Given a set of rectangular items of different sizes and a rectangular container, the aim of the bi-dimensional Orthogonal Packing Problem (OPP-2 for short) is to decide whether there exists a non-overlapping packing of the items in this container. The rotation of items is not allowed. In this paper we present a new exact algorithm for solving OPP-2, based upon the characterization of solutions ...

Power grid vulnerability is a major concern of our society, and its protection problem is often formulated as a tri-level defender-attacker-defender model. However, this tri-level problem is computationally challenging. In this paper, we design and implement a Column-and-Constraint Generation algorithm to derive its optimal solutions. Numerical results on an IEEE system show that: (i) the devel...

Current DNA sequencing technologies do not read an entire chromosome from end to end but instead produce sets of short reads, i.e. fragments of the genome. Haplotype assembly is the problem of assigning each read to the correct chromosome in the set of chromosomes in a homologous group, with the aid of the reference sequence. In this paper, we extend an existing exact algorithm for haplotype as...

We consider the problem of augmenting a graph with n vertices embedded in a metric space, by inserting one additional edge in order to minimize the diameter of the resulting graph. We present an exact algorithm for the cases when the input graph is a path that runs in O(n log n) time. We also present an algorithm that computes a (1 + ε)approximation in O(n+1/ε) time for paths in R, where d is a...

In the Intervalizing Colored Graphs problem, one must decide for a given graph G = (V,E) with a proper vertex coloring of G whether G is the subgraph of a properly colored interval graph. For the case that the number of colors k is xed, we give an exact algorithm that uses O∗(2n/log (n)) time for all > 0. We also give an O∗(2n) algorithm for the case that the number of colors k is not xed.

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.

Let G be an unweighted graph on n vertices. We show that an embedding of the shortest path metric of G into the line with minimum distortion can be found in time 5. This is the first algorithm breaking the trivial n!-barrier.

Realization of efficient Universal Logic Modules (ULMs) is a challenging topic in circuit design. The goal is to find a representation that allows to realize as many Boolean functions as possible by permutation of inputs or phase assignment. In this paper an exact algorithm for finding a minimal circuit for a ULM is presented. The approach is parametrisized in several ways, e.g. the user can de...

In this paper we study a variant of the Capacitated Team Orienteering Problem (CTOP), that is the problem where a fleet of vehicles, each with a constraint on the time available, is given to serve profitable customers with the objective of maximizing the collected profit. We study the variant where customers may be only partially served (incomplete service) and, if beneficial, also by more than...

This paper presents an algorithm for comparing large numbers of traces to each other and identifying and presenting groups of traces with similar features. It is applied to forensic analysis in which groups of similar traces are automatically identified and presented so that attribution and other related claims may be asserted, and independently confirmed or refuted. The approach of this paper ...