Semantic Information Access

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Semantic Information Access

• Atilla ELÇI
• Dept. of Computer Engineering
• Eastern Mediterranean University

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Semantic Info Access

• Shortcomings of common-place Web and search
  technology
• Applications of SemTech to knowledge access
• Semantic search and browse tools
• Natural language generation
• Device independence.
• Davies et al. Ch. 8.

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Shortcomings of Current Web and Search Technology

• Query construction
• Syntactic units such as keywords/terms are used.
• Polysemy multiple meanings
• Query ambiguity of keywords used per query
  (circa 2000) 2.2!
• Lack of semantics
• Inability to handle synonymy polisemy
• Missed semantic links
• Lack of context
• Missing the context to disambiguate the users
  query.
• Presentation of results
• Often too many results
• Managing heterogeneity
• Providing a coherent view of diverse sources and
  types of information very difficult and
  unsatisfactory at the best.
• ? Lots of data but lacking information!
• ? High recall but low precision!

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Advantages of Semantic Web Technology

• Resolving shortcomings of the current Web and
  search engines by
• Exploiting machine-processable metadata
• Using ontological concepts to define queries
• Using semantic relations in defining queries
• Providing information not simply data
• ? Future search engines must adapt to
  information-centric approach rather than
  document-centric one in order to seek
• Relevant sections not simply documents
• Digest of info from several docs/sections

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Semantic Search and Browse Tools

• Searching the XML
• QuizXML XML-aware search produces index map of
  keywords vs tags
• XSearch semantic search engine provides
  semantically-relevant document fragments in
  response to a query (tags keywords).
• XRANK XML search engine query term is matched
  against document content document markup.
  Extends Google Page Rank Algorithm.
• Searching semantic data RDF
• QuizRDF free-text search RDF annotation
  search. Provides searching browsing.
• Exploiting domain-specific knowledge
• Rocha et al.s Search Arch
• Spead activation keyword-based document search,
  and
• Using domain-specific semantic model
• Guha et al.s ABS (activity-based search)
  people, places, events, news items. Combines
  searching conventsional search engine and
  enhancing findings through semantic knowledge
  base (RDF annotation)
• Popov et al.s KIM (knowledge and information
  management) infrastructure, in order to enhance
  search
• Exploits ontological knowledge base
• Provides automated semantic annotation method

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Semantic Search and Browse Tools

• Searching for Semantic Web resources
• Swoogle Semantic Web Search Engine to find
  ontologies and related instance data on the Web.
• Other ontology search engines? Mostly for RDF
  (instance data).
• Wikipedia entry Semantic Search attempts to
  augment and improve traditional Research Searches
  by leveraging XML and RDF data from semantic
  networks to disambiguate semantic search queries
  and web text in order to increase relevancy of
  results.
• Study Googles search algorithm if you can find
  it.
• Take a look at the Alexa Web Search Platform
  search engine.
• Take a look at WebCrawler.com paradigm
  metasearch engine of search engines.
• At last, a semantic search engine See Hakia.com
• A Turkish initiative but in the USA. Check
  Partners, one of them is KVK.
• Just raised another US5 M totalling so far US18
  M.
• Another one PowerSet.
• Another recent one AskMeNow.

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Semantic Search Browse Tools (contd)

• Semantic Browsing
• Magpie plug-in that adds an ontology-based
  semantic layer onto the web pages as they are
  browsed.
• CS AKTiveSpace web application for UK CS
  research domain.
• Haystack a browser for semweb info agregating
  and visualizing RDF data from multiple arbitrary
  locations.
• W3Cs Annotea Project Amaya
• Yuces Site Insight.

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Natural Language Generation (NLG) from Ontologies

• Def. taking structured data in a knowledge base
  as input and producing natural language text,
  tailored to the presentational context and the
  target reader.
• Taxonomy / ontology verbalizers
• Template-based or text-generator-based
• Takes advantage of tax/ont hierarchy, user
  history, and available semantic annotation in KB.
• Exs. Wilcocks general purpose verbalizer,
  Ontogeneration Project
• Summarizers
• Ontosum using RDF triples
• Miakt domain- ontology-specific
• Approach
• Verbalize based on discourse schema
  active-action, passive-action, attribute,
  part-whole
• Semantic agregation

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Device Independence at Presentation Layer

• Skim through Sect. 8.4

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Advanced Semantic Querying

• Leveraging the Expressivity of Grounded
  Conjunctive Query Languages
• By Alissa Kaplunova, Ralf Möller and Michael
  Wessel
• PDF (325.7 KB)

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Conferences

• ESWC-08 Workshop on Semantic Search
• Workshop pf ESWC 2008, 1-5 June 2008, Tenerife,
  Spain.
• In recent years we have witnessed tremendous
  interest and substantial economic exploitation of
  search technologies. On the other hand semantic
  repositories and reasoning engines have advanced
  to a state where querying and processing of this
  knowledge can scale to realistic IR scenarios. As
  such, semantic technologies are now in a state to
  provide significant contributions to IR problems.
  This workshop intends to investigate the
  potential and the challenges of Semantic Search
  systems. Main topics of interest of the workshop
  cluster around the areas
• Tasks and Interaction Paradigms for Semantic
  Search,
• Query Construction and Resource Modelling for
  Semantic Search,
• Algorithms and Infrastructures for Semantic
  Search, and
• Evaluation of Semantic Search.

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Commercial Conferences

• Data Modeling Seminars and Workshops by Wilshire
  Conferences
• Designing and Building Ontologies An ontology is
  a formal description of the meaning of the
  information stored in a system. It resembles a
  conceptual model, but goes much beyond a
  conceptual model in that the formal definitions
  allow the system to infer class membership based
  on properties. Additionally, inference engines,
  running on ontologies, allow users to extract and
  integrate information stored in distributed
  systems. This workshop, which will contain a
  number of live demos and student exercises, will
  cover practical issues in employing ontologies.
  A 4-DAY Seminar with Dave McComb and Simon Robe,
  1795.
• DAMA Symposium Wilshire Meta-Data Conference
• 2007 Semantic Technology Conference

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References

• John Davies, Rudi Studer, Paul Warren (Editors)
  Semantic Web Technologies Trends and Research in
  Ontology-based Systems, John Wiley Sons (July
  11, 2006). ISBN 0470025964. Ch. 8. pp. 139-169.
• W3C Semantic Web Tools Wiki page
• Check Jena, SemWeb, Protégé, Swoop, etc.