Context Sensitive Database Summarisation

Author: Darin Chan

Chan, Darin, 2006 Context Sensitive Database Summarisation, Flinders University, School of Computer Science, Engineering and Mathematics

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The use of databases is a common practice for storing and organising large amounts of data. In a distributed environment, especially widely distributed systems, replication provides a means for storing an entire database locally. However, in an environment where mobile devices are used, resource limitations on both storage and power capacity eliminates the possibility of full replications. Moreover, reliable access to centralised databases is not always possible in these environments. Consequently, there is a need to find ways of storing data on a mobile computer in such a way as to maximise user access while providing answers at an acceptable level of accuracy. This dissertation argues that it is useful to know and incorporate the user context in which the database will be used in the creation process of the mobile database. It investigates a context sensitive summarisation technique and provides a proof of concept prototype, COSMOS, which maximises data availability based on the context in which the system is being used and the accuracy required by the user. More specifically, a framework for summarising data using the context of the user is introduced. Local nulls are proposed to the relational algebra and SQL to allow efficient querying of summary databases. Some modifications to the database management system include the handling of transactions in the system, update propagation and system failure protocols. These modifications are proposed to allow the effective use of the summarised data.

Keywords: Databases,data,mobile devices,accuracy,user context,relational algebra,SQL

Subject: Computer Science thesis

Thesis type: Doctor of Philosophy
Completed: 2006
School: School of Computer Science, Engineering and Mathematics
Supervisor: John Roddick