RDF

Using RDF as a framework enables you to retain some of the structural information during the declaration.

RDF's properties make it easy to merge data and query across data from different sources.

With SPARQL, your coupling with data can be very abstract because of the distributed but interlinked nature of the RDF.

Defined as "a repository of RDF graphs managed by a single service" it serves as the endpoint to which any SPARQL statement will be posted.

These, unfortunately, are not as blithely accounted for as the fact that our earlier RDF examples did not use any defined classes.

There needs to be an automatic method to recognize the presence of RDFa content and extract the RDF out of it.

RDF is often used to represent semi-structured data.

Not the RSS that you're thinking about: this RSS stands for RDF Site Summary, and it defines a syndication format in a semantic manner.

The beauty about this is that you don't have to describe yourself , or the car model. The RDF application will sort it out for you .

Because SKOS is defined using the RDF model, it's easy to read and create data in an XML format.

Google seems to determine file type by file extension, only including files ending in . xml, . rdf and . rss.

All that WSDL provides could really have been written in the RDF Serialized format.

she was dressed in a haute couture dress that the girls and Claudia had made her buy for the RDF New Years Eve party.

If you expressed an author relationship in an RDF file on your site, could the computer assume they were the same thing?

Given the frequency with which this column focuses on RDF, it's worth noting the recent spate of activity on this W3C specification.

And information in these formats can be treated as RDF statements, allowing RDF to be used to integrate data from many sources.

RDF containers are used to describe group of things. For example, to list the authors of a book or to list the members in a band.

To a large extent, the actual implementation of provenance tracking depends on the underlying toolkit that you use to process RDF.

The result of the rdf. complete function call is a node set of Statement elements.

So far, in brief discussions of how one might use and query the Issue Tracker RDF metadata, we used a simple and primitive query API.

This is not a coincidence as the idea behind the RDF Site Syndication specification is to produce a syndicated format that is RDF compliant.

However, the RDF standard is now used as the standard to describe general information, resources, and relationships.

By using RDF files like this, my "Semantic Web Agent" can determine if I can trust the person I am dealing with.

The simple example demonstrated in this article only scratches the surface of provenance tracking with RDF.

Jena is engineered to work well with RDF data models, just as JDBC is suited for working with relational models.

RDF gives meaning to data through sets of "triples. " Each triple resembles the subject, verb and object of a sentence.

There is a more natural early entry for WSDL cataloging and discovery in the form of the Resource Description Framework (RDF).

Sesame is a library for Java programming language that enables you to store and manipulate RDF data using an SQL database.

All this data is published in the Resource Description Framework ( RDF) format.

Jenabean's primary advantage, as you've seen, is in bridging the gap between Java objects and RDF.

Therefore, any expression that returns a single resource (rdf: type) is converted to a list type with a single entry.

It also maintains a very thorough issue tracker, a growing set of test suites, and updated documents on the RDF model and syntax.

The online RDF Validator parses your RDF document, checks your syntax, and generates tabular and graphical views of your RDF document.

This difference is the result the graph-based nature of the RDF model.

RDF has no explicit ordering because the edges form a set, but XML elements do have ordering.

It is not very likely that you will be able to sell your car just by putting your RDF file on the Internet.

You can see that I used rdf: about in the service element to add a statement about the port I had previously described as its subject.

This philosophy already appears to be paying large dividends as RDF is undergoing a minor renaissance of activity and discussion.

A further goal is to wrap up the RDF schema specification, which is currently still in limbo as a candidate recommendation.

You'll see that the RDF output requires namespaces, and in many cases, those namespaces are repeated.

Depending on whom you ask, RSS stands for RDF Site Summary, Rich Site Summary, or other acronyms that are less tactful.

The machine-readable form uses RDF and thus makes available the network effects that have been covered throughout this column.

The Resource Description Framework (RDF) is a perfect way to describe objects while maintaining the meaning of that data.

The Ministry of Health has a policy to expand the RDF to the whole country and has already commenced roll-out to seven more states.

Versa focuses on the nodes and arcs in the RDF model rather than looking at the model as a collection of triples.

