Towards a component-based framework for developing Semantic Web applications

1
Towards a component-based framework for
developing Semantic Web applications

• Raúl García-Castro, Asunción Gómez-Pérez, Óscar
  Muñoz-García, Lyndon Nixon
• rgarcia,asun,omunoz_at_fi.upm.es
• ASWC - Bangkok, Thailand
• 4 February 2009

2
Motivation
?
?
Companies and particulars are changing from
Semantic Web technology consumers to producers
Semantic Web Framework

• Obstacles
• Which types of technology exist?
• Which are their functionalities?
• Which are their dependencies?
• How can I (re)use it?
• How can I include it into my application?
• Can these technologies interoperate between
  themselves and with my technology? How?
• How much does it cost to include semantics into
  my applications?
• How many people do I need to build a semantic
  application from scratch?

3
Index

• State of the Art
• Semantic Web Framework
• Components of the SWF
• Example use case
• Conclusions and next steps

4
State of the Art

• Component-based Software Engineering
• The process of defining, implementing and
  composing loosely coupled independent components
  into systems
• Relies on
• Independent components specified by their
  interfaces
• Component standards that facilitate their
  integration
• Its own development process
• Advantages
• Reuse components already developed and tested
• Applications built in a robust and rapid way

5
State of the Art II

• Software Architecture
• Fundamental organization of a system
• Consists on
• Components
• Dependencies between components
• Application environment
• Principles guiding design and evolution of the
  application
• Software Frameworks
• Domain-specific software architectures
• Classification
• Horizontal Frameworks valid for every application
  domain
• Vertical Frameworks developed for a concrete
  application domain

6
Index

• State of the Art
• Semantic Web Framework
• Components of the SWF
• Example use case
• Conclusions and next steps

7
What is the Semantic Web Framework?

• The Semantic Web Framework is a structure in
  which Semantic Web applications can be organized
  and developed
• It is a reference framework that
• Describes the existing types of SW technology,
  their functionalities, and the dependencies
  between these technologies
• Facilitates technology reuse by providing
  specifications and guidelines
• Shows how to achieve interoperability with SW
  technology
• Helps in making decisions when developing SW
  applications

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Design principles of the SWF

• Developer oriented, considering different
  audiences such as developers with low expertise
  with SW technologies
• Easy to understand. Components organized in
  dimensions, according to the major properties of
  the problem space that have significant variation
  over SW technology
• Inexpensive to adopt. Developing a SW application
  or upgrading an existing application with
  semantic capabilities should be easy, minimizing
  the impact on legacy systems
• Component based, defining specifications of the
  components that allow for different
  implementations of them, providing each of these
  components a basic functionality
• Semantics focused, describing only the components
  that provide semantic functionalities and
  functionalities to manage semantics
• Evolving. Easy to extend by inserting new
  components or modifying existing ones

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Index

• State of the Art
• Semantic Web Framework
• Components of the SWF
• Example use case
• Conclusions and next steps

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Components of the SWF

• Autonomous and modular units with well defined
  interfaces that describe a service and perform a
  specific functionality
• Used independently or together to develop
  Semantic Web applications
• Can be of four types
• Applications
• Part of applications (plug-in)
• Services
• Program libraries

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Dimensions of the architecture

• Components have beed classified according to the
  specific problems that they deal with
• Data and metadata management
• Querying and reasoning
• Ontology engineering
• Ontology customization
• Ontology evolution
• Ontology instance generation
• Semantic Web Services
• Dependencies between these components have been
  identified.

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Semantic Web Framework
Web Service registry
Web Service discoverer
Web Service selector
Information directory manager
Web Service composer
Ontology editor
Ontology discovery and ranking
Web Service choreography engine
Ontology repository
Ontology browser
Instance editor
Query answering
Ontology localization and profiling
Ontology evolution manager
Web Service process mediator
Data repository
Manual annotation
Ontology evaluator
Semantic query processor
Ontology adaptation operators
Ontology evolution visualizer
Automatic annotation
Ontology learner
Alignment repository
Web Service grounding
Ontology view customization
Semantic query editor
Ontology versioner
Ontology matcher
Web Service profiling
Ontology populator
Metadata registry
SEMANTIC WEB SERVICES
ONTOLOGY INSTANCE GENERATION
QUERYING AND REASONING
ONTOLOGY ENGINEERING
ONTOLOGY CUSTOMIZATION
DATA METADATA MANAGEMENT
ONTOLOGY EVOLUTION
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Example Ontology instance generation
Instance editor
Handles the storage and access to data and
annotated data
Handles the storage and access to ontologies and
instances
Data repository
Ontology repository
DATA METADATA MANAGEMENT
Instance editor
Creates and modifies ontology instances
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Ontology instance generation
Instance editor
Manual annotation
Data repository
Ontology repository
DATA METADATA MANAGEMENT
Manual and semi-automatic annotation of digital
content documents (e.g., web pages or images)
with concepts in the ontology
Manual annotation
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Ontology instance generation
Automatic annotation
Instance editor
Manual annotation
Data repository
Ontology repository
DATA METADATA MANAGEMENT
Automatic annotation of digital content documents
(e.g., web pages or images) with concepts in the
ontology
Automatic annotation
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Ontology instance generation
Automatic annotation
Ontology populator
Instance editor
Manual annotation
Data repository
Ontology repository
DATA METADATA MANAGEMENT
Ontology populator
Generates instances of a given ontology from a
data source
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Component implementations

