Twitter added support for "@replies" beginning in May 2008,[3] with any combination of @ with a username being turned into a hyperlink to the profile. On March 30, 2009, Twitter updated the feature and renamed it "Mentions" (i.e., to "mention" user "@janedoe") so as to include non-reply posts directed at individual users.[4]
With pk=n_k/n being the fraction of the n_k samples from class k = {0,1} out of the total of n samples at node τ, the Gini impurity i(τ) is calculated as 1-p_0^2-p_1^2. The more discriminativ or clean a node is the lower is the value. A split will happen, if the decrease (delta_i) of the value is great for a given node. The gini decrease is the sum over all nodes in all trees of their delta_i's.
C. Drummond, and R. Holte. Proceedings of the Seventeenth International Conference on Machine Learning, page 239--246. San Francisco, CA, USA, Morgan Kaufmann Publishers Inc., (2000)
H. Bostrom. Proceedings of the Sixth International Conference on Machine Learning and Applications, page 211--216. Washington, DC, USA, IEEE Computer Society, (2007)
B. George, and S. Shekhar. Advances in Conceptual Modeling - Theory and Practice, volume 4231 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2006)
B. Macek, and M. Atzmueller. Proceeding ASONAM '13 Proceedings of the 2013 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining, page 1477-1478. ACM New York, (2013)
K. McCarthy, B. Zabar, and G. Weiss. Proceedings of the 1st international workshop on Utility-based data mining, page 69--77. New York, NY, USA, ACM, (2005)
H. Li, Y. Wang, D. Zhang, M. Zhang, and E. Chang. Proceedings of the 2008 ACM conference on Recommender systems, page 107--114. New York, NY, USA, ACM, (2008)
A. Popescul, R. Popescul, and L. Ungar. Workshop on Learning Statistical Models from Relational Data at the International Joint Conference on Articial Intelligence, (2003)
M. Rowe, M. Stankovic, and H. Alani. Proceedings of the 11th international conference on The Semantic Web - Volume Part I, page 476--491. Berlin, Heidelberg, Springer-Verlag, (2012)
L. Backstrom, and J. Leskovec. Proceedings of the fourth ACM international conference on Web search and data mining, page 635--644. New York, NY, USA, ACM, (2011)
Z. Yang, L. Hong, and B. Davison. Adaptivity, Personalization and Fusion of Heterogeneous Information, page 24--31. Paris, France, France, LE CENTRE DE HAUTES ETUDES INTERNATIONALES D'INFORMATIQUE DOCUMENTAIRE, (2010)
F. Kivran-Swaine, P. Govindan, and M. Naaman. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 1101--1104. New York, NY, USA, ACM, (2011)
H. Kwak, H. Chun, and S. Moon. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 1091--1100. New York, NY, USA, ACM, (2011)
H. Kwak, C. Lee, H. Park, and S. Moon. Proceedings of the 19th international conference on World wide web, page 591--600. New York, NY, USA, ACM, (2010)
J. Leskovec, J. Kleinberg, and C. Faloutsos. Proceedings of the eleventh ACM SIGKDD international conference on Knowledge discovery in data mining, page 177--187. New York, NY, USA, ACM, (2005)
H. Zhang, M. Korayem, E. You, and D. Crandall. Proceedings of the fifth ACM international conference on Web search and data mining, page 33--42. New York, NY, USA, ACM, (2012)
D. Liben-Nowell, and J. Kleinberg. Proceedings of the twelfth international conference on Information and knowledge management, page 556--559. New York, NY, USA, ACM, (2003)
D. Romero, B. Meeder, and J. Kleinberg. Proceedings of the 20th international conference on World wide web, page 695--704. New York, NY, USA, ACM, (2011)
T. Joachims. Proceedings of the eighth ACM SIGKDD international conference on Knowledge discovery and data mining, page 133--142. New York, NY, USA, ACM, (2002)