Vision-based localization of an underwater robot in a structured environment

This paper presents a vision-based localization approach for an underwater robot in a structured environment. The system is based on a coded pattern placed on the bottom of a water tank and an onboard down looking camera. Main features are, absolute and map-based localization, landmark detection and tracking, and real-time computation (12.5 Hz). The proposed system provides three-dimensional position and orientation of the vehicle along with its velocity. Accuracy of the drift-free estimates is very high, allowing them to be used as feedback measures of a velocity-based low-level controller. The paper details the localization algorithm, by showing some graphical results, and the accuracy of the system

Estándares e indicadores de calidad para bibliotecas de instituciones de educación superior

Esta publicación propone un conjunto de estándares e indicadores de calidad para el desarrollo de las bibliotecas en las instituciones de educación superior, con el objetivo de que estas desarrollen procesos de autoevaluación y medición de la calidad en el desarrollo de sus actividades.

A behavior-based scheme using reinforcement learning for autonomous underwater vehicles

This paper presents a hybrid behavior-based scheme using reinforcement learning for high-level control of autonomous underwater vehicles (AUVs). Two main features of the presented approach are hybrid behavior coordination and semi on-line neural-Q_learning (SONQL). Hybrid behavior coordination takes advantages of robustness and modularity in the competitive approach as well as efficient trajectories in the cooperative approach. SONQL, a new continuous approach of the Q_learning algorithm with a multilayer neural network is used to learn behavior state/action mapping online. Experimental results show the feasibility of the presented approach for AUVs

Política de desarrollo de colecciones Biblioteca Universidad del Rosario

Con el propósito de garantizar la prestación de servicio adecuado a las necesidades bibliográficas y documentación académica especializada la Biblioteca de la Universidad del Rosario seguirá la política de desarrollo de colecciones, diseñada por la Biblioteca y aprobada por todos los estamos de la Universidad. Esta política tiene en cuenta el PEI y el Plan de Desarrollo de la Universidad y se basará en un proceso permanente de evaluación que permita determinar las fortalezas y debilidades de la biblioteca, y así lograr el desarrollo justo y equilibrado.

La 'Academia de Leyes y Cánones' de la Universidad de Oviedo, también denominada 'De ambos derechos' durante el reinado de Carlos III.

Investigación histórica donde se analiza el papel jugado en el desarrollo de los estudios de derecho por parte de las Academias jurídicas existentes en la Universidad de Oviedo durante el reinado de Carlos III. La ejecución del Plan de Estudios de 1774 supuso la incorporación a la Universidad de las tres Academias privadas que entonces existían en Oviedo. En esta investigación, a partir de la documentación manuscrita conservada se abordan tres aspectos. En primer lugar, la denominación de la Academia, pues en el Plan de Estudios de 1774 se identifica como 'Academia de Leyes y Cánones', en las actas universitarias elevadas a la Diputación del Principado, figura como 'Academia de Ambos Derechos' y en el dilatado proceso de reglamentación de la misma en el recurso elevado al Consejo de Castilla se describe como: 'Las dos academias de Cánones y Leyes de la Universidad de Oviedo'. En segundo lugar se repasa, el régimen legal que, conforme a dicho Plan de Estudios de 1774, establece minuciosamente la organización interna de esas Academias y sus actividades, así como la creación de otras dos Academias de carácter voluntario, una de las cuáles se vincula directamente con la formación en la práctica procesal y en los conocimientos del Derecho público. Por último, se analiza el conflicto surgido a raíz de una modificación en 1782 del reglamento vigente a partir del proceso de selección de su presidente o gimnasiarca, que originó un recurso al Consejo de Castilla, implicando más tarde a la Diputación del Principado, conflicto que no produjo resultados traumáticos.

Policy gradient based Reinforcement Learning for real autonomous underwater cable tracking

This paper proposes a field application of a high-level reinforcement learning (RL) control system for solving the action selection problem of an autonomous robot in cable tracking task. The learning system is characterized by using a direct policy search method for learning the internal state/action mapping. Policy only algorithms may suffer from long convergence times when dealing with real robotics. In order to speed up the process, the learning phase has been carried out in a simulated environment and, in a second step, the policy has been transferred and tested successfully on a real robot. Future steps plan to continue the learning process on-line while on the real robot while performing the mentioned task. We demonstrate its feasibility with real experiments on the underwater robot ICTINEU AUV

Autonomous underwater vehicle control using reinforcement learning policy search methods

Autonomous underwater vehicles (AUV) represent a challenging control problem with complex, noisy, dynamics. Nowadays, not only the continuous scientific advances in underwater robotics but the increasing number of subsea missions and its complexity ask for an automatization of submarine processes. This paper proposes a high-level control system for solving the action selection problem of an autonomous robot. The system is characterized by the use of reinforcement learning direct policy search methods (RLDPS) for learning the internal state/action mapping of some behaviors. We demonstrate its feasibility with simulated experiments using the model of our underwater robot URIS in a target following task

