Visibility in underwater robotics: Benchmarking and single image dehazing

Dealing with underwater visibility is one of the most important challenges in autonomous underwater robotics. The light transmission in the water medium degrades images making the interpretation of the scene difficult and consequently compromising the whole intervention. This thesis contributes by analysing the impact of the underwater image degradation in commonly used vision algorithms through benchmarking. An online framework for underwater research that makes possible to analyse results under different conditions is presented. Finally, motivated by the results of experimentation with the developed framework, a deep learning solution is proposed capable of dehazing a degraded image in real time restoring the original colors of the image.Una de las dificultades más grandes de la robótica autónoma submarina es lidiar con la falta de visibilidad en imágenes submarinas. La transmisión de la luz en el agua degrada las imágenes dificultando el reconocimiento de objetos y en consecuencia la intervención. Ésta tesis se centra en el análisis del impacto de la degradación de las imágenes submarinas en algoritmos de visión a través de benchmarking, desarrollando un entorno de trabajo en la nube que permite analizar los resultados bajo diferentes condiciones. Teniendo en cuenta los resultados obtenidos con este entorno, se proponen métodos basados en técnicas de aprendizaje profundo para mitigar el impacto de la degradación de las imágenes en tiempo real introduciendo un paso previo que permita recuperar los colores originales

Ecuaciones de estado y estructura de estrellas de neutrones

Las estrellas de neutrones son objetos formados en el colapso de estrellas masivas, pero no suficiente masivas como para colapsar en agujeros negros. Una estrella de neutrones típica encierra una masa como la de nuestro Sol en un radio de varios kilómetros, por lo que son objetos extremadamente compactos (con radio superior a, pero del orden de, 2GM/c2) y deben por tanto ser estudiados utilizando los resultados de la relatividad general frente a la gravedad newtoniana. La densidad de la materia en una estrella de neutrones varía desde densidades cotidianas en la superficie hasta densidades superiores a la densidad de los núcleos atómicos en su centro. Esto hace que el estudio de la materia en su interior esté gobernado por campos de la física como la mecánica estadística, física nuclear y mecánica cuántica relativista, entre otros. La participación de tantas ramas de la física, tanto moderna como tradicional, hace que el estudio del interior de las estrellas de neutrones sea, junto con sus observaciones astronómicas, de un gran valor teórico. Esto es particularmente cierto para la física que trata con materia a altas densidades, difícil de estudiar experimentalmente en laboratorios aquí en la Tierra. Este trabajo se ha planteado como una introducción al estudio de modelos de estrellas de neutrones, con un nivel apropiado para estudiantes universitarios de física que tengan un interés hacia este campo pero se vean intimidados por la extensa, densa, y generalmente demasiado especializada bibliografía que cubre estos tópicos. Con este fin, se ha hecho mucho hincapié en recopilar la física que lleva a los resultados de interés desde un nivel muy fundamental para recordar conceptos clave. También se introducen en su contexto algunos términos típicos de la jerga de este campo de estudio, cuyo conocimiento es necesario para leer textos más avanzados. Acompañamos la teoría con resultados numéricos obtenidos con un código en Python 3. El código está disponible en los anexos, así como algunos comentarios sobre las particularidades de los métodos numéricos utilizados

Efficient integral equation formulation for inductive waveguide components with posts touching the waveguide walls

In this paper a surface integral equation technique is employed for the analysis of inductive waveguide problems containing metallic or dielectric objects of arbitrary shape, focusing on the case where these objects are connected to the waveguide walls. Using the extinction theorem, the main problem is split into two problems. In the first one the parallel plate waveguide Green’s functions are used. Because of the choice of these functions, the side of the object touching the waveguide wall is not considered for discretization in a method of moments analysis. The second problem is applied inside the dielectric object, and uses the free space Green’s functions. It is shown that an additional spatial image is needed to impose the proper boundary conditions for the fields on the side touching the waveguide wall in the original problem. Results show the importance of including this additional image in the formulation for the correct behavior of the fields. With the proposed technique, the paper explores some alternatives for designing specific filter responses using dielectric posts inside cavity filters. Comparisons with a commercial finite elements tool demonstrate the accuracy of the proposed integral equation formulation.This work has been developed with support from the Spanish National Project (CICYT) with Ref TEC2004-04313-C02-02/TCM, and the Regional Seneca Project with Ref 02972/PI/05

