Although Cyber-Physical Systems cover an extremely wide range of application areas, there are strong demands for scientific and technological understanding of the interactions among information processing, networking and physical processes. The science of Cyber-Physical Systems has broad applications, aided by specializations and additions for particular application domains. This science of CPS will allow us to design systems more economically by sharing both abstract knowledge and concrete tools. It will allow us to design more dependable cyber-physical systems, since we can apply best practices to the entire range of cyber-physical applications. The creation of this science and technology of Cyber-Physical Systems will be guided by the following major challenges and, thus, will cover the following topics:
- We need to realign abstraction layers in design flows. This realignment is very important to CPS because temporal abstractions in the physical part of the system entail a different model of computation than those in the cyber part. Abstractions developed for describing physical dynamics should be considered to resolve uncertainties of implementation platforms in an integrated fashion, such as network delays, finite word length and round-off errors. These changes in abstractions layers will allow the synthesis of computations with the considerations of physical system dynamics jointly that are robust against implementation uncertainties.
- We need to develop semantic foundations for composing heterogeneous models and modeling languages describing different physics and logics. For example, there is a strong need for co-design of control and computational implementation of the control. We need to develop mathematical frameworks that make semantics not only mathematically precise, but also explicit, understandable and practical for system developers as well as tool developers.
- We need to develop better understanding of compositionality in heterogeneous systems that allows us to take into account both physical and computational properties. It is important to recognize the different models of the physical and cyber parts of a CPS system. This view of compositionality will allow us to create large, networked systems that satisfy essential physical properties and deliver the required functionality in a reliable way.
- Cyber physical systems will have properties for which achieving full compositionality would be expensive or impractical. Development of technology for achieving predictability in partially compositional properties is a hard problem that must be addressed.
- We need a science and technology foundation for system integration that is model-based, precise, and predictable. Transforming system integration from a high risk engineering practice into a science-based engineering discipline is a huge challenge that will require close collaboration between industry and academia.
- We need new theories and methods for compositional certification of Cyber- Physical Systems. We must be able to compose CPS components into a large CPS system in such a way that we can reuse the certification of the components as evidence in certifying the larger system. Certification should rely more on verification and less on testing.
- We need a new infrastructure for agile design automation of Cyber-Physical Systems. As new application domains of Cyber-enhanced Physical Systems appear, we must be able to adapt our existing tool base rapidly, to help us design those systems without having to wait for entirely new tools to be created.
- We need to develop new open architectures for cyber-physical systems that will allow us to build national-scale and global-scale capabilities. These architectures should be defined by policies controlling their evolution, and invariants that need to be maintained - rather than by static structures - so that they can be more easily adapted to different operational conditions.
- We need architectures and tools that allow us to build trustworthy Cyber-Physical Systems from unreliable components. The issues shall include reliability, security & privacy, and safety.
- We need architectures and tools that allow us to build resilient and robust Cyber- Physical Systems, where resiliency is a system’s ability to maintain essential functionality despite partial failures, and robustness is the property of the system to function correctly irrespective of uncertainties in the environment. A CPS system should also tolerate malicious attacks from either the cyber or physical domains. These architectures should leverage open systems technologies to reduce design times and increase confidence.
- We need to address challenges of CPS with humans-in-the-loop, where many CPS applications feature humans as an important part of the system. Understanding, modeling, predicting, and optimizing overall system performance may therefore require properly accounting for the role of humans in the loop, and properly reducing uncertainty in the face of possible unpredictability that they introduce.
Cyber-physical technology can be applied in a wide range of domains, offering numerous opportunities in products. In order to meet the challenges of cyber-physical system design, we need to create a new systems science foundation and new technology infrastructure that will merge fundamental concepts from computer science and various engineering disciplines, and also to recognize that this new discipline will inject new ideas of its own. The topics of the research and system implementations of the following application domains would be targeted in ACM TCPS: healthcare, living space, control, electric power grid, automotive, aviation, and aerospace.