The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Bruno Tisseyre - One of the best experts on this subject based on the ideXlab platform.

  • An Optimisation-based approach to generate interpretable within-field zones
    Precision Agriculture, 2019
    Co-Authors: Patrice Loisel, Brigitte Charnomordic, Hazaël Jones, Bruno Tisseyre
    Abstract:

    The paper proposes a numerical criterion to evaluate zoning quality for a given number of classes. The originality of the criterion is to simultaneously quantify how zones are heterogeneous on the whole field under study and how neighbouring zones are similar. This approach allows comparison between maps either with different zones or different labels, which is of importance for zone delineation algorithms aiming at maximizing inter-zone variability. In addition, this study also proposes an Optimisation Procedure that yields interpretable within-field zones in which each zone is assigned a clear label. The zoning Procedure involves contour delineation based on quantile values. The key point of the paper is to use the proposed numerical zoning quality criterion to guide the Optimisation Procedure showing the complementarity of both proposals in delineating relevant within-field zones. In order to demonstrate the relevancy of the criterion, the zoning Procedure and the implementation of both together, the method was tested on 50 theoretical fields with known variability and known spatial structure. A real plot with yield monitoring data was also used to demonstrate the value of the approach on a real case. Results show the relevancy of the methodology to compare maps with different zones and to sort them. Results also demonstrate the interest of the Optimisation Procedure to provide a ranked set of possible maps with different within-field zones. This set of relevant maps may constitute a decision support for practitioners who may consider additional expert information to choose the most appropriate map in the specific conditions under consideration.

Giorgio De Pasquale - One of the best experts on this subject based on the ideXlab platform.

  • Multi-scale shape Optimisation of lattice structures: an evolutionary-based approach
    International Journal on Interactive Design and Manufacturing (IJIDeM), 2019
    Co-Authors: Giulia Bertolino, Marco Montemurro, Giorgio De Pasquale
    Abstract:

    This study deals with the problem of the least-weight design of a lattice structure subject to constraints of different nature. To face this problem, a general multi-scale Optimisation Procedure is proposed. This approach aims at optimising both global and local geometric parameters defining the shape of the representative volume element of the lattice at the mesoscopic scale. The Optimisation Procedure involves design requirements defined at different scales: geometric and manufacturing constraints are involved at the mesoscopic scale, whilst thermodynamic constraints on the positive definiteness of the stiffness tensor of the lattice (modelled as an equivalent homogeneous anisotropic medium) intervene at the macroscopic scale. Finally, since lattice structures usually undergo compressive loads, a requirement on the first local buckling load is considered too. The proposed approach is based on (a) the non-uniform rational basis splines curves theory to describe the shape of the struts composing the lattice, (b) the strain energy homogenisation technique of periodic media to perform the scale transition and (c) a special genetic algorithm to perform Optimisation calculations. The optimised solutions provided by the presented method are characterised by a weight saving of about $$39\%$$ 39 % with slightly enhanced mechanical properties when compared to conventional octahedral lattice structures.

  • Multi-scale shape Optimisation of lattice structures: an evolutionary-based approach.
    International Journal on Interactive Design and Manufacturing (IJIDeM), 2019
    Co-Authors: Giulia Bertolino, Marco Montemurro, Giorgio De Pasquale
    Abstract:

    This study deals with the problem of the least-weight design of a lattice structure subject to constraints of different nature. To face this problem, a general multi-scale Optimisation Procedure is proposed. This approach aims at optimising simultaneously both global and local geometric parameters defining the shape of the representative volume element (RVE) of the lattice at the mesoscopic scale. The Optimisation Procedure involves design requirements defined at different scales: geometric and manufacturing constraints are involved at the mesoscopic scale, whilst thermodynamic constraints on the positive definiteness of the stiffness tensor of the lattice (modelled as an equivalent homogeneous anisotropic medium) intervene at the macroscopic scale. Finally, since lattice structures usually undergo compressive loads, a requirement on the first local buckling load is considered too. The proposed approach is based on (a) the Non-Uniform Rational Basis Splines (NURBS) curves theory to describe the shape of the struts composing the lattice, (b) the strain energy homogenisation technique of periodic media to perform the scale transition and (c) a special genetic algorithm to perform Optimisation calculations. The optimised solutions provided by the presented method are characterised by a weight saving of about 39% with slightly enhanced mechanical properties when compared to conventional octahedral lattice structures.

Patrice Loisel - One of the best experts on this subject based on the ideXlab platform.

