities of the terrain, the changing illumination and the own scenario, have driven to develop hybrid localization techniques to integrate continuous and discrete information, coming from the navigation sensors, some semantic geometric features, and the signal strength propagation in tunnel scenarios. Simulation and real-world experiments are described, and some preliminary results are discussed

Ingesta de macronutrientes y prevalencia de malnutrición por exceso en escolares de 5o y 6o básico de distinto nivel socioeconómico de la región metropolitana

Obesity in childhood has become an important publie health problem in Chile. Objetive: to study macronutrient intake and nutritional status in school-age children attending5th andóth grade inprimary schoolsfrom different socioeconomic status located in 6 counties in Santiago, Chile. Methods: A total of 1,732 children between 9 and 12 years oldjrom both sexes were studied. Anthropometric evaluation included weight, height, and tricipital and subescapular thickness. Macronutrient intake was determined using a 24-hours recall survey. Socioeconomic status was estimated using the ESOMAR survey. Results: In this sample overweight and obesity prevalence reached 40%. Prevalence was higher in boys and in the lower socio-economic groups. A higher consumption ofproteins andfat wasfound in the wealthier groups, while a higher intake of carbohydrates was present in the poorer ones. Comparison with the daily recommended allowancesfound that both males andfemales hada 75% ofadequacy of all ofmacronutrients with the exception offiber. Conclusión: The study revealeda highprevalence ofmalnutrition in both sexes with a better nutrition standard among children in higher socioeconomic status.El sobrepeso y la obesidad infantil se han transformado en un importante problema en salud pública. Objetivo: evaluar la ingesta de macronutrientes y determinar la prevalencia de malnutrición en escolares de 5° y 6o año básico de distintos niveles socioeconómicos de 6 comunas de la Región Metropolitana. Sujetos y método: se evaluaron 1732 niños de ambos sexos de 9 a 12 años de edad. La evaluación antropométrica incluyo peso, talla, pliegue tricipital y subescapular. La ingesta de macronutrientes se evaluó mediante la aplicación de una encuesta recordatorio de 24 hrs; el nivel socioeconómico se evaluó mediante la aplicación la encuesta ESOMAR. Resultados: la prevalencia de malnutrición por exceso fue de 40%, siendo más importante en hombres de los estratos socioeconómicos de menores ingresos. Encontramos un mayor consumo de proteínas y grasas totales en el nivel socioeconómico más alto, mientras que el nivel de menores ingresos tuvo una mayor ingesta de carbohidratos. Tanto hombres como mujeres presentaron una adecuación superior al 75% en todos los macronutrientes con excepción de la fibra. Conclusión: El estudio arrojó una elevada prevalencia de malnutrición por exceso en ambos sexos con un mejor patrón de alimentación en los niños de nivel socioeconómico alto

Magnetic characterization of Fe, Ni, Co nanoparticles dispersed in phyllosilicate type silicon oxide

International audienceWe present the magnetic properties of silica-supported metal (Fe,catalyst) nanoparticles synthesized by precipitation of metal nitrate in ammonia-based medium. Our goal is the study of possible metal-support interactions in the nanoporous catalyst. The temperature dependence of the magnetization for all samples display spin-glass like behavior below c.a. 11-12 K, with clear Curie-Weiss dependence in the high-temperature regime. Spin-glass-like behavior was inferred from dynamic AC susceptibility data after analyzing the frequency-dependence of the in-phase component χ'(f) by the expression W = ΔTf/[Tf Δlog(f)] = 3.0 × 10−3. We found that the magnetic behavior of the catalyst is drastically affected by the existence of interactions between the metal and the support

When nothing is what it seems. A Digital Marketing Research Agenda

Digital breakthroughs continue to challenge prevailing understandings of markets and marketing practices, bringing exciting opportunities to reimagine our offerings. Looking through the lens of digital surrealism, we identify key trends emerging in the field: (1) Is AR (Augmented Reality) for real?; (2) There is no better PR than GDPR (General Data Protection Regulation); (3) A persona is not a persona; (4) Min(e)d your language, and; (4 ¾) Raise your voice. Maybe. Based on these trends we develop an agenda for future research that enables the realization of the opportunities that the digital space offers

Utilización del suero de queso en combinación con harina de arroz restringida para cerdos en crecimiento y acabado en pastoreo.

Arroz-Oryza sativ

Multiband optical variability of the blazar OJ 287 during its outbursts in 2015 -- 2016

We present recent optical photometric observations of the blazar OJ 287 taken during September 2015 -- May 2016. Our intense observations of the blazar started in November 2015 and continued until May 2016 and included detection of the large optical outburst in December 2016 that was predicted using the binary black hole model for OJ 287. For our observing campaign, we used a total of 9 ground based optical telescopes of which one is in Japan, one is in India, three are in Bulgaria, one is in Serbia, one is in Georgia, and two are in the USA. These observations were carried out in 102 nights with a total of ~ 1000 image frames in BVRI bands, though the majority were in the R band. We detected a second comparably strong flare in March 2016. In addition, we investigated multi-band flux variations, colour variations, and spectral changes in the blazar on diverse timescales as they are useful in understanding the emission mechanisms. We briefly discuss the possible physical mechanisms most likely responsible for the observed flux, colour and spectral variability.Comment: 11 pages, 6 figures, 4 tables; Accepted for publication in MNRA