Reference Chaser Bandwidth Controller for Wireless QoS Mapping under Delay Constraints

Telecommunications networks are composed of functional layers acting in cascade. Quality of Service (QoS) derives from the action of each layer that must assure a specific level of quality to the upper layer in terms of performance parameters (e.g., loss, delay, jitter of the packets). Appropriate algorithms are needed to compute the bandwidth necessary so to assure the requested QoS when information is transferred from one layer to the next one below. This paper proposes a scheme that adapts the bandwidth to be allocated to a buffer which conveys heterogeneous traffic (both concerning traffic sources and QoS requirements) in a layer-in-cascade model. The proposal is focused on delay constraints. The proposed algorithm is based only on measures and does not use closed-form expressions, a priori information about traffic statistical properties, and assumptions about buffer dimension. Simulation results show the reliability of the approach in comparison with other techniques at the state of the art, thus corroborating the application of the algorithm for a large set of operative situations, including fading conditions

Counterfactual Building and Evaluation via eXplainable Support Vector Data Description

Increasingly in recent times, the mere prediction of a machine learning algorithm is considered insufficient to gain complete control over the event being predicted. A machine learning algorithm should be considered reliable in the way it allows to extract more knowledge and information than just having a prediction at hand. In this perspective, the counterfactual theory plays a central role. By definition, a counterfactual is the smallest variation of the input such that it changes the predicted behaviour. The paper addresses counterfactuals through Support Vector Data Description (SVDD), empowered by explainability and metric for assessing the counterfactual quality. After showing the specific case in which an analytical solution may be found (under Euclidean distance and linear kernel), an optimisation problem is posed for any type of distances and kernels. The vehicle platooning application is the use case considered to demonstrate how the outlined methodology may offer support to safety-critical applications as well as how explanation may shed new light into the control of the system at hand

Tracing groundwater salinization processes in coastal aquifers: a hydrogeochemical and isotopic approach in Na-Cl brackish waters of north-western Sardinia, Italy

Abstract. Throughout the Mediterranean, salinization threatens water quality, especially in coastal areas. This salinization is the result of concomitant processes related to both seawater intrusion and water–rock interaction, which in some cases are virtually indistinguishable. In the Nurra region of northwestern Sardinia, recent salinization related to marine water intrusion has been caused by aquifer exploitation. However, the geology of this region records a long history from the Palaeozoic to the Quaternary, and is structurally complex and comprises a wide variety of lithologies, including Triassic evaporites. Determining the origin of the saline component of the Jurassic and Triassic aquifers in the Nurra region may provide a useful and more general model for salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activity and recent climatic change, the Nurra has become vulnerable to desertification and, in common with other Mediterranean islands, surface water resources periodically suffer from severe shortages. With this in mind, we report new data regarding brackish and surface waters (outcrop and lake samples) of the Na-Cl type from the Nurra region, including major ions and selected trace elements (B, Br, I, and Sr), in addition to isotopic data including δ18O, δD in water, and δ34S and δ18O in dissolved SO4. To identify the origin of the salinity more precisely, we also analysed the mineralogical and isotopic composition of Triassic evaporites. The brackish waters have Cl contents of up to 2025 mg L−1 , and the ratios between dissolved ions and Cl, with the exception of the Br / Cl ratio, are not those expected on the basis of simple mixing between rainwater and seawater. The δ18O and δD data indicate that most of the waters fall between the regional meteoric water line and the global meteoric water line, supporting the conclusion that they are meteoric in origin. A significant consequence of the meteoric origin of the Na-Cl-type water studied here is that the Br / Cl ratio, extensively used to assess the origin of salinity in fresh water, should be used with care in carbonate aquifers that are near the coast. Overall, δ34S and δ18O levels in dissolved SO4 suggest that water–rock interaction is responsible for the Na-Cl brackish composition of the water hosted by the Jurassic and Triassic aquifers of the Nurra, and this is consistent with the geology and lithological features of the study area. Evaporite dissolution may also explain the high Cl content, as halite was detected within the gypsum deposits. Finally, these Na-Cl brackish waters are undersaturated with respect to the more soluble salts, implying that in a climate evolving toward semi-arid conditions, the salinization process could intensify dramatically in the near future

Status of the Cylindical-GEM project for the KLOE-2 Inner Tracker

The status of the R&D on the Cylindrical-GEM (CGEM) detector foreseen as Inner Tracker for KLOE-2, the upgrade of the KLOE experiment at the DAFNE phi-factory, will be presented. The R&D includes several activities: i) the construction and complete characterization of the full-size CGEM prototype, equipped with 650 microns pitch 1-D longitudinal strips; ii) the study of the 2-D readout with XV patterned strips and operation in magnetic field (up to 1.5T), performed with small planar prototypes in a dedicated test at the H4-SPS beam facility; iii) the characterization of the single-mask GEM technology for the realization of large-area GEM foils.Comment: 4 pages, 10 figures, Presented at Vienna Conference on Instrumentation (Feb 15-20, 2010, Vienna, Austria). Submitted to the Proceeding

DNA methylase modifications and other linezolid resistance mutations in coagulase-negative staphylococci in Italy

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Composition and structural modifications to the AI/AISI 316L sintered steel interface induced by heat treatments

After heat treatment, the aluminium coating, deposited on sintered AISI 316L austenitic stainless steel forms an interdiffusion layer. Aluminium diffuses beyond the layer/steel interface, mostly along the interconnected porosities, penetrating into the sintered steel for about 80 gm, and causing a nitrogen exchange reaction with the Cr2N phase. This leads to the formation of AlN particles. At the beginning these are tiny, then they subsequently coalesce and migrate outwards through the interdiffusion layer. The vapour phase aluminium diffusion is in accordance with thermodynamical data.At the layer/coated sintered steel interface, on the steel side, the cavity surfaces are covered by aluminium and chromium mixed films. In uncoated heat treated sintered steels, the chromium oxide films are present in all the volume. The anodic behaviour of aluminium coated and heat treated (700 -900°C) sintered steels is much better than that of the uncoated steels heat treated at the same temperatures.The improvement can be attributed to the Cr2N and Al reaction which makes passivation easier. With 1000°C heat treatment, a worsening is observed compared to the lower temperatures