Jiangtao Zhang

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In role based access control (RBAC), minimizing the descriptive set of roles (specified as Basic-RMP) and minimizing the administrative assignments for roles (specified as Edge-RMP) can greatly decrease the management costs. Both role mining problems are proved to be NP-hard. In this work, we convert Basic-RMP to set cover problem and Edge-RMP to weighted(More)
In cloud computing, Some Cloud Service Providers (CSPs) have their own cloud infrastructure which is centralized or geographically distributed, small or large-scale. Others act as Brokers (CSBs) who integrate and launch services based on multiple CSPs' infrastructures. How to meet the complex requirements for different scenarios while provide high quality,(More)
Servers and network contribute about 60% to the total cost of data center in cloud computing. How to efficiently place virtual machines so that the cost can be saved as much as possible, while guaranteeing the quality of service plays a critical role in enhancing the competitiveness of service cloud provider. Considering the heterogeneous servers and the(More)
Cloud data centers provide all kinds of service using hundreds of thousands of servers. This naturally leads to concerns about the effect on environment such as carbon emissions and global warming. Huge amounts of effort have been devoted to power-aware scheduling using renewable energy. However, the intermittent availability of the renewable energy brings(More)