Lightweight link quality estimation is crucial in wireless sensor networks. Indeed, devices with limited capabilities shall trade off between consuming their resources to maintain a precise view of ...the neighbours' link quality and to build routes almost blindly. For instance, the Routing Protocol for Low-Power and Lossy Networks (RPL), which has been recently standardised by the IETF to enable IPv6-based sensor networks, only estimates the quality of the links used to deliver data packets. However, this solution has been demonstrated to cause periods of routing instability and reduced packet delivery rates since it estimates only the quality of utilised links. To address this issue in this work we propose a lightweight link estimation procedure that exploits Trickle-based topology maintenance techniques to simultaneously estimate link qualities and propagate routing information. Our proposed scheme has been integrated in the Contiki's RPL prototype implementation. Simulation results demonstrate that our proposal is capable of measuring the quality of the links to neighbours with small overhead, which results into better routing decisions and improved packet delivery rates.
Star-forming, H\(\alpha\)-emitting clumps are found embedded in the gaseous tails of galaxies undergoing intense ram-pressure stripping in galaxy clusters, so-called jellyfish galaxies. These clumps ...offer a unique opportunity to study star formation under extreme conditions, in the absence of an underlying disk and embedded within the hot intracluster medium. Yet, a comprehensive, high spatial resolution study of these systems is missing. We obtained UVIS/HST data to observe the first statistical sample of clumps in the tails and disks of six jellyfish galaxies from the GASP survey; we used a combination of broad-band filters and a narrow-band H{\alpha} filter. HST observations are needed to study the sizes, stellar masses and ages of the clumps and their clustering hierarchy. These observations will be used to study the clump scaling relations, the universality of the star formation process and verify whether a disk is irrelevant, as hinted by jellyfish galaxy results. This paper presents the observations, data reduction strategy, and some general results based on the preliminary data analysis: the UVIS high spatial resolution gives an unprecedented sharp view of the complex structure of the inner regions of the galaxies and of the substructures in the galaxy disks; we found clear signatures of stripping in regions very close in projection to the galactic disk; the star-forming regions in the stripped tails are extremely bright and compact while we did not detect a significant number of star-forming clumps outside those detected by MUSE. The paper finally presents the development plan for the project.
To assess the status of lynx we analysed lynx signs of presence within the Ital- ian Alps from 2000–2004. A total of 411 signs of lynx presence have been collected, compared to 261 signs during the ...previous pentad. Lynx tracks were the most frequent sign of presence, followed by prey remains and direct observations. Livestock depredation has so far not been a problem in Italy. Most of the presence signs (84%) are still concentrated in the Eastern Italian Alps in Friuli V.G. and the province of Belluno. A few confirmed lynx signs of presence indicate a recolonisation of the Trentino Alto Adige region. In the western Alps (Piemonte region), most signs of lynx presence are concentrated close to the French border. The number of lynx occurring in Italy is roughly estimated to less than 20 individuals. The population cannot be considered viable and is still depending on immigration from neighboring countries.
Finite capacity planning is a central problem in manufacturing industries. At the heart of it lies a scheduling optimization problem, which has been so far studied in the optimization literature ...mainly in abstract forms, like job shop scheduling. There is a huge gap between the job shop instances used as benchmark in the literature and the scheduling instances met in real-world planning, this both with respect to instance size and to instance complexity, meaning the type of constraints and of variables considered. We present here the algorithmic core of a package primarily targeted to metallic carpentry industries, where instance types and CPU time constraints pose severe burdens on the optimization methods which can be used. We report about the results obtained by means of partial enumeration, a mathematic programming technique, here included in an Ant Colony Optimization framework.
