10,873 research outputs found
Autonomous resource-aware scheduling of large-scale media workflows
The media processing and distribution industry generally requires considerable resources to be able to execute the various tasks and workflows that constitute their business processes. The latter processes are often tied to critical constraints such as strict deadlines. A key issue herein is how to efficiently use the available computational, storage and network resources to be able to cope with the high work load. Optimizing resource usage is not only vital to scalability, but also to the level of QoS (e.g. responsiveness or prioritization) that can be provided. We designed an autonomous platform for scheduling and workflow-to-resource assignment, taking into account the different requirements and constraints. This paper presents the workflow scheduling algorithms, which consider the state and characteristics of the resources (computational, network and storage). The performance of these algorithms is presented in detail in the context of a European media processing and distribution use-case
Enhancing Workflow with a Semantic Description of Scientific Intent
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Enforcing reputation constraints on business process workflows
The problem of trust in determining the flow of execution of business processes has been in the centre of research interst in the last decade as business processes become a de facto model of Internet-based commerce, particularly with the increasing popularity in Cloud computing. One of the main mea-sures of trust is reputation, where the quality of services as provided to their clients can be used as the main factor in calculating service and service provider reputation values. The work presented here contributes to the solving of this problem by defining a model for the calculation of service reputa-tion levels in a BPEL-based business workflow. These levels of reputation are then used to control the execution of the workflow based on service-level agreement constraints provided by the users of the workflow. The main contribution of the paper is to first present a formal meaning for BPEL processes, which is constrained by reputation requirements from the users, and then we demonstrate that these requirements can be enforced using a reference architecture with a case scenario from the domain of distributed map processing. Finally, the paper discusses the possible threats that can be launched on such an architecture
Modularity for Security-Sensitive Workflows
An established trend in software engineering insists on using components
(sometimes also called services or packages) to encapsulate a set of related
functionalities or data. By defining interfaces specifying what functionalities
they provide or use, components can be combined with others to form more
complex components. In this way, IT systems can be designed by mostly re-using
existing components and developing new ones to provide new functionalities. In
this paper, we introduce a notion of component and a combination mechanism for
an important class of software artifacts, called security-sensitive workflows.
These are business processes in which execution constraints on the tasks are
complemented with authorization constraints (e.g., Separation of Duty) and
authorization policies (constraining which users can execute which tasks). We
show how well-known workflow execution patterns can be simulated by our
combination mechanism and how authorization constraints can also be imposed
across components. Then, we demonstrate the usefulness of our notion of
component by showing (i) the scalability of a technique for the synthesis of
run-time monitors for security-sensitive workflows and (ii) the design of a
plug-in for the re-use of workflows and related run-time monitors inside an
editor for security-sensitive workflows
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