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<journal-meta>
<journal-id journal-id-type="publisher-id">INFORMATICA</journal-id>
<journal-title-group><journal-title>Informatica</journal-title></journal-title-group>
<issn pub-type="epub">0868-4952</issn><issn pub-type="ppub">0868-4952</issn>
<publisher>
<publisher-name>VU</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="publisher-id">INFO1094</article-id><article-id pub-id-type="doi">10.15388/Informatica.2016.86</article-id>
<article-categories><subj-group subj-group-type="heading">
<subject>Research Article</subject></subj-group></article-categories>
<title-group>
<article-title><italic>CoRSO</italic> (Collaborative Reactive Search Optimization): Blending Combinatorial and Continuous Local Search</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="Author">
<name><surname>Brunato</surname><given-names>Mauro</given-names></name><email xlink:href="mailto:mauro.brunato@unitn.it">mauro.brunato@unitn.it</email><xref ref-type="aff" rid="j_INFORMATICA_aff_000"/>
</contrib>
<contrib contrib-type="Author">
<name><surname>Battiti</surname><given-names>Roberto</given-names></name><email xlink:href="mailto:roberto.battiti@unitn.it">roberto.battiti@unitn.it</email><xref ref-type="aff" rid="j_INFORMATICA_aff_000"/><xref ref-type="corresp" rid="cor1">*</xref>
</contrib>
<aff id="j_INFORMATICA_aff_000">Department of Information Engineering and Computer Science, University of Trento, Italy</aff>
</contrib-group>
<author-notes>
<corresp id="cor1"><label>*</label>Corresponding author.</corresp>
</author-notes>
<pub-date pub-type="epub"><day>01</day><month>01</month><year>2016</year></pub-date><volume>27</volume><issue>2</issue><fpage>299</fpage><lpage>322</lpage><history><date date-type="received"><day>01</day><month>12</month> <year>2015</year></date><date date-type="accepted"><day>01</day><month>04</month> <year>2016</year></date></history>
<permissions><copyright-statement>Vilnius University</copyright-statement><copyright-year>2016</copyright-year></permissions>
<abstract>
<p>We propose a heuristic global optimization technique which combines combinatorial and continuous local search. The combinatorial component, based on Reactive Search Optimization, generates a trajectory of binary strings describing search districts. Each district is evaluated by random sampling and by selective runs of continuous local search. A reactive prohibition mechanisms guarantees that the search is not stuck at locally optimal districts.</p>
<p>The continuous stochastic local search is based on the <italic>Inertial Shaker</italic> method: candidate points are generated in an adaptive search box and a moving average of the steps filters out evaluation noise and high-frequency oscillations.</p>
<p>The overall subdivision of the input space in a tree of non-overlapping search districts is adaptive, with a finer subdivision in the more interesting input zones, potentially leading to lower local minima.</p>
<p>Finally, a portfolio of independent <italic>CoRSO</italic> search streams (<italic>P-CoRSO</italic>) is proposed to increase the robustness of the algorithm.</p>
<p>An extensive experimental comparison with Genetic Algorithms and Particle Swarm demonstrates that <italic>CoRSO</italic> and <italic>P-CoRSO</italic> reach results which are fully competitive and in some cases significantly more robust.</p>
</abstract>
<kwd-group>
<label>Keywords</label>
<kwd>global optimization</kwd>
<kwd>reactive search optimization</kwd>
<kwd>algorithm portfolios</kwd>
</kwd-group>
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