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As is the case with many web technologies today, nearly every core piece of the Semantic Web is based on XML, from RDF to OWL to SPARQL.
That means that, for the most part, all it takes to build things for the Semantic Web is a good text editor - and, to date, the majority of Sematic Web applications and deployments have been built in exactly this way.
However, to be truly productive at working on Semantic Web applications, pretty much everyone would agree that dedicated tools are the way to go in order to help developers and authors better understand the unique ins and outs of creating and preparing information for the Semantic Web.
There have been a number of simple and free prototype tools built by World Wide Consortium members, such as the Tabulator, a simple tool that makes it possible to browse through complex RDF (Resource Description Framework) data directly from a standard web browser, and cwm a processing tool for Semantic Web data.
In addition, the SIMILE - or Semantic Interoperability of Metadata and Information in unlike Environments - Project at simile.mit.edu is working on building a set of open-source tools for the Semantic Web. Among the tools already available from SIMILE are Piggy Bank, a Semantic Web extension for the Firefox browser, and Welkin, a graphical visualization tool for RDF datasets.
But for those companies looking for commercial Semantic Web products, the market is finally beginning to gain steam as more vendors from the traditional web and web service development, search, data analysis and management fields are releasing products dedicated to creating and managing applications and data for the Semantic Web.
eWEEK Labs took a look at three products designed to help businesses build and manage Semantic Web solutions; Altova's SemanticWorks 2007, Intellidimension's RDF Gateway 2.3.4 and TopQuadrant's TopBraid Composer 2.0. All three of these programs are available in free evaluation versions and are worth checking out for any business interested in building Semantic Web solutions.
Altova's SemanticWorks 2007 is a Windows-based visual RDF and OWL (Web Ontology Language) editor. Altova has long been a strong player in the XML development market and anyone who has used their excellent XMLSpy XML development tool will instantly be at home in SemanticWorks 2007.
Using this tool we could create and edit RDF data files and OWL ontologies using a visual data map to control all of our core data relationships and definitions. We appreciated the visual tools but liked even more that we could quickly jump out of them to a standard code view of our files. SemanticWorks 2007 provided tools to check the validity of our syntax and semantic code and offered good feedback on errors or inconsistencies. Another nice touch let us save our OWL mappings as images which made it possible for us to share and display ontology information in collaborative settings.
Altova SemanticWorks 2007 is priced at $129 and can be found at www.altova.com.
Intellidimension's RDF Gateway was one of the first true Semantic Web products that we ever tested here at eWEEK Labs, when we evaluated version 1.0 back in 2003. From our recent tests of version 2.3.4, it doesn't look like much has changed--not that that is a bad thing. RDF Gateway is still a solid combination of a web server, application server and RDF gateway and is still a good way to get Semantic Web applications up and running.
However, it also remains a Windows-only application, and the product also still uses its own web scripting language known as RDF Server Pages (which are simple to create for anyone who has used Java Server Pages or similar languages). There are also no real editing tools in RDF Gateway though Intellidimension does currently have in a free beta an RDF editing tool called InferEd.
Most of the main improvements in RDF Gateway are in upgraded support for newer standards. RDF Gateway ships with its own ECMAScript-based query language called RDF Query Language, but it also now supports the official SPARQL query language.
A simple Windows querying tool that comes with RDF Gateway made it possible for us to create, test and deploy applications for the RDF Gateway server.
The product's setup wizards stepped us through deploying and running applications, and its browser-based administration interface enabled us to manage the server and control access and permissions. This interface (which is itself an RDF Gateway application) is pretty barebones but was useful for managing our RDF and Semantic Web application deployments.
Intellidimension offers a free personal version of RDF Gatway, as well as a professional edition that starts at $595, and an enterprise edition that starts at $1,995. For more information go to www.intellidimension.com.
As with many other applications nowadays that have anything to do with creating web applications or web services, TopQuadrant's TopBraid Composer 2.0 is an Eclipse-based development tool.
By far the main strength of TopBraid Composer is in ontology development and editing. We were greatly impressed with the depth of capability that TopBraid Composer gave us for visually designing very complex OWL ontologies.
The way TopBraid Composer laid everything out made it surprisingly easy to get a grasp on complex semantic applications. When editing an OWL file we could quickly view and configure it in multiple ways, with easy access to core settings, parameters and SPARQL queries with syntax checking.
We could switch quickly between multiple viewing formats, including a very good visual diagram, an RDF graph, a form-based window and a well-implemented source code view.
TopBraid Composer also does a good job of utilizing and supporting a wide variety of newer Semantic Web standards and draft or proposed standards, such as SWRL (Semantic Web Rule Language) and GRDDL (Gleaning Resource Descriptions from Dialects of Languages).
Creating next generation Semantic Web mashups is also a focus of TopBraid Composer, which included some cool built-in capabilities for creating classic mashups such as geolocation tools utilizing Google Maps.
TopBraid Composer, while available as a standalone product, is also part of TopQuadrant's TopBraid Suite, which also includes components for deploying and collaborating on the creation of Semantic Applications. TopBraid Composer is priced starting at $495 and can be found at www.topbraidcomposer.com.
The World Wide Web Consortium maintains a list of commercial products dedicated to building applications and data infrastructures (which includes well known products such as the Oracle database) at http://esw.w3.org/topic/CommercialProducts.
eWEEK's Emerging Technology Looks at the Semantic Web
Weaving the Semantic Web - What is the Semantic Web, how will it effect the web and business, and what is its future?
Using the Semantic Web in the Real World - A visual look at several real-world deployments of Semantic Web technology and how they compare to current methods
Podcast: The Challenges of the Semantic Web - In this podcast I speak to Tim Berners-Lee about the current status of the Semantic Web, the challenges it faces and its future. I also speak to Eric Miller of Zepheira and to Stephen Downes, a researcher at the National Research Council's Institute for Information Technology in Canada.
And more to come. Check back later this week as I'll be posting my full interview with Tim Berners-Lee.