Research Areas

Combinatorial Optimization and Mixed Integer Programming

• Telecommunication Network Design
• network flow, capacity assignment, survivability
• integrated planning of multi-layer networks
• polyhedral combinatorics


• Mixed Integer Programming
• strong valid inequalities, separation, cutting plane techniques
• mixed integer rounding

Current Projects

Matheon Project B3 "Integrated planning of multi-layer networks"
IT2Green--DESI Durchgängige energiesensible IKT
ZIB-IBM(ILOG) Cooperation
Solving Constraint Integer Programs	SCIP
Past Projects
Efficient Integrated Backbone
MLTN - Multilayer Transport Networks

Publications

[2012] [2011] [2010] [2009] [2008] [2007] [2005] 

2012

Authors	Ulrich Menne, Christian Raack, Roland Wessäly, Daniel Kharitonov
Title	Optimal Degree of Optical Circuit Switching in IP-over-WDM Networks
Booktitle	Proceedings of the 16th conference on Optical network design and modeling, ONDM 2012
Published	to appear, 2012
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2011

Authors	Filip Idzikowski, Sebastian Orlowski, Christian Raack, Hagen Woesner, Adam Wolisz
Title	Dynamic routing at different layers in IP-over-WDM networks - Maximizing energy savings
Journal	Optical Switching and Networking, Special Issue on Green Communications, 8:3 (2011) 181-200
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Authors	Arie M. C. A. Koster, Manuel Kutschka, Christian Raack
Title	Robust Network Design: Formulations, Valid Inequalities, and Computations
Number	ZIB Report 11-34, 2011
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Authors	Sanjeeb Dash, Oktay Günlük, Christian Raack
Title	A note on the MIR closure and basic relaxations of polyhedra
Journal	Optimization Research Letters, 39:3 (2011) 198-199
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Authors	Christian Raack, Arie M. C. A. Koster, Sebastian Orlowski, Roland Wessäly
Title	On cut-based inequalities for capacitated network design polyhedra
Journal	Networks, 57:2 (2011) 141-156
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2010

Authors	Tobias Achterberg, Christian Raack
Title	The MCF-Separator - Detecting and Exploiting Multi-Commodity Flows in MIPs
Journal	Mathematical Programming C, 2 (2010) 125-165
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2009

Authors	Arie M. C. A. Koster, Sebastian Orlowski, Christian Raack, Georg Baier, Thomas Engel, Pietro Belotti
Title	Branch-and-cut techniques for solving realistic two-layer network design problems
Booktitle	Graphs and Algorithms in Communication Networks
Published	Springer Berlin Heidelberg, 2009, 95-118
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Authors	Arie M. C. A. Koster, Christian Raack
Title	A packing integer program arising in two-layer network design
Booktitle	Proceedings of the INOC 2009, Pisa, Italy
Published	International Network Optimization Conference, 2009
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2008

Authors	Andreas Bley, Ullrich Menne, Roman Klähne, Christian Raack, Roland Wessäly
Title	Multi-layer network design - A model-based optimization approach
Booktitle	Proceedings of the PGTS 2008, Berlin, Germany
Published	Polish-German Teletraffic Symposium, 2008, 107-116
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Authors	Arie M. C. A. Koster, Sebastian Orlowski, Christian Raack, Georg Baier, Thomas Engel
Title	Single-layer Cuts for Multi-Layer Network Design Problems
Booktitle	Telecommunications Modeling Policy and Technology, also ZIB Report ZR-07-21
Published	Springer, 2008, 1-23
Note	Selected proceedings of the 9th INFORMS Telecommunications Conference
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2007

Authors	Christian Raack, Arie M. C. A. Koster, Sebastian Orlowski, Roland Wessäly
Title	Capacitated network design using general flow-cutset inequalities
Booktitle	Proceedings of the INOC 2007, Spa, Belgium, also ZIB Report ZR-07-14
Published	International Network Optimization Conference, 2007
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Authors	Sebastian Orlowski, Arie M. C. A. Koster, Christian Raack, Roland Wessäly
Title	Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics
Booktitle	Proceedings of the INOC 2007, Spa, Belgium, also ZIB Report ZR-06-47
Published	International Network Optimization Conference, 2007
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Authors	Christian Raack, Arie M. C. A. Koster, Roland Wessäly
Title	On the strength of cut-based inequalities for capacitated network design polyhedra
Number	ZIB Report 07-08, 2007
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2005

Authors	Christian Raack
Title	Employing Mixed-Integer Rounding in Telecommunication Network Design
Year	2005
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Last change 2012-03-19