3kbo

The freely available PricewaterhouseCoopers Spring 2009 Technology Forecast explains the value of the Semantic Web and Linked Data in the context of Enterprise applications, presenting interviews with leaders in the field and outlining how CIOs and individual departments can introduce Semantic Web technologies into their organizations.

Forecasts include:

• “During the next three to five years, we forecast a transformation of the enterprise data management function driven by explicit engagement with data semantics” and
• “PricewaterhouseCoopers believes a Web of data will develop that fully augments the document Web of today”.

W3C standards providing the foundation for this Web of data include URIs, RDF, RDF Schema (RDFS), the Web Ontology Language (OWL) and the Semantic Protocol and RDF Query Language (SPARQL).

“URIs are more specific in a Semantic Web context than URLs, often including a hash that points to a thing such as an individual musician, a song of hers, or the label she records for within a page, rather than just the page itself.”

“RDF takes the data elements identified by URIs and makes statements about the relationship of one element to another.”

Each statement is a triple, a subject-predicate-object combination.

Ontologies (based on RDFS and OWL) describe the characteristics of these RDF data elements and their relationships within specific domains, facilitating machine interpretability of the data content.

“In this universe of nouns and verbs, the verbs articulate the connections, or relationships, between nouns. Each noun then connects as a node in a networked structure, one that scales easily because of the simplicity and uniformity of its Web-like connections.”

The Web of data approach clearly benefits a company such as the British Broadcasting Corporation (BBC) which “links to URIs at DBpedia.org, a version of the structured information on Wikipedia, to enrich sites such as its music site (http://www.bbc.co.uk/music/)”. It also links MusicBrainz for information about artists and recording.

As described by Tom Scott of BBC Earth:

“The relationship between the BBC content, the DBpedia content, and MusicBrainz is no more than URIs. We just have links between these things, and we have an ontology that describes how this stuff maps together.”

Other reviews of the PricewaterhouseCoopers Spring 2009 Technology Forecast include:

• Enterprises, Struggling to Manage Your Data? Try The Semantic Web
• PWC report on Semantic Web
• Semantic Web and Enterprise: PricewaterhouseCooper’s call to a Linked Data future

Tom Scott has a presentation on Linking bbc.co.uk to the Linked Data cloud and the article  DBpedia Examples using Linked Data and Sparql provides a simple example of using SPARQL to query Dbpedia.

“FOAF+SSL is an authentication and authorization protocol that links a Web ID to a public key, thereby enabling a global, decentralized/distributed, and open yet secure social network.”

In my case my FOAF file http://www.3kbo.com/people/richard.hancock/foaf.rdf#i is my Web ID.

A site using FOAF+SSL is Shout Box. Once a user has logged in to Shout Box and left a comment Shout Box displays the users Web ID along side their comment.

A user logging in to Shout Box identifies themselves with a certificate stored in their browser. If a user has more than one certificate installed they can choose from the list of certificates presented by the browser certifcate manager (shown below for Firefox).

Selecting a certificate for a FOAF+SSL login is simpler and quicker than typing a user name and password.

The two obvious things are user needs in order to login with FOAF+SSL are:

• an X509 certificate and
• a Web ID (FOAF file).

FOAF+SSL also requires:

• A reference to the Web ID from the certificate. This is provided by setting the Web ID as the value for  “X509v3 Subject Alternative Name”.
• The public key of the certificate published in the Web ID (FOAF file).

If the key published in the Web ID matches that contained in the certificate then the server can conclude that the person logging in is the owner of the Web ID (FOAF file).

I can check the details of the certificate I have been using and see the reference to my Web ID by first opening the Firefox Certificate Manager (by pasting chrome://pippki/content/certManager.xul into the brower location bar). The Certificate Manager lists all the installed certificates.

To see more information about this certificate I select it then click “View …” to get a dialog box with two tabs “General” and “Details”.  Selecting the “Details” tab and “Certificate Subject Alt Name” shows that my Web ID, http://www.3kbo.com/people/richard.hancock/foaf.rdf#i is the value set for the “X509v3 Subject Alternative Name.

An easy way to create an X509 certificate with a reference to a Web ID is to follow the steps outlined in Henry Storys article creating a foaf+ssl cert in a few clicks. I used this process to create the other two certificates shown above.

I created my main X509 certificate by following the steps outlined by Henry in his earlier article foaf+ssl: a first implementation. This gives a good programmatic understanding of what’s happening.

( The code is under activate development so if you try it and have problems then check out revision 468 to get the code that matches the article i.e. svn checkout https://sommer.dev.java.net/svn/sommer/trunk sommer-r468 –username guest -r 468 )

Using this approach the main tasks for setting up a user with FOAF+SSL are:

• Running GenerateKey to create an X509 certificate , setting an existing FOAF file as the Web ID.
• Adding the RDF statements defining the public key to the FOAF file.
• Adding the X509 certificate to the users browser.

