context-aware service adaptation...

Content and Service Adaptation Management

By

Abdelhak Attou

Supervised by

Prof Klaus Moessner

Dr Francois Carrez

Overview

• Problem Domain

• Motivations and Objectives

• Contributions

– Adaptation Context Management

– Description Logics Based Rule Based Reasoning

• Implementation/Evaluation

• Conclusions

Terminology

• Adaptation

– Selection/generation/modification of content/services

for a delivery contexts upon user requests

• Delivery/Adaptation context

– device/network descriptions, user preferences and

characteristics, consumption environment description,

content and service metadata

• Content

– Text, image , video, audio or multimedia objects

• Services

– Delivery and presentation of content

Adaptation

• Static

– Generate different versions at authoring time

• E.g. BBC PC and Mobile versions

• Device centric

• Impossible to cover all delivery contexts

• Dynamic

– Generate the required version at request time

• Requires more computational resources

• User centric , offers personalization

• Important to gain and maintain customers

The Semantic Web Description Logics (DL) vs. Ontology vs. OWL

Ontology is a philosophical concept

– Study of concepts, being and existence

DL describes an ontology mathematically

– Using First Order Predicate Logic

– Powerful knowledge representation mechanism

OWL (Ontology Web Language)

– (XML + DL) based ontology language

– Latest version is OWL 2.0

Content Adaptation Domain

Complex

HeterogeneousDynamic/Volatile

Numerous Tools

Research Objectives

• Identify main problems and requirements of content and service

adaptation systems

• Evaluate available tools.

• Propose effective mechanisms to meet the identified

requirements.

• Investigate the use of Semantic Web technologies in content

and service adaptation

Adaptation Systems :

Problems and Requirements

• Problem: Heterogeneity

– Requires : Interoperability

• Problem: Dynamicity

– Requires : Extensibility, Maintainability

• Problem: Complexity

– Requires: Modularity, Management

Adaptation Management levels

ADMEADME

ADMEADME

ADMEADME

User

Context

Device

Context

ADME

Context

Content

Context

ADMEADME

General

ADTE

Specific

ADTESpecific

ADTESpecific

ADTE

Delivery

Channel

Delivery

Channel

Delivery

Channel

Content

Types

Content

Types

Content

TypesContent Selection

Context Management

Adaptation Decision Taking

Adaptation Execution Management

Delivery Management

This figure will need to be revised, and should be part of the state of the art (what do we

mean by management, can it be used in all stages ?)

Context Management

Adaptation Decision Taking

Contributions

• Extensible, maintainable, modular and

interoperable adaptation context processing

• Novel approach to extend the use of Description

Logics to rule based adaptation decision taking

Proposed Solution

Adaptation

Context Manager

Adaptation Manager

Adaptation Execution

Reasoning

ManagerAdaptation

Decision Engine

AM Gateway

Adaptation Context Management

Adaptation Context Issues

• Context is of paramount importance

• New context parameters / adaptation scenarios

need to be considered for personalization

• Need to manage the different context formats

– Of different syntax and vocabulary and semantics

• Issues that need to be addressed

– Hardcoded context formatting to internal model poses

extensibility and maintainability problems

– No focus on interoperability and extensibility

Proposed Solution

Hig

h-L

ev

el C

on

tex

t

Inte

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e

As

sim

ilatio

n C

on

tex

t Inte

rfac

e

MPEG7/21

ContextHigh | Low

Level | Level

ADO

UAProf

Extracted

context

Descreasing complexity


Adaptation

Decision

Taking

Ad

ap

tatio

n

Co

nte

xt

Ad

ap

tatio

n C

on

text

Higher Level Context

T1

Tn

Context

Reasoner

ADO : an Adaptation Domain Ontology T : Context Transformer / Formatter

Proposed Solution

Hig

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t

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rfac

e

As

sim

ilate

d C

on

tex

t Inte

rfac

e

MPEG7/21

ContextHigh | Low

Level | Level

ADO

UAProf

Extracted

context


Adaptation

Decision

Taking

Ad

ap

tatio

n

Co

nte

xt

Ad

ap

tatio

n C

on

text


T1

Tn

Context

Reasoner


Context Assimilation• Aims for

– Interoperability with existing

formats

– extensibility to new formats with

ease of maintenance

• Formal context modelling

– Description Logics + XML =

OWL

• Standard vocabulary

– MPEG-7/21

• Extensible formatting

– XSLT based

Proposed Solution

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on

tex

t

Inte

rfac

e

As

sim

ilate

d C

on

tex

t Inte

rfac

e

MPEG7/21

ContextHigh | Low

Level | Level

ADO

UAProf

Extracted

context



Adaptation

Decision

Taking

Ad

ap

tatio

n

Co

nte

xt

Ad

ap

tatio

n C

on

text


T1

Tn

Context

Reasoner


Proposed Solution

Hig

h-L

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el C

on

tex

t

Inte

rfac

e

As

sim

ilate

d C

on

tex

t Inte

rfac

e

MPEG7/21

ContextHigh | Low

Level | Level

ADO

UAProf

Extracted

context


Adaptation

Decision

Taking

Ad

ap

tatio

n

Co

nte

xt

Ad

ap

tatio

n C

on

text


T1

Tn

Context

Reasoner

Context Refinement • Define high level context concepts

– Act like adaptation rules

– Reduces decision taking complexity

– Reduces the impact of context

changes to the rest of the system

• Use latest features of OWL 2.0

– Data types reasoning

– Negative property assertions

Context Management

• The Adaptation Decision Interface Ontology

(ADIO)

