Computational models of trust and reputation in online social networks Sana Hamdi To cite this version: Sana Hamdi. Computational models of trust and reputation in online social networks. Modeling and Simulation. Université Paris-Saclay; Université de Tunis. Faculté des sciences de Tunis, 2016. English. NNT : 2016SACLL001. tel-01274757 HAL Id: tel-01274757 https://tel.archives-ouvertes.fr/tel-01274757 Submitted on 16 Feb 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 1176$&// 7+(6('('2&725$7 GH /$)$&8/7('(66&,(1&(6'(781,6 HWGH /¶81,9(56,7(3$5,66$&/$< SUpSDUpHj7pOpFRP6XG3DULVHQ(YU\ e&2/('2&725$/(1 (FROH'RFWRUDOH6FLHQFHVHW7HFKQRORJLHVGHO ,QIRUPDWLRQHWGHOD&RPPXQLFDWLRQ 6SpFLDOLWpGHGRFWRUDW,QIRUPDWLTXH 3DU 0PH6DQD+DPGL &RPSXWDWLRQDO0RGHOVRI7UXVWDQG5HSXWDWLRQLQ2QOLQH6RFLDO1HWZRUNV 7KqVHSUpVHQWpHHWVRXWHQXHj(YU\OH-DQYLHU &RPSRVLWLRQGX-XU\ 0PH.:HJU]\Q:ROVND3URIHVVHXUH(6,*(7(/5DSSRUWHXVH 0PH+%HQ*KH]DOD3URIHVVHXUH(16,/D0DQRXED5DSSRUWHXVH 0PH%/H*UDQG3URIHVVHXUH8QLYHUVLWp3DULV6RUERQQH([DPLQDWULFH 0PH<%RXUGD3URIHVVHXUH&HQWUDOH6XSpOHF([DPLQDWULFH 000*DPPRXGL3URIHVVHXU,6$00/D0DQRXED([DPLQDWHXU 0PH$%RX]HJKRXE3URIHVVHXUH7pOpFRP6XG3DULV'LUHFWULFHGHWKqVH 06%HQ<DKLD3URIHVVHXU)677XQLV'LUHFWHXUGHWKqVH 0PH$/RSHV*DQFDUVNL0DvWUHGHFRQIpUHQFH7pOpFRP6XG3DULV(QFDGUDQWH i To my parents Kamel and Afifa I am especially thankful for your love and your continuous support. Thanks for always believing in me. I know you wait this special day from my birth. To my husband Nizar I am particularly indebted for your unconditional trust, support and sincere love. To my brother Ahmed To my sisters Meriem and Sonya To my niece Alma I love you! To my family in law I dedicate this work especially to my bambino Skander you accompanied me, in my belly, during writing this manuscript. I just adore you! ii Acknowledgements Throughout my Phd study period, many people have kindly provided me with their help and unlimited support. It is a pleasure to convey my most profound gratitude to them all and I am particularly indebted to the following people. First of all, I am grateful to my supervisor Pr. Sadok BEN YAHIA, for his continuous support and his constant guidance during my PhD study years in the LIPAH laboratory. Your encouragement and personal guidance have provided a good basis for the present thesis. Your perpetual energy and enthusiasm in research had motivated me so much. I am very fortunate to have you as a super- visor. Thank you for everything, it was a truly great experience working with you! Second, I would like to express my sincere appreciation to my supervisor Pr. Amel BOUZEGHOUB, for her warmly reception and insightful discussions and instructions during my research study. Under her supervision the quality of my work has constantly improved, not to mention the invaluable support and count- less contributions to this work. Thank you for having oriented and supported me with patience and encouragements, for your great sense of responsibility and professionalism. Thank you also for being understanding and for your support in many difficult times I lived during my PhD life. This work would have not been possible without the continuous support, advice, and encouragement from Mrs. Alda LOPES GANCARSKI. Throughout my PhD life, she has always been tireless in giving me invaluable comments and advice. Asides from work, she has also been exceptionally understanding and sympathetic with other problems I have encountered during this time. I express my greatest appreciation toward your guidance throughout the period of my study. I wish to thank also the members of the dissertation jury for accepting the invitation and their valuable time and feedback. My special appreciation goes to Pr. Henda Ben Ghezala, Pr. Katarzyna Wegrzyn-Wolska, Pr. Yolaine Bourda, Pr. Bénédicte Le Grand and Pr. Mohamed Mohsen Gammoudi. Many thanks to all my colleagues and friends inside Faculty of Sciences of Tunis iii and outside also for the excellent and truly enjoyable ambiance. My endless thanks to my husband and my family, for their endless care, under- standing, support, and advice on my personal life. iv Abstract Online Social Networks (OSNs) have known a dramatic increase and they have been used as means for a rich variety of activities. In fact, within OSNs, users are able to discover, extend, manage, and leverage their experiences and opinions online. However, the open and decentralized nature of the OSNs makes them vulnerable to the appearance of malicious users. Therefore, prospective users face many problems related to