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Dependability evaluation of cloud infrastructures.

Cloud computing is a model that resources such as storage, applications and networking infrastructures can be offered as services over the internet. Cloud applications are becoming ever larger and more complex with high availability requirement. This paper presents a modeling strategy based on a hierarchical and heterogeneous modeling for planning of cloud infrastructures. The modeling strategy allows the selection of cloud infrastructures according to dependability and cost requirements. A case study based on virtual learning environments hosted on Eucalyptus platform is adopted to demonstrate the feasibility of the proposed modeling strategy.

Cloud infrastructure planning considering different redundancy mechanisms

Cloud computing has been established as a remarkable business model that allows the outsourcing of processing, memory, storage, and networking provided by cloud infrastructures. Cloud applications require computing resources being promptly available to serve the on-demand load. If resources are not available to meet user requests, service dependability and performance may be considerably impacted. Thus redundancy mechanisms are a suitable solution for rapidly providing resources to recover the failure in service delivery. However, one of the main difficulties in cloud infrastructures are related to the selection of redundancy mechanisms that can provide a high availability with acceptable costs. This paper provides a methodology, stochastic models and an optimization approach for assisting the planning of private cloud infrastructures, which are selected according to the availability, downtime and cost constraints. Two case studies based on cloud platform are adopted to demonstrate the feasibility of the proposed work.

Towards a model-driven approach for treating quality attributes of service-based business processes

A systematic way for treating non-functional quality attributes into the business process management lifecycle is still a challenge. The agnostic, integrated and automated treatment of these attributes from the most abstract business level to their technical realisation at execution level is a complex task. In this context, this paper presents a model-driven approach centred on quality attributes of business processes. Additionally, two key characteristics of our approach are the agnostic treatment of the quality attribute being considered and its projection on standards such as user requirement notation URN, UML for QoS and WS-Policy. To illustrate the proposed approach, a supply chain management use case is used. Finally, in order to evaluate the model-driven approach, an evaluation plan based on goal/question/metric GQM is defined, providing the rationale to define and to apply evaluation metrics of interest.

Automation of service-based security-aware business processes in the Cloud

The use of business process standards to model and execute business needs is growing rapidly. In addition, Service-oriented Computing has been adopted to realize business processes, which basically consists of executing the process activities using services available in the Internet. In this context, the importance of security is apparent, because sensitive data sent over the Internet may be accessed by unauthorized third-parties. To prevent security problems, users may associate security requirements that must be enforced in essential tasks of the business process. This fact leads to the need of automation, because both functional and security requirements should be modeled, at high-level, and enforced, at execution level. This work proposes a cloud-based solution named BPA-Sec4Cloud that supports all phases of the security-aware business process automation, from its modeling to its deployment. The use of a cloud-based solution facilitates the deployment process because all needed resources are available in the cloud and ready to be used. In addition, the cloud is also used as a platform in order to provide specific services, such as translators, to support the automation process. In order to evaluate the BPA-Sec4Cloud, the solution was compared against existing solutions through the use of metrics related to the quality of generated artifacts.

xLONGWisE: An environment to support the execution of Long Running Workflows

Long Running Workflow (LRW) is a particular kind of workflow that lasts for hours, days, or even weeks to complete its execution. The long duration is directly associated to the nature of certain business processes, such as to get a home mortgage or obtain the money related to a car insurance. LRWs are usually deployed in execution environments specially designed to support their inherent characteristics such as the possibility of changes in the business rules, appropriate treatment of resources provisioning, dynamic reconfiguration and so on. Appropriate treatments for these characteristics imposes a great complexity to execution environment developers. In this context, this paper presents xLONGWisE (extended LONg runninG Workflow Execution environment), a solution specially conceived to support the execution of LRWs that adopts an elaborated mechanism to improve the dynamic reconfiguration aspect. The solution analyzes the execution of the workflow that is in progress, the changes that should be made and, according to the identified scenario, it uses different reconfiguration strategies to apply those changes. In order to evaluate xLONGWisE, an experiment related to the scenario of a real health insurance organization was carried and demonstrated the efficiency of the proposed solution.

Comparative Study of Service-Based Security-Aware Business Processes Automation Tools

The use of business processes to model and design business activities is becoming a reality to a significant number of companies. Meanwhile, the Service-Oriented Architecture (SOA) is being a widely adopted strategy for business processes execution, which often demands communication between different (and remote) services. This fact leads to the need of incorporating security elements into business processes, because sensitive data can be targeted in the communication process. Existing tools currently focus both on the functional automation by translating high-level business processes in executable artifacts and/or on the security automation by translating security requirements into executable security configurations. In this work, we present a comparative study that evaluates these tools using relevant metrics. A solution named BPA-Sec Analyzer was also developed to automatically generate relevant statistics information related to the produced artifacts. An illustrative scenario is introduced to support the comparison/evaluation.