An Adaptable Context Management Framework for Pervasive Computing

An Adaptable Context Management Framework for Pervasive Computing

Jared Zebedee (Queen’s University, Canada), Patrick Martin (Queen’s University, Canada), Kirk Wilson (CA Inc, USA) and Wendy Powley (Queen’s University, Canada)
DOI: 10.4018/978-1-60566-290-9.ch005
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Pervasive computing presents an exciting realm where intelligent devices interact within the background of our environments to create a more intuitive experience for their human users. Context-awareness is a key requirement in a pervasive environment because it enables an application to adapt to the current situation. Context-awareness is best facilitated by a context management system that supports the automatic discovery, retrieval and exchange of context information by devices. Such a system must perform its functions in a pervasive computing environment that involves heterogeneous mobile devices which may experience intermittent connectivity and resource and power constraints. The objective of the chapter is to describe a robust and adaptable context management system. We achieve an adaptable context management system by adopting the autonomic computing paradigm, which supports systems that are aware of their surroundings and that can automatically react to changes in them. A robust context management system is achieved with an implementation based on widely accepted standards, specifically Web services and the Web Services Distributed Management (WSDM) standard.
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The notion of pervasive, or ubiquitous, computing goes back to the seminal writings of Weiser (1991). He defines it to be a state where computing devices are so pervasive and critical to our activities that they are taken for granted and effectively disappear into the background. Recent progress in several areas, including the development of smaller and more powerful computing and communication devices, the connectivity in both wired and wireless networks and the emergence of accepted standards for data transfer and presentation (for example HTTP, XML and WAP), are bringing the vision of pervasive computing closer to reality.

Context-awareness is one of the cornerstones of the pervasive computing paradigm. A context-awareness framework provides mechanisms to support context-aware applications. Satyanarayanan (2001) points out that a context-awareness framework must address a number of issues:

  • How is context represented and stored?

  • How is the stored context accessed?

  • What are the minimum services needed to make context-awareness feasible?

  • How is context acquired? Context may be part of a user’s personal computing space or may have to be sensed in real-time from the environment.

  • What are the relative merits of different location-sensing technologies?

A number of frameworks to support the development of context-aware applications have been proposed. The Context Toolkit (Dey, Abowd & Salber, 1999) consists of context widgets and a distributed infrastructure to host the widgets. Context widgets encapsulate context information and hide the details of context sensing. The infrastructure includes services to store, share and protect context. SOCAM (Gu, Pung & Zhang, 2005) is a service-oriented middleware to support context-aware applications. It is based on Web services and provides services for service discovery and context storage, provision and interpretation. The Java Context Awareness Framework (JCAF) (Bardram, 2005) is a service-oriented infrastructure that provided context acquisition, management and distribution through a network of cooperating context services. Context services are Java entities that provide a well-defined API.

A context management system addresses the first two issues raised by Satyanarayanan. It supports the discovery and understanding of local services, devices and environmental constraints (daCosta, Yamin & Geyer, 2008). It is typically made up of a context model and a context manager middleware that implements the model. The context model provides the overall structure of the framework, and specifies how interactions take place between devices. The context manager middleware is the software that implements the interaction specified by the model.

Strang and Linnhoff-Popien (2004) present a survey of context models. They identify several main types of models:

  • Key-value models represent context values as (variable, value) pairs and are frequently used in distributed services frameworks.

  • Markup scheme models integrate the model schema and values using markup languages such as XML (Bray, Paoli, Sperberg-McQueen, Maler, & Yergeau, 2006).

  • Graphical models have been derived from generic modeling methods such as UML and ORM.

  • Object-oriented models exploit the encapsulation and reusability present in an object-oriented approach. The details of context processing are encapsulated at the object level and access to context information is only through specified interfaces.

  • Logic-based models formulate the context as a set of facts, expressions and rules.

  • Ontology-based models provide a uniform way of specifying a model’s core concepts as well as an arbitrary amount of subconcepts and facts, which facilitates sharing and reuse of contextual knowledge.

