Geometric optimisation algorithms are developed that efficiently find the nearest low-rank correlation matrix. We show, in numerical tests, that our methods compare favourably to the existing methods in the literature. The connection with the Lagrange multiplier method is established, along with...

We analyze the technical efficiency of German and Swiss urban public transport companies by means of SFA. In transport networks we might face different network structures or complexities, not observed, but influencing the production process. The unobserved factors are typically modeled as...

A nonparametric Data Envelopment Analysis (DEA) is performed on hospitals in the federal state of Saxony (Germany) and in Switzerland. This study is of interest from three points of view. First, contrary to most existing work, patient days are not treated as an output but as an input. Second,...

The purpose of this paper is to analyze the efficiency of the 26 Swiss cantons over the period 2000 to 2004 applying Data Envelopment Analysis (DEA). A Total Public Sector Performance (TPSP) indicator for eight local government activities (administration, public safety, education, culture and...

This study uses Markowitz mean-variance portfolio theory with forecasted data for the years 2005 to 2035 to determine efficient electricity generating technology mixes for Switzerland. The SURE procedure has been applied to filter out the systematic components of the covariance matrix. Results...