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  <doc>
    <id>941</id>
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    <language>eng</language>
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    <type>reportzib</type>
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    <completedDate>2006-11-16</completedDate>
    <publishedDate>2006-11-16</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics</title>
    <abstract language="eng">This paper deals with MIP-based primal heuristics to be used within a branch-and-cut approach for solving multi-layer telecommunication network design problems. Based on a mixed-integer programming formulation for two network layers, we present three heuristics for solving important subproblems, two of which solve a sub-MIP. On multi-layer planning instances with many parallel logical links, we show the effectiveness of our heuristics in finding good solutions early in the branch-and-cut search tree.</abstract>
    <identifier type="serial">06-47</identifier>
    <identifier type="opus3-id">941</identifier>
    <identifier type="urn">urn:nbn:de:0297-zib-9412</identifier>
    <enrichment key="SourceTitle">Appeared in: Proceedings International Network Optimization Conference, INOC 2007, Spa, Belgium.</enrichment>
    <author>Sebastian Orlowski</author>
    <author>Arie M.C.A. Koster</author>
    <author>Christian Raack</author>
    <author>Roland Wessäly</author>
    <series>
      <title>ZIB-Report</title>
      <number>06-47</number>
    </series>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>multi-layer network design</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>integer programming</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>branch-and-cut</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>heuristics</value>
    </subject>
    <collection role="ddc" number="000">Informatik, Informationswissenschaft, allgemeine Werke</collection>
    <collection role="msc" number="90B18">Communication networks [See also 68M10, 94A05]</collection>
    <collection role="msc" number="90C57">Polyhedral combinatorics, branch-and-bound, branch-and-cut</collection>
    <collection role="msc" number="90C59">Approximation methods and heuristics</collection>
    <collection role="institutes" number="">ZIB Allgemein</collection>
    <collection role="projects" number="BMBF-Eibone">BMBF-Eibone</collection>
    <collection role="projects" number="MATHEON-B3">MATHEON-B3</collection>
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    <file>https://opus4.kobv.de/opus4-zib/files/941/ZR-06-47.pdf</file>
    <file>https://opus4.kobv.de/opus4-zib/files/941/ZR-06-47.ps</file>
  </doc>
  <doc>
    <id>3295</id>
    <completedYear>2011</completedYear>
    <publishedYear>2011</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>141</pageFirst>
    <pageLast>156</pageLast>
    <pageNumber/>
    <edition/>
    <issue>2</issue>
    <volume>57</volume>
    <type>article</type>
    <publisherName/>
    <publisherPlace/>
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    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
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    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">On cut-based inequalities for capacitated network design polyhedra</title>
    <parentTitle language="eng">Networks</parentTitle>
    <identifier type="url">http://onlinelibrary.wiley.com/doi/10.1002/net.20395/abstract</identifier>
    <enrichment key="PeerReviewed">yes</enrichment>
    <author>Christian Raack</author>
    <author>Arie M.C.A. Koster</author>
    <author>Sebastian Orlowski</author>
    <author>Roland Wessäly</author>
    <collection role="institutes" number="optimization">Mathematical Optimization</collection>
    <collection role="institutes" number="aopt">Applied Optimization</collection>
  </doc>
  <doc>
    <id>951</id>
    <completedYear/>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
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    <type>reportzib</type>
    <publisherName/>
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    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2007-04-17</completedDate>
    <publishedDate>2007-04-17</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">On the strength of cut-based inequalities for capacitated network design polyhedra</title>
    <abstract language="eng">In this paper we study capacitated network design problems, differentiating directed, bidirected and undirected link capacity models. We complement existing polyhedral results for the three variants by new classes of facet-defining valid inequalities and unified lifting results. For this, we study the restriction of the problems to a cut of the network. First, we show that facets of the resulting cutset polyhedra translate into facets of the original network design polyhedra if the two subgraphs defined by the network cut are (strongly) connected. Second, we provide an analysis of the facial structure of cutset polyhedra, elaborating the differences caused by the three different types of capacity constraints. We present flow-cutset inequalities for all three models and show under which conditions these are facet-defining. We also state a new class of facets for the bidirected and undirected case and it is shown how to handle multiple capacity modules by Mixed Integer Rounding (MIR).</abstract>
    <identifier type="serial">07-08</identifier>
    <identifier type="opus3-id">951</identifier>
    <identifier type="urn">urn:nbn:de:0297-zib-9512</identifier>
    <author>Christian Raack</author>
    <author>Arie M.C.A. Koster</author>
    <author>Roland Wessäly</author>
    <series>
      <title>ZIB-Report</title>
      <number>07-08</number>
