Among the challenges of managing NASA’s information systems is the management (that is, creation, coordination, verification, validation, and enforcement) of many different role-based access control policies and mechanisms. This paper describes an actual data federation use case that demonstrates the inefficiencies created by this challenge and presents an approach to reducing these inefficienc...

The recently proposed Riemannian Trust-Region method can be applied to the problem of computing extreme eigenpairs of a matrix pencil, with strong global convergence and local convergence properties. This paper addresses inherent inefficiencies of an explicit trustregion mechanism. We propose a new algorithm, the Implicit Riemannian Trust-Region method for extreme eigenpair computation, which s...

Standard approaches to the theory of financial markets are based on equilibrium and efficiency. Here we develop an alternative concepts methods developed by biologists, in which wealth invested a strategy is like abundance species. We study toy model market consisting value investors, trend followers noise traders. show that average returns strategies strongly density dependent, i.e. they depen...

Adding self-adaptation as a property to systems aims at improving the efficiency of this system. But there is always the possibility for adaptations going too far, which is very detrimental to the trust of users into a self-adapting system. In this paper, we present a method for testing the efficiency of a self-adapting system, more precisely the potential for inefficiencies after adaptation ha...

In this paper we investigate whether stock market overpricing leads to aggregate (real) inefficiencies. We first investigate a standard dynamic contracting model of investment subject to financing constraints. We show that stock market mispricing will have two robust effects on welfare: on the one hand it will distort investment decisions and lead to inefficiencies. On the other hand it will al...

A common principle of electricity pricing is ensuring that costs and benefits are aligned such economic efficiency optimized. Deviations from this commonplace in residential pricing, especially for distributed generation (DG). Here, subsidizing renewable energy sources can sometimes precede considerations, causing a divergence between the real value household’s DG credits household receives. He...