【作者】 满自斌；

【导师】 王继曾；

【作者基本信息】 兰州理工大学 ， 计算机应用技术， 2007， 硕士

【摘要】 随着Internet的发展，移动Agent作为Internet和移动计算应用与发展的催生物得到越来越多的人的关注。简单地说，移动Agent是一个独立的计算机程序，可以在异构网络上自主地从一个节点移动到另一个节点，寻找合适的资源，利用与这些资源处于同一主机或网络的优势，就近处理或使用这些资源，代表用户完成特定的任务。与传统的RPC等方法相比具有节省网络宽带，克服网络延迟以及支持离线计算等优点。移动Agent的这些独特的技术优势，使其在近十几年内得到了迅速的发展并且被广泛应用于电子商务、个人助理、安全代理、分布式信息检索、工作流等许多方面。通信是移动Agent中的不可缺少的一个关键部分，无论是移动Agent之间的合作，还是对移动Agent的控制，都离不开通信，因此，必须有一个可靠的通信机制来保证Agent间有效的通信。但是，由于移动Agent的移动性和自主性，在移动Agent间的通信过程中，往往存在通信失效和消息追逐现象，使得移动Agent的通信机制在很大程度上区别于一般意义上的通信。通信失效是指当消息被发送到某一网络节点时接收者已经离开该节点，从而无法接收到该消息，这是由于通信主体的物理位置发生变化而造成的通信不正常现象。消息追逐是在Agent移动非常快的情况下，消息可能追随目标Agent在网络各节点间游荡却永远无法到达而产生的现象。通信失效和消息追逐现象都是移动Agent通信中普遍存在的问题并且与网络和节点故障无关，是纯粹由移动Agent的移动特点造成的。它们使得协作中的Agent不能及时得到协同信息，从而导致协作的失败甚至整个系统的崩溃，是移动Agent系统的致命缺陷。近年来，研究人员已经提出了许多移动Agent通信机制来解决以上的这些问题，然而每一种方法都有其假定条件、设计目的等，因此还没有一个好的通信算法来彻底解决这些现象。鉴于以上问题，本文引入了一种信息表的机制，它提出了一种新的基于信息表的移动Agent通信机制来解决通信中存在的这些问题。更多还原

【Abstract】 With the development of Internet, mobile agent, which is come from Internet and mobile computing application, has more concern by people. In brief, it is an independent computer program, which can transport itself from a node to another independently in a Heterogeneous network. It looks for suitable resources and utilizes the advantage of in the same host or network with these resources, and deals with or uses these resources nearby, finish the specific task on behalf of users. Compared with methods, such as traditional RPC etc., it has the advantage of save the broadband of the network, decrease delay and support calculating off-line etc.These unique technological advantages of Mobile Agent make it get fast development in ten years and it is widely used in a lot of aspect such as e-commerce, personal assistant, security proxy, distributed information retrieval, work flow, etc.Communication plays an indispensable key part in mobile agent. In several of situations, MA at different hosts or nodes of network must cooperate with one another by sharing information and making decision collectively. So, a reliable communication mechanism must guarantee effective communication among agent. But, because of mobility and autonomy of mobile agent, the communication mechanism of mobile agent is different from communication among the general agent. In the process of communication among mobile agent, there commonly exist communication failure and message chasing. So it is need to set up a good communication mechanism among mobile agent. In the communication mechanism, the key is to solve the two problems.Communication failure (CF) is defined as the recipient has already left the node when message is sent to a certain network node, thus the recipient can’t receive this message. Abnormal phenomenon of this kind of communication is caused by the change of the physics position of the communication body.Message chasing (MC) to mean in the situation that agent is migrated very fast, each time when message reaches host, MA has moved in advance to the next host, message may be followed target agent go around but can’t be reached forever.CF and MC problems are general existing problems in MA communication. This is unrelated with the network and failure of node, but caused by the mobile characteristic of mobile agent completely. They make cooperating agents unable to receive the coordinate message in time, thus cause the failure in cooperating or even system break down. This is the critical defect of mobile agent system.In recent years, researchers have already proposed a lot of MA communication mechanism solving above-mentioned problems. However, every kind of method has its own assuming, the purpose of design, and method. So, up till now, there is no unified or structured communication mechanism to solve the MA communication problem better.To the above problems, this paper introduces the technology of the information table in the mobile agent communication mechanism. It set up a kind of new-type MA communication mechanism based on technology of the information table. This will solve CF and MC phenomenon in a great extent that can’t be solved in current communication mechanism.更多还原