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• Design a novel storage and encryption algorithm to manage the keyword dictionary. • Greatly reduce both the dictionary reconstruction overhead and the file index re-encryption time as new keywords and files are added. • Design a novel trapdoor generation algorithm. • Take the keyword access frequencies into account when the system generates the ranked(More)
Clustering entities into dense parts is an important issue in social network analysis. Real social networks usually evolve over time and it remains a problem to efficiently cluster dynamic social networks. In this paper, a dynamic social network is modeled as an initial graph with an infinite change stream, called change stream model, which naturally(More)
Role mining from the existing permissions has been widely applied to aid the process of migrating to an RBAC system. While all permissions are treated evenly in previous approaches, none of the work has employed the weights of permissions in role mining to our knowledge, thus providing the motivation for this work. In this paper, we generalize this to the(More)
The current works about MapReduce task scheduling with deadline constraints neither take the differences of Map and Reduce task, nor the cluster’s heterogeneity into account. This paper proposes an extensional MapReduce Task Scheduling algorithm for Deadline constraints in Hadoop platform: MTSD. It allows user specify a job’s deadline and tries to make the(More)
Social tagging is an increasingly popular way to describe latent semantic information of web resources and thus is widely used to improve the performance of information retrieval system. However, there also has been significant variance of the quality of social tags because they can be annotated by folks on the web freely. As a consequence, how to measure(More)