@article{BetkerKosiankowskiLangeetal.2014, author = {Betker, Andreas and Kosiankowski, Dirk and Lange, Christoph and Pfeuffer, Frank and Raack, Christian and Werner, Axel}, title = {Energy efficiency in extensive IP-over-WDM networks with protection}, journal = {Operations Research Proceedings 2012}, editor = {Helber, Stefan and Breitner, Michael and R{\"o}sch, Daniel and Sch{\"o}n, Cornelia and Graf von der Schulenburg, Johann-Matthias and Sibbertsen, Philipp and Steinbach, Marc and Weber, Stefan and Wolter, Anja}, publisher = {Springer}, doi = {10.1007/978-3-319-00795-3_14}, pages = {93 -- 99}, year = {2014}, language = {en} } @misc{BetkerKosiankowskiLangeetal.2012, author = {Betker, Andreas and Kosiankowski, Dirk and Lange, Christoph and Pfeuffer, Frank and Raack, Christian and Werner, Axel}, title = {Energy efficiency in extensive multilayer core and regional networks with protection}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-17154}, year = {2012}, abstract = {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?}, language = {en} } @misc{DraegertEisenblaetterGamrathetal.2015, author = {Draegert, Andreas and Eisenbl{\"a}tter, Andreas and Gamrath, Inken and Werner, Axel}, title = {Optimal Battery Controlling for Smart Grid Nodes}, issn = {1438-0064}, doi = {10.1007/978-4-431-55420-2_6}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-53550}, year = {2015}, abstract = {Energy storages can be of great value when added to power grids. They introduce the possibility to store and release energy whenever this is favorable. This is particularly relevant, for example, if power supply is volatile (as is the case with renewable energy) and the network is small (so that there are few other nodes that might balance fluctuations in consumption or production). We present models and methods from mathematical optimization for computing an optimized storage schedule for this purpose. We look at alternative optimization objectives, such as smallest possible peak load, low energy costs, or the close approximation of a prescribed load curve. The optimization needs to respect general operational and economic constraints as well as limitations in the use of storage, which are imposed by the chosen storage technology. We therefore introduce alternative approaches for modeling the non-linear properties of energy storages and study their impact on the efficiency of the optimization process. Finally, we present a computational study with batteries as storage devices. We use this to highlight the trade-off between solution quality and computational tractability. A version of the model for the purpose of leveling peaks and instabilities has been implemented into a control system for an office-building smart grid scenario.}, language = {en} } @misc{BetkerGamrathKosiankowskietal.2014, author = {Betker, Andreas and Gamrath, Inken and Kosiankowski, Dirk and Lange, Christoph and Lehmann, Heiko and Pfeuffer, Frank and Simon, Felix and Werner, Axel}, title = {Comprehensive Topology and Traffic Model of a Nation-wide Telecommunication Network}, issn = {1438-0064}, doi = {10.1364/JOCN.6.001038}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-52670}, year = {2014}, abstract = {As a basis for meaningful simulation and optimization efforts with regard to traffic engineering or energy consumption in telecommunication networks, suitable models are indispensable. This concerns not only realistic network topologies, but also models for the geographical distribution and the temporal dynamics of traffic, as well as the assumptions on network components and technology. This paper derives such a model from the practice of a large national carrier. Applying the network and traffic model, we demonstrate its use by presenting various optimization cases related to energy-efficient telecommunication. Here, we focus on load-adaptivity by employing sleep modes to the network hardware, where several constraints on the reconfigurability of the network over time are considered.