@inproceedings{BleyD'AndreagiovanniKarch, author = {Bley, Andreas and D'Andreagiovanni, Fabio and Karch, Daniel}, title = {Scheduling technology migration in WDM Networks}, series = {Photonic Networks, 14. 2013 ITG Symposium. Proceedings}, booktitle = {Photonic Networks, 14. 2013 ITG Symposium. Proceedings}, pages = {1 -- 5}, language = {en} } @inproceedings{BleyD'AndreagiovanniKarch, author = {Bley, Andreas and D'Andreagiovanni, Fabio and Karch, Daniel}, title = {WDM Fiber Replacement Scheduling}, series = {Proceedings of INOC 2013}, volume = {41}, booktitle = {Proceedings of INOC 2013}, doi = {10.1016/j.endm.2013.05.092}, pages = {189 -- 196}, language = {en} } @inproceedings{MatuschkeBleyMueller, author = {Matuschke, Jannik and Bley, Andreas and M{\"u}ller, Benjamin}, title = {Approximation Algorithms for Facility Location with Capacitated and Length-Bounded Tree Connections}, volume = {Algorithms -- ESA 2013}, editor = {Bodlaender, Hans L. and Italiano, Giuseppe F.}, publisher = {Springer}, doi = {10.1007/978-3-642-40450-4_60}, pages = {707 -- 718}, abstract = {We consider a generalization of the uncapacitated facility location problem that occurs in planning of optical access networks in telecommunications. Clients are connected to open facilities via depth-bounded trees. The total demand of clients served by a tree must not exceed a given tree capacity. We investigate a framework for combining facility location algorithms with a tree-based clustering approach and derive approximation algorithms for several variants of the problem, using techniques for approximating shallow-light Steiner trees via layer graphs, simultaneous approximation of shortest paths and minimum spanning trees, and greedy coverings.}, language = {en} } @inproceedings{BleyGleixnerKochetal.2012, author = {Bley, Andreas and Gleixner, Ambros and Koch, Thorsten and Vigerske, Stefan}, title = {Comparing MIQCP Solvers to a Specialised Algorithm for Mine Production Scheduling}, series = {Modeling, Simulation and Optimization of Complex Processes. Proceedings of the Fourth International Conference on High Performance Scientific Computing, March 2-6, 2009, Hanoi, Vietnam}, booktitle = {Modeling, Simulation and Optimization of Complex Processes. Proceedings of the Fourth International Conference on High Performance Scientific Computing, March 2-6, 2009, Hanoi, Vietnam}, doi = {10.1007/978-3-642-25707-0_3}, pages = {25 -- 39}, year = {2012}, abstract = {In this paper we investigate the performance of several out-of-the box solvers for mixed-integer quadratically constrained programmes (MIQCPs) on an open pit mine production scheduling problem with mixing constraints. We compare the solvers BARON, Couenne, SBB, and SCIP to a problem-specific algorithm on two different MIQCP formulations. The computational results presented show that general-purpose solvers with no particular knowledge of problem structure are able to nearly match the performance of a hand-crafted algorithm.}, language = {en} } @inproceedings{Bley, author = {Bley, Andreas}, title = {On the Hardness of Finding Small Shortest Path Routing Conflicts}, series = {Proceedings of 4th International Network Optimization Conference (INOC2009)}, booktitle = {Proceedings of 4th International Network Optimization Conference (INOC2009)}, abstract = {Nowadays most data networks use shortest path protocols such as OSPF or IS-IS to route traffic. Given administrative routing lengths for the links of a network, all data packets are sent along shortest paths with respect to these lengths from their source to their destination. One of the most fundamental problems in planning shortest path networks is to decide whether a given set of routing paths forms a valid routing and, if this is not the case, to find a small subset of the given paths that cannot be shortest paths simultaneously for any routing lengths. In this paper we show that it is NP-hard to approximate the size of the smallest shortest path conflict by a factor less than 7/6.}, language = {en} } @inproceedings{BleyMenneKlaehneetal.2008, author = {Bley, Andreas and Menne, Ulrich and Kl{\"a}hne, Roman and Raack, Christian and Wess{\"a}ly, Roland}, title = {Multi-layer network design - A model-based optimization approach}, series = {Proceedings of the PGTS 2008, Berlin, Germany}, booktitle = {Proceedings of the PGTS 2008, Berlin, Germany}, publisher = {Polish-German Teletraffic Symposium}, address = {Berlin, Germany}, pages = {107 -- 116}, year = {2008}, language = {en} } @inproceedings{BleyKoch2008, author = {Bley, Andreas and Koch, Thorsten}, title = {Integer programming approaches to access and backbone IP-network planning}, series = {Modeling, Simulation and Optimization of Complex Processes, Proceedings of the 3rd International Conference on High Performance Scientific Computing, March 6-10, Hanoi, Vietnam}, booktitle = {Modeling, Simulation and Optimization of Complex Processes, Proceedings of the 3rd International Conference on High Performance Scientific Computing, March 6-10, Hanoi, Vietnam}, publisher = {Springer}, pages = {87 -- 110}, year = {2008}, language = {en} } @inproceedings{BleyKochWessaely2004, author = {Bley, Andreas and Koch, Thorsten and Wess{\"a}ly, Roland}, title = {Large-Scale hierarchical networks: How to compute an optimal architecture?}, series = {Networks 2004}, booktitle = {Networks 2004}, editor = {Kaindl, H.}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {3-8007-2840-0}, pages = {429 -- 434}, year = {2004}, language = {en} } @inproceedings{BleyGroetschelWessaely2000, author = {Bley, Andreas and Gr{\"o}tschel, Martin and Wess{\"a}ly, Roland}, title = {Design of broadband virtual private networks: Model and Heuristics for the B-WiN}, series = {Robust communication networks: Interconnection and survivability. DIMACS workshop, Princeton, NJ, USA, 1998 at Rutgers University}, volume = {53}, booktitle = {Robust communication networks: Interconnection and survivability. DIMACS workshop, Princeton, NJ, USA, 1998 at Rutgers University}, editor = {Dean, Nathaniel and Hsu, D. and Ravi, R.}, publisher = {American Mathematical Society}, address = {Providence, RI}, pages = {1 -- 16}, year = {2000}, language = {en} }