Abstract
Interferometric systems consisting of two tandem interferometers with white-light illumination have been used as optical-fibre remote-sensing systems. Recently, it has been shown that both phase and amplitude of the output signal are significantly affected by externally induced birefringence in the fibre linking the interferometers; in some cases, this may cause total fading of the interference signal. In this letter, a new scheme is proposed to overcome this problem in white-light fibre-optic interferometric sensors. The approach is based on birefringence compensation using Faraday rotator mirror elements. The principle is experimentally verified, and the results confirm the theoretical expectation.

Abstract
Complex applications in distributed-memory parallel systems often follow a demand-driven approach with domain decomposition. A uniform data distribution among the local memories at the processing elements may require frequent remote data access. To keep the processors busy while data is remotely fetched, concurrent application processes are assigned to each transputer-based processing element. Adding more concurrent application processes in a large-scale parallel system may degrade performance, due to the traffic increase with data requests and data block replies. A conditional broadcast mechanism is implemented during data requests, to limit this flow of messages. Monitoring strategies are proposed to further reduce the messages density, and a parameterized model to measure and evaluate global execution times is presented. Simulation data running the model with up to 35 transputers show that monitoring can reduce the performance degradation when more local concurrence is added. However, if too much data replication is present, the simulation data also show that the supply of communication services at each node still imposes a burden, requiring complementary monitoring strategies to allow removal of redundant reply messages.

Abstract

Abstract
In this article, we describe the effort being carried out in the analysis, design and implementation of the control architecture for a mobile platform for autonomous transportation, surveillance and inspection in structured and semi-structured industrial environments. The control architecture is based in a hierarchical structure organized linguistically permitting the real-time parallel execution of tasks. This, architecture is composed of three levels, Organization, Coordination and Functional, structured according to the Increasing Precision with Decreasing Intelligence Principle.

Abstract

Abstract