System designers have one goal in common: the system must behave according to the design requirements. Designers need to succinctly specify the behavioral requirements of a system. Peters in  proposes a technique for documenting system requirements in which the required system behavior is described in terms of the environmental quantities that the system is required to observe and control; these are modeled as functions of time.
This paper presents OXReq, a tool, based on Xylia [2,3], for authoring and processing of requirements documents. This tool employs two XMLs: one for storage, analysis, and verification of requirements documents, and another for presentation to and editing by human users. The grammars for these XMLs are defined by document type definitions (DTDs). Mathematical and tabular expressions are integral parts of requirements documents. OXReq builds on OpenMath  for encoding complex mathematical and tabular expressions in XML.
Using Xylia, XSLT, and a JavaCC generated parser, this tool provides the seamless transition from storage XML to presentation XML and vice versa. The plug-in mechanism of Xylia allows complex tasks to be performed on requirements documents, such as verification of internal consistency, completeness, and other properties of the documents, and generation of Oracles.
 Peters, Dennis K., "Deriving Real-Time Monitors from System Requirements Documentation", Ph.D. Thesis, McMaster University, 2000.
 Milley, Jonathan R., Norvell, Theodore S. and Peters, Dennis K., "The Xylia Toolkit, combining XML and Java", NECEC 2001.
 Shaker, Pouria, Norvell, Theodore S. and Peters, Dennis K., "Edits in Xylia: Preserving the Validity of XML Documents", NECEC 2002.
 Dewar, Mike, OpenMath Website, www.openmath.org.
Last modified: Fri 2004.07.09 at 15:55 NDT by Dennis Peters