【作者】 周晓林；

【导师】 曾广周；

【作者基本信息】 山东大学 ， 计算机应用技术， 2007， 硕士

【摘要】 P2P即Peer-to-Peer，通过节点间的直接信息交换来实现计算资源和服务的共享。与传统的C／S模型相比，它在有效利用网络上大量闲置的信息资源、存储空间、处理器周期等资源，避免服务器带来的瓶颈问题以提高系统健壮性，降低服务器成本，提高对网络带宽的利用效率，提高系统的可适应性，提高用户的自主性等方面都有一定的优势。随着现代网络环境的日趋复杂化，信息源、信息传递和信息流控制表现出越来越强的松耦合特点，传统集中式的协作系统的时代即将过去，取而代之的将是分布式的信息处理与应用运行环境，这正是由P2P所代表的技术方向。本文研究的目标为设计一种基于P2P的开放的可扩展的CSCW平台，使其与基于C／S结构的协作平台相比具备更强的健壮性，对协作环境的变化具有更好的适应性，为协作参与者提供更多的自主性，更加充分的利用各节点的资源从而分散负载以提高整体效率，同时具备良好的灵活性和可扩展性。在研究分析目前的比较成熟的P2P平台的基础上，选取SUN公司的JXTA开源项目作为P2P平台环境。JXTA在Internet和非IP网络之上建立虚拟P2P网络，提供支持在任何平台、任何网络、任何地点以及任何时间实现P2P计算的一整套简单、小巧和灵活的机制。通过研究P2P环境下的协作模型，提出了层次化的虚拟工作组模型的概念，即P2P网络中的各节点为了协作完成某个任务而组成的具有任意层次的群组集合，通过此模型可以一致的描述多种类型的协作。参考微内核体系结构模式和构件技术思想，将平台划分为三层：内核，负责服务组件的管理以及各组件之间的功能调用，用户可以通过内核动态添加或移除服务组件，以定制和扩展平台的功能从而适应不同领域的特殊应用；通用服务层，提供一般性的通用协作服务如群组管理、通信、对象持久化等；领域应用服务层，为相应的领域应用提供服务。内核的轻量化以及服务组件间的低耦合使系统具备较高的灵活性和可扩展性。设计并实现了平台的工作流领域应用服务，构建并运行了工作流实例血液病就诊流程。分析工作流实例血液病就诊流程的运行，表明平台的设计达到了课题预定的目标，对协作环境的变化具有良好的适应性，为协作参与者提供了更多的自主性，具备良好的灵活性和可扩展性。更多还原

【Abstract】 P2p (peer to peer), sharing of computer resources and services by direct exchange between nodes. Compared with the traditional mode C/S, it has advantage in making use of the unused information resource, storage space and CPU time on the network, avoiding the bottleneck brought by the server to improve the robustness of system, reduce the cost of the server, enhancing of using efficiency of the network bandwidth, improving of the flexibility of system, improving the user’s autonomy. With the modern network environment more complicated than ever before, information source, information transferring and information flow control are more weak coupling, traditional centralized collaboration system will be the history, the distributed information management and application running environment will replace it. This is also the P2P technology’s direction. The target of this research is to design an open and extendable CSCW platform based on P2P, compared with collaboration platform based on C/S mode, which is more flexible to the change of the collaboration environment, offers the user higher autonomy, makes use of the nodes’ resource more adequately to improve the efficiency of the whole system. And the platform has good flexibility and extendability.The thesis based on investigating and analyzing nowadays P2P platforms, adopts the open source project JXTA of the SUN Co. Co. JXTA create virtual network based on Internet and non-IP network. It provides a simple, tiny and flexible mechanism to implement P2P computing in any platform, any network, anywhere and anytime.Based on research of collaboration mode, the thesis raises the concept layered virtual work group mode, the discretionarily layered group aggregate which is formed by the nodes in P2P network to execute one task. Using this mode, we can describe many kinds of collaboration work.Consulted with the microkernel pattern architecture and component technology, the platform can be decomposed to the layers: the microkernel layer, which is used to manage the components of the system and the communication between them and users can extend the function of the platform to satisfy different domain application by appending or delete component through microkernel; the common service layer, which supply common collaboration service such as group management, communication and object persistency; domain application service layer, which supply service to some domain applications. The lightweight kernel and weak coupling components makes the system more flexible and extendable. The thesis designed and implemented the workflow domain application service, designed and executed the workflow instance medical consultation process of blood illness.The analysis of the execution results of the medical consultation process of blood illness shows that the platform realizes the designation objects. It has good flexibility to the change of the collaboration environment, offers high autonomy to the users, and has good extendability.更多还原