Component-Based Fault Tolerant Distributed Context Data Management for Context Aware Systems
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Date
2009-10
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Addis Ababa University
Abstract
Context awareness allows applications to adapt themselves to their changing user circumstances or changing computing environment in order to better suit the needs of the user. Context information that supports such adaptations is provided by the underlying context management infrastructure, which gathers, pre-processes, manages and provides context information from a variety of context information sources. The distributed nature of the infrastructure is prone to failures which have a negative impact on the usability of context aware applications. In this thesis, we identified the shortcomings of existing works in relation to fault tolerance in distributed context data management system. The shortcomings are lack of adequate consideration for faults that arise from the distributed software components and lack of full-fledged fault management approach. In order to overcome these limitations, we proposed a fault management architecture that wraps the software pieces in components in order to administer as component architecture. The architecture is composed of the manager system and the managed system. The manager system consists of fault manager component and supplementary modules. Fault manager component is responsible for monitoring components, detecting faulty components and repairing the faulty components. Supplementary modules provide the necessary functionalities to the fault manger to carry out its activities. On the managed system, the core components are context pre-processing component that collects and aggregates context data from potential context data sources like sensors, context storing component that stores context data in a database and context reasoning and decision component that performs ontology-supported context reasoning. To prove the validity of the proposed architecture, we developed a prototype that implements the major components of the proposed architecture. Faults have been introduced manually into the context management system and results obtained from our experiment show that the fault manager allows the system to automatically and transparently recover from the induced failures. Keywords: Context Aware Systems, Fault Tolerance, Component Based Computing, Distributed Context Data Management.
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Keywords
Context Aware Systems; Fault Tolerance; Component Based Computing; Distributed Context Data Management