Recommender Systems for Social Bookmarking PROEFSCHRIFT ter verkrijging van de graad van doctor an de universiteit van Tilburg gezag van prof. dr. Ph. Eijlander in het openbaar te verdedigen ten overstaan van een door het college voor promotes aangewezen commissie in de aula van de universiteit op dinsdag 8 december 2009 om 14.15 uur door Antonius Marinus Bogers geboren op 21 september 1979 te Roosendaal en Nispen
Recommender Systems for Social Bookmarking PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Universiteit van Tilburg, op gezag van de rector magnificus, prof. dr. Ph. Eijlander, in het openbaar te verdedigen ten overstaan van een door het college voor promoties aangewezen commissie in de aula van de Universiteit op dinsdag 8 december 2009 om 14.15 uur door Antonius Marinus Bogers, geboren op 21 september 1979 te Roosendaal en Nispen
Promotor Prof dr. A.pj. van den bosch Beoordelingscommissie Prof dr h.j. van den herik Prof dr M. de Rijke Prof dr L boves Dr B. Larsen The research reported in this thesis has been funded by SenterNovem /the Dutch Ministry of Economic Affairs as part of the IOP-MMI A Propos project SIKS Dissertation Series No. 2009-42 The research reported in this thesis has been carried out under the auspices of SIKS, the Dutch Research School for Information and Knowledge Systems Tice TiCC Dissertation Series No. 10 ISBN97890-8559582-3 Copyright 2009, A M. Bogers All rights reserved. No part of this publication may be reproduced, stored in a retrieval sys tem, or transmitted, in any form or by any means, electronically, mechanically, photocopying, recording or otherwise, without prior permission of the author
Promotor: Prof. dr. A.P.J. van den Bosch Beoordelingscommissie: Prof. dr. H.J. van den Herik Prof. dr. M. de Rijke Prof. dr. L. Boves Dr. B. Larsen Dr. J.J. Paijmans The research reported in this thesis has been funded by SenterNovem / the Dutch Ministry of Economic Affairs as part of the IOP-MMI À Propos project. SIKS Dissertation Series No. 2009-42 The research reported in this thesis has been carried out under the auspices of SIKS, the Dutch Research School for Information and Knowledge Systems. TiCC Dissertation Series No. 10 ISBN 978-90-8559-582-3 Copyright c 2009, A.M. Bogers All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronically, mechanically, photocopying, recording or otherwise, without prior permission of the author
GC The Web, they say, is leaving the era of search and entering one of discovery. thing. Discovery is when something wonderful that you didn 't know existed, or didn 't know how to ask for, finds you Jeffrey M. o'Brien
“ The Web, they say, is leaving the era of search and entering one of discovery. What’s the difference? Search is what you do when you’re looking for something. Discovery is when something wonderful that you didn’t know existed, or didn’t know how to ask for, finds you. ” Jeffrey M. O’Brien
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PREFACE First and foremost I would like to thank my supervisor and promotor Antal van den bosch who guided me in my first steps as a researcher, both for my Masters thesis and my Ph. D research. Antal always gave me free reign in investigating many different research prob- lems, while at the same time managing to steer me in the right direction when the time called for it. Antal was always able to make time for me or any of the other Ph. D. students and read and comment on paper or presentation drafts In addition to turning me into a better researcher, Antal was also instrumental in improving my Guitar Hero skills. Our thesis meetings during your sabbatical doubled as a kind of Rock n Roll Fantasy Camp, where we could both unwind from discussing yet another batch of experiments I had run or was planning to run. Rock on! Antal also shares my passion for ice hockey. This resulted in us attending Tilburg Trappers games in Stappegoor as well as our regular discussions of the latest hockey news. Thanks for inviting me to come see the HL All Star games in Breda. Hopefully we will meet again in spirit come May 2010 when the Canucks beat the Penguins in the Stanley Cup finals! The research presented in this thesis was performed in the context of the a Propos project I would like to acknowledge SenterNovem and the Dutch Ministry of Economic Affairs for funding this project as part of the IOp-MMI program. The a Propos project was started by Lou Boves, Antal, and Frank Hofstede. I would like to thank Lou and Frank in particular. Frank was always able to look at my research problems from a different and more practical angle, and as a result our discussions were always very stimulating. I would also like to Mari Carmen Puerta-Melguizo, Anita Deshpande, and Els den Os, as well as the other members and attendees of the project meetings for the pleasant cooperation and helpful comments and suggestions I wish to thank the members of my committee for taking time out of their busy schedules to read my dissertation and attending my defense: Jaap van den Herik, Maarten de Rijke, Lou Boves, Birger Larsen, and Hans Paijmans. Special thanks go to Jaap for his willingness to go through my thesis with a fine-grained comb. The readability of the final text has benefited greatly from his meticulous attention to detail and quality. Any errors remaining in the thesis are my own. I would also like to thank Birger for his comments, which helped to dot the is and cross the ts of the final product. Finally, I would like to thank Hans Paijmans who contributed considerably to my knowledge of IR. IV
PREFACE First and foremost I would like to thank my supervisor and promotor Antal van den Bosch, who guided me in my first steps as a researcher, both for my Master’s thesis and my Ph.D. research. Antal always gave me free reign in investigating many different research problems, while at the same time managing to steer me in the right direction when the time called for it. Antal was always able to make time for me or any of the other Ph.D. students, and read and comment on paper or presentation drafts. In addition to turning me into a better researcher, Antal was also instrumental in improving my Guitar Hero skills. Our thesis meetings during your sabbatical doubled as a kind of Rock ’n Roll Fantasy Camp, where we could both unwind from discussing yet another batch of experiments I had run or was planning to run. Rock on! Antal also shares my passion for ice hockey. This resulted in us attending Tilburg Trappers games in Stappegoor as well as our regular discussions of the latest hockey news. Thanks for inviting me to come see the NHL All Star games in Breda. Hopefully we will meet again in spirit come May 2010 when the Canucks beat the Penguins in the Stanley Cup finals! The research presented in this thesis was performed in the context of the À Propos project. I would like to acknowledge SenterNovem and the Dutch Ministry of Economic Affairs for funding this project as part of the IOP-MMI program. The À Propos project was started by Lou Boves, Antal, and Frank Hofstede. I would like to thank Lou and Frank in particular. Frank was always able to look at my research problems from a different and more practical angle, and as a result our discussions were always very stimulating. I would also like to Mari Carmen Puerta-Melguizo, Anita Deshpande, and Els den Os, as well as the other members and attendees of the project meetings for the pleasant cooperation and helpful comments and suggestions. I wish to thank the members of my committee for taking time out of their busy schedules to read my dissertation and attending my defense: Jaap van den Herik, Maarten de Rijke, Lou Boves, Birger Larsen, and Hans Paijmans. Special thanks go to Jaap for his willingness to go through my thesis with a fine-grained comb. The readability of the final text has benefited greatly from his meticulous attention to detail and quality. Any errors remaining in the thesis are my own. I would also like to thank Birger for his comments, which helped to dot the i’s and cross the t’s of the final product. Finally, I would like to thank Hans Paijmans, who contributed considerably to my knowledge of IR. iv