GenerateKey generates the RDF statements defining the public key in N3 format. If your FOAF file is in RDF/XML format like mine then you need to convert from N3 to the RDF/XML.

Adding the following worked for me:

<rsa:RSAPublicKey>
<cert:identity rdf:resource=“#i”/>
<rsa:public_exponent cert:decimal=“65537″/>
<rsa:modulus cert:hex=“d258d85da71a4f1199cae5e8e18a5ffa9127d9796526299b746de9fdcbc1364e074dc143d0ebbd3d3890d7e95b8b4931e3798a7a8f8dbd3441927b6601fb504ca2a919a803e31a6112fea227102dc1424946fb92f8f651f3da855ec43e496f8e0098b596f33af80e7b86d831d46948e040a656f3f00a67b724ccfb55fa4660d3″ />
</rsa:RSAPublicKey>

Tried out the newly released GoodRelations Annotator to create a Semantic Web description of a business.

The GoodRelations Annotator is an online form-based tool that creates an RDF/XML file “semanticweb.rdf” containing a description of the key aspects of the business. The description is based on concepts defined in the GoodRelations OWL ontology. In particular the description contains a BusinessEntity representing the business and one or more Offerings. Each Offering describes the intent to provide a Business Function for a certain Product or Service to a specified target audience.

The generated RDF/XML file can be either be published directly on the company’s Web site or used as a skeleton for developing a more fine-grained description.

The link Publishing GoodRelations Data on the Web provides guidelines on publishing to the web.

In my case I created a description for my embryonic business 3kbo.

I’m interested in linking the generated semanticweb.rdf to other things, in particular linking the BusinessEntity with people and with other BusinessEntitys.

Initially I added the URI of my foaf file to the BusinessEntity instance using rdfs:seeAlso, but after reading the definition of BusinessEntity i.e. that it represents the legal agent making a particular offering and
can be a legal body or a person, I changed it to owl:sameAs.

E.g.

<gr:BusinessEntity rdf:ID=”BusinessEntity”>
…
<owl:sameAs
rdf:resource=”http://www.3kbo.com/people/richard.hancock/foaf.rdf#i“/>
…
</gr:BusinessEntity>

This makes sense for my simple case, since as a sole trader I am the BusinessEntity. When viewed in Firefox using the Tabulator Extension owl:sameAs also provides an inferred link from my foaf file to my semanticweb.rdf as shown below.

A part of the business description I don’t understand yet is how best to use the eClassOWL ontology to describe the Product or Service.

For example using the GoodRelations Annotator I selected “19 information, communication and media technology” as the Category and “1904 Software” as the Group.

This leads to http://www.ebusiness-unibw.org/ontologies/eclass/5.1.4/#C_AKJ317003-tax being used in the definition of the product or service, i.e.

<gr:typeOfGood>
<gr:ProductOrServicesSomeInstancesPlaceholder rdf:ID=“ProductOrServicesSomeInstancesPlaceholder_1″>
<rdf:type rdf:resource=”"&eco;#C_AKJ317003-tax”>
…
<gr:ProductOrServicesSomeInstancesPlaceholder>
<gr:typeOfGood>

Because of the size of the eClassOWL ontology it takes awhile to dereference this link. It would be good to be able to provide a  more user friendly reference at this point that provided a description of the product or service.

Beyond this simple example I am interested in semantic web descriptions of other more complex relationships between a BusinessEntity (when not a person) and the people involved with the business (e.g. directors, CEO etc …) and between other BusinessEntitys.

Potentially GoodRelations and eClassOWL could be used as part of an Enterprise Architecture describing the who, what, how, when, where and why of a business.

A list of the maven commands and references I commonly use.

Creating Maven Projects

• mvn archetype:create -DgroupId=com._3kbo -DartifactId=application (create a project for building a jar file )
• mvn archetype:create -DgroupId=com._3kbo -DartifactId=webapplication -DarchetypeArtifactId=maven-archetype-webapp (create a web app project for building a war file)
• mvn archetype:generate (Select the number of the desired archetype.)

Building, Testing, Packaging and Installing to the Repository

• mvn clean            (cleans the project, i.e. delete the target directory)
• mvn compile        (compiles the source code)
• mvn test              (if required compiles the source code, then runs the unit tests)
• mvn package       (compiles, tests then packages the jar or war file)
• mvn clean install  (cleans the project, compiles, tests, packages and installs the jar or war file)
• mvn install           (compiles, tests, packages and installs the jar or war file)
• mvn -o install      (compiles, tests, packages and installs the jar or war file in offline mode)
• mvn -Dmaven.test.skip package       (package without running the tests)
• mvn -Dmaven.test.skip clean install  (clean and install without running tests)
• mvn -o test         (test offline)

Unit Tests

• mvn test –Dtest=AspectTest (run a specific test)
• mvn test -Dtest=*ModelTest (run a subset of tests using regular expression. E.g. test all ModelTest classes)

Excluding log4j.properties from jar file

Move log4j.properties from src/main/resources to src/test/resources.
That way it gets picked up by the testResources for testing but excluded from the jar file.