– Internal context model

• Pre-reasoning Parameters/Functions

– Aims to enhance extensibility at minimal maintenance

– Aims to improve performance of context reasoning

Context Processing Stages

Context

Profile

Format

Context

Pre-

reasoning

Functions

Context

ProfileContext

Profile

Content \

Service

Extract

Context

Formatting

ToolFormatting

ToolFormatting

Tool

Refine

Context

Calc Pre-

Reasoning

Prameters

Adaptation

Request

ADIO

Refined ADIO

ADIO

ProcessInput / Output Input / Output

• Defines low level concepts based on

– MPEG-7- Multimedia Description Interface

– MPEG-21 – Digital Item Adaptation

• Defines high level concepts such as

•

•

•

ormat(mp4)supportedF ormat(mp4) requiredF mp4Limited

x Limitation bandwidth imitedBandwidthL

image)sModality(userPrefer edVideoLimit imitedBandwidthL

eryLimitedVideoDeliv

Adaptation Decision Interface Ontology

High Level concepts

• Example : defining BatteryLimitation based on

– Remaining battery

– Service battery requirements

–

• Variable x is assigned for each request :

– x = serviceBatteryRequirement

• Requires changing the ontology structure and

hence requires reclassification (not efficient)

• How extensible is context handling ?

xBattery remaining

• Assume we need to add

– user remaining battery preference ,

• E.g. User wants %20 of battery power remaining

–

– x = serviceBatteryRequ– userRemainingPref

– Requires changing the code that handles the ontology

– Not practical in such a dynamic domain

• Where user requirements and device/content

technologies change rapidly

Extending to new context parameter

xBattery remaining

Pre-Reasoning Functions/Parameters

Pre-reasoning parameters

• Avoid changing the ontology for each request

– Hence avoid reclassification and improve performance

• Extend to new context parameters with minimal

maintenance

Pre-reasoning Parameters

• Defining BatteryLimitation

– Remaining battery : r

– Service battery requirements : s

– User remaining battery preference : u

– A new data type property is created: batteryLimitation

•

• Pre-reasoning parameter: batteryLimitation

• Pre-reasoning function

– batteryLimitation = r - s – u

• Calculated for each request

• Does not requires changing the ontology

– Improved performance

0 mitation batteryLi

Managing Pre-reasoning Functions

• Represented as postfix expressions in XML

– Infix (a + b) – (c /d), Postfix b a + c d / -

– Postfix expressions are simpler to evaluate

– Extensibility and maintainability ensured by modelling

the postfix expressions in XML

Description Logics Rule Based Reasoning

Our Approach

• We use Description Logics and Ontology to

define adaptation rules

– Outside their use in state of the art (defining adaptation

concepts, e.g. Device, User, etc)

– To extend their expressiveness , for example to express:

Brother (A, B) , Father (A, C) Uncle (B,C)

• We implemented a Description Logics Rule Based

Reasoner for adaptation decision taking

Motivation

Semantic web is gaining momentum

– Description Logics is the cornerstone

– Continuous research on

• Expressiveness extensions

• Optimization techniques

Any platform that supports semantic web

– Will support a DL language and a DL reasoner

– Support of our approach would be straight forward

DL built in inference can be used to check

– Rule-base consistency

The DL based Rule Based Reasoner

Description Logics

Reasoner

Description Logics

based Rule Engine

Input : Context (ADIO)

Output : Adaptation Decisions

Rules Ontology

Pellet

Fact ++

Racer

The Approach

RuleBody RuleHead

The Approach : Structure

OWL:Thing

Rule

RuleBody

RuleHead

Equivalence

Sub-typing

Thing) : (OWLconcept op:

