In order to effectively control the random tasks submitted and executed in grid workflow,a grid workflow model based on hybrid petri-net is presented. This model is composed of random petri-net,colored petri-net and g...In order to effectively control the random tasks submitted and executed in grid workflow,a grid workflow model based on hybrid petri-net is presented. This model is composed of random petri-net,colored petri-net and general petri-net. Therein random petri-net declares the relationship between the number of grid users' random tasks and the size of service window and computes the server intensity of grid system. Colored petri-net sets different color for places with grid services and provides the valid interfaces for grid resource allocation and task scheduling. The experiment indicated that the model presented in this letter could compute the valve between the number of users' random tasks and the size of grid service window in grid workflow management system.展开更多
The correctness of workflow models is one of the major challenges in context of workflow analysis. The aim of this paper is to provide an improved Petri net-based reduction approach for verifying the correctness of wo...The correctness of workflow models is one of the major challenges in context of workflow analysis. The aim of this paper is to provide an improved Petri net-based reduction approach for verifying the correctness of workflow models. To the end, how to represent well-behaved building blocks and control structures of business processes by Petri nets is given at first, and then how to build well-structured process nets is presented. According to the structural characteristics of well-structured process nets, a set of legacy reduction rules are improved and extended, and then a complete Petri-net-based verification approach is proposed. The sound ness and the complexity with polynomial time for the improved re duction method are also proven.展开更多
针对航班地面保障实际作业流程的精准刻画与性能评估,提出一种多层级航班地面保障随机Petri网(Stochastic Petri Net,SPN)构建及性能分析方法.将保障节点间的衔接过程与保障节点进行过程同时作为随机Petri网的变迁,构建多层级航班地面保...针对航班地面保障实际作业流程的精准刻画与性能评估,提出一种多层级航班地面保障随机Petri网(Stochastic Petri Net,SPN)构建及性能分析方法.将保障节点间的衔接过程与保障节点进行过程同时作为随机Petri网的变迁,构建多层级航班地面保障SPN模型解析保障全流程复杂的串并联关系.采用时间性能等价化简方法降低模型分析的难度,在此基础上建立同构马尔科夫链对模型进行性能分析,得到多层级航班地面保障流程SPN模型的库所繁忙率和变迁利用率.建立的输入输出库所繁忙率四象限图可直观揭示流程中的低效与高效运行区域,实现保障节点及衔接过程前后续状态的精准分类,结合变迁利用率结果,并基于变迁平均发生速率动态变化过程中稳态概率累计变化量识别关键保障节点或衔接,包括4个关键保障节点及6个关键节点间的衔接.研究结果表明:航班地面保障的关键部分多集中在前后衔接不紧密的不同节点间,如餐食及机供品配供完成后等待关客舱门衔接过程,即使单个保障节点的作业时间较短,但若其前续准备或后续完成状态耗时较长,易导致整体保障效率降低;当关键保障节点或衔接平均发生速率超过0.2,即对应持续时间缩短至5 min后,保障流程整体持续时间下降趋于稳定.研究成果可以为机场协同决策下目标撤轮挡时间预测准确性的提高及促进机坪运行保障效率提供理论基础和方法支撑.展开更多
基金the National Natural Science Foundation of China (No.60573141, 70271050)the Natural Science Foundation of Jiangsu Province (No.BK2005146)+3 种基金the High Technology Research Programme of Jiangsu Prov-ince (No.BG2005037, BG2005038, BG2006001)the High Technology Research Programme of Nanjing (No. 2006RZ105)the Foundation of National Laboratory for Modern Communications (No.9140C1101010603)the Key Laboratory of Information Technology Processing of Jiangsu Province (No.kjs05001, kjs0606).
文摘In order to effectively control the random tasks submitted and executed in grid workflow,a grid workflow model based on hybrid petri-net is presented. This model is composed of random petri-net,colored petri-net and general petri-net. Therein random petri-net declares the relationship between the number of grid users' random tasks and the size of service window and computes the server intensity of grid system. Colored petri-net sets different color for places with grid services and provides the valid interfaces for grid resource allocation and task scheduling. The experiment indicated that the model presented in this letter could compute the valve between the number of users' random tasks and the size of grid service window in grid workflow management system.
基金Supported by the Scientific Research Foundation of Edu-cation Agency of Liaoning Province (20040088) and Scientific ResearchFoundation of Dalian Nationalities University (20046202)
文摘The correctness of workflow models is one of the major challenges in context of workflow analysis. The aim of this paper is to provide an improved Petri net-based reduction approach for verifying the correctness of workflow models. To the end, how to represent well-behaved building blocks and control structures of business processes by Petri nets is given at first, and then how to build well-structured process nets is presented. According to the structural characteristics of well-structured process nets, a set of legacy reduction rules are improved and extended, and then a complete Petri-net-based verification approach is proposed. The sound ness and the complexity with polynomial time for the improved re duction method are also proven.
文摘针对航班地面保障实际作业流程的精准刻画与性能评估,提出一种多层级航班地面保障随机Petri网(Stochastic Petri Net,SPN)构建及性能分析方法.将保障节点间的衔接过程与保障节点进行过程同时作为随机Petri网的变迁,构建多层级航班地面保障SPN模型解析保障全流程复杂的串并联关系.采用时间性能等价化简方法降低模型分析的难度,在此基础上建立同构马尔科夫链对模型进行性能分析,得到多层级航班地面保障流程SPN模型的库所繁忙率和变迁利用率.建立的输入输出库所繁忙率四象限图可直观揭示流程中的低效与高效运行区域,实现保障节点及衔接过程前后续状态的精准分类,结合变迁利用率结果,并基于变迁平均发生速率动态变化过程中稳态概率累计变化量识别关键保障节点或衔接,包括4个关键保障节点及6个关键节点间的衔接.研究结果表明:航班地面保障的关键部分多集中在前后衔接不紧密的不同节点间,如餐食及机供品配供完成后等待关客舱门衔接过程,即使单个保障节点的作业时间较短,但若其前续准备或后续完成状态耗时较长,易导致整体保障效率降低;当关键保障节点或衔接平均发生速率超过0.2,即对应持续时间缩短至5 min后,保障流程整体持续时间下降趋于稳定.研究成果可以为机场协同决策下目标撤轮挡时间预测准确性的提高及促进机坪运行保障效率提供理论基础和方法支撑.
