Haralambie Leahu

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Commercial cloud offerings, such as Amazon’s EC2, let users allocate compute resources on demand, charging based on reserved time intervals. While this gives great flexibility to elastic applications, users lack guidance for choosing between multiple offerings, in order to complete their computations within given budget constraints. In this work, we present(More)
Elastic applications like bags of tasks benefit greatly from Infrastructure as a Service (IaaS) clouds that let users allocate compute resources on demand, charging based on reserved time intervals. Users, however, still need guidance for mapping their applications onto multiple IaaS offerings, both minimizing execution time and respecting budget(More)
In this paper, we study cost functions over a finite collection of random variables. For these types of models, a calculus of differentiation is developed that allows us to obtain a closed-form expression for derivatives where “differentiation” has to be understood in the weak sense. The technique for proving the results is new and establishes an(More)
A very wide variety of physical, demographic, biological and man-made phenomena have been observed to exhibit powerlaw behavior, including the population of cities and villages, sizes of lakes, etc. The Internet is no exception to this. The connectivity of routers, the popularity of web sites, and the degrees of World Wide Web pages are only a few examples(More)
In this paper we provide a smoothed perturbation analysis (SPA) of the sensitivity of a discrete time Parisian option with respect to the barrier level. The analysis put forward is of interest in a broader context than that of exotic options as we provide an SPA analysis for a problem where the critical event for the SPA estimator is based on an entire(More)