Clouds describe a new resource consumption and delivery model for web applications by providing dynamically scalable and virtualized resources as service over the Internet to meet specified capacity, performance and budget needs etc. Resource provisioning for N-tier web applications in Clouds is non-trivial: first, the complexity of web applications makes it difficult to predict performance in the face of dynamic workloads for potential resources allocation; second, dynamic provisioning of virtual resources entails an inherent performance-cost trade-off, in which a well-design scheduling scheme can achieve the well performance for a given resource budget, minimizing resource cost and maximizing utilization without compromising service performance.
In Xi's work, a novel profit-driven scheduling technique for N-tier web application was proposed that employs (i) a performance model to analyze and predict such application and provide insight into application's behavior to determine how much resources to allocate to each tier of the application, and (ii) a novel profit-driven provisioning technique to determines when to remove or add virtual resource and maximize profits of SaaS providers. Her paper is published at the 2011 IEEE International Conference on Cloud and Service Computing (CSC 2011), Hong Kong.
The above picture was shot when she was presenting her work at the conference.