Ce mémoire s'emploie à étudier les corps quadratiques réels ainsi qu'un élément particulier de tels corps quadratiques réels : l'unité fondamentale. Pour ce faire, le mémoire commence par présenter le plus clairement possible les connaissances sur différents sujets qui sont…

One of the key aspects in the design of an architecture for autonomous agents is the way in which beleifs are revised in the face of new information. An intelligent agent must be prepared to handle new information (be it…

This work extends the semantics and implementation of fuzzy prolog presented in [VGM02] in order to include Default Knowledge capability. The new semantic allows non-uniform default assumptions and has Closed World Assumption (CWA) and Open World Assumption (OWA) as particular…

Scientific knowledge and skills acquired by students during pre-university education has diminished since legislative changes were introduced in Spain during the 1990's. As a result, education in the field of science is suffering. Some initiatives are currently underway in Great…

Web-based learning environments are becoming increasingly popular in higher education. One of the most important web-learning resources is the virtual laboratory (VL), which gives students an easy way for training and learning through the Internet. Moreover, on-line collaborative communication represents…

Data mining is at the core of the knowledge discovery process. However, an initial preprocessing step is crucial for assuring reliable results within this process. Preprocessing of data is a time-consuming and non-trivial task since data quality issues should be…

Resumo: A expressiva troca de germoplasma com outros países, por meio da importação e exportação de produtos agrícolas representa um aumento no risco de introdução desta praga no Brasil, por isso a importância do levantamento de informações acerca das características…

Knowledge on evapotranspiration is essential in quantifying water use depletion and to allocate scarce water resources to competing uses. Despite that an extensive literature describes the theoretical mechanisms of turbulent water vapour transport above and within crop canopies fewer studies…

La presente Tesis Doctoral tiene como objetivo general el empleo de sistemas sensoriales de visión y fuerza conjuntamente para realizar el guiado de robots en aquellas tareas en las que no solo se requiere controlar la trayectoria del robot sino…

One of the most difficult problems that humanity currently faces is the sustainable development of our society, i.e. how to meet the needs of the present without compromising the ability of future generations to meet their own needs. Solving this…