Osservazioni su alcuni aspetti di carattere filosofico e giuridico nel De carne Christi, nell'Adversus Marcionem e nel De exhortatione castitatis di Tertulliano

Il punto di partenza del contributo \ue8 il De natura deorum ciceroniano, di cui si studia la presenza in diversi scritti dell\u2019Africano, raccolti per rubriche tematiche. La prima \ue8 quella della realt\ue0 della carne di Cristo (Carn 5, 8-9 ; 23, 2 ; Marc 3, 8, 2), che il Cartaginese difende come reale nella sua costituzione materiale e nelle sue funzioni (egli si avvale a questo scopo dei testi di DND 1, 92 ; 1, 48-49). In altri passaggi il nostro autore polemizza contro diverse dottrine, di origine platonica o gnostica, sostenendo la veridicit\ue0 della percezione sensoriale (Marc 4, 8, 2-3 ; ma soprattutto An 17) : in questo caso l\u2019antecedente \ue8 il testo aristotelico, che veicola le dottrine dei presocratici (De An. 3, 3, 427 a). Si giunge quindi al tema del libero arbitrio, che Tertulliano afferma a pi\uf9 riprese contro Marcione (1, 22, 8 ; 2, 6, 1) : il modello \ue8 ciceroniano (DND 3, 76-78), ma dell\u2019argomento si studia anche la ricezione, dal De Genesi ad litteram di Agostino fino a Scoto Eriugena e Girolamo Balbi. Le argomentazioni sul libero arbitrio (Cast 2, 6 ; 3, 4) tornano anche nel testo agostiniano del De libero arbitrio

Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning

Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers

State and parameters observation for accurate off-road navigation of wheeled mobile robots

Conference of IEEE International Workshop on Advanced Robotics and its Social Impacts, ARSO 2015 ; Conference Date: 30 June 2015 Through 2 July 2015; Conference Code:119926International audienceThis paper addresses the problem of accurate and reliable path following of a heavy industrial mobile robot evolving with centimetric accuracy requirement. For this purpose sliding estimation is a crucial issue, even more in off-road context with uneven and slippery terrains. So, we focus on position and sliding observers design in function of the distance covered, thus allowing to carry on maneuvers at any operational speed with constant accuracy. Furthermore, these observers are not affected by path tracking errors. Implementation in simulation demonstrates efficiency of such algorithms

Stable haptic interaction using passive and active actuators

Conference of 2013 IEEE International Conference on Robotics and Automation, ICRA 2013 ; Conference Date: 6 May 2013 Through 10 May 2013; Conference Code:100673International audienceThis paper presents a stable control method for a hybrid haptic device comprising a brake and a motor. A review of stability condition via describing function analysis is first presented. The results show that while brakes are intrinsically stable, an active device is limited in terms of stiffness. The stability is however improved if the brake simulates a physical damping. Subsequently, the stability condition is obtained via passivity condition analysis. The results demonstrate that the stiffness is improved by engaging both actuators to create resistive forces and the passivity is respected assuming a passive virtual environment. An energy and a stiffness-bounding algorithms have been developed in order to assure the stability of the coupled system in this case. It has been tested and validated using a 1-DOF hybrid haptic device by the simulation of an unstable and an active virtual environments respectively. Experimental results show that the displayable stiffness is improved under stability conditions using the control method. Furthermore, it allows the hybrid system to simulate nonlinear and unstable virtual environments and the controller remains independent of the virtual environment model

Humanoid push recovery control in case of multiple non-coplanar contacts

Conference of 2013 26th IEEE/RSJ International Conference on Intelligent Robots and Systems: New Horizon, IROS 2013 ; Conference Date: 3 November 2013 Through 8 November 2013; Conference Code:102443International audienceThis paper presents a method for humanoid push recovery in the general context of multiple non-coplanar contacts. The method consists of a controller that minimizes the kinetic energy of a perturbed whole body humanoid system, while controlling the support change to achieve the stabilization (or push recovery) of the system. The controller uses a simple model based approach to determine the necessity of support change and in this case to approximate a new contact position that allows to stabilize the system. The controller is tested on a simulated humanoid robot and it succeeds in stabilizing the robot in coplanar and non-coplanar environments

Intrinsic tactile sensing system design for robotics manipulation

Conference of 16th IEEE-RAS International Conference on Humanoid Robots, Humanoids 2016 ; Conference Date: 15 November 2016 Through 17 November 2016; Conference Code:125717International audienceThis paper presents an intrinsic tactile sensing system designed to be implemented in a robotic anthropomorphic finger, and to fulfill most of tactile sensing characteristics required to achieve dexterous manipulation of objects. The system consists of an array of four 3-axis force sensors linked to a rigid frame with a soft non-planar surface. The paper deals with the design, construction, mathematical modeling, calibration and testing of the system. The tests show high accuracy in the estimation of contact point and force components

Perceptual Evaluation of the Passive/Active Torque and Stiffness Asymmetry of a Hybrid Haptic Device

Conference of 9th International Conference on Haptics: Neuroscience, Devices, Modeling, and Applications, EuroHaptics 2014 ; Conference Date: 24 June 2014 Through 26 June 2014; Conference Code:110079International audienceHybrid haptic interfaces combining brakes and motors can present dissimilar torque and stiffness capabilities when dissipating or restoring energy. This paper aims at identifying the asymmetry thresholds that lead to an alteration in the perception of elasticity simulated by such devices. 17 subjects took part in an experiment consisting in interacting with virtual springs with either controllable stiffness or torque asymmetry levels, and identifying if the springs were symmetric or not. Experimental results indicate that when the decompression stiffness or torque were less than 80% and 60% of the compression stiffness or torque respectively, users did not perceive the asymmetry in 80% of trials. This suggests that hybrid devices can present dissimilar active/passive torque or stiffness capabilities without affecting the perception of elasticity