【作者】 唐臻；

【导师】 李胜利；

【作者基本信息】 华中科技大学 ， 计算机软件与理论， 2009， 硕士

【摘要】 当前各学科的虚拟教学实验系统的开发没有统一的标准,存在实现方法各异,扩展性差的问题。多领域统一建模方法为解决这个问题提供了很好的思路。然而,目前传统的多领域统一建模方法,如Modelica,主要是面向科学计算,实时交互性弱,无法满足虚拟教学实验的要求。同时统一的虚拟实验平台需要支持大量并发用户的访问,传统的多领域建模方法也未予以考虑。基于多领域建模的交互式虚拟实验调度机制解决了多领域统一建模与实时虚拟教学实验的差异性问题。调度机制将仿真任务分解成多段连续时间的计算单元,并周期性的运行仿真任务,从而实现实时计算过程。同时在各计算单元中加入对用户响应的处理,来达到虚拟实验实时交互的目的。在对仿真任务进行调度时,周期性仿真任务步长算法控制每段周期运行的仿真任务的步长值,以达到提高系统吞吐率的目的。交互性仿真任务步长算法通过合理的设置对用户操作进行响应的仿真任务的步长值,以达到减少响应时间的目的。仿真过程中通过仿真频率来控制仿真任务周期性的运行。在实时调度算法中,通过计算出服务利用率来保证调度期间的服务质量。系统测试表明,交互式虚拟实验调度机制能够实现虚拟实验的实时交互性,并且在高负载情况下,整个系统的吞吐率较传统仿真建模方法,提高了30%以上,保证了整个系统的服务质量。更多还原

【Abstract】 Current development system of virtual educational experiment of various disciplines faces with the problems of no uniform standards, heterogeneous developing methods and poor scalability. Multi-domain unified modelling (MDUM) could provide the mentality to solve the above problems, However, at the present ,traditional MDUM (such as Modelica) is mainly targeted at scientific computing and lack of capability for supporting real-time interaction, which could not meet the requirements of virtual educational experiment. Moreover, uniform platform of virtual educational experiment should be capable of sup-porting massive concurrent user access, which is also not taken into consideration in tradi-tional MDUM.The interactive scheduling mechanism of virtual experiment based on Modelica is used to solve the discrepancy between traditional MDUM and real-time virtual educational ex-periment. The scheduling mechanism splits the simulation task into multiple time-continuous computing units, and executes the simulation task periodically in order to achieve real-time computation. Besides, the handling process for user request is integrated into each computing unit to realize the purpose of real-time interaction in virtual experi-ment. Periodic simulation task scheduling algorithm is utilized to control the step of each simulation task in the scheduling, which could improve the throughput of system. Simula-tion step for user response is configured reasonably by interactive simulation task schedul-ing algorithm, which could yield shorter response time. And the scheduling mechanism controls the simulation circle by implementing simulation-frequency. In the real-time scheduling algorithm, the service utilization rate is calculated to guarantee service quality during the scheduling period.System testing demonstrates that the interactive scheduling mechanism could meet the demand of real-time interaction in virtual experiment, and compared to the traditional MDUM, its throughput increased by 30 percent under high loading, which could guarantee service quality for the whole system.更多还原