Complete Chapter List

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Editorial Advisory Board
Table of Contents
Thomas Strang
Theo Kanter
Dragan Stojanovic
Dragan Stojanovic
Chapter 1
Davy Preuveneers, Koen Victor, Yves Vanrompay, Peter Rigole, Manuele Kirsch Pinheiro
In recent years, many researchers have studied context-awareness to support non-intrusive adaptability of context-aware applications. Context-aware... Sample PDF
Context-Aware Adaptation in an Ecology of Applications
Chapter 2
Tarak Chaari, Mohamed Zouari, Frédérique Laforest
Pervasive information systems aim to make information available anywhere and at anytime. These systems should be used in different contexts... Sample PDF
Ontology Based Context-Aware Adaptation Approach
Chapter 3
Florian Daniel
Adaptivity (the runtime adaptation to user profile data) and context-awareness (the runtime adaptation to generic context data) have been gaining... Sample PDF
Context-Aware Applications for the Web: A Model-Driven Development Approach
Chapter 4
I. Roussaki, M. Strimpakou, C. Pils, N. Kalatzis, N. Liampotis
In ubiquitous computing environments, context management systems are expected to administrate large volumes of spatial and non-spatial information... Sample PDF
Distributed Context Management in Support of Multiple Remote Users
Chapter 5
Jared Zebedee, Patrick Martin, Kirk Wilson, Wendy Powley
Pervasive computing presents an exciting realm where intelligent devices interact within the background of our environments to create a more... Sample PDF
An Adaptable Context Management Framework for Pervasive Computing
Chapter 6
Yuanping Li, Ling Feng, Lizhu Zhou
Context is an essential element in mobile and ubiquitous computing. Users’ information needs can be better understood and supplied by means of... Sample PDF
Context-Aware Database Querying: Recent Progress and Challenges
Chapter 7
Carsten Jacob, Heiko Pfeffer, Stephan Steglich
The idea of context-aware services has been around for a long time. The rise of user mobility enabled by well-equipped mobile devices, increasing... Sample PDF
Employing Context Information and Semantics to Advance Responsiveness in Service Composition
Chapter 8
Heinz-Josef Eikerling, Pietro Mazzoleni
The authors present a holistic approach for the efficient design, implementation, and validation of context-aware mobile services. The according... Sample PDF
A Methodology for the Design, Development and Validation of Adaptive and Context-Aware Mobile Services
Chapter 9
Stefan Dietze, Alessio Gugliotta, John Domingue
Context-awareness is highly desired, particularly in highly dynamic mobile environments. Semantic Web Services (SWS) address context-adaptation by... Sample PDF
Bridging the Gap between Mobile Application Contexts and Semantic Web Resources
Chapter 10
Claudia Raibulet
Due to its nature, a mobile-enabled environment is very dynamic: reachable resources and services change very often. Users hardly know which... Sample PDF
Adaptive Resource and Service Management in a Mobile-Enabled Environment
Chapter 11
Nahuel Lofeudo, Andrés Fortier, Gustavo Rossi
Mobile context-aware applications have specific needs regarding data communications and position sensing, that current standard hardware is still... Sample PDF
Kindergarten: A Novel Communication Mechanism for Mobile Context-Aware Applications
Chapter 12
Laurent Gomez, Annett Laube, Alessandro Sorniotti
Access control is the process of granting permissions in accordance to an authorization policy. Mobile and ubiquitous environments challenge... Sample PDF
Access Control in Mobile and Ubiquitous Environments
Chapter 13
Amr Ali Eldin, Semir Daskapan, Jan van den Berg
With the growing interest in context-aware services, attention has been given to privacy and trust issues. Context-aware privacy architectures are... Sample PDF
Privacy Automation in Context-Aware Services
Chapter 14
Adrien Joly, Pierre Maret, Fabien Bataille
These times, when the amount of information exponentially grows on the Internet, when most people can be connected at all times with powerful... Sample PDF
Leveraging Semantic Technologies towards Social Ambient Intelligence
Chapter 15
Federica Paganelli, Dino Giuli
The delivery of real-time, context-aware, and personalized information to end-users for mobility support is a high-priority objective in improving... Sample PDF
An Evaluation of Context-Aware Infomobility Systems
Chapter 16
Nikos Tsianos, Panagiotis Germanakos, Zacharias Lekkas, Constantinos Mourlas
The notion of context in context-aware applications is not merely an issue of external situational circumstances or device/channel properties, but... Sample PDF
Incorporating Human Factors in the Development of Context-Aware Personalized Applications: The Next Generation of Intelligent User Interfaces
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