}, language = {en} } @misc{WernerAurzadaBleyetal.2014, author = {Werner, Axel and Aurzada, Frank and Bley, Andreas and Eisenbl{\"a}tter, Andreas and Geerdes, Hans-Florian and Guillemard, Mijail and Kutyniok, Gitta and Philipp, Friedrich and Raack, Christian and Scheutzow, Michael}, title = {Mathematics for telecommunications}, volume = {1}, journal = {MATHEON - Mathematics for Key Technologies}, editor = {Deuflhard, Peter and Gr{\"o}tschel, Martin and H{\"o}mberg, Dietmar and Horst, Ulrich and Kramer, J{\"u}rg and Mehrmann, Volker and Polthier, Konrad and Schmidt, Frank and Sch{\"u}tte, Christof and Skutella, Martin and Sprekels, J{\"u}rgen}, edition = {EMS Series in Industrial and Applied Mathematics}, publisher = {European Mathematical Society}, doi = {10.4171/137}, pages = {75 -- 89}, year = {2014}, language = {en} } @inproceedings{SchlosserWernerSchlenketal.2014, author = {Schlosser, Michael and Werner, Axel and Schlenk, Ralph and Jungel, Tobias and Lange, Christoph}, title = {Demonstrating energy-efficiency improvements in load-adaptive dynamic multilayer optical networks}, volume = {248}, booktitle = {Tagungsband Photonische Netze}, publisher = {VDE-Verlag}, pages = {42 -- 46}, year = {2014}, abstract = {The discussion about sustainability and climate change as well as the energy cost perspective of network operators gives increasing attention to the energy efficiency of telecommunication networks. A promising way to improve the energy efficiency of such networks is the load-adaptive operation in which the network capacity is adjusted to the actual timevarying traffic transport needs. In this paper the concept of load-adaptive operation in the core network is explained, with the respective underlying optical network and the associated mathematical optimization. Within the DESI project a demonstrator has been realized with a commercially available WDM/OTN system. As results, concrete proven power and energy savings and the projected savings for a nationwide multilayer core network are reported.}, language = {en} } @inproceedings{DraegertEisenblaetterGamrathetal.2015, author = {Draegert, Andreas and Eisenbl{\"a}tter, Andreas and Gamrath, Inken and Werner, Axel}, title = {Optimal battery control for smart grid nodes}, volume = {13}, booktitle = {Optimization in the Real World - Towards Solving Real-World Optimization Problems}, editor = {Fujisawa, Katsuki and Shinano, Yuji and Waki, Hayato}, publisher = {Springer}, doi = {10.1007/978-4-431-55420-2_6}, pages = {97 -- 113}, year = {2015}, abstract = {Energy storages can be of great value when added to power grids. They introduce the possibility to store and release energy whenever this is favorable. This is particularly relevant, for example, if power supply is volatile (as is the case with renewable energy) and the network is small (so that there are few other nodes that might balance fluctuations in consumption or production). We present models and methods from mathematical optimization for computing an optimized storage schedule for this purpose. We look at alternative optimization objectives, such as smallest possible peak load, low energy costs, or the close approximation of a prescribed load curve. The optimization needs to respect general operational and economic constraints as well as limitations in the use of storage, which are imposed by the chosen storage technology. We therefore introduce alternative approaches for modeling the non-linear properties of energy storages and study their impact on the efficiency of the optimization process. Finally, we present a computational study with batteries as storage devices. We use this to highlight the trade-off between solution quality and computational tractability. A version of the model for the purpose of leveling peaks and instabilities has been implemented into a control system for an office-building smart grid scenario.}, language = {en} } @article{BetkerGamrathKosiankowskietal.2014, author = {Betker, Andreas and Gamrath, Inken and Kosiankowski, Dirk and Lange, Christoph and Lehmann, Heiko and Pfeuffer, Frank and Simon, Felix and Werner, Axel}, title = {Comprehensive Topology and Traffic Model of a Nationwide Telecommunication Network}, volume = {6}, journal = {Journal of Optical Communications and Networking}, number = {11}, doi = {10.1364/JOCN.6.001038}, pages = {1038 -- 1047}, year = {2014}, abstract = {As a basis for meaningful simulation and optimization efforts with regard to traffic engineering or energy consumption in telecommunication networks, suitable models are indispensable. This concerns not only realistic network topologies but also models for the geographical distribution and the temporal dynamics of traffic, as well as the assumptions on network components and technology. This paper derives such a model from the practice of a large national carrier. Applying the network and traffic model, we demonstrate its use by presenting various optimization cases related to energy-efficient telecommunication. Here, we focus on load adaptivity by employing sleep modes to the network hardware, where several constraints on the reconfigurability of the network over time are considered.}, language = {en} }