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Tools for Semantic Annotation

Atilla ELÇİDept. of Computer Engineering

Eastern Mediterranean University

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Semantic Annotation

• Transcoding:Transformation of info from one form to another

• Web content transcoding if along the Web transaction path– Objective: repurposing– Available externally:

• Can’t be internally due to HTML being rigid.• Even if inserted, not recognized (skipped) by

browsers

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Annotation: Passin Ch. 4.

Def.: The act of adding notes (WordNet)

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Annotation continued

Semantic Web can play an important role in improving the role of annotations through following features:

• Annotation discovery by agents• Machine-understandable annotation• Intelligent filtering of annotations (need annotation

metadata)• Improved searching• Enhancement by agents• Collaboration over annotations and supporting

data• Information extraction

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Web Annotation Systems

• Inline editing: download & edit an HTML page and save in your domain

• External annotation: browser first downloads a page and its annotation (from your domain or other server) then merges them on the fly and displays

• External server creates annotated view and serves itImportant criteria to consider:• Ownership of annotations• Tool becoming obsolete / unavailable• Server scalability

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Current Web Annotation Systems

• Wiki Collaboratives: allows members to edit Web content on the fly. Check a dictionary. Examples:– The original Wiki by Ward Cunningham– Wikipedia and others of Free Encyclopedia Project– Ontolog Wiki

• W3C Annotea Project and Amaya editor-cum-browser. Uses RDF to describe annotations.

• Multivalent Browser: – Multivalent Home Page – Wikipedia entry.

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External Annotation Framework

• Ref.: Hori; and in ACM PD Bookshelf.• Def.: A scheme for representing annotation files and a way of

associating original documents with external annotations.

-Contains metadata adressing part of the Web document.

- XPath & XPointer are used to link the two.

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Annotation File

• RDF/XML syntax is used.

                                                    

Figure 14.2: Framework of external annotation.

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Annotation Rendering:Client Preference & Capability

• Content adaptation requires dealing with Client Feature Set:– User preferences– Device capabilities.

• W3C’s Composite Capability / Preference Profiles (CC/CP) is used in describing such information profiles.

• CC/PP specifies that client profiles can be delivered to a proxy server over HTTP.

• Thus proxy server is able to consider together the original document, annotation(s) on it, and client’s CC/PP specs in transcoding the content.

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Annotation-Based Transcoding System

• Transcoding Architecture: Abstract architecture based on intermediary (proxy) between client & server.

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Ex: Page Splitting

• Annotation vocabulary:

“pcd” consists of:– Alternatives,– Splitting hints

(a in the ex.),– Selection criteria

(b in the ex.)

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Ex: Page Splitting (continued)

• Adaptation engine:

Information Extraction (IE) (Bontcheva et al @Davies Ch. 3)

≡ A technology based on analysing natural language in order to extract snippets of information and produce fixed format, unambiguous data as output.

Types of info sought (ref. Message Understanding Conference, MUC-7, definitions:

1. Entities (NE): such as people, places, organizations, quantities of commodities, dates, etc.

2. Mentions (CO): places of references to entities in the text

3. Descriptions (TE): of the entities

4. Relations (TR): between entities

5. Events (ST): involving entities

Semantic annotation: assigning to entities and relations in the text links to their semantic descriptions in an ontology.

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HLT & Semantic WebFigure 3.1 in Bontcheva et al @ Davies

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Applying IE in SemWeb: Traditional Cases

• “Traditional” IE: annotating with metadata; ontology is not incorporated into annotated text such as Web pages:– AeroDAML annotation tool (2001): auto generates DAML annotations from

Web pages

– Amilcare IE system (2003): a machine learning system that produces extracted info in triples for use by an anno’n tool

– MnM semantic anno’n tool (2002: semi-auto; piggy-backed to Amilcare.

– S-Cream (2002): auto anno’n using Onto-O-Mat manual anno’n tool implementing CREAM framework for creating relational metadata, and Amilcare

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Applying IE in SemWeb: Ontology-Based Cases

• Ontology-based IE: annotating using a formal ontology as one of the system’s resources:– Pankow (Pattern-based Annotation through Knowledge on the Web,

2004): gathers surface pattern wrt a given ontology. • <instance> <concept>, <instance> is a <concept>

• Checks validity through google queries

• Auto performance: 24.9 % against human perf of 62.09%; semi-auto: 49.56%

– SemTag: large-scale semantic anno’n wrt TAP Ontology.

– KIM (Knowledge and Information Management system by OntoText Lab, 2005): now taken over by SEKT Project.

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Semantic HTML?

• W3C has now issued a draft HTML 5 aiming to formalize semantic annotations as next version of HTML tag vocabulary:– Tony Patton's blog– Differences of HTML 5 from prev version– HTML5 specs

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References

• Thomas B. Passin. Explorer’s Guide to the Semantic Web, Manning 2004. Ch4.

• Masahiro Hori: Semantic Annotation for Web Content Adaptation, Ch. 14 in Spinning the Semantic Web, (Ed.: Dieter Fensel et al.), MIT Press, 2003. (Check ACM Digital Library Books at Professional Development Center)

• Adobe’s annotation reference.• Yuce’s thesis project.• Bontcheva et al.(2006). Semantic Annotation and Human Language

Technology. Ch. 3 in Semantic Web Technologies, Davies et al (eds). Wiley.