Manually Install a file to the Repository

mvn install:install-file -DgroupId=com._3kbo -DartifactId=model -Dversion=1.0.0 -Dpackaging=jar -Dfile=new_file.jar

Set Java Build Version

<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
</plugins>
</build>

Documentation

The mvn site command builds a useful dependency tree at target/site/dependencies.html.

• mvn site (generate documentation in the target/site directory)
• mvn javadoc:javadoc (generate javadoc in target/site/apidocs directory )

• mvn help:active-profiles (lists the profiles currently active)
• mvn help:effective-pom (displays the effective POM for the current build)
• mvn help:effective-settings (displays the calculated settings for the project, given any profile enhancement and the inheritance of the global settings into the user-level settings.)
• mvn help:describe (describes the attributes of a plugin)

For large projects mvn site can run out of memory. Use MAVEN_OPTS in the mvn or mvn.bat script to allocate additional memory, e.g:

MAVEN_OPTS=”-Xmx512m -Xms256m -XX:MaxPermSize=128m”

Repositories

Jena http://jena.hpl.hp.com/repo
Jersey http://download.java.net/maven/2/
Maven Central http://www.ibiblio.org/maven2

References

Maven Home
Maven: The Definitive Guide
Better Builds with Maven
Maven Lifecycle

Stored in relational database tables within CDMS is a subset of information that could usefully be shared with the general building, civil engineering and construction industry to help promote a higher, uniform standard of quality.

This subset is described in more detail in the article Constructing an Ontology - Common Inspection and Test Plans.

The central concept is an Inspection and Test Plan (ITP) that identifies the points in a construction project when work of a specific type will be inspected and verified that it meets acceptance criteria.

An elegant way to share the Inspection and Test Plans is to publish them on the Semantic Web as an OWL ontology. The preferred way to doing this is to publish the Inspection and Test Plans as Linked Data, following the patterns outlined in the tutorial on How to publish Linked Data on the Web.

Once published as Linked Data the Inspection Test and Plans can be used by other building applications.

The process for doing this is to create  an owl:ObjectProperty such as the following appliesInspectionTestPlan and add it to the OWL definition of a building project.

building:appliesInspectionTestPlan
a       owl:ObjectProperty ;
rdfs:domain building:BuildingProject ;
rdfs:label “applies inspection test plan”^^xsd:string .

The  example building project  http://3kbo.com/examples/building4.rdf contains appliesInspectionTestPlan and applies it to the Breaker Bay building project as shown in the image below.

In the example the Inspection and Test Plan referenced is contained in a data extract published at http://3kbo.com/examples/common_itps.rdf.

The D2R Server provides an easy way to publish the actual relational database tables containing the Common Inspection and Test Plans to the Semantic Web using the patterns outlined in the tutorial on How to publish Linked Data on the Web.

The Common Inspection and Test Plans are held in a MySQL database which was created by running the command:

mysql> create database common_itps character set utf8 ;

The D2R Server is installed by following the Quick Start instructions and adding the MySQL driver JAR file to the D2R Server installation /lib directory.

The mapping file was created by running the command

./generate-mapping -o mapping_common_itps.n3 -u db-user -p db-password jdbc:mysql://localhost/common_itps

and customized by removing some unnecessary database columns from the mapping file.

Also the following was added to the mapping file to explicitly define the server host and port.

@prefix d2r: <http://sites.wiwiss.fu-berlin.de/suhl/bizer/d2r-server/config.rdf#> .

<> a d2r:Server;
rdfs:label “D2R Server”;
d2r:baseURI <http://abeserver.isa.net.au:2020/>;
d2r:port 2020;
d2r:documentMetadata [
rdfs:comment "The Common Inspection and Test Plans are currently published as an experimental version. The data needs to be rationalized and the model confirmed before progressing to a draft status.";
];
.

Once the mapping file  has been generated and customized the server is started with the command:

nohup ./d2r-server mapping_common_itps.n3 &

An experimental verison of the “Common Inspection and Test Plans” can now be browsed online at http://abeserver.isa.net.au:2020/ in a web browser, ideally using Firefox with the Tabulator extension install.

Individual Inspection Test Plans can be opened directly in the browser using URLs such as http://abeserver.isa.net.au:2020/resource/inspection_test_plan/1.

Via content negotiation this request is redirected to the browser friendly page

http://abeserver.isa.net.au:2020/page/inspection_test_plan/1

The acutal RDF can be viewed directly at http://abeserver.isa.net.au:2020/data/inspection_test_plan/1.

SPARQL queries can be run using the AJAX-based SPARQL explorer http://abeserver.isa.net.au:2020/snorql/.