云计算环境中SaaS的接入控制和调度策略研究

SaaS是一种基于网络的软件应用模式，是服务提供商将应用软件统一部署在自己的服务器上，用户根据自己的实际需要，通过互联网向服务提供商订购并支付自己所需的服务。在未来，SaaS模式是占主导地位的云服务模型。文中阐述SaaS的基本概念，介绍了SaaS的参考结构以及服务流程，分析概括了不同类型的服务要求的接人控制策略，总结了不同性能要求作业的调度策略，最后结合已有的云计算环境下的SaaS接入控制和调度策略研究成果，展望了未来的研究方向和亟待解决的关键问题。

Survey of Admission Control and Scheduling Mechanisms for Software-as-a-Service in Cloud Computing Environments

SaaS is a kind of network-based software application paradigm that service providers deploy their application software on their servers. Users order and pay for their actual services via the intemet. In the future, the SaaS model will be the dominant cloud service model. It introduces the concept of SaaS, its architecture and its service processes, and analyzes the types of admission control and sched- uling algorithms for different service and performance requirements. It also presents a summary of the current state-of-the-art of the ad- mission control and scheduling algorithms for SaaS in cloud computing environments, a discussion on the future work and some crucial problems should be solved pressingly.