this text carries out some ideas about exact and p− exact sequences of transformationsemigroups. some theorems like the short five lemma (lemma 1.3 and lemma 2.3) are valid here as inexact sequences of r − modules.

The Weapon Target Assignment (WTA) problem is a fundamental problem arising in defense-related applications of operations research. This problem consists of optimally assigning n weapons to m targets so that the total expected survival value of the targets after all the engagements is minimum. The WTA problem can be formulated as a nonlinear integer programming problem and is known to be NP-com...

In the last few years solid state physics has increasingly benefited from scientific computing and the significance of numerical techniques is likely to keep on growing quickly in this field. Because of the high complexity of solids, which are made of a huge number of interacting electrons and nuclei, a full understanding of their properties cannot be developed using analytical methods only. Nu...

This paper describes two approaches to the problem of determining exact optimal storage capacity for Web caches based on expected workload and the monetary costs of memory and bandwidth. The first approach considers memory/bandwidth tradeoffs in an idealized model. It assumes that workload consists of independent references drawn from a known distribution (e.g., Zipf) and caches employ a “Perfe...

We present here numerical and combinatorial methods that permit the use of exact arithmetic in the construction of unions and intersection of polygonal regions. An argument is given that, even in an exact arithmetic system , rounding of coordinates is necessary. We also argue that it is natural and useful to round to a nonuniform grid, and we give methods for calculating the nearest grid point....

In this thesis, I present several different methods for solving the Car Sequencing Problem. The process of scheduling vehicles along a production line has to take several constraints into account which are defined by the body shop, the paint shop and the assembly shop. I attached importance especially to the paint shop constraints, because no violations are allowed here. Beside the enhancement ...

The motif discovery problem consists of uncovering exceptional patterns (called motifs) in sets of sequences. It arises in molecular biology when searching for yet unknown functional sites in DNA sequences. In this thesis, we develop a motif discovery algorithm that (1) is exact, that means it returns a motif with optimal score, (2) can use the statistical significance with respect to complex b...

In this thesis we explore recent methods for computing the Newton polytope of the implicit equation and study their applicability to the representation change from the parametric form to implicit. Computing a (super)set of the monomials appearing in the implicit equation allows us to determine the interpolation space. Following this phase we implement interpolation by exact or numeric linear al...