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Université de Neuchâtel

Conditioning multiple-point statistics simulations to block data

Straubhaar, J ; Renard, Philippe ; Mariethoz, Gregoire

In: Spatial Statistics, 2016, vol. 16, p. 53-71

Multiple-points statistics (MPS) allows to generate random fields reproducing spatial statistics derived from a training image. MPS methods consist in borrowing patterns from the training set. Therefore, the simulation domain is assumed to be at the same resolution as the conceptual model, although geometrical deformations can be handled by such techniques. Whereas punctual conditioning data...

Université de Neuchâtel

Missing data simulation inside flow rate time-series using multiple-point statistics

Oriani, F ; Borghi, A ; Straubhaar, J ; Mariethoz, Grégoire ; Renard, Philippe

In: Environmental Modelling & Software, 2016, vol. 86, p. 264-276

The direct sampling (DS) multiple-point statistical technique is proposed as a non-parametric missing data simulator for hydrological flow rate time-series. The algorithm makes use of the patterns contained inside a training data set to reproduce the complexity of the missing data. The proposed setup is tested in the reconstruction of a flow rate time-series while considering several missing data...

Université de Neuchâtel

Integrating aerial geophysical data in multiple-point statistics simulations to assist groundwater flow models

Dickson, N.E.M ; Comte, J.-C ; Renard, Philippe ; Straubhaar, J ; McKinley, J.M ; Ofterdinger, U

In: Hydrogeology Journal, 2015, vol. 23, no. 5, p. 883-900

The process of accounting for heterogeneity has made significant advances in statistical research, primarily in the framework of stochastic analysis and the development of multiple-point statistics (MPS). Among MPS techniques, the direct sampling (DS) method is tested to determine its ability to delineate heterogeneity from aerial magnetics data in a regional sandstone aquifer intruded by...

Université de Neuchâtel

Simulation of braided river elevation model time series with multiple-point statistics

Pirot, Guillaume ; Straubhaar, Julien ; Renard, Philippe

In: Geomorphology, 2014, vol. 214, p. 148-156

A new method is proposed to generate successive topographies in a braided river system. Indeed, braided river morphologymodels are a key factor influencing river–aquifer interactions and have repercussions in ecosystems, flood risk or water management. It is essentially based on multivariate multiple-point statistics simulations and digital elevation models as training data sets. On the one...

Université de Neuchâtel

A practical guide to performing multiple-point statistical simulations with the Direct Sampling algorithm

Meerschman, Eef ; Pirot, Guillaume ; Mariethoz, Gregoire ; Straubhaar, Julien ; Van Meirvenne, Marc ; Renard, Philippe

In: Computers & Geosciences, 2013, vol. 52, p. 307-324

The Direct Sampling (DS) algorithm is a recently developed multiple-point statistical simulation technique. It directly scans the training image (TI) for a given data event instead of storing the training probability values in a catalogue prior to simulation. By using distances between the given data events and the TI patterns, DS allows to simulate categorical, continuous and multivariate...

Université de Neuchâtel

Three-dimensional high resolution fluvio-glacial aquifer analog - Part 2: Geostatistical modeling

Comunian, Alessandro ; Straubhaar, Julien ; Renard, Philippe ; Bayer, P.

In: Journal of Hydrology, 2011, vol. 405, no. 1, p. 10

The heterogeneity of sedimentary structures at the decimeter scale is crucial to the understanding of groundwater flow and transport. In a series of two papers, we provide a detailed analysis of a fluvio-glacial aquifer analog: the Herten site. The geological data along a series of 2D sections in a quarry, the corresponding GPR measurements, and their sedimentological interpretation are described...