PMID- 28957024 OWN - NLM STAT- PubMed-not-MEDLINE DCOM- 20181218 LR - 20181218 IS - 1530-888X (Electronic) IS - 0899-7667 (Linking) VI - 29 IP - 11 DP - 2017 Nov TI - Sparse Covariance Matrix Estimation by DCA-Based Algorithms. PG - 3040-3077 LID - 10.1162/neco_a_01012 [doi] AB - This letter proposes a novel approach using the [Formula: see text]-norm regularization for the sparse covariance matrix estimation (SCME) problem. The objective function of SCME problem is composed of a nonconvex part and the [Formula: see text] term, which is discontinuous and difficult to tackle. Appropriate DC (difference of convex functions) approximations of [Formula: see text]-norm are used that result in approximation SCME problems that are still nonconvex. DC programming and DCA (DC algorithm), powerful tools in nonconvex programming framework, are investigated. Two DC formulations are proposed and corresponding DCA schemes developed. Two applications of the SCME problem that are considered are classification via sparse quadratic discriminant analysis and portfolio optimization. A careful empirical experiment is performed through simulated and real data sets to study the performance of the proposed algorithms. Numerical results showed their efficiency and their superiority compared with seven state-of-the-art methods. FAU - Phan, Duy Nhat AU - Phan DN AD - Laboratory of Theoretical and Applied Computer Science EA 3097, University of Lorraine, Ile du Saulcy, 57045 Metz, France duy-nhat.phan@univ-loraine.fr. FAU - Le Thi, Hoai An AU - Le Thi HA AD - Laboratory of Theoretical and Applied Computer Science EA 3097, University of Lorraine, Ile du Saulcy, 57045 Metz, France hoai-an.le-thi@univ-lorraine.fr. FAU - Dinh, Tao Pham AU - Dinh TP AD - Laboratory of Mathematics, INSA-Rouen, University of Normandie, 76801 Saint-Etienne-du-Rouvray cedex, France pham@insa-rouen.fr. LA - eng PT - Journal Article DEP - 20170928 PL - United States TA - Neural Comput JT - Neural computation JID - 9426182 EDAT- 2017/09/29 06:00 MHDA- 2017/09/29 06:01 CRDT- 2017/09/29 06:00 PHST- 2017/09/29 06:00 [pubmed] PHST- 2017/09/29 06:01 [medline] PHST- 2017/09/29 06:00 [entrez] AID - 10.1162/neco_a_01012 [doi] PST - ppublish SO - Neural Comput. 2017 Nov;29(11):3040-3077. doi: 10.1162/neco_a_01012. Epub 2017 Sep 28.