    </series>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>cutset-polyhedra</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>flow-cutset inequalities</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>network design</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mixed integer programming</value>
    </subject>
    <collection role="ddc" number="000">Informatik, Informationswissenschaft, allgemeine Werke</collection>
    <collection role="msc" number="90B18">Communication networks [See also 68M10, 94A05]</collection>
    <collection role="msc" number="90C11">Mixed integer programming</collection>
    <collection role="msc" number="90C35">Programming involving graphs or networks [See also 90C27]</collection>
    <collection role="msc" number="90C57">Polyhedral combinatorics, branch-and-bound, branch-and-cut</collection>
    <collection role="institutes" number="">ZIB Allgemein</collection>
    <collection role="projects" number="BMBF-Eibone">BMBF-Eibone</collection>
    <collection role="projects" number="MATHEON-B3">MATHEON-B3</collection>
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    <file>https://opus4.kobv.de/opus4-zib/files/951/ZR-07-08.pdf</file>
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    <file>https://opus4.kobv.de/opus4-zib/files/951/ZR-07-08.ps</file>
  </doc>
  <doc>
    <id>957</id>
    <completedYear/>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
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    <completedDate>2007-06-07</completedDate>
    <publishedDate>2007-06-07</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Capacitated network design using general flow-cutset inequalities</title>
    <abstract language="eng">This paper deals with directed, bidirected, and undirected capacitated network design problems. Using mixed integer rounding (MIR), we generalize flow-cutset inequalities to these three link types and to an arbitrary modular link capacity structure, and propose a generic separation algorithm. In an extensive computational study on 54 instances from the Survivable Network Design Library (SNDlib), we show that the performance of cplex can significantly be enhanced by this class of cutting planes. The computations reveal the particular importance of the subclass of cutset-inequalities.</abstract>
    <identifier type="serial">07-14</identifier>
    <identifier type="opus3-id">957</identifier>
    <identifier type="urn">urn:nbn:de:0297-zib-9576</identifier>
    <author>Christian Raack</author>
    <author>Arie M.C.A. Koster</author>
    <author>Sebastian Orlowski</author>
    <author>Roland Wessäly</author>
    <series>
      <title>ZIB-Report</title>
      <number>07-14</number>
    </series>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>general flow-cutset inequalities</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>capacitated network design</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mixed integer rounding</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>SNDlib</value>
    </subject>
    <collection role="ddc" number="000">Informatik, Informationswissenschaft, allgemeine Werke</collection>
    <collection role="msc" number="90B18">Communication networks [See also 68M10, 94A05]</collection>
    <collection role="msc" number="90C11">Mixed integer programming</collection>
    <collection role="msc" number="90C35">Programming involving graphs or networks [See also 90C27]</collection>
    <collection role="msc" number="90C57">Polyhedral combinatorics, branch-and-bound, branch-and-cut</collection>
    <collection role="institutes" number="">ZIB Allgemein</collection>
    <collection role="projects" number="MATHEON-B3">MATHEON-B3</collection>
    <file>https://opus4.kobv.de/opus4-zib/files/957/ZR-07-14.pdf</file>
    <file>https://opus4.kobv.de/opus4-zib/files/957/ZR-07-14.ps</file>
  </doc>
  <doc>
    <id>4745</id>
    <completedYear/>
    <publishedYear>2012</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>6</pageLast>
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    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Optimal Degree of Optical Circuit Switching in IP-over-WDM Networks</title>
    <abstract language="eng">In this paper, we study the influence of technology, traffic properties and price trends on optimized design of a reference IP-over-WDM network with rich underlying fiber topology. In each network node, we investigate the optimal degree of traffic switching in an optical (lambda) domain versus an electrical (packet) domain, also known as measure of \emph{node transparency}. This measure is studied in connection to changes in traffic volume, demand affinity, optical circuit speeds and equipment cost. By applying variable design constraints, we assess the relative roles of the two distinct equipment groups, IP routers and optical cross-connects, with respect to resulting changes in cost-sensitive network architectures.</abstract>
    <parentTitle language="eng">Optical Network Design and Modeling (ONDM), 2012 16th International Conference on</parentTitle>
    <identifier type="doi">10.1109/ONDM.2012.6210206</identifier>
    <enrichment key="PeerReviewed">yes</enrichment>
    <enrichment key="PreprintUrn">urn:nbn:de:0297-zib-14843</enrichment>
    <author>Ulrich Menne</author>
    <submitter> Engel</submitter>
    <author>Christian Raack</author>
    <author>Roland Wessäly</author>
    <author>Daniel Kharitonov</author>
    <collection role="institutes" number="optimization">Mathematical Optimization</collection>
    <collection role="institutes" number="aopt">Applied Optimization</collection>
  </doc>
  <doc>
    <id>3305</id>
    <completedYear>2007</completedYear>
