Extended abstract In this paper we present a new non-coherent sequence detection algorithm for quadrature amplitude modulations (QAM) transmitted over additive white Gaussian noise (AWGN) channels. Our detection scheme is non-coherent in that it does not need any explicit carrier phase reference. Under the assumption of a constant channel phase model, it may easily be shown that the sampled out...

We describe a two phase algorithm for MAX{SAT and weighted MAX{ SAT problems. In the rst phase, we use the GSAT heuristic to nd a good solution to the problem. In the second phase, we use an enumera-tion procedure based on the Davis{Putnam{Loveland algorithm, to nd a provably optimal solution. The rst heuristic stage improves the performance of the algorithm by obtaining an upper bound on the m...

Recently a characterization of the Lovász theta number based on convex quadratic programming was established. As a consequence of this formulation, we introduce a new upper bound on the stability number of a graph which slightly improves the theta number. Like this number, the new bound can be characterized as the minimum of a function whose values are the optimum values of convex quadratic pro...

Motivated by a strongly growing interest in anonymizing social network data, we investigate the NP-hard Degree Anonymization problem: given an undirected graph, the task is to add a minimum number of edges such that the graph becomes k-anonymous. That is, for each vertex there have to be at least k − 1 other vertices of exactly the same degree. The model of degree anonymization has been introdu...

The use of the stationary phase principle is often advocated for evaluating the spectrum of a chirp. This issue is considered here in detail, especially with respect to the quantitative control of the corresponding approximation error. A careful analysis leads to the introduction of a refined criterion, which turns out to be much more complicated than the heuristic conditions which are usually ...

We consider the topic of partitioning unstructured finite element meshes by a class of multilevel graph partitioning algorithms. Two issues are studied, where the first issue concerns the coarsening phase in such multilevel graph partitioning algorithms. In particular, we propose a new heuristic for matching the vertices of a graph during the coarsening phase. We compare our heuristic with two ...

We show that the same methodology used to study phase transition behavior in NP-complete problems works with a polynomial problem class, establishing arc consistency in constraint satisfaction problems. A general measure of the constrainedness of an ensemble of problems, used to locate phase transitions in random NP-complete problems, predicts the location of a phase transition in establishing ...

Perimeter search is a bidirectional search algorithm consisting of two phases. In the first phase, a limited regression search computes the perimeter, a region which must necessarily be passed in every solution. In the second phase, a heuristic forward search finds an optimal plan from the initial state to the perimeter. The drawback of perimeter search is the need to compute heuristic estimate...

This paper introduces a shift rostering problem that surprisingly has not been studied in literature: the weekend shift rostering problem. It is motivated by our experience that employees’ shift preferences predominantly focus on the weekends, since many social activities happen during weekends. The Weekend Rostering Problem (WRP) addresses the rostering of weekend shifts, for which we design a...