Obsidian/.archive/Literature Notes/leePresentFutureCyberPhysical2015.md

authors	citekey	alias	publish_date	journal	volume	issue	pages	last_import
Lee, Edward A.	leePresentFutureCyberPhysical2015	leePresentFutureCyberPhysical2015	2015-03-01	Sensors	15	3	4837-4869	2025-07-30

The Past, Present and Future of Cyber-Physical Systems: A Focus on Models

Indexing Information

Published: 2015-03

DOI 10.3390/s150304837 #clock-synchronization, #cyber-physical-systems, #distributed-systems, #PRET-machines, #real-time-systems, #time-synchronization

#InFirstPass

[!Abstract] This paper is about better engineering of cyber-physical systems (CPSs) through better models. Deterministic models have historically proven extremely useful and arguably form the kingpin of the industrial revolution and the digital and information technology revolutions. Key deterministic models that have proven successful include differential equations, synchronous digital logic and single-threaded imperative programs. Cyber-physical systems, however, combine these models in such a way that determinism is not preserved. Two projects show that deterministic CPS models with faithful physical realizations are possible and practical. The first project is PRET, which shows that the timing precision of synchronous digital logic can be practically made available at the software level of abstraction. The second project is Ptides (programming temporally-integrated distributed embedded systems), which shows that deterministic models for distributed cyber-physical systems have practical faithful realizations. These projects are existence proofs that deterministic CPS models are possible and practical.>[!seealso] Related Papers

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Highlights From Zotero

[!tip] Brilliant As an intellectual challenge, CPS is about the intersection, not the union, of the physical and the cyber. It combines engineering models and methods from mechanical, environmental, civil, electrical, biomedical, chemical, aeronautical and industrial engineering with the models and methods of computerscience. This paper argues that these models and methods do not combine easily and that theconsequently CPS constitutes a new engineering discipline that demands its own models and methods. 2025-05-09 1:50 pm

[!fail] This ain't right His control logic was effectively acomputation, albeit one carried out with analog circuits and mechanical parts, and therefore, cyberneticsis the conjunction of physical processes, computation and communication. 2025-05-09 1:52 pm

[!tip] Brilliant the fog (like the cloud, but closer to the ground) 2025-05-09 1:53 pm

[!highlight] Highlight Engineers often conflate the model with the thing being modeled. For example, electrical engineersmay refer to an ODE as “the system” and use it to assert, for example, that “the system is stable.”Such a statement, however, is not a valid statement about a physical system. It is a statement about a model of the physical system. Arguably, any definitive statement about a system (stability, determinism,timeliness, reliability, safety) is in fact a statement about a model and not a statement about the thingbeing modeled. I call this idea the “Kopetz principle,” after Hermann Kopetz, from whom I learned it. Emphasizing the need to avoid conflating the model with the thing being modeled, Solomon WolfGolomb famously stated “you will never strike oil by drilling through the map” [2]. 2025-04-30 9:23 pm

[!done] Important Ptides leverages network clock synchronization, which I believe will become ubiquitous 2025-05-09 1:56 pm

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