One approach to intra-operative registration in computerassisted medical interventions involves matching intra-operatively acquired organ surfaces with pre-operatively generated high resolution surfaces. The matching is based on so-called curvature descriptors assigned to the vertices of the two meshes. Therefore, high compliance of the input meshes with respect to curvature properties is essen...

Data conflation is a major issue in GIS: different geospatial data sets covering overlapping regions, possibly obtained from different sources and using different acquisition techniques, need to be combined into one single consistent data set before the data can be analyzed. The most common occurrence for hydrological applications is conflation of a digital elevation model and rivers. We assume...

I I of Partial A general survey of grid generation is presented with a concern for understanding why grids are necessary, how they are applied, and how they are generated. After an examination of the need for such meshes, the overall applications setting is established with a categorization of the various connectivity patterns. This is split LvetWee~; structured grids and unstructured meshes. A...

Recently, Courbet and Croisille [Math. Model. Numer. Anal., 32, 631–649, 1998] introduced the FV box-scheme for the 2D Poisson problem in the case of triangular meshes. Generalization to higher degree box-schemes has been published by Croisille and Greff [Numer. Methods Partial Differential Equations, 18, 355–373, 2002]. These box-schemes are based on the idea of the finite volume method in tha...

This paper discusses Lyapunov stability of the trivial solution of linear di erentialalgebraic equations. As a criterion for the asymptotic stability we propose a numerical parameter (A;B) characterizing the property of a regular matrix pencil A B to have all nite eigenvalues in the open left half-plane. Numerical aspects for computing this parameter are discussed.

This paper addresses the issue of constructing non-oscillatory, higher than second order, fluctuation splitting methods on unstructured triangular meshes. It highlights the reasons why existing approaches fail and proposes a procedure which can be applied to any high order fluctuation splitting scheme to impose positivity on it. Its success is demonstrated through application to a series of lin...

In this paper a new method for the combination of 2D GIS vector data and 2.5D DTM represented by triangulated irregular networks (TIN) to derive integrated triangular 2.5D object-based landscape models (also known as 2.5D-GIS-TIN) is presented. The algorithm takes into account special geometric constellations and fully exploits existing topologies of both input data sets, it “sews the 2D data i...

We present the TreeScape system which, unlike any other system known to the authors, enables the reuse of pre-computed aggregate query results involving the kinds of irregular dimension hierarchies that occur frequently in practice. The system establishes a foundation for obtaining high-performance query processing while precomputing only few aggregates. It is demonstrated how this reuse of agg...