RuleHead RuleBody Rule

T


OWL:Thing

Rule

RuleBody

RuleHead

lassanonymousC namedClass premise_n

_.... premise_2 premise_1

npremise

Premise_1

Adaptation

Context

Premise_1Premise_1

Premise_1{Equivalence

Sub-typing


Body_n

Premise_1

Adaptation

Context

Premise_1Premise_1

Premise_1{

OWL:Thing

Rule

RuleBody

RuleHead

}_.... premise_2 {premise_1 Body_n npremise

Equivalence

Sub-typing

RuleBody Body_n


Body_n

Rule_n

Premise_1

Adaptation

Context

Premise_1Premise_1

Premise_1{

OWL:Thing

Rule

RuleBody

RuleHead

Equivalence

Sub-typing

Body_n Rule_n Rule Rule_n


Body_n

Head_n

Rule_n

Premise_1

Adaptation

Context

Premise_1Premise_1

Premise_1{

OWL:Thing

Rule

RuleBody

RuleHead

Equivalence

Sub-typing

Head_n Rule_n RuleHead Head_n


Body_n

Head_n

Rule_n

Premise_1

Adaptation

Context

Premise_1Premise_1

Premise_1{

OWL:Thing

Rule

RuleBody

RuleHead

conclusion

Decisions

conclusionconclusion

conclusion_1

Equivalence

Sub-typing

lassanonymousC namedClass conclusion

}_.... _2conclusion n_1{conclusio Head_n

nconclusion

Implementation and Evaluation

Evaluation

• Evaluation in adaptation systems

– Evaluation by implementation and functional testing

• Demonstrate the feasibility of the proposed

solutions

– Performance testing

• Demonstrates the applicability of the proposed

solutions

– Demonstration use cases

• Evaluate certain features of the system

• Essential for this research to evaluate

extensibility, interoperability and maintainability.

Adaptation Manager Implementation

rule-based

ADTE

DL-KB

DL- resoning

Handler

Context

Extractor

Context

FormatterA.Operations

Handler

AdaptationContext

Manager

MP

EG

-7

(MD

S)

F

Reasoning Manager

DL

ResonerAdaptation Decision Engine

DIA-based

ADTE

DL rules

reasoner

Adaptation Gateway

Clie

nts

Ma

ng

erWeb services

Interface

CA interface

Rule-based ADTE interface

Adaptation Manager

Me

ss

ag

e

Tra

ns

lato

r

Content

Adaptor

Content & Service

Providers

Adaptation

clients

MP

EG

-21

(DIA

) F

The Content Adaptation Test Bed

Content Server

&

Adaptation Mechanisms

Server

WLAN

Client

Gateway

Adaptation

Management

Framework 1

Adaptation

Management

Framework 2Client

Results

• Scenarios 1

– MOV Video - 3GPP Video

• Device does not support MOV

• Battery limitation

• Resolution limitation

• Scenario 2

– MOV Video - MP3 Audio

• Device does not support video

• User driving

Performance Testing

Demonstration Use Cases Evaluation

Use case 1

• Supporting a new context profile

– E.g. User Agent Profile UAProf

Supporting UAProf

• Step 1

– Implement the XSLT formatter

ADIO UAProf

Supporting UAProf

• Step 2

– Add the formatter to the system via the formatters XML

file

Demonstration Use Cases Evaluation

Use case 2

• Extending to the service summary scenario

– Service summary may be required if

• User is not interested in videos longer than

certain length

• User is commuting/in their brake and want to

choose from different service to view later

• Saving resources

Extending to the Summary Scenario

ength maxVideoL- hvideoLengt esholdyLengthThrvideSummar

0} resholdryLengthThvideoSumma {

ty(brake)}userActivi { (train)} onuserLocati ({ required-summary

• Extending the context model

Conclusions

• Identified main problems and requirements for adaptation

management systems

– Extensibility, interoperability, maintainability and modularity

• Introduced an context adaptation management to ensure

these requirements are met

• Implemented the Adaptation Manager, part of the content

adaptation test bed

– Demonstration use cases scenarios shows that the proposed

mechanisms enhance extensibility maintainability and

interoperability

• Description Logics is becoming a dominant reasoning tool

– A Description Logics based adaptation decision taking approach is

proposed

Publications

• Patent

– Apparatus and Method for Performing Service Adaptation in Respect of a Mobile Computing

Device , USPO No. 12/235,455, application filed in September 2008

• Journals/Conferences

– A. Attou and K. Moessner, "Context-Aware Service Adaptation Management," presented at

Personal, Indoor and Mobile Radio Communications, 2007, PIMRC 2007, IEEE 18th

International Symposium on, 2007.

– A. Attou, D. Jie, D. I. Laurenson, and K. Moessner, "Performance Modelling and Evaluation of

an Adaptation Management System," presented at Performance Evaluation of Computer and

Telecommunication Systems, 2008, SPECTS 2008, International Symposium on, 2008.

– A. Attou, N. Li, and K. Moessner, "Context for Multimedia Services Adaptation” in 4th

International Mobile Multimedia Communications Conference. Oulu, Finland, 2008.

– S. Merat, A. Attou, and A. Hamid, "Content Adaptation: Requirements and Architecture," in

Proceedings of the 10th International Conference on Information Integration and Web-based

Applications /& Services. Linz, Austria: ACM, 2008.

– N. Li, A. Attou, and K. Moessner, "A MPEG-based Ontology for Ubiquitous Content/Service

Adaptation," in Context Awareness for Proactive Systems, Third International Workshop on,

Proceedings-ISBN 978-0-9556240-0-1, Guildford , UK, 2007.

– N. Li, A. Attou, S. De, and K. Moessner, "Device and Service Descriptions for Ontology-Based

Ubiquitous Multimedia Services," in Proceedings of the 6th International Conference on

Advances in Mobile Computing and Multimedia. Linz, Austria: ACM, 2008.

– A. Attou , N, Li and K. Moessner, "Service Adaptation Management," Multimedia , ACM

Transactions On, Under Review, 2009.

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