1

Multimedia services over networks

Service provider

Service client

Service registry

Publish

Discovery

BindMultimediasystem

Review/backgroundFramework/Architecture

Deployment/Management

MultimediaServicesDelivery

Transactions/mobility/locations

2

Multimedia services delivery

• Zhiwen Yu and Daqing Zhang: Middleware Support for Context-Aware Ubiquitous Multimedia Services. Handbook of Research on Mobile Multimedia. (pdf ).

• Conor Muldoon, Gregory M. P. O'Hare, Rem W. Collier, Donnacha Phelan, Robin Strahan: Intelligent Delivery of Multimedia Content in a Device Aware Ubiquitous Environment. Multimedia Information Systems 2005: 131-145, (pdf)

• Zhou Wang and Hend Koubaa: Discovering Multimedia Services and Contents in Mobile Environments. Handbook of Research on Mobile Multimedia (pdf)

• Ricky Robinson, Jadwiga Indulska: A Context-Sensitive Service Discovery Protocol for Mobile Computing Environments. ICMB 2005: 565-572, (pdf)

3

Context-aware multimedia service

• Context information– Time– Location– Device capability– User preferences

4

Example

• Stopping vs. moving

SDTm

A B

NTNU, Trondheim

A

B

MC

S

Nb

D

D: Distance of movement S: Speed of mobile hostNb: Wireless bandwidth

M: Amount of data transferedTb: Battery life-time

bs N

MT

Ts < Tm < Tb

5

Context Management

ContextAggregation

ContextReasoning

ContextLearning

ContextQuery

Userprofiles

Situation

Query

ServiceClientsContext

Service

6

Context representation model

7

Context ontology

User situation UserPreference onMedia

Capability of mediaterminal

8

Context-aware multimedia architecture

9

10

Intelligent Delivery of Multimedia Content in a Device Aware Ubiquitous Environment• GLIDE

– Generic Language of Interface DEvelopment• Context-aware ubiquitous environments• Enforce a coding structure on the implementation of

interface components– Re-use and Extensibility

• Enable GUI independence– Among interface components– Between interface components and agents

• How?– Avoid object references– Use of agents

11

Agents

Clients ServerClient agents Server agents

Specifying the type of device

Adaptive GUI components

• Prevent inter-component dependencies– Decoupling

• Reuse of interface components• Dynamic restructured GUI Pros and Cons

12

GLIDE

Hardware•PDAs•CellphonesSoftware•J2ME-CDC•CLDC

13

GLIDE framework

• Factories– A class that returns an instance of a particular interface

component

• Interactions– Defines a dependency that a component has on another

component or agent

Composite objectGLIDE Instance GUIcreated

Handling•Interactions

14

GLIDE development process

PDAs

Cellphones

15

GLIDE grammar

Factory•Which Java class whild be loaded to create service specific GUI componentsInteracts•Define how the composite objects map interactions to entities

•Entities can be components or agents

16

Dynamic restructuring GUI

•Resources•User’s behaviors From Interface

To delivery content

17

Discovering multimedia services and contents

• Context awareness– When– Where

• Service discovery model– Broadcast– Centralized service directory– Distributed service directories

18

Broadcast model

Pull vs Push

19

Centralized directory model

1. Locating directory2. Service registration3. Service lookup4. Searching

Examples: JINI, INS

20

Distributed service directories

• Service discovery is a service• Interoperability• Asynchronous service discovery• Semantic service discovery

21

A Context-Sensitive Service Discovery Protocol for Mobile Computing Environments

• Discovery service– Query preferences

• Allow tailoring query results– Query ranking when multiple resources are matched

• Context-sensitive application– Context-aware– Adjust its behavior when the context changes

• If resource discovery protocols are context-sensitive, then results are dependent upon the context of the query

22

Discovery framework

• Persitent queries– Synchronous matching service– Asynchronous newly matching server

• Elvin engine (asynchronous messaging system - should try)

• Transient adversements– Information is meaningful only at the time of advertisement– Results are not stored

• Sub-queries• Named queries

23

Context-sensitive query

24

Preference model and language

25

Application iCarpark

26

Application iCarpark - cont

Issues:-Technologies

-Location direction-RFID readers-On-car computers

-Performances