The complete method allows you to search the RDF model for statements that match a specified pattern.

In RDF, this triple would be encoded based on the format used to identify cartoon characters and their arch-enemies.

Whether RDF succeeds in this goal is up for debate, but RDF is well-known for its active community and broad range of tools.

I use RDF types that correspond to the WSDL element names for each of the resources used in the description.

An exhaustive analysis of RDF is beyond the scope of this article. However, see Resources for links to more information.

In particular, RDF is the most promising technology for describing relationships and data that must be indexed for Web services.

RDF is increasingly recognized as an excellent choice for representing and processing semi-structured data.

There is an RDF abbreviation that allows namespace-resolved attribute names to be treated as property names.

The DCMI specification is one of the most popular XML languages used with RDF.

The core of Versa is traversal expressions, which allows you to traverse the RDF graph.

When this is parsed into triples by an RDF processor, I obtain the data shown in Listing 2.

Resource Description Framework (RDF) is a model for describing collections of formalized statements about a Web resource.

This allows you to begin creating RDF quickly from the Java tier without much trouble.

Metadata about a particular LSID consists of a collection of RDF statements.

Let's take a look at the RDF version of the example in condensed form.

Future topics include exposing WordNet as an RDF database and using it to enhance searching.

As mentioned above, DOAP files that conform to the schema will lose some RDF expressivity, but for most people this loss will not matter.

Take a look all the way back to the sample RDF document in Listing 1.

These changes basically take a section of the description and encode it into RDF serialization.

This article examines ways that SOAP can be used to communicate information in RDF models.

OWL and RDF are much of the same thing, but OWL is a stronger language with greater machine interpretability than RDF.

The ccREL is a specification describing how license information may be described using RDF and RDFa and may be attached to works.

Applications can be loosely coupled to multiple RDF data sources over the Web.

RDF serves as the foundation upon which the Semantic Web is built: it is a standard to represent data as a directed, labeled graph.

RDF has always allowed users to specify the language used to express the values of properties.

To organize the information, the resource description framework (RDF) data about an entity are partitioned into different concept spaces.

Mozilla also uses Resource Description Framework (RDF) to manage semi-structured data used in XUL.

RDF is another W3C-approved standard, and is a standard for the definition of the information and resources.

RDF collections are used to describe group that contains ONLY the specified members.

As an illustration, let's look at the sample RDF issue tracker instance from the last installment, repeated here in Listing 1.

RDFa is a standard way of encoding the Resource Description Framework (RDF) model into structured documents.

One way to get the best of both worlds is to use GRDDL, a system for viewing XML through an RDF lens.

eRDF seeks to scale beyond a small set of formats and vocabularies by using namespaces and the arbitrary RDF graph data model.

I left the types element out of the RDF section.

The core Semantic Web technology is RDF, a W3C standard that reduces all data to three-part statements known as triples.

This article thus closes the loop by presenting an RDF representation of the XML WordNet system I have presented so far.

However, to convert existing data to RDF is a huge and expensive task, and is unnecessary in many cases.

This would mean that we could never reliably compare what we stored in the RDF model with any other data.

Wife Swap is a reality television programme, produced by UK independent TV production company RDF Media and created by Stephen Lambert.

Instead, I think the RDF working group chose the right course in developing a simple and strictly-defined textual format for RDF graphs.

You then use the content of these classes to produce the RDF document.

Publication and subscription was represented as resource description framework(RDF) graph and RDF graph patterns.

Our online software repository service has a schema loosely based around the RDF schema in RPMFind. net.

Some of the media conventions for CC licenses rely on links to the RDF version of the licenses.

This stylesheet scrapes the page for implicit metadata, which it then presents in Resource Description Framework (RDF) format.

You can use data in other formats and create RDF data from it, which will be bound to XUL elements.

In this case, the requirement is to translate the Twitter public timeline in Atom format to RDF Site Syndication format.

Declaration, and that all RDF processors for which interoperability is needed support XML base.

In effect, this traversal expression returns the objects of all statements with an rdf: type predicate.

Typed node indicates that the resource being described is the very document in which the RDF is embedded.

