Abstract
In this paper, we propose a real-time publish-subscribe communication scheme for IEEE 802.11e networks, named Group Sequential Communication (GSC). The GSC intends to improve the HCCA mechanism by adopting a simple approach based on the Virtual Token Passing (VTP) protocol which uses a real-time group concept, where the real-time members of the group are granted a high-priority and sequential access to the communication medium. Their main achievements are the reduction of the Polling, individual ACKs and NULL frames overheads between the controller and the polled stations. In order to improve the reliability of the GSC scheme was developed a fault-tolerant mechanism based on a block acknowledge strategy to avoid missing real-time message deadlines.

Abstract
This article describe the design, fabrication steps and experimental results of a dilatometer that will be used to characterize ceramic samples in terms of thermal expansion. The basic idea is to heat a 25 mm ceramic sample up to 1000 degrees C and register its dimension variations during the rising and the falling of the temperature. The device prototype consists in a master-slave structure since there are two control units: the high-level one (master) and a low-level one (slave). The high-level control unit will be responsible for supporting the user interface, exchanging and processing the necessary information between the user and the low-level control unit. The low-level control unit main component is a microcontroller. It is responsible for acquiring data from the strain and temperature sensors and controlling the temperature of the samples. The experimental results show that the prototype is appropriate for dilatometry essays once the maximum error was 0.037% of full-scale.

Abstract
Fractional Calculus (FC) goes back to the beginning of the theory of differential calculus. Nevertheless, the application of FC just emerged in the last two decades due to the progress in the area of nonlinear dynamics. This article discusses several applications of fractional calculus in science and engineering, namely: the control of heat systems, the tuning of PID controllers based on fractional calculus concepts and the dynamics in hexapod locomotion. © 2009 Springer-Verlag Berlin Heidelberg.

Abstract
In this paper, it is presented a brief review of the sensing applications using suspended core fibres. Since the first publication, several authors have studied their properties and possible applications in engineering. Due to their geometry, the great potential in optical sensing is in bio and gas sensing. Recently, with the possibility of inscribing Bragg grating structures on these fibres, it is possible to use them for other applications. Finally, this paper reviews the recent works with suspended core fibres for interferometry.

Abstract
An important aspect when dealing with computer control systems is the impact of control delay upon the performance of the controlled item. Such control delay may be a consequence of the computer controlled implementation or, for the case of a network based control system, can be the consequence of the use of a communication network to interconnect sensors and actuators with the controller. Basically, control applications require a predictable delay between measurement and actuation, with small variability, i.e., small jitter. In this paper we present some simulation results concerning the impact of a varying control delay upon the performance of a DC-Motor, both for a centralized computer-controlled setup and for a network based control system. The results for the centralized setup were also experimentally confirmed. For the network-based setup it was used the h-BEB real-time communication protocol. The evaluated scenarios were simulated using the True Time simulator that is based in MATLAB/Simulink. The experimental tests were developed in LabVIEW, where the controller task was executed as a software routine. The tests consisted in the variation of the sampling period and control delay to determinate the steady region of the system.

Abstract