4 research outputs found
Solving constrained Procrustes problems: a conic optimization approach
Procrustes problems are matrix approximation problems searching for
a~transformation of the given dataset to fit another dataset. They find
applications in numerous areas, such as factor and multivariate analysis,
computer vision, multidimensional scaling or finance. The known methods for
solving Procrustes problems have been designed to handle specific sub-classes,
where the set of feasible solutions has a special structure (e.g. a Stiefel
manifold), and the objective function is defined using a specific matrix norm
(typically the Frobenius norm). We show that a wide class of Procrustes
problems can be formulated and solved as a (rank-constrained) semi-definite
program. This includes balanced and unbalanced (weighted) Procrustes problems,
possibly to a partially specified target, but also oblique, projection or
two-sided Procrustes problems. The proposed approach can handle additional
linear, quadratic, or semi-definite constraints and the objective function
defined using the Frobenius norm but also standard operator norms. The results
are demonstrated on a set of numerical experiments and also on real
applications
A unified approach to radial, hyperbolic, and directional distance models in Data Envelopment Analysis
The paper analyzes properties of a large class of "path-based" Data
Envelopment Analysis models through a unifying general scheme, which includes
as standard the well-known oriented radial models, the hyperbolic distance
measure model, and the directional distance measure models. The scheme also
accommodates variants of standard models over negative data. Path-based models
are analyzed from the point of view of nine desired properties that a
well-designed model should satisfy. The paper develops mathematical tools that
allow systematic investigation of these properties in the general scheme
including, but not limited to, the standard path-based models. Among other
results, the analysis confirms the generally accepted view that path-based
models need not generate Pareto--Koopmans efficient projections, one-to-one
identification, or strict monotonicity