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[Resumen] La investigación robótica requiere plataformas experimentales que tengan una arquitectura abierta. Existen varios equipos comerciales con estas características, pero tienen un gran coste económico, siendo esto un inconveniente en el desarrollo de algoritmos. En este artículo presentamos los avances implementados en nuestro vehículo terrestre no tripulado BLUE enfocados a la investigación y desarrollo de métodos para manipulación móvil en entornos exteriores no estructurados. Además, detallamos el hardware y software añadidos a BLUE en los últimos años y mostramos los paquetes y experimentos que se han realizado tanto para las tareas de localización y navegación, como para las operaciones de manipulación de objetos en robótica móvil. [Abstract] Robotic research requires experimental platforms with an open architecture. Several commercial equipment with these characteristics exist, but they have a high economic cost, being a disadvantage in the development of algorithms. In this paper we present the advances implemented in our BLUE unmanned ground vehicle focused on the development of Mobile Manipulation for Unstructured Outdoor Environments (MOMUE). In addition, we detail the hardware and software incorporated throughout the project and show the packages and experiments we have performed for object localization, navigation and manipulation in mobile robotics Esta investigación ha sido financiada por el gobierno regional de la Generalitat Valenciana, FEDER y el Ministerio Español de Innovación y Universidades a través de los proyectos PROMETEO/2021/075, IDIFEFER/2020/003, RTI2018-094279-B-I00 y la beca ACIF/2019/088 Generalitat Valenciana. Conselleria d’Innovació, Universitats, Ciència i Societat Digital; PROMETEO/2021/075 Generalitat Valenciana; IDIFEFER/2020/003

Soaring landbirds typically exploit atmospheric uplift as they fy overland, displaying a highly efective energy-saving locomotion. However, large water bodies lack thermal updrafts, potentially becoming ecological barriers that hamper migration. Here we assessed the efects of a sea surface on the migratory performance of GPS-tagged white storks (Ciconia ciconia) before, during and after they crossed the straits of Gibraltar. Oversea movements involved only fapping and gliding and were faster, traversed in straighter, descending trajectories and resulted in higher movementrelated energy expenditure levels than overland, supporting the water barrier hypothesis. Overland movements at both sides of the sea straits resulted in tortuous routes and ascending trajectories with pre-crossing fights showing higher elevations and more tortuous routes than post-crossing, thus supporting the barrier negotiation hypothesis. Individual positions at both ends of the sea narrow were predicted by zonal winds and storks´ location at entry in the European hinterland, and birds did not show compensational movements overland in anticipation to subsequent wind displacements oversea. The length of the water narrow at departure shore, the elevation therein and the winds on route afected major components of sea crossing performance (such as distances and times overwater, minimum elevations, climb angles, speeds and energy expenditure), supporting the departure position and oversea winds hypotheses. In summary, our study provides a prime example at high temporal resolution of how birds adjust their behavior and physiology as they interact with the changing conditions of the travelling medium, reallocating resources and modifying their movement to overcome an ecological barrier.

In birds, the magnitude of the adrenocortical stress response can be down‐regulated during specific life‐history stages. Such modulation likely occurs when the effects of mounting robust corticosterone (Cort) elevations interfere with the normal progression of critical lifecycle activities (e.g. development, molt, migration, reproduction). The Developmental Hypothesis posits that altricial birds should display a “Stress Hyporesponsive Period” during the early post‐natal life stages, characterized by reduced adrenocortical stress responses compared to adult birds and a gradual age‐related increase. Such modulation would allow avoiding the potential deleterious effects that long‐term elevations of circulating Cort might exert on growth and development, when the physiological and behavioral abilities to cope with disturbance are limited. Two proximate hypotheses have been proposed to explain this age‐dependent pattern of Cort secretion. The Maturation Hypothesis proposes a progressive age‐related growth, maturation and enhanced sensitivity to sensory input of the Hypothalamic‐Pituitary‐Adrenal (HPA) axis tissues, whereas the Negative Feedback Attenuation Hypothesis proposes a gradual attenuation in the intensity of the negative feedback in the HPA axis. Here we tested these hypotheses by experimentally inducing negative feedback on the HPA axis via dexamethasone (DEX) treatment in nestling white storks Ciconia ciconia. Nestling age positively affected stress‐induced plasma Cort (STRESS‐Cort) levels during experimental handling and restraint, thus supporting the Developmental Hypothesis. DEX treatment significantly reduced STRESS‐Cort levels compared to saline (SAL) treatment, thus eliciting the expected negative feedback on the HPA axis. However, inter‐ and intra‐individual comparisons indicated no age effects on the intensity of the negative feedback exerted by DEX. Our results do not support the Negative Feedback Attenuation Hypothesis and suggest that progressive Maturation of the HPA axis tissues is the proximate mechanism responsible for age‐related changes in the stress response during avian post‐natal development. We encourage further tests of the proposed proximate mechanisms during migration, breeding and molt., This work was supported by the Spanish Ministry of Economy and Competitiveness and European funds (project CGL2012-32544 to J.B.) and the Spanish Ministry of Agriculture, Food and the Environment (Organismo Autónomo de Parques Nacionales, grant 511/2012 to J.B.), the University of Saskatchewan (Isabel Maria Lopez Martinez Memorial Scholarship to F.T-M), and the Spanish Council of Science CSIC (CSIC Projects 201730I011 and i-link 0564 to J.B.).

