Sérgio Lifschitz

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In this work, we used the PROV-DM model to manage data provenance in workflows of genome projects. This provenance model allows the storage of details of one workflow execution, e.g., raw and produced data and computational tools, their versions and parameters. Using this model, biologists can access details of one particular execution of a workflow,(More)
In this work we investigate the parallel evaluation of BLAST, the most popular tool for comparing biological sequences. Our goal is to study database distribution issues that, besides workload balancing, could improve the performance of a set of BLAST processes running in a workstation cluster. We consider different partitioning strategies within actual(More)
Mobile computing allows for the development of new and sophisticated database applications. Such applications require the reading of current and consistent data. In order to improve data availability, increase performance and maximize throughput, data replication is used. However, due to inherent limitations in mobile and other loosely-coupled environments,(More)
This work presents the core ideas for an approach that enables index tuning with no human intervention at all. SQL statements submitted to the database are monitored and indices are created or dropped according to the benefits or overheads regarding the actual workload. We have implemented this strategy using a software agent architecture embedded in(More)
We study a dose-driven dynamic load balancing strategy to evaluate database recursive queries. This proposal aims at obtaining a good workload balance with full use of the available resources, with different kinds of skew considered. The strategy is intended for general recursive queries and preliminary computational results illustrate its ef-ciency when(More)
Knowledge representation in the biological domain suffers from two main difficulties that make it hard to apply traditional conceptual modeling tools: the inherent domain complexity and its constant evolution. The former requires complex types and associations, whereas the latter calls for an expressive language. We list in this paper a set of requirements(More)
A brief pulse of red light (R) given to darkgrown seedlings ofArabidopsis thaliana (L.) Heyn. potentiates rapid synthesis of chlorophyll upon transfer to continuous white light. The time course for potentiation of rapid greening shows that a R pulse in the LF (low fluence) range has maximal effect within a few hours, and that there is a small VLF (very low(More)