component-oriented approaches to context-aware systems – monday 14 june 2004 1 the contextor...

Component-oriented approaches to context-aware systems – Monday 14 June 2004

1

The Contextor Infrastructure

for Context-Aware Computing

Gaëtan Rey, Joëlle Coutaz

Engineering HCI research group

CLIPS IMAG, Grenoble, France


2

I-AM


3

Outline

• Synthesis of the state of the art (architectural aspects)

• The contextor infrastructure


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Synthesis of the state of the art

• No consensual definition for the notion of context

• A clear need for infrastructures that support the development of context-aware computing– Like conventional systems: heterogeneity, distribution,

interoperability, …– Unlike conventional systems: multi-scaling, spontaneity, …


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Architecture

Sensing : numeric observables


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Architecture


Transformation : symbolic observables


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Architecture



Situation and context identification


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Architecture




Context adapter


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Architecture




Context adapter

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/ Sec

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/ T

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Architecture




Context adapter

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His

tory


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Architecture




Context adapter

Priv

acy

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tory

Dis

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Architecture




Context adapter

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acy

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For each layer•Services are self-descriptive (meta-interface + meta-data)•Services are self-configurable •Services are local to global (islands of interaction and existence of servers)•Services support multiple communication mechanisms (publish-subscribe, request-answer)•A uniform computational model (process/data oriented) and architectural style


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Architecture




Context adapter

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acy

/ Sec

urity

/ T

rust

His

tory

Dis

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One style does not fit allA set of interoperable infrastructures


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The contextor infrastructure




Context adapter

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Outline

• Contextor

• Discovery

• Examples


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Contextor Software abstraction

Functional core + typed communication channels

Data In

Meta Data In

Data Out

Meta Data Out

Control Out

Control In


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Functional core• Transformation : Data (Type X) + Meta Data Data (Type Y) + Meta Data

– Meta Data : uncertainty, accuracy, latency …

Transformation

Data In

Meta Data In

Data Out

Meta Data Out

Control Out

Control In


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Functional core• Transformation : Data (Type X) + Meta Data Data (Type Y) + Meta Data

• Control : behavior adaptation– supports reconfigurability

Transformation

Data In

Meta Data In

Data Out

Meta Data Out

Control Out

Control In


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Dynamic Composition of Contextors

Application 1 Application 2Data and Meta Data Flow


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Dynamic Composition of Contextors

Application 1 Application 2Controls Flow

Data and Meta Data Flow


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Life Cycle of a Contextor

Creation, conception of contextor

Not RunningNot SuppliedNot Ready

Not in Activity

State 1


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RunningNot SuppliedNot Ready

Not in Activity

State 2Launching the contextor from

its configuration fileNot RunningNot SuppliedNot Ready

Not in Activity

State 1


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Looking for Source Contextors :

Send request for service on the

network


Not in Activity



Not in Activity

State 1


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Running Supplied

Not ReadyNot in Activity

State 3

Subscribingto

Source Contextors




network


Not in Activity



Not in Activity

State 1


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RunningSuppliedReady

Not in Activity

State 4

Lauching the functional CoreWaiting for Sink clients


Running Supplied


State 3

Subscribingto

Source Contextors



network


Not in Activity



Not in Activity

State 1


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In Activity

State 5

New sink Clientconnection

Last sink Client Disconnection

First sink ClientConnection


Not in Activity

State 4


Running Supplied


State 3

Subscribingto

Source Contextors



network


Not in Activity



Not in Activity

State 1


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Stop Command



In Activity

State 5

New sink Clientconnection

Last sink Client Disconnection

First sink ClientConnection


Not in Activity

State 4


Running Supplied


State 3

Subscribingto

Source Contextors



network


Not in Activity



Not in Activity

State 1


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Outline

• Contextor

• Discovery & Scalability

• Examples


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P2P Network Model

• Both a client and a server– Improves the autonomy of contextors


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P2P Network Model


• Fully Distributed Architecture– Supports the arrival/departure of

contextors


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P2P Network Model



contextors

• Local Discovery– Requests use UDP multicast


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P2P Network Model



contextors

• Local Discovery– Requests use UDP multicast

• Distant Discovery– Hybrid Model (GloSS)

– Use of "repeaters“ (model based on geographical localization)


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Outline

• Contextor

• Discovery

• Examples


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Example 1: Human activities Observatory

A dynamic Web page displays users’ level of activity


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Architecture

Web clientTomcat Web Server

Client Web

User User User

Web Pages

Federation of Contextors


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Ada

pte

rDisplaysUsers

Activities


Architecture

Servlet

Observed User

Local informationContextor

Local Activity

Contextor

Mouse Activity

Contextor

Keyboard Activity

Contextor


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[…]

public class ActivityObservatory extends HttpServlet {

private ActivityAdapter myAdapter;

[…]

public void init(){

myAdapter = new ActivityAdapter();

[…]

}

[…]

public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{

[…]

for (int i=0; i< myAdapter.getDataInConnections("activity"); i++){this.displayInformation( myAdapter.getData("activity",i) );

}

[…]

}

[…]

}


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Example 1: Observatory of Activity

[…]public class ActivityMouseContextor extends ElementaryContextor{

private Process mp = null;private String data = "";[…]public void init(){

[…]mp = Runtime.getRuntime().exec("MouseSensor.exe");[…]

}[…]public void functionalCore() {

[…]data += this.mp.read();[…]this.setDataOutValue(data.getBytes());[…]

}[…]

}


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Example 2 : I-AM

• C. Lachenal et N. Barralon Works

• A software infrastructure that supports the dynamic composition of heterogeneous interaction resources to form a unified space.

• In this space, users can distribute and migrate whole or parts of user interfaces as if they were handled by a unique computer.


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Example 2 : I-AM

• C. Lachenal et N. Barralon Works• 2 types of contextors

– Surfaces Contextors• Indicate the presence of each surface (= display)

• Indicate characteristics (size, …) of each surface


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Example 2 : I-AM


– Surfaces Contextors– Link Contextors

• Encapsulate a physical sensor

• Indicate links (spatial relations) between each surfaces

IRDA transmitter / receiver

USB connectorIRDA manager

PIC Microprocessor


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Example 2 : I-AM


– Surfaces Contextors– Link Contextors

• Encapsulate a physical sensor (currently simulated)

• Indicate links (spatial relations) between each surfaces


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Conclusion

• Role of Contextors– Capture and computes contextual information– Distribution (local and global)


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Conclusion

• Role of Contextors– Capture and computes contextual information – Distribution (local and global)

• Middleware– Distributed– Dynamic– Autonomous


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Perspectives

• Evaluation of architecture– Latency – Scalability– Reconfigurability


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Perspectives


• Implementation of examples– Mobility (connections / disconnections)– Distribution (repeaters)


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Perspectives


• Implementation of examples– Mobility (connections / disconnections)– Distribution (repeaters)

• Contextors Upgrade– History of the data


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The Contextor Infrastructure

for Context-Aware Computing

Gaëtan Rey, Joëlle Coutaz

Engineering HCI research group

CLIPS IMAG, Grenoble, France


49

Data et Meta DataXML and XML Schemas

• Benefits– Portability– Extensibility

• Uses– Initialization using configuration files in XML

(name, group, Data In and Data Out class …)– Communication based on XML messages

component-oriented approaches to context-aware systems – monday 14 june 2004 1 the contextor...

Documents

contextaware systems

notion of context

development of context

componentoriented approaches

symbolic observables

architecture sensing

conventional systems

france slide