No abstract

The integration of Ad-Hoc networks into real environments is now becoming more and more common and supervision and control systems are no exception. The efficiency of the communication in these networks as well as various other factors, are governed by the working area, the number of nodes, mobility, transmission power, etc. In this paper, the mobility and reachability of mobile nodes appearing spontaneously in a large installation such as can be found in a water purification system are studied. These nodes form an Ad-hoc network and communicate between each other in order to finally reach a fixed node which can offer them information from the rest of the system in real time or act as a gateway to other remote networks. The study was done analytically using stochastic activity models, and using the minimum number of nodes necessary to successfully serve a water purification system with a high percentage of communication cover.

The present systems of control based on polling by radio frequency must evolve to be able to carry advanced telecommunication services, such as capture and multimedia information management as well as control information. In this paper a supervision and control system based in public networks that complements a classic polling system allowing to incorporate new information services and eliminating the typical long delays of these kinds of systems is described. Two alternatives of communication are evaluated, point to point connections and Virtual Private Networks, VPNs/IP on ISDN, for the interconnection of the stations and the control center. For this, images are transmitted as well as the control information through both types of connection, the throughput of the transmission is evaluated and its behavior is observed. Compression techniques are used and the different parameters that can influence the compressed image quality are analyzed. The viability of this type of solution in the proposed scenarios is demonstrated.

Wireless Local area networks (wLANs), particularly from standards 802.1b/g, have become extremely widespread in a very short time, in society in general as well as at an industrial level. One of the limitations of this technology is its coverage. The family of new standards, such as 802.16, allows us to overcome these limitations, enabling then their use as Metropolitan Area Networks (MAN), as required by some application domains of industrial networks. In the present work we present an application of this technology in telemonitoring systems on metropolitan areas which shows their potential, but also the complexity of predicting their behaviour in a dynamic scenario such as a large city. Copyright

The impact of the use of mobile devices by means of GPRS (General Packet Radio Service) technology to access environmental information in real time, provided by sensors strategically placed in a metropolitan area has been studied with the objective of using this information to find out rainfall volume and phreatic levels in times of emergency. This allows the technical services to make the correct decisions in the management ofa large network ofpump stations, flood gates, etc. It is demonstrated that this is a reliable system with an acceptable response time. The system being tested is integrated into a powerful supervision and control system that works in the purification network of the city of Valencia. It has been developed jointly by the "Ciclo Integral del Agua" and the Technical University of Valencia.