TY - GEN A1 - Betker, Andreas A1 - Kosiankowski, Dirk A1 - Lange, Christoph A1 - Pfeuffer, Frank A1 - Raack, Christian A1 - Werner, Axel T1 - Energy efficiency in extensive multilayer core and regional networks with protection N2 - Energy-efficient operation of large telecommunication networks is an important issue today and in the near future. Given that the energy consumption rises with the ever increasing demand for capacity and network speed, there is a growing interest in strategies for a sustainable network management. It is a well-known fact that traffic demands vary significantly over time, most notably in day/night- and in weekly cycles. This provides the main potential for energy-saving strategies. We study the question of how much power is necessary to operate a network with state-of-the-art hardware during peak or low-traffic times. The study respects realistic side constraints, such as protection requirements and routing schemes, and takes the special structure of an extensive nation-wide optical network, including backbone and regional sections, into account. We formulate mixed integer programming models for the corresponding optimization problems using predictions for traffic matrices, as well as state-of-the-art hardware and power models. We address questions as the following: How much energy is spent in the core and in metro regions of the network and how big are the savings in low-demand scenarios if we always assume the system power-minimum in these situations? What is the influence of different hardware on the overall energy consumption? How much do different routing schemes or protection scenarios restrict potential energy savings? T3 - ZIB-Report - 12-45 KW - telecommunications KW - network design KW - routing KW - energy efficiency Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-17154 SN - 1438-0064 ER - TY - GEN A1 - Wessäly, Roland A1 - Werner, Axel A1 - Eckel, Klaus A1 - Seibel, Julia A1 - Orlowski, Sebastian A1 - Louchet, Hadrien A1 - Patzak, Erwin A1 - Bentz, Winfried T1 - Schätze heben bei der Planung von FTTx-Netzen: optimierte Nutzung von existierenden Leerrohren - eine Praxisstudie N2 - Das vom BMBF geförderte Projekt FTTX-PLAN entwickelt mathematische Modelle und Optimierungsverfahren, um automatisiert kostenoptimierte FTTx-Netze berechnen zu können. Wir zeigen anhand einer Praxisstudie in Zusammenarbeit mit der Regensburger R-KOM, wie ein Planer von diesen Verfahren profitieren kann, um die Auswirkungen bestimmter Entscheidungen auf die Netzstruktur und -kosten zu untersuchen. Wir illustrieren dies am Beispiel eines FTTB/FTTH-Vergleichs, der Variation von Kundenanbindungsraten und der gezielten Ausnutzung existierender Leerrohre, um Tiefbau zu vermeiden. T3 - ZIB-Report - 11-47 KW - Praxisstudie KW - Optische Zugangsnetze KW - Optimierung Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-14861 UR - http://www.vde-verlag.de/buecher/453339/breitbandversorgung-in-deutschland-itg-fb-227.html SN - 1438-0064 ER - TY - GEN A1 - Werner, Axel T1 - Kombinatorische Optimierung und die 40-Punkte-Regel N2 - Wieviele Punkte braucht eine Mannschaft in der Fußball-Bundesliga mindestens, um sicher dem Abstieg zu entgehen? Wir benutzen kombinatorische Optimierung, um diese und ähnliche Fragen zu beantworten. T3 - ZIB-Report - 11-48 KW - Kombinatorische Optimierung KW - Sport KW - Bundesliga Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-14871 SN - 1438-0064 ER - TY - GEN A1 - Orlowski, Sebastian A1 - Werner, Axel A1 - Wessäly, Roland T1 - Estimating trenching costs in FTTx network planning N2 - In this paper we assess to which extent trenching costs of an FTTx network are unavoidable, even if technical side constraints are neglected. For that purpose we present an extended Steiner tree model. Using a variety of realistic problem instances we demonstrate that the total trenching cost can only be reduced by about 5 percent in realistic scenarios. This work has been funded by BMBF (German Federal Ministry of Education and Research) within the program "KMU-innovativ". T3 - ZIB-Report - 11-49 KW - Optical access networks KW - Optimization KW - Steiner trees Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-14884 SN - 1438-0064 ER - TY - CHAP A1 - Bentz, Winfried A1 - Eckel, Klaus A1 - Louchet, Hadrien A1 - Orlowski, Sebastian A1 - Patzak, Erwin A1 - Seibel, Julia A1 - Werner, Axel A1 - Wessäly, Roland T1 - Schätze heben bei der Planung von FTTx-Netzen T2 - Breitbandversorgung in Deutschland Y1 - 2011 VL - 227 PB - VDE-Verlag ER - TY - JOUR A1 - Werner, Axel A1 - Wotzlaw, Ronald T1 - On linkages in polytope graphs JF - Adv. Geom. Y1 - 2011 U6 - https://doi.org/10.1515/ADVGEOM.2011.015 VL - 11 IS - 3 SP - 411 EP - 427 ER - TY - JOUR A1 - Werner, Axel T1 - Kombinatorische Optimierung und die 40-Punkte-Regel JF - Mitteilungen der DMV Y1 - 2011 VL - 19 SP - 153 EP - 157 ER - TY - CHAP A1 - Orlowski, Sebastian A1 - Werner, Axel A1 - Wessäly, Roland ED - Klatte, Diethart ED - Lüthi, Hans-Jakob ED - Schmedders, Karl T1 - Estimating trenching costs in FTTx network planning T2 - Operations Research Proceedings 2011 Y1 - 2012 SP - 89 EP - 94 PB - Springer Verlag ER - TY - GEN A1 - Werner, Axel T1 - Smallest non-trivial 2s2s-polytope Y1 - 2005 UR - http://www.eg-models.de/2005.12.001 PB - EG Model, online ER - TY - JOUR A1 - Paffenholz, Andreas A1 - Werner, Axel T1 - Constructions for 4-polytopes and the cone of flag vectors. JF - Contemporary Mathematics Y1 - 2006 VL - 423 SP - 283 EP - 303 PB - Algebraic and geometric combinatorics. Euroconference in mathematics, algebraic and geometric combinatorics, Anogia, Crete, Greece, August 20–26, 2005. Providence, RI: American Mathematical Society (AMS) ER -