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HANd : A New Transcoding Technique for PDA Browsers. Enrique Costa Montenegro Departamento de Ingeniería Telemática ETSI Telecomunicación Universidad de Vigo, Spain kike@det.uvigo.es. Introduction. HANd: Hierarchical Atomic Navigation New transcoding technique for WWW navigation on PDA
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HANd:A New Transcoding Technique for PDA Browsers Enrique Costa Montenegro Departamento de Ingeniería Telemática ETSI Telecomunicación Universidad de Vigo, Spain kike@det.uvigo.es
Introduction • 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
HANd philosophy • 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 (II) • 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 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
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?