Smart cyber-physical systems (S-CPSs) are complex engineered systems empowered by cyber-physical computing and equipped with the capability of reasoning, learning, adapting, and evolving. As an outcome of data-driven dynamic computing, reasoning capabilities, and the run-time obtained own knowledge, nonlinear and emergent behavior of S-CPSs whilst in operation is an open issue, not experienced in the case of conventional technical systems. This paper analyzes the technical issues of run-time operation and emergent behavior of S-CPSs, reviews the current understanding and state of advancement in designing S-CPSs for run-time, explores the paradox, and issues of designing for run-time adaptation, and synthesizes some general principles that can be taken into consideration when addressing the challenges, first of all, in the context of advanced manufacturing systems. This paper introduces four levels of CPSs according to reasoning capabilities and adaptation freedom of systems, and recognizes the paradox that a system with a higher level of freedom requires a higher level of self-control and resource management according to the overall objective of operation. Specific and common design principles are presented and critically assessed for each advancement level of CPSs. The principles synthesized by the authors provide only a partial fulfillment of the generic need. The planned future research addresses these issues and proposes (largely implementation and application independent) genuine principles for system developers.@en

Cyber-physical systems (CPSs) represent practical examples of the integration of bits and atoms in human and social contexts and contribute to the integration of neurons and genes into system implementation. Many experts believe that a deeper theoretical understanding of system adaptation will lead to the development of autonomous systems and adjustable autonomy. In terms of the introduction of changes, adaptation can be made during idle time or runtime. In addition, adaptation can be externally initiated and internally initiated. In terms of intentionality indispensable, planned, or self-decided adaptations are distinguished. Adaptations are planned during the design time, runtime, or in both. Internally initiated adaptation is self-adaptation, a form of system operation in which the goals and rules of adaptation are not provided by external controllers. Internally initiated control intertwines the logics of application functions and adaptation functions. This approach is based on programming language features, such as conditional expressions, parameterization, and exceptions in software (SW) systems.@en

Conventionally, a technical system is defined in the design phase and considers all important requirements and aspects. The expected operations and the circumstances of operations are to be known in advance. If these are known, then the designed system can even be validated before it is produced or launched on the market. Validation is typically based on predictive analyses or simulations. However, these do not apply completely in the case of smart systems such as smart cyber-physical systems (S-CPSs) which self-manage their operation, or at least a part of it. Being able to adapt during run-time and evolve over time, S-CPSs cannot be validated using conventional deterministic approaches. Typical examples of these self-managing systems are S-CPSs already used as instrumentation in the medical field. The above circumscribed situation stimulated our background research, the results of which are concisely summarized and critically concluded in this paper. The literature has been found fairly narrow in terms of novel validation approaches for self-managing systems. The literature proposes to share the tasks of operational and behavioral validation among the system designers and the technical systems themselves. While designers need prognostic approaches to validate system operation, systems need to construct validation plans and execute them at run-time. This requires additional, validation-specific functionalities and context-dependent mechanisms such as run-time validation frameworks or meta-models, objective-sensitive self-monitoring mechanisms, self-constraining and self-supporting mechanisms, and other enablers. Extensive foundational research and system prototype testing are deemed to be indispensable. To make the first small step in this direction, this paper proposes a concept for the validation of smart medical CPSs. This relies on the following hypothesis: If a system has the freedom for self-adaptation, then it should also be equipped with a self-control mechanism, meta-knowledge, and a supervisory controller. These additional resources enable purpose- and context-dependent semantic reasoning about the operational objectives and behavioral states. This paper suggests a number of topics for future research towards a run-time validation engine.@en