Using High-Level Petri Nets for Hierarchical Grid Workflows
ABSTRACT An increasingly popular application programming model for Grids is to deploy often-used functionalities as remote services on high-performance hosts, following the principles of a service-oriented architecture. Complex applications are created by using several services and specifying a workflow between them. We discuss how workflows of Grid applications can be described easily as High-Level Petri Nets (HLPN), in order to orchestrate and execute distributed applications on the Grid automatically. In order to simplify the handling of complex and large-scale workflows, we introduce hierarchical Grid workflows, making use of the Petri Net refinement paradigm that allows to represent sub-workflows by single graph elements. We show how a complex application, the Barnes-Hut algorithm for N-Body simulation can be expressed as a hierarchical HLPN, using our platform-independent, XML-based Grid Workflow Description Language (GWorkflowDL). We discuss how the GWorkflowDL can be adapted to current Grid technologies, in particular to Java/RMI and the recent WSRF framework.
[show abstract] [hide abstract]
ABSTRACT: This paper proposes two different models for the scheduling net and the job net based on the idea that the scheduling net is separated from the job net. This method makes models compact and intuitional. In addition, the separation benefits the analysis of the job net and the scheduling net respectively. According to the granularity of parallel applications, the scheduling net is designed to four levels, which is convenient to deploy distributed schedulers in parallel environment and is beneficial to the management of different parallel application granularities. Based on Petri Net with changeable structure, the job net model can change its structure dynamically according to the allocation results or states of jobs. Therefore, the model supports dynamic mergence and division of subtasks and can deal with the abnormity of subtasks. We validate the scheduling net and the job net using09/2010; , ISBN: 978-953-307-108-4
[show abstract] [hide abstract]
ABSTRACT: Workflow management for cross-organizational business processes presents a significant challenge recently. The development and implementation of new methodologies and technologies are imperative to tackle this challenge. The process-view approach provides a promising way to facilitate cross-organizational workflows management, especially when it is combined with powerful workflow modeling methods. With the assumption that workflow modeling methods in cooperative organizations are interoperable, a process-view and timed colored Petri net (TCPN) combined approach is proposed to manage cross-organizational workflows, including the formal definition, the mapping from TCPN workflow models to process-view workflow models in which the aspects of control flow and data flow are considered together, and the collaborative execution mechanisms of cross-organizational workflow instances. A hybrid P2P based decentralized workflow management system (WMS) combined with the process-view approach is proposed and built, which is placed on the top of the open JXTA platform and provides a flexible and scalable architecture for cross-organizational workflows management. At last, the cross-organizational workflows management for the distributed development of a circular saw has been used as a test case for system validation.Advanced Engineering Informatics.