Time synchronization is an important part of distributed applications over a sensor network. In this work we investigate time synchronization problems over a shallow UWSN, taking into account all main communication challenges of the water channel and observing its behavior in simulation and real tests. It is proposed an hybrid frame based time synchronization using both, LFM and OFDM communication with channel impulse response equalization. Simulation results show how Hybrid synchronization outperforms existing synchronization protocols and how these results are affected in real water tests.

Last generation storage rings, both light sources and colliders, needs many different diagnostic systems to achieve specification goals. Many commercially available diagnostics are used to measure real-time accelerators performance. Nevertheless going towards higher luminosities or lower emittance, diagnostics need to be always more sophisticated. At DAFNE, the LNF e+/e- F-factory, colliding at 1.02 GeV energy in c.m., efforts are carrying on to achieve higher luminosities for the KLOE detector. Given that a ~20-25% discrepancy has been measured between the extrapolated 10 bunches peak luminosity and the standard fill pattern (~100 bunches) one, it is necessary to investigate what really happens and why. Letting apart the trivial case of measurement non-linearity or saturation in KLOE, used as precision luminosity monitor, new diagnostic techniques are needed. A new diagnostics tools, based on infrared time resolved multi-pixels detector and funded by CSNV of INFN is under test at LNF to help this analysis.

For Run-2 of the LHC a fourth, innermost Pixel Detector layer on a smaller radius beam pipe has been installed in the ATLAS Detector to add redundancy against radiation damage of the current Pixel Detector and to ensure a high quality tracking and b-tagging performance of the Inner Detector over the coming years until the High Luminosity Upgrade. To improve the overall physics performance of the ATLAS detector, a local support structure in carbon fiber has been developed with an overall planarity of 350μm, targeting for a low material budget subdetector with a total radiation length of only 1.5 Xo. An overview of the new sub-detector called the Insertable B-layer (IBL) will be given, followed by the stave loading process with focus on the stave planarity metrology measurements and module positioning precision. Metrologies surveys on the IBL Support Tube and final package after stave integration will been shown.

Analysis and design of flexible retaining walls under seismic actions is required in many applications, but is not fully established yet due to the involved complex soil-wall interaction mechanisms. Technology for advanced field measurements and integration with refined numerical analyses represent an attractive option to shade light on this relevant topic of seismic geotechnics. In the present paper, experimental measurements both dynamic and static recorded on a full-scale retaining wall are briefly discussed. Their relevance in view of the development of an effective soil-structure numerical model is pointed out. A multi-level approach to the optimisation of the FE model is discussed, pointing out the potentialities of the integration between field investigations and numerical modelling. The latter is aimed at providing reliable results concerning both the interpretation of the static response and the dynamic behaviour under seismic loads for the development of rational and effective performance based design and assessment procedures.

The definition of a suitable geotechnical model is a primary task in performing site response analyses. Soil mechanical properties should be carefully estimated and soil profile inhomogeneities should be taken into account to obtain appropriate results. In this paper the dynamic response of a bilayer soil profile is investigated by means of 1-g shaking table tests. A back-analysis procedure to estimate the mechanical parameters and the inhomogeneity rating of the soil profile, by means of accelerometric measures, is presented. The dynamic response of the geotechnical model obtained is simulated through a 1-D approach and compared with experimental results.