18 research outputs found
Wavelets and Optical Flow Motion Estimation
Abstract. This article describes the implementation of a simple wavelet-based opticalflow motion estimator dedicated to continuous motions such as fluid flows. The wavelet representation of the unknown velocity field is considered. This scale-space representation, associated to a simple gradient-based optimization algorithm, sets up a welldefined multiresolution framework for the optical flow estimation. Moreover, a very simple closure mechanism, approaching locally the solution by high-order polynomials, is provided by truncating the wavelet basis at fine scales. Accuracy and efficiency of the proposed method is evaluated on image sequences of turbulent fluid flows
A transformation model based on dual-tree complex wavelet transform for non-rigid registration of 3D MRI images
Individual participant data systematic reviews with meta-analyses of psychotherapies for borderline personality disorder
© 2021 BMJ Publishing Group. All rights reserved.Introduction The heterogeneity in people with borderline personality disorder (BPD) and the range of specialised psychotherapies means that people with certain BPD characteristics might benefit more or less from different types of psychotherapy. Identifying moderating characteristics of individuals is a key to refine and tailor standard treatments so they match the specificities of the individual participant. The objective of this is to improve the quality of care and the individual outcomes. We will do so by performing three systematic reviews with meta-analyses of individual participant data (IPD). The aim of these reviews is to investigate potential predictors and moderating patient characteristics on treatment outcomes for patients with BPD. Methods and analysis We performed comprehensive searches in 22 databases and trial registries up to October 6th 2020. These will be updated with a top-up search up until June 2021. Our primary meta-analytic method will be the one-stage random-effects approach. To identify predictors, we will use the one-stage model that accounts for interaction between covariates and treatment allocation. Heterogeneity in case-mix will be assessed with a membership model based on a multinomial logistic regression where study membership is the outcome. A random-effects meta-analysis is chosen to account for expected levels of heterogeneity. Ethics and dissemination The statistical analyses will be conducted on anonymised data that have already been approved by the respective ethical committees that originally assessed the included trials. The three IPD reviews will be published in high-impact factor journals and their results will be presented at international conferences and national seminars. PROSPERO registration number CRD42021210688
Large scale flows under location uncertainty: a consistent stochastic framework
International audienceUsing a classical example, the Lorenz-63 model, an original stochastic framework is applied to represent large-scale geophysical flow dynamics. Rigorously derived from a reformulated material derivative, the proposed framework encompasses several meaningful mechanisms to model geophysical flows. The slightly compressible setup , as treated in the Boussinesq approximation, brings up a stochastic transport equation for the density and other related thermo-dynamical variables. Coupled to the momentum equation through a forcing term, a resulting stochastic Lorenz-63 model is consistently derived. Based on such a reformulated model, the pertinence of this large-scale stochastic approach is demonstrated over classical eddy-viscosity based large-scale representations
The theory of aggregates
SIGLEAvailable from British Library Document Supply Centre- DSC:D42787/82 / BLDSC - British Library Document Supply CentreGBUnited Kingdo