316 research outputs found

    A Real-Time Solver For Time-Optimal Control Of Omnidirectional Robots with Bounded Acceleration

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    We are interested in the problem of time-optimal control of omnidirectional robots with bounded acceleration (TOC-ORBA). While there exist approximate solutions for such robots, and exact solutions with unbounded acceleration, exact solvers to the TOC-ORBA problem have remained elusive until now. In this paper, we present a real-time solver for true time-optimal control of omnidirectional robots with bounded acceleration. We first derive the general parameterized form of the solution to the TOC-ORBA problem by application of Pontryagin's maximum principle. We then frame the boundary value problem of TOC-ORBA as an optimization problem over the parametrized control space. To overcome local minima and poor initial guesses to the optimization problem, we introduce a two-stage optimal control solver (TSOCS): The first stage computes an upper bound to the total time for the TOC-ORBA problem and holds the time constant while optimizing the parameters of the trajectory to approach the boundary value conditions. The second stage uses the parameters found by the first stage, and relaxes the constraint on the total time to solve for the parameters of the complete TOC-ORBA problem. We further implement TSOCS as a closed loop controller to overcome actuation errors on real robots in real-time. We empirically demonstrate the effectiveness of TSOCS in simulation and on real robots, showing that 1) it runs in real time, generating solutions in less than 0.5ms on average; 2) it generates faster trajectories compared to an approximate solver; and 3) it is able to solve TOC-ORBA problems with non-zero final velocities that were previously unsolvable in real-time

    Free Open Source Software for Business Intelligence

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    Free Open Source Software (FOSS) has recently grown, becoming a significant part of the IT market. We use the word “FOSS” to refer to software under a license which grants the right to access the source code and use, study, and change the software. We must not confuse FOSS with “non-commercial software”: antonyms of FOSS are “closed” and “proprietary” software. The first purpose of this paper is to maintain an unbiased position. The analysis begins with a general overview of the FOSS world and then moves focus to business intelligence: during the last years, several tools have finally entered the market, becoming actual competitors to proprietary software. Although FOSS still needs to grow, a large number of companies are already deploying or at least testing some FOSS solutions. In addition, the research world has shown interest providing several market surveys and software analyses. After illustrating the selection criteria used, the paper describes the most interesting FOSS tools for each of the following business intelligence subcategories: database management systems (DBMS), data integration tools, analytical tools and business intelligence suites. In addition, the FOSS data mining solutions RapidMiner and KNIME are evaluated and tested on a set of data. Although the two programs are not as widespread as the proprietary data mining tools, they can be considered actual competitors to the proprietary software

    Consumo de frutas y hortalizas en la actualidad.

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    Consumo de frutas y hortalizas en la actualidad.Fil: Balaban, David. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

    Automatic Sign Reading and Localization for Semantic Mapping with an Office Robot

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    Semantic mapping is the task of providing a robot with a map of its environment beyond the open, navigable space of traditional Simultaneous Localization and Mapping (SLAM) algorithms by attaching semantics to locations. The system presented in this work reads door placards to annotate the locations of offices. Whereas prior work on this system developed hand-crafted detectors, this system leverages YOLOv5 for sign detection and EAST for text recognition. Placards are localized by computing their pose from a point cloud in a RGB-D camera frame localized by a modified ORB-SLAM. Semantic mapping is accomplished in a post-processing step after robot exploration from video recording. System performance is reported in terms of the number of placards identified, the accuracy of their placement onto a SLAM map, the accuracy of the map built, and the correctness transcribed placard text

    Mosca de las riberas (Diptera: Ephydridae) asociadas a plantines de lechuga en invernaderos

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    Mosca de las riberas (Diptera: Ephydridae) asociadas a plantines de lechuga en invernaderosFil: Lietti, Marcela. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin
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