Learn More
Sybil accounts are fake identities created to unfairly increase the power or resources of a single user. Researchers have long known about the existence of Sybil accounts in online communities such as file-sharing systems, but have not been able to perform large scale measurements to detect them or measure their activities. In this paper, we describe our(More)
Popular online social networks (OSNs) like Facebook and Twitter are changing the way users communicate and interact with the Internet. A deep understanding of user interactions in OSNs can provide important insights into questions of human social behavior and into the design of social platforms and applications. However, recent studies have shown that a(More)
Peer-to-peer networks often use incentive policies to encourage cooperation between nodes. Such systems are generally susceptible to collusion by groups of users in order to gain unfair advantages over others. While techniques have been proposed to combat Web spam collusion, there are few measurements of real collusion in deployed systems. In this paper, we(More)
Skyline queries are capable of retrieving interesting points from a large data set according to multiple criteria. Most work on skyline queries so far has assumed a centralized storage, whereas in practice relevant data are often distributed among geographically scattered sites. In this work, we tackle constrained skyline queries in large-scale distributed(More)
Though a few previous research efforts have investigated the peer availability of P2P systems, the understanding of peer dynamic is far from adequate. Based on the running log of a file-sharing P2P system, we produced a more thorough measurement of the dynamic natures of P2P system. We further show that due to the methodology limitation, crawler based(More)
Much work has been done to address the need for incentive models in real deployed peer-to-peer networks. In this paper, we discuss problems found with the incentive model in a large, deployed peer-to-peer network, Maze. We evaluate several alternatives, and propose an incentive system that generates preferences for wellbehaved nodes while correctly(More)
Reputation systems are playing critical roles in securing today's distributed computing and communication systems. Similar to other security mechanisms, reputation systems can be under attack. In this paper, we report the discovery of a new attack, named RepTrap(Reputation Trap), against feedback-based reputation systems, such as those used in P2P(More)
Maze is a P2P file-sharing system with an active and large user base. It is developed, deployed and operated by an academic research team. As such, it offers ample opportunities to conduct experiments to understand user behavior. Embedded in Maze is a set of incentive policies designed to encourage sharing and contribution. This paper presents an in-depth(More)
As tools for personal storage, file synchronization and data sharing, cloud storage services such as Dropbox have quickly gained popularity. These services provide users with ubiquitous, reliable data storage that can be automatically synced across multiple devices, and also shared among a group of users. To minimize the network overhead, cloud storage(More)