ACTIVE MOBILE DATABASE-SYSTEMS FOR MOBILE COMPUTING ENVIRONMENTS

In recent years, the rapid advancements of wireless communication tech nology and computer down-sizing technology have enabled users to utili ze computing resources anywhere in the computer network. New applicati ons constructed on the mobile database system are becoming popular. Ho wever, the current database systems do not provide special facilities for specific update operations in a mobile computing environment. More over, due to the lack of a common data handling method and a mutual co mmunication mechanism, varieties in implementations may cause applicat ions to be incompatible with each other. In this paper, we take up the issue of data handling, in a mobile computing environment, and propos e an active mobile database system (AMDS) to solve this issue. First, we review the difficulties of dynamic update of databases in a mobile computing environment, and provide a basic concept of AMDS as a soluti on for these difficulties. In order to construct an AMDS, we focus on asynchronous events such as the appearance and disappearance of a mobi le computer in a wireless communication cell. Then we provide a facili ty to specify the behavior of each system in Event-Condition-Action (E CA) rules in the same way as normal active database systems. Moreover, we show the architecture and the design of our implementation of AMDS . And, finally AMDS can be easily implemented as a common database inf rastructure and work well on heterogeneous systems through indoor expe riments.