54 research outputs found

    Fish behavior and its use in the capture and culture of fishes

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    Fishery management, Behaviour, Food fish, Fish culture, Conferences

    Neural Learning of Vector Fields for Encoding Stable Dynamical Systems

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    Lemme A, Reinhart F, Neumann K, Steil JJ. Neural Learning of Vector Fields for Encoding Stable Dynamical Systems. Neurocomputing. 2014;141:3-14

    Overview of the JET results in support to ITER

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    Incremental bootstrapping of parameterized motor skills

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    Many motor skills have an intrinsic, low-dimensional parameterization, e.g. reaching through a grid to different targets. Repeated policy search for new parameterizations of such a skill is inefficient, because the structure of the skill variability is not exploited. This issue has been previously addressed by learning mappings from task parameters to policy parameters. In this work, we introduce a bootstrapping technique that establishes such parameterized skills incrementally. The approach combines iterative learning with state-of-the-art black-box policy optimization. We investigate the benefits of incrementally learning parameterized skills for efficient policy retrieval and show that the number of required rollouts can be significantly reduced when optimizing policies for novel tasks. The approach is demonstrated for several parameterized motor tasks including upper-body reaching motion generation for the humanoid robot COMAN

    Hybrid Analytical and Data-Driven Modeling for Feed-Forward Robot Control

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    Feed-forward model-based control relies on models of the controlled plant, e.g., in robotics on accurate knowledge of manipulator kinematics or dynamics. However, mechanical and analytical models do not capture all aspects of a plant's intrinsic properties and there remain unmodeled dynamics due to varying parameters, unmodeled friction or soft materials. In this context, machine learning is an alternative suitable technique to extract non-linear plant models from data. However, fully data-based models suffer from inaccuracies as well and are inefficient if they include learning of well known analytical models. This paper thus argues that feed-forward control based on hybrid models comprising an analytical model and a learned error model can significantly improve modeling accuracy. Hybrid modeling here serves the purpose to combine the best of the two modeling worlds. The hybrid modeling methodology is described and the approach is demonstrated for two typical problems in robotics, i.e., inverse kinematics control and computed torque control. The former is performed for a redundant soft robot and the latter for a rigid industrial robot with redundant degrees of freedom, where a complete analytical model is not available for any of the platforms

    Modelling of parametrized processes via regression in the model space of neural networks

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    We consider the modelling of parametrized processes, where the goal is to model the process for new parameter value combinations. We compare the classical regression approach to a modular approach based on regression in the model space: First, for each process parametrization a model is learned. Second, a mapping from process parameters to model parameters is learned. We evaluate both approaches on two synthetic and two real-world data sets and show the advantages of the regression in the model space

    Thermal energy storage with phase change materials (PCMs) for the improvement of the energy performance of buildings

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    Main Goals: - To evaluate how PCMs can be used to improve the energy performance of different typologies of residential buildings (lightweight steel-framed and heavyweight constructions) in different climates; -To develop a methodology for the dynamic simulation of energy in buildings considering the influence of latent heat from the phase change processes; - To develop a methodology for the assessment of the heat transfer through small thermal energy storage (TES) units to be used in the design of new construction solutions
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