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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Models provide understanding and physical modeling is as important in a Cyber Physical System as cyber modeling. By using category theory, which includes syntax for describing the system and semantics for using the model, we can provide a foundation to unify modeling.
- It will be possible to group the radioactive wastes from the perspectives on Systems, Structures and Components (SSCs). This paper covers systematic approaches for deregulating grouped decommissioning wastes. SSCs decomposition structure, mass flow of decommissioning waste, sequence and storage time estimation method for deregulation, and interrelationship between them are presented. The expected benefit is the ability possibly to apply deregulation process to SSCs because SSCs breakdown structure is connected with mass flow of decommissioning waste, deregulation option, and storage time. This allows for the application of deregulation strategies and processes on SSCs basis and can enhance the rationale and traceability of the waste grouping. The sequence for deregulation reflects the logic of ensuring that radioactive nuclides meet self-disposal criteria and storing or disposing radioactive wastes if not met. (authors)
In the past few decades, increasing complexity in modern engineering systems has been driven by the integration of a large number of components and by the fact that the system operations involve many disciplines (e.g., thermal-hydraulics, plant operations, cyber-security). Current safety/reliability modeling approaches to such systems are labor intensive, difficult to learn, and rely heavily on simplistic Boolean logic to depict failure propagation and accident progression. While these methods serve well for simple systems (i.e., linear causal systems with limited small inter- and intra-system interactions), their results are difficult to verify when modeling complex systems (typically performed through the extensive use of modeling assumptions). The development of new methods is addressed to meet these challenges through a model-based system engineering (MBSE) lens. Under MBSE philosophy, every aspect of the system (form or function) is represented by a model that completely characterizes its architecture or behavior. MBSE approach greatly improves the management of design, analysis and verification of complex systems. An integration of Dynamic Probabilistic Risk Assessment (DPRA) methods with MBSE models is proposed to perform safety/reliability analyses of engineering systems. In particular, MBSE representation of the system (performed using Systems Modeling Language [SysML]) is coupled with DPRA methods to automatically generate event trees and fault trees.