César A. F. De Rose

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Cloud computing is a recent advancement wherein IT infrastructure and applications are provided as “services” to endusers under a usage-based payment model. They can leverage virtualized services even on the fly based on requirements (workload patterns and QoS) varying with time. The application services hosted under Cloud computing model have complex(More)
Cloud computing focuses on delivery of reliable, secure, fault-tolerant, sustainable, and scalable infrastructures for hosting Internet-based application services. These applications have different composition, configuration, and deployment requirements. Quantifying the performance of scheduling and allocation policy on a Cloud infrastructure (hardware,(More)
Virtualization has become a key technology for simplifying service management and reducing energy costs in data centers. One of the challenges faced by data centers is to decide when, how, and which virtual machines (VMs) have to be consolidated into a single physical server. Server consolidation involves VM migration, which has a direct impact on service(More)
The use of virtualization technologies in high performance computing (HPC) environments has traditionally been avoided due to their inherent performance overhead. However, with the rise of container-based virtualization implementations, such as Linux VServer, OpenVZ and Linux Containers (LXC), it is possible to obtain a very low overhead leading to(More)
Cloud computing has become a popular paradigm for implementing scalable computing infrastructures provided on-demand on a case-by-case basis. Selfmanageable Cloud infrastructures are required in order to comply with users’ requirements defined by Service Level Agreements (SLAs) and to minimize user interactions with the computing environment. Thus, adequate(More)
Cloud computing allows the deployment and delivery of application services for users worldwide. SaaS providers with limited upfront budget can take advantage of Cloud computing and lease the required capacity in a pay-as-you-go basis, which also enables flexible and dynamic resource allocation according to service demand. One key challenge potential Cloud(More)
Virtualization as a platform for resource-intensive applications, such as MapReduce (MR), has been the subject of many studies in the last years, as it has brought benefits such as better manageability, overall resource utilization, security and scalability. Nevertheless, because of the performance overheads, virtualization has traditionally been avoided in(More)
In general, two types of resource reservations in computer networks can be distinguished: immediate reservations which are made in a just-in-time manner and advance reservations which allow to reserve resources a long time before they are actually used. Advance reservations are especially useful for grid computing but also for a variety of other(More)
Cloud resources and services are offered based on Service Level Agreements (SLAs) that state usage terms and penalties in case of violations. Although, there is a large body of work in the area of SLA provisioning and monitoring at infrastructure and platform layers, SLAs are usually assumed to be guaranteed at the application layer. However, application(More)
For almost 30 years, computer memory systems have been essentially the same: volatile, high speed memory technologies like SRAM and DRAM used for cache and main memory; magnetic disks for high-end data storage; and persistent, low speed ash memory for storage with low capacity/low energy consumption requirements such as embedded/mobile devices. Today we(More)