Abstract
Fibre optic Bragg gratings (FBGs) written in normal and reduced diameter high birefringence (HiBi) fibres are studied. Chemical etching is used to reduce the diameter of fibres while the optical properties of the FBG spectrum are measured. The results obtained agree qualitatively with the stress enhanced chemical etching. The birefringence of the fibre is determined as a function of the diameter. Optical characterization of the FBG under transverse strain and temperature is also performed. The results obtained show the feasibility of the simultaneous measurement of those parameters with a HiBi FBG sensor.

Abstract
An interesting feature of current Prolog systems is the ability to define external Prolog predicates that can be written in other languages. However, an important drawback of these interfaces is the fact that they lack some important features necessary to improve both the efficiency and the transparent integration of the Prolog system and the external predicates. Such an example is the cut operation. This operation is used quite often in Prolog programs, both for efficiency and semantic preservation. However, its use after a call to an externally defined predicate can have undesired effects. For example, if we have a pending connection to another application, or if we have memory blocks allocated by an external predicate, when a cut operation occurs, we may not be able to perform generic destruct actions, such as closing the pending connection or freeing the unnecessary memory. In this work, we propose an extension of the interface architecture that allows to associate generic user-defined functions with external predicates, in such a way that the Prolog engine transparently executes them when a cut operation occurs. We describe the implementation details of our proposal in the context of the Yap Prolog system.

Abstract

Abstract
The use of wind energy has developed significantly worldwide. Wind power is the strongest growing form of renewable energy, ideal for a future with pollution-free electric power. But the integration of wind farms in power networks has become an important problem for the unit commitment and control of power plants in electric power systems. The intermittent nature of wind makes it difficult to forecast wind-produced electric energy in a wind farm even in the next hours. This paper compares the results obtained with a set of selected models for hourly electric power production forecasting in a real-life wind farm. The results show a significant improvement if previous numerical weather forecasts are used as input in hourly power forecasting models.

Abstract
A new procedure based on an ethanolic solution of the appropriate cations to obtain SrBi2Ta2O9 (SBT) thin films is described, reducing the necessity of toxic organicals. According to X-ray diffraction analysis the desired SBT crystalline phase is obtained after heat treatment at 720 degrees C, in air, for 20 min. The ferroelectric properties of the obtained thin film include a remnant polarization value of 5,0 mu C/cm(2) and a coercive field of 50 kV/cm, which are rather good results for a stoichiometric SBT thin film.

Abstract
A sensing head based on two fiber Bragg gratings arranged in a twisted configuration is proposed to measure three parameters simultaneously, namely 1) temperature, 2) strain, and 3) transverse load. One of the gratings is impressed into a high-birefringence fiber that provides two distinct spectral signatures, which, together with the signature of the second grating and the geometric characteristics of the sensing head, enable the degrees of freedom required to achieve the simultaneous measurement functionality. The resolutions achieved with this configuration for the measurement of temperature, strain, and transverse load are +/- 3.1 degrees C, +/- 46 mu epsilon, and +/- 0.01 N/mm, respectively.