1,720,968 research outputs found
Un’esperienza di educazione ambientale nella scuola media di secondo grado. Il progetto:”Stiamo cercando di costruire un buon rapporto con l’ozonosfera"
No full textOptimal design of robotic work-cell through hierarchical manipulability maximization
No full textThe increasing requests for flexible robotic applications involving the rapid relocation of the robot manipulator, possibly mounted on a mobile base, imposes tolerance to imprecise positioning. The high manipulability of the nominally designed poses, i.e., the capacity to change the position and the orientation of a given robot joint configuration's end-effector, is often considered a proxy for robustness to imprecise positioning. This work presents a method for choosing target end-effector poses to manipulate bulky objects in complex environments. The paper proposes a two-layer optimizer connected in cascade to maximize the manipulability and achieve reasonable computational time. First, using a genetic algorithm (GA) allows a global search for a satisfactory solution to the target poses of the task at the same time. Subsequently, the output of the GA becomes the initial guess for the simulated annealing (SA) algorithm, which locally maximizes each pose's manipulability separately. The feasibility of the connecting trajectories and collisions are checked in both layers. Experiments show the method's ability to find excellent solutions within a limited time, considering a complex problem involving manipulating large objects in a cluttered environment. The simulations of three working scenarios allowed testing of the proposed method. The final validation of the algorithm was on two relevant industrial use-cases: the manipulation of sidewalls and the manipulation of cargo panels inside an aircraft fuselage
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
Optimal task positioning in multi-robot cells, using nested meta-heuristic swarm algorithms
No full textProcess planning of multi-robot cells is usually a manual and time consuming activity, based on trials-and-errors. A co-manipulation problem is analysed, where one robot handles the work-piece and one robot performs a task on it and a method to find the optimal pose of the work-piece is proposed. The method, based on a combination of Whale Optimization Algorithm and Ant Colony Optimization algorithm, minimize a performance index while taking into account technological and kinematics constraints. The index evaluates process accuracy considering transmission elasticity, backslashes and distance from joint limits. Numerical simulations demonstrate the method robustness and convergence
Sim-to-Real RNN-Based Framework for the Precise Positioning of Autonomous Mobile Robots
No full textThis work proposes a recurrent neural network-based sim-to-real method to learn mobile robot localization using lidar data in dynamic environments. The main aim of the algorithm is to estimate a Cartesian position error relative to a saved position by means of stored lidar readings in a two-dimensional environment, using lidar data as input. To achieve this, we propose a method that first trains a model on synthetic and augmented LiDAR data to embed rigid transformations into the deep learning model and then fine-tunes the model on real positions using real-world data and external camera measures to produce training labels. This pre-training and fine-tuning approach considerably reduces the time, the computation power, and the amount of real-world data needed to have an accurate model, allowing running the fine-positioning model on the edge of autonomous mobile robots(AMRs). After optimizing the model architecture and hyperparameters, the devised model is tested in different scenarios, comparing the precise positioning capability of AMRs with that of a classical iterative closest point and advanced Monte Carlo localization
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
Towards optimal task positioning in multi-robot cells, using nested meta-heuristic swarm algorithms
No full textWhile multi-robot cells are being used more often in industry, the problem of work-piece position optimization is still solved using heuristics and the human experience and, in most industrial cases, even a feasible solution takes a considerable amount of trials to be found. Indeed, the optimization of a generic performance index along a path is complex, due to the dimension of the feasible-configuration space. This work faces this challenge by proposing an iterative layered-optimization method that integrates a Whale Optimization and an Ant Colony Optimization algorithm, the method allows the optimization of a user-defined objective function, along a working path, in order to achieve a quasi-optimal, collision free solution in the feasible-configuration space
Stiamo cercando di costruire un buon rapporto con l’ozonosfera: un progetto di educazione ambientale nella scuola media di secondo grado
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