QoS Based on Context-Aware Middleware

in Wireless Sensor Network

Yuan Wenjie

Chen Chao

Chen Mingsong

Outline

Basic Introduction Analysis

Scenarios Challenges

Related Works A Prototype

Why A Conceptual Middleware

Conclusion

Basic introduction

Context-aware system

Family RoomDen

Master Bedroom

Media Center Extender (MCX)

Kid’s Room

Media Center PC

Media Center ExtenderXbox

Longhorn PC

Basic introduction

Context computing context

----network connectivity, bandwidth, nearby resources…

user context

----user’s profile, location, behavior preference…

physical context

----lighting, noise, temperature...

temporal context

----time, delay, duration…

Basic introduction

Context Provider

Abstracting useful contexts from heterogeneous

sources, and convert them to certain representations.

Context interpreter

providing logic reasoning services to process context

information

Context Database

Storing current and past contexts for a particular subdomain. Each domain has one logic co

ntext database.

Necessary parts

Basic introduction

QoS-Quality of Service What is QoS?

Application perspective Network perspective

Outline

Basic Introduction Analysis

Scenarios Challenges

Related Works A Prototype

Why A Conceptual Middleware

Conclusion

Scenarios

Consider following cases for a smart space with various location sensors deployed: Population bursts…

System crashes due to overload?

Or let’s make a little compromise? Multiple services available,

Ultrasonic, RFID, pressure sensor, webcam…

Which one to choose?

Scenarios(2)

Consider following cases for a smart space with various location sensors deployed: Real-time position tracking…

time-sensitive and bandwidth-hungry

Can system performance be smoothed?

User-optimized QoS,

intent-capturing, behavior prediction, …

Can system schedules and initializes services on its own initiative ?

QoS Challenges

Resource Communication ability (bandwidth, buffer,…) Computing ability (processors, memory spaces,…) Energy

Traffic Unbalanced traffic (large set of sources, small

number of sinks) Traffic heterogeneity (different reading rates for

different sensors)

QoS features in context-aware middleware

To address above problems, in middleware layer, our QoS should be: supporting priority resource-aware and energy-aware time-aware user-optimized

Outline

Basic Introduction Analysis

Scenarios Challenges

Related Works A Prototype

Why A Conceptual Middleware

Conclusion

Related Works

Name Middleware Based

Context-Aware

QoS Factors

Description

[ 7] No No Density

Accuracy

Delay

Lifetime

It is just focused on the design phase of the application of WSN.

MidFusion Yes No Density

Lifetime

Fault-tolerant

A middleware architecture that uses Bayesian theory paradigm to support sensor network applications performing information fusion.

MILAN Yes No Lifetime

Energy

Bandwidth

A middleware linking network and applications, which is suited for application adaptation and tackles very well the challenges of QoS requirements.

Related Works

Name Middleware Based

Context-Aware

QoS Factors

Description

ESRT Yes No Energy ESRT is a novel transport solution developed to achieve reliable event detection in WSN with minimum energy expenditure. It brings up the concept of non-end-to-end service.

DMS Yes Yes Accuracy

Delay

The proposed architecture is designed to improve productivity levels of medical practitioners through the use of software agents.

[ 12 ] Yes Yes Accuracy

Delay

The middleware provides an abstraction layer between applications and the underlying network infrastructure and it also keeps the balance between application QoS requirements and the network lifetime.

Outline

Basic Introduction Analysis

Scenarios Challenges

Related Works A Prototype

Why A Conceptual Middleware

Conclusion

QoS in Service-Oriented Context-Aware Middleware

Why? Burst traffic (services, communications…) quality-sensitive applications

(real-time, multimedia…)

How? Application profile Context-awareness

Selected QoS Factors

Data dissemination Protocols, Priority, Traffic

Resource Service, Location, Bandwidth, Active sensor nodes

Energy Energy –efficient

Application behavior patterns Temporal context Service differentiation

A Middleware Prototype

Fig. 1. A Conceptual Context-Aware Based QoS Middleware

Outline

Basic Introduction Analysis

Scenarios Challenges

Related Works A Prototype

Why A Conceptual Middleware

Conclusion

Conclusion

Growing demands of QoS in WSN applications

Context-awareness enables new thrusts in QoS

Relevant researches are still in early stage Our prototype needs further implementation

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That’s all, thanks!

26 Oct 2006