trust. Thus, effective and efficient trust evaluation is very crucial for users’ decision-making. It provides valuable information to OSNs users, enabling them to make difference between trustworthy and untrustworthy ones. This thesis aims to provide effective and efficient trust and reputation management methods to evaluate trust and reputation of OSNs users, which can be divided into the following four contributions. The first contribution presents a complex trust-oriented users’ contexts and interests extraction, where the complex social contextual information is taken into account in modelling, better reflecting the social networks in reality. In addition, we propose an enrichment of the Dbpedia ontology from conceptualizations of folksonomies. We second propose the IRIS (Interactions, Relationship types and Interest Sim- ilarity) trust management approach allowing the generation of the trust network and the computation of direct trust. This model considers social activities of users including their social relationships, preferences and interactions. The intention here is to form a solid basis for the reputation and indirect trust models. The third contribution of this thesis is trust inference in OSNs. In fact, it is necessary and significant to evaluate the trust between two participants whom have not direct interactions. We propose a trust inference model called TISON (Trust Inference in Social Networks) to evaluate Trust Inference within OSNs. The fourth contribution of this thesis consists on the reputation management in OSNs. To manage reputation, we proposed two new algorithms. We introduce a new exclusive algorithm for clustering users based on reputation, called RepC, based on trust network. In addition, we propose a second algorithm, FCR, which is a fuzzy extension of RepC. For the proposed approaches, extensive experiments have been conducted on real or random datasets. The experimental results have demonstrated that our proposed algorithms generate better results, in terms of the utility of delivered v results and efficiency, than do the pioneering approaches of the literature. Key words: Social networks; direct trust; indirect trust; reputation. vi Publications [1] Sana Hamdi, Alda Lopes Gancarski, Amel Bouzeghoub et Sadok Ben Yahia. Semantic Clustering of Users based on Shared Conceptualizations in Folk- sonomies. In Proceedings of the 3rd IEEE International Conference on Compu- tational Aspects of Social Networks (CASoN 2011), Salamanca, Spain, October 2011. [indexed IEEE, DBLP]. [2] Sana Hamdi, Alda Lopes Gancarski, Amel Bouzeghoub et Sadok Ben Yahia. IRIS: A Novel Method of Direct Trust Computation for Generating Trusted Social Networks. In Proceedings of the 11th IEEE International Confer- ence on Trust, Security and Privacy in Computing and Communications. (Trust- Com 2012), Liverpool, UK, June 2012. [indexed IEEE, DBLP], ERA rank A conference. [3] Sana Hamdi, Alda Lopes Gancarski, Amel Bouzeghoub et Sadok Ben Yahia. Enriching Ontologies from Folksonomies for eLearning: The DBpedia case. In Proceedings of the 12th IEEE International Conference on Advanced Learning Technologies. (ICALT 2012), Rome, Italy, July 2012. [indexed IEEE, DBLP], ERA rank B conference. [4] Sana Hamdi, Alda Lopes Gancarski, Amel Bouzeghoub et Sadok Ben Yahia. Enriching the DBpedia Ontology with Shared Conceptualizations from Folksonomies. In Proceedings of the 36th IEEE Signature Conference on Com- puters, Software, and Applications. (CompSac 2012), Izmir, Turkey, July 2012. [indexed IEEE, DBLP], ERA rank B conference. [5] Sana Hamdi, Amel Bouzeghoub, Alda Lopes Gancarski et Sadok Ben Yahia. Trust Inference computation for online Social Networks. In Proceedings of the 12th IEEE International Conference on Trust, Security and Privacy in Computing and Communications. (TrustCom 2013), Melbourne, Australia, July 2013. [indexed IEEE, DBLP], ERA rank A conference. vii [6] Sana Hamdi, Alda Lopes Gancarski, Amel Bouzeghoub et Sadok Ben Yahia. Linking Trust in Social Networks with the Semantic Web: FOAF Case. In Proceedings of the International Machine Learning and Data Analytics Sym- posium. (MLDAS 2015), Doha, Qatar, Mars 2015. The Best Paper Award. [7] Sana Hamdi, Alda Lopes Gancarski, Amel Bouzeghoub et Sadok Ben Yahia. TISON: Trust Inference in trust-oriented Social Networks. Transactions on Information Systems. In Press, Corrected Proof, 0 (2015), –. ERA rank A journal. Contents 1 Introduction 1 1.1 Social Networks and Trust Management . 3 1.2 Challenges in the Trust Management of OSNs . 3 1.2.1