Cipriano A. Santos

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Losing information when a storage device or data center fails can bring a company to its knees—or put it out of business altogether. Such catastrophic outcomes can readily be prevented with today’s storage technology, albeit with some difficulty: the design space of solutions is surprisingly large, the configuration choices are myriad, and the alternatives(More)
Restoring data operations after a disaster is a daunting task: how should recovery be performed to minimize data loss and application downtime? Administrators are under considerable pressure to recover quickly, so they lack time to make good scheduling decisions. They schedule recovery based on rules of thumb, or on pre-determined orders that might not be(More)
We describe a new class of utility-maximization scheduling problem with precedence constraints, the <i>disconnected staged scheduling problem</i> (DSSP). DSSP is a nonpreemptive multiprocessor deadline scheduling problem that arises in several commercially-important applications, including animation rendering, protein analysis, and seismic signal(More)
Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides (Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was(More)
In this paper, we describe a resource assignment problem (RAP) for a large-scale computing utility, such as an Internet data center. The problem is defined as follows: For a given topology of a network consisting of switches and servers with varying capabilities, and for a given application with a distributed architecture, decide which server from the(More)
This paper describes the association of two bioreactors: one photoautotrophic and the other heterotrophic, connected by the gas phase and allowing an exchange of O2 and CO2 gases between them, benefiting from a symbiotic effect. The association of two bioreactors was proposed with the aim of improving the microalgae oil productivity for biodiesel(More)
In this paper, we address the resource allocation problem (RAP) for large scale data centers using mathematical optimization techniques. Given a physical topology of resources in a large data center, and an application with certain architecture and requirements, we want to determine which resources in the physical topology should be assigned to the(More)
Utility computing is envisioned as the future of enterprise IT environments. Achieving utility computing is a daunting task, because enterprise users have diverse and complex needs. In this paper we describe quartermaster, an integrated set of tools that addresses some of these needs. Quartermaster supports the entire lifecycle of computing tasks -(More)
Many systems design, configuration, runtime and management decisions must be made from a large set of possible alternatives. Ad hoc heuristics have traditionally been used to make these decisions, but they provide no guarantees of solution quality. We argue that operations research-style optimization techniques should be used to solve these problems. We(More)