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Krzysztof Walkowiak
Wrocław University of Technology
211Publications
18H-index
1,702Citations
Publications 212
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Abstract In this paper, we propose an optimization system based on an evolutionary algorithm developed to solve a real-life optimization problem related to the optimization of the computer networks. In particular, we focus on an NP-hard flow allocation problem in computer networks related to network survivability and addressing various constraints specific to computer networks. The constrained problems are usually handled by evolutionary methods by the introduction of the so-called penalty facto...
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#1Piotr LechowiczH-Index: 6
#2Roza GoscienH-Index: 10
Last.Krzysztof WalkowiakH-Index: 18
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This article identifies the unavoidably required upgrade of short-term realizable elastic optical networks (EONs) operating over single-mode fibers toward spectrally-spatially flexible optical networks (SS-FONs), exploiting spatial division multiplexing (SDM) technology in order to cope with the expected mid- and long-term future traffic forecasts. Since a complete EON to SS-FON network migration overnight is unrealistic, this article proposes a gradual greenfield migration strategy employing no...
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We focus on the routing, spatial mode, and spectrum allocation (RSSA) problem–a basic optimization problem in spectrally and spatially flexible optical networks (SS-FON). RSSA is a very challenging problem since it introduces a new dimension, related to the selection of spatial resources, to the already complex ( \mathcal {NP}-hard) routing and spectrum allocation (RSA) problem. To allow solving large RSSA problem instances, in particular, in optical backbone networks with tens of nodes and h...
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#1Paweł KsieniewiczH-Index: 4
#2Michał WoźniakH-Index: 12
Last.Krzysztof WalkowiakH-Index: 18
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Abstract Due to variety of modern real-life tasks, where analyzed data is often not a static set, the data stream mining gained a substantial focus of machine learning community. Main property of such systems is the large amount of data arriving in a sequential manner, which creates an endless stream of objects. Taking into consideration the limited resources as memory and computational power, it is widely accepted that each instance can be processed up once and it is not remembered, making reev...
1 CitationsSource
#1Krzysztof WalkowiakH-Index: 18
#2Roza GoscienH-Index: 10
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Optimization of lightpath provisioning in a spectrally-spatially flexible optical network (SS-FON) is challenging due to many difficult constraints that exist in optical networks and because of limited amounts of various transmission resources (such as spectrum, spatial modes, transceivers, regeneration points). Previously demonstrated approaches usually apply fixed provisioning policies (e.g., heuristics for routing, space and spectrum assignment (RSSA)) and fail to completely address the chara...
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Knowledge about future traffic in a dynamic optical network can be used to improve various performance metrics, including network cost and to reduce complexity of solving network optimization problems. In this paper, we propose a machine learning approach of predicting demands in a dynamic optical network serving Virtual Network Function (VNF) chain traffic. We also present numerical results proving effectiveness of the described methodology and showing comparison of various classifiers. Dataset...
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May 1, 2019 in ICC (International Conference on Communications)
#1Krzysztof Walkowiak (Wrocław University of Technology)H-Index: 18
Last.Miroslaw Klinkowski (UPC: Polytechnic University of Catalonia)H-Index: 21
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We focus on dynamic crosstalk-aware lightpath provisioning in translucent space-division multiplexing (SDM) elastic optical networks, in which spectral super-channels are carried over multi-core fibers (MCFs), distance-adaptive transmission is considered, and back-to-back (B2B) signal regeneration is applied. We aim at establishing lightpaths for connection requests in such a way that the inter-core crosstalk (XT) impairment affecting the quality of lightpaths in the network does not exceed allo...
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Abstract Evolutionary methods are well-known tools used for solving hard computational problems. In this paper, we consider k-Shortest Steiner Trees (kSST) problem appearing in a diverse set of domains, e.g., multicast tree construction in communication networks in general, and optical networks in particular. The kSST is relatively new and has not been widely investigated in the literature. Thus, only a few algorithms have been proposed, each requiring significant resources amount and long execu...
1 CitationsSource
#1Piotr LechowiczH-Index: 6
#2Ruben Rumipamba-Zambrano (UPC: Polytechnic University of Catalonia)H-Index: 4
Last.Krzysztof WalkowiakH-Index: 18
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We study inter-core crosstalk (ICXT) impact on migration planning toward spectrally-spatially flexible optical networks considering 22-core multi-core fiber. Results reveal, 55-70% of links need to be upgraded when ICXT ranges from −68.2 to −43.4 dB/km.1
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#1Krzysztof WalkowiakH-Index: 18
#2Róża GościeńH-Index: 4
Last.Miroslaw KlinkowskiH-Index: 21
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We focus on spectrally-spatially flexible optical networks and analyze benefits of adjusting the number of active spatial modes in network links using various metrics based on data analytics with the goal to maximize the served traffic.1
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