• Existing component implementations have been
  identified

Query answering
...
KAON2
Fact
RacerPro
Pellet

• User interface
• Programming interface
• Service interface

IN
Query answering
OUT
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Index

• State of the Art
• Semantic Web Framework
• Components of the SWF
• Example use case
• Conclusions and next steps

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Example use case
Semantic Aggregation of News Stories

• Aggregated news service with the following
  requirements
• Accurate search
• Thematic Clustering
• Classification of news stories
• E-mail notification of stories of interest
• Heterogeneity on the types of news
• News feeds, media outlets, press releases,
  announcements on websites, etc.

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Semantic needs

• Store all the data necessary for the use case
• Ontologies used for each news source
• Instance data extracted from the news sources
• Alignments between each news source ontology

Alignment repository
Data repository
Ontology repository
DATA METADATA MANAGEMENT
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Semantic needs

• User interface support for
• Formulating a query
• Displaying the results
• System-intern support for
• Formulating the query across the aligned instance
  data
• Extracting the results

Semantic query editor
QUERYING AND REASONING
Semantic query processor
Query answering
Alignment repository
Data repository
Ontology repository
DATA METADATA MANAGEMENT
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Semantic needs
ONTOLOGY ENGINEERING
Ontology learner
Ontology editor
Ontology browser

• Ontology creation
• Semi-automatic learning
• Manual enrichment

Ontology view customization
Semantic query editor
QUERYING AND REASONING
Semantic query processor
Query answering
Alignment repository
Data repository
Ontology repository
DATA METADATA MANAGEMENT
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Semantic needs
ONTOLOGY ENGINEERING
ONTOLOGY EVOLUTION
ONTOLOGY INSTANCE GENERATION
Automatic annotation
Ontology populator
Ontology versioner
Ontology learner
Ontology editor
Manual annotation
Ontology browser
Ontology view customization
Semantic query editor

• Ontologies will change over time
• Instance generation
• Semi-automatic annotation

QUERYING AND REASONING
Semantic query processor
Query answering
Alignment repository
Data repository
Ontology repository
DATA METADATA MANAGEMENT
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Semantic needs
ONTOLOGY ENGINEERING
ONTOLOGY EVOLUTION
ONTOLOGY INSTANCE GENERATION
Automatic annotation
Ontology populator
Ontology versioner
Ontology learner
Ontology matcher
Ontology editor
Manual annotation
Ontology browser
Ontology view customization
Semantic query editor

• Ontology alignment at run-time
• OR
• Mapping generation at design-time

QUERYING AND REASONING
Semantic query processor
Query answering
Alignment repository
Data repository
Ontology repository
DATA METADATA MANAGEMENT
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Index

• State of the Art
• Semantic Web Framework
• Components of the SWF
• Example use case
• Conclusions and next steps

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Conclusions

• SWF aims
• To help developers building SW applications
• To diminish development costs
• SWF describes
• Types of SW technologies
• Their functionalities
• Dependencies between technologies
• SWF supports the identification of
• Semantic components of SW applications
• Implementations of these components

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Next steps

• Reference architecture for building Semantic Web
  applications
• Components, interfaces and protocols

• Methodology for building large scale semantic
  applications
• Allow an easy, fast and reliable development and
  deployment of Semantic Web applications

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More information

• D1.2.5 Architecture of the Semantic Web Framework
  v2
• Publicly available in the Knowledge Web portal
• http//knowledgeweb.semanticweb.org/
• Contact us
• rgarcia_at_fi.upm.es
• omunoz_at_fi.upm.es

Thanks! Questions?
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Towards a component-based framework for
developing Semantic Web applications

• Raúl García-Castro, Asunción Gómez-Pérez, Óscar
  Muñoz-García , Lyndon Nixon
• rgarcia,asun,omunoz_at_fi.upm.es
• ASWC - Bangkok, Thailand
• 4 February 2009