A Multi-Model XML (MMX) Frameworkfor

Digital Video Library (DVL) Systems

Presented by: Jacky Ma

Date: 11 Dec 2001

Presentation Outline Introduction

Background An Example The Problem

The MMX Framework Models Syntax Behaviors

Conclusion Contribution Difficulties

IntroductionIntroduction

Background

Previous Research Digital Video Library (DVL) Extensible Markup Language (XML)

Motivation Facilitate searching in DVL with XML Search XML in specialized and customizable

way

An XML Example<key N="7" S="3" E="16" W="1"/><node id="1">

<key N="7" S="3" E="6" W="1"/><node id="1">

<key N="7" S="5" E="2" W="1"/><data x="1" y="5">itemA</data><data x="2" y="7">itemB</data>

</node><node id="2">

<key N="4" S="3" E="6" W="4"/><data x="4" y="3">itemA</data><data x="6" y="4">itemC</data>

</node></node><node id="2">

<key N="6" S="4" E="16" W="8"/><node id="1">

<key N="5" S="4" E="8" W="9"/><data x="8" y="4">itemG</data><data x="9" y="5">itemD</data>

</node><node id="2">

<key N="6" S="5" E="11" W="16"/><data x="11" y="5">itemF</data><data x="16" y="6">itemE</data>

</node></node>

Document

Element "Key"

Element "Node"

Element "Data"

Queried by XPath

Based on the XML structure and the data Retrieve the node “data” containing attribute

“x=8” //data[@x=‘8’]

Can also retrieve the parent-node, sibling-node, etc. /node[1]/node[1]/key/following-sibling::*

Useful in XSLT

Queried by RDBMS

id1

N1

S1

E1

W1

id0

N0

S0

E0

W0

x y data

1 7 3 6 1 1 7 5 2 1 1 5itemA

1 7 3 6 1 1 7 5 2 1 2 7itemB

1 7 3 6 1 2 4 3 6 4 4 3itemA

1 7 3 6 1 2 4 3 6 4 6 4itemC

2 6 416

8 1 5 4 8 9 9 5itemD

2 6 416

8 1 5 4 8 9 8 4itemG

2 6 416

8 2 6 511

16

11

5itemE

2 6 416

8 2 6 511

16

16

6itemE

Based on the data Classical “select * from” clause Can retrieve any item based on its

attributes

Queried by R-Tree

How about if I told you it is a R-Tree? Spatial Queries

Give me the point at (2,7) Give me the point nearest to (4,4)

Nearest Neighbor Search Give me the point nearest to “itemB”

(0,0)

What makes the difference?

Make use of knowledge we have on the data given.

We can do the spatial query ONLY if we know the data segment is representing a R-Tree, and understand what are the attributes (id, N, S, E, W, etc.) representing.

Problem

There are a lot of different data structures, different data manipulations, and different query methods.

How could we model them with XML?

The MMX FrameworkThe MMX Framework

The MMX Framework To solve the previous problem:

A framework allowing various data structures to be implemented upon

Knowledge on knowledge Describe the structural information of XML Document Empirical knowledge Analogeous to RDF

Manipulation of information with structural information Queries Updates Exchanging information

Model the “Models”

The kinds of “Models” is unlimited They may looks “similar”, all of them can

be represented by graphs or XML tree But the underlying structures, constraints

and algorithms are different No generic descriptive syntax Use a “label” and “procedural” approach

Label “known” structures, and Program the “new” structures

Major “Labeled Models”

Generic Object Vector Relational Document Tree

Basic Model

Abstract Data Object (ADO) Encapsulate the information about a package

of structured data Accessible at Root Pointing out at Child Node Includes:

Model Name Properties Behaviors Data

Abstract Data Object:Properties,Behaviours,

Data

Head Node

Leave Nodes

In References

Out References

Parent Node

Child Node

Child Node

Child Node

Out References

Syntax Serialization Syntax

Embedded in XML Document Defines elements like <ado>, <property>, etc. Easy to use Change the document instance

Schema Syntax Embedded in XML Document Schema Associate element names with structural information More complicated Do not need to change the document Favors reusability, scalability and interoperability

Behaviors

Behaviors The program to manipulate the data “Default” Behaviors allow operations on any

standard ADOs

Properties Persistent variables Keeping the state of the ADO

Data User data Appear as DOM Tree to the Behavior program

ConclusionConclusion

Contribution

Propose a representation to encapsulate data structures

A procedural model to manipulate the data Promote the use of interoperable data structure

format Describe how will typical “Models” functions Describe the “Tree” model which features spatial

queries, and particularly suitable for searching in DVL

Difficulties

No general syntax can precisely describe all kinds of data structures

Not possible to include all data structures one-by-one

Research Direction

Develop the full specification for the MMX Framework

Develop various structures that tailored for content-based searching in DVL

Q&AQ&A