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Foundations V: Infrastructure and Architecture, Middleware

Deborah McGuinness and Peter Fox

CSCI-6962-01

Week 9, October 27, 2008

Contents• Review of reading, questions, comments

• Technology and how to use it

• Summary

• Next week

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Semantic Web Methodology and Technology Development Process

• Establish and improve a well-defined methodology vision for Semantic Technology based application development

• Leverage controlled vocabularies, et c.

Use Case

Small Team, mixed skills

Analysis

Adopt Technology Approach

Leverage Technology Infrastructur

e

Rapid PrototypeOpen World:

Evolve, Iterate, Redesign, Redeploy

Use Tools

Science/Expert Review & Iteration

Develop model/

ontology

EvaluationEvaluation

Architecture• Importance of state

– Grids– Web

• Existing infrastructure– Catalogs– Data sources– User interfaces– Services

• Wrapping these syntactic interface

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Inventory• Refer to the Resources

– Files– Databases– Catalogs– Existing UI– Services– User database/ security– Logging– Backup/ archive

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… … … …

Geo App1Geo App2

App3

DB2 DB3DBn

DB1

WSCommon

Web Coverage Service

Web Feature Service

Web Mapping Service

Limited interoperability

Fox WHOI: Semantic Data Frameworks March 20, 2008

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The Astronomy approach; data-types as a service

… … … …

VO App1

VO App2VO App3

DB2 DB3DBn

DB1

VOTable

Simple Image

Access Protocol

Simple Spectrum

Access Protocol

Simple Time

Access Protocol

VO layer

Limited interoperability

Lightweight semantics

Limited meaning, hard coded

Limited extensibility

Under review

… … … …

Web Portal

Web Serv.

API

DB2 DB3DB…

DB1

Semantic mediation layer: Ontology - capturing concepts of Parameters, Instruments, Date/Time, Space, Event, Feature, Data Product (and associated classes, properties) and Service Classes. Maps queries to underlying data. Generates access requests for metadata, data. Allows queries, reasoning, analysis, new hypothesis generation, testing, explanation, etc.

Semantic mediation layer - mid-upper-level

Education, clearinghouses, other services, disciplines, etc.

Metadata, schema, data

Query, access and use of data

Semantic interoperability

Data as Service

Implementing• Let’s take an example

– VSTO– Representative but does not exercise all

semantic web capabilities

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Fox RPI: Semantic Data Frameworks May 14, 2008

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Web Service

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Additional middleware• Web server, Tomcat are essential (Axis)

• MySQL (or similar) is very handy to have

• OPeNDAP – for data access and transport

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Fox RPI: Semantic Data Frameworks May 14, 2008

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Web Service

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Infrastructure• Protégé-OWL-API

– http://protege.stanford.edu/plugins/owl/api/index.html

– http://protege.stanford.edu/plugins/owl/api/guide.html

• Jena (Java API for RDF and OWL)– http://protege.stanford.edu/plugins/owl/jena-

integration.html

– http://jena.sourceforge.net/

– Migrate to other triple stores when needed

Using Protégé• Load VSTO into Protégé 3.4beta

• Generate Java-OWL classes from Tool menu

• Review other tools for generating code stubs

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Examine some of the code• Java Factory class

• Code stubs and ‘myclass’

• VSTO code base will be made available for browsing

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Jena

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Infrastructure• Reasoner – DIG/Pellet

– http://protegewiki.stanford.edu/index.php/ProtegeReasonerAPI

• SPARQL– http://www.w3.org/2001/sw/DataAccess/tests/

implementations

• Spring (Application Framework - optional)– http://www.springframework.org/

• Eclipse (IDE)– http://www.eclipse.org/

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Infrastructure• Rules

– SWRL – plug-in for Protégé– Jess rules– Jess rules engine -

http://herzberg.ca.sandia.gov/jess/

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Software development• Junit (generated in Eclipse)

– http://smi-protege.stanford.edu/repos/protege/owl/trunk/junit.properties.template

• Faceted browsing – mspace

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Metadata• Migrate metadata into ontologies – instances,

choose how you will populate them– Manual – okay to start with sufficient annotation– Scripted – preferred – rdfs_comment: essential

• Choose what you will not, cannot move

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Services• If you are going to put up services, include an

end-point and a link to your WSDL (or SAWSDL)

• At this point, developing a full services ontology, e.g. in OWL-S may be beyond the initial implementation

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Fox RPI: Semantic Data Frameworks May 14, 2008

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Semantic Web Services

Fox RPI: Semantic Data Frameworks May 14, 2008

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Semantic Web Services

OWL document returned using VSTO ontology - can be used both syntactically or semantically

Result/ outcome• Refer to the use case document

• Check the expected outcome and see if the test (to verify outcome) is complete

• Document all variations, note alternate flows

• Document in sufficient detail that someone else could come along and re-produce your work

• Include URLs for access, etc.

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Metrics• Next week we will cover evaluation but

already be thinking of things you can measure– Could not do before– Faster, more complete, less mistakes, etc.– Wider range of users

• Estimate the baseline before you start

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Summary• Architectural design needs to take into

account existing resources that you will leverage

• Keeping it simple is also very important as you begin to implement

• Take time to learn the tools and the supporting APIs; look at existing examples and working code

• Being prepared to iterate is really essential

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Next week• This weeks assignment:

– Reading: Evaluation– Assignment 3: Team Use Case Implementation

(on the class wiki later today)

• Next class (week 10 – November 3): – Class Presentation II: Use Case Implementation

• Office hours this week – Thursday afternoon 1-2, Winslow 1140

• Questions?

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