Leonardo O. Moreira

Scale-Space Filtering for Workload Analysis and Forecast

Dynamic resource provisioning poses a major challenge for infrastructure providers because it is necessary to both forecast resource consumption and react to recent surges on demand for maintaining a tradeoff between quality of service and cost. However, approaches to workload analysis and forecast are affected due to noise in observed data, specially in forecast models. Moreover, most studies do not consider different prediction horizons may be necessary in order to take action before an SLA violation occurs. This paper presents an approach based in the scale-space theory to assist the dynamic resource provisioning. This theory is capable of eliminating the presence of irrelevant information from a signal that can potentially induce wrong or late decision making. In order to evaluate our approach, some experiments are presented considering both reactive and proactive strategies. The results confirm that our approach improves the workload analysis and forecast.

A distributed concurrency control mechanism for XML data

XML has become a widely used standard for data exchange among applications. Consequently, a large amount of data is distributed on the Web and stored in different persistence models. DBMSs provide concurrency control techniques to manage such data. However, the structure of XML data makes the application of these techniques difficult. Regarding distributed environments, there are few papers available and they all have limitations. This paper introduces DTX, a mechanism for distributed concurrency control for XML data. In order to evaluate DTX, experiments that measure its performance are presented.

A Distributed Concurrency Control Mechanism for XML Data

XML has become a widely used standard for data exchange among applications. Consequently, a large amount of data is distributed on the Web and stored in different persistence models. DBMSs provide concurrency control techniques to manage such data. However, the structure of XML data makes the application of these techniques difficult. Regarding distributed environments, there are few papers available and they all have limitations. This paper introduces DTX, a mechanism for distributed concurrency control for XML data. In order to evaluate DTX, experiments that measure its performance are presented.

A Platform as a Service Billing Model for Cloud Computing Management Approaches

Platform as a Service (PaaS) billing needs an effective billing strategy. In this paper we proceeded a literature review and proposed a new billing model for a PaaS provider. Our billing model allows charges to PaaS clients in several policies, from specific plans to fully pay-per-use. We automated our billing model in a monitoring and management software tool. The model and the tool were validated through a case study in a software development company. The results indicated that our model is useful and preferable in relation to current billing policies and can be used in PaaS management.

GameVis: Game Data Visualization for the Web

Gaming and eSports have become increasingly popular and complex. For that reason, it is necessary that tournament hosts and game developers provide a great amount of meaningful information for their audiences. Data visualization tools and frameworks are of upmost importance since these provides means to accomplish this task. In this paper we propose GameVis, a framework designed to aid developers in building game data visualization components for the Web. GameVis allows multiple data formats to be translated into a single data structure that can be extended and customized in many ways, allowing visualizations to suit different screen sizes and platforms while showing a great amount of variation and meaning. Visualizations built within the framework may feature animations, annotations and might even adapt to different visual themes in order to provide a richer, more interactive user experience. This is shown through experimental results.

Towards improvements on the quality of service for multi-tenant RDBMS in the cloud

Cloud computing is a trend of technology aimed at providing on-demand services with payment based on usage. To improve the use of resources, cloud providers adopt multi-tenant approaches, reducing the operation cost of services. Moreover, tenants have irregular workload patterns, impacting in the guarantees of quality of service, mainly due to interference between tenants. This paper proposes an approach to improve quality of service for multi-tenant RDBMS. This approach employs migration techniques of tenants, system monitoring, allocation strategy, forecast approach, and benefits of cloud infrastructure to improve performance and reduce provider cost. We carried out experiments on performance and resource usage in order to evaluate it.

How to deploy a virtual learning environment in the cloud

Cloud computing is a trend of technology aimed at providing on-demand services with payment based on usage. Virtual Learning Environments (VLEs) are applications that require a highly scalable architecture that provides for its users an acceptable level of Quality of Service (QoS). This work aims to show the steps needed to install a VLE in a cloud computing infrastructure. The VLEs migration to this new type of execution environment allows the increase of its use but also brings some performance issues that must be considered. The case study will consider the Moodle VLE which was chosen for its widespread use.

Predictive elastic replication for multi-tenant databases in the cloud: Predictive elastic replication for multi-tenant databases in the cloud

Cloud computing is a trend of technology aimed at providing on‐demand services with payment based on usage. In order to improve the use of resources, cloud providers adopt multi‐tenant approaches, reducing the operation cost of services. Moreover, tenants have irregular workload patterns, which impacts in guarantees of quality of service, mainly due to interference among tenants. This paper proposes PredRep, a predictive approach to characterize the cloud database system workload and automatically provide or reduce resources by replication techniques. In order to evaluate PredRep, some experiments that measure the quality of service and elasticity are presented. Our experiment results confirm that PredRep reduces cost and SLA violations.

An architecture proposal for musical applications and services on computational clouds

Nowadays cloud computing continues its consolidation, both for technologies virtualization as for platforms development and application availability. These environments are naturally distributed and constituted by many types of software and hardware features, serving a broad range of customers with different requirements. A type of service that has had its use increasingly demanded is the processing of multimedia applications, such as audio and video. This type of service is characterized by different QoS, network and devices requirements, which fits well to cloud computing environments. Many applications or music service providers are available, both for web applications and mobile devices, such as Spotify, Deezer and Last.fm. Non-exclusive applications for music, but also videos, like YouTube and Netflix, are also widely employed by users of multimedia services. This paper describes and discusses an architecture for the implementation and development of computer music services in a cloud computing environment.

StoryMotion: A collaborative recommendation tool for storytelling through photos

In this paper, we present a proposal of a recommendation tool for creating collaborative image stories called Story-Motion. This system will allow users to put their images and photos together in a single story, performed in a semiautomatic way. Any users are free to continue the story as they want, though they can not change what has already been put into it. By doing so, StoryMotion gives its users freedom on the creation process at the same time as it guarantees the authorship of each participant in the story. This can lead to stories that comprehend scopes such as Education, Tourism and Politics. Throughout this paper, it will be described our motivations and theoretical foundation that led to projecting StoryMotion, how our prototype works, its major components and experimental evaluation. After presenting a brief overview of related works, we discuss about our research findings and future work.