摘要
迁移工作流是基于移动计算范型提出的工作流管理研究的新方向。工作流业务过程根据业务目标的复杂程度被映射为一个或多个迁移实例(MI),迁移实例是工作流的执行主体,每个迁移实例执行一个目标相对独立的子业务过程,它可以在某个工作位置上利用本地资源和服务执行一项或多项任务。多个迁移实例在停靠站服务器的支持下通过迁移和协作实现总的业务目标。如果当前工作位置不再满足其执行任务的要求,迁移实例可以携带任务说明书和当前执行结果迁移到另一个能满足其要求的工作位置上继续执行。
本文根据迁移工作流的概念模型和迁移工作流系统参考框架,提出了实现迁移工作流系统的一种可行性系统框架,并据此实现了一种可扩展、可定制和可重配置的协同产品商务系统。此系统由迁移实例,停靠站服务器,工作机网络以及应用需求定制客户端几部分构成,采用了微内核模式体系和组件技术思想,用户可以根据需求将以上四部分部署在相同或不同的服务器上,可以在不影响原有应用程序的运行前提下,在系统运行期间添加、删除或替换服务组件,适应环境和工作流应用本身的变化,用户可以根据需要,动态调整服务的组织模式,适应应用需求的动态变化。
由于迁移实例的迁移导致位置不定以及网络条件的多变给迁移实例的通信带来了难题,由此本文提出了一种新的迁移实例间的消息通信机制。该通信机制简化了寻址步骤,解决了邮件的失效处理以保证了邮件的可靠,而且通信阶段不再限制MI的自主移动。同时其支持MI邮件的保序,并基于邮箱分离策略,实现了MI迁移状态邮件的异步处理,而且在对邮件进行正确性及完整性验证的基础上支持错误邮件的重新传送。
本文最后针对迁移工作流系统的四部分给出了实现方案,对系统结构作了相应的改进与创新,在总体上给予迁移工作流系统流程一个详细的规划,使系统各部分结构可以相互协调合作。
The migrating workflow, which is proposed based on the mobile computing model, is a new direction within the workflow management research. In light of the complexity of the business process goal, the workflow is mapped to one or more migrating instances (MI), which are the main execution bodies. Each migrating instance is corresponding to a single business sub-process and can complete one or more tasks with local services and resources in one workplace. Multi migrating instances complete the whole business goal by migrating and cooperation with the support of anchorage server. If the current workplace can' t afford the further task execution, migrating instance will migrate to the next workplace for continuous execution with the task specification and previous execution results.
This paper presents an extendable, customizable and reconfigurable cooperation product commerce system based on the conception of migrating workflow service according to the conception model of migrating workflow and the referrence frame of migrating workflow system. The system is made up of four parts. They are migrating instance, anchorage server, working machine network and application requirement framing for client. The system adopts microkernel pattern architecture and component technology. The user can deploy the four part on the same or different servers according to the demand and can append, delete or replace the service components as the time of the system working without affecting the running of the application. And the system suits the change of environment and its own workflow application. The user can dynamically adjust the organization model of the service so as to suit the dynamic change of the application demand. Because of the migrating instrance'migration its place isn't fixed.And the network is also changeful. Those brings a difficulty to the communications between the migrating instrances. So this paper presents a new message communications mechanism between the migrating instrances. The communication way can simplify the steps of the address search and solve the annulment problem of mails to keep the accuracy of the mails while MI can move on its own without limiting at the communication stage. It also can keep the sequence of MI mails and basing on the way of the mails' separation the mails can de dealed with at the same time of the moving state of MI. Furthermore, the wrong mails can be delivered again through the verifying for the accuracy and completeness of the mails.
In the end , this paper presents a project for the realization of the four parts to migrating workflow system and makes some amelioration and innovation to the structure of the system. It gives a detailed program to the flow of the migrating workflow system as a whole and makes the system each parts correspond well.
引文
[1]Wooldrige,M.and Jennings,N.R.Inteligent agents:theory and practice.The Knowl edge Engineering Review,10(2),115-152
[2]Ravi S.Sandhu,Edward J.Coyne,Hal L.Feinstein,Charles E.Youman,Role-Based Access Control Models,Computer,v.29 n.2,p.38-47,February 1996
[3]Ferraiolo D,Sandhu R,Gavrila S.A Proposed Standard for Role Based Access Control[J].ACM Transactions on Information and System Security,2001,4(3)
[4]Cichocki,A.;Rusinkiewicz,M.Providing Transactional Properties for Migrating Workflows.Mobile Networks and Applications.9(5):473-480,2004
[5]WFMC.Workflow Management Coalition Workflow Reference Model(WFMC-TC00-1003).Workflow Management Coalition,Brussels,1995
[6]范玉顺.工作流管理技术基础[M],清华大学出版社,2001
[7]WFMC.Workflow Management Coalition Terminology and Glossary (WFMC-TC-1011).Technical Report,Workflow Management Coalition,Brussels,1996
[8]W.M.P.van der Aalst.The Application of Petri Nets to Workflow Management.The Journal of Circuits,Systems and Computers,8(1):21-66,1998
[9]W.M.P.van der Aalst.Woflan:A Petri-net-based Workflow Analyzer.Systems Analysis- Modelling- Simulation,35(3):345-357,1999
[10]http://www.javafox.org
[11]http://blogcsdn.net/james999
[12]史忠植.智能主体及其应用[M].科学出版社,北京,2000
[13]王红.移动Agent关键技术研究[M],中国科学院博士论文,2002
[14]P.Maes."Agents that Reduce Work and Information Overload",in CACM37(7),July 1994
[15]D.Chess,C.Harrison et A.Kershenbaum.Mobile Agents:Are They a Good Idea?.IBM Research Division,5 T.J.Watson Research Center,Yorktown Heights,New York,march 1995
[16]C'edric Foumet,G-eorges Gonthier,Jean-Jacques L'evy,Luc Maranget,and Didier R'emy.A calculus of mobile agents.In LNCS,volume 1119,1996
[17]http://www.omg.org
[18]http://www.fipa.org
[19]R.S.Gray,G.Cybenko,etc.D'Agents:Applications and Performance of a Mobile-Agent System.Software:Practice and Experience,32(6):543-573,2002
[20]Danny B.Lange,Daniel T.Chang.IBM Aglets Workbench White Paper,September 1996
[21]T.Sekiguchi,H.Masuhara,A.Yonezawa.A Simple Extension of Java Language for Controllable Transparent Migration and its Portable Implementation,Coordination Languages and Models,Lecture Notes in Computer Science,Volume 1594,April 1999
[22]J.Baumann,F.Hohl,etc.Mole-Concepts of a Mobile Agent System.Technical Report 1997/15,University of Stuttgart,August 1997
[23]曾广周,党妍。基于移动计算范型的迁移工作流研究。计算机学报,2003,10,26(10).
