OntoBlog: Linking Ontology and Blogs

Aman Shakya 1, Vilas Wuwongse 2, Hideaki Takeda 1, Ikki Ohmukai 1

1 National Institute of Informatics, Japan

2 Asian Institute of Technology, Thailand

SAAKM 2007, Whistler, Canada

Contents

• Background– Semantic Blogging– Semantic Annotation

• Semantic Blogging as Semantic Annotation

• The OntoBlog platform• Application Scenario• Implementation• Some experiences• Related Work• Conclusions and Future Work

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Background

• Blogging– Publicly accessible web-based publication of

periodic articles usually in reverse chronological order

– Easy authoring platform – Unstructured– Filtering, organizing, navigating is difficult

• Semantic Blogging– Provides semantic structure to blog items– Enrich blog entries with metadata– Combine features of Blogging and the Semantic

Web– Informal knowledge management

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Semantic Annotation

• Annotation– comments, notes, explanations or remarks

attached to any document or a selected part of the document

• Semantic Annotation– Annotation that references an Ontology– Identifies concepts and relations in documents– Intended for machines

• Significance of semantic annotation– Enhanced information retrieval– Improved interoperability (Uren et al. , 2006)

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Semantic Blogging as Semantic Annotation

• Semantic blogging may be viewed as semantic annotation to blog entries

• Link blog entries to pre-existing Ontology and instances

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Linking Blogs and Ontology

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Blog entries OntologySemantic Annotation

Semantic Blogging as Semantic Annotation (contd..)

• Rich semantic structure of ontology can enable useful semantic capabilities

• Semantic annotation can help to– Retrieve relevant resources– Navigate meaningfully– Categorize and organize contents

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Semantic Annotation in Blogs

• Blog entries are self-contained snippets or small contents

• Blogs are used as easy platform for frequent personal publishing

• Considerations for semantic annotation– Integrated authoring environment– Automation– Integrated services

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The OntoBlog Platform• Semantic Annotation

– Annotate blog entries with existing ontology instances

• Integrated Authoring– Authoring and annotation of blog entries

• Semi-automatic Annotation– Suggest related instances automatically

• Integrated Services– Semantic navigation, search and organization

• Feedback for Ontology Maintenance– Suggest new concepts and instances

Online demo - http://dutar.ex.nii.ac.jp/ontoblog/blog/default/

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Application Scenario

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System Architecture

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Publishing Metadata

• Blog entries may have content metadata• E.g., SWRC metadata for bibliography• Stored as RDF triplets• Metadata is exported in RSS feeds

Ontology• Example ontology

– Computer science department ontology– Based on SHOE computer department

ontology

• Populated and maintained using Protégé

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Example Ontology

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Inference

• for_course has_topic• is_broader_than is_narrower_than• teaches taught_by

– Inverse relations

• has_prerequisite , is_broader_than – Transitive relations

• Used OWL Micro reasoner from Jena

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Blog-Ontology Linking

• Link Blogging existing Ontology system– using Semi-Automatic Semantic Annotation

• Manual annotation– Cumbersome and error-prone– May depend on willingness of users– Authenticity and quality not guaranteed

• Annotation can be automated by simple language processing techniques– can be very fast and quite effective

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Blog-Ontology Linking

• Each concept has a “keywords” element• For each instance, the “keywords” element

contains a collection of related words• Stemmed blog entries matched against

stemmed “keywords” to discover related instances– Porter Stemming

• Related instances automatically suggested when adding/updating blog entries

• Discovered relations stored as related-to property (if the user approves)

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Authoring Blog Entry

Next…

Suggestions for semantic annotation

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Blog-Ontology Linking

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Blog-Ontology Linking

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InstanceInstances in s in

OntologyOntology

Blog Blog EntrieEntrie

ss

Semantic Navigation

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Semantic Search• Simple implementation just to demonstrate

applicability of semantic search• Augment traditional search results

– Return blog entries linked to semantically related instances

• Useful when text search alone does not produce enough results

• Depth of semantic search can be controlled• Semantic search can be enabled or disabled

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Semantic Aggregation• Collect and organize search results relevant to a

topic of interest

Algorithm1. Get all relevant blog entries from search2. Find the set of instances linked to each blog entry3. Find all relations between the instances4. Visualize the related instances as directed graphs

• GraphML used

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Semantic Aggregation

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Search Search resultsresultsRelated Related

EntriesEntriesclick

Feedback for Ontology Maintenance

• If related instances or concepts are not present in the Knowledge Base– users may suggest a suitable instance and/or

concept

• Provides web-based form for new suggestions along with the automatic suggestions

• Feedback from users is useful for the administrator/knowledge engineer to maintain the ontology – by adding missing concepts and instances or

refining them

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Feedback form for suggesting new Concepts/Instances

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Some Experiences

• Simple test experiments• About 100 dummy blog entries related to

different courses, topics, researches, etc populated manually

• 10 students from the Computer Science department of the Asian Institute of Technology helped in the tests

• Automatic blog-ontology linking– 84% right suggestions

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Semantic Search Results

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Some Experiences

• User Feedback– Many features are subjective and difficult

to evaluate by experiments– Positive user response for most of the

features– Not easy to judge relevance of semantic

search results

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Related Work• Semantic Blogging

– Semantic Blogging Demonstrator (HP labs)

– Semantic Blogging using Haystack (Karger & Quan)

– Semblog (Ohmukai & Takeda)

– semiBlog (Möller et al.) (now renamed “Shift”)

– SocioBiblog (Shakya et al.)

• Semantic Annotation– semi-automatic semantic annotation – S-CREAM,

extraction ontologies, etc– Magpie– Mangrove– KIM

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Conclusions• Linking Blogging and Ontology management technologies• OntoBlog – Semantic Blogging prototype

• Semi-automatic annotation of blog entries with existing instances of an Ontology

• Integrated platform – semantic authoring, annotation and information utilization

• Semantic structure of ontology can enable semantic capabilities Navigation and Search in blogs

• Feedback for ontology maintenance through blogging

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Future Work

• Decentralized collaborative approach for Ontology– Folksonomy, Semantic Wiki, etc

• Semantic capabilities across multiple blogs• Enhance inference capabilities• Incorporate mature semantic search• Ranked information retrieval• Sophisticated language processing

– WordNet, IE (with supervised/unsupervised learning)

• Support semantic blogging clients like semiBlog

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Thank you !

• Questions / Suggestions

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