Joshua Taylor 20080918 Presentation
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- Presentation Given at: CSCI 6966 Advanced Semantic Web (Fall 2008) - Lesson 4
- Speaker: Joshua Taylor
- Title: History Matters: Incremental Ontology Reasoning Using Modules
- Authors: Bernardo Cuenca Grau, Yevgeny Kazakov, Christian Halaschek-Wiener
- Conference: ISWC 2007
- URL: http://iswc2007.semanticweb.org/papers/183.pdf
- Date of Presentation: 2008/09/18
- Presentation Slides : File:HistoryMatters-slides.pdf
Questions
| ID | Question | Name | Answer |
|---|---|---|---|
| Grau2007history question 1 by lebo | The authors open the abstract by stating, "The development of ontologies involves continuous but relatively small modifications." A reasonable first step to reduce the ontology development cycle is to tackle the problem addressed in the paper: classify ontology O^2 by reusing the "evidences" from the classification of O^1, the set of added axioms, and the set of removed axioms. Their "module" technique can then be applied at each committed change. This addresses the relatively small modifications aspect of ontology development,
|
Tim Lebo | |
| HistoryMatters GregoryToddWilliams Question1 | The Gene Ontology seems to be the only ontology for which update sizes are varied during evaluation (with n=1,2,4) whereas the other ontologies are all tested for a fixed update size. Are the gains in reclassification time seen in the results expected to be the same across all ontologies, regardless of update size? Furthermore, is the seemingly narrow range of tested update sizes (1-4) expected to approximate real-world usage? Would the same gains be seen with updates of different characteristics such as unbalanced axiom removal/addition counts or larger updates (tens or hundreds of affected axioms)? | Gregory Todd Williams | |
| Joshua Taylor 20080918 Presentation Jesse Weaver |
What is the time complexity of the proposed algorithm with respect to the number of subsumptions that change their entailment status? One of the main assumptions proposed in section 3 is that "the number of subsumptions that change their entailment status w.r.t. the ontology ... is probably small compared to the number of subsumptions that do not ...." What about when mapping ontologies? For example, consider the paper "Collecting Community-Based Mappings in an Ontology Repository". In that paper, users are allowed to map certain relationships between ontologies. These mappings do not use OWL properties but rather properties indicating, for example, that two classes _could_ be considered equivalent (among others). Now imagine a user selects an ontology to add to his/her own preexisting ontology, replacing those "could-be-considered-equivalent-class" relations (between the two ontologies) with actual owl:equivalentClass relations for purposes of reasoning over data that uses both ontologies. This seems like a plausible situation in which the aforementioned assumption may not hold. What kind of results would be gotten from experiments reflecting this ontology-mapping example? A casual question of interest: How could such an incremental approach be applied (if at all) to promote reasoning in large and/or distributed RDF stores? |
Jesse Weaver | |
| Joshua Taylor 20080918 Presentation Joshua Taylor 1 | As described in Section 6 "Empirical Evaluation", in step 3 the authors "extracted the minimal locality-based module for each atomic concept". However, the only method for extracting modules seems to be Algorithm 1, about which is stated "Finally, we point out that the modules extracted using Algorithm 1 are not necessarily minimal ones. That is, if O ⊨ α, the computed module might be a strict superset of a justification for α in O, and if O ⊭ α then the module for Sig(α) might not necessarily be the empty set." Then how is a "minimal locality-based module for each atomic concept" produced? | Joshua A. Taylor | |
| Joshua Taylor 20080918 Presentation Joshua Taylor 2 | Quoth the first paragraph of Section 6 "Empirical Evaluation", "Our system implements a slightly more simplistic procedure than the one in Algorithm 2; in particular, once the affected modules have been identifies, our implementation simply reclassifies the union of these modules using Pellet to determine the new subsumption relations, instead of using the procedure described in lines 20–34 of Algorithm 2." Does this have any significant effect on the results? | Joshua A. Taylor | |
| Joshua Taylor 20080918 Presentation Joshua Taylor 3 | In the evaluation, random axioms are selected to be added and removed for incremental changes. It seems more likely that an ontology developer might re-evaluate the semantics of a particular concept, and that these changes might be to a slightly larger number of axioms, but affecting a smaller number of modules (than if randomly selected axioms were changed). How does this affect evaluation? | Joshua A. Taylor |
Attendees
| A | Presentation +, and Presentation attended by Tim Lebo + |
| Conference | ISWC 2007 + |
| Date | 18 September 2008 + |
| Given at | CSCI 6966 Advanced Semantic Web (Fall 2008) - Lesson 4 + |
| Paper has author | Bernardo Cuenca-Grau +, Yevgeny Kazakov +, and Christian Halaschek-Wiener + |
| Speaker | Joshua A. Taylor + |
| Title of paper | History Matters: Incremental Ontology Reasoning Using Modules + |
| Url | http://iswc2007.semanticweb.org/papers/183.pdf + |