Recovering Depth from Still Images for Underwater Dehazing Using Deep Learning

Estimating depth from a single image is a challenging problem, but it is also interestingdue to the large amount of applications, such as underwater image dehazing. In this paper, a newperspective is provided; by taking advantage of the underwater haze that may provide a strong cue tothe depth of the scene, a neural network can be used to estimate it. Using this approach the depthmapcan be used in a dehazing method to enhance the image and recover original colors, offering abetter input to image recognition algorithms and, thus, improving the robot performance duringvision-based tasks such as object detection and characterization of the seafloor. Experiments areconducted on different datasets that cover a wide variety of textures and conditions, while using adense stereo depthmap as ground truth for training, validation and testing. The results show that theneural network outperforms other alternatives, such as the dark channel prior methods and it is ableto accurately estimate depth from a single image after a training stage with depth information

Mubody, an astrodynamics open-source Python library focused on libration points

Mubody is an astrodynamics open-source Python library focused on the libration points. Such points result from the equilibrium of the gravitational forces between two massive bodies as the Sun and Earth, for example. The library is mainly intended for the generation of orbits in these regions, which is not a straightforward process, specially if perturbations are considered. Currently, the library allows to generate Lissajous orbits in the second Lagrange point of the Sun-Earth system under the influence of perturbations such as the Earth orbit eccentricity. The next milestone, as a result of a master student work, is the incorporation of Halo orbits and the expansion to all three collinear libration points from any two massive bodies of the Solar System. This tool has been developed as part of a PhD, motivated by the need of performing mission analysis in libration point regions. Nevertheless, since its creation it has also proven to be an excellent academic tool for both enhancing the library itself and using its results for further studies (collision risk, thermal analysis, formation flight control, etc). As a result, the tool has rapidly evolved, building onto the knowledge and experience that the students gather while working on their academic projects (bachelor’s degree dissertations, master theses, subjects, internships). The participation on the library development provides students with experience in orbital mechanics, software design, version control and it compels them to ensure that their work can be readily used by others as it is properly documented. The project is hosted in GitLab under a MIT licenc

Sexually Selected Egg Coloration in Spotless Starlings

It has been recently proposed that the blue-green coloration in eggs of many avian species may constitute a sexually selected female signal. Blue-green color intensity would reflect the physiological condition of females, and hence it might also affect the allocation of male parental care. In this study, we use three different experimental approaches to explore the importance of sexual selection on blue-green egg coloration of spotless starling (Sturnus unicolor) eggs. First, experimental deterioration of female body condition (by means of wing feather removal) negatively affected the intensity of blue-green egg coloration. Second, blue-green color intensity of artificial model eggs had a significant positive influence on paternal feeding effort. Finally, we found a negative relationship between the effect of experimental food supply on nestling immunocompetence and the intensity of blue-green coloration of eggs, suggesting that egg color predicts nutritional conditions that nestlings will experience during development. All these results taken together strongly support a role of sexual selection in the blue-green coloration of spotless starling eggs.This research was funded by the Spanish Ministry of Education and Science and the Fondo Europeo de Desarrollo Regional (FEDER; CGL2004-01777/BOS).Peer reviewe

Sampling with transects inside archaeological sites. A rapid action protocol based on statistical analysis of diagnostic collections and quantitative records

The paper proposes a two stage-sampling strategy for surface surveys. The suggested approach has two stages. First, an intensive survey is undertaken across linear transects, georeferencing the position of each item, and then supplementary diagnostic artefacts between the linear transects are collected. The main objective of the paper is to save time in the first stage of fieldwork. The key claim is that this approach would provide a representative sample of the surface scatter using just one selected transect. The proposed method is applied to the examination of two sites in the Municipium Flavium Baesuccitanum, a Roman municipality from the 1st century CE, located in the upper Guadalquivir valley, in the south of Spain, where a total survey was previously carried out. To assess the reliability of this approach, a simulation study was conducted at these two sites, selected by intensive sampling. These sites were chosen because they are real cases with different singularities, which facilitates analysis of how the proposed protocol would behave in different scenarios. In both cases, the statistical results confirm the plausibility of the hypothesis of similarity between the distributions of the whole site and the candidate transect.Research Group PAIDI-HUM357 (GIPAJ

