The Exploitation of Data from Remote and Human Sensors for Environment Monitoring in the SMAT Project

In this paper, we outline the functionalities of a system that integrates and controls a fleet of Unmanned Aircraft Vehicles (UAVs). UAVs have a set of payload sensors employed for territorial surveillance, whose outputs are stored in the system and analysed by the data exploitation functions at different levels. In particular, we detail the second level data exploitation function whose aim is to improve the sensors data interpretation in the post-mission activities. It is concerned with the mosaicking of the aerial images and the cartography enrichment by human sensors—the social media users. We also describe the software architecture for the development of a mash-up (the integration of information and functionalities coming from the Web) and the possibility of using human sensors in the monitoring of the territory, a field in which, traditionally, the involved sensors were only the hardware ones.JRC.H.6-Digital Earth and Reference Dat

A CFD-based virtual test-rig for rotating heat exchangers

Rotating heat exchangers are used in steel industry, air conditioning and thermal power plants to pre-heat air used in steam generators or for waste heat recovery. Here we focus on a rotating heat exchanger on a so-called Ljungström arrangement operated in thermal power plants to pre-heat the air fed to the steam generators. In these devices the heat exchange between two fluids is achieved through a rotating matrix that gets in contact alternatively with the two fluid streams and acts as a thermal accumulator. To increase the heat capacity and the overall exchange surface, the rotating matrix is filled by a series of folded metal sheets. In the paper we de-scribe a methodology to account for the effects of the Ljungström in a virtual test-rig implemented in a Computational Fluid Dynamics environment. To this aim, a numerical model based on the work of Molinari and Cantiano was derived and implemented in the OpenFOAM library. RANS numerical results were compared with those of a mono-dimensional tool used by ENEL to design Ljungström heat exchangers and validated against available measurements in a real configuration of a thermal power plant

Energy consumption for data distribution in content delivery networks

A considerable percentage of worldwide electrical energy is consumed by information and communication technology. One significant element in this perspective are the data distribution systems via Content Delivery Networks (CDNs). We introduce a new model to compute the total energy consumption of CDNs which is based on a hierarchical Internet map and that takes into account the energy consumption needed to keep servers synchronized. The CDN is represented as a main server storing the whole data set and several surrogate servers, each caching a subset of the entire data set. Servers are located in a hierarchical three-tier network topology. We analyze the energy consumption trends as a function of the number of surrogate server. Results show that increasing the number of surrogate servers decreases the transmission delay but it does not always lead to decreasing energy consumption. Furthermore, the energy consumption profile as a function of the number of servers strongly depends on the ratio between the number of content requests and modifications. Finally, we show that the adoption of a hierarchical network model permits to highlight slightly different energy consumption trends with respect to those of standard “flat” network representation

Flusso caldo in abitacolo, caratterizzazione termica con la CFD

Analisi CFD per la caratterizzazione del flusso caldo all'interno di un abitacolo al fine di valutare le grandezze necessarie al calcolo dell'indice di comfort termico

Atomistic model of magnetisation dynamics and equilibrium properties of magnetic tunnel junctions

The next generation of portable devices requires random access memories (RAMs) which are characterised by high performance and at the same time low power consumption. A promising candidate as replacement in this sector is magnetic RAM (MRAM) based on CoFeB/MgO magnetic tunnel junctions, since it retains the fast operational capability while reducing the energy requirements due to its non-volatile nature. Despite such outstanding features, a complete understanding of the device operation has not been achieved yet. This limits the scaling of the device below the next technological node (< 20nm). The reduction in the number of atoms constituting these devices is responsible for surface and finite size effects as well as a reduced thermal stability, which affects the dynamic properties. Currently, micromagnetism represents the most used theoretical approach to investigate magnetic materials and their properties. The main limitation of this model is the continuum approach. In this approximation the atomic properties are averaged, which makes it unsuitable to describe interface, surface and finite size effects as well as thermal effects. Do deal with these limitations, in this thesis we use an atomistic spin model to investigate the equilibrium and dynamical properties of CoFeB/MgO-based systems, an approach more appropriate to account for such effects. Our results suggest that CoFeB/MgO systems are characterised by more complex magnetic properties than usually assumed. The reversal mechanism is non-uniform at dimensions and temperatures that are technologically relevant. Moreover, at these time scales thermal effects cause a distribution of the dynamic properties that represent an intrinsic limitation to the device reliability and need to be addressed in order to achieve the desired scaling. The results also show the importance of atomistic models to understand and accurately describe the magnetic properties of devices when they are fabricated on the nano scale

