Javier Pérez

Análisis comparativo de tendencias en la precipitación, por distintos inputs, entre los dominios hidrológicos del Segura y del Júcar (1958-2008)

Several studies have recently analized the trends in the precipitation depending on the type of meteorological conditions that provokes it. This new methodology has already been applied on the analisys of the precipitation in the Valencia Region. The types of precipitation are: a) convective, b) frontal systems, c) Mediterranean advections. With this study we detect significant trends that would not have been working only with total precipitations. The objective of this work is to expand this analisys to two near areas and compare results. We are working on the hidrographics basin of Segura and Jucar. The results show clear decreasing trends of the precipitation for the frontal system type and also for the advections from the North. There is similar behaviour between the two basins.

Tendencias en la precipitación, por distintos inputs, en el sector central de la Península Ibérica (1958-2008)

Previous papers from the CEAM Group in relation to the analysis of precipitation by meteorological origin, have permitted the detection of negative trends in the precipitation for frontal systems and continental advections (Northern) in the last 50 years. These negative trends have had important repercussions in the inland areas of the Valencia Region and not on the coast. The objective of this work is to analyze if the same decreasing trends can be detected in the precipitations from the Atlantic origin in areas of the interior of the Iberian Peninsula. In order to do that we have worked in two sectors, the North and the South of the Central System. We worked with the same methodology of desaggregation. The results not only confirm the hypothesis of precipitation decrease but show generalized trends in decreasing totals precipitations, especially in the North of the Central System.

FPGA-based visual control of robot manipulators using dynamic perceptibility

This paper presents an implementation of a new direct visual controller based on field programmable gate arrays. This is used to perform the guidance of robot manipulators using visual information. An embedded system architecture to control a seven degrees of freedom robot is proposed taking into account the robot dynamics. Additionally, the concept of dynamic perceptibility, which provides information about the system capability to track objects using direct visual servoing, is defined. This concept is integrated in the proposed controller and implemented in the embedded system for robot and image singularity avoidance. The obtained results show how the hardware implementation of the visual control system can improve the speed performance. Additionally, different experiments are described to show the system behavior when a trajectory close to a singularity is obtained.

FPGA-based framework for dynamic visual servoing of robot manipulators

This paper describes a whole new framework to quickly develop dynamic visual servoing systems embedded in an FPGA. Parallel design of the algorithms increases the precision of this kind of controllers, whereas minimizes the response time. Embedding dynamic visual servoing algorithms converts these systems into real-time systems. Additionally, an optimal control framework to dynamically visual control robot arms is proposed. The architecture re-configurability is tested with the implementation of two dynamic visual servoing controllers. One of the implemented controllers is derived from the proposed control framework and the other is the well-known image transpose Jacobian controller. From these experiments, FPGA resources utilization and timeline of the pipeline show the optimization of the proposed framework.