1,721,241 research outputs found
I costi socio-sanitari dell’insufficienza renale cronica
No full textWE AIMED TO ESTIMATE THE SOCIO ECONOMIC COSTS OF CHRONIC KIDNEY FAILURE IN ITALIAN REGION
Teams of Robots for Underwater Archaeology: the ARROWS project
No full textARROWS is the acronym for Archaeological RObot systems for the World’s Seas. The project, started in September 2012, is funded by the EU in the framework of the FP7 call ENV-2012, challenge 6.2-6, devoted to “Development of advanced technologies and tools for mapping, diagnosing, excavating, and securing underwater and coastal archaeological sites”. The ARROWS consortium comprises expertise from underwater archaeology, underwater engineering,
robotics, image processing and recognition from academia and industry. 10 partners from 5 different Countries are involved
An Attitude Estimation Algorithm for Mobile Robots under Unknown Magnetic Disturbances
Full text linkAttitude estimation is a crucial aspect for navigation and motion control of autonomous vehicles. This concept is particularly true in the case of unavailability of localization sensors when navigation and control rely on dead reckoning strategies; in this case, indeed, the orientation estimate is also used along with speed measurements to update the position estimate. Among the different approaches proposed in the literature, the de facto state of the art in this field is represented by nonlinear complementary filters: they fuse the measurements of angular rate obtained through gyroscopes, and a measurement of gravity and Earth's magnetic field vectors respectively obtained through accelerometers and magnetometers. This paper is focused on an attitude estimation strategy for autonomous underwater vehicles (AUV). The proposed novelty includes the identification of some critical issues that arise when AUV attitude estimation algorithms are applied in practice. They are mainly due to the use of low-accuracy low-cost microelectromechanical systems (MEMS) sensors and on different sources of magnetic disturbances. Some strategies to overcome the identified issues are proposed, including the integration of a single-axis fiber optic gyroscope (FOG) that ensures a considerable performance improvement with a moderate cost increase. The proposed strategies for detection of issues and sensor fusion have been experimentally tested and validated in a real application scenario estimating the attitude of an AUV performing a lawn mower path. The expected performance improvement is confirmed; the obtained results are described and analyzed in this paper
La Città del Futuro. Roma 2030 l’architettura come risorsa
No full textVisioni per la città del futuro. Roma 2030: l'architettura come risorsa Le città tornano ad essere protagoniste del nostro futuro. Il XXI secolo sarà un secolo urbano. Si stima che dal 2015 al 2025 la popolazione urbanizzata al mondo crescerà di 65 milioni di abitanti l’anno e che, nel 2050, il 55% della ricchezza mondiale sarà concentrata in sole 600 metropoli. Si deve tornare ad investire sul futuro delle città: non solo le dinamiche che derivano dalla globalizzazione e dalla finanziarizzazione dell’economia hanno da tempo modificato lo scenario dello sviluppo, ma digitalizzazione (terza rivoluzione delle macchine), cambiamento climatico e inquinamento, questione energetica e polarizzazione sociale stanno delineando nuove dinamiche di trasformazione che vedono le città cuore del cambiamento. La fase di transizione che stiamo vivendo è molto delicata, fenomeni epocali stanno modificando le nostre società, le nostre economie, il nostro ambiente. C’è un reale bisogno di fondere il dinamismo economico con politiche e investimenti in grado di affrontare i limiti ambientali, economici, culturali e sociali. Le città del mondo, per affrontare le nuove sfide, tornano a disegnare il loro futuro nella crescente trasformazione urbana pianificando interventi e investimenti sulla base di una visione a dieci, venti, trent’anni; si fissano così i contenuti di una nuova fase urbana fatta di crescita, digitalizzazione, resilienza ai cambiamenti climatici
A Dynamic Manipulation Strategy for an Intervention Autonomous Underwater Vehicle
Full text linkThis paper presents the modelling and the control architecture of an Autonomous Underwater Vehicle for
Intervention (I-AUV). Autonomous underwater manipulation with free-floating base is still an open topic of research,
far from reaching an industrial product. Dynamic manipulation tasks, where relevant vehicle velocities are required
during manipulation, over an additional challenge. In this paper, the accurate modelling of an I-AUV is described,
not neglecting the interaction with the fluid. A grasp planning strategy is proposed and integrated in the control
of the whole system. The performances of the I-AUV have been analysed by means of simulations of a dynamic
manipulation task
Single axis FOG aided attitude estimation algorithm for mobile robots
No full textThis paper is focused on an attitude estimation method for Autonomous Underwater Vehicles (AUVs).
Data acquired by a commercial Micro-Electro-Mechanical Systems (MEMS) Inertial Measurement Unit
(IMU), equipped with magnetometers, and a Fibre Optic Gyroscope (FOG) are fused to estimate the
attitude of the vehicle. One of the most used attitude estimation filter, a Nonlinear Complementary
Filter (NCF), is proposed as the basis of this work; then, some adaptations to the original formulation of
the filter are illustrated to better suit it to the field of underwater robotics. The proposed improvements
include the online tuning of the gains of the filter to cope with sensor disturbances and the employment
of the data acquired by a FOG. In addition, a fast procedure for the calibration of a magnetometer
is introduced to increase the reliability of its readings. The resulting filter is used to estimate the
attitude of an AUV; the performances of the proposed solution are tested and evaluated, in particular
when unpredictable magnetic disturbances are present, highlighting the improvements that the applied
changes allow to achieve in the specific field of application
Simultaneous navigation state and sea current estimation through augmented state Unscented Kalman Filter
No full textAn Unscented Kalman Filter (UKF) to simultaneously estimate the navigation state of an Autonomous Underwater Vehicle (AUV) and the sea current, a priori unknown, is proposed. The filter is the result of a modification of an UKF developed in the past by the authors for the sole purpose of navigation state estimation. The new algorithm has been obtained by integrating the vehicle model with a contribution due to a constant sea current and by augmenting the state vector dimension including the North and the East components of the current itself. The resulting algorithm has been validated offline exploiting the signals of the Typhoon AUV on-board sensors collected during a sea experimental campaign
Identification of the main hydrodynamic parameters of Typhoon AUV from a reduced experimental dataset
Full text linkIn this research work a case study dealing with the identification of the main hydrodynamic properties of an Autonomous Underwater Vehicle (AUV) is presented. The vehicle is the Typhoon-class AUV developed by the Department of Industrial Engineering of the University of Florence, Italy. The identification of the main hull hydrodynamic parameters is very important for the tuning of an accurate dynamic model of the vehicle, which could be used for several purposes including the development of model based localization and navigation filters. The authors describe the simplified identification procedure adopted for the Typhoon AUV starting from a reduced experimental dataset obtained during some missions at sea performed in 2014 in Biograd na Moru, Croatia
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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