Panos Giannopoulos
Free University of Berlin
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Publication
Featured researches published by Panos Giannopoulos.
The Computer Journal | 2008
Panos Giannopoulos; Christian Knauer; Sue Whitesides
This paper surveys parameterized complexity results for hard geometric algorithmic problems. It includes fixed-parameter tractable problems in graph drawing, geometric graphs, geometric covering and several other areas, together with an overview of the algorithmic techniques used. Fixed-parameter intractability results are surveyed as well. Finally, we give some directions for future research.
symposium on computational geometry | 2005
Mohammad Farshi; Panos Giannopoulos; Joachim Gudmundsson
Given a Euclidean graph G in Rd with n vertices and m edges we consider the problem of adding a shortcut such that the stretch factor of the resulting graph is minimized. Currently, the fastest algorithm for computing the stretch factor of a Euclidean graph runs in O(mn+n2 log n) time, resulting in a trivial O(mn3+n4 log n) time algorithm for computing the optimal shortcut. First, we show that a simple modification yields the optimal solution in O(n4) time using O(n2) space. To reduce the running times we consider several approximation algorithms. Our main result is a (2+ε)-approximation algorithm with running time O(nm+n2(log n+1/ε3d)) using O(n2) space.
SIAM Journal on Computing | 2008
Mohammad Farshi; Panos Giannopoulos; Joachim Gudmundsson
Given a Euclidean graph
Journal of Complexity | 2012
Panos Giannopoulos; Christian Knauer; Magnus Wahlström; Daniel Werner
G
International Journal of Computational Geometry and Applications | 2010
Panos Giannopoulos; Rolf Klein; Christian Knauer; Martin Kutz; Dániel Marx
in
IWPEC'06 Proceedings of the Second international conference on Parameterized and Exact Computation | 2006
Sergio Cabello; Panos Giannopoulos; Christian Knauer
\mathbb{R}^d
european symposium on algorithms | 2005
Sergio Cabello; Panos Giannopoulos; Christian Knauer; Günter Rote
with
scandinavian workshop on algorithm theory | 2004
Mark de Berg; Sergio Cabello; Panos Giannopoulos; Christian Knauer; René van Oostrum; Remco C. Veltkamp
n
Algorithmica | 2016
Sergio Cabello; Panos Giannopoulos
vertices and
arXiv: Computational Geometry | 2009
Panos Giannopoulos; Christian Knauer; Günter Rote
m