
We are proud to announce that Marcello Ribeiro successfully defended his Ph.D. thesis, “An Approach for Scheduling Scientific Workflows in Hybrid VM–Serverless Cloud Environments,” on October 6 and is now the newest Doctor at the Instituto de Computação at Universidade Federal Fluminense (IC/UFF).
We are proud to announce that Marcello Ribeiro successfully defended his Ph.D. thesis, “An Approach for Scheduling Scientific Workflows in Hybrid VM–Serverless Cloud Environments,” on October 6 and is now the newest Doctor at the Instituto de Computação at Universidade Federal Fluminense (IC/UFF). Workflows increasingly execute on elastic cloud infrastructures, where serverless functions now coexist with traditional Virtual Machines. Each model has its own performance, pricing, and operational constraints, so a scheduler must decide not only when each activation runs, but also where. Marcello’s thesis tackles this underexplored heterogeneous scheduling problem with three complementary contributions: 🔹 Denethor, a provenance capture system for workflows running on serverless platforms, providing empirical execution time and cost data; 🔹 FLEXE+IP, an integer programming model that formulates the scheduling problem; 🔹 FLEXE+, a GRASP-based heuristic with VND local search that jointly chooses the execution environment and the execution order, balancing makespan and financial cost. Experiments with synthetic workflows and a large-scale real bioinformatics workflow show that FLEXE+ reduces makespan or cost depending on the prioritized objective, while reaching near-optimal solutions on instances where the exact model is tractable. Marcello, thank you for your dedication and for all the contributions you brought to our group over these years. Well deserved! Marcello was advised by Profs. Daniel de Oliveira and (UFF) Isabel Rosseti (UFF). Our thanks to the examiners for the insightful discussion: Simone Martins, Yuri Frota (UFF), Marta Mattoso (COPPE/UFRJ), Luan Teylo (INRIA), Rafaelli Coutinho (Cefet/RJ), and UBIRATAM CARVALHO DE PAULA JUNIOR (UFRRJ). #PhD #CloudComputing #Serverless #ScientificWorkflows #Scheduling #Metaheuristics #UFF #eScience
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