A version 2.0 XML DTD has been issued by the MatML Working Group. The MatML project focused upon the distribution of materials property data is coordinated by the US National Institute of Standards and Technology (NIST). The MatML effort "is addressing the problems of interpretation and interoperability through the development of an Extensible Markup Language (XML) [Materials Property Data Markup Language] for materials data that will permit the storage, transmission, and processing of materials property data distributed via the World Wide Web. A MatML Working Group has been established and represents a cross section of the materials community with members from private industry, government laboratories, universities, standards organizations, and professional societies. The Working Group uses an online forum for discussing issues such as the scope of and specifications for MatML and has recently produced a working draft of the document type definition (DTD) for the markup language. The MatML DTD contains structures for transferring information concerning the material and its properties, terms which may help with the interpretation of the transferred data, and graphs. The DTD is the XML semantic and syntactic formalism that software will need to parse, interpret, and use the data contained in MatML documents." A 'Workshop on the Technical and Strategic Future of MatML' is being hosted by NIST on June 26-27, 2001 in Gaithersburg, MD; the workshop will consist of panels and open discussions of interest to the materials science and engineering community.
Problem statement from the NIST working group: "Materials property data distributed on the World Wide Web in documents using hypertext markup language (HTML) present two problems for computer applications intending to use the data: interpretation and interoperability. Since the data [represented in HTML, cf. Code Fragment from the NIST Ceramics WebBook] are not self-describing, one would need a complete data dictionary and glossary of terms as well as exact detailed knowledge of the document structure in order to write a computer application that uses these data without human intervention. . . it would be necessary to distinguish the measurement parameters, Magnetic Field and Temperature, from the property, Critical Current Density. Assuming a consistent structure within and across documents from the data source, it would then be possible to parse and interpret those data programmatically for subsequent use in another computer application. In the absence of tightly and consistently structured documents, a data dictionary, and a glossary of terms, however, interpretation arises as a key stumbling block for automated use of the materials property data contained in HTML documents. If interpretation of data were not an issue, the computer application developed to parse and use the data would likely encounter serious difficulties were it to try using data from other structurally dissimilar sources. Interoperability, then, would be a limiting condition for the use of the computer application across structurally dissimilar data sources even if data dictionaries and glossaries of terms were available..."