ITGumbo: spicing IT up

The information that must be displayed on the web page has been collected. Web resources have been identified within the statements in the information. These are web resources for which the content provider will either build an application or present them to a third party application (such as search engine). What information about these web resources will be presented to the application? The metadata of the web resource will be the information presented to the search engine.

At this moment we have: information and identified web resources. Now we have to define metadata.

We discussed the concept of "open market" and identified some issues that must be addressed. We discussed RDF language and its schema. We will discuss security in semantic web and advantages of semantic web later. Here we will start the discussion on transition to semantic web.

The evolution of the semantic web requires transition from one type of data representation to another, the HTML/XHTML and XML elements will be converted into RDF web resources with associated metadata. The information that was earlier owned by the web content provider may be shared and the former may not have all the intellectual property rights. The use of shared information may transform the appearance of data on the web.

According to Tim Berners-Lee the evolution of the semantic web is about "converting things". We identified three steps for conversion.

Usefulness of a system constitutes its usability and utility. Utility is the quality of being useful. Usability is the ease of use. Hence better usability can be designed with well defined utility. There are many definitions of the usability principles. Utility is also defined as one of the design goals for Human Computer Interface (HCI).

PACT analysis is one of the procedures used to determine the utility of an interactive system. The methods used for PACT analysis can be surveys, brainstorming in discussion groups, empirical data collected by heuristic evaluation and cognitive knowledge.

The <channel> element in a RSS 1.0 document summarizes the information contained in the web resource; as the name implies RDF Site Summary. The RSS 1.0 version describes the web resources metadata in conformance with the RDF specifications. The <item> elements in RSS 1.0 document are the RDF web resources summarized by this channel.

The <items> sub-element within a <channel> element declares these RDF web resources in a Seq container. These web resource declarations are defined by <item> element, hence this element must include a rdf:about attribute to identify the web resource that was declared in the Seq.

RDF schema provides built-in types to represent a group of 'things'; these 'things' are called members of the group. The group is either an open-ended container where any number of members can be added or a closed collection with pre-defined and limited number of members. The RDF container resource can be used to integrate scattered vocabulary. The RDF conatiner and collection resources can also be used to build distributed vocabularies for the semantic web. RDF specifications suggest that an RDF graph that contains some members does not preclude the existence of another RDF graph with additional members.

Web 3.0 - scattered vocabularies

RDF properties represent relationship between two resources represented by URI (hereafter called web resources). RDF properties themselves are web resources, the relationship between RDF properties and web resources is described by the RDF vocabulary description language RDF Schema. RDF schema provides terms for writing web resource description in RDF.

class: is a group of resources, and the resource is an instance of the class. Therefore all RDF resources are instance of a class.
property: since property is also a resource it is also an instance of a class.

RDF language design goal as suggested in W3C specifications is to provide:

• Generality - expression for the most propositions about any 'thing'

• Precision - to provide accurate expression

RDF language does not provide meaning of a 'thing' in all contexts, it only provides a formal notion for representing a meaning in a particular context. Therefore a particular triple <subject, predicate, object> of a 'thing' may apply to one set of inference rules and not to another. It is difficult to write a RDF vocabulary that is complete and can be applied to all decidable inference systems. As new 'thing' is identified the triples are added to the vocabulary.

RDF specifications state that RDF provides an open-world framework, in this framework anyone can refer to any resource. Though RDF semantics can be used to infer dependable reasoning from RDF data, it does not stop designers and developers from making contrary inferences.

These contrary inferences may lead to multiple disassociated independent vocabularies. The common vocabulary is the solution to this problem.

Example:

Subject- speed

It is known that 'speed' is the term used to describe the rate of movement of something. The URIref for this resource will provide information about all possible triples for: vehicle speed, data speed, light speed, sound speed, wind speed etc. If someone wants to describe narration speed of an artist, to be able to compare this property 'speed' must be defined as a RDF resource. Here instead of defining a new RDF resource for 'speed' in a new vocabulary a new property (Predicate) 'narration' may be added to the existing RDF graph for resource 'speed'.

Therefore adding new resources & properties to an existing vocabulary will build a common vocabulary database. This common vocabulary on the World Wide Web will make Transition from current HTML/XML implementations to Web 3.0 RDF/XML, OWL fast and easy with reduced cost. The objective is to capture all contrary inferences in a common vocabulary database.