L’occupation “Benahoarita” du Barranco de los Gomeros (Tijarafe) et le peuplement aborigène de l’île de La Palma (Îles Canaries)

Le peuplement aborigène des îles Canaries est un des thèmes prédominants de la recherche archéologique de l’archipel. Dans le cas de l’île de La Palma, les différentes datations C14 sont toutes postérieures au Ier siècle av J.C. La tendance générale est, cependant, de situer le peuplement de l’île entre le IIe et le Ier siècle av J.C. Le processus de peuplement et la colonisation sont, traditionnellement, interprétés comme s’étant réalisés d’est en ouest.Les premiers résultats des travaux dans la Cueva de las Mejoras (barranco de los Gomeros, nord-ouest de l’île), sur la base d’une chronologie relative offerte par l’étude des tessons de poteries, pointeraient vers une occupation simultanée de tout le territoire insulaire. Les investigations entreprises dans les grottes du barranco de los Gomeros (Tijarafe) sont, donc, essentielles pour appréhender le peuplement de l’île de La Palma

Fitting primitive shapes in point clouds: a practical approach to improve autonomous underwater grasp specification of unknown objects

This article presents research on the subject of autonomous underwater robot manipulation. Ongoing research in underwater robotics intends to increase the autonomy of intervention operations that require physical interaction in order to achieve social benefits in fields such as archaeology or biology that cannot afford the expenses of costly underwater operations using remote operated vehicles. Autonomous grasping is still a very challenging skill, especially in underwater environments, with highly unstructured scenarios, limited availability of sensors and adverse conditions that affect the robot perception and control systems. To tackle these issues, we propose the use of vision and segmentation techniques that aim to improve the specification of grasping operations on underwater primitive shaped objects. Several sources of stereo information are used to gather 3D information in order to obtain a model of the object. Using a RANSAC segmentation algorithm, the model parameters are estimated and a set of feasible grasps are computed. This approach is validated in both simulated and real underwater scenarios.This research was partly supported by Spanish Ministry of Research and Innovation DPI2011-27977-C03 (TRITON Project), by Foundation Caixa Castelló Bancaixa PI-1B2011-17, by Universitat Jaume I PhD grants PREDOC/2012/47 and PREDOC/ 2013/46, and by Generalitat Valenciana PhD grant ACIF/2014/298

Vareniclina. Un paso más en la lucha contra el tabaquismo

Recientemente la Food and Drugs Administration ha aprobado Vareniclina, fármaco para la deshabituación tabáquica que presenta un novedoso mecanismo de acción, agonismo parcial de receptores nicotínicos de acetilcolina a4ß2.Hemos revisado la farmacología, eficacia y seguridad de Vareniclina y su utilidad en los procesos de deshabituación, usando como fuentes bibliográficas la base de datos MEDLINE , MD consults, American journal of Addictions y distintos manuales de referencia.De los tres ensayos clínicos publicados, dos de ellos, Jorenby y Gonzales comparan la eficacia y seguridad de Vareniclina 1mg/12h frente a Bupropion 150mg/12h y placebo, durante un periodo de 52 semanas, obteniéndose los siguentes resultados: 23% de abstinencia con Vareniclina, 14,6% con Bupropion y 10,3% con Placebo en el ensayo de Jorenby. Resultados similares obtuvo Gonzales: 21,9% de abstinencia con Vareniclina frente a 16,1% con Bupropion y 8,4% con placebo.El ensayo Tonstad determina que los pacientes que dejan de fumar tras 12 semanas con Vareniclina mantienen porcentajes elevados en las 12 semanas adicionales de tratamiento y hasta 52 semanas totales, obtuviéndose un 49,6% de abstinencia con Vareniclina frente a 36,9% con placebo.Con los estudios publicados a día de hoy, podemos concluir que Vareniclina en la dosis habitual (1mg/12h) muestra mayor eficacia a corto y largo plazo tanto frente a placebo cómo frente a tratamientos habituales en la deshabituación tabáquica, con un buen perfil de seguridad y bajo porcentaje de reacciones adversas