Again, sometimes RDF is a good model for processing, but not the most practical syntax or even storage form for universal DBMS.

The basic approaches explained here will be a useful starting point when employing RDF models in your own Java applications.

The core standards are RDF for representation, SPARQL for querying, RDFS for structuring, and OWL for structuring and reasoning.

The W3C RDF standard lets you assign metadata to anything that you can identify with a URL.

Your driver's license would be analogous to an RDF XML file that describes you.

RDF models can be merged together easily, and serialized RDF can be simply exchanged over HTTP.

Let's start with the basics: creating a model from scratch and adding RDF statements to it.

Jena provides an API for writing and reading RDF, which can be stored and persisted in various ways.

RDF is a recognized format for the distribution of metadata information in existing situations.

Ontology can be used to describe the semantics of XML data, HTML page with RDF.

rdfs . Then, automatic reasoning with RDF and RDFS becomes possible, even though a first-order logic proof system is required.

The discovery mechanism is a sounder implementation, using HTML links or HTTP headers rather than embedded RDF.

Tools that are RDF-schema- or OWL-enabled can use the schema to assist authoring or interpretation of DOAP descriptions.

Embedded RDF is a technique for embedding RDF data within XHTML documents using existing elements and attributes.

RDF uses URIs as identifiers, but you want the database to retrieve human-readable film titles.

The RDF representation I give in this article is still useful because it provides one concrete RDF model of the meta-data encoded in WSDL.

The objects in RDF are either URIs (in which case you can use LSIDs) or so-called "literal" values that may or may not be typed.

RDFa is a standard convention for expressing structured metadata as RDF statements within HTML elements.

Of course in RDF all subjects and predicates are URIs, but objects can be URIs or literals.

Versa is an open RDF query language based on the typical needs of a developer for RDF tools that can be used within other applications.

Thus, it is a simple matter to use any particular RDF syntax extracted from the WSDL to construct the same model.

The Redland RDF application framework is a toolkit that's definitely worth further investigation.

IMDL uses RDF as information exchange format, and implements protocol translation, query translation and result integration.

It is not as expressive right now as RDF and OWL, but it is very compact and uses available XHTML facilities to add semantics to the pages.

Extract the extension directory and change the contents of the install. rdf file, as shown below.

The same SPARQL queries can include content contributed by relational databases, REST services, native RDF triplestores and now documents.

Finally, RDF is a data model that does not include a standard serialization.

Java programmers will increasingly benefit from having the skills to work with RDF models.

OWL comes with a larger vocabulary and stronger syntax than RDF.

RDF binding tools must let you arbitrarily relate a JavaBean property to an RDF property URI (assuming they are type compatible).

The HTML code generated by the license is not pretty, although it is easier to modify than the RDF version in the XML syntax.

After all, RDF is merely URIs, links, and labels, so any model that includes these three can readily work with RDF systems.

Dave Beckett maintains an exhaustive collection of semantic Web and RDF links on his.

You must start with a base RDF definition and customize it to your needs.

To fully embrace the Semantic Web idea, you can apply traditional Web-development techniques to RDF data using SPARQL.

The Resource Description Framework (RDF) is the workhorse of the Semantic Web.

Embedded RDF is not currently developed by a standards body.

You can obtain the WordNet RDF representation used in this article from.

This site is a searchable directory and chronicle of Semantic Web schemata, which you can access with RDF query.

You should also remember that the components of an RDF triple are usually URIs.

In RDF, ordering of child nodes is undefined, so you can't assume that Jena will retrieve the list of friends in any particular order.

I used every RDF serialization trick available to minimize the changes from the original XML structure.

The SPARQL Protocol And RDF Query Language (SPARQL) is currently under discussion as a W3C Working Draft.

An example of what an issue looks like in RDF serialization is shown in Listing 1.

It stores data in RDF (an XML-like semi-structured representation) and uses a custom in-memory database system.

Using the RDF producting technics and choosing interrelated parameters properly, high quality RDF can be acquired.

Another property literals can have -- and one introduced more recently in RDF -- is a data type.

Once the model has been created, the WordNet RDF documents can be read in from the filesystem.

