Presented by: Jacky Ma Date: 11 Dec 2001 A Multi-Model XML (MMX) Framework for Digital Video Library (DVL) Systems Presented by: Jacky Ma Date: 11 Dec 2001

Presentation Outline Introduction The MMX Framework Conclusion Background An Example The Problem The MMX Framework Models Syntax Behaviors Conclusion Contribution Difficulties

Introduction

Background Previous Research Motivation 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"/> <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> <key N="6" S="4" E="16" W="8"/> <key N="5" S="4" E="8" W="9"/> <data x="8" y="4">itemG</data> <data x="9" y="5">itemD</data> <key N="6" S="5" E="11" W="16"/> <data x="11" y="5">itemF</data> <data x="16" y="6">itemE</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 Based on the data Classical “select * from” clause Can retrieve any item based on its attributes id1 N1 S1 E1 W1 id0 N0 S0 E0 W0 x y data 1 7 3 6 5 2 itemA itemB 4 itemC 16 8 9 itemD itemG 11 itemE

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”

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 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

Syntax Serialization Syntax Schema 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 Properties Data 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

Conclusion

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&A