In birds, the use of corticosterone (Cort) implants is a frequent tool aimed at simulating systemic elevations of this hormone and studying effects on biological traits (e.g. physiology, morphology, behavior). This manipulation may alter adrenocortical function, potentially changing both baseline (Cort) and stress-induced (Cort) plasma Cort levels. However, implant effects on the latter trait are rarely measured, disregarding downstream consequences of potentially altered stress responses. Here, we analyzed the effects of Cort implants on both Cort and Cort in nestling and adult European white storks, Ciconia ciconia. In addition, we performed a review of 50 studies using Cort implants in birds during the last two decades to contextualize stork results, assess researchers' patterns of use and infer current study biases. High and low doses of Cort implants resulted in a decrease of both Cort (31-71% below controls) and Cort (63-79% below controls) in storks. Our literature review revealed that Cort generally increases (72% of experiments) whereas Cort decreases (78% of experiments) following implant treatment in birds. Our results challenge and expand the prevailing assumption that Cort implants increase circulating Cort levels because: (i) Cort levels show a quadratic association with implant dose across bird species, and decreased levels may occur at both high and low implant doses, and (ii) Cort implants also decrease Cort levels, thus producing stresshyporesponsive phenotypes. It is time to work towards a better understanding of the effects of Cort implants on adrenocortical function, before addressing downstream links to variation in other biological traits.

In birds, the use of corticosterone (Cort) implants is a frequent tool aimed at simulating systemic elevations of this hormone and studying effects on biological traits (e.g. physiology, morphology, behavior). This manipulation may alter adrenocortical function, potentially changing both baseline (BAS-Cort) and stress-induced (STRESS-Cort) plasma Cort levels. However, implant effects on the latter trait are rarely measured, disregarding downstream consequences of potentially altered stress responses. Here we analyzed the effects of Cort implants on both BAS-Cort and STRESS-Cort in nestling and adult European white storks Ciconia ciconia. In addition, we performed a review of 50 studies using Cort implants in birds during the last two decades to contextualize stork results, assess researchers' patterns of use and infer current study biases. High and low doses of Cort implants resulted in a decrease of both BAS-Cort (31-71% below controls) and STRESS-Cort (63-79% below controls) in storks. Our review revealed that BAS-Cort generally increases (72% of experiments) while STRESS-Cort decreases (78% of experiments) following implant treatment in birds. Our results challenge and expand the prevailing assumption that CORT implants increase circulating BAS-Cort levels because: (i) BAS-Cort levels show a quadratic association with implant dose across bird species, and decreased levels may occur at both high and low implant doses, and (ii) Cort implants also decrease STRESS-Cort levels, thus producing stress hyporesponsive phenotypes. It is time to work towards a better understanding of the effects of Cort implants on adrenocortical function, before addressing downstream links to variation in other biological traits.

Comunicacion presentada en IFAC International Workshops Intelligent Assembly and Disassembly (IAD'07), Intelligent Manufacturing Systems (IMS'07), 23-25 May 2007, Campus of San Vicente del Raspeig, Alicante, Spain

In this paper, a visual servoing for the tracking of objects in a plane using a fixed camera system is shown. The method proposed of tracking makes use of a variable number of trackers determined automatically. The integration of the predictions of each of them affords a flexible and robust system of tracking. The studies of efficiency carried out reflect that the delays produced are suitable for use in visual servoing. The proposed system can be generalized to tracking three-dimensional objects with movable cameras.

Este artículo analiza diferentes experiencias docentes que tienen como finalidad el aprendizaje de la robótica en el mundo universitario. Estas experiencias se plasman en el desarrollo de varios cursos y asignaturas sobre robótica que se imparten en la Universidad de Alicante. Para el desarrollo de estos cursos, los autores han empleado varias plataformas educativas, algunas de implementación propia, otras de libre distribución y código abierto. El objetivo de estos cursos es enseñar el diseño e implementación de soluciones robóticas a diversos problemas que van desde el control, programación y manipulación de brazos robots de ámbito industrial hasta la construcción y/o programación de mini-robots con carácter educativo. Por un lado, se emplean herramientas didácticas de última generación como simuladores y laboratorios virtuales que flexibilizan el uso de brazos robots y por otro lado, se hace uso de competiciones y concursos para motivar al alumno haciendo que ponga en práctica las destrezas aprendidas, mediante la construcción y programación de mini-robots de bajo coste., This paper discusses different teaching experiences which aims are the learning robotics in the university. These experiences are reflected in the development of several robotics courses and subjects at the University of Alicante. The authors have created various educational platforms or they have used tools of free distribution and open source for the implementation of these courses. The main objetive of these courses is to teach the design and implementation of robotic solutions to solve various problems not only such as the control, programming and handling of robot but also the assembly, building and programming of educational mini-robots. On the one hand, new teaching tools are used such as simulators and virtual labs which make flexible the learning of robot arms. On the other hand, competitions are used to motivate students because this way, the students put into action the skills learned through building and programming low-cost mini-robots.

This paper presents a non-destructive disassembly method. It tries to make up for limitations of other methods based on contact surfaces. It uses a contact surfaces graph and shows an algorithm to obtain the movement sequence needed for the disassembly of two objects, using a composition of transfer movement. It performs a second filter to obtain the exact disassembly direction from the group of directions obtained from the contact surfaces. The filter employs a mobile robotic heuristic to feedback the contact surface graph throughout the disassembly process. The heuristic generates an environment map to infer the region where the probability of collision with the other objects is lower. To achieve the disassembly the paper presents a method for modeling the elements implied in the disassembly process. This virtual model of the environment allows us to quickly process the elements and the simulation of the movements for disassembly. This model can be used to either schedule the disassembly process or to test, during the design stage, whether the products can be easily disassembled.

An algorithm for allocating and scheduling tasks in multiprocessor environments is presented. Its main characteristic is its orientation towards machine vision applications. In this sense it deals with the peculiarities of systems which combine generic-type processors with Image Acquisition and Processing Boards. The main goal of the algorithm is total processing time reduction; such are the requirements when we deal with automated industrial inspection applications. By simultaneously tackling the phases of allocation and scheduling, the results obtained are better than those offered by traditional algorithms. The system is applied to a process of citrus fruit inspection, and its performances are also evaluated over randomly generated task graphs.

In this paper, we present the results of the extension of the mathematical morphology to color images by treating multi-channel data as vectors. The approach presented here uses the HSI and related color spaces (intuitives). A modification of the lexicographical order for vectorial processing is developed. The importance of this new method lies on automatic selection of elements of the HSI and related color spaces to form an ordering structure. The achievement of the algorithm is realized through the introduction of a weight factor to reduce the high preference of the first component of the classic lexicographical order. Experimental results demonstrate the improvement of this new method.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper describes a vergence control algorithm for a 3D stereo recovery system. This work has been developed within framework of the project ROBTET. This project has the purpose of designing a Teleoperated Robotic System for live power lines maintenance. The tasks involved suppose the automatic calculation of path for standard tasks, collision detection to avoid electrical shocks, force feedback and accurate visual data, and the generation of collision free real paths. To accomplish these tasks the system needs an exact model of the environment that is acquired through an active stereoscopic head. A cooperative algorithm using vergence and stereo correlation is shown. The proposed system is carried out through an algorithm based on the phase correlation, trying to keep the vergence on the interest object. The sharp vergence changes produced by the variation of the interest objects are controlled through an estimation of the depth distance generated by a stereo correspondence system. In some elements of the scene, those aligned with the epipolar plane, large errors in the depth estimation as well as in the phase correlation, are produced. To minimize these errors a laser lighting system is used to help fixation, assuring an adequate vergence and depth extraction.

A fully integrated development tool for computer vision systems has been built in the framework of this paper. There are many applications that help the user in the design of such systems, using graphical interfaces and function libraries. Even in some cases, the final source code can be generated by these applications. This paper goes a step beyond; it allows the development of computer vision systems from a distributed environment. Besides, and as a distinctive characteristic with regard to other similar utilities, the system is able to automatically optimize task scheduling and assignment, depending on the available hardware.

In the last years aperture synthesis interferometric radiometers have received a special attention by space agencies as a feasible solution to passive monitoring of the Earth at low frequencies (L-band), where classical total power radiometers would require heavy steerable antennas to meet the spatial resolution requirements (10 - 20 Km), from a low polar orbit. While the performance of such instruments is well known in the radioastronomy field, its application to Earth remote sensing is quite new. The study of different array structures, system errors, calibration and inversion methods and instrument global performance requires the implementation of a simulator of a two-dimensional space borne interferometric radiometer. It allows us to analyze not only its snap shot radiometric accuracy, but also its improvement by means of pixel averaging, that is, the averaging of the common pixels recovered in a sequence of consecutive brightness temperature images. The simulations performed use the system parameters of the planned MIRAS (microwave imaging radiometer by aperture synthesis) instrument, a Y-shaped array with 43 antennas per arm spaced 0.89 lambda, currently under study by the European Space Agency.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper presents a method for minimizing the total elapsed time spent by n tasks running on m differents processors working in parallel. The developed algorithm not only minimizes the total elapsed time but also reduces the idle time and waiting time of in-process tasks. This condition is very important in some applications of computer vision in which the time to finish the total process is particularly critical -- quality control in industrial inspection, real- time computer vision, guided robots. The scheduling algorithm is based on the use of two matrices, obtained from the precedence relationships between tasks, and the data obtained from the two matrices. The developed scheduling algorithm has been tested in one application of quality control using computer vision. The results obtained have been satisfactory in the application of different image processing algorithms.