Therefore, it's helpful if the DOAP viewer is an RDF-aware application.

In the world of OWL and RDF, relationships of various cardinalities are expressed through multiple assertions of the same property.

The RDF statements you intend the file to assert may depend on the context of the file itself.

We will use the extension function rdf. complete in our stylesheet to gather information about all of the software in the system.

rdf: type is an RDF property that ties an individual to a class of which it is a member.

LOD supports RDF as a conceptual model, but the new emphasis is more on linking and openness than on any one syntax.

RDF Site Summary (RSS) is a generic XML-based format for delivering and aggregating web content.

The interesting work of fetching and storing the RDF data happens in the Aggregator class.

Any RDF application that knew how to handle Dublin Core could then make at least basic use of DOAP data.

The basis of this data in RDF gives the service some unique advantages.

Together with RDF Schema, OWL provides a mechanism to formally describe the content of RDF models.

In the section that was converted to RDF, the most noticeable change is the addition of rdf: ID attributes to the core WSDL elements.

RDF query language. He is a computer engineer and writer born in Nigeria, living and working in Boulder, Colorado, USA.

Another key information file for XPI is install. rdf, Listing 5, which contains instructions for installing the extension.

The RDF data is sorted, cross-referenced, and converted to XML by a SPARQL engine.

The category and manufacture of refuse derived fuel (RDF) are briefly introduced.

But an RDF expresses that relationship in only one way, so it becomes feasible to build generic parsers.

Jenabean also has support for binding to a SPARQL (SPARQL Query Language for RDF) result.

RDF Primer: This Primer provides the basic knowledge required to effectively use RDF.

In the bloggers. rdf model, contributor will match the foaf: Agent blank-node at the top of Figure 1.

Again, just like relational database management systems (RDBMS), objects and RDF are similar in some ways and different in others.

I have found that it makes sense to persist any variable with a global scope in the RDF store.

It also describes the content and purpose of other RDF specification documents.

Moving beyond these ad-hoc methods, XHTML 2. 0 introduces a method for the specification of RDF-like metadata within a document.

This is an important principle for serializing RDF models for SOAP transmission: to avoid in-line declarations.

Takes the URL of the blog list as its argument and parses it into the RDF model.

The Revolving Drug Fund (RDF) was established in 1989 to facilitate access to medicines in health facilities in Khartoum state.

RDF is the main format used in the LOD community.

This is another example of taking advantage of the flexibility of RDF syntax to minimize mutation from the original WSDL.

And the fact that the SPARQL query language has come out now means that all kinds of data can be surfaced as RDF.

An RDF list containing the members of an ordered collection.

Not surprisingly, Planet RDF is built using XML and RDF technology throughout.

The simplest approach is simply to make the rdf: RDF element the single top-level element of the SOAP body, as illustrated in Listing 6.

Discusses the flexibility of representing data as RDF graphs instead of in database tables and XML documents.

Cyclic relationships are a common situation in RDF and in object models.

Some syndicators use this capability to add information using Resource Definition Format (RDF).

If you look at my description in Listings 1 and 2, you will notice my use of the dc: subject property with the simple values XML and RDF.

There is no official RDF encoding for SOAP yet, but this discussion is based on the conventions and prescriptions of RDF and SOAP.

An essay that explains the advantages of RDF for expressing XML vocabularies.

Unfortunately, perhaps because the main XML expression of RDF looked unnecessarily complex, uptake was slow.

One nice feature of RDF schemas is that if you use them properly, you can transform them into a good source of documentation.

It executes a query against bloggers. rdf and outputs the results to the console.

One thing WSDL leaves unmentioned is its potential for integration with RDF.

The RDF Schema class and property system is similar to the type systems of object-oriented programming languages such as the Java language.

You added the namespace "contact" linked to the RDF VCard vocabulary.

It contains key metadata about the software package, including author, version, and description, in the RDF format (see Listing 1).

Compare the different ways of expressing a simple relationship in XML given in Listing 1 with the RDF triple in Listing 2.

You can see where the references to these identified resources are made by using the rdf: resource attribute.

This presents a thorny choice - whether to choose an RDF or XML representation.

