Refinement Correction Strategy for Invalid XML Documents and Regular - PowerPoint PPT Presentation

Refinement Correction Strategy for Invalid XML Documents and Regular Tree Grammars Martin Svoboda and Irena Holubova (Mlynkova) svoboda@ksi.mff.cuni.cz DEXA 2014 Munich, Germany September 2, 2014 XML and Web Engineering Research Group Charles University in Prague

Outline • Introduction • Corrections • Algorithms • Experiments • Conclusion Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 2

Introduction • Motivation  Incorrect XML data ‒ Well-formedness, schema validity, data consistency • Input  One XML document ‒ Well-formed but (potentially) invalid  DTD or XSD schema • Goal  Structural corrections of elements Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 3

Sample Correction • Document <a> <x><c/></x> <d><c/></d> <d><c/><a/></d> </a> • Grammar [a, C.D A *  A] [b, D B *  B] [c,   C] [d, C*  D A ] [d, A|B|C  D B ] Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 4

Edit Operations • Edit operations  Add leaf node  Remove leaf node  Rename node • Edit sequences  Insert new subtree  Delete existing subtree  Repair existing subtree ‒ With an option of node renaming Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 5

Edit Operations • Example renameNode(0,c), removeLeaf(0.0), renameNode(2.1,c) • Cost Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 6

Algorithm Idea • Recursive processing  From the root node towards leaf nodes…  … and at each particular data tree node…  … correct a sequence of its child nodes • Example C.D A * Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 7

Horizontal Correction • Automaton traversal  Start ‒ Before the entire node sequence ‒ At the initial automaton state  Step ‒ Before some particular node (if any) ‒ At some particular automaton state  End ‒ After the entire node sequence ‒ At one of the accepting states Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 8

Correction Multigraphs • Structure  Vertices  Edges Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 9

Shortest Paths • Paths  Source  Targets Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 10

Intent Repair • Structure Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 11

Intent Signatures • Observation  Different intents may lead to identical repairs ‒ We do not need to evaluate them repeatedly • Solution  Intent signatures  Repairs caching Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 12

Correction Strategies • Strategies  Default  Exploring  Refinement Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 13

Refinement Strategy • Observation  Until now we always worked with… ‒ … fully evaluated nested intents ‒ … and therefore their final costs • Idea  Refinement exploration based on estimations Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 14

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Refinement Strategy • Exploration loop  Complete vertex ‒ Explore outgoing edges ‒ Obtain first cost estimations ‒ Update current distances  Incomplete vertex ‒ Request refinement of open perspective ingoing edges • Assign a quota to limit the allowed refinement progress Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 28

Execution times • Refinement strategy 4 Time in seconds 3 2 1 0 10k 20k 30k 40k 50k 60k 70k 80k 90k 100k Number of nodes Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 29

Conclusion • Features  Regular tree grammars  Compact repair structure  All minimal corrections  No parameters required  Nearly linear algorithms Refinement Correction Strategy for XML Documents September 2, 2014 DEXA 2014, Munich 30

Thank you for your attention… Faculty of Mathematics and Physics Charles University in Prague