面向移动查询的邮件消息发布算法研究

Mobile Query Oriented Mail Message Passing Algorithm Researching

1引言 移动查询及优化是移动计算和移动数据库领域的主要研究方向之一[7,8],在移动查询计算环境中,用户不再是固定在网络某个位置上,而是具有移动性的节点,除了移动性特点之外,还有网络弱连接性、网络条件多样性和动态性、网络通信的非对称性等.另一方面,用户的移动计算设备具有电源能力、计算、存储能力、人机交互能力的有限性、特殊性和多样性等等[3,12](一个典型的移动计算系统模型参见文[12]的图1).赵宇鹏硕士研究生,主要研究方向为移动查询模型设计与优化;徐明博士,副教授,主要研究方向为移动计算及计算机体系结构.

The Difference between mobile computing environment and static one makes a special mobile query model become necessary . In this paper we introduce a mobile query model based on proxy/mailbox mechanism, and propose a mail message passing algorithm as the essence of the mailbox mechanism for energy-saving query . The communication part of user mobile computer can be in doze mode for energy saving when waiting for a query result. The mailbox proposes every dozing time length by statistics information about query response time distribution, and notifies the user by mail messages. The User End computes actual dozing time length by the proposed value and its own environments, and only begins listening to the data channel after receiving mail-ready message. Through analyzing and simulating, we can make some conclusions as followed. First, this algorithm can decrease ratio between the total active time in a query and the whole response time, so it is very energy saving especially for some long time query cases. Second , his algorithm achieves the advantage by sacrificing some delay, so it is more fit for many mobile query applications that do not care too much about some delay.