Abstract
A new scheme based on four-wave mixing is presented using a ring erbium-doped fibre laser and tuneable fibre Bragg gratings that can effectively perform wavelength conversion in a wide wavelength range. An application of this wavelength-conversion architecture to optical communications is also presented.

Abstract
In the present article we model the treatment of mechanically ventilated patients with nosocomial pneumonia using a generalized net. The model can be used by clinicians for diagnosis and clinical and microbiological follow-up of nosocomial pneumonia, to the decision to change the ventilator regime, to begin weaning from mechanical ventilation, or to stop the weaning trials.

Abstract
This work addresses the fractional-order dynamics during the evolution of a GA, which generates a robot manipulator trajectory. In order to investigate the phenomena involved in the GA population evolution, the crossover is exposed to excitation perturbations and the corresponding fitness variations are evaluated. The input/output signals are studied revealing a fractional-order dynamic evolution, characteristic of a long-term system memory.

Abstract
Due to the increased availability of low cost network technology, the use of networks to interconnect sensors, actuators and controllers is becoming widely accepted for the implementation of feedback control systems. Such type of feedback implementation, wherein the control loops are closed through a real-time network, are called Network Controlled Systems (NCS). When implementing a NCS, the underlying communication network must provide a timely communication service, which must be the adequate to fulfil the control application requirements. Therefore, the assessment of the network responsiveness to the real-time requirements of the control application is a fundamental issue. Both PROFIBUS and CAN networks are usually considered suitable to support small-scale NCS, due to their real-time capabilities. However, their temporal responsiveness is highly dependent on both the timing characteristics of the supported message streams, such as its periodicity and the related message lengths. In this paper, we compare the timing properties of both CAN and PROFIBUS control networks. Basically, we assess their capability to support Network Controlled Systems, through the evaluation of the related worst-case message's response time. A small example of a NCS is then used to assess the capability of the CAN control network to fulfil control application requirements.

Abstract
The Kolmogorov structure function divides the smallest program producing a string in two parts: the useful information present in the string, called sophistication if based on total functions, and the remaining accidental information. We revisit the notion of sophistication due to Koppel, formalize a connection between sophistication and a variation of computational depth (intuitively the useful or nonrandom information in a string), prove the existence of strings with maximum sophistication and show that they encode solutions of the halting problem, i.e., they are the deepest of all strings.

Abstract
In this work several numerical methods, usually used to obtain the reflectivity spectrum of Bragg gratings, are studied and general conditions required for each method are analyzed and evidenced. The results are validated by comparison with a closed form analytical solution. For gratings where the solution is not evident, Rouard's method was used as the reference solution. © 2003 IEEE.