UCAmI 2012 - An Infrastructure to Provide Context-Aware Information and Services to Mobile Users

Infrastructure to Provide Context-Aware… 1/26

DeustoTech - Deusto Institute of Technology, University of Deusto

http://www.morelab.deusto.eshttp://www.morelab.deusto.eshttp://www.morelab.deusto.eshttp://www.morelab.deusto.es

December 4, 2012

An Infrastructure to Provide Context-Aware

Information and Services to Mobile Users

UCAmI 2012

Pablo Curiel, Ana B. Lago


Outline

Introduction

The Infrastructure

Implementation

Evaluation

Conclusion


Introduction

Introduction

The Infrastructure

Implementation

Evaluation

Conclusion


Mobile devices’ ecosystem

► Mobile devices play a prominent role in our lives.

► 6 cellular subscriptions for every 7 people in the world.

► Emergence of the Smartphones

► Powerful hardware

► Permanent connectivity

► Equipped with numerous sensors

► Ability to execute a great diversity of applications

► Provide richer and better context information than ever

before

Introduction


The Objective

► Build an infrastructure which

► Manages the context information in mobile environments

► Makes it available for the rest of the entities in the

environment

► Enable

► The provision of relevant information and services to end-

users.

► Mobile application and services to adapt their behaviour to

meet user needs.

Introduction


The Infrastructure

Introduction

The Infrastructure

Implementation

Evaluation

Conclusion


Infrastructure

► The context management infrastructure…

Infrastructure

Co

nte

xt

Pro

vid

ers Co

ntext

Co

nsu

mers

Context Manager

Context Broker

CurrentContext

QueryManager

SubscriptionManager

ContextHistory


► Entities which provide context information to

the system

► Physical sensors, end-user mobile devices,

social networks, mobile services, etc.

Providers

Infrastructure

Co

nte

xt

Pro

vid

ers


► Entities that make use of context information

to adapt their behaviour or to take decisions

► Mobile application and services

Consumers

Infrastructure

Co

ntext

Co

nsu

mers


► Central element

► Context repository

► Stores the context information

retrieved from the sources

► Allows consumers to access it

► Data-centric approach

► Comprised of various independent

components

The Context Manager

Infrastructure

Context Manager

Context Broker

CurrentContext

QueryManager

SubscriptionManager

ContextHistory


► Current Context

► Stores the context information which is valid in

each moment

► Follows the ontological model shared by the

whole system.

► Context History

► Keeps track of the changes taken place in the

context information

► Storage policies

CurrentContext

ContextHistory

The Context Manager

Infrastructure


Context Broker

QueryManager

SubscriptionManager

The Context Manager

Infrastructure

► Context Broker.

► Manages access to current and

history context repositories.

► Receives context information from

the sources and stores it in the

current context

► Moves outdated information to the

context history

► Responds consumers’ requests

querying these two repositories


► Context Broker.

► Two subcomponents

► Query Manager

► Synchronous access

► Subscription Manager

► Asynchronous access

► Register subscriptions and receive notifications

QueryManager

SubscriptionManager

The Context Manager

Infrastructure


Context Manager API

► Unique entry point to the Context Manager functionality

► Exposes methods that enable context source and

consumers to work with context information

► Query the context repositories

► Subscribe to context information changes

► Add/Remove context information

Infrastructure


Implementation

Introduction

The Infrastructure

Implementation

Evaluation

Conclusion


Implementation

► Java

► OSGi

► Jena2 and Jenabean

► RESTful API

Implementation


Evaluation

Introduction

The Infrastructure

Implementation

Evaluation

Conclusion


Starting scenario

► Suggest plans to friends depending on their location and

availability.

Evaluation

► Android end-user app ► Contextual service


Tests design

► And starting from this scenario...

► Tests where

► The contextual service acts as context source, periodically

(every 5s) adding alerts for the end-user application

► The end-user application

►Queries periodically (every 1s) for these alerts

►Registers asynchronous subscriptions to receive them

► In each of these tests the number of context source and

consumers interacting with the context manager varies

Evaluation


Tests results

► Effect of different number of concurrent sources

Evaluation


Tests results

► Effect of different instance count in the current context

Evaluation


Tests results

► Effect of different number of concurrent consumers

Evaluation


Tests results

► Comparison between using Jena and Jena+Jenabean

Evaluation


Conclusion

Introduction

The Infrastructure

Implementation

Evaluation

Conclusion


Conclusions

► The implemented prototype and the tests carried out

have shown

► A functional system which complies with the defined

requirements

► Is extensible

► However, performance issues were observed

► The number of concurrent sources increases

► The context space held by the context manager grows

Conclusion


Future Work

► Removing or replacing Jenabean

► Privacy and security policies

► Trust in context providers

► Control access for context consumers

Conclusion


DeustoTech - Deusto Institute of Technology, University of Deusto

http://www.morelab.deusto.eshttp://www.morelab.deusto.eshttp://www.morelab.deusto.eshttp://www.morelab.deusto.es

An Infrastructure to Provide Context-Aware

Information and Services to Mobile Users

Pablo Curiel

{[email protected]}