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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">***APOLOGIES IF YOU RECEIVE THIS MORE THAN ONCE***<o:p></o:p></p>
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<i><span style="font-size:24.0pt;color:#33A3A3;mso-fareast-language:ZH-CN">Applied Mathematics Seminar
</span></i><o:p></o:p></p>
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<span style="font-size:24.0pt;color:#76923C;mso-fareast-language:ZH-CN">Semester 2 – 2019</span><o:p></o:p></p>
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<p class="MsoBodyText" style="margin-bottom:0cm;margin-bottom:.0001pt"><b>Wednesday, 15 May at 12:00 in 07/3027</b><o:p></o:p></p>
<p class="MsoBodyText" style="margin-bottom:0cm;margin-bottom:.0001pt"><b>Mariano Beguerisse-Diaz (Spotify)</b><o:p></o:p></p>
<p class="MsoBodyText" style="margin-bottom:0cm;margin-bottom:.0001pt"><b>Continuous-time temporal networks with tie decay</b>
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<p class="MsoBodyText" style="margin-bottom:0cm;margin-bottom:.0001pt">In this talk I will present recent work on modelling networks from streams of interactions in continuous time. In these networks the weight of an edge represents the strength of a tie between
two nodes. Our modelling framework makes a distinction between interactions (discrete events at specific times) and ties (the strength of a relationship, which evolves in time). The two key modelling assumptions of this framework are: 1) In the absence of
interactions a tie between two nodes decays exponentially with rate alpha, and 2) when the nodes interact the tie experiences a discontinuous jump. The decay rate represents the deterioration rate of relationships and can be tuned to reflect a variety of scenarios.
Alternatively, tie decay can represent the diminishing value of old information. We introduce an adaptation of the popular PageRank centrality score to tie-decay networks, and provide an efficient algorithm to compute it in streaming data applications. We
illustrate these networks on synthetic examples, and a dataset of tweets about the NHS. Finally, we will discuss potential avenues for future research and other applications, such as recommendation systems<b>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">_____________________________________________<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Susan Davies<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Coordination Manager,
<a href="https://www.southampton.ac.uk/wsi/index.page?"><span style="color:#0563C1">Web Science Institute</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">University Liaison Manager,
<a href="https://www.southampton.ac.uk/wsi/alan-turing-institute/alan-turing-institute.page">
<span style="color:#0563C1">The Alan Turing Institute</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Room 3041, Building 32<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Web Science Institute<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">University of Southampton<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Southampton SO17 1BJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">023 8059 3523 | 07768 266464<o:p></o:p></span></p>
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