【作者】 戚伟业；

【导师】 刘弘；

【作者基本信息】 山东师范大学 ， 计算机软件与理论， 2008， 硕士

【摘要】 随着Internet的普及和全球化程度的提高,为降低产品的开发成本和提高开发效率,产品设计正由传统的串行工作向支持并行工作转变,从孤立模式向协同模式转变。计算机支持的协同工作(CSCW)已经成为缩减设计成本和提高设计效率的最重要的产品设计模型。CSCW的核心技术是并发控制,而如何保持共享对象的一致性是并发控制首先要解决的问题。只有解决了共享对象的一致性问题,才能在此基础上实现真正的实时协同工作。本文首先对CSCW的产生与发展作了介绍,然后在分析CSCW特性的基础上提出了CSCW的定义。最后对CSCW研究的主要问题和应用领域进行了介绍。接着本文对计算机支持的协同工作系统的特性做了深入的分析,找出影响协同工作系统性能的主要因素,并在此基础上提出协同工作系统中保持共享对象一致性模型的要求。然后分析了协同工作系统为了满足保持共享对象一致性模型的要求需要解决的问题。在以上研究的基础上提出了协同系统中通常的保持共享对象一致性模型。对基于锁机制保持共享对象的一致性、基于令牌环机制保持共享对象的一致性和基于操作序列化机制保持共享对象的一致性进行了研究。讨论了它们的运行机制以及在使用过程中出现的一些问题,在此基础上对三种机制的优缺点做了总结。对操作转换机制进行了深入的研究,对其中的核心运行机制做了详细的论述。先对操作转换方法中确保收敛性的机制做了介绍。然后在介绍协同文本编辑系统中的一些符号和概念的基础上,设计了操作转换函数。在研究和分析协同文本编辑系统中并发控制特点的基础上提出了操作转换控制算法。最后用一个操作转换方法的应用实例验证了操作转换方法在保持一致性模型各种属性上的正确性。对多版本机制进行了深入的研究,并对其中的核心运行机制做了详细的论述。在介绍协同图形编辑系统中的一些符号和概念的基础上,提出了多版本方法中操作效果的结合规则。然后在研究和分析协同图形编辑系统并发控制特点的基础上提出了多对象版本增量创建算法,并用多版本方法应用实例验证了多版本方法在保持一致性模型各种属性上的正确性。最后对多版本方法中的对象标志符机制做了介绍。在研究各种保持共享对象一致性方法的基础上,本文提出了RBCD (Role-Based Collaborative Design)系统,它是本文的主要研究和创新成果。本文详细介绍了RBCD系统中的角色机制,其中包括RBCD系统中的角色划分与权限分配以及RBCD系统中的角色与权限管理。然后在分析传统迟加入方法优缺点的基础上提出了透明迟加入机制。最后对本文的消息驱动机制、基于消息回显的同步机制、冲突检测与消解机制和消息接收与处理机制进行了介绍,并在研究的基础上提出了保持共享对象一致性的分布式算法。最后用一个RBCD系统的设计实例验证了RBCD系统在保持共享对象一致性方面的正确性。更多还原

【Abstract】 With the speedy development of Internets and the improvement of global degree, the products design of global enterprises changes from traditional serial design to parallel design and from isolated pattern to collaborative pattern for cutting short the development cost and improving development efficiency. Computer Supported Cooperative Work has become a kind of important products design model which can cut short the design cost and improve design efficiency.Concurrency control is the kernel technology of CSCW, how to maintain consistency of shared object is the key problem in concurrency control. The resolution of the problem on consistency maintenance of shared object is the basis of implementing Real-time Cooperative Work.First, this article introduces the appearance and development of CSCW,then brings forward the definition of CSCW after analyzing the characteristic of CSCW.Following this article introduces central research problems and application fields of CSCW.Then this article analyzes the characteristic of CSCW systems and finds out the main factors which affect system performance,based on these we bring forward the requirement of maintaining the consistency of shared object. Then this article analyzes the existent problems which consistency maintenance model need to resolve. Based on the above research this article puts forward the general consistency maintenance model.This article makes research on lock-based method,Token-Ring-based method and operation-serial-based method,and introduces the running-mechanism and some issues in application course. Based on the above research this article summarizes the strongpoints and disadvantages of these three methods.This article makes deep research on operation-transform-based method,and discusses the key technology in detail.First it introduces the convergence-maintaining-mechanism in operation-transform-based method.Then we design the operation-transform function after analyzing symbols and conceptions of Collaborative Text Editor system.Based on research and analysis we bring forward the GOT algorithm.In the end we use one instance of operation- transform-based method validates the exactness of maintaining the attributes of consistency model.This article makes deep research on multi-version-based method,and discusses the kernel technology in detail. Then we bring forward the combine-rule of operations effect after analyzing symbols and conceptions of Collaborative Graphic Editor system.Based on research and analysis we bring forward the MOVIC algorithm. Then we use one instance of multi-version-based method validates the exactness of maintaining the attributes of consistency model. In the end we introduces the object-identifier-mechanism in multi-version-based method.Based on the above research on the multi-method which can maintain the consistency of shared object, this article puts forward a RBCD(Role-Based Collaborative Design) system which is the main research and innovation fruits. This article discusses the role mechanism in detail, including role-partition and persession-assign of RBCD system and the management about role and permission of RBCD system. Based on the analysis of traditional latecomer-joining mechanism,we bring forword transparent latecomer-joining mechanism.In the end we introduces message-drivering-mechanism,message-redisplay-based synchronization mechanism,collision detection and resolve mechanism.Based on above research we bring forword the maintenance of consistency on shared object algorithm.In the end we give one applied instance which validates the exactness of maintenance of consistency on shared object.更多还原