1,721,736 research outputs found
La sentenza Banca Popolare di Bari S.p.A c. Commissione europea: brevi note in tema di prescrizione dell’azione per responsabilità extracontrattuale dell’Unione
Full text linkIl contributo affronta il tema dell’individuazione del momento a partire dal quale inizia a decorrere il termine di prescrizione dell’azione per responsabilità extracontrattuale dell'Unione, in funzione delle caratteristiche temporali dei danni fatti valere in giudizio
Nuova direttiva Copyright e filtraggio dei contenuti protetti: il gioco di sponda della Corte in Polonia c. Parlamento e Consiglio, 22 giugno 2022
No full textIl contributo analizza la sentenza Polonia c. Parlamento europeo e Consiglio, della Corte di giustizia nell'Unione europea, nel quadro della disciplina di riforma del diritto d'autore a livello UE, oltre che alla luce dell'evoluzione del mercato unico digitale. In particolare, il lavoro indaga i profili più pertinenti al bilanciamento tra diritti fondamentali rilevanti, muovendo dal contemperamento effettuato dal legislatore dell'Unione
Computing fast search heuristics for physics-based mobile robot motion planning
Full text linkMobile robots are increasingly being employed to assist responders in search and rescue missions. Robots have to navigate in dangerous areas such as collapsed buildings and hazardous sites, which can be inaccessible to humans. Tele-operating the robots can be stressing for the human operators, which are also overloaded with mission tasks and coordination overhead, so it is important to provide the robot with some degree of autonomy, to lighten up the task for the human operator and also to ensure robot safety.
Moving robots around requires reasoning, including interpretation of the environment, spatial reasoning, planning of actions (motion), and execution. This is particularly challenging when the environment is unstructured, and the terrain is \textit{harsh}, i.e. not flat and cluttered with obstacles.
Approaches reducing the problem to a 2D path planning problem fall short, and many of those who reason about the problem in 3D don't do it in a complete and exhaustive manner.
The approach proposed in this thesis is to use rigid body simulation to obtain a more truthful model of the reality, i.e. of the interaction between the robot and the environment. Such a simulation obeys the laws of physics, takes into account the geometry of the environment, the geometry of the robot, and any dynamic constraints that may be in place.
The physics-based motion planning approach by itself is also highly intractable due to the computational load required to perform state propagation combined with the exponential blowup of planning; additionally, there are more technical limitations that disallow us to use things such as state sampling or state steering, which are known to be effective in solving the problem in simpler domains.
The proposed solution to this problem is to compute heuristics that can bias the search towards the goal, so as to quickly converge towards the solution.
With such a model, the search space is a rich space, which can only contain states which are physically reachable by the robot, and also tells us enough information about the safety of the robot itself.
The overall result is that by using this framework the robot engineer has a simpler job of encoding the \textit{domain knowledge} which now consists only of providing the robot geometric model plus any constraints
Dynamic obstacles detection and 3D map updating
No full textWe present a real time method for updating a 3D map with dynamic obstacles detection. Moving obstacles are detected through ray-casting on spherical voxelization of point clouds. We evaluate the accuracy of this method on a point cloud dataset, suitably constructed for testing ray-surface intersection under relative motion conditions. Moreover, we show the benefits of the map updating in a real robot equipped with a rotating LIDAR system, navigating in real world scenarios, populated by moving people
Adaptive Robust Three-dimensional Trajectory Tracking for Actively Articulated Tracked Vehicles
No full textA new approach is proposed for an adaptive robust three-dimensional (3D) trajectory-tracking controller design.
The controller is modeled for actively articulated tracked vehicles (AATVs). These vehicles have active subtracks,
called flippers, linked to the ends of the main tracks, to extend the locomotion capabilities in hazardous
environments, such as rescue scenarios. The proposed controller adapts the flippers configuration and simultaneously
generates the track velocities, to allow the vehicle to autonomously follow a given feasible 3D path.
The approach develops both a direct and differential kinematic model of the AATV for traversal task execution
correlating the robot body motion to the flippers motion. The benefit of this approach is to allow the controller
to flexibly manage all the degrees of freedom of the AATV as well as the steering. The differential kinematic
model integrates a differential drive robot model, compensating the slippage between the vehicle tracks and the
traversed terrain. The underlying feedback control law dynamically accounts for the kinematic singularities of
the mechanical vehicle structure. The designed controller integrates a strategy selector too, which has the role of
locally modifying the rail path of the flipper end points. This serves to reduce both the effort of the flipper servo
motors and the traction force on the robot body, recognizing when the robot is moving on a horizontal plane
surface. Several experiments have been performed, in both virtual and real scenarios, to validate the designed
trajectory-tracking controller, while the AATV negotiates rubble, stairs, and complex terrain surfaces. Results
are compared with both the performance of an alternative control strategy and the ability of skilled human
operators, manually controlling the actively articulated components of the robot
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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