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?

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