Sean Michael Kerner
SemanticWeb.com Contributor

There are a lot of different ways to connect the dots of content and data that comprise the Web. Two of them are microformats (define) and the GRDDL (Gleaning Resource Descriptions from Dialects of Languages) Semantic Web construct.

Both approaches have attempted to make sense of content by making use of metadata descriptors, but they differ somewhat. The World Wide Web Consortium (W3C) is trying to change that.

“Microformats and the Semantic Web always had a lot in common at a high level, but GRDDL fills in a few technical details so that they interoperate at a practical, running-code level,” Dan Connolly, the W3C GRDDL Working Group staff contact, told InternetNews.com.

While microformats use XHTML and HTML, GRDDL (pronounced “griddle”) extracts RDF (Resource Description Framework) data from XML so that it can be transformed or understood by other applications in a mashup or other application settings.

The way that GRDDL will work with microformats will require some effort from microformat authors.

“Microformat authors that want their data to integrate seamlessly with other semantic Web data should use well-formed XHTML and profile URIs,” Connolly explained. “For example, the dbpedia project takes millions of facts from Wikipedia and exports them using URIs and RDF and SPARQL.”

Connolly explained that the HTML specification lets authors use any name they like for conventions for class, as well as rel attribute values for styling and other processing. The conventional microformat names are hcard, hcalendar, summary and description, among others.

HTML has a special “profile” hook to use a URI to take those document-local conventions and share them in the Web. Some microformat documents use the profile hook, but not all do.

GRDDL links the profile documents to XSLT transformations that allow machines to exploit microformats and other syntax conventions.

The GRDDL specification has been under review for nearly a year. Connolly noted that early adopters have been participating in working out the kinks and finishing the test suite.

“At this point, the design has been through the entire W3C process, and it is stable and ready for widespread deployment,” Connolly said.

So what’s next for GRDDL?

“What’s next is to tweak flight itineraries and soccer schedules so that I can stop copying them by hand, one field a time, and start letting the computer manage the data for me,” Connolly said. “That’s what GRDDL and microformats and RDF and URIs are all about.”

Jennifer Zaino
SemanticWeb.com Contributor

Oracle is pushing hard on the application of semantic technologies to enterprise business problems. bITa Planet recently caught up with Robert Shimp, vice president of Oracle’s global technology business unit, to discuss what problems Oracle believes semantic technologies can solve for customers — and how.

bITa Planet: How does Oracle support semantic technologies?

Shimp:

Today we not only support the core data standards for the semantic web inside our database, but our application integration architecture, or AIA, offering uses semantic technology. We are already shipping that capability today as an integration capability for our applications. You’ll see more and more semantic technologies weaving its way into products as we go along.

We have a fundamental advantage in that with enterprise applications, you know an awful lot about the business process going on, the people that are using it, and so on, and that means the application can have a lot of metadata that it knows about what’s going on. The fact that we can store that metadata inside the database means we can provide far richer transactions and business processes for customers. It’s that ability to provide both the applications and the database that gives us that advantage.

How did Oracle get out in front on the semantic technology?

Oracle is the leading supplier of database technology for geographic information systems. We’ve been doing that for at least a decade or more. It turns out that maps or geographic information systems use a mathematical model called a network model. In other words, basically a map is all about different points and locations and the distance between points. It turns out that semantic technology uses exactly the same mathematical model to represent the links between concepts and ideas. So as we developed GIS technology over the years, it was relatively easy for the same development team to supply this same technology for semantic technology purposes.

Among the first companies Oracle worked with that were interested in applying semantic technologies to their business problems were those in the pharmaceuticals industry and government. How is the make-up of companies interested in this changing?

We’re now seeing lots of customers in different areas – financial services, pharmaceuticals companies, large manufacturers in the airplane or automotive industries – using semantic technologies for many different enterprise purposes. It boils down to having lots of data sources to reconcile information, like parts numbers to understand real time data flows, or obscure proteins in the drug discovery process. Semantic technology is very powerful for creating inferences about data and organizing the information in new and interesting ways.

The two main business problems that mainstream types of companies deal with are having lots of sources of customer names and addresses and trying to reconcile them out of their CRM and support systems and order processing systems — who is the customer and ensuring I have one customer record. That’s a very typical example. There are multiple databases of sources that were never designed to work together but you must be able to pull data out of them and rationalize the information. Traditionally that’s been done using ETL technologies and data hubs and data warehousing technologies.

The other common business problem is parts – lots of parts and suppliers, with different numbers even if they’re very similar. Trying to keep track of what’s what and what you can order from someone is very complicated. Semantic technology lets you say this part from supplier one is equivalent to this part from the other supplier.

There are even bigger possibilities for semantic technology. Think about business intelligence … What if BI tools could tap into existing data and provide you intelligence in real time. There are huge opportunities there to increase the value of your IT.

Read more

Steven Pinker is well on his way to a best selling book on, of all things: semantics. I haven’t finished it yet, but am finding it fascinating. What is surprising me is how popular it is. Must be a lot more armchair ontologists out there than I thought.
One of the things that sent me to the blog, though, was his quantification of a semantic distinction. It turns out that the insurance policy on the World Trade Center has a maximum payout of $3.5 billion per event. The $3.5 billion dollar semantic question is: did the two plane crashes constitute one event or two?

