A Distributed Virtual Laboratory Platform Based On Service Composition

Nowadays, Virtual Laboratory Environment is a hot topic in the research field of network computing. Unfortunately, since the drawbacks of the reusability of instruments, personalized customization of experimental process and interoperability between heterogeneous instruments, existing virtual environments cannot meet the needs of users well. The difficulty of integrating distributed resources and the low efficiency in network assets utilization are becoming a bottleneck to the further development of Virtual Laboratory Environment.In recent years, distributed computing technologies have been developing very quickly. Service-oriented cmputing technology provides a new idea and means for solveing the problems mentioned above. Service-oriented architecture provides an abstract mechanism for software entities, and the details of underground technologies are hided by Web services, so service-oriented computing serve as an advanced enabling technology for resources reuse and heterogeneous integration. Based on service-oriented cmputing technology, a distributed virtual laboratory platform is presented based on dynamic service composition in this paper. The research works include:(1) A novel architecture is proposed for web-based virtual laboratory with dynamic service composition technology (VL-DSC). In VL-DSC, All instruments are developed with Web Service components. Experimental process can be customized through business-end programming supporting by simulation middleware and process modeling framework, so service virtualization and personalized customization are implemented.(2) A domain-oriented service composition description language is designed in VL-DSC to describe the relationship between virtual instruments formally. It can describe several simulation process models like sequence, split and condition.(3) Based on domain onotology and parameters semantic mapping technology, a dynamic service composition algorithm is presented based on work flow technology and a state-driven strategy, two operation mechanisms are implemented in this paper.(4) Typical application of VL-DSC is given at last, including service-oriented image processing virtual laboratory platform and network firewall virtual laboratory platform.Compared to existing research works, VL-DSC effectively solved some general problems of dynamic integrate, resources sharing, and job scheduling between heterogeneous virtual devices, and thus VL-DSC provides a good platform for modern distance education.