In this paper, we study an important class of structured matrices: ”Hierarchically Semi-Separable (HSS)” matrices, for which an efficient hierarchical state based representation called Hierarchically Semi-Separable (HSS) representation can be used to utilize the data sparsity of the HSS matrices. A novel algorithm with O(n) complexity is proposed to construct suboptimal HSS representations from...

A solution method for solving Markov chains for a class of stochastic process algebra terms is presented. The solution technique is based on a reformulation of the underlying continuous-time Markov chain (CTMC) in terms of semi-Markov processes. For the reformulation only local information about the processes running in parallel is needed, and it is therefore never necessary to generate the com...

A numerical method for the least squares solution of certain large sparse singular Lyapunov equations is presented. It is shown that the solution can be obtained as the sum of three parts, each of which is a solution of an easier problem and which can be computed with a low rank approximation. Numerical tests illustrate the effectiveness of the proposed method.

To address the need for published data, considerable effort has gone into formalizing the process of data publication. From funding agencies to publishers, data publication has rapidly become a requirement. Digital Object Identifiers (DOI) and data citations have enhanced the integration and availability of data. The challenge facing data publishers now is to deal with the increased number of p...

Based on F-logic, we specify an advanced data model with object-oriented and logic-oriented features that substantially extend the relational approach. For this model we exhibit and study the counterpart to the well-known decomposition of a relation scheme according to a nontrivial nonkey functional dependency. For decomposing a class of a database schema the transformation of pivoting is used....

Real solution classification of parametric polynomial systems is a crucial problem in real quantifier elimination which interests Volker Weispfenning and others. In this paper, we present a stepwise refinement algorithm for real solution classifications of a class of parametric systems consisting of polynomial equations, inequalities and inequations. For an input system, the algorithm outputs t...