Slightly longer review

Read more

By Michael C. Daconta, Leo J. Obrst, and Kevin T. Smith

At the simplest level, the Resource Description Framework (RDF) is an XML-based language to describe resources. While the definition of “resource” can be quite broad, let’s begin with the common understanding of a resource as an electronic file available via the Web. Such a resource is accessed through a Uniform Resource Locator (URL). While XML documents attach metadata to parts of a document, one use of RDF is to create metadata about the document as a stand-alone entity. In other words, instead of marking up the internals of a document, RDF captures metadata about the “externals” of a document, like the author, the creation date, and type. A particularly good use of RDF is to describe resources, which are “opaque” like images or audio files. Figure 1 displays an application, which uses RDF to describe an image resource.

The RDFPic application is a demonstration application developed by the W3C to embed RDF metadata inside JPEG images. The application can work in conjunction with the W3C’s Jigsaw web server to automatically extract the RDF metadata from images stored on the server. As you see in Figure 1, the application loads the image on the right side and allows data entry in a form on the left side. The tabbed panels on the left side allow you to load custom RDF schemas to describe the image. The two built-in schemas available for describing an image are the Dublin Core (www.dublincore.org) elements and a technical schema with metadata properties on the camera used. Besides embedding the metadata in the photo, you can export the RDF annotations to an external file, as shown in Listing 1.

Figure 1. An RDFPic application describing an image. RDFPic is copyrighted by the World Wide Web Consortium. All Rights Reserved. www.w3.org/Consortium/Legal/

Figure 2. The RDF triple.

The first thing you should notice about Listing 1 is the consistent use of namespaces on all elements in the listing. In the root element , four namespaces are declared. The root element specifies this document is an RDF document. An RDF document contains one or more “descriptions” of resources. A description is a set of statements about a resource. The element contains an rdf:about attribute that refers to the resource being described. In Listing 1, the rdf:about attribute points to the URL of a JPEG image called shop1.jpg. The rdf:about attribute is critical to understanding RDF because all resources described in RDF must be denoted via a URI. The child elements of the Description element are all properties of the resource being described. Two properties [to note are] one in the Dublin Core namespaces and one in the technical namespace. The values of those properties are stored as the element content. In summary, this code demonstrates a syntax where we describe a resource, a resource’s properties, and the property values. This three-part model is separate from the RDF syntax. The RDF syntax in Listing 1 is considered to be one (of many) serializations of the RDF model. Now let’s examine the RDF model. The RDF model is often called a “triple” because it has three parts, as described previously. Though described in terms of resource properties in the preceding text, in the knowledge representation community, those three parts are described in terms of the grammatical parts of a sentence: subject, predicate, and object. Figure 2 displays the elements of the tri-part model and the symbology associated with the elements when graphing them.

Editor’s Note: This article is an excerpt of Chapter 5, “Understanding the Resource Description Framework,” in The Semantic Web: A Guide to the Future of XML, Web Services, and Knowledge Management (Wiley Publishing 2003).

Read more

Paula Gregorowicz
SemanticWeb.com Contributor

Much like in the music industry where there are so-called “overnight sensations” that toiled for years to create their success, web technology seems to sprout the “next big thing” out of nowhere. At least that is how it feels to me with the semantic web.

What is the semantic web, you say? According to Wikipedia, the semantic web is an evolving extension of the World Wide Web in which web content can be expressed not only in natural language, but also in a format that can be read and used by software agents, thus permitting them to find, share, and integrate information more easily. It is a vision of information that is understandable by computers, so that they can perform more of the tedious work involved in finding, sharing, and combining information on the web. The semantic web derives from Tim Berners-Lee’s vision of the Web as a universal medium for data, information, and knowledge exchange.

What does that really mean?

There are basically two types of information — data stored in some sort of database and information stored in unstructured ways (think — desktop applications, audio, video, etc.). Currently web applications can query databases effectively to bring back information stored in databases. If the query matches the data, viola, you have the right results. Unstructured data is more difficult for machines. Sure we have a variety of search technologies that help to manage that informational space, but anyone who follows the developments in the search game knows that there remain many challenges to a strictly machine-based approach. (After all, if it were simple and accurate for machines, why would a company like Mahalo www.mahalo.com even get started?)

With the semantic web, in theory, technology will be able to bridge the gap between all forms of data. The secret is in the metadata and the namespaces that tell the machines what the markup in another document really means.

What technology is involved?

The foundational pieces for the semantic web include URI’s (which identify resources) along with XML and namespaces. These drive the engine behind locating, marking up, and interpreting information so that machines can read and understand the data.

The OWL Web Ontology Language provides the construct for defining and instantiating web data models that need to be read and presented to machines rather than humans. What that means is that it provides the vocabulary for describing objects and how they relate.

Resource Description Framework (RDF) provides the metadata model which is a major component of the semantic web. Think of RDF as an XML-based language to describe resources. Using a subject — predicate — object format (called triples) it is used to express relationships between objects. Since the semantic web is all about defining relationships between disparate objects that can be read and interpreted by machines and presented to humans in a meaningful way you can see how RDF will drive the success (or lack thereof) of this new web.

What is the business case for semantic web?

In the article “The Business Case for Semantic Web,” the author talks about how organizations have tons of information but often don’t know how to find it, interpret it, or make meaningful connections with other, related information. This is not news as anyone involved with the web and with complex corporate intranets knows how challenging it can be to find something you need.

Read more