Image Restoration with Discrete Constrained Total Variation Part I: Fast and Exact Optimization
Journal of Mathematical Imaging and Vision
Archimedean copula estimation using Bayesian splines smoothing techniques
Computational Statistics & Data Analysis
Linear B-spline copulas with applications to nonparametric estimation of copulas
Computational Statistics & Data Analysis
Thresholding methods to estimate copula density
Journal of Multivariate Analysis
The Split Bregman Method for L1-Regularized Problems
SIAM Journal on Imaging Sciences
Parametric Maximum Flow Algorithms for Fast Total Variation Minimization
SIAM Journal on Scientific Computing
Moment-independent regional sensitivity analysis: Application to an environmental model
Environmental Modelling & Software
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A copula density is the joint probability density function (PDF) of a random vector with uniform marginals. An approach to bivariate copula density estimation is introduced that is based on maximum penalized likelihood estimation (MPLE) with a total variation (TV) penalty term. The marginal unity and symmetry constraints for copula density are enforced by linear equality constraints. The TV-MPLE subject to linear equality constraints is solved by an augmented Lagrangian and operator-splitting algorithm. It offers an order of magnitude improvement in computational efficiency over another TV-MPLE method without constraints solved by the log-barrier method for the second order cone program. A data-driven selection of the regularization parameter is through K-fold cross-validation (CV). Simulation and real data application show the effectiveness of the proposed approach. The MATLAB code implementing the methodology is available online.