Melissa Utzinger is a Senior Systems Engineer with the MITRE Corporation focusing on interface development, design and specification. For the past three years Melissa has made significant contributions to the establishment and development of a real-time System-of-Systems XML standardization specification for the Missile Defense Agency (MDA). In September 2006 she was awarded the Director’s Award acknowledging her critical role to this effort. In addition, she serves as the MDA DoD Metadata Registry sub-namespace manager, MDA representative to the Joint Air and Missile Defense Community of Interest (COI), and MDA representative to the XML-Implementation Management Subgroup (IMSG). She has been particularly interested in the forward and backward compatibility trade-offs and approaches to XML Schema and continues to seek out innovative solutions for typical XML problems.