COSMO Second Generation (CSG) system has been conceived, according to the requirements stated by ASI and I-MoD, at the twofold need of ensuring operational continuity to the currently operating “first generation” COSMO-SkyMed (CSK) spacecraft constellation, while achieving a generational step ahead in terms of functionality and performance. The improved quality of the imaging service is among the foremost characteristics of CSG (see [5]), providing the End Users with new/enhanced capabilities in terms of higher number of images and increased image quality (i.e. larger swath, and finer resolution) with respect to COSMO-SkyMed (first generation) spacecrafts currently in operation, along with additional capabilities (e.g. full polarimetric SAR acquisition mode). The greater operative versatility in system resources management is one of the key aspects of the design approach. Some examples are the satellite agility both at platform and antenna level, used to increase the density of acquisitions in a fixed region, the capability to adapt operative profiles to system environment (e.g. sun illumination, downlink scenarios), service request planning process not only function of the priority but also able to maximize the system resources exploitation.

Vessel maintenance entails periodic visual inspections of internal and external parts of the vessel hull in order to detect the typical defective situations affecting metallic structures, such as cracks, corrosion, etc. This paper presents the first steps towards a roboticized visual inspection system aiming at automating as much as possible the whole inspection process currently undertaken by human surveyors. Occurrence of defects are first outlined, followed by a brief description of the whole system. Next, details for one of the robotic platforms to be used are given, as well as for the image processing algorithms dealing with the visual detection of defects.

Reliable multicast is a powerful communication primitive for structuring distributed programs in which multiple processes must closely cooperate together. We propose a protocol for supporting reliable multicast in a distributed system that includes mobile hosts and evaluate the performance of our proposal through simulation We consider a scenario in which mobile hosts communicate with a wired infrastructure by means of wireless technology. Our proposal provides several novel features. The sender of each multicast may select among three increasingly strong delivery ordering guarantees: FIFO, causal, total. Movements do not trigger the transmission of any message in the wired network as no notion of hand-off is used. The set of senders and receivers (group) may be dynamic. The size of data structures at mobile hosts, the size of message headers, and the number of messages in the wired network for each multicast are all independent of the number of group members. The wireless network is assumed to provide only incomplete spatial coverage and message losses could occur even within cells. Movements are not negotiated and a mobile host that leaves a cell may enter any other cell, perhaps after a potentially long disconnection. The simulation results show that the proposed protocol has good performance and good scalability properties.

We propose a multicast protocol for a distributed system that includes mobile hosts. The protocol guarantees reliable delivery, i.e. delivery of every multicast and absence of duplicates. The sender of each multicast may select among three increasingly strong delivery ordering guarantees: FIFO, causal, total. We make loose assumptions on the underlying computing system: (i) we consider an unreliable wireless network i.e. one that provides only incomplete spatial coverage and such that messages could be lost even within cells (e.g., due to physical obstructions); (ii) movements are unpredictable, i.e. a user that leaves a cell may enter any other cell, perhaps after a potentially long disconnection. Our solution does not store any sensible state information at mobile support stations, thus movements do not trigger the transmission query message in the wired network and no notion of hand-off is used. Furthermore, movements at inopportune times can cause only occasional performance penalty but do not affect correctness. Weak assumptions on the underlying computing system, absence of state information at mobile support stations and loose mobility assumptions, contribute to improve the reliability of applications deployed over the proposed protocol.