  • An Optimisation-based approach to generate interpretable within-field zones
    Precision Agriculture, 2019
    Co-Authors: Patrice Loisel, Brigitte Charnomordic, Hazaël Jones, Bruno Tisseyre
    Abstract:

    The paper proposes a numerical criterion to evaluate zoning quality for a given number of classes. The originality of the criterion is to simultaneously quantify how zones are heterogeneous on the whole field under study and how neighbouring zones are similar. This approach allows comparison between maps either with different zones or different labels, which is of importance for zone delineation algorithms aiming at maximizing inter-zone variability. In addition, this study also proposes an Optimisation Procedure that yields interpretable within-field zones in which each zone is assigned a clear label. The zoning Procedure involves contour delineation based on quantile values. The key point of the paper is to use the proposed numerical zoning quality criterion to guide the Optimisation Procedure showing the complementarity of both proposals in delineating relevant within-field zones. In order to demonstrate the relevancy of the criterion, the zoning Procedure and the implementation of both together, the method was tested on 50 theoretical fields with known variability and known spatial structure. A real plot with yield monitoring data was also used to demonstrate the value of the approach on a real case. Results show the relevancy of the methodology to compare maps with different zones and to sort them. Results also demonstrate the interest of the Optimisation Procedure to provide a ranked set of possible maps with different within-field zones. This set of relevant maps may constitute a decision support for practitioners who may consider additional expert information to choose the most appropriate map in the specific conditions under consideration.

Giulia Bertolino - One of the best experts on this subject based on the ideXlab platform.

  • Multi-scale shape Optimisation of lattice structures: an evolutionary-based approach
    International Journal on Interactive Design and Manufacturing (IJIDeM), 2019
    Co-Authors: Giulia Bertolino, Marco Montemurro, Giorgio De Pasquale
    Abstract:

    This study deals with the problem of the least-weight design of a lattice structure subject to constraints of different nature. To face this problem, a general multi-scale Optimisation Procedure is proposed. This approach aims at optimising both global and local geometric parameters defining the shape of the representative volume element of the lattice at the mesoscopic scale. The Optimisation Procedure involves design requirements defined at different scales: geometric and manufacturing constraints are involved at the mesoscopic scale, whilst thermodynamic constraints on the positive definiteness of the stiffness tensor of the lattice (modelled as an equivalent homogeneous anisotropic medium) intervene at the macroscopic scale. Finally, since lattice structures usually undergo compressive loads, a requirement on the first local buckling load is considered too. The proposed approach is based on (a) the non-uniform rational basis splines curves theory to describe the shape of the struts composing the lattice, (b) the strain energy homogenisation technique of periodic media to perform the scale transition and (c) a special genetic algorithm to perform Optimisation calculations. The optimised solutions provided by the presented method are characterised by a weight saving of about $$39\%$$ 39 % with slightly enhanced mechanical properties when compared to conventional octahedral lattice structures.

  • Multi-scale shape Optimisation of lattice structures: an evolutionary-based approach.
    International Journal on Interactive Design and Manufacturing (IJIDeM), 2019
    Co-Authors: Giulia Bertolino, Marco Montemurro, Giorgio De Pasquale
    Abstract:

    This study deals with the problem of the least-weight design of a lattice structure subject to constraints of different nature. To face this problem, a general multi-scale Optimisation Procedure is proposed. This approach aims at optimising simultaneously both global and local geometric parameters defining the shape of the representative volume element (RVE) of the lattice at the mesoscopic scale. The Optimisation Procedure involves design requirements defined at different scales: geometric and manufacturing constraints are involved at the mesoscopic scale, whilst thermodynamic constraints on the positive definiteness of the stiffness tensor of the lattice (modelled as an equivalent homogeneous anisotropic medium) intervene at the macroscopic scale. Finally, since lattice structures usually undergo compressive loads, a requirement on the first local buckling load is considered too. The proposed approach is based on (a) the Non-Uniform Rational Basis Splines (NURBS) curves theory to describe the shape of the struts composing the lattice, (b) the strain energy homogenisation technique of periodic media to perform the scale transition and (c) a special genetic algorithm to perform Optimisation calculations. The optimised solutions provided by the presented method are characterised by a weight saving of about 39% with slightly enhanced mechanical properties when compared to conventional octahedral lattice structures.

Crystal S. Stonesifer - One of the best experts on this subject based on the ideXlab platform.

  • A simulation and Optimisation Procedure to model daily suppression resource transfers during a fire season in Colorado
    International Journal of Wildland Fire, 2017
    Co-Authors: Yu Wei, Erin J. Belval, David E. Calkin, Matthew P. Thompson, Crystal S. Stonesifer
    Abstract:

    Sharing fire engines and crews between fire suppression dispatch zones may help improve the utilisation of fire suppression resources. Using the Resource Ordering and Status System, the Predictive Services' Fire Potential Outlooks and the Rocky Mountain Region Preparedness Levels from 2010 to 2013, we tested a simulation and Optimisation Procedure to transfer crews and engines between dispatch zones in Colorado (central United States) and into Colorado from out-of-state. We used this model to examine how resource transfers may be influenced by assignment shift length, resource demand prediction accuracy, resource drawdown restrictions and the compounding effects of resource shortages. Test results show that, in certain years, shortening the crew shift length from 14 days to 4 days doubles the yearly transport cost. Results also show that improving the accuracy in predicting daily resource demands decreases the engine and crew transport costs by up to 40%. Other test results show that relaxing resource drawdown restrictions could decrease resource transport costs and the reliance on out-of-state resources. The model-suggested assignments result in lower transport costs than did historical assignments.