Tulip - reshaping trust management

Abstract

This thesis would have never become a reality without an enormous help of my two promotors: Sandro Etalle and Pieter Hartel. I am grateful to Sandro Etalle for countless number of things. First of all, I thank Sandro for his commitment to my work. I cannot recall a single moment, when I had the feeling that the work I was doing was not important to him. Sandro's honesty was an important driving force that helped me to retain self-confidence and belief in that I am able to finish this Ph.D. thesis. Everything I learnt about what a good technical paper should look like, and how to approach the difficult task of writing a good scientific paper professionally comes from Sandro. I wish every Ph.D. student to have this level of commitment and this level of knowledge from the promotor as I had from Sandro Etalle. I also would like to thank Sandro and his wife Nicole for warm reception in Trento. I would like to thank Pieter Hartel for giving me the opportunity of doing Ph.D. in his research group. Excellent working conditions, friendly atmosphere, and unbelievable level of flexibility in the working hours are the testimonies of Pieter's deep understanding for even highly eccentric Ph.D. student behaviour. I appreciate both Pieter's and his wife Marijke's concern to make us foreign students feel a bit more at home. I am especially thankful to Pieter for his involvement in improving both my written and spoken English. Regardless of the extent to which I met Pieter's expectations, I believe that my English is better than it was four years ago when I was starting my Ph.D. journey. Finally, I am impressed with Pieter's extra-natural ability to "process" hundreds of pages in only a few days and still being able to find not only spelling mistakes, but also technical inconsistencies that both me and Sandro overlooked. If there are any mistakes in this thesis, it is most certainly because I forgot to include some of the Pieter's comments. I thank Jeroen Doumen, who was my daily advisor for majority of time. I thank him for all discussions we had: it was very important to me. In a special way I am grateful to Jan Kuper for his enthusiasm in helping me to understand basics of mathematical logic during the individual course he gave me. I am often returning to his visualisations of the darkest corners of deductive systems. I also thank Jerry den Hartog. It was always a pleasure (and often the necessity) to "use" his sharp brain. In particular, I thank Jerry that he spontaneously agreed to provide the Dutch translation of the summary of this thesis. I would like to thank Mehmet Akşit, Krzysztof Apt, Willem Jonker, Marten van Sinderen, Sabrina De Capitani Di Vimercati, and Will Winsborough for accepting the invitation to be part of the graduation committee of this thesis. It is a great honour for me. I thank the Freeband consortium for the funding for my research. In particular, I would like to acknowledge all the members of the I-Share project, especially Inald Lagendijk, Dick Epema, Johan Pouwelse, Arno Bakker, and Jan-David Mol. I ...

LP with Flexible Grouping and Aggregates Using Modes

“…In TuLiP, the first rule is called a credential, the second rule is a user-defined constraint [8]. Assume that there exist the following credentials:…”

“…For instance, if one of the recommends(...) credentials is not found, the query would fail, which means that marcin would not be able to read the document even though he has sufficient permissions. One of the things we try to handle in TuLiP [8,9,10] is where to store the credentials so that they can be found later during the credential discovery. If we assume that mode(read_document) = mode(partner) = mode(senior) = mode(recommends) = (In, Out) and mode(senior_recommends) = (In, Out, Out) then, by the credential storage principles of TuLiP, all the credentials and the user-defined constraint will be stored by their issuers (indicated by the first argument of a credential atom).…”

“…Grouping and aggregation are useful in practice, and paramount in database systems. In fact, the reason why we address the problem here is of a practical nature: we are developing a language for trust management [5,7,18] called TuLiP [8,9,10]. TuLiP is based on (partially function-free) moded logic programming, in which a logic program is augmented with an indication of which are the input and the output positions of each predicate.…”