<div dir="ltr">Hi all,<div><br></div><div>This is a reminder of tomorrow's talk <span style="font-size:12.8px">"</span><span style="font-size:12.8px">Online Ensemble Learning of Data Streams with Gradually Evolved Classes" </span><span style="font-size:12.8px">Dr. </span><span class="gmail-il" style="background-color:rgb(255,255,255);font-size:12.8px">Leandro</span><span style="font-size:12.8px"> Minku (</span><a href="http://www.cs.le.ac.uk/people/llm11/" target="_blank" style="font-size:12.8px">http://www.cs.le.ac.uk/<wbr>people/llm11/</a><span style="font-size:12.8px">) (mb220, 2pm to 3pm).</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Best,</span></div><div><span style="font-size:12.8px">Luca</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 16 March 2017 at 15:16, Luca Rossi <span dir="ltr"><<a href="mailto:l.rossi@aston.ac.uk" target="_blank">l.rossi@aston.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear all,<div><br></div><div>The next CS seminar will be on Tuesday 21/03 from 2pm to 3pm in MB220.<br>Dr. Leandro Minku (<a href="http://www.cs.le.ac.uk/people/llm11/" target="_blank">http://www.cs.le.ac.uk/<wbr>people/llm11/</a>) will be giving a talk titled "<span style="font-size:12.8px">Online Ensemble Learning of Data Streams with Gradually Evolved Classes".</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Abstract:</span><br><span style="font-size:12.8px">In machine learning, class evolution is the phenomenon of class emergence and disappearance. It is likely to occur in many data stream problems, which are problems where additional training data become available over time. For example, in the problem of classifying tweets according to their topic, new topics may emerge over time, and certain topics may become unpopular and not discussed anymore. Therefore, class evolution is an important research topic in the area of learning data streams. Existing work implicitly regards class evolution as an abrupt change. However, in many real world problems, classes emerge or disappear gradually. This gives rise to extra challenges, such as non-stationary imbalance ratios between the different classes in the problem. In this talk, I will present an ensemble approach able to deal with gradually evolved classes. In order to quickly adjust to class evolution, the ensemble maintains a base learner for each class and dynamically creates, updates and (de)activates base learners whenever new training data become available. It also uses a dynamic undersampling technique in order to deal with the non-stationary class imbalance present in this type of problem. Empirical studies demonstrate the effectiveness of the proposed approach in various class evolution scenarios in comparison with existing class evolution approaches.<br></span><br>See you all next week,</div><div><div>Luca</div><span class="HOEnZb"><font color="#888888">-- <br><div class="m_-4809108251287310590gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr">Luca Rossi</div><div dir="ltr"><br></div><div dir="ltr">Lecturer in Computer Science</div><div dir="ltr">School of Engineering and Applied Science</div><div dir="ltr">Aston University</div><div dir="ltr">Web: <a href="http://www.cs.bham.ac.uk/~rossil/" target="_blank">http://www.cs.aston.ac.<wbr>uk/~rossil/</a></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr">Luca Rossi</div><div dir="ltr"><br></div><div dir="ltr">Lecturer in Computer Science</div><div dir="ltr">School of Engineering and Applied Science</div><div dir="ltr">Aston University</div><div dir="ltr">Web: <a href="http://www.cs.bham.ac.uk/~rossil/" target="_blank">http://www.cs.aston.ac.uk/~rossil/</a></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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