Performs research and maintains expertise in the theory, methodology, and application of discrete mathematics for application to the NIST measurement science program; in particular, maintains and applies expertise in mathematical subdisciplines such as combinatorics, graph theory, network science, operations research, optimization, discrete nonlinear dynamics, computational geometry, quantum mechanics, and information theory, for application in such areas as the study of fundamental models of physics, chemistry, biology, and information systems, complex systems analysis, pattern recognition, and quantum computing and communications; in collaboration with NIST and outside scientists, develops, analyzes, and applies related mathematical methods and tools for critical problems of measurement science at NIST; develops mathematical foundations for the measurement science of information systems.