Customized multichannel measurement system for microbial fuel cell characterization

This work presents the development of an automatic and customized measuring system employing sigma-delta analog-to-digital converters and transimpedance amplifiers for precise mea- surements of voltage and current signals generated by microbial fuel cells (MFCs). The system can perform multi-step discharge protocols to accurately measure the power output of MFCs, and has been calibrated to ensure high precision and low noise measurements. One of the key features of the proposed measuring system is its ability to conduct long-term measurements with variable time steps. Moreover, it is portable and cost-effective, making it ideal for use in laboratories without sophisti- cated bench instrumentation. The system is expandable, ranging from 2 to 12 channels by adding dual-channel boards, which allows for testing of multiple MFCs simultaneously. The functionality of the system was tested using a six-channel setup, and the results demonstrated its ability to detect and distinguish current signals from different MFCs with varying output characteristics. The power measurements obtained using the system also allow for the determination of the output resistance of the MFCs being tested. Overall, the developed measuring system is a useful tool for characterizing the performance of MFCs, and can be helpful in the optimization and development of sustainable energy production technologies

Optimum dataset size and search space for minimum zone roundness evaluation by genetic algorithm

Roundness is one of the most common features in machining. The minimum zone tolerance (MZT) approach provides the minimum roundness error, i.e. the minimum distance between the two concentric reference circles containing the acquired profile; more accurate form error estimation results in less false part rejections. MZT is still an open problem and is approached here by a Genetic Algorithm. Only few authors have addressed the definition of the search space center and size and its relationship with the dataset size, which greatly influence the inspection time for the profile measurement and the convergence speed of the roundness estimation algorithm for a given target accuracy. Experimental tests on certified roundness profiles, using the profile centroid as the search space center, have shown that the search space size is related to the number of dataset points and an optimum exists, which provides a computation time reduction up to an order of magnitude

Culti orientali nella "regio IV Italiae". Testimonianze epigrafiche e indizi archeologici

In questo lavoro si prendono in considerazione i documenti epigrafici come segnali della diffusione di culti orientali nella regio IV Italiae (Samnium et Sabina). Nella prima parte si fa il punto sulla presenza di analoghi segnali nelle altre città dell Italia romana, che pongono la questione di eventuali luoghi di devozione pubblica riservati e dell integrazione o meno di questi culti nel pantheon cittadino. Nell analisi che segue, le testimonianze della regio IV sono discusse in relazione alla loro rappresentatività numerica, alla distribuzione geografica interna, ai personaggi coinvolti e alla datazione. Nel catalogo in calce al contributo, i documenti sono raccolti secondo i culti rappresentati e i centri di appartenenza

Culti orientali nella "regio IV Italiae". Testimonianze epigrafiche e indizi archeologici

In questo lavoro si prendono in considerazione i documenti epigrafici come segnali della diffusione di culti orientali nella regio IV Italiae (Samnium et Sabina). Nella prima parte si fa il punto sulla presenza di analoghi segnali nelle altre città dell Italia romana, che pongono la questione di eventuali luoghi di devozione pubblica riservati e dell integrazione o meno di questi culti nel pantheon cittadino. Nell analisi che segue, le testimonianze della regio IV sono discusse in relazione alla loro rappresentatività numerica, alla distribuzione geografica interna, ai personaggi coinvolti e alla datazione. Nel catalogo in calce al contributo, i documenti sono raccolti secondo i culti rappresentati e i centri di appartenenza