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A Multi-Model XML (MMX) Framework for 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. Introduction.
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A Multi-Model XML (MMX) FrameworkforDigital 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
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>
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
Based on the data Classical “select * from” clause Can retrieve any item based on its attributes Queried by RDBMS
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 • 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 • 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
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