Abstract
Reliable multicast protocols can strongly simplify the design of distributed applications. However it is hard to sustain a high multicast throughput when groups are large and heterogeneous. In an attempt to overcome this limitation, previous work has focused on weakening reliability properties. In this paper we introduce a novel reliability model that exploits semantic knowledge to decide in which specific conditions messages can be purged without compromising application correctness. This model is based on the concept of message obsolescence: A message becomes obsolete when its content or purpose is overwritten by a subsequent message. We show that message obsolescence can be expressed in a generic way and can be used to configure the system to achieve higher multicast throughput.

Abstract
This paper proposes a method to quickly and accurately predict the dynamic response of a power system during an under-frequency load shedding scenario. Emergency actions in a power system due to loss of generation typically calls for under-frequency load shedding measures to avoid potential collapse due to the lack of time in which to correct the imbalance via other means. Due to the slow and repetitious use of dynamic simulators the need for a fast and accurate procedure is evident when calculating optimal bad-shedding strategies A neural network (NN) seems to he an ideal solution for a quick and accurate way to replace standard dynamic simulations. The steps taken to produce a viable NN and corresponding results will he discussed.

Abstract
DYNAD, a Standards, Measurements and Testing project supported by the European Commission within the Framework IV activities, is a research project aiming at the investigation of test procedures for evaluating the dynamic performances of A/D converters and S/H circuits. The paper concisely reports about the activities carried out in the first months of the project, activities which aim at improving the existing norms for what concerns the "classical" dynamic test methods for A/D converters, based on the use of sinusoidal stimuli. Web links are provided so that any interested party may contribute his/her opinion on the developed draft. Then, the research activities planned for the following years are briefly illustrated.

Abstract
Psychrometer sensors are widely used for monitoring greenhouse air humidity because of its simplicity, low cost and accuracy. For proper operation the wick, which is immersed in a water reservoir, must maintain a continuous supply of water to the wet bulb temperature sensor. This implies the need to refill periodically the water reservoirs, which is the major limitation of these sensors. To avoid this problem an electronic psychrometric sensor was developed. A microcontroller is used to read the wet and dry bulbs temperatures and compute the vapor pressure and relative humidity. In addition, it controls a micro heat pump to supply continuously water to the reservoir.

Abstract
We propose a Model Predictive Control (MPC) framework to generate feedback controls for time-varying nonlinear systems with input constraints. One of the main features of this framework is to allow the feedback laws to be discontinuous and thereby enlarge the class of nonlinear systems that can be stabilized by continuous-time MPC. We consider a continuous-time MPC framework and perform a continuous-time stability analysis while considering that the inter-sampling times are nonzero and that the open-loop optimal control problems are solved at every sampling instant. The feedback law generated by MPC is not a function of the state at every instant of time, rather it is a function of the state at the last sampling instant. The trajectories resulting from this "sampling-feedback" are well-defined even when the feedback is discontinuous. Important classes of nonlinear systems that could not be stabilized by a continuous feedback, such as the nonholonomic systems, can now be addressed in a continuous-time MPC framework.

Abstract
In Distributed Computer-Controlled Systems (DCCS), a special emphasis must be given to the communication infrastructure, which must provide timely and reliable communication services. CAN networks are usually suitable to support small-scale DCCS. However, they are known to present some reliability problems, which can lead to an unreliable behaviour of the supported applications. In this paper, an atomic multicast protocol for CAN networks is proposed. This protocol explores the CAN synchronous properties, providing a timely and reliable service to the supported applications. The implementation of such protocol in Ada, on top of the Ada version of Real-Time Linux is presented, which is used to demonstrate the advantages and disadvantages of the platform to support reliable communications in DCCS.