  Digital Engineering, the digital transformation of engineering to leverage
digital technologies, is coming globally. This paper explores digital systems
engineering, which aims at developing theory, methods, models, and tools to
support the emerging digital engineering. A critical task is to digitalize
engineering artifacts, thus enabling information sharing across platform,
across life cycle, and across domains. We identify significant challenges and
enabling digital technologies; analyze the transition from traditional
engineering to digital engineering; define core concepts, including
"digitalization", "unique identification", "digitalized artifacts", "digital
augmentation", and others; present a big picture of digital systems engineering
in four levels: vision, strategy, action, and foundation; briefly discuss each
of main areas of research issues. Digitalization enables fast infusing and
leveraging novel digital technologies; unique identification enables
information traceability and accountability in engineering lifecycle;
provenance enables tracing dependency relations among engineering artifacts;
supporting model reproducibility and replicability; helping with
trustworthiness evaluation of digital engineering artifacts.
