hand : a new transcoding technique for pda browsers enrique costa montenegro departamento de...
TRANSCRIPT
HANd:A New Transcoding Technique
for PDA Browsers
Enrique Costa Montenegro
Departamento de Ingeniería Telemática
ETSI Telecomunicación
Universidad de Vigo, Spain
• HANd: Hierarchical Atomic Navigation
• New transcoding technique for WWW navigation on PDA
• Keeps all original information
• One navigator page and several atomic pages
• Replaces unreadable elements by icons
Introduction
• Fragmentation of original page into zones• Zones are sets of elements (pictures, links,
text, tables...)• Only one zone is displayed at original scale• Navigator page: a reduced overview of the
original page, with links to atomic pages• Atomic pages: readable elements or zones,
pieces of the original page
HANd philosophy
• Representations of elements– Reduced version: if readable– Representative icon: if reduced element or zone is
unreadable
• Dependence between elements: an element is unreadable if all its descendants are unreadable
• Navigation page: representatives in the same relative locations of original elements
HANd philosophy (II)
HANd example
HANd example (II)
HANd example (III)
HANd example (IV)
HANd example (V)
HANd page generator
• Two stages– Preprocessing stage– Conversion stage
HANd Page Generator (II)
• Preprocessing stage– Input: HTML documents– Conversion of HTML to XHTML using Jtidy– Obtain DOM tree from XHTML using a DOM
parser– DOM tree: representation of XHTML
document as a tree of nodes, each node is an element of the XHTML document
HANd Page Generator (III)
• Conversion stage– Input: DOM Tree– Apply visibility and transformation rules to
DOM Tree– Obtain new DOM trees– Convert new DOM trees to navigation page and
associated atomic pages
Transformation rules: readability
• A PDA-to-PC screen area ratio is calculated, R<1, used to reduce elements
• Text: new font area is calculated, move to atomic page if not readable
• Images: new size is calculated, if original picture is small enough, it wont be resized
• Readability threshold, label unreadable elements with 1, 0 otherwise
Transformation rules: pruning
• Labels are propagated across the DOM tree
• Branches without 0 labels are pruned
Transformation rules: results
• Nodes with label 0 (readable) are substituted with reduced representatives
• Nodes with label 1 (unreadable) are replaced by an icon, with a link to the atomic page with the original information
• Adjacency rule: all adjacent icons associated to elements of the same type are represented by a single icon
Transformation rules: example
Conclusions
• HANd: New Transcoding Technique for PDA
• Advantages– No information loss: all elements in atomic
pages– Navigator page: readable overview of the
original page– Valid for all WWW documents and navigators
Questions!!
Example:
What is the ´d´ in HANd?
The End