University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

Measuring efficiency in education: an analysis of different approaches for incorporating non-discretionary inputs

Abstract: Measuring efficiency in the education sector is a highly complex task. One of the reasons is that the main resource of schools (the type of students they have) lie outside of their control, which means that it must be treated differently to other factors in analysis. This study examines the different options available in the literature for incorporating non-controllable inputs in a data envelopment analysis in order to determine the most appropriate model for evaluating schools. Our empirical study presents the results obtained using the model proposed by Fried et al . (1999), though we use bootstrap techniques to avoid problems of bias in the estimations.

Molecular self-assembly and patterning induced by sound waves. The case of gelation.

Abstract: Recent findings evidence that cavitational and mechanical effects of ultrasound waves trigger molecular assembly and pattern formation, exemplified by organogels and ordered structures. Although sonication-assisted aggregation has become a well-established protocol, the science behind it is often overlooked. In this tutorial review various aspects of ultrasound-driven reactions are introduced, highlighting organic and metal coordination compounds, as well as recent applications focused on polymer structures. Given the importance of supramolecular assemblies, especially hydrogels, as biomaterials and vehicles for drug transport and delivery, sound waves thus provide a facile entry to new forms of soft matter and functionalized materials.

On Fractional PIλ Controllers: Some Tuning Rules for Robustness to Plant Uncertainties

Abstract: The objective of this work is to find out optimum settings for a fractional PIλ controller in order to fulfill three different robustness specifications of design for the compensated system, taking advantage of the fractional order, λ. Since this fractional controller has one parameter more than the conventional PI controller, one more specification can be fulfilled, improving the performance of the system and making it more robust to plant uncertainties, such as gain and time constant changes. For the tuning of the controller an iterative optimization method has been used, based on a nonlinear function minimization. Two real examples of application are presented and simulation results are shown to illustrate the effectiveness of this kind of unconventional controllers.