The structure of an LDAP directory lends itself very nicely to transformation into RDF.

I'm leaving out the outer RDF envelope to save space.

Access that URL, then paste the contents of twitter. rdf into the text area.

And, guess what: That predefined format is accomplished using RDF.

Listing 4 shows the contact information with additional markup required for the RDF vCard.

If we ran this query on this model, we would get a list of resources (because the objects of rdf: type statements are resources).

RDF-aware software written to the Listing 1 format will just ignore the extra homepage and image properties.

How is RDF information created, accessed, and processed?

4SS automatically creates RDF statements linking documents to their document definition.

An RDF triple has three components: a subject, a predicate (or verb), and object.

The interesting work of fetching and storing the RDF data happens in the.

Fortunately, you can use RDF to provide more information about the linked resource.

What if you instead had a writer relationship in your RDF triple?

This code's advantage is that it maps directly to RDF concepts in a transparent and explicit way.

This generated RDF document is web addressable at the URL above.

That's not enough, however, and you must resort to RDF processing to perform the remaining steps of the validation.

The nice thing about programming at the RDF level is that you can just say, I'll ask for all the books.

RDF is simply a formal way of encoding such information.

I'll present corresponding updates to the instance RDF below.

I showed you how to use an RDF-based WordNet database to add some natural language power to application-specific search engines.

Listing 1: What the WSDL description of snow boarding endorsement search would have looked like in valid RDF syntax.

In effect, this is a query consisting of an RDF object with the properties as query parameters.

The binding tool must prevent loading the full RDF model into memory as JavaBeans but also allow for this as a feature when necessary.

Both RDF and SPARQL are technologies within what has been dubbed the Semantic Web stack.

Column in the IBM developerWorks XML zone for on-going discussion of RDF and other XML technologies related to knowledge management.

This wraps up my three-part discussion of how to use the WordNet natural language semantic database in XML and RDF applications.

The extension function calls the complete method on the RDF model.

To record this information, I need some way to associate that information with the RDF statements I've found.

Perhaps this would query the RDF model when index. html is requested.

It introduces the basic concepts of RDF and describes its XML syntax.

As mentioned before, CONSTRUCT queries are quite important, especially for data that is not natively stored in RDF.

Default 3D far-field calculations now also lists radiation-efficiency and RDF value.

Typed node in the RDF as shown in Listing 2.

It offers very high semantic transparency, but support for RDF is not yet as widespread as support for XML.

RDF defines a directed graph of relationships.

The vCard RDF schema is more general in coverage than the FOAF schema, but we don't need its additional properties.

RDF literals can be given data types such as "integer" , "string" , "date" , or even "morse code" .

You will learn how to build and interpret RDF information in both its familiar XML form and its non-XML shorthand form.

In the world of RDF, it's advisable to use common properties; otherwise, a Semantic Web will never develop.

Project is a Python-based framework for RDF servers.

This graph is typically expressed in RDF triples.

RDF is a language for presenting information to the World Wide Web.

This element provides a list of all document links contained in the RDF file.

Now comes the hard part: deciding which RDF schema to adopt.

Columns, which cover RDF and other technologies in greater depth.

At first glance, RDF data looks a little bit cumbersome and quite verbose.

This is a common approach to representing queries in RDF, although it gets unwieldy as queries get more complex.

To avoid any potential for error, you should always represent LSIDs in RDF using their canonical form: lower case.

According to the conventional drawing of RDF models, this means it returns all ovals and arcs (but not rectangles).

A vertical schema is also closer to semantic Web standards like RDF.

We can use RDF's open, extensible data model to accumulate the facts from different encodings into the same output model.

You can actually use this RDF description to write a flexible driver for dispatch code.

Links and aggregates FOAF and RDF content.

The idea is that you run an existing XHTML document through an XSL transform to generate RDF.

Probably the most common place you will find DCMI terms is embedded in RDF.

This policy is based on the experience of the RDF within Khartoum state.

RDF was designed to provide a common way to describe information so it can be read and understood by computer applications.

You can also generate a similar graph using Dan Brickley's on-line RDF visualizer.