    <publishedYear>2007</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>International Network Optimization Conference</publisherName>
    <publisherPlace>Spa, Belgium</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics</title>
    <parentTitle language="eng">Proceedings of the INOC 2007, Spa, Belgium, also ZIB Report ZR-06-47</parentTitle>
    <identifier type="url">http://www.zib.de/Publications/abstracts/ZR-06-47</identifier>
    <enrichment key="PreprintUrn">urn:nbn:de:0297-zib-9412</enrichment>
    <author>Sebastian Orlowski</author>
    <author>Arie M.C.A. Koster</author>
    <author>Christian Raack</author>
    <author>Roland Wessäly</author>
    <collection role="institutes" number="optimization">Mathematical Optimization</collection>
    <collection role="projects" number="BMBF-Eibone">BMBF-Eibone</collection>
    <collection role="institutes" number="aopt">Applied Optimization</collection>
  </doc>
  <doc>
    <id>3303</id>
    <completedYear>2007</completedYear>
    <publishedYear>2007</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>International Network Optimization Conference</publisherName>
    <publisherPlace>Spa, Belgium</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Capacitated network design using general flow-cutset inequalities</title>
    <parentTitle language="eng">Proceedings of the INOC 2007, Spa, Belgium, also ZIB Report ZR-07-14</parentTitle>
    <identifier type="url">http://www.zib.de/Publications/abstracts/ZR-07-14</identifier>
    <enrichment key="PreprintUrn">urn:nbn:de:0297-zib-9576</enrichment>
    <author>Christian Raack</author>
    <author>Arie M.C.A. Koster</author>
    <author>Sebastian Orlowski</author>
    <author>Roland Wessäly</author>
    <collection role="institutes" number="optimization">Mathematical Optimization</collection>
    <collection role="projects" number="BMBF-Eibone">BMBF-Eibone</collection>
    <collection role="institutes" number="aopt">Applied Optimization</collection>
  </doc>
  <doc>
    <id>3301</id>
    <completedYear>2008</completedYear>
    <publishedYear>2008</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>107</pageFirst>
    <pageLast>116</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>Polish-German Teletraffic Symposium</publisherName>
    <publisherPlace>Berlin, Germany</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Multi-layer network design – A model-based optimization approach</title>
    <parentTitle language="eng">Proceedings of the PGTS 2008, Berlin, Germany</parentTitle>
    <author>Andreas Bley</author>
    <author>Ulrich Menne</author>
    <author>Roman Klähne</author>
    <author>Christian Raack</author>
    <author>Roland Wessäly</author>
    <collection role="institutes" number="optimization">Mathematical Optimization</collection>
    <collection role="projects" number="100GET">100GET</collection>
    <collection role="projects" number="atesio">atesio</collection>
    <collection role="projects" number="MATHEON-B3">MATHEON-B3</collection>
    <collection role="institutes" number="aopt">Applied Optimization</collection>
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  <doc>
    <id>1484</id>
    <completedYear/>
    <publishedYear/>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>reportzib</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2012-03-19</completedDate>
    <publishedDate>2012-03-19</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Optimal Degree of Optical Circuit Switching in IP-over-WDM Networks</title>
    <abstract language="eng">In this paper, we study the influence of technology, traffic properties and price trends on optimized&#13;
design of a reference IP-over-WDM network with rich underlying fiber topology. In each network node,&#13;
we investigate the optimal degree of traffic switching in an optical (lambda) domain versus an electrical&#13;
(packet) domain, also known as measure of \emph{node transparency}. This measure is studied in connection to changes in &#13;
traffic volume,&#13;
demand affinity, optical circuit speeds and equipment cost. By applying variable design constraints,&#13;
we assess the relative roles of the two distinct equipment groups, IP routers and optical&#13;
cross-connects, with respect to resulting changes in cost-sensitive network architectures.</abstract>
    <identifier type="issn">1438-0064</identifier>
    <identifier type="urn">urn:nbn:de:0297-zib-14843</identifier>
    <identifier type="doi">10.1109/ONDM.2012.6210206</identifier>
    <enrichment key="SourceTitle">Appeared in: Proc. of the 16th conf. on optical network design and modeling ONDM  2012, pp. 1-6</enrichment>
    <author>Ulrich Menne</author>
    <submitter>Christian Raack</submitter>
    <author>Christian Raack</author>
    <author>Roland Wessäly</author>
    <author>Daniel Kharitonov</author>
    <series>
      <title>ZIB-Report</title>
      <number>11-50</number>
    </series>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>IP-over-WDM</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Circuit Switching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Opacity</value>
    </subject>
    <collection role="msc" number="90B18">Communication networks [See also 68M10, 94A05]</collection>
    <collection role="msc" number="90B20">Traffic problems</collection>
    <collection role="institutes" number="optimization">Mathematical Optimization</collection>
    <collection role="projects" number="atesio">atesio</collection>
    <collection role="projects" number="MATHEON-B3">MATHEON-B3</collection>
    <collection role="institutes" number="aopt">Applied Optimization</collection>
    <file>https://opus4.kobv.de/opus4-zib/files/1484/2012-03-19-ZIB-Report-11-50.pdf</file>
  </doc>
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