It may seem that the last thing the world needs is another Web standard, but there is always room for an intelligent addition. A new language known as DAML addresses an important, unmet need- making Web sites understandable to programs and nontraditional browsing devices.
DARPA (Defense Advanced Research Projects Agency) Agent Markup Language is a step toward what Tim Berners-Lee, the creator of the World Wide Web, calls a “semantic Web” where agents, search engines and other programs can read DAML mark up to decipher meaning-rather than just content-on a Web site. A semantic Web also lets agents utilize all the data on all Web pages, allowing it to gain knowledge from one site and apply it to logical mappings on other sites.
Enhanced searching of this type would require a lot of groundwork: Once DAML is available, authors at individual sites would have to add DAML to their pages to describe the content.
Jim Hendler, a University of Maryland professor who is one of DAML’s creators, told PC Week Labs that before long the Web will involve many machine-to-machine connections with the help of semantic languages such as DAML. Hendler works on DAML for DARPA, a research and development organization for the Department of Defense.
Although DAML is still in an early stage, Hendler has begun working with Berners-Lee and the World Wide Web Consortium to make sure that DAML fits with the W3C’s plans for a semantic Web, which would be based primarily on RDF (Resource Description Framework), the W3C’s metadata technology for adding machine- readable data to the Web. Hendler said he expects to have a working draft of DAML available by the summer.
Basis in XML bodes well
Like RDF, DAML is based on XML (Extensible Markup Language), which should help it integrate with other Web technologies. A site developer would use DAML in much the same way that HTML metatags are used, describing content on a page using markup that is generally invisible to site visitors. A critical difference is that DAML markup would be easily understandable to DAML-enabled user agents and programs, whereas most metatags are proprietary and have no contextual meaning for general search applications.
A DAML-enabled agent doing a search for an expert on XML (see chart, right) might combine information from diverse sites to produce a result that would be missed by an agent or program in use today. On one page, the agent might discover the existence of an advanced university course on Web development that covers XML in detail. On another page, it might find the course number for this site. Then, on a third page, it might discover the name of the professor teaching the course. Although none of the sites individually has enough information to lead the agent to the professor’s name, the combination of the content described in DAML yields the enhanced search result.
Hendler said he also sees tremendous possibilities for DAML as an enabler for future devices hooked to the Web. For example, he described a scenario in which an appliance would be able to respond to an electronic recall or defect notice about one of its parts. A query initiated by the parts manufacturer would detect the part data in DAML on the appliance’s embedded Web connection.
Another area of use for DAML would be the ability to do queries that can cut across the varied and confusing jargon used by different industries. This would be especially useful in military queries, where, for example, the same jet could be listed as an F-14 or a Tomcat.
Some of the biggest barriers to technologies such as DAML are the lack of tools to create it and the dearth of user agents that understand it. An experienced coder would be able to insert DAML mark up through an editor, but Hendler said the technology will reach its potential more quickly if page-creation tools simplify its use. An effective tool would step users through the process of describing the content on their pages, then insert the proper DAML automatically.
One advantage DAML may have over other emerging Web technologies is the involvement of DARPA, which has been instrumental in the creation of the Internet and many Internet technologies. Hen dler expects DARPA to make all the basic tool sets for DAML available and to encourage the participation of the Web development community. Also, DARPA will offer support to those willing to create tools and user agents that enable DAML.