[24]Tao XP.Research on internet based mobile Agent technology and application[Ph.D.Thesis].Nanjing University,2001(in Chinese with English abstract).
[25]Feng XY,Cao JN,Lu J,Chan H.An efficient mailbox-based algorithm for message delivery in mobile agent system.In:Picco GP,ed..Mobile Agents.LNCS 2240,Springer-Verlag,2001.135-151.
[26]周竞扬,陈韬略,陈道蓄,吕建。一种高效可靠的移动Agent间通信机制。软件学报,2003,14(08)。
[27]Baumann J,Hohl F,StraBer M,Rothermel K.Mole-Concepts of a mobile Agent system.WWW Journal,1998,(Special Issue on Application and Techniques of Web Agents):536-554.
[28]Desbiens J,Lavoie M,Renaud F.Communication and tracking infrastructure of a mobile Agent system.In:Proceedings of the 31 st Annual Hawaii International Conference on System Science,Vol 7.IEEE Computer Society,1998.54-63.
[29]陶先平,冯新宇,李新,张冠群,吕建。Mogent系统的通信机制。软件学报,2000,11(8):1060-1065。
[30]王红,曾广周,林守勋。可移动agent系统位置透明通信的一种实现。计算机学报,2001,4,24(4)。
[31]陈韬略,韩亮,陶先平,吕建。移动Agent系统的一个因果保序通信协议。计算机工程,2005,4,31(7)。
[32]S.Bouchenak,D.Hagimont.Pickling threads state in the Java system,Proceeding of Technology of Object-Oriented Languages and Systems Europe-Europe(TOOLS Europe'2000),Mont Saint Michel / Saint Malo,France.June 2000
[33]zhu W.Z.,Wang C.L.,Lau F.:JESSICA2:A Distributed Java Virtual Machine with Transparent Thread Migration Support.In IEEE Fourth International Conference on Cluster Computing,Chicago,USA,September 2002
[34]T.Illmann,F.Kargl,M.Weber,T.Knager.Migration of Mobile Agents in Java:Problems,Classification and Solutions.In Proceedings of MAMA'2000,Wollongong,Australia,2000
[35]E.Truyen,B.Robben,B.Vanhaute,T.Coninx,W.Joosen,P.Verbaeten.Portable Support for Transparent Thread Migration in Java.In ASM:29-43,2000
[36]Ma R.,Wang C.L.,Lau F.M-JavaMPI:A Java-MPI Binding with Process Migration support.In The IEEE/ACM International Symposium on Cluster Computing and the Grid,Berlin,Germany,2002
[37]A.Acharya,M.Ranganathan,J.Salz.Sumatra:A Language for Resource-aware Mobile Programs.Mobile Object System:Towards the Programmable Internet,Lecture Notes in Computer Science,Number 1222,April 1997
[38]T.Suezawa.Persistent Execution State of a Java Virtual Machine,Proceedings of the ACM 2000 Java Grande Conference,San Francisco,California,USA,June 2000
[39]S.Bouchenak,D.Hagimont.Zero overhead java thread migration.Technical Report 0261, INRIA, 2002
[40] Foundation for Intelligent Physical Agents, FIPA Communicative Act Library Specification. Geneva, Switzerland, 3-28,2002
[41] Giacomo Cabri, Letizia Leonardi, Franco Zambonelli, Mobile-Agent Coordination Models for Internet Applications. IEEE Computer 33(2): 82-89, 2000
[42] A Acharya, M Ranganathan, J Saltz. Sumatra: A language for resource-aware mobile programs. In: J Vitek, C Tschudin eds. Proc of Mobile Object Systems: Towards the Programmable Internet. Berlin: Springer, 1997.111-130
[43] A Iqbal, J Baumann, M Straber. Efficient algorithms to find optimal agent migration strategies. Stuttgart University, Tech Rep: TR-1998-05,1998
[44] B Brewington, R Gray, K Moizumi. Mobile agents in distributed information retrieval. In: M Klusched. Intelligence Information Agent. Berlin: Springer-Verlag,1999.355-395
[45] XPDL2.0, http://www.wfmc.org/standards/XPDL.htm