Mobile Agent Model for Flexible Distributed Systems.

在传统的客户端-服务器应用程序中，应用程序和对象分别分布在客户端和服务器中。另一方面，每个名为Servant的计算机都是对等的，在对等(P2P)系统中可以有程序和对象。此外，从高性能、高可靠性的计算机(如数据库服务器)到不太可靠的个人计算机和移动台，数量庞大、类型多样的计算机在网络中相互连接。讨论如何在P2P系统中开发和执行可靠的数据库应用程序是至关重要的。在数据库应用程序中，事务操作对象以满足ACID(原子性、一致性、隔离性和持久性)属性。在传统的数据库系统中，对象被锁定或事务被加时间戳以串行化多个事务。如果操作多台计算机中的对象，则必须在两阶段承诺(2PC)Proto…中支持对多台计算机的原子操作在这项研究中，我们讨论了一种新型的智能体模型--事务型智能体模型，用于在具有提交约束类型的多台计算机上操作对象。事务代理被定义为移动代理，它在计算机之间移动，并在一台或多台计算机上本地操作具有承诺约束类型的对象。此外，如果两个代理以冲突的方式操作同一对象，则一个代理与另一个代理协商。通过协商，每个代理自主地决定代理是保留还是释放对象。如果要移动的代理所在的计算机出现故障，事务代理将自动查找另一台目标计算机。在本研究中，我们讨论了如何在Java Aglets和Oracle数据库系统中实现事务代理。给出了基于移动代理的交易系统的应用评价。如果Aglet类是先验加载的，则事务代理可以比传统的客户端-服务器模型更快地操作对象服务器。较少

In traditional client-server applications, application programs and objects are distributed into clients and servers, respectively. On the other hand, every computer named servant is peer which can have programs and objects in peer-to-peer (P2P) systems. In addition, huge number and various types of computers are interconnected in networks, ranging from high-performance, high-reliable computers like database servers to less-reliable personal computers and mobile stations. It is critical to discuss how to develop and execute reliable applications on databases in P2P systems. In database applications, transactions manipulate objects so as to satisfy ACID (atomicity, consistency, isolation, and durability) properties. In traditional database systems, objects are locked or transactions are timestamped to serialize multiple transactions. If objects in multiple computers are manipulated, the atomic manipulation of multiple computers has to be supported in the two-phase commitment (2PC) proto … More col.In this research, we discussed a novel type of agent model, transactional agent model to manipulate objects in multiple computers with types of commitment constraints. A transactional agent is defined to be a mobile agent which moves around computers and locally manipulates objects in one or more than one computer with type of commitment constraint. In addition, an agent negotiates with another agent if the agents manipulate a same object in a conflicting manner. Through the negotiation, each agent autonomously makes a decision on whether the agent holds or releases the objects. A transactional agent autonomously finds another destination computer if a computer where the agent to move is faulty. In this research, we discussed how to implement transactional agents in Java Aglets and Oracle database systems. We showed the evaluation of the mobile agent-based transaction systems for applications. If Aglets classes are a priori loaded, the transactional agents can manipulate object servers more shortly than the traditional client-server model. Less