Abstract
Dither demodulation of fibre Bragg grating sensors illuminated with multimode light from cheap compact disc laser diodes is investigated. Quasi-static temperature and strain sensitivities of 0.09 degrees C/root Hz and 0.6 mu epsilon/root Hz are obtained. It is shown that small ac signals outside the loop bandwidth can be measured using synchronous detection at double the dither frequency.

Abstract
YapOr is an or-parallel system that extends the Yap Prolog system to exploit implicit or-parallelism in Prolog programs. It is based on the environment copying model, as first implemented in Muse. The development of YapOr required solutions for some important issues, such as designing the data structures to support parallel processing, implementing incremental copying technique, developing a memory organization able to answer with efficiency to parallel processing and to incremental copying in particular, implementing the scheduler strategies, designing an interface between the scheduler and the engine, implementing the sharing work process, and implementing support to the cut builtin. An initial evaluation of YapOr performance showed that it achieves very good performance on a large set of benchmark programs. Indeed, YapOr compares favorably with a mature parallel Prolog system such as Muse, both in terms of base speed and in terms of speedups. © Springer-Verlag Berlin Heidelberg 1999.

Abstract
Greenhouse control computers are an essential part of modern greenhouse operation. Climate, irrigation and nutrient supply must be controlled, in an economically way, to produce the best crop conditions. Current research on CO2 enrichment and optimal growth strategies implies the use of powerful tools, either based on hardware or software. This paper describes the implementation of a distributed data acquisition and control system for computerised agricultural management systems. To accomplish with the emergent and future tendencies in this area the network uses different communications platforms to achieve low-cost, flexibility, and functionality. The techniques and tools, that provide to the user a transparent, friendly and intuitive Graphical User Interface will be also presented. Copyright (C) 1998 IFAC.

Abstract
An investigation is performed on the characteristics of two self-referencing resonant fiber optic intensity sensors supported by a Michelson topology. The sensors are based in transmissive and reflective configurations respectively. Via the definition of the measurement parameter (R parameter) the sensitivity and Linearity of the sensors are analyzed. The problem of sensor design and optimization is considered and the features of the two configurations are addressed.

Abstract
A closed loop technique for measuring Bragg wavelength shifts based on active wavelength tuning of a WDM coupler is presented. By stretching the coupling region of a fused biconical WDM, the 3 dB point is set by the feedback loop to always match the reflected Bragg wavelength. With this scheme, sensitivities usually associated with highly selective WDM can be obtained without compromising the measurement range.

Abstract
This paper describes the initial study of the research program being carried out on the feeding system of an industrial overlock sewing machine. The results obtained from the displacement and compression force, together with the graphic kinematic analysis, which includes the velocity and acceleration taken from the displacement-time curves of the presser foot bar, led to further understanding of the feeding system dynamics. This study is expected to provide the basis for the development of a redesigned and optimised fabric feeding system, in which the role of an actuator integrated in the presser foot bar will also be discussed as a major contribution to achieving a desired dynamic behaviour at high sewing speeds.