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Many websites provide commenting facilities for users to express their opinions or sentiments with regards to content items, such as, videos, news stories, blog posts, etc. Previous studies have shown that user comments contain valuable information that can provide insight on Web documents and may be utilized for various tasks. This work presents a model(More)
The rise of smartphones and web services made possible the large-scale collection of personal metadata. Information about individuals' location, phone call logs, or web-searches, is collected and used intensively by organizations and big data researchers. Metadata has however yet to realize its full potential. Privacy and legal concerns, as well as the lack(More)
A new simple and efficient database encryption scheme is presented. The new scheme enables encrypting the entire content of the database without changing its structure. In addition, the scheme suggests how to convert the conventional database index to a secure index on the encrypted database so that the time complexity of all queries is maintained. No one(More)
The conventional way to speedup queries execution is by using indexes. Designing secure indexes for an encrypted database environment raises the question of how to construct the index so that no information about the database content is exposed. In this paper, the challenges raised when designing a secure index for an encrypted database are outlined; the(More)
This article describes the major challenges and design considerations pertaining to database encryption. The article first presents an attack model and the main relevant challenges of data security, encryption overhead, key management, and integration footprint. Next, the article reviews related academic work on alternative encryption configurations(More)
Persuasion is at the core of norm creation, emergence of collective action, and solutions to 'tragedy of the commons' problems. In this paper, we show that the directionality of friendship ties affect the extent to which individuals can influence the behavior of each other. Moreover, we find that people are typically poor at perceiving the directionality of(More)
Complex problem solving in science, engineering, and business has become a highly collaborative endeavor. Teams of scientists or engineers collaborate on projects using their social networks to gather new ideas and feedback. Here we bridge the literature on team performance and information networks by studying teams' problem solving abilities as a function(More)
Privacy Preserving Data Publishing (PPDP) is a research field that deals with the development of methods to enable publishing of data while minimizing distortion, for maintaining usability on one hand, and respecting privacy on the other hand. Sequential release is a scenario of data publishing where multiple releases of the same underlying table are(More)
Spam in Online Social Networks (OSNs) is a systemic problem that imposes a threat to these services in terms of undermining their value to advertisers and potential investors, as well as negatively affecting users' engagement. In this work, we present a unique analysis of spam accounts in OSNs viewed through the lens of their behavioral characteristics(More)