This is the last of the three posts about recommendation systems, the first can be found here, the second here. In order to validate the effectiveness of our approach we decided to make an experiment with actual products and users. For this purpose we collected from a french medias reviews website krinein a sample of 4400 movies.  From these 4400 movies, we selected uniformly at random 160 of them. This was the data set for our experiment. We then extract uniformly at random from this data set 9 movies. These 9 movies were our witness products set. Our methodology was […]

This post is highly inspired from the introduction of a research paper, written by Sébastien Hémon, Thomas Largillier and myself, entitled Partial ranking of products for recommendation systems. Recommending products to customers is a field far older than computer science.  With the tremendous increase of the commercial potential of the e-commerce it has become of the utmost importance to perform well in this field.  Moreover, companies have now the ability to store information about consumption habits of customer: their previous purchases, their tastes. They also have access to information that often allows to cluster customers into communities that share some […]

The category Nice infographics is here to present nice infographics (no kidding!) without comments. I found this one one a french blog, it presents the growth of Internet (click on the image to enlarge it).

Jose Quesada is a cognitive science researcher working at the Adaptive Behavior and Cognition group, Max Planck Institute, Berlin. He’s  writing about productivity and research in a blog entitled « academic productivity« . I cannot really say that I agree with what he writes in his blog. Even if he focuses on productivity in an academic environment, there is no solid justification of why being productive is important. Nevertheless Jose says on his home page:  » I express what I think it is to do conscious science in the 21st century. It may not be what most people think « . I do […]

This is the last of the 3 posts about SpotRank. In this one I show some evidence of the effiency of the method. Even with a very strong analysis of the log files, it is impossible to  judge the quality of the filtering of our method. Indeed, the algorithm consists in filtering news w.r.t. the way people vote, it is not content related. To cope with this issue we decided to gather some feedback from the users themselves.  Since an absolute judgement is impossible to obtain without a long debate on what is the quality of a website, we choose […]

In this post I give a short overview of SpotRank, an algorithm designed by Thomas Largillier, Guillaume Peyronnet and Myself. The goal of SpotRank is to offer a voting mechanism for social news website (such as Digg for instance) which is robust to manipulation attempts by malicious users. Again the post is highly inspired by our research paper. A previous post introduced social news websites and related issues. We consider that the voting system SpotRank is used by a community of users that can propose its own news (or content), that we will call spots. Any user of the community […]

This post is a part of the introduction of an academic paper coauthored by Thomas Largillier, Guillaume Peyronnet and Myself. I did some modifications, so I endorse all mistakes of this version. In the last years, the way people interact with each others on the Web has drastically changed. Web sites now provide information which is an aggregation of user-generated content, generally filtered using social recommendation methods to suggest relevant documents to users.  The most known example of such a website is Digg. This is a social news website: people share content they found on the web through the Digg […]

My name is Sylvain Peyronnet. I am an Assistant Professor of Computer Science at Paris-Sud University since 2007. I am doing my research at LRI (Laboratoire de Recherche en Informatique – Computer Science Lab in English) and my teaching at IFIPS (school of engineering of the university). I joined the university after a period of 4 years in various positions: postdoc, assistant professor in a private university, entrepreneur. I earn a Ph.D. in computer science from Paris-Sud University in 2003 (yes, I came back to the same university after 4 years). I am broadly interested in applications of probabilistic and […]

C’est étonnant mais je n’ai vu nulle part dans le petit milieu des fans de captchas la moindre mention du travail des googlers que l’on trouve présenté sur le post suivant du research blog de Google : http://googleresearch.blogspot.com/2009/04/socially-adjusted-captchas.html. Les fameux « captchas ajustés socialement » sont expliqués en détail dans l’article suivant : Rich Gossweiler, Maryam Kamvar and Shumeet Baluja. What’s Up CAPTCHA? A CAPTCHA Based on Image Orientation. International World Wide Web Conference 2009, (WWW 2009). Pourquoi chercher un nouveau mécanisme ? Parce que selon les auteurs les spammeurs sont en train de gagner la guerre des captchas : […]

Un petit post rapide pour vous évoquer le classement des sites web français délivré par l’association pour le contrôle de la diffusion des médias (OJD, le classement est ici). Je l’ai découvert au détour d’un tout petit article d’à peine 15 lignes dans l’édition papier du Monde (page 15 de l’édition du 13 juin) et je suis allé voir sur le web car l’article papier est particulièrement nombriliste et sans analyse, comme quoi l’édition papier va finir par rejoindre la version web du journal point de vue qualité si ça continue. Je dois le dire ce classement est pour moi […]