Towards Direct Policy Search Reinforcement Learning for Robot Control

This paper proposes a high-level reinforcement learning (RL) control system for solving the action selection problem of an autonomous robot. Although the dominant approach, when using RL, has been to apply value function based algorithms, the system here detailed is characterized by the use of direct policy search methods. Rather than approximating a value function, these methodologies approximate a policy using an independent function approximator with its own parameters, trying to maximize the future expected reward. The policy based algorithm presented in this paper is used for learning the internal state/action mapping of a behavior. In this preliminary work, we demonstrate its feasibility with simulated experiments using the underwater robot GARBI in a target reaching task

Estimating the motion of an underwater robot from a monocular image sequence

When underwater vehicles perform navigation close to the ocean floor, computer vision techniques can be applied to obtain quite accurate motion estimates. The most crucial step in the vision-based estimation of the vehicle motion consists on detecting matchings between image pairs. Here we propose the extensive use of texture analysis as a tool to ameliorate the correspondence problem in underwater images. Once a robust set of correspondences has been found, the three-dimensional motion of the vehicle can be computed with respect to the bed of the sea. Finally, motion estimates allow the construction of a map that could aid to the navigation of the robot

Correction of shading effects in vision-based UUV localization

This paper describes the improvements achieved in our mosaicking system to assist unmanned underwater vehicle navigation. A major advance has been attained in the processing of images of the ocean floor when light absorption effects are evident. Due to the absorption of natural light, underwater vehicles often require artificial light sources attached to them to provide the adequate illumination for processing underwater images. Unfortunately, these flashlights tend to illuminate the scene in a nonuniform fashion. In this paper a technique to correct non-uniform lighting is proposed. The acquired frames are compensated through a point-by-point division of the image by an estimation of the illumination field. Then, the gray-levels of the obtained image remapped to enhance image contrast. Experiments with real images are presented

A review of sensor fusion techniques for underwater vehicle navigation

This work provides a general description of the multi sensor data fusion concept, along with a new classification of currently used sensor fusion techniques for unmanned underwater vehicles (UUV). Unlike previous proposals that focus the classification on the sensors involved in the fusion, we propose a synthetic approach that is focused on the techniques involved in the fusion and their applications in UUV navigation. We believe that our approach is better oriented towards the development of sensor fusion systems, since a sensor fusion architecture should be first of all focused on its goals and then on the fused sensors

La revolución democrática de Rafael Correa

El objetivo de este documento es dar luces acerca del proceso que se inició en Ecuador desde enero de 2006 y que se inscribe en el denominado socialismo del siglo XXI. En ese sentido, el texto estará dividido en cuatro partes. En la primera, se estudiará el perfil de Rafael Correa, lo que implica un estudio de su formación profesional, su carrera política y su plataforma ideológica: Alianza PAÍS. En segundo lugar se analizará la propuesta para la convocatoria de una asamblea constituyente. Al respecto se hará un paralelo entre el momento actual y el ambiente previo a la redacción de la Constitución de 1998; asimismo, se estudiarán los choques entre las diferentes ramas del poder público en torno a la convocatoria para dicha asamblea y se identificarán, de forma sintética, los puntos de la propuesta del gobierno para la elaboración de la nueva Carta Magna. En tercer lugar, se abordarán los asuntos económicos con base en tres puntos: la renegociación de la deuda externa y la propuesta del Banco del Sur, la gestión de los recursos naturales y el papel del Estado en la economía. Finalmente, se examinarán aspectos generales de la política exterior ecuatoriana, especialmente en lo referente a las relaciones con Colombia.

Mission control system for dam inspection with an AUV

This paper presents a complete control architecture that has been designed to fulfill predefined missions with an autonomous underwater vehicle (AUV). The control architecture has three levels of control: mission level, task level and vehicle level. The novelty of the work resides in the mission level, which is built with a Petri network that defines the sequence of tasks that are executed depending on the unpredictable situations that may occur. The task control system is composed of a set of active behaviours and a coordinator that selects the most appropriate vehicle action at each moment. The paper focuses on the design of the mission controller and its interaction with the task controller. Simulations, inspired on an industrial underwater inspection of a dam grate, show the effectiveness of the control architecture

Using petri nets to specify and execute missions for autonomous underwater vehicles

This paper presents the design and implementation of a mission control system (MCS) for an autonomous underwater vehicle (AUV) based on Petri nets. In the proposed approach the Petri nets are used to specify as well as to execute the desired autonomous vehicle mission. The mission is easily described using an imperative programming language called mission control language (MCL) that formally describes the mission execution thread. A mission control language compiler (MCL-C) able to automatically translate the MCL into a Petri net is described and a real-time Petri net player that allows to execute the resulting Petri net onboard an AUV are also presented

ICTINEUAUV wins the First SAUC-E competition

A pioneer team of students of the University of Girona decided to design and develop an autonomous underwater vehicle (AUV) called ICTINEU-AUV to face the Student Autonomous Underwater Challenge-Europe (SAUC-E). The prototype has evolved from the initial computer aided design (CAD) model to become an operative AUV in the short period of seven months. The open frame and modular design principles together with the compatibility with other robots previously developed at the lab have provided the main design philosophy. Hence, at the robot's core, two networked computers give access to a wide set of sensors and actuators. The Gentoo/Linux distribution was chosen as the onboard operating system. A software architecture based on a set of distributed objects with soft real time capabilities was developed and a hybrid control architecture including mission control, a behavioural layer and a robust map-based localization algorithm made ICTINEU-AUV the winning entry