TY - CHAP A1 - Bley, Andreas A1 - D'Andreagiovanni, Fabio A1 - Karch, Daniel T1 - Scheduling technology migration in WDM Networks T2 - Photonic Networks, 14. 2013 ITG Symposium. Proceedings Y1 - 2013 SP - 1 EP - 5 ER - TY - CHAP A1 - Bley, Andreas A1 - D'Andreagiovanni, Fabio A1 - Karch, Daniel T1 - WDM Fiber Replacement Scheduling T2 - Proceedings of INOC 2013 Y1 - 2013 U6 - https://doi.org/10.1016/j.endm.2013.05.092 VL - 41 SP - 189 EP - 196 ER - TY - CHAP A1 - Matuschke, Jannik A1 - Bley, Andreas A1 - Müller, Benjamin ED - Bodlaender, Hans L. ED - Italiano, Giuseppe F. T1 - Approximation Algorithms for Facility Location with Capacitated and Length-Bounded Tree Connections N2 - 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. Y1 - 2013 U6 - https://doi.org/10.1007/978-3-642-40450-4_60 VL - Algorithms -- ESA 2013 SP - 707 EP - 718 PB - Springer ER - TY - CHAP A1 - Bley, Andreas A1 - Gleixner, Ambros A1 - Koch, Thorsten A1 - Vigerske, Stefan T1 - Comparing MIQCP Solvers to a Specialised Algorithm for Mine Production Scheduling T2 - Modeling, Simulation and Optimization of Complex Processes. Proceedings of the Fourth International Conference on High Performance Scientific Computing, March 2-6, 2009, Hanoi, Vietnam N2 - 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. Y1 - 2012 U6 - https://doi.org/10.1007/978-3-642-25707-0_3 SP - 25 EP - 39 ER - TY - CHAP A1 - Bley, Andreas T1 - On the Hardness of Finding Small Shortest Path Routing Conflicts T2 - Proceedings of 4th International Network Optimization Conference (INOC2009) N2 - 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. Y1 - 2009 ER - TY - CHAP A1 - Bley, Andreas A1 - Menne, Ulrich A1 - Klähne, Roman A1 - Raack, Christian A1 - Wessäly, Roland T1 - Multi-layer network design – A model-based optimization approach T2 - Proceedings of the PGTS 2008, Berlin, Germany Y1 - 2008 SP - 107 EP - 116 PB - Polish-German Teletraffic Symposium CY - Berlin, Germany ER - TY - CHAP A1 - Bley, Andreas A1 - Koch, Thorsten T1 - Integer programming approaches to access and backbone IP-network planning T2 - Modeling, Simulation and Optimization of Complex Processes, Proceedings of the 3rd International Conference on High Performance Scientific Computing, March 6-10, Hanoi, Vietnam Y1 - 2008 UR - http://opus.kobv.de/zib/volltexte/2002/709/ SP - 87 EP - 110 PB - Springer ER - TY - CHAP A1 - Bley, Andreas A1 - Koch, Thorsten A1 - Wessäly, Roland ED - Kaindl, H. T1 - Large-Scale hierarchical networks: How to compute an optimal architecture? T2 - Networks 2004 Y1 - 2004 SN - 3-8007-2840-0 SP - 429 EP - 434 PB - VDE Verlag CY - Berlin ER - TY - CHAP A1 - Bley, Andreas A1 - Grötschel, Martin A1 - Wessäly, Roland ED - Dean, Nathaniel ED - Hsu, D. ED - Ravi, R. T1 - Design of broadband virtual private networks: Model and Heuristics for the B–WiN T2 - Robust communication networks: Interconnection and survivability. DIMACS workshop, Princeton, NJ, USA, 1998 at Rutgers University Y1 - 2000 VL - 53 SP - 1 EP - 16 PB - American Mathematical Society CY - Providence, RI ER -