A context model, design tool and architecture for context-aware systems designs

Abstract

The concept of context awareness is widely used in mobile and ubiquitous computing to reduce explicit user input and customization through increased use of implicit input. This requires that the systems take account of context in order to infer the user’s objective and relevant environmental features. In order to develop systems that support the user in an automatic and appropriate manner, a design process which provides understanding about context and its use is required. Further, an implementation architecture is required which benefits from this design process and supports both system implementers in realising the designs and users in refining and, where necessary, correcting the context sensing and modelling processes at run time.

The aim of this dissertation is to introduce a uniform and systematic, by which we mean consistent and structured, context model and design tool to the design and implementation of context-aware systems. The context model helps to bridge the gaps between designers, developers and users to support shared understandings about context, and it presents a structured understanding of what is taken into account as context. The context model presents a design tool that provides systematic steps and instructions for designing the context-aware system to meet user requirements. It guides the designers to make consistent design choices to meet user requirements rather than adopting a more technology-driven approach.

This dissertation provides 3 main contributions. The first contribution is to introduce a systematic context model based on Activity Theory. The context model describes a uniform set of context elements and relationships between them. We explain why Activity Theory is chosen to help model context. The concept of adding a temporal dimension to extend Activity Theory is proposed. Based on our extension to Activity Theory, the second main contribution is to develop a design tool. Our context model and design tool can be used to model and represent context, evaluate the potential of context resources, indicate situations where a context-aware system is feasible to support a user, and guide the designer in providing functions to support a user without taking control away from the user. In order to support the functionalities that our design too introduces to the context aware system, as our third main contribution, we present a three layered architecture. In this dissertation, we provide a demonstration of how design choices can be explored, supporting flexible reuse of well structured and discrete context resources, elements and reasoning process.

The use of the context model, design tool and architecture is demonstrated in different scenarios. First the context model and design tool are applied to a simple conference scenario and an initial scenario based on an ethnographic study of the A&E department in a London hospital. The resulting designs for both scenarios are developed in a context-aware system architecture, where the context model and its associated design process are applied to generate design and implementation recommendations. Finally, a prototype architecture is implemented using Java and XML based on the design for patient check-in and check-out scenarios in the hospital A&E department.

Date of Award	1 Jan 2009
Original language	English
Awarding Institution	University of Bath
Supervisor	Eamonn O'Neill (Supervisor)