Priorisation in Segmentation of XML Documents

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Priorisation in Segmentation of XML Documents
Distributed XML

• Markus Ylikerälä
• Sampsa Toivanen

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Motivation

• Increasing market of mobile devices
• Rapid development of hardware
• Limited bandwidth
• Data sharing with peer-to-peer (P2P) technology

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Problem

• Why would someone like to consume his or her
  mobile host's battery and pay for the use of
  bandwidth for someone else?

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Framework
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Objective
XML Document
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Focus

• XStream
• Segmentates XML tree in level-order
• Speeds up data transmission over bad quality
  wireless connections
• Our focus is to improve the XStream
• Priorisation of XML elements
• More versatile tree traversal schemes

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A Simple Example
The effect of priorisation on the waiting queue
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Another Example
A subtree is processed before continuing the
default level-order traversal
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Priorisation

• Priorities are assigned to elements using
  metadata
• XPath is used to specify a set of elements
• Priority values range from Inf to Inf
• Mapping between element sets and priority values

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Potential Uses

• Benefits yielded by priorisation vary
• Priorisation is useful for
• Highly structural XML documents
• Large XML documents
• Poor connections

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Use Case SVG

• Scalable Vector Graphics (SVG)
• W3C Recommendation for representing vector
  graphics in XML
• Large file sizes
• Grouping of elements
• Currently in use, waiting for a breakthrough

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Future Work

• Implementation
• Evaluation
• Comparison with Xstream

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Conclusions

• Improvement of distributing XML documents to
  mobile hosts
• Our XML Priorisation enhances Xstream
• Evaluation is still needed