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Demands on software reliability and availability have increased due to the nature of present day applications. Cloud computing systems fundamentally provide access to large pools of data and computational resources through a variety of interfaces similarly to existing grid and HPC resource management and programming systems. This work investigates the(More)
Mobile cloud computing is a new paradigm that uses cloud computing resources to overcome the limitations of mobile computing. Due to its complexity, dependability and performance studies of mobile clouds may require composite modeling techniques, using distinct models for each subsystem and combining state-based and non-state-based formalisms. This paper(More)
High availability in cloud computing services is essential for maintaining customer confidence and avoiding revenue losses due to SLA violation penalties. Since the software and hardware components of cloud infrastructures may have limited reliability, the use of redundant components and multiple clusters may be required to achieve the expected level of(More)
Performance evaluation of mobile applications has received considerable attention as a prominent activity for improving services quality. Because many data stored on mobile device are synchronized with distributed data centers, the system availability is a critical attribute that requires investigation. Mobile backend-as-a-service (MBaaS) allows developers(More)
The introduction of legumes and nitrogen-fixing bacteria in tropical areas under pasture is a key factor for improvement of soil fertility. However, there are still very few studies concerning the symbionts of tropical forage legumes. We performed a polyphasic study with three strains representing the genus Bradyrhizobium (BR 446T, BR 510 and BR 511)(More)
TonB-dependent receptors in concert with the TonB–ExbB–ExbD protein complex are responsible for the uptake of iron and substances such as vitamin B12 in several bacterial species. In this study, Tn5 mutagenesis of the sugarcane endophytic bacterium Gluconacetobacter diazotrophicus led to the isolation of a mutant with a single Tn5-insertion in the promoter(More)
The need for reliability and availability has increased in modern applications, which need to handle rapidly growing demands while providing uninterrupted service. This work investigates the memory leak and memory fragmentation aging effects on the Eucalyptus cloud-computing framework, which considers workloads composed of intensive requests addressing(More)