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Cyber-physical systems (CPS) are, in the words of NIST, “smart systems that include engineered interacting networks of physical and computational components” (NIST SP 1500-201, v1.0, June 2017). This guide is for researchers, proposal writers and research administrators who need a precise definition, a shared planning vocabulary and a map of how CPS research is funded.
What is a cyber-physical system?
A cyber-physical system is an engineered system in which computation and physical processes are tightly integrated, so that software decisions act on the physical world and physical measurements feed back into software. NIST’s Framework for Cyber-Physical Systems: Volume 1, Overview (SP 1500-201, edited by Edward Griffor, version 1.0, 79 pages) gives the definition quoted above and describes CPS and related systems, including the Internet of Things and the Industrial Internet, as having great potential across economic sectors. The NIST CPS Public Working Group was established in mid-2014 and names smart manufacturing, transportation, energy and healthcare among the application domains it considered.
Two points follow from the definition. First, the emphasis is on engineered and interacting networks: a CPS is judged by how its computational and physical parts behave together, not by either part alone. Second, CPS overlaps with several neighbouring fields rather than replacing them: control theory supplies methods for the feedback behaviour, systems engineering supplies lifecycle discipline, and cybersecurity addresses the exposure that comes from connecting physical processes to networks. Systems that act in the physical world through learned models are covered separately in embodied AI.
The NIST framework: facets and aspects
The NIST framework offers a vocabulary for describing a CPS across its life, organised into three facets and a set of cross-cutting aspects. It is useful in a proposal or study design because it forces the team to say which activity a piece of work addresses.
The three facets
| Facet | What it covers (per NIST SP 1500-201) |
|---|---|
| Conceptualization | Goals, functional requirements and organization of the system; the output is a conceptual model. |
| Realization | Detailed design, production, implementation and operation, supported by trade-off analyses and simulation. |
| Assurance | Confidence that the built CPS satisfies the conceptual model, expressed as claims, argumentation and evidence judged against design, policy, law and regulation. |
The nine aspects
Aspects group concerns that cut across the facets. NIST lists nine: functional, business, human, trustworthiness, timing, data, boundaries, composability and lifecycle. A practical use is as a checklist when scoping a project: for each aspect, record whether the work addresses it, assumes it, or leaves it out of scope.
Where cyber-physical systems research is applied
The NIST working group named smart manufacturing, transportation, energy and healthcare as the domains its framework addresses. Because the framework is domain-neutral, the same facet and aspect vocabulary lets a team in one domain compare its requirements and assurance arguments with a team in another.
How CPS research is funded
In the United States, the National Science Foundation runs a dedicated program, Cyber-Physical System Foundations and Connected Communities (CPS), under the Computer and Information Science and Engineering directorate’s Future Computing Research (Future CoRe) area. As read on the NSF program page on 2026-11-07, the program was published under solicitation NSF 25-543 (posted 2025-07-25, updated 2025-08-18), has two tracks, CPS-FR and CPS-CIR (a proposal title must include the track), and involves the Engineering, Social, Behavioral and Economic Sciences, Geosciences and STEM Education directorates as collaborating partners. NSF advises applicants to contact a CPS program officer before submitting. Check the program page for the solicitation’s current status and dates before planning a submission.
For the broader CISE portfolio see the NSF CISE core programs guide, and for defence-sponsored work see DARPA I2O.
Frequently asked questions
What is the difference between a cyber-physical system and the Internet of Things?
NIST treats them as related rather than identical: its framework describes CPS and related systems, including IoT and the Industrial Internet, together as having great potential across economic sectors. The CPS definition centres on engineered interacting networks of physical and computational components.
What does assurance mean for a CPS?
In the NIST framework, assurance is confidence that the built system satisfies its conceptual model, supported by claims, argumentation and evidence assessed against design, policy, law and regulation.
Which discipline owns CPS research?
No single one. NSF’s CPS program involves several directorates (CISE with ENG, SBE, GEO and EDU), which reflects the field’s mix of computing, engineering and application science.
Sources
- NIST, Framework for Cyber-Physical Systems: Volume 1, Overview, SP 1500-201 v1.0, June 2017: doi.org/10.6028/NIST.SP.1500-201 (read 2026-11-07). NIST’s 1500 series documents external perspectives, not official NIST positions.
- NSF, Cyber-Physical System Foundations and Connected Communities (CPS